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Solenopsis (Diplorhoptrum) (Hymenoptera: Formicidae) of Florida

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Solenopsis (Diplorhoptrum) (Hymenoptera: Formicidae) of Florida
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Diplorhoptrum
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Formicidae
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Thompson, Catherine R., 1952-
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xi, 115 leaves : ill. ; 28 cm.

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Animal nesting ( jstor )
Ants ( jstor )
Female animals ( jstor )
Head ( jstor )
Larvae ( jstor )
Petioles ( jstor )
Punctures ( jstor )
Species ( jstor )
Thorax ( jstor )
Tumuli ( jstor )
Ants ( fast )
Dissertations, Academic -- Entomology and Nematology -- UF
Entomology and Nematology thesis Ph. D
Florida ( fast )
City of Gainesville ( local )
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bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

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Thesis--University of Florida.
Bibliography:
Includes bibliographical references (leaves 105-114).
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Also available online.
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Typescript.
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Vita.
Statement of Responsibility:
by Catherine R. Thompson.

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SOLENOPSIS (DIPLORHOPTRUM) (HYMENOPTERA:FORMICIDAE) OF FLORIDA





By

Catherine R. Thompson















A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY











UNIVERSITY OF FLORIDA

1980









































Copyright 1980

by

Catherine Rose Thompson













ACKNOWLEDGEMENTS



I wish to thank my committee chairman, Dr. William F. Buren, for

his help and encouragement on all phases of this study, and Drs.

C.S. Lofgren, D.G. Griffin, S.H. Kerr and R.I. Sailer for their

assistance in preparing this dissertation.

I am grateful to Greg Erdos for instruction on SEM techniques,

to Dr. J.L. Nation for colony laboratory space and to P.T. Carlysle

for scanning electron micrographs of S. (D.) picta and S. (D.) cor-

ticalis. I appreciate Dave Gowan's time for photographs of S. (D.)

pergandei tumuli.

Many thanks are also due to Dr. D.P. Wojcik for access to his

collections and literature files.

I am also grateful to Dr. J.C. Nickerson for his specimens of

S. (D.) corticalis and his continuous encouragement and advice.




















iii















TABLE OF CONTENTS

PAGE

ACKNOWLEDGMENTS . . . . . . . . . . . .. iii

LIST OF FIGURES . . . . . . . . . . . vii

ABSTRACT. . . . . . . . . . . . . . x

INTRODUCTION. . . . . . . . . . . . . 1

REVIEW OF LITERATURE. . . . . . . . . . . 3

Taxonomy . . . . . . . . . . . . 3
Distribution . . . . . . . . . . . 4
Economic Importance. . . . . . . . . . 5
Biology and Ecology. . . . . . . . . . 8
Venom Chemistry. . . . . . . . . . ... 11

MATERIALS AND METHODS . . . . . . . . . . 12

Taxonomy . . . . . . . . . . . . 12
Lactophenol Fixation. . . . . . . .. . 13
Scanning Electron Micrography . . . . . . 14
Field Studies. . . . . . . . . . .. 15
Collecting Techniques . . . . . . . . 15
Naves Traps . . . . . . . . . . 16
Local Distribution Study. . . . . . . ... 17
Use of Light Trap Collections . . . . . . 18
Laboratory Studies . . . . . . . . . . 18
Colony Nest Materials . . . . . . . . 18
Feeding . . . . . . . . . . . 20
Queen Colony Founding . . . . . . . . 20

RESULTS . . . . . . . . . . . . . 22

Section I; A Taxonomic Review of the S.
(Diplorhoptrum) of Florida . . . . . . . 22
Introduction . . . . . . . . . ... 22
Key to S. (Diplorhoptrum) Species of Florida. . . 24
1. Solenopsis (Diplorhoptrum) abdita n.sp.. . 27
Diagnosis . . . . . . . 27
Description . . . . . . . 27
Worker . . . . . . . 27
Female . . . . . . . 28
Male . . . . . . . 29

iv








PAGE

Types . . . . . . . . . 29
Discussion. . . . . . . .. 29
2. Solenopsis (Diplorhoptrum) carolinensis
Forel . .. . . . . . . 31
Diagnosis . . . . . . . . 31
Discussion. . .. . . . .31
3. Solenopsis (Diplorhoptrum) corticalis Forel. 33
Diagnosis . . . . . . . . 33
Discussion . . . . . . .. 33
4. Solenopsis (Diplorhoptrum) molesta (Say) . 34
Diagnosis . . . . . . . . 34
Discussion . . . . . . .. 34
5. Solenopsis (Diplorhoptrum) nickersoni n. sp. 36
Diagnosis . . ..... . . . 36
Description . . . . . . . 36
Worker . . . . . . . 36
Female . . . . . . . 37
Male . . . . . . . 37
Types . . . . . . . . . 37
Discussion . . . . . . 38
6. Solenopsis (Diplorhoptrum) pergandei Forel 40
Diagnosis . . . . . . . . 40
Discussion . . . . . . .. 40
7. Solenopsis (Diplorhoptrum) picta Emery . . 42
Diagnosis . . . . . . . . 42
Discussion . . . . . . .. 42
8. Solenopsis (Diplorhoptrum) reinerti n.sp.. 43
Diagnosis . . . . . . . . 43
Description . . . . . . . 43
Worker . . . . . . . 43
Female . . . . . . . 44
Male . . . . . . . 45
Types . . . . . . . . . 45
Discussion . . . . . . .. 45
9. Solenopsis (Diplorhoptrum) tennesseensis
M. R. Smith. . . . . . . .. 46
Diagnosis . . . . . . . . 46
Discussion. . . . . . . .. 46
10. Solenopsis (Diplorhoptrum) texana Emery. . 47
Diagnosis . . . . . . . . 47
Discussion. . . . . . . . 47
11. Solenopsis (Diplorhoptrum) truncorum Forel . 48
Diagnosis . . . . . . . . 48
Discussion . . . . . . 48
12. Solenopsis (Diplorhoptrum) xenovenenum n.sp. 49
Diagnosis . . . . . . . 49
Description . . . . . . . 49
Worker . . . . . . . 49
Female . . . . . . . 50
Male . . . . . . . . 51
Types . . . . . . . . . 52
Discussion. . . . . . . .. 52

v








PAGE

Section II. Subterranean Distribution of
Diplorhoptrum Species . . . . . . . . . 71
Section III. The Mating Flights of S. (D.) pergandei . 88
Tumuli Construction. . . . . . . . .. 88
Flight Factors . . . . . . . . . . 89
Flight and Postflight Activities . . . . . 90
Section IV. The Role of S. (Diplorhoptrum) as Underground
Predators . . . . . . . . . . . . 95
Preliminary Experiments. . . . . . . ... 95
Predation on Fire Ant females. . . . . . ... 95
Predation on Diaprepes abbreviatus Larvae. . . . 96

SUMMARY. . . . . . . . . . . . . . .. 99

GLOSSARY . . . . . . . . . . . . . . 102

APPENDIX . . . . . . . . . . . . . . 104

LITERATURE CITED . . . . . . . . . . . . 105

BIOGRAPHICAL SKETCH. . . . . . . . . . . .. 115






























vi














LIST OF FIGURES

FIGURE PAGE

1 Lateral view of worker of S. (D.) abdita n.sp. (65X). . 54
2 Head of the worker of S. (D.) abdita n.sp. (120X) . . 54

3 Petiole and postpetiole of worker of S. (D.) abdita
n.sp. (340X). . . . . . . . . . . .. 54

4 Dorsal view of worker of S. (D.) abdita n.sp. (50X) . 54

5 Lateral view of worker of S. (D.) carolinensis Forel
(60X) . . . . . . . . . . . . . 56

6 Head of worker of S. (D.) carolinensis Forel (130X) . 56

7 Petiole and postpetiole of worker of S. (D.) carolinensis
Forel (290X). . . . . . . . . . . .. 56

8 Dorsal view of worker of S. (D.) carolinensis Forel
(56X) . . . . . . . . . . . . . 56

9 Lateral view of worker of S. (D.) corticalis Forel (90X). 58

10 Head of the worker of S. (D.) corticalis Forel (200X) . 58

11 Petiole and postpetiole of worker of S. (D.) corticalis
Forel (360X) . . . . . . . . . . .. 58
12 Dorsal view of worker of S. (D.) corticalis Forel (65X) 58

13 Lateral view of worker of S. (D.) nickersoni n.sp. (75X). 60

14 Head of the worker of S. (D.) nickersoni n.sp. (120X) . 60
15 Petiole and postpetiole of worker of S. (D.) nickersoni
n. sp. (420X) . . . . . . . . . . . 60
16 Dorsal view of worker of S. (D.) nickersoni n.sp. (65X) 60

17 Lateral view of worker of S. (D.) pergandei Forel (79X) 62

18 Head of the worker of S. (D.) pergandei Forel (98X) . 62



vii









FIGURE PAGE

19 Petiole and postpetiole of worker of S. (D.) pergandei
Forel (165X). . . . . . . . . . . .. 62

20 Dorsal view of worker of S. (D.) pergandei Forel (75X). 62

21 Lateral view of worker of S. (D.) picta Emery (70X) . 64

22 Head of the worker of S. (0.) picta Emery (140X) . . 64

23 Petiole and postpetiole of worker of S. (D.) picta
Emery (378X). . . . . . . . . . . .. 64

24 Dorsal view of worker of S. (D.) picta Emery (70X) . 64

25 Lateral view of worker of S. (D.) reinerti n.sp. (90X). 66

26 Head of the worker of S. (D.) reinerti n.sp. (140X) . 66

27 Petiole and postpetiole of worker of S. (D.) reinerti
n.sp. (460X) . . . . . . . . . . 66

28 Dorsal view of worker of S. (D.) reinerti n.sp. (50X) . 66

29 Lateral view of worker of S. (D.) xenovenenum n.sp.
(83X) . . . . .. . . . . . . . 68

30 Head of the worker of S. (D.) xenovenenum n.sp. (150X).. 68

31 Petiole and postpetiole of worker of S. (D.)
xenovenenum n.sp. (460X). . . . . . . . .. 68

32 Dorsal view of worker of S. (D.) xenovenenum n.sp. (84X). 68

33 Cluster of mating flight tumuli of S. (D.) pergandei
Forel . . . . . . . . . . . . . 70

34 Mating flight tumulus of S. (D.) pergandei Forel. .. . 70

35 Mating flight tumulus of S. (D.) pergandei Forel. .. . 70

36 Example of Naves trap samples of Diplorhoptrum and other
species distribution in a long leaf pine-turkey oak woods
on June 24, 1979, at Gainesville, Florida . . . . 72
37 Diplorhoptrum species captured by Naves trap in an open
field at Gainesville, Florida, from June 1979-June 1980 73

38 Diplorhoptrum species captured by Naves trap in a long
leaf pine-turkey oak woods at Gainesville, Florida,
from June 1979-June 1980. . . . . . . . .. 74


viii









FIGURE PAGE

39 Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) carolinensis
in an open field at Gainesville, Florida. . . . .. 79

40 Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) abdita in an open
field at Gainesville, Florida . . . . . . . 80

41 Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) carolinensis in
a long leaf pine-turkey oak woods at Gainesville,
Florida . . . . . . . . . . . . 81

42 Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) abdita in a long
leaf pine-turkey oak woods at Gainesville, Florida. . 82

43 Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) xenovenenum
in a long leaf pine-turkey oak woods at. Gainesville,
Florida . . . . . . . . . . . . 83

44 Number of months each trap site in an open field at
Gainesville, Florida, was positive for three species of
Diplorhoptrum (June 1979-June 1980) . . . . . 84

45 Number of months each trap site in a long leaf pine-turkey
oak woods at Gainesville, Florida, was positive for
three species of Diplorhoptrum (June 1979-June 1980). . 85

46 Correlation of S. (D.) pergandei mating flights with
times of sunrise in Gainesville, Florida. . . . .. 91


















ix














Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

SOLENOPSIS (DIPLORHOPTRUM) (HYMENOPTERA:FORMICIDAE)
OF FLORIDA

By

Catherine R. Thompson

August, 1980

Chairman: Dr. William F. Buren
Major Department: Entomology and Nematology

Prior to this study, six species of the subgenus Solenopsis

(Diplorhoptrum) were reported from Florida. In the present study,

four new species were found in the state. New information on S.

(Diplorhoptrum) prevalence, mating flights and role as predators was

obtained.

Review of the literature on Diplorhoptrum indicated that these

were thief-ants, present in relatively small numbers in the soil, and

usually in close association with nests of larger ants. Use of unique,

baited traps revealed Diplorhoptrum in unexpectedly large numbers with

a wide distribution in the soil. The ants were present in all but

extremely hydric habitats in Florida.

In this study, eight species of Diplorhoptrum were found: six

subterranean species, and two arboreal species. Four species previously

reported from Florida were not found. Examination of available voucher

specimens showed these to be misidentified. It seems possible that

authentic specimens of some of these species will eventually be found


x








in Florida. Independent studies have shown that the venom of one of the

new species contains (5Z,8E)-3-heptyl-5-methyl pyrrolizidine, the first

recorded occurrence of this substance in any animal or plant.

In subterranean studies, 50 traps each in an open field and a long

leaf pine-turkey oak woods were baited each month for a year. Five

Diplorhoptrum species came to the traps, three of which were new. The

dominant species in both habitats was S. (0.) carolinensis, while S. (D.)

pergandei was found only in the woods site, and the remaining species

were present in both habitats. The nest locations and foraging terri-

tories were mapped and found to have mosaic patterns. Ant activity

nearly stopped between October and November and did not reach high levels

again until the following May. Soil temperature is probably a major fac-

tor in this activity pattern. May soil temperatures were five to seven

degrees higher than those in April.

The only Diplorhoptrum species which constructed nest structures at

the soil surface was S. (D.) pergandei. These structures were crenelated

tumuli constructed for mating flights. The tumuli apparently allow more

sexuals to remain near the soil surface and also provide a surface for

flight takeoff. Mating flights for this species took place one half hour

before dawn from June through August, mostly when there had been rain

in the previous 24 hours.

The predatory activities of Diplorhoptrum were studied. They
readily killed and consumed newly mated imported fire ant queens,

Solenopsis invicta Buren. Several Diplorhoptrum species were also found

to kill and eat the larvae of the Sugar Cane Rootstalk Borer, Diaprepes

abbreviatus (L.). The indications are that Diplorhoptrum species may be
important subterranean predators and should be further investigated for

their potential as biological control agents.

xi














INTRODUCTION


There are approximately 8,000 known taxa of ants in the world, and

the habits exhibited are extremely diverse (Wilson, 1971). Three

principal ecological types may be said to exist in the Formicidae.

These are: I. Arboreal species, ants which nest in trees and forage

for food or obtain their food in trees or non-aborescent plants, II.

Terrestrial ants which nest in the soil and forage for food mostly on

the soil surface, and III. Subterranean or cryptobiotic ants, ants

that nest and forage underground or beneath debris seldom coming to the

soil surface. Species may, of course, occupy more than one of these

habitats.

Cryptobiotic ants are interesting academically because they often

are highly modified structurally Ants of the generally cryptobiotic

tribes Dacetini and Basicerotini, as well as other aberrant genera,

have been described and figured in many papers, of which Brown (1962),

Brown and Kempf (1967), Brown (1974) and Brown (1977) are examples.

The highly modified structures of these ants probably adapt them for

specialized predation on soil arthropods and are fortuitously useful

in taxonomic studies.

Subterranean ants are generally thought to be lestobiotic.

Solenopsis (Diplorhoptrum) as well as related subterranean genera

such as Oligomyrmex, Carebara, Carebarella are also more generalized

in structure. They have few specialized features which makes them


1






2

difficult to study taxonomically. Whitcomb et al. (1972) and Buren

et al. (1977) suggested that this group of genera and species might be

much more important as generalized subterranean predators than had

been previously suspected, and that their role in lestobiosis might

be secondary.

These studies were undertaken as an investigation into the

abundance, ecology, taxonomy, and predatory importance of these ants

in Florida. The data will revise thinking on the importance of these

predators in the subterranean ecosystem. The study also helps to

emphasize the need for similar studies on a world-wide basis.














REVIEW OF LITERATURE


Taxonomy


The genus Solenopsis is essentially cosmopolitan and is found in

all but the coldest parts of the world. The genus was divided by

Creighton (1950) into three subgenera: Solenopsis, Euopthalma and

Diplorhoptrum. The painful stings inflicted by members of the

Solenopsis (Solenopsis) group have attracted public attention as the

red Imported Fire Ant Solenopsis invicta Buren continues to spread in

the southern and southwestern U.S.

While not endearing themselves to the general public, the genus

Solenopsis is also no favorite of ant taxonomists. Creighton (1950)

grumbled "The student of North American ants may count himself fortunate

that so few species of this difficult genus occur in our latitudes"

(p.226). The worker caste in Solenopsis has undergone extreme con-

vergence, making identification to species difficult. Unfortunately

most of this convergence has occurred in Diplorhoptrum.

The taxonomic postion of Diplorhoptrum is subject to discussion.

Ettershank, in his revision of the Solenopsini (1966), synonymized

Diplorhoptrum under Solenopsis. Baroni-Urbani (1968) resurrected the

group and gave it full generic status. Unfortunately he based his

determination on the male genitalia of the common European species,

S. (D.) fugax (Latreille), without knowledge of the Neartic and Neo-

tropical fauna. Although Creighton suspected that male and female

3






4


morphology may indeed be the only reliable source of characters on

which to base Diplorhoptrum taxonomy, the fact remains that at present

few of the males are known. For this reason American myrmecologists

have been reluctant to accept Baroni-Urbani's work (pers. comm., W. F.

Buren). Retaining Diplorhoptrum as a subgenus may be acceptable simply

for convenience: as a group Diplorhoptrum are usually small, mono-

morphic species as opposed to the larger, polymorphic, free-living fire

ants (MacConnell et al., 1976). All S. (Diplorhoptrum) species have the

2nd and 3rd joints of the funiculus distinctly broader than long, whereas

in S. (Solenopsis) and (Euopthalma) species these joints are longer than

broad.

To search the literature on Diplorhoptrum, one must be aware that

the species most frequently published upon, S. (D.) molesta, is also

found under five synonyms: Myrmica molesta Say, Myrmica minuta Say,

Myrmica exigua Buckley, Solenopsis debilis Mayr, and Solenopsis

molesta (Say).

There has been an unfortunate tendency to identify every small

yellow thief ant as S. (D.) molesta. The problem is compounded by the

fact that S. (0.) molesta is the only economic pest in the Diplorhoptrum

group. As a result much of the literature concerning S. (D.) molesta

may be based on misdeterminations.


Distribution

Creigton (1950) listed 12 taxa of Diplorhoptrum for North America.

The most recent compilation (Smith, 1979) also contains 12 taxa: 10 from

Creighton's original list, one species renamed, and one placed

in synonomy. At least one Diplorhoptrum species has been reported




5


from each of the contiguous 48 states with S. (D.) molesta (Say), the

most widespread species, reported from 30 states. The species reported

from Florida are S. (D.) molesta (Say), S. (D.) pergandei Forel,

S. (D.) picta Emery, S. (D.) tennesseensis Smith, S. (D.) texana Emery,

and S. (D.) truncorum Forel.


Economic Importance

Although not as notorious as their fire ant relatives, Diplorhoptrum,

or thief ants as they are commonly called, contains one species,

Solenopsis (Diplorhoptrum) molesta (Say), which is a pest in fields and

dwellings. As a result of this pest status, and erroneous identifi-

cations, most of the literature deals with this species. Although

Creighton (1950) reported it to be distributed only in the central and

eastern states, it has subsequently been reported from eight of the 11

western states (Appendix).

S. (D.) molesta is best known as a economic pest of sorghum.

The ant is known as the "kafir ant" in Kansas (Bryson, 1941; Hayes,

1925) where it has been called the single most damaging pest of planted

sorghum (Burkhardt, 1959). The ants diminish sorghum stands by feeding

on germinating sorghum seed (Young and Howell, 1964). They have

destroyed thousands of acres of sorghum necessitating one to six

replantings and then not always with a resultant full stand (McColloch

and Hayes, 1916). Srivastava and Bryson (1956) found that tilling the

soil, planting early, and using various insecticides or insecticide-

fungicides prior to planting helped avoid damage. All of the com-

pounds tested were effective, while the ants damaged 50% of the check

seeds. McColloch and Hayes (1916) found that only late plantings were






6


damaged. Early planting, along with seed treatment, fall plowing, and

surface planting have essentially eliminated the kafir ant problem.

S. (D.) molesta has been reported to eat out the interiors of corn

kernels, and in New York is known as the "little yellow ant" (Fitch,

1856) and the "yellow field ant" (Felt, 1916). There are reports of

strawberries (Fitch, 1920) and blackberries (Webster, 1893) damaged by

S. (D.) molesta. This ant may also indirectly damage crops through its

habit of tending various species of aphids (Landis, 1967; Smith &

Morrison, 1916; Webster, 1893). It attacked the cocoons of the Japanese

beetle parasite Tiphia and killed 20% in the laboratory (White, 1940).

Smith (1965) reported S. (D.) molesta as a host of a poultry tapeworm.

S. (D.) molesta is one of only two of our native ant species which
invades homes (Wheeler, 1910). Herrick (1921) reported on the "little

fiery ant" which invaded kitchens. While Forbes (1896, 1920) and

Fitch (1856) stated that this ant had a sweet tooth, Back (1937) said

that it fed "almost entirely" on greasy substances. It is possible that

a number of Diplorhoptrum species may be involved. S. (D.) molesta

validiuscula Emery is a common pest in California homes where it lives

in crevices around sinks and feeds on greases, meats, and cheese

(Mallis, 1941). Among the more curious of S. (D.) molesta dietary

preferences was an insect collection (Fitch, 1856) while an

artist complained that S. (D.) molesta was eating his paints (Webster,

1893).

Nearly as many reports in the literature point to S. (D.) molesta

as a valuable predator as malign this species as an economic pest.

Brooks (1906) observed S. (D.) molesta in large numbers feeding on

grape curculio, Craponius inaequalis (Say), larvae. Theant killed





7


walnut curculio larvae, Conotrachelus juglandis Lec., in young black

walnuts on the ground (Brooks, 1910). It attacked boll weevil larvae,

Anthomomis grandis Hubner (Hunter & Pierce, 1912; Hunter & Hinds, 1904;

Pierce, 1912) was observed carrying chinch bug eggs, Blissus leucopterus

(Say), (Headlee & McColloch, 1913) and eggs and small larvae of the

cabbage maggot Phorbia braassicae Bouch6 (Schoene, 1916). In studies

on the striped earwig, Labidura riparia (Pallas), spraying heptachlor to

control S. (D.) molesta appeared to increase earwig populations. S. (D.)

molesta was subsequently observed feeding on earwig eggs in experimental

field plots (Gross & Spink, 1969).

S. (D.) molesta seems to be particularly important as a predator

on codling moth, Carpocapsa pomonella Linn., larvae and pupae (Brooks

& Blakeslee, 1915; Jaynes & Marucci, 1947). The workers cut small

characteristic holes in the cocoons, accounting for 2.5 to 64.2% of all

attacked cocoons. Those near the colony site were killed by the ants in

2-5 minutes. S. (D.) molesta is listed as a predator in Arkansas cotton

fields (Whitcomb et al., 1972; Whitcomb & Bell, 1964). S. (D.) molesta

has been found living with S. invicta and richteri Forel where it was

seen eating eggs and early larval instars of S. invicta (Collins &

Markin, 1971; O'Neal, 1974). Interestingly, S. (D.) molesta was un-

affected by the Mirex bait used to kill S. invicta in Louisiana (Markin

et al., 1974). Ayre (1963) fed S. (D.) molesta colonies both live and

dead insects of a number of species. The ants consumed 39 of 49 live

insects and 53 of 54 dead insects. They also ate eggs of the weevil

Sitona scissifrons Say. Ayre concluded that S. (D.) molesta "may be

as effective a predator as those species that capture larger insects,"

but "limited in their choice of food because they are small" (p. 715).




8


The role of other Diplorhoptrum species as predators is not nearly

as clear. Published reports are few. S. (D.) texana was observed

attacking boll weevil larvae in Texas, Louisiana, and Mississippi

(Hunter & Pierce, 1912). S. (D.) molesta validiuscula Emery was often

found attacking codling moth larvae under experimental tree bands in

West Virginia apple orchards (Jenne, 1909).


Biology and Ecology

Because Diplorhoptrum species are still in considerable taxonomic

flux, there are few published reports relating to the biology and ecology

of the species. The bulk of information concerns microhabitat and eco-

system distributions. In Table 1 (Appendix), data on nesting locations

of S. (D.) molesta is presented. Although this species seems able to

establish colonies in most types of habitats, on the microhabitat level

it displays a distinct preference for cover, particularly stones.

What is known concerning the biology of Diplorhoptrum species

consists of observations dispersed through the general literature on

ants with almost no exhaustive studies. For example, in at least one

western state (Utah) S. (D.) molesta validiuscula is considered a

dominant Diplorhoptrum species, is 1.3 mm long, lives under stones,

bark, and logs (Cole, 1942), and has been observed feeding on chicks,

rats, and mice (Eckert & Mallis, 1937). Hayes (1920) has conducted the

only biological study of S. (D.) molesta. His thorough study determined

life tables for the brood, field colony size, queen egg production,

flight information, and methods of laboratory colony maintenance.

One of the most interesting habits of S. (D.) molesta, as well as

other Diplorhoptrum species, is lestobiosis. This ant has been found






9


living beside or with 33 different species of ants of four subfamilies

(Cook, 1953; Hayes, 1920; King, 1896, 1901a & b; Mallis, 1941; Mann,

1911a; and Wheeler, 1901). S. (D.) molesta will also live amicably with

the termite Reticulitermes flavipes (Kollar) in the laboratory (Smythe &

Coppel, 1973). The data on Diplorhoptrum species which are freeliving

or lestobiotic are lacking, spotty, or contradictory. While Kennedy

(1938) found four nests of S. (D.) texana, all lestobiotic, Wheeler and

Wheeler (1963) made 81 collections of which 53 were independent nests.

They were unable to determine if the ants were S. (D.) molesta or

S. (D.) molesta validiuscula. They found that the independent nests

had " dia. chambers as much as 5" below the soil surface, but mostly

in the upper 2Y". As Wheeler (1901) pointed out, however, there could

be long connecting galleries between these species and their suspected

host galleries or no relationship at all.

Diplorhoptrum are themselves hosts of a number of guests. Wheeler

discovered the first guest, reported only as a Hymenopteran (Brues,

1903). Fall (1920) found a new species of blind beetle Alaudes alternata

Fall in S. (D.) molesta nests. King (1895, 1897) observed a mite on

larvae which attached midway between the thorax and abdomen and a

Staphylinid of the tribe Aleocharini. Schwarz (1890a & b, 1896) found

Coleoptera of the genera Lithocharis and Myrmecochara with S. (D.)

molesta, but believed the former to be an accidental guest. Wickham

found the latter beetle with the ants, first calling it Gyrophaena sp.

but later correcting the name (1892, 1894) to Myrmecochara crinita

Casey. He felt this species to be a true myrmecophile along with

Atheta exilissima Casey. Wing (1951) found a number of wasp guests of

the genera Buresopria and Auxopaedeutes, and Loxotropa californica

Ashmead.





10


S. (D.) molesta appears to have few natural enemies, although

research lags in this area. Beal (1911, 1912) found that a flicker,

Colaptes auratus L. subsp., and the kingbird or bee martin, Tyrannus

tyrannus (L.) feed on S. (D.) molesta. No less than 39 species of birds

were observed feeding on a mating flight of S. (D.) molesta (Judd,

1901). Diplorhoptrum probably have a number of ant enemies, but only

two are reported: Hung (1974) found that 10% (or 80) of the ants'

heads in the garbage pile of a Conomyrma nest were those of S. (0.)

molesta. Buren et al. (1977) suggest false phragmosis evolved by

Pheidole lamia Wheeler serves as a defensive tactic against subterranean

ants, mainly Diplorhoptrum.

It is fortunate that two astute observers have published their

observations on the mating flights of S. (D.) molesta. In Kansas,

Hayes (1925) observed a flight at 5 p.m. on July 27, 1920, which con-

tinued until dusk, and a flight July 5, 1921. Both were preceded by

heavy rain. He noted that mating occurred in the air, that females

outnumbered males (unusual in ants), and that males mated more than

once. Farther north in Canada, late August flights occurred

(Macnamara, 1945; Wheeler, 1916) and Macnamara observed a dense evening

swarm, 3-4 ft in diam. and at its lowest point about 3 ft off the

ground. He saw that the swarm was sluggish and noticed, most impor-

tantly, that the females were carrying workers on their bodies. Wing

(1951) reported that W. L. Brown found approximately 20% of the S. (D.)

molesta females in a Philadelphia flight had one or rarely two workers
attached to their legs.








Venom Chemistry

Venom chemistry and behavior associated with it have attracted

increasing interest and research in the past decade. Jones et al. (1979)
identified a new venomous constituent in the poison gland of S. (D.)

molesta and S. (D.) texana. The chemical, 2-hexyl-5-pentyl-pyrrolidine,

is the first known 2,5-dialkyl pyrrolidine from a natural source.

More recently, a new alkaloid, (5Z,8E)-3-heptyl-5-methyl pyrrolizidine

has been identified (Jones et al., in press) in S. (D.) xenovenenum

n.sp. denoted as a species near S. (D.) tennesseensis. Wilson (1975)

studied Pheidole dentata Mayr and found a chemical alarm-recruitment

system in the minor caste which recruits the majors. It is a chemical

which specifically recruits the majors to ants of the genus Solenopsis.

Holldobler (1973) reported that S. (D.) fugax (Latreille) (European

species) has a recruitment pheromone produced by the Dufour gland and a

repellent substance produced by the poison gland. The repellent pre-

vents brood-keeping ants from defending their own larvae against the

Diplorhoptrum. Blum and Jones (1980) found that the S. (D.) fugax

substance repelled 18 species of ants. The secretion of one gland

would stop Lasius flavus McCook from using a nest entrance for almost

an hour. The main component was trans-2-butyl-5-heptylpyrrolidine, a

dialkyl-pyrrolidine which is evidently an integral part of S. (D.)

fugax raiding strategy.














MATERIALS AND METHODS


Taxonomy


Because the largest Florida S. (Diplorhoptrum) worker is only

1.8 mm long, it is imperative that anyone wishing to study this group

have at their disposal a microscope with a minimum of 40 diameters of

magnification. The Wild microscope used for this study was also

equipped with an ocular micrometer.

Traditional measurement techniques were utilized and specimens

were compared with types at the U.S. Natural History Museum in

Washington, D.C., and the Museum of Comparative Zoology at Harvard

University, Cambridge, Mass. Measurements of specimens and indexes

calculated were as follows:

1. Head width: greatest width of the head in full face view.

2. Head length: greatest length of the head in full face

view, but excluding the mandibles.
3. Head index: Head width x 100
3. Head index: Head length
Head length
4. Head depth: measured on line running through the eye and

perpendicular to line running from just above mandibular

insertion to point where neck meets thorax.

5. Thoracic length: greatest length of thorax in lateral view.

6. Scape length: middle of antennal socket to tip of scape.
7. Scape index: Scape length x 100
Head length
8. Funiculus length: tip of scape to tip of funicular club.

12






13


9. Club length: length of last 2 antennal segments which

form the typical club.

10. Body length: total length of specimen from mandibles to

tip of the gaster. This measurement cannot be made as

accurately as the others. Specimens were so rarely in a

natural position on the pins that only a rough estimate

was made of total body lengths.

11. Eye length: greatest length of the eye.

12. Eye index: Eye length x 100
Head length

Specimens studied were obtained from as many locations as possible

in Florida. Series collected by D. P. Wojcik (USDA, Gainesville,

Florida) and by A. F. Van Pelt (collections in the Florida State

Collection of Arthropods, Gainesville, Florida) and Dr. William F.

Buren (Dept. of Entomology and Nematology, Univ. of Florida, Gainesville,

Florida) were studied.


Lactophenol Fixation


A novel method for taxonomic study of ants was use of slide-

mounted specimens prepared by a four minute lactophenol fixation pro-

cess (Esser, 1973) initially developed for nematode studies. This

rapid procedure cleared specimens and allowed particularly detailed

study of pubescence.

1. The ants were removed from alcohol and placed in water in a

watch glass set inside a petri dish on a hot plate.

2. The specimens were heated to 3700C and lactophenol added

until the watch glass was full.






14


3. The specimens were heated an additional two minutes

then were cooled 10 minutes.

4. A ring of "zut" (Thorn, 1935), a sealant used to mount

helminths, is placed on a slide. The ring is built up

enough to avoid crushing the specimens (and requires practice

and extra specimens). The ants, in some lactophenol

solution, are placed in the ring and a cover slip placed

over the ants and the zut.

Having a number of ants per slide ensured that at least one would be

positioned correctly for any structure studied.


Scanning Electron Micrography


Diplorhoptrum workers are so small that use of the usual black

carbon contact cement was nearly impossible. Split-second timing was

needed, otherwise the cement dried or the specimen disappeared under

the cement.

These problems were overcome by the use of double-stick white

labels. The ants were arranged on the label and pushed into the ad-

hesive. But a problem developed with charging (a process which results

in bright light bouncing off the specimen and obscuring structure),

even though the specimens had been double-gold-coated at three minutes

per coat with a break between coatings to dissipate heat.

To alleviate charging, the ants were placed on the sticky labels

and spots of carbon glue were placed near the specimens and smeared

into contact with the tarsi or under parts of the body. In this way

conduction was increased and charging reduced.






15


Field Studies

Collecting Techniques

Unlike many terrestrial ant species, Diplorhoptrum have few

surface indications of nest location, with the exception of S. (D.)

pergandei mating flight tumuli (Figure 29). Diplorhoptrum are

nocturnal and, even at night, forage little above ground except in

moist areas. As a result, conventional methods were not as effective

in locating and collecting these ants; however, the following

techniques were utilized with some success:

1. Lifting bark from bases of trees and from rotten logs.

Species most frequently obtained were S. (D.) pergandei and S. (D.)

carolinensis.

2. Searching for unnatural soil disturbances such as slight

mounds and color changes indicating excavations, or for parts of dead

insects grouped in one place.

3. Overtuniing stones, logs, and other soil cover and tearing

apart rotten logs.

4. Searching shovelfuls of soil for foragers, particularly in

moist areas and along the edges of tree roots. Although this method

would seem time consuming and the finding of any ants a matter of

chance, it was one of the most effective. One morning's work and

nearly 200 shovelfuls produced one S. (D.) carolinensis queen and

workers and an additional sample of workers; a second morning's work

produced one S. (D.) pergandei queen and colony. In a third area one

half hour of work produced two S. (D.) carolinensis queens and colones.






16


These collections were in different habitats, the first two areas

were xeric while the third area was hydric.


Naves Traps


Naves traps (unpublished technique) were baited with honey agar

(Bhatkar and Whitcomb, 1970), cabbage loopers, Diaprepes beetle larvae,

Fire Ant queens (S. invicta), or most often tunafish. The Naves trap

is made by modifying a two ml sidetabbed Dispobeaker (Scientific

Products) as follows: A teasing needle is heated and used to melt

0.5-0.9 mm diam. holes in the cap and bottom of the beaker. Three

holes are placed in the cap top, six around the sides of the cap and

three in the bottom of the trap body. All attempts to further

standardize hole size by wiring a soldering iron with 1/16 inch

copper wire failed; the wire would not hold enough heat to melt the

plastic. Acrylic red yarn tied around the trap under the side tabs

served as a marker and means of pulling the trap from the ground.

A narrow bladed trowel (5 cm at greatest width) was used to

bury the traps with their bases at a depth of 14 cm. It was found that

less than 10 cm depths resulted in traps filled with fine sand which

sifted through the trap tops in dry soils. Depths of 18 cm or more

made trap recovery and replacement of the soil difficult. The 14 cm

depth was chosen as an average and employed throughout trapping ex-

periments as an experimental constant.

As a note of caution, even the small holes of these traps did not

exclude a number of other ant species: Pheidole metallescens Emery,

Brachymyrmex depilis Emery, Pheidole dentata Mayr, and P. floridana

Emery. Other less frequent species were Ponera pennsylvanica Buckley






17


and a Strumigenys species. In areas infested with S. invicta, the

fire ants chewed at the cap holes until they were large enough to gain

entrance to the bait. Their chewing habit cost me considerable time

in the making of new caps.

Unfortunately, the Dispobeakers have been discontinued by the

manufacturer. Traps have now been made from plastic, cap-attached

vials made by Bio-Rad Company. These traps will be utilized in South

America studies in the near future but are still in the experimental

stage.


Local Distribution Study

Studies of small area distribution of Diplorhoptrum species were

undertaken utilizing stratified sampling. A 5 x 10 square meter grid

was laid out in a open field at the Gainesville Airport. The field is

mowed twice a year, maintaining grasses and occasional young turkey

oaks (quercus laevis Walt.) below 3-4 ft. The area is designated for

use only as an emergency runway. A second 5 x 10 square meter grid was

laid out in a long leaf pine (Pinus palustris Mill.)--turkey oak woods

bordering the northeast side of the open field.

Biweekly (June 1979-July 1979) and then bimonthly (Aug. 1979-

June 1980) Naves traps were loaded with tunafish and placed one in

the center of each square meter of the grids. The traps were placed

at a depth of 14 cm for 24 hours. At the end of 24 hours the traps were

taken up. Traps with ants were quickly placed in snap-top vials for

later indentification. The square meter was rebaited with another trap.

Following 24 hours, the traps were again taken up, positive traps






18


put in vials, and red marker yarn placed in the soil to mark the bait

station until it was rebaited.


Use of Light Trap Collections


During May through August, Diplorhoptrum males and females of

S. (D.) pergandei, S. (D.) carolinensis, and rarely S. (D.) reinerti

are attracted to light traps. Larger collections of S. (D.)

carolinensis can be made with a light trap and a white sheet than

with a conventional, walk-in light trap. The reason for this is

unknown, but possibly a different quality of ultraviolet light is

reflected by the sheet, and thus attracts this species.


Laboratory Studies


Colony Nest Materials


Maintaining Diplorhoptrum colonies in the laboratory is extremely

difficult. Their small size and hypogaeic habits make them highly

vulnerable to d#siccation. Workers of colonies in open laboratory pans

at 80% relative humidity die within 24 hours. If a colony is presented

with a moist chamber within an open laboratory pan, the workers which

forage outside the chamber will die in the open pan before they find

their way back to the colony. The colony dies by slow loss of

foraging workers.

Florida Diplorhoptrum species seem to need humidity levels of

nearly 100%, in contrast to S. (D.) molesta, and other Diplorhoptrum

species such as the unidentified Peruvian species in Dr. Ed Wilson's

laboratory at Harvard University. This species is kept in a plastic

box open to the air. Lower humidity requirements apparently allow





19


S. (D.) molesta and S. (D.) texana to forage above ground during the
day. S. (D.) texana was observed in a late morning expedition to food

in a car trunk (July, 1980) at Clinton, Iowa (pers. comm., Dr. W. F.

Buren) while I have taken S. (D.) texana at honey baits in full sun

(June, 1980) at Cedar Falls, Iowa.

Two materials often used to maintain ant nest humidity are plaster

of paris and Castone When colonies were placed in petri dishes with

floors of either compound, workers began to go into convulsions within

a few hours, then died. An entire S. (D.) carolinensis colony died

overnight June 3, 1980, while a S. (D.) pergandei colony displayed

similar symptoms the following day. The queen died two days after

exposure to these compounds, or possibly because of shock due to colony

loss. Neither species queen showed convulsive symptoms.

Colony nest humidity was finally maintained by 1) moistened cotton

floors, or 2) by using "aged" plaster of paris covering only one fourth

of the nest floor. The aged plaster was in old petri dish nests which

had been used and repeatedly washed in hot, soapy water.

The small size of the Diplorhoptrum workers allows them to escape

from any kind of petri dish. Talc and Fluon could not be used because

of the high humidity levels. When colonies were sealed in with artist's

clay, the workers gnawed.0.82 mm holes through the clay and escaped.

In colonies sealed with vaseline, many workers died overnight, ap-

parently from fumes given off by this material. Finally the vegetable

fat Crisco was tried. The ants refused to cross the greasy barrier.

Crisco was subsequently placed around the inside rims of petri dishes

effectively preventing ant escapes.





20


When an Iowa S. (D.) molesta colony was placed in a Crisco

barriered nest, however, the workers began to eat the Crisco --some-

thing none of the Florida species had done! The colony is presently

housed in a glass jar with a screw-top lid.

Feeding


Colonies offered a selection of foods including 1:1 honey-water,

butter, raw hamburger, peanut butter, honey-agar, oil-packed tunafish,

fire ant diet (used by USDA, Fire Ant Laboratory, Gainesville, Florida),

and mealworms. S. (D.) carolinensis fed upon the honey-agar and tuna-

fish, but largely ignored the other foods. They backed off hurriedly

from peanut butter. Mealworm larvae were killed, but did not appear to

be fed upon.

Although S. (D.) picta and S. (D.) reinerti accepted fire ant diet

and honey-agar readily, colonies of S. (D.) pergandei were reluctant

feeders on all offered foods. Fire ant larvae were also offered to

this species but were refused, even when the larvae were punctured so

that haemolymph exuded. Colonies of this species could not be main-

tained for more than a few months.

Queen Colony Founding

Young, newly mated females obtained from light traps were ini-

tially placed in compartmented plastic boxes. Each compartment had a

moistened plaster of paris floor and sides painted with Fluon The

high humidity allowed the queens to walk over the Fluon however,

and they congregated in groups. Of 36 S. (D.) carolinensis, 45 S. (D.)

pergandei and two S. (D.) reinerti females, eight S. (D.) carolinensis

no S. (D.) pergandei and both S. (D.) reinerti queens reared brood to






21


the worker stage. No S. (D.) pergandei queen was able to found a

colony. Some queens laid eggs and had larvae, but died before workers

were reared.

Other materials and methods were then tried:

1. Glass tubes with moistened cotton.

2. Aged plaster of paris bottomed vials with soil above the

plaster and black paper for cover.

3. Cores of grass sod placed in vials, allowing excavation and a

more natural environment.

4. Placement in queenless laboratory colonies.

Methods 1-3 were unsuccessful. Method 4--addition of queens to

queenless colonies--ended inconclusively. The females were initially

seized by the legs and antennae, but subsequently were released and

allowed to stand over the brood. Of 12 females added, six had died

before the colony had to be left unattended for two weeks. The colony

died during that time.

In summary, no satisfactory method was found for inducing queen

colony foundation in S. (D.) pergandei. Presenting young queens with

brood or callows of their species will probably prove to be the

most useful method.

Queens of S. (D.) carolinensis found colonies readily in plaster

of paris cups if they are allowed to remain together in groups. Queens

of S. (D.) reinerti founded colonies easily alone. It was, in fact,

the unexpected yellow workers reared by these black queens that first

convinced me that they were a new species.














RESULTS


Section I
A Taxonomic Review of the S. (Diplorhoptrum) of Florida


Introduction


No taxonomic progress has been made in the Solenopsis (Diplorhoptrum)

group for a number of years. The most recent species to be described

was S. (D.) longiceps by M. R. Smith in 1942. This species name was

subsequently found to be preoccupied by Solenopsis longiceps Forel, and

was changed to S. (D.) tennesseensis M. R. Smith in 1951. The most

recent taxonomic key for the group is that by Creighton (1950) in which

he tried to define the group and synonymized several names.

Because of taxonomic and identification difficulties, most workers

have been lumping any Diplorhoptrum specimen under S. (D.) molesta.

This species, in fact, is supposed to occur in Florida, but I have not

collected it anywhere in the state. The situation is not improved by

the fact that all of Say's types, including those of S. (D.) molesta

(Say), have been lost.

When a small, 100-meter square area in Gainesville was sampled and

three new species were frequently recovered, it was very apparent that

taxonomic work was needed. This study will help to prevent the "band-

wagon" effect, which has gone on for many years, of labeling any

Diplorhoptrum specimen molesta. It will fill the gap left by Van

Pelt (1947) who purposely omitted the group from his Florida key

because of their uncertain taxonomy.
22





23

The four new species found during this study have the proposed

names of S. (D.) "abdita" n.sp., S. (D.) "nickersoni" n.sp., S. (D.)

"reinerti" n.sp. and S. (D.) "xenovenenum" n.sp. (Names proposed here

in quotation marks are not to be considered validly or effectively

published for nomenclatural purposes.)






24


Key to S. (Diplorhoptrum) Species of Florida


la) Mesopropodeal constriction strong (Fig. 21); promesonotum and

propodeum, in profile, strongly convex; petiolar node placed

somewhat anterior to the petiolar-postpetiolar juncture (Fig. 23)

so that the petiole has a distinct slender posterior portion;

color uniformly dark brown or black including the appendages; an

arboreal ant found nesting in twigs and small branches of

various trees . . . . . . . . . .. picta Emery

b) Lacking above combination of characters; mesopropodeal constric-

tion not as strong; promesonotum and propodeum never both strongly

convex; petiolar node placed near the petiolar-postpetiolar

juncture; color usually pale yellow, or if dark, then the ap-

pendages are pale; subterranean (except for one rare yellow

arboreal species). . . . . . . . . . . 2

2a) Head, thorax, and gaster dark brown with pale brown or pale

yellow appendages; eyes of medium size for this group of species;

with 2, occasionally 3 facets; subterranean. . nickersoni n.sp.

b) Usually entirely pale yellow to somewhat darker yellow; one

species (carolinensis) with moderate infuscations of brown on

head and gaster. . . . . . . . . . . .... 3

3a) Dense pilosity on head and usually on promesonotum arising from

large, obvious punctures; eyes small or weakly pigmented or

both . . . . . .... . . . . . . . 4

b) Pilosity not arising from large, obvious punctures and not

noticeably dense; eyes larger or at least pigmented, the facets

surrounded by a black matrix. ... . . . . . .. 7






25


4a) Thorax in profile straight above; base and declivity of pro-

podeum distinguishable; head narrow and elongate, head index

79; punctures on head over entire surface, no median streak

free of punctures and hairs. . . .*tennesseensis M. R. Smith

b) Head proportionately not as narrow; head in some species with

distinct median streak free of punctures and hairs; propodeum

usually evenly rounded in profile and without distinguishable

base and declivity . . . . . . . . . . . 5

5a) Head with obvious median streak free of punctures and hairs

(Fig. 2), in mounted specimens a median crease may also be

present in this area (but this is not evident in living or

freshly killed specimens); head elongate and narrow, head

index 89; females and males dark brown or black; head of female

trapezoidal in shape . . . . . . .. .. abdita n.sp.

b) Without this combination of characters; head either without

median hair-free streak, or head nearly as broad as long; head

never with median crease in mounted specimens; males and females

either light yellow or, if black, then head of female not

trapezoidal in shape . . . . . . . . ... . . 6

6a) Large species 1.8 mm in total length with head 0.429 0.009 mm

in length; head index 96; head thick and robust in profile;

shaped as in Fig. 18; males and females yellow or light

brownish yellow; wings clear and nearly colorless . . . .

. . . . . . . . . . pergandei Forel

b) Small species 1.1 mm in total length; head 0.318 0.002 mm in

length, head index 77; head flattened above and slender in






26


profile; males and females dark brown to black; wings heavily

and entirely infuscated with dark brown. ... xenovenenum n. sp.

7a) Dorsal surfaces of head with moderately numerous hairs nearly

entirely of the same short length (Figs. 6, 26) . . ... .8

b) Dorsal surfaces with sparser hairs, these distinctly uneven

in length (Fig. 10). . . . . . . . . . . .9

8a) Rear of head and anterior portion of gaster lightly to moderately

infuscated with brown; eyes with 3 or 4 facets; females yellow-

ish to light yellowish brown; female eyes very large, eye

index 41. ..... . . . . . carolinensis Forel

b) Head and gaster without infuscation; uniformly pale yellow,

some specimens nearly whitish; eyes with 2 facets; females dark

brown to black; female eyes small, eye index 33. . reinerti n.sp.

9a) Comparatively large size; body length 1.58 mm; head length

0.491 0.004mm; head and gaster usually weakly infuscated;

subterranean .. . . . . .. . . . *texana Emery

b) Small size, body length 1.34 mm; head length 0.363 0.003 mm;

entirely light brownish yellow without trace of infuscation

on any areas; arboreal . . . . . . .. corticalis Forel












*S.(D.) tennesseensis and S. (D.) texana were not found in Florida in
the present study, and previous records seem doubtful. It is
possible that these species will eventually be found in Florida.






27


1. Solenopsis (Diplorhoptrum) abdita n.sp.


Diagnosis:


Workers pale colored, and densely covered with short hairs. Head

strongly marked with prominent punctures but with a clear median streak

free of piligerous punctures. Eyes reduced to one facet, inconspicuous.

Head broader in proportion to length than in tennesseensis, and thorax

more convex in profile. Females large and dark colored, the head

uniquely trapezoidal in shape. Wings colorless. Head and thorax with

numerous piligerous punctures.


Description:


Worker:


Measurements: Head length 0.361 0.004 mm; head width

0.32 0.002 mm, head index 89, scape length 0.235 0.003 mm,

scape index 65. Thorax length 0.444 0.003 mm, total body

length 1.56 mm. The preceding measurements based on nine

specimens.

Structural Characters: Head longer than wide, rectanguloid

with faintly convex sides, the posterior border slightly excised

in the center. In some specimens the head is slightly more

narrow anteriorly. The eyes reduced to a single facet. Ventral

border of head moderately convex in profile. Anterior edge of

clypeus widely and angularly separated from dorsal surface of

mandible in profile. A flat head (Fig. 25) not present.

Promesonotum of thorax weakly convex in profile, propodeal

base somewhat more convex. Petiole large in profile with a






28


prominent anterioventral tooth and prominent ventral swelling

(Fig. 27). From above, petiole and postpetiole nearly equal in

width. Postpetiole with rounded sides as seen from above, not

trapezoidal. Anterioventral flange of postpetiole seen in

profile sharp but very small.

Sculpture: All surfaces smooth and shining except for head

which is heavily and densely marked with prominent punctures and

dorsum of the promesonotum which is moderately marked with weaker

punctures. Head has characteristic median streak free of punc-

tures.

Pilosity: Head with numerous short hairs. Thorax, petiole,

postpetiole, legs, and gaster also with numerous short hairs

which may be longer than those on the head (Fig. 1).

Color: Entirely light yellow to light yellowish brown.


Female:


Diagnosis: A rather large, dark colored female with

colorless wings. Head distinctly trapezoidal in shape. Head

and dorsum of thorax covered with numerous strong piligerous

punctures. Differs markedly from S. (D.) pergandei females in

color and head shape.

Description: Head length 0.78 mm, head with 0.98 mm, head

index 126, scape length 0.67 mm, scape index 86, eye length 0.24 mm,

body length 5.5 mm.

Structural Characters: Head distinctly trapezoidal, with

nearly straight hind border and sides, the head distinctly more

narrow in front than behind. Scapes not quite reaching hind






29


corners of the head. Eyes rather small for Diplorhoptrum females.

Ocelli also small for females of this group. Petiole with blunt

node, slightly excised above as seen from behind. Postpetiole

wider than petiole, trapezoidal as seen from above, wider

posteriorly than anteriorly.

Pilosity: Head and thorax with numerous hairs arising from

strong punctures. Gastric pilosity also abundant but not arising

from punctures. A median streak on head free from punctures or

hairs as in the worker.

Color: Head, thorax, petiole, postpetiole and gaster dark

brown. Legs and antennae light greyish yellow. Wings colorless.

Male: Unknown


Types:


Holotype--a worker from Gainesville, Florida, captured with a

Naves trap (June 16, 1979). Airport area. C. R. Thompson

Paratypes--numerous specimens from Gainesville Airport area, June

through September, 1979, C. R. Thompson; three workers and one female

from Tall Timbers Research Station, Florida. June, 1975. M. A. Naves.

The holotype and several paratypes will be deposited at the

Museum of Comparative Zoology. Paratypes will also be deposited in

the Florida State Collection of Arthropods, Gainesville, Florida.


Discussion:


This species appears superficially close to pergandei on one hand

and to tennesseensis on the other. The female, dark in color and with






30


a unique head shape, shows that the species is not close to pergandei.

The punctures on the head are stronger even than in pergandei, and the

clear median streak on the head free of punctures seems to be a constant

character which does not occur in tennesseensis. The head is narrower

in proportion to length than in pergandei but is noticeably wider than

in tennesseensis. The dorsum of the thorax is more flattened in

tennesseensis than in abdita. Scape and funiculus length shorter in

abdita than in pergandei.

This species has been found at Gainesville and Tall Timbers

Research Station north of Tallahassee. It was relatively common in

the test area near Gainesville although not as abundant as

carolinensis. The species may not be rare,but merely previously

overlooked and/or unrecognized.






31

2. Solenopsis (Diplorhoptrum) carolinensis Forel


Solenopsis texana race carolinensis Forel 1901. Ann. Soc.
Entomol. Belg. 45:345.

Solenopsis (Diplorhoptrum) carolinensis Forel. Creighton, 1950.
Bull. Mus. Comp. Zool. 104:236.

Type locality: Faisons, North Carolina

Types: Museum of Comparative Zoology, Harvard University

Range: North Carolina and Tennessee north to lower New England states


Diagnosis:


A small Diplorhoptrum with a quadrate-shaped head, moderately

sized darkly pigmented eyes. Pilosity moderate, piligerous punctures

weak. Pilosity on the head short and nearly all of the same length.

In profile, often with an anterioventral tooth on the petiole. Head

and gaster usually infuscated. Female small with large eyes.


Discussion:


Described as a characteristic species of North Carolina (Wheeler,

1904b) S. (D.) carolinensis is also a common species in Florida. It is

very common in Gainesville, and was found wherever the Diplorhoptrum

fauna was sampled throughout the state. It was found in many

habitats: palmetto thickets, turkey oak, open sand areas, rocky soil

in Homestead, grassy areas, and pine woods.

The nests of this species are shallow (less than 20 cm) and

quite frequently one turn with a shovel will bring up the colony queen

with a small group of brood and workers. A colony can have more than

one queen. This species tends to forage more than most other Florida






32


species in the forest duff, and I have seen it tending mealy bugs.

Excavations of an S. (D.) pergandei colony will often bring

S. (D.) carolinensis to light in the same shovelfull. The larvae of

S. (D.) carolinensis have a pinkish cast and are smaller than those of

S. (D.) pergandei.

The mating flights of this species have not been observed, but I

have dug sexual brood in June (6/9/79) and the flights occur during the
same months (June through August) as those of S. (D.) pergandei. The

sexuals of S. (D.) carolinensis are attracted to light traps, but in

smaller numbers than S. (D.) pergandei. The sexuals of S. (D.)

carolinensis fly earlier in the morning (5-5:30 a.m.).

I suspect that the Florida S. (D.) molesta records, and one of

S. (D.) laeviceps (Smith, 1930), are based on misidentified specimens

of S. (D.) carolinensis. Types of this species at the Museum of

Comparative Zoology have been examined by Dr. William F. Buren.






33


3. Solenopsis (Diplorhoptrum) corticalis Forel


Solenopsis corticalis Forel, 1904. Ann. Soc. Entomol. Belg.
48:172.

Type locality: Cuba

Types: Museum d' Histoire Naturelle, Geneva, Switzerland. None in this
country

Range: West Indies (Wheeler, 1913; Wolcott, 1948) and southern Florida


Diagnosis:


Small arboreal species. Head is rectangular and the eyes are

large in comparison with other species of the group. Petiole has

anterioventral tooth. Hairs are rather sparse, of uneven lengths and

do not arise from punctures. The integument is highly shining. Color

is yellow or light brownish-yellow, usually without trace of infuscation.


Discussion:


This is one of the two known arboreal Diplorhoptrum in Florida,

but appears to be much rarer than picta and is yellowish whereas picta

is black to dark reddish-brown.

Prior to this study, S. (D.) corticalis had not been reported from

Florida. A series of this species was taken near Manalapan, a coastal

town south of Palm Beach in November, 1945, by Dr. William F. Buren.

It was found in branches of red mangrove (Rhizophora mangle L.). It was

subsequently rediscovered by Dr. J. C. Nickerson in the same habitat

in May, 1980, on Park Key. This species is polygynous and is probably

nocturnal, as no foragers were seen in the daylight. Specimens from the

Manalapan series have been compared with West Indian material at the

Museum of Comparative Zoology by Dr. William F. Buren.





34


4. Solenopsis (Diplorhoptrum) molesta (Say)


Myrmica molesta Say, 1836. Boston J. Natur. Hist. 1:293.

Myrmica minuta Say, 1836. Boston J. Natur. Hist. 1:293.

Myrmica (Tetmamorium) exigua Buckley, 1867. Proc. Entomol.
Soc. Philadelphia 6:342-3.

Solenopsis debilis Mayr, 1886. Zool.-Bot. Gesell. Wien, Verh.
36:461.

Solenopsis molesta var. validiuscula Emery, 1895. Zool. Jahrb.,
Abt. f. System. 8:278.

Solenopsis (Diplorhoptrum) molesta (Say), Creighton, 1950.
Bull. Mus. Comp. Zool. 104:237.

Type locality: Indiana

Types: No longer in existence

Range: Reported from east and central U.S. from the Gulf States to
Canada. Supposedly rare in the southern areas of the Gulf
States.



Diagnosis:


Head and thorax robust, broad in relation to length. In profile

the petiole considerably larger than the postpetiole, but seen from

above the postpetiole much wider than the petiole. Differs from

carolinensis and texana in having a distinctly broader thorax. Hairs

are sparse and of mixed lengths. No obvious piligerous punctures.


Discussion:


It is this species name which has been most abused in the litera-

ture. Authors are legion (Browne and Gregg, 1969; Mann, 1911; Robbins,

1910; Rees and Grundmann, 1940; Talbot, 1975; Yensen and Clark, 1977)

who list this ant, but give little or no additional information. For






35


Florida, S. (D.) molesta is reported from Rockdale, in Dade County,

(Nielsson et al., 1971) where it was tending Aphis coreopsidis

(Thomas), but no further information on the biology is given. Van Pelt

(1958) reports this species from Welaka Reserve and observed the ants

closely. He noted that what he was tentatively calling molesta did

not match specimens he had seen. Van Pelt was one of the few authors

(Mitchell and Pierce, 1912; Ross et al., 1971; Huddleston and Fluker,

1968 were others) who qualified their identifications and noted the

existing taxonomic confusion.

At this time I have found no specimens of S. (D.) molesta in

Florida, nor have I seen any in other Florida collections. Van Pelt's

specimens are S. (D.) carolinensis.





36


5. Solenopsis (Diplorhoptrum) nickersoni n.sp.


Diagnosis:


A small dark species similar to S. (D.) carolinensis in head

shape, eye characteristics, thorax, and petiole shape. Antennae and

legs pale-colored and strongly contrasting with body color.


Description:


Worker:


Measurements: Head length 0.345 0.003 mm, head width

0.30 0.002 mm, head index 86, scape length 0.241 0.003,

scape index 70, funiculus length 0.359 0.004 mm, club

length 0.222 0.002 mm. Thorax length 0.384 0.004 mm,

body length 1.2 mm. The preceding measurements based on 18

specimens.

Structural characters: Head longer than broad (Fig. 14),

rectanguloid, with weakly convex sides and straight posterior

border. Head in profile with a narrow angle between the

clypeus and mandibles. Head in profile moderately flattened.

Eyes dark in color with 2-3 facets, similar to carolinensis.

Thorax in profile (Fig. 13) with moderate meso-propodeal

suture, the dorsal outline similar to carolinensis. Petiole in

profile similar to carolinensis (Fig. 7). Petiole usually

without anterioventral teeth. From above, node of petiole a

little narrower than postpetiole. Postpetiole with trapezoidal

shape as in carolinensis. In profile postpetiole with sharp

anterioventral flange (Fig. 15).





37


Sculpture: All surfaces smooth and shining. Piligerous

punctures on dorsum of head weak and not noticeably interrupting

the surface.

Pilosity: Head with rather short, sparse hairs. Thorax

with longer hairs in moderate numbers. Gaster also moderately

beset with hairs.

Color: The head, thorax, petiole, postpetiole, and gaster

dark brown; antennae and legs, including coxae, very pale brown,

almost whitish.


Female: Unknown?


Male: Unknown?


The purported females and males of nickersoni thus far have not

been found with workers. A match was made by a process of

elimination. All other dark colored females and males occurring

in Florida have been found with conspecific workers. The dark

bodies of nickersoni contrasting with the pale colored appen-

dages is a characteristic found in both the workers and the

purported females and males, but descriptions await a collection

of sexuals with workers.


Types:


Holotype--a worker from Gainesville, Florida, caught in a Naves

trap on June 16, 1979. Paratype material comprises numerous workers

collected in Gainesville, Ocala, and Apopka, Florida on various dates

with Naves traps. All were collected by C. R. Thompson.




38


The holotype and several paratypes will be deposited at the

Museum of Comparative Zoology. Paratypes will also be deposited in

the Florida State Collection of Arthropods, Gainesville, Florida.

This species is named in honor of Dr. J. C. Nickerson, Division

of Plant Industry, Gainesville, Florida. Dr. Nickerson, over a period

of several years, has greatly aided and encouraged me in my

myrmecological studies.


Discussion:


S. (D.) nickersoni is readily distinguished from all other Florida
ants of this genus by its dark color which contrasts with the light

color of its antennae and legs. In structure it is similar to

carolinensis including head shape, eye prominence, thoracic shape, and

petiole and postpetiole shape. It lacks the prominent head punctures

which are typical of pergandei, abdita, and xenovenenum n.sp.

This species has been found in Florida at Gainesville, Ocala,

Apopka and .Myakka State Park. The species, from data collected in

1979 at Gainesville, appeared to be rare. It was caught in only one

area and in one trap position out of 100. In 1980, however, it has

been taken in April and June at nine trap locations in both open

field and wooded areas.

The venom of this species has not been analyzed.

In two instances, workers of nickersoni were attracted to a

second (or third) larval instar of Diaprepes abbreviatus (L.), the

Sugar Cane Rootstalk Borer, in a Naves trap, and were able to kill and

dismember the weevil larva. This occurred on May 13 and June 9, 1980,

near Plymouth, Florida, in a wooded area probably relatively free from






39


insecticides. S. (D.) nickersoni was not found in any citrus grove

area near Apopka or Orlando which had been treated by insecticides or

herbicides.





40


6. Solenopsis (Diplorhoptrum) pergandei Forel


Solenopsis pergandei Forel, 1901. Ann. Soc. Entomol. Belg.
45:343.

Solenopsis (Diplorhoptrum) pergandei Forel. M. E. Smith, 1947.
Amer. Mid. Natur. 37:568.

Solenopsis (Diplorhoptrum) pergandei Forel. Creighton, 1950.
Bull. Mus. Comp. Zool. 104:237.

Type locality: Faisons, North Carolina.

Types: Museum d' Histoire Naturelle, Geneva, Switzerland. None in this
country

Range: Virginia and south to Florida, west to Louisiana.


Diagnosis:


This clear-yellow Diplorhoptrum is the largest species of this

subgenus in Florida. The worker is approximately 1.8 mm long while

the large females are 5.5 mm long. It also differs from other Florida

species in its robust head and thorax. Piligerous punctures on

head numerous and distinct. Head quadrate, only a little longer

than broad, convex dorso-ventrally in profile.


Discussion:


This species is common in Florida, and was found over the entire

state. It does not leave any surface indication of its nests except

during May through August in Florida when it constructs crenelated

tumuli the night before a mating flight (see Section 2).

This ant prefers to nest in areas which are quite dry and where

the soil is compacted such as lawns and woods trails. I have found it

in large numbers under a baseball diamond in full midday sun. In






41


Mississippi, it was nesting in soil and rotting stumps (Smith, 1931).

In Florida,Smith (1944) found it constructed small crater nests in

semiboggy ground near scrub and in loam beneath moss or pine needles.

Van Pelt (1958) found it in quite well-drained areas. Whitcomb et al.

(1972) found that it built flat honeycombed mounds about 1 foot deep in

canefields. He observed that the species seemed to be thriving and

was strictly nocturnal. The Whitcomb et al. observations seem

questionable for S. (D.) pergandei and may be based upon a misdeter-

mination.






42


7. Solenopsis (Diplorhoptrum) picta Emery


Solenopsis tenuis Mayr, 1886. Zool-Bot. Gesell. Wien, Verh.
36:262. Nec. S. tenuis Mayr 1877.

Solenopsis picta Emery, 1895. Zool Jahrb., Abt. f. System. 8:278.

Solenopsis picta var. moerens Wheeler, 1915. Bull.Amer. Mus.
Natur. Hist. 34:393.

Solenopsis (Diplorhoptrum) picta. Creighton 1950. Bull. Mus.
Comp. Zool. 104:237-238.

Type locality: Florida

Types: Museo Civico di Storia Naturale "Giacomo Doria," Genoa, Italy

Range: Gulf States from Florida west to Texas


Diagnosis:


An arboreal species living in tree twigs. It has a strong

mesopropodeal impression, and the promesonotum and propodeum are

both strongly convex in profile. Petiolar node set forward from the

petiolar-postpetiolar juncture. Hairs are sparse, and of various

lengths, and do not arise from punctures. The body shining. Color

black, including appendages. A color variant occurs which is paler,

often reddish brown.


Discussion:


This species is common throughout Florida and the southeastern

states, but is limited to habitats with dead wood and twigs in which to

nest. It is a polygynous species, easily reared in the laboratory.

I have a colony captured two years ago, July 23, 1979, which

produced sexuals this past May. The sexuals are not attracted to light

traps. Van Pelt found this species most commonly in bayhead areas (1958).





43


8. Solenopsis (Diplorhoptrum) reinerti n.sp.


Diagnosis:


A small pale species. Eyes small but darkly pigmented. General

characters of workers similar to carolinensis, but queens dark in

color except for pale appendages, with small eyes and ocelli.


Description:


Worker:


Measurements: Head length 0.336 0.003 mm, head width

0.285 0.003 mm, head index 85, scape length 0.225 0.003 mm,

scape index 67, funiculus length 0.332 + 0.006 mm, club length

0.207 0.004 mm. Thorax length 0.359 0.004 mm, body length

1.58 mm. The following measurements based on 12 specimens.

Structural characters: Head quadrate, longer than broad

with weakly convex sides and straight posterior border. Eyes

small but pigmented, with two or three facets. Mandibles with

four teeth.

Thorax similar in structure to carolinensis. Propodeum

smoothly rounded in profile without definite base or declivity.

Petiole similar in shape to that of carolinensis but without

ventral concavity and the anterioventral teeth characteristic

of carolinensis (Fig. 27). Postpetiole a little wider than

petiole seen from above and weakly trapezoidal as in

carolinensis. Postpetiole shorter in proportion to length

than in carolinensis.






44


Sculpture: Head with noticeable but small punctures,

these much weaker than in pergandei, tennesseensis, abdita,

or xenovenenum n.sp. Remainder of integument smooth and

shining.

Pilosity: Head with numerous short hairs, thorax with less

numerous, somewhat longer hairs.

Color: Pale yellow or very pale brown, the integument

largely transparent.


Female:


Measurements: Head length 0.54 mm, head width 0.54 0.002 mm,

head index 100, scape length 0.40 mm, funiculus length 0.52 mm,

scape index 74, body length 2.7 mm.

Structural characters: Head as long as broad with convex

sides and straight or very slightly concave posterior border.

Clypeal teeth weak. Mandibles each with four teeth. Eyes and

ocelli small.

Thorax distinctly narrower than the head. Petiole with a

high node, and without anterioventral teeth. Postpetiole with

anterioventral flange. Wider than petiole as seen from above

and weakly trapezoidal.

Sculpture: Head with numerous well marked punctures. These

are weaker but noticeable on the thorax.

Pilosity: All surfaces with numerous hairs of moderate

length.

Color: Head, thorax, petiole, postpetiole, and gaster dark

brown. Mandibles, scapes, funiculi, and legs pale yellow or

pale brown.






45


Male: Unknown


Types:


Holotype a worker taken by core sod sampling in Dade County,

Florida, on July 29, 1974, by J. A. Reinert. Paratypes are numerous

workers and females collected by J. A. Reinert. Other paratypes are

one female (and workers later reared by her) collected on June 23,

1979, in Gainesville, Florida, by C. R. Thompson.

The holotype and several paratypes will be deposited at the

Museum of Comparative Zoology. Paratypes will also be deposited in

the Florida State Collection of Arthropods, Gainesville, Florida.

This species is named in honor of J. A. Reinert who was the first

to capture this cryptic new species.


Discussion:


Very little is known about this new species. J. C. Trager

(Department of Entomology and Nematology, University of Florida) found

sexuals and workers of this species beneath a stone at the edge of woods

on June 29, 1980. He collected reinerti males at a blacklight at

5:45 a.m. on June 26, 1980.

The workers of this species are so similar to those of carolinensis

that identifications remain questionable if only workers are available.

The dark brown to black female, however, is so different from the

large-eyed, reddish-yellow female of carolinensis that it is clear that

two taxa are involved. Although presently known from only two Florida

localities, the species may prove to be common and widespread.





46


9. Solenopsis (Diplorhoptrum) tennesseensis M. R. Smith


Solenopsis (Diplorhoptrum) longiceps M. R. Smith, 1942. Proc.
Entomol. Soc. Wash. 44:210. Preoccupied by Forel,1907.

Solenopsis (Diplorhoptrum) longiceps M. R. Smith. Creighton,
1950. Bull. Mus. Comp. Zool. 104:236-236.

Solenopsis (Diplorhoptrum) tennesseensis M. R. Smith, 1951.
In Muesebeck, U.S.D.A. Agr. Monog. 2:814. N. name.

Type locality: Hamilton Co., Tennessee.

Types: United States National Museum, Washington, D. C.

Range: Florida west to Texas and north to latitude of Tennessee.


Diagnosis:


We did not find this subterranean species in Florida in spite of

previous records. It has probably been confounded with the new species

S. (D.) xenovenenum. S. (D.) tennesseensis is unusual in having a

slender head. The thorax in profile is straight dorsally and the

propodeum has a distinct base and declivity. Head and thorax with

numerous short hairs arising from distinct punctures. It differs from

S. (D.) abdita in not having a clear median streak free from punctures

and hairs on the head.


Discussion:


This study has shed no new light on the biology or distribution

of S. (D.) tennesseensis. Little information is present in the

literature. This species is known primarily from the type series.

The range given by Creighton (1950) may not be accurate.






47


10. Solenopsis (Diplorhoptrum) texana Emery


Solenopsis polluxvar. texana Emery, 1895. Zool Jahrb., Abt. f.
System. 8:278.

Solenopsis texana Forel, 1901. Ann. Soc. Entomol. Belg. 45:345.

Solenopsis rosella Kennedy, 1938. Can. Entomol. 70:232.

Solenopsis (Diplorhoptrum) texana Creighton, 1950. Bull.
Mus. Comp. Zool. 104:238.

Type locality: Texas

Types: Museo Civico di Storia Naturale "Giacomo Doria", Genoa, Italy.
A questionable series is at the Museum of Comparative Zoology at
Harvard.

Range: Central Texas and southeastern states north to Canada


Diagnosis:


Similar to molesta, but head more slender, thorax distinctly more

slender. Postpetiole a little wider than the petiole seen from above.

Hairs sparse and of mixed lengths. No piligerous punctures. Head and

gaster often weakly infuscated.

S. (D.) texana is larger than carolinensis and the hair patterns

are different. The small females with the very large eyes seem to be

unique to carolinensis.


DiscusSion:


I have not been able to find this species in Florida. Although

Krombein et al. (1971) list this species from Florida, I suspect exam-

ination of the specimens would show them to be carolinensis. Authentic

specimens of S. (D.) texana may eventually be found in the state.





48


11. Solenopsis (Diplorhoptrum) truncorum Forel


Solenopsis texana race truncorum Forel, 1901. Ann. Soc.
Entomol. Belg. 45:346.

Solenopsis molesta var. castanea Wheeler, 1908. Bull. Amer.
Mus. Natur. Hist., 24:430.

Solenopsis (Diplorhoptrum) truncorum Creighton, 1950. Bull.
Mus. Comp. Zool. 104:239.

Type locality: Faisons, North Carolina

Types: Museum d'Histoire Naturelle, Geneva, Switzerland.

Range: Southeastern U.S. and west to the Rocky Mountains.


Diagnosis:


A large, dark-colored species with rather sparse scattered hairs

of mixed lengths. This species is common in the mountains of the

western U.S., but also occurs in the eastern Appalachian Mountains.


Discussion:


The large dark brown castanea was synonymized under truncorum

by Creighton (1950). No types of truncorum are present in this country,

but the types of castanea were compared with various Florida species

by Dr. William F. Buren. The Florida specimens did not match the

types of castanea.

I have not found this species in Florida, although Smith (1979)

lists the species as occurring in this state.





49


12. Solenopsis (Diplorhoptrum) xenovenenum n.sp.


Solenopsis tennesseensis Krombein, Hurd, Smith, Burks.
Catalog of Hymenoptera in America North of Mexico.
Smithsonian Institution Press, Washington, D.C.
1979. p. 1388. in part, nec M. R. Smith



Diagnosis:


Very small yellow species. Head with prominent punctures,

pilosity short and numerous on all surfaces. Head elongate as in

tennesseensis. Eyes reduced to a single facet. Males and females

with characteristic darkly infuscated wings.


Description:


Worker:


Measurements: Head length 0.317 0.002 mm, head width

0.245 0.002 mm, head index 77, scape length 0.191 0.002,

scape index 60, funiculus length 0.296 0.003 mm, club

length 0.191 0.002 mm. Thorax length 0.336 0.004 mm, body

length 1.1 mm. The preceding measurements based on 18

specimens.

Structural characters: Head (Fig. 30) distinctly longer

than broad with weakly convex sides and straight or slightly

excised posterior border. Antennal scapes reaching 2/3 the

distance from insertions to hind corners of head. Eye reduced

to one facet, usually pigmented. In profile head somewhat

flattened dorsally, slightly convex ventrally. Anterior edge

of clypeus angularly separated from dorsal surface of mandibles

seen in profile.






50


Thorax weakly convex; propodeum rounded without definite

base or declivity (Fig. 29). Petiole without anterioventral

tooth. From above the petiole and postpetiole are about the

same width. Postpetiole with rounded sides.

Sculpture: Dorsum of head covered with distinct punctures

but these not as strong as in tennesseensis or abdita. Dorsum

of promesonotum also with some weak punctures. All other

surfaces smooth and shining.

Pilosity: Hairs short and numerous on all surfaces.

There may be some longer hairs on the thorax, gaster, and petiole.

Color: Yellow to pale yellowish brown.


Female:


Measurements: Head length 0.59 mm, head width 0.64 mm, head

index 108 mm, scape length 0.46 mm, scape index 78, funiculus

length 0.60 mm, total body length 3.24 mm.

Structural characters: Head quadrate, a little longer than

broad with both sides and occipital border nearly straight or

only slightly convex. Scapes nearly reaching hind corners of

the head. Ocelli rather small, measuring 0.02 mm in diameter

and separated from each other by at least one diameter.

Thorax slightly narrower than head. Petiole without

anterioventral tooth. Node of petiole with slightly excised

superior border seen from behind. Petiole and postpetiole of the

same width. Postpetiole weakly trapezoidal as seen from above,

wider posteriorly than anteriorly.






51


Sculpture: Head with scattered moderate punctures;

mesonotum with weak punctures. Pleurae of propodeum, petiole,

and postpetiole weakly striate or shagreened. All other

surfaces smooth and shining.

Pilosity: Body and appendages with numerous short hairs.

Wings with dark brown veins and stigma, membranes also com-

pletely infuscated with brown.

Color: Entire body including appendages brownish to dark

brown.


Male:


Measurements: Head length 0.40 mm, head width (including

eyes) 0.50 mm, thorax length 1.08 mm, petiole length 0.34 mm,

eye length 0.19 mm, body length 2.82 mm.

Structural characters: Antennae 12-jointed, last two joints

and particularly the last joint longer than other funicular joints,

but not enlarged or clublike. Eyes occupying about one-half of

head length, ocelli 0.065 mm in diameter. Mandibles weak, each

with 2 or 3 teeth. Head trapezoidal in shape.

Thorax without Mayrian furrows on the mesonotum. Petiolar

node with slightly concave superior border.

Sculpture: Head and dorsum of thorax with weak punctures.

Propodeum sculptured with striato-punctate markings. Petiolar

node punctate.

Pilosity: All surfaces with numerous short hairs.

Color: Dark brown, including the appendages. Wing veins

and membranes completely infuscated with brown.






52


Types:

Holotype--a worker collected by Naves trap on June 16, 1979, by

C. R. Thompson. Paratypes are numerous workers taken in Naves traps

June to October, 1979.

The holotype and several paratypes will be deposited at the

Museum of Comparative Zoology. Paratypes will also be deposited in

the Florida State Collection of Arthropods, Gainesville, Florida.

Discussion:


This species is so named because it was found by Dr. Tappey Jones

(Univ. of Georgia) to have (5Z,8E)-3-heptyl-5-methyl pyrrolizidine as

the main constituent of its venom. This compound is new to biology.

The species is common throughout the state in many habitats.

Males and females have been observed in an afternoon flight at

Homestead, Florida, in July, 1964. Males have been taken from a spider

web in Gainesville, Florida, on July 30, 1978, and from a light trap in

Miami Beach (June 3, 1947). This is the smallest Diplorhoptrum species

in the United States and has been taken from under stones, unlike most

other species of the subgenus in Florida.











PLATE 1

Figure 1. Lateral view of worker of S. (D.) abdita n. sp.
(65X)

Figure 2. Head of the worker of S. (D.) abdita n. sp.
(120X)

Figure 3. Petiole and postpetiole of worker of S. (D.)
abdita n. sp. (340X)

Figure 4. Dorsal view of worker of S. (D.) abdita n. sp.
(50X)






54
























Ato~


















ALI












PLATE 2

Figure 5. Lateral view of worker of S. (D.) carolinensis
Forel (60X)

Figure 6. Head of the worker of S. (D.) carolinensis Forel
(130X)

Figure 7. Petiole and postpetiole of worker of S. (D.)
carolinensis Forel (290X)

Figure 8. Dorsal view of worker of S. (D.) carolinensis Forel
(56X)






56












PLATE 3

Figure 9. Lateral view of worker of S. (D.) corticalis Forel
(90X)

Figure 10. Head of the worker of S. (D.) corticalis Forel
(200X)

Figure 11. Petiole and postpetiole of worker of S. (D.)
corticalis Forel (360X)

Figure 12. Dorsal view of worker of S. (0.) corticalis Forel
(65X)






58












PLATE 4

Figure 13. Lateral view of worker of S. (D.) nickersoni n. sp.
(75X)

Figure 14. Head of the worker of S. (D.) nickersoni n. sp.
(120X)

Figure 15. Petiole and postpetiole of worker of S. (D.)
nickersoni n. sp. (420X)

Figure 16. Dorsal view of worker of S. (D.) nickersoni n. sp.
(65X)






60






































-,ONO












PLATE 5

Figure 17. Lateral view of worker of S. (D.) pergandei Forel
(79X)

Figure 18. Head of the worker of S. (D.) pergandei Forel
(98X)

Figure 19. Petiole and postpetiole of worker of S. (D.)
pergandei Forel (165X)

Figure 20. Dorsal view of worker of S. (D.) pergandei Forel
(75X)






62
























17












PLATE 6

Figure 21. Lateral view of worker of S. (D.) picta Emery
(70X)

Figure 22. Head of the worker of S. (D.) picta Emery
(140X)

Figure 23. Petiole and postpetiole of worker of S. (D.)
picta Emery (378X)

Figure 24. Dorsal view of worker of S. (D.) picta Emery
(70X)





64


















22


















23 24
,1~.8il ow.
i iiw ....






o ili~iii

2 3 .. iiilii











PLATE 7

Figure 25. Lateral view of worker of S. (D.) reinerti n. sp.
(90X)

Figure 26. Head of the worker os S. (D.) reinerti n. sp.
(140X)

Figure 27. Petiole and postpetiole of worker of S. (D.)
reinerti n. sp. (460X)

Figure 28. Dorsal view of worker of S. (D.) reinerti n. sp.
(50X)





66












PLATE 8

Figure 29. Lateral view of worker of S. (D.) xenovenenum n. sp.
(83X)

Figure 30. Head of the worker of S. (D.) xenovenenum n. sp.
(150X)

Figure 31. Petiole and postpetiole of worker of S. (D.)
xenovenenum n. sp. (460X)

Figure 32. Dorsal view of worker of S. (D.) xenovenenum n. sp.
(84X)






68












PLATE 9

Figure 33. Cluster of mating flight tumuli of S. (D.) pergandei
Forel

Figure 34. Mating flight tumulus of S. (D.) pergandei Forel

Figure 35. Mating flight tumulus of S. (D.) pergandei Forel






70











Jrr







~'A
iiiil ,i

sts


va















34
u















'AL








S35






71


Section II
Subterranean Distribution of Diplorhoptrum Species


Mosaic distribution of ant species is well documented in cacao

plantations (Majer, 1972; Leston, 1973), but these studies involved

arboreal species in easily sampled ecological niches, i.e., cocoa trees.

Nothing was known of the distribution of Diplorhoptrum species below

ground, particularly as no surface structures are constructed by these

ants, with the exception of S. (0.) pergandei mating flight tumuli.

Accordingly, 5 x 10 meter grids were set up, and experimental

trapping was begun in June, 1979. The results were immediate and

surprising. Of 100 traps put down June 17, in 24 hours 59 were positive

for ants and, of these, 43 contained Diplorhoptrum. Diplorhoptrum were

captured in as many as 75 per cent of the traps during July and August

and as few as 3 per cent in January. Some traps contained over 300

ants. An example of the results is shown in Fig. 36 for the longleaf

pine-turkey oak woods. Five species of Diplorhoptrum were captured in

the traps during this study. All were present in the first set of

traps put down on June 17. Numbers of traps in which each Diplorhoptrum

species was captured throughout the year are presented in Figs. 37 and

38.

It is evident that S. (D.) carolinensis was the dominant subterran-

ean ant in both habitats. S. (D.) pergandei was absent from the field

habitat, and present at only two trap locations in the woods grid. S. (D.)

xenovenenum also had a distinct pattern in that they were captured in

only 2 traps in the field, but were evenly distributed in the wood.





72







-0 -...........n n
53 S3:::::o 73//*/a*




*.*.*"** .*.* ..*.*"S ( D ) x*eno*-'







.. ............. .
S.. ....:.. (.) pergandei
////////// ///////////






.. .. .... .......... .. . ..
.. ........











S/////////
5'"'*'" E3 S. (D.) caroli-

..... ..........nenss

I..: 4 0 S (D.) xeno-

..... :::::::: ..... ..::... ..







































Figure.36. Example of Naves trap samples of Diplorhoptrum and
other species distributin iS. alD.) abditale
...... ..S (S.) pergandei




































turkey oak woods on June 24, 1979, at Gainesville,
:::::::&'::^::::: ^:::: p Other genera::



// ........ .. '.'.'.

,,, ,,~,~,, ,,,.,,,,, ::::::..:.:.:::

/////// .//////.// ....



.//,/////, /- : .::.: './/////////
,- - -- - - .... ...... ... .. . . . ..
-...........




62 ::: ::: %^^^?^


............ .... ..... .. ///H/H










Figure. 36. Example of Naves trap samples of Diplorhoptrum and
other species distribution in a long leaf pine-
turkey oak woods on June 24, 1979, at Gainesville,
Florida.





73








S. (D.) carolinensis


MS. (D.) abdita n. sp.


S. (D.) xennvenenum n. sp.


S. (D.) pergandei


S/ ::. S. (D.) nickersoni n. sp. .:.:








40 /



0 / / / / /
S / / / / / / / /




/ / / // // /
.... ...




/ /







J J A S O N D J F M A M J
1979 Month 1980



Figure 37. Diplorhoptrum species captured by Naves trap in
an open field at Gainesville, Florida, from June
1979-June 1980.
_ 20 // / / / / / / / / / /












Figure 37. Diplorhoptrum species captured by Naves trap in
an open field at Gainesville, Florida, from June
1979-June 1980.





74









3S. (D.) carolinensis

SS. (D.) abdita n. sp.


S. (D.) xenovenenum n. sp.


S S-. (D.) pergandei

../ / ^S. (D.) nickersoni n.sp ".:.?.-':





............. :...........i.i..i..


.. /......... .... ... . / / /...
I-


/,/// //

S / / / /___/
I I I I ....... ....... ..




J J A S N J F M A M J
1979 Month 1980


Figure 38. Diplorhoptrum species captured by Naves trap in
a long leaf pine-turkey oak woods at Gainesville,
Florida, from June 1979-1980.






75


Ant activity dropped sharply between October and November and began

to increase the following year between April and May. Having observed

the sharp cessation of activity in the fall, I suspected soil tempera-

tures might be a factor and began to monitor them. On April 15 the

field soil temperatures taken at 14 cm were 15.3, 16.3 and 17.00 C.

The wood soil temperatures were 16.0, 16.3 and 17.00 C. By May 16 a

distinct increase was evident: field soil temperatures were 23.3, 23.3

and 24.00 C while wood soil temperatures were 21.0, 21.5 and 21.50 C.

These data indicate that soil temperature may be a major factor in

seasonal Diplorhoptrum activity patterns.

The major question posed by these collection data is how many nests

and of what species are present? Estimates of colony numbers and

territorial sizes can be made based on the following assumptions:

1. Few ant species build one-chambered nests, and all known

Solenopsis build multi-chambered nests. It can be assumed Diplor-

hoptrum have multi-chambered nests.

2. All known Solenopsis have discrete nests. Large populations

covering large areas without discrete nests probably do not occur in

Diplorhoptrum species. Diplorhoptrum are here assumed to have discrete

nests and foraging areas which do not extensively overlap.

3. From the appearance of S. (D.) pergandei tumuli clusters, which

are constructed following rain (Fig. 33), the network of chambers and

tunnels below may be assumed to be diffuse. The nest probably occupies

a region comparable to the size of the cluster on the surface and not

more than 1 or 2 meters in area.

4. Each ant colony controls available food sources over as wide

an area as possible. Dominant species may be assumed to control large






76


areas; subdominants to control proportionately smaller areas.

5. Whether dominant or subdominant, the closer a food source is

to a nest, the more likely that colony will be able to successfully

exploit and control the food source.

6. Subdominants or non-dominants probably can not maintain

complete control over foraging areas unless near their nests. Specific

traps (i.e., Meter 8 with S. 0.) nickersoni or Meters 70 and 71 (Fig. 37)

with S. (D.) pergandei) were nearly always positive with certain

subdominants, therefore it is probable that these traps were located

near a nest of the subdominant, and that a single colony of the sub-

dominant is indicated by each of these locations.

7. It can be assumed that any trap location in which one species

was consistently collected and which was nearly always positive is

likely to be close to the nest location of a dominant.

Therefore the nest of each subdominant, and the nest areas of each

dominant should be countabe with reasonable accuracy. With these

assumptions, and the summation method of assembling the data, the

nesting pattern and general foraging areas of the various species

sampled can be estimated. Data were summed by counting the numbers of

traps positive for each species, then multiplying each number by the

percentage of the time a trap was positive for that species. For

example, S. (D.) carolinensis was present,in Trap 12,5 out of 7 or

77.7% of the times that the trap was positive with Diplorhoptrum.

Multiplying 5 x 77.7% gives an experimental summation number of 544.

The summation numbers were then arbitrarily divided into four groups and

assigned to a pattern series, as shown in Figs. 39-43. From these

patterns, rough estimates of the shape of foraging areas for each

individual nest can be drawn.





77


S. (D.) carolinensis mosaic patterns were the most complex. In the

field there appear to be four colonies with wide-ranging territories

(Fig. 39). Foraging areas of two additional colonies appear to be only

partially present in the grid. In the woods site, there is probably

one large colony and a second smaller colony with a much smaller

foraging area around Meter 82 (Fig. 41).

The colony and foraging patterns of S. (D.) abdita and S. (D.)

xenovenenum are less complex. There appear to be 4 colonies of S. (D.)

abdita in the field grid and only probably two colonies in the woods,

with perhaps an incipient colony in Meters 84-85 (Figs. 40,42). S. (D.)

xenovenenum occupied only one meter in the field site, but appeared to

have three colonies (Fig. 43) and part of the foraging territory of a

fourth in the woods site.

The data in Figs. 39-43 are subject to more than one interpretation

and boundaries could easily be drawn somewhat differently. In addition,

the true correlation of colony numbers and territories indicated by

trapping data with those actually present in the field remains unknown.

It is hoped that the Naves trap method may eventually be found to

indicate true Diplorhoptrum territories and colony numbers.

In the field site S. (D.) carolinensis is the dominant species while

S. (D.) pergandei is an occasional dominant, or to use Majer's (1972)

terminology sensu strictu, a sub-dominant, i.e., a species capable at

times of becoming a dominant. Yet many more S. (D.) pergandei queens

were found during field excavation and in light traps than were S. (D.)

carolinensis. This would be consistent with a species which does not

expend energy in large queens and mating flights, but whose small queens

may mate mostly in the nest and remain in the nest to produce large,





78


diffuse colonies. Dr. J. C. Nickerson collected a colony of S. (D.)

carolinensis which had 6 queens. In the laboratory a number of S. (D.)

carolinensis queens will found a nest together amicably, and will

remain together without.fighting after workers are reared. These data

support the low energy--small queens hypothesis.

A second method of data analysis undertaken was a breakdown of

positive trap counts by month of the year as shown in Figs. 44 and 45.

Concentrations and suspected nest locations generally coincided with

those obtained from the summation method. Comparisons must be made

with caution, however, as data presented in Figs. 44 and 45 cover a

year while Figs. 39-43 include data from a five month period.

The greatest weight was placed on the five month summation study

results, after the tremendous fluctuations in species location data

were noted. Fluctuation in colony locations was greatest following the

relative inactivity of the winter months. Twenty traps remained

positive for the same Diplorhoptrum species over the entire year.

Intramonthly repeatability (June to Oct.) was high: 90% + 2.0, while

intermonthly repeatability was substantial: 63% + 3.0. The number of

traps common to the same species on June 17, 1979 and June 18, 1980

(first and last experimental dates) was eight, while the number of

corresponding traps with different species was 11 and the remaining

traps were positive on only one day or not at all.

In addition to the summation and by-month analyses of Diplor-

hoptrum distribution, a third method was proposed based on the

following observations and hypothesis: during November through

February, Diplorhoptrum activity was low, with S. (D.) pergandei and

S. (D.) abdita activity ceasing entirely. If one.makes the assumption





79










Summation Values
S[D] 0-300

S4 301-600

(1 601-1 ,000
2 3 1i,ooo+
row | 1,000+






1 .1 1 1 I 2 I 1 1 1
















Figure 39. Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) carolinensis
in an open field at Gainesville, Florida.





80


1 20 21 1111111114



2 I 22



3 23 j Summation Values

0l [0-50

' I I 7 llllllllllll51-200


II 201-700



l5 26 35 R






















Figure 40. Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) abdita
in an open field at Gainesville, Florida.
in an open field at Gainesville, Florida.




81

51 1 0 7 919






15T 7 llll1 Summation Values
I|0O-300

54 ]I301-600

O1 601-1 ,000
16 9!
[1000+

11 1 ooo+









56 6 81 I1ca "






Figure 41. Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) carolinensis in
a long leaf pine-turkey oak woods at Gainesville,
Florida.




82
7"''- --- T --'" -"
70 71 90 91


52 I 72 89 92


76 13 88 93 Summation Values
o 0-50

5 67 74 87 94 [1151-200

___ 201-700
5 66 75 86 95
Rm 700+

56 65 76 8 I96


57 64 77 8I 97


58 63 78 83 98


59 & 7 1 82 99


10 81 100




Figure 42. Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) abdita in a long
leaf pine-turkey oak woods at Gainesville, Florida.





83


? 1 ""0 18;



5: I !5 72 1 8!1
11-- - -----



5 8 73 1 3 Summation Values

M1 o-50

6 8- 4 :' [ID51-200

I ... 201-599

mB 600+

56 65



57 6 7 I ,


il 63 1 98














Figure 43. Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (D.) xenovenenum
in a long leaf pine-turkey oak woods at Gainesville,
Florida.





84

1 20 21 40 41


2 19 22 39 42


3 18 23 38 43carol
OO)S. (D.) caroli-
S A A 0nensi s

4 17 24 37 44 S. (D.) abdita
A AlAA A

5 16 25 36 45


6 15 26 35 46


7 14 27 34 47
AA Ai ( .NA
IA A
8 13 28 33 48




/2\ A 2 @A A
9 12 29 32 49


10 11 30 31 50



Figure 44. Number of months each trap site in an open field
at Gainesville, Florida, was positive for three
three species of Diplorhoptrum (June 1979-June 1980).




85

51 10 71 0 91


52 02 69 7289 89 92
[2] [1] F2] 1]
53 ( 68 73 88 S. (D.) caroli-
A 2-1 nensis
54 67 74 0 17@ 94 4 .S. (.) abdita
A 2 [ [ 2] S. (D .) xeno-
venenum
55 1 6 75 8 , 95


56 65 1) 76 85 96

-n

M Ri -- [2]
-I
57 64 77 84 97


58 "6 78 9




io ' ) +o "(i ,o
60 61 80 (:1) 100



Figure 45. Number of months each trap site in a long leaf pine-
turkey oak woods at Gainesville, Florida, was positive
for three species of Diplorhoptrum (June 1979-June 1980).






86


that the ants do not forage far from the nest in the cold, it should be

possible to map nest locations more accurately than at other times of

the year.

When the winter distribution maps were prepared, however, it was

found that many traps were positive, but only once or twice, making

pattern discernment impossible.

Figures on the distribution of S. (D.) pergandei and S. (D.)

nickersoni were not included, as these species were extremely localized.

S. (D.) pergandei appeared only in woods traps with one established

nest in or near Meter 70, which included territory in Meters 69-72.

S. (D.) pergandei is a sub-dominant. It successfully excluded S. (D.)
carolinensis from Meter 70 for an entire year. S. (D.) nickersoni

appeared to have an even more scattered distribution except for captures

by Traps 8 and 13. It is also a sub-dominant, able (Fig. 40) to

exclude S. D(.) carolinensis from Meter 8, but not S. (0.) abdita.

Only Diplorhoptrum species were taken from the field traps in this

study, but other ant genera came to the woods traps: Pheidole dentata,

Pheidole floridana, Pheidole metallescens, Brachymyrmex depilis and (ne

collection) Solenopsis geminata. Records of these ants were kept but

are not included in this study. It is evident from the approximately

3 to 14% of the traps which captured this group, that the greatest

competitors Diplorhoptrum have among other ants are species of Pheidole.

In summary, totally unexpected and extremely large numbers of

workers of five Diplorhoptrum species were found in an open field and in

long leaf pine-turkey oak woods. Three of the species were new. By

constructing a system of assumptions and by summing numbers of positive

traps and percentage of those traps for each species, diagrams of






87


possible nest numbers and territorial boundaries were constructed.

S. (D.) carolinensis was the dominant species in both habitats while

S. (D.) abdita was common, particularily in the field. Of the less

common species, S. (D.) xenovenenum was more often found in the woods,

S. (D.) nickersoni was rare in both habitats and S. (D.) pergandei was

only in the woods site. This was a beginning study of previously

unknown or poorly known species. From the preliminary data no habitat

preferences for the various species should be inferred at this time.






88







Section III
The Mating Flights of S. (D.) pergandei


Solenopsis (Diplorhoptrum) pergandei is the largest species of the

subgenus that occurs in Florida. It is also the only species that

constructs a visible structure (tumulus) surrounding its nest opening

at the soil surface. From June through early September, within 24 hours

after a rain, S. (D.) pergandei constructs unique, crenelated tumuli

for early morning mating flights.


Tumuli Construction


The tumuli are constructed with passages wide enough for several

females to pass (ca. 6 mm ) and with walls twice or more their body

height (ca. 5-10 mm). I have seen some tumuli 16 cm in diameter. One

benefit of these passages is probably an increase in the number of

sexuals that can remain at the soil surface in preparation for a flight

while still remaining under the protection of the workers. On June 23,

1979, at 4:20 a.m., I observed sexuals massed at the surface even

though this flight did not occur until nearly 6 a.m.

A second function of these tumuli is probably to present a flight

take-off surface for the departing sexual forms, although I have

observed the heavy females climbing up grass blades near the nest.

On morningswhen flights did not occur, the ants constructed tumuli

of two additional types. These I have called "closed" tumuli and

"digging-out" tumuli. The closed tumuli were sometimes constructed on






89


mornings following rain when flights did not occur. The ants constructed

chambers at ground level, then formed a thin roof of soil pellets with

worker-sized entrances. No flights were ever observed from these

structures.

Digging-out tumuli apparently were for exactly that purpose. Other

conditions apparently were not favorable for flights, and the ants were

most likely repairing passages which had collapsed with the rain. These

tumuli were simply piles of excavated soil deposited near the entrance.


Flight Factors


Preliminary studies in the summer of 1978 suggested that S. (D.)

pergandei mating flights did not occur unless there had been measurable

precipitation during the previous 24 hours. Data gathered on 30 flights

from June to September of 1979, when they ceased in the Gainesville

area, showed that 83% (25) of the flights occurred following a rain.

On seven additional mornings tumuli were constructed but no flights

occurred. The ants frequently constructed closed, digging-out and a

few crenelated tumuli on non-flight mornings. This indicated that con-

ditions became unfavorable during the night, or that additional stimuli

utilized by the ants to initiate flight were not favorable.

As the summer progressed, mating flights occurred slightly later

each week. In late June, flights began at 5:50 a.m. In early August,

they were beginning at ca. 6:08 a.m. This suggested that an additional

factor potentially triggering flights was light. A commercial light

meter was used to attempt light readings at flight times. It was so

dark in the half hour before dawn when these ants flew that almost no

light values were registered. Readings at 6:41 a.m., shortly after a




Full Text
84
'
20

21
A
40
A
41
A
2

19
A
22
39

42
A
3

18

23

38
A
43
A
4
A
17
A
24
A
37
A
A
on

16
A
25
A
36
A
45

6
A
15

26

35

46
A
7
A
14
A
27
A
34

47
.A
8
A
13
A
28
A
33
A
48
A
9

12
A
29

32
A
49
A
10
A
ii

30
A
31
A
50
A
S_. (_D.) carol i -
^ nensis
/\ S_. (D_.) abdita
Figure 44. Number of months each trap site in an open field
at Gainesville, Florida, was positive for three
j.m three species of Diplorhoptrum (June 1979-June 1980).


LITERATURE CITED
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105


112
Smythe, R.V. and H.C. Coppel. 1973. The eastern subterranean termite
Reticuli termes flavipes (Kollar), and the common thief ant,
Solenopsis molesta (Say), in the laboratory, with notes on other
associated ant species. Trans. Wisconsin Acad. Sci. Arts Letters
61:95-102.
Srivastava, B.K. and H.R. Bryson. 1956. Insecticidal seed treatment
for control of the thief ant. J. Econ. Entomol. 49:329-333.
Talbot, M. 1953. Ants of an old-field community on the Edwin S.
George Reserve, Livingston County, Michigan. Contrib. Lab.
Vertebrate Biol. Univ. Michigan 63:1-13.
Talbot, M. 1965. Populations of ants in a low field. Insectes
Sociaux 12:19-48.
Talbot, M. 1975. A list of the ants (Hymenoptera:Formicidae) of the
Edwin S. George Reserve, Livingston County, Michigan. Great Lakes
Entomol. 8:245-246.
Thorn, G. 1935. Notes on free-living and plant parasitic nematodes.
4. A new slide ring material. Proc. Helmintho. Soc. Wash. 2:98.
Van Pelt, A. 1963. High altitude ants of the Southern Blue Ridge.
Amer. Midland Natur. 69:205-223.
Van Pelt, A.F. 1947. A preliminary key to the worker ants of Alachua
County, Florida. Florida Entomol. 30:57-67.
Van Pelt, A.F. 1966. Activity and density of old-field ants of the
Savannah River Plant, South Carolina. J. Elisha Mitchell Sci.
Soc. 82:35-43.
Van Pelt, A.F., Jr. 1958. The ecology of the ants of the Welaka
Reserve, Florida (Hymenoptera:Formicidae). Part II. Annotated
list. Amer. Midland Natur. 59:1-57.
Warren, L.O. and E.P. Rouse. 1969. The ants of Arkansas. Arkansas
Agr. Exp. Sta. Bull. 742:1-67.
Webster, F.M. 1893. Insects affecting the blackberry and raspberry.
Ohio Agr. Exp. Sta. Bull. 45:151-217.
Wesson, L.G., Jr., and R.G. Wesson. 1940. A collection of ants from
south central Ohio. Amer. Midland Natur. 21:89-103.
Wheeler, G.C. and J. Wheeler. 1955. The ant larvae of the Myrmicine
tribe Solenopsidini. Amer. Midland Natur. 54:119-141.
Wheeler, G.C. and J. Wheeler. 1960. Supplementary studies on the
larvae of the Myrmicinae. Proc. Entomol. Soc. Wash. 62:1-32.
Wheeler, G.C. and J. Wheeler. 1963. The ants of North Dakota. Univ.
of North Dakota Press, Grand Forks. 326 p.


10
S. (D.) molesta appears to have few natural enemies, although
research lags in this area. Beal (1911, 1912) found that a flicker,
Colaptes auratus L. subsp., and the kingbird or bee martin, Tyrannus
tyrannus (L.) feed on S.. ([).) molesta. No less than 39 species of birds
were observed feeding on a mating flight of S.. ([).) molesta (Judd,
1901). Diplorhoptrum probably have a number of ant enemies, but only
two are reported: Hung (1974) found that 10% (or 80) of the ants'
heads in the garbage pile of a Conomyrma nest were those of S_. (2-)
molesta. Burn et al. (1977) suggest false phragmosis evolved by
Pheidole lamia Wheeler serves as a defensive tactic against subterranean
ants, mainly Diplorhoptrum.
It is fortunate that two astute observers have published their
observations on the mating flights of S.. (I).) molesta. In Kansas,
Hayes (1925) observed a flight at 5 p.m. on July 27, 1920, which con
tinued until dusk, and a flight July 5, 1921. Both were preceded by
heavy rain. He noted that mating occurred in the air, that females
outnumbered males (unusual in ants), and that males mated more than
once. Farther north in Canada, late August flights occurred
(Macnamara, 1945; Wheeler, 1916) and Macnamara observed a dense evening
swarm, 3-4 ft in diam. and at its lowest point about 3 ft off the
ground. He saw that the swarm was sluggish and noticed, most impor
tantly, that the females were carrying workers on their bodies. Wing
(1951) reported that W. L. Brown found approximately 20% of the S.. (£.)
mol esta females in a Philadelphia flight had one or rarely two workers
attached to their legs.


109
Hunter, W.D. and W.E. Hinds. 1904. The Mexican cotton boll weevil.
USDA Div. Entomol. Bull. 45:1-116.
Jaynes, H.A. and P.E. Marucci. 1947. Effect of artificial control
practices on the parasites and predators of the codling moth.
J. Econ. Entomol. 40:9-25.
Jenne, E.L. 1909. The codling moth in the Ozarks. USDA Bur. Entomol.
Bull. 80:1-32.
Jones, T.H. 1980. (5Z-8E)-3-heptyl-5-methyl pyrrolizidine from a
thief ant. (Submitted).
Jones, T.H., M.S. Blum, and H.M. Fales. 1979. Synthesis of unsym-
metrical 2,5-DI-n-alkylpyrrolidines : 2-hexyl-5-pentyl pyrrolidine
from the thief ants Solenopsis molesta, ,S. texana, and its
homologues. Tetrahedron Letters 12:1031-1034.
Jones, T.H., M.S. Blum, H.M. Fales, and C.R. Thompson. (5Z,8E)-3-
heptyl-5-methyl pyrrolizidine from a thief ant. (In press).
Judd, S.D. 1901. The relation of sparrows to agriculture. USDA
Biol. Surv. Bull. 15:1-98.
Kennedy, C.H. 1938. Solenopsis rosella Kennedy, a new ant from
Southern Ontario. Can. Entomol. 70:232-236.
King, G.B. 1895. The study of the Formicidae of Lawrence, Mass.
Entomol. News 6:220-223.
King, G.B. 1896. Mixed colonies of ants. Entomol. News 7:167-170.
King, G.B. 1897. Some ants and myrmecophilous insects from Toronto.
Can. Entomol. 29:100-103.
King, G.B. 1901a. A check-list of the Massachusetts Formicidae with
some notes on the species. Psyche 9:260-262.
King, G.B. 1901b. Some new records of the New England Formicidae.
Psyche 9:270-271.
Landis, B.J. 1967. Attendance of Smynthurodes betae (Homoptera:
Aphidae) by Solenopsis molesta and Tetramorium caespitum
(Hymenoptera:FormicidaeT AnrT. Entomol. Soc. Amer. 60:707.
Leston, D. 1973. The ant mosaic-tropical tree crops and the limiting
of pests and diseases. Pans 19:311-341.
MacConnell, J.G., M.S. Blum, W.F. Burn, R.N. Williams, and H.M. Fales.
1976. Fire ant venoms: Chemotaxonomic correlations with alkaloid-
al compositions. Toxicon 14:69-78.
Macnamara, C. 1945. A note on the swarming of Solenopsis molesta Say
(Hymenoptera). Can. Entomol. 77:40.


82
Summation Values
CD 0-50
CDD 51 -200
El] 201 -700
11700+
Figure 42. Five month (June-Oct., 1979) summation of the
distribution by trapping of S_. (D.) abdita in a long
leaf pine-turkey oak woods at Gainesville, Florida.


76
areas; subdominants to control proportionately smaller areas.
5. Whether dominant or subdominant, the closer a food source is
to a nest, the more likely that colony will be able to successfully
exploit and control the food source.
6. Subdominants or non-dominants probably can not maintain
complete control over foraging areas unless near their nests. Specific
traps (i.e., Meter 8 with S^. (D.) nickersoni or Meters 70 and 71 (Fig. 37)
with 5L (£.) pergandei) were nearly always positive with certain
subdominants, therefore it is probable that these traps were located
near a nest of the subdominant, and that a single colony of the sub
dominant is indicated by each of these locations.
7. It can be assumed that any trap location in which one species
was consistently collected and which was nearly always positive is
likely to be close to the nest location of a dominant.
Therefore the nest of each subdominant, and the nest areas of each
dominant should be countatfe with reasonable accuracy. With these
assumptions, and the summation method of assembling che data, the
nesting pattern and general foraging areas of the various species
sampled can be estimated. Data were summed by counting the numbers of
traps positive for each species, then multiplying each number by the
percentage of the time a trap was positive for that species. For
example, S_. (j).) carol inensis was present, in Trap 12,5 out of 7 or
77.7% of the times that the trap was positive with Diplorhoptrum.
Multiplying 5 x 77.7% gives an experimental summation number of 544.
The summation numbers were then arbitrarily divided into four groups and
assigned to a pattern series, as shown in Figs. 39-43. From these
patterns, rough estimates of the shape of foraging areas for each
individual nest can be drawn.


49
12. Solenopsis (Diplorhoptrum) xenovenenum n.sp.
Solenopsis tennesseensis Krombein, Hurd, Smith, Burks.
Catalog of Hymenoptera in America North of Mexico.
Smithsonian Institution Press, Washington, D.C.
1979. p. 1388. in part, nec M. R. Smith
Diagnosis:
Very small yellow species. Head with prominent punctures,
pilosity short and numerous on all surfaces. Head elongate as in
tennesseensis. Eyes reduced to a single facet. Males and females
with characteristic darkly infuscated wings.
Description:
Worker:
Measurements: Head length 0.317 0.002 mm, head width
0.245 0.002 mm, head index 77, scape length 0.191 0.002,
scape index 60, funiculus length 0.296 0.003 mm, club
length 0.191 0.002 mm. Thorax length 0.336 0.004 mm, body
length 1.1 mm. The preceding measurements based on 18
specimens.
Structural characters: Head (Fig. 30) distinctly longer
than broad with weakly convex sides and straight or slightly
excised posterior border. Antennal scapes reaching 2/3 the
distance from insertions to hind corners of head. Eye reduced
to one facet, usually pigmented. In profile head somewhat
flattened dorsally, slightly convex ventrally. Anterior edge
of clypeus angularly separated from dorsal surface of mandibles
seen in profile.


SUMMARY
This study must be viewed as a preliminary effort in a neglected
area of myrmecology. No new species of Diplorhoptrum had been found in
North America since 1942. Yet a simple grid pattern of bait traps at
Gainesville, Florida, immediately captured three new species. A
fourth new species was discovered in randomized sod samples from Dade
County, Florida. Thus this group is poorly known in Florida.
The bait trap catches and ancillary studies seem to suggest
several other conclusions:
1. Bait trap sampling in the grid study varied between 53 and
75 per cent postiive for Diplorhoptrum during the summer months. All
trap locations were positive at least occasionally. The data are
consistent with information on generalized subterranean predators, which
have networks of exploratory tunnels rather than being uniformly present
in the soil. Ants that are strictly lestobiotic, always associated with
larger ants, could have been expected to show many gaps in their
distribution patterns. The data in this preliminary study suggest that
there are no distinct gaps in the subterranean spaces patrolled by
these ants.
2. Mosaic distribution patterns of the five Diplorhoptrum
species captured seem to be suggested by the data. These mosaic
patterns are similar to, if not entirely analogous with, the mosaic
patterns of arboreal ants in Ghana.
99


4
morphology may indeed be the only reliable source of characters on
which to base Diplorhoptrum taxonomy, the fact remains that at present
few of the males are known. For this reason American myrmecologists
have been reluctant to accept Baroni-Urbani's work (pers. comm., W. F.
Burn). Retaining Diplorhoptrum as a subgenus may be acceptable simply
for convenience: as a group Diplorhoptrum are usually small, mono-
morphic species as opposed to the larger, polymorphic, free-living fire
ants (MacConnell et al., 1976). All S^. (Diplorhoptrum) species have the
2nd and 3rd joints of the funiculus distinctly broader than long, whereas
in S.. (Solenopsis) and (Euopthalma) species these joints are longer than
broad.
To search the literature on Piplorhoptrum, one must be aware that
the species most frequently published upon, S^. (jL) molesta, is also
found under five synonyms: Myrmica molesta Say, Myrmica minuta Say,
Myrmica exigua Buckley, Solenopsis debilis Mayr, and Solenopsis
molesta (Say).
There has been an unfortunate tendency to identify every small
yellow thief ant as S^. (JD.) molesta. The problem is compounded by the
fact that S^. (JL) mol esta is the only economic pest in the Diplorhoptrum
group. As a result much of the literature concerning S^. (]}.) molesta
may be based on misdeterminations.
Distribution
Creicjton (1950) listed 12 taxa of Pi pi orhoptrum for North America.
The most recent compilation (Smith, 1979) also contains 12 taxa: 10 from
Creighton's original list, one species renamed, and one placed
in synonomy. At least one Diplorhoptrum species has been reported


This dissertation was submitted to the Graduate Faculty of the College
of Agriculture and to the Graduate Council, and was accepted as partial
fulfillment of the requirements for the degree of Doctor of Philosophy.
August, 1980
^ t
Dean,/'College of Agricwture
jLt'i
Dean, Graduate School


PLATE 9
Figure 33. Cluster of mating flight tumuli of S_. (j).) pergandei
Forel
Figure 34. Mating flight tumulus of S_. (CL) pergandei Forel
Figure 35. Mating flight tumulus of S. (J3.) pergandei Forel


79
Summation Values
o-300
301-600
HD 601-1,000
l,000+
Figure 39. Five month (June-Oct., 1979) summation of the
distribution by trapping of (D_.) carol inensis
in an open field at Gainesville, Florida.


28
prominent anterioventral tooth and prominent ventral swelling
(Fig. 27). From above, petiole and postpetiole nearly equal in
width. Postpetiole with rounded sides as seen from above, not
trapezoidal. Anterioventral flange of postpetiole seen in
profile sharp but very small.
Sculpture: All surfaces smooth and shining except for head
which is heavily and densely marked with prominent punctures and
dorsum of the promesonotum which is moderately marked with weaker
punctures. Head has characteristic median streak free of punc
tures.
Pilosity: Head with numerous short hairs. Thorax, petiole,
postpetiole, legs, and gaster also with numerous short hairs
which may be longer than those on the head (Fig. 1).
Color: Entirely light yellow to light yellowish brown.
Female:
Diagnosis: A rather large, dark colored female with
colorless wings. Head distinctly trapezoidal in shape. Head
and dorsum of thorax covered with numerous strong piligerous
punctures. Differs markedly from i>. (_D.) pergandei females in
color and head shape.
Description: Head length 0.78 mm, head with 0.98 mm, head
index 126, scape length 0.67 mm, scape index 86, eye length 0.24 mm,
body length 5.5 mm.
Structural Characters: Head distinctly trapezoidal, with
nearly straight hind border and sides, the head distinctly more
narrow in front than behind. Scapes not quite reaching hind


20
When anlowa S_. (D.) molesta colony was placed in a Crisco
barriered nest, however, the workers began to eat the Crisco some
thing none of the Florida species had donel The colony is presently
housed in a glass jar with a screw-top lid.
Feeding
Colonies offered a selection of foods including 1:1 honey-water,
butter, raw hamburger, peanut butter, honey-agar, oil-packed tunafish,
fire ant diet (used by USDA, Fire Ant Laboratory, Gainesville, Florida),
and mealworms. S^. (J).) carolinensis fed upon the honey-agar and tuna-
fish, but largely ignored the other foods. They backed off hurriedly
from peanut butter. Mealworm larvae were killed, but did not appear to
be fed upon.
Although Sk (£.) pi eta and Sk (JD.) reinerti accepted fire ant diet
and honey-agar readily, colonies of S^. (J3.) pergandei were reluctant
feeders on all offered foods. Fire ant larvae were also offered to
this species but were refused, even when the larvae were punctured so
that haemolymph exuded. Colonies of this species could not be main
tained for more than a few months.
Queen Colony Founding
Young, newly mated females obtained from light traps were ini
tially placed in compartmented plastic boxes. Each compartment had a
moistened plaster of paris floor and sides painted with Fluon The
high humidity allowed the queens to walk over the Fluon however,
and they congregated in groups. Of 36 S_. (]D.) carolinensis, 45 S_. (D.)
pergandei and two S_. (D..) reinerti females, eight S^. (j).) carol inensis
no S.. (j).) pergandei and both S^. (JL) reinerti queens reared brood to


SOLENOPSIS (DIPLORHOPTRUM) (HYMENOPTERA:FORMICIDAE) OF FLORIDA
By
Catherine R. Thompson
A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1980


INTRODUCTION
There are approximately 8,000 known taxa of ants in the world, and
the habits exhibited are extremely diverse (Wilson, 1971). Three
principal ecological types may be said to exist in the Formicidae.
These are: I. Arboreal species, ants which nest in trees and forage
for food or obtain their food in trees or non-aborescent plants, II.
Terrestrial ants which nest in the soil and forage for food mostly on
the soil surface, and III. Subterranean or cryptobiotic ants, ants
that nest and forage underground or beneath debris seldom coming to the
soil surface. Species may, of course, occupy more than one of these
habitats.
Cryptobiotic ants are interesting academically because they often
are highly modified structurally Ants of the generally cryptobiotic
tribes Dacetini and Basicerotini, as well as other aberrant genera,
have been described and figured in many papers, of which Brown (1962),
Brown and Kempf (1967), Brown (1974) and Brown (1977) are examples.
The highly modified structures of these ants probably adapt them for
specialized predation on soil arthropods and are fortuitously useful
in taxonomic studies.
Subterranean ants are generally thought to be lestobiotic.
Solenopsis (Diplorhoptrum) as well as related subterranean genera
such as 01igomyrmex, Carebara, Carebarella are also more generalized
in structure. They have few specialized features which makes them
1


92
also more exposed to predators by their slowness to take wing. I saw
both Pheidole workers (June 10, 1979) and a worker of Odontomachus
brunneus (Patton) on June 26, 1979, carrying off S_. (D_.) pergandei
females.
Much predation is probably avoided by the erratic movements of the
workers. The impetus of worker movements caused them to spread out by
the hundreds over the tumulus and within a radius of approximately 5 cm
around it. In this area they frequently confronted workers of other
species of ants which were immediately attacked. As a result, the large
females were protected by a network of workers within the tumulus area.
Although the activities of the workers protected the females quite
adequately, after the flight the nest was exposed to extreme danger.
The workers did not always close colony entrances and often could be
found on the soil surface until midmorning. On three occasions I ob
served a S^. (]}.) pergandei nest being destroyed by Solenopsis geminata.
I suspect that the only reason more S^. (£.) pergandei nests were not
attacked was that, after the sun reached them, the tumuli rapidly began
to crumble. By 10 a.m. it was virtually impossible to determine whether
a flight had occurred: the tumuli had crumbled to a layer of powdered
dust on the soil surface.
An unexpected observation was the number of flights which were
staged from single nests. Nest locations were stable throughout the
summer and workers constructed a new tumulus where the old one had
collapsed or had been obscured by rain. It was not uncommon for flights
to be initiated from a nest every favorable morning for two months or
more. I observed one nest from which sexuals flew for nearly the
entire summer.


PLATE 4
Figure
Figure
Figure
Figure
13. Lateral view of worker of $k (JD.) nickersoni n. sp.
(75X)
14. Head of the worker of S. (D.) nickersoni n. sp.
(120X)
15. Petiole and postpetiole of worker of S_. (JD.)
nickersoni n. sp. (420X)
16. Dorsal view of worker of S_. (D_.) nickersoni n. sp.
(65X)


31
2. Solenopsis (Diplorhoptrum) carolinensis Forel
Solenopsis texana race carolinensis Forel 1901. Ann. Soc.
Entomol. Belg. 45:345.
Solenopsis (Diplorhoptrum) carolinensis Forel. Creighton, 1950.
Bull. Mus. Comp. Zool. 104:236.
Type locality: Faisons, North Carolina
Types: Museum of Comparative Zoology, Harvard University
Range: North Carolina and Tennessee north to lower New England states
Diagnosis:
A small Diplorhoptrum with a quadrate-shaped head, moderately
sized darkly pigmented eyes. Pilosity moderate, piligerous punctures
weak. Pilosity on the head short and nearly all of the same length.
In profile, often with an anterioventral tooth on the petiole. Head
and gaster usually infuscated. Female small with large eyes.
Pi scussion:
Described as a characteristic species of North Carolina (Wheeler,
1904b) S^. (JL) carol inensis is also a common species in Florida. It is
very common in Gainesville, and was found wherever the Diplorhoptrum
fauna was sampled throughout the state. It was found in many
habitats: palmetto thickets, turkey oak, open sand areas, rocky soil
in Homestead, grassy areas, and pine woods.
The nests of this species are shallow (less than 20 cm) and
quite frequently one turn with a shovel will bring up the colony queen
with a small group of brood and workers. A colony can have more than
one queen. This species tends to forage more than most other Florida


PAGE
Section II. Subterranean Distribution of
Diplorhoptrum Species 71
Section III. The Mating Flights of S_. (jl.) pergandei ... 88
Tumuli Construction 88
Flight Factors 89
Flight and Postflight Activities 90
Section IV. The Role of S_. (Piplorhoptrum) as Underground
Predators 95
Preliminary Experiments 95
Predation on Fire Ant females 95
Predation on Diaprepes abbreviatus Larvae 96
SUMMARY 99
GLOSSARY 102
APPENDIX 104
LITERATURE CITED 105
BIOGRAPHICAL SKETCH 115
vi


2
difficult to study taxonmica11y. Whitcomb et al. (1972) and Burn
et al. (1977) suggested that this group of genera and species might be
much more important as generalized subterranean predators than had
been previously suspected, and that their role in lestobiosis might
be secondary.
These studies were undertaken as an investigation into the
abundance, ecology, taxonomy, and predatory importance of these ants
in Florida. The data will revise thinking on the importance of these
predators in the subterranean ecosystem. The study also helps to
emphasize the need for similar studies on a world-wide basis.


29
corners of the head. Eyes rather small for Diplorhoptrum females.
Ocelli also small for females of this group. Petiole with blunt
node, slightly excised above as seen from behind. Postpetiole
wider than petiole, trapezoidal as seen from above, wider
posteriorly than anteriorly.
Pilosity: Head and thorax with numerous hairs arising from
strong punctures. Gastric pilosity also abundant but not arising
from punctures. A median streak on head free from punctures or
hairs as in the worker.
Color: Head, thorax, petiole, postpetiole and gaster dark
brown. Legs and antennae light greyish yellow. Wings colorless.
Male: Unknown
Types:
Holotypea worker from Gainesville, Florida, captured with a
Naves trap (June 16, 1979). Airport area. C. R. Thompson
Paratypes--numerous specimens from Gainesville Airport area, June
through September, 1979, C. R. Thompson; three workers and one female
from Tall Timbers Research Station, Florida. June, 1975. M. A. Naves.
The holotype and several paratypes will be deposited at the
Museum of Comparative Zoology. Paratypes will also be deposited in
the Florida State Collection of Arthropods, Gainesville, Florida.
Pi scussion:
This species appears superficially close to pergandei on one hand
and to tennesseensis on the other. The female, dark in color and with


25
4a) Thorax in profile straight above; base and declivity of pro-
podeum distinguishable; head narrow and elongate, head index
79; punctures on head over entire surface, no median streak
free of punctures and hairs *tennesseensis M. R. Smith
b) Head proportionately not as narrow; head in some species with
distinct median streak free of punctures and hairs; propodeum
usually evenly rounded in profile and without distinguishable
base and declivity 5
5a) Head with obvious median streak free of punctures and hairs
(Fig. 2), in mounted specimens a median crease may also be
present in this area (but this is not evident in living or
freshly killed specimens); head elongate and narrow, head
index 89; females and males dark brown or black; head of female
trapezoidal in shape abdita n.sp.
b) Without this combination of characters; head either without
median hair-free streak, or head nearly as broad as long; head
never with median crease in mounted specimens; males and females
either light yellow or, if black, then head of female not
trapezoidal in shape 6
6a) Large species 1.8 mm in total length with head 0.429 0.009 mm
in length; head index 96; head thick and robust in profile;
shaped as in Fig. 18; males and females yellow or light
brownish yellow; wings clear and nearly colorless
pergandei Forel
b) Small species 1.1 mm in total length; head 0.318 0.002 mm in
length, head index 77; head flattened above and slender in


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RESULTS
Section I
A Taxonomic Review of the S. (Diplorhoptrum) of Florida
Introduction
No taxonomic progress has been made in the Solenopsis (Diplorhoptrum)
group for a number of years. The most recent species to be described
was S^. (jD.) longiceps by M. R. Smith in 1942. This species name was
subsequently found to be preoccupied by Solenopsis longiceps Forel, and
was changed to _S. (D.) tennesseensis M. R. Smith in 1951. The most
recent taxonomic key for the group is that by Creighton (1950) in which
he tried to define the group and synonymized several names.
Because of taxonomic and identification difficulties, most workers
have been lumping any Diplorhoptrum specimen under S_. (D.) molesta.
This species, in fact, is supposed to occur in Florida, but I have not
collected it anywhere in the state. The situation is not improved by
the fact that all of Say's types, including those of S^ (£.) mol esta
(Say), have been lost.
When a small, 100-meter square area in Gainesville was sampled and
three new species were frequently recovered, it was very apparent that
taxonomic work was needed. This study will help to prevent the "band
wagon" effect, which has gone on for many years, of labeling any
Diplorhoptrum specimen molesta. It will fill the gap left by Van
Pelt (1947) who purposely omitted the group from his Florida key
because of their uncertain taxonomy.
22




REVIEW OF LITERATURE
Taxonomy
The genus Solenopsis is essentially cosmopolitan and is found in
all but the coldest parts of the world. The genus was divided by
Creighton (1950) into three subgenera: Solenopsis, Euopthalma and
Diplorhoptrum. The painful stings inflicted by members of the
Solenopsis (Solenopsis) group have attracted public attention as the
red Imported Fire Ant Solenopsis invicta Burn continues to spread in
the southern and southwestern U.S.
While not endearing themselves to the general public, the genus
Solenopsis is also no favorite of ant taxonomists. Creighton (1950)
grumbled "The student of North American ants may count himself fortunate
that so few species of this difficult genus occur in our latitudes"
(p.226). The worker caste in Solenopsis has undergone extreme con
vergence, making identification to species difficult. Unfortunately
most of this convergence has occurred in Diplorhoptrum.
The taxonomic postion of Diplorhoptrum is subject to discussion.
Ettershank, in his revision of the Solenopsini (1966), synonymized
Diplorhoptrum under Solenopsis. Baroni-Urbani (1968) resurrected the
group and gave it full generic status. Unfortunately he based his
determination on the male genitalia of the common European species,
S_. (.D.) fugax (Latreille), without knowledge of the Neartic and Neo
tropical fauna. Although Creighton suspected that male and female
3


27
1. Solenopsis (Diplorhoptrum) abdita n.sp.
Diagnosis:
Workers pale colored, and densely covered with short hairs. Head
strongly marked with prominent punctures but with a clear median streak
free of piligerous punctures. Eyes reduced to one facet, inconspicuous.
Head broader in proportion to length than in tennesseensis, and thorax
more convex in profile. Females large and dark colored, the head
uniquely trapezoidal in shape. Wings colorless. Head and thorax with
numerous piligerous punctures.
Description:
Worker:
Measurements: Head length 0.361 0.004 mm; head width
0.32 0.002 mm, head index 89, scape length 0.235 0.003 mm,
scape index 65. Thorax length 0.444 0.003 mm, total body
length 1.56 mm. The preceding'measurements based on nine
specimens.
Structural Characters: Head longer than wide, rectanguloid
with faintly convex sides, the posterior border slightly excised
in the center. In some specimens the head is slightly more
narrow anteriorly. The eyes reduced to a single facet. Ventral
border of head moderately convex in profile. Anterior edge of
clypeus widely and angularly separated from dorsal surface of
mandible in profile. A flat head (Fig. 25) not present.
Promesonotum of thorax weakly convex in profile, propodeal
base somewhat more convex. Petiole large in profile with a


BIOGRAPHICAL SKETCH
Catherine R. Thompson was born November 21, 1952, in Boston,
Massachusetts. Her family moved to Cedar Falls, Iowa, where she
attended Malcolm Price Laboratory School. In June, 1971, she graduated
from Northern University High School in Cedar Falls.
She attended the University of Northern Iowa in Cedar Falls,
during the summers of 1971, 1972, 1973 and the fall of 1973. She
attended Cornell College during the remainder of 1971, 1972, 1973 and
part of 1974, graduating in June, 1974, with a B.A. in biology and
English.
In September, 1974, she entered graduate shcool in the Depart
ment of Entomology and Nematology at the University of Florida. She
received the M.S. degree in June, 1976, and commenced work'toward the
Doctor of Philosophy degree in entomology and a minor in botany at the
University of Florida.
115


43
8. Solenopsis (Diplorhoptrum) reinerti n.sp.
Diagnosis:
A small pale species. Eyes small but darkly pigmented. General
characters of workers similar to carolinensis, but queens dark in
color except for pale appendages, with small eyes and ocelli.
Description:
Worker:
Measurements: Head length 0.336 0.003 mm, head width
0.285 0.003 mm, head index 85, scape length 0.225 0.003 mm,
scape index 67, funiculus length 0.332 + 0.006 mm, club length
0.207 0.004 mm. Thorax length 0.359 0.004 mm, body length
1.58 mm. The following measurements based on 12 specimens.
Structural characters: Head quadrate, longer than broad
with weakly convex sides and straight posterior border. Eyes
small but pigmented, with two or three facets. Mandibles with
four teeth.
Thorax similar in structure to carolinensis. Propodeum
smoothly rounded in profile without definite base or declivity.
Petiole similar in shape to that of carolinensis but without
ventral concavity and the anterioventral teeth characteristic
of carolinensis (Fig. 27). Postpetiole a little wider than
petiole seen from above and weakly trapezoidal as in
carolinensis. Postpetiole shorter in proportion to length
than in carolinensis.


6
damaged. Early planting, along with seed treatment, fall plowing, and
surface planting have essentially eliminated the kafir ant problem.
Su (D.) molesta has been reported to eat out the interiors of corn
kernels, and in New York is known as the "little yellow ant" (Fitch,
1856) and the "yellow field ant" (Felt, 1916). There are reports of
strawberries (Fitch, 1920) and blackberries (Webster, 1893) damaged by
S^. (D_.) molesta. This ant may also indirectly damage crops through its
habit of tending various species of aphids (Landis, 1967; Smith &
Morrison, 1916; Webster, 1893). It attacked the cocoons of the Japanese
beetle parasite Tiphia and killed 20% in the laboratory (White, 1940).
Smith (1965) reported S_. (D.) molesta as a host of a poultry tapeworm.
S. (D.) molesta is one of only two of our native ant species which
invades homes (Wheeler, 1910). Herrick (1921) reported on the "little
fiery ant" which invaded kitchens. While Forbes (1896, 1920) and
Fitch (1856) stated that this ant had a sweet tooth, Back (1937) said
that it fed "almost entirely" on greasy substances. It is possible that
a number of Diplorhoptrum species may be involved. _S. (D.) molesta
validiuscula Emery is a common pest in California homes where it lives
in crevices around sinks and feeds on greases, meats, and cheese
(Mal lis, 1941). Among the more curious of S_. (D^.) molesta dietary
preferences was an insect collection (Fitch, 1856) while an
artist complained that _S. (£.) molesta was eating his paints (Webster,
1893).
Nearly as many reports in the literature point to S_. (CL) molesta
as a valuable predator as malign this species as an economic pest.
Brooks (1906) observed S^. (£.) mol esta in large numbers feeding on
grape curculio, Craponius inaegualis (Say), larvae. The ant killed


23
The four new species found during this study have the proposed
names of (JD.) "abdita11 n.sp., S_. (£.) "nickersoni11 n.sp., S_. (CL)
"reinerti" n.sp. and S.. (JL) "xenovenenum" n.sp. (Names proposed here
in quotation marks are not to be considered validly or effectively
published for nomenclatura! purposes.)


MATERIALS AND METHODS
Taxonomy
Because the largest Florida S. (Diplorhoptrum) worker is only
1.8 mm long, it is imperative that anyone wishing to study this group
have at their disposal a microscope with a minimum of 40 diameters of
magnification. The Wild microscope used for this study was also
equipped with an ocular micrometer.
Traditional measurement techniques were utilized and specimens
were compared with types at the U.S. Natural History Museum in
Washington, D.C., and the Museum of Comparative Zoology at Harvard
University, Cambridge, Mass. Measurements of specimens and indexes
calculated were as follows:
1. Head width: greatest width of the head in full face view.
2. Head length: greatest length of the head in full face
view, but excluding the mandibles.
Head width x 100
3. Head index:
4
Head length
Head depth: measured on line running through the eye and
perpendicular to line running from just above mandibular
insertion to point where neck meets thorax.
5. Thoracic length: greatest length of thorax in lateral view.
6. Scape length: middle of antennal socket to tip of scape.
7. Scape index: ^ f?th 100 .
K Head length
8. Funiculus length: tip of scape to tip of funicular club.
12


50
Thorax weakly convex; propodeum rounded without definite
base or declivity (Fig. 29). Petiole without anterioventral
tooth. From above the petiole and postpetiole are about the
same width. Postpetiole with rounded sides.
Sculpture: Dorsum of head covered with distinct punctures
but these not as strong as in tennesseensis or abdita. Dorsum
of promesonotum also with some weak punctures. All other
surfaces smooth and shining.
Pilosity: Hairs short and numerous on all surfaces.
There may be some longer hairs on the thorax, gaster, and petiole.
Color: Yellow to pale yellowish brown.
Female:
Measurements: Head length 0.59 mm, head width 0.64 mm, head
index 108 mm, scape length 0.46 mm, scape index 78, funiculus
length 0.60 mm, total body length 3.24 mm.
Structural characters: Head quadrate, a little longer than
broad with both sides and occipital border nearly straight or
only slightly convex. Scapes nearly reaching hind corners of
the head. Ocelli rather small, measuring 0.02 mm in diameter
and separated from each other by at least one diameter.
Thorax slightly narrower than head. Petiole without
anterioventral tooth. Node of petiole with slightly excised
superior border seen from behind. Petiole and postpetiole of the
same width. Postpetiole weakly trapezoidal as seen from above,
wider posteriorly than anteriorly.


74
t3S_. (D_.) carol inensi s
S_. (JD.) abdita n. sp.
(D_.) xenovenenum n. sp.
Figure 38. Diplorhoptrum species captured by Naves trap in
a long leaf pine-turkey oak woods at Gainesville,
Florida, from June 1979-1980.


PLATE 1
Figure 1. Lateral view of worker of S.. (D^) abdita n. sp.
(65X)
Figure 2. Head of the worker of (J).) abdita n. sp.
(120X)
Figure 3. Petiole and postpetiole of worker of (D.)
abdita n. sp. (340X)
Figure 4. Dorsal view of worker of S_. (D^.) abdita n. sp.
(50X)


TOO
3. Diplorhoptrum species are able to kill and dismember in
sects much larger than themselves, like large Lepidoptera larvae,
fire ant queens, and Coleptera larva. This is probably due to the
potency of their venoms. These data again are consistent with wide
spread generalized predators, rather than with specialized predation as
exhibited by other cryptobiotic ants such as Strumigenys and Smithistruma.
The generalized morphological structure of Diplorhoptrum species is also
consistent with that of generalized predatory ants, as contrasted with
the highly specialized morphologies of the Dacetine ants.
4. Perhaps the most important finding that arises from this study
is the significant lack of general biological knowledge of these ants.
The ants were previously thought to be specialized, lestobiotic species
with sporadic distributions, yet they are now shown to be generalized,
widespread, abundant predators in Florida. An important question is
whether or not these or other similar ants have similar roles in other
areas of North America and of the world. If there is a network of sub
terranean ants on a worldwide or very widespread basis, then an important
component of ecosystems has been neglected.
The paucity of knowledge about Piplorhoptrum is nowhere better
seen than in the mating flight data. In spite of much observation,
S.. (_D.) pergandei mating flights were the only flights seen. The other
species apparently never construct tumuli. How their sexuals are brought
to the surface and what factors trigger their flights is unknown. It is
presumed that those species with dark colored sexuals with small eyes
and ocelli are diurnal flyers, while species with yellowish sexuals with
large eyes and ocelli are nocturnal flyers.


PLATE 7
Figure 25. Lateral view of worker of (J3.) reinerti n. sp.
(90X)
Figure 26. Head of the worker os (DL) reinerti n. sp.
(140X)
Figure 27. Petiole and postpetiole of worker of S^. (13.)
reinerti n. sp. (460X)
Figure 28. Dorsal view of worker of S^. (J3.) reinerti n. sp.
(50X)


14
3. The specimens were heated an additional two minutes
then were cooled 10 minutes.
4. A ring of "zut" (Thorn, 1935), a sealant used to mount
helminths, is placed on a slide. The ring is built up
enough to avoid crushing the specimens (and requires practice
and extra specimens). The ants, in some lactophenol
solution, are placed in the ring and a cover slip placed
over the ants and the zut.
Having a number of ants per slide ensured that at least one would be
positioned correctly for any structure studied.
Scanning Electron Micrography
Diplorhoptrum workers are so small that use of the usual black
carbon contact cement was nearly impossible. Split-second timing was
needed, otherwise the cement dried or the specimen disappeared under
the cement.
These problems were overcome by the use of double-stick white
labels. The ants were arranged on the label and pushed into the ad
hesive. But a problem developed with charging (a process which results
in bright light bouncing off the specimen and obscuring structure),
even though the specimens had been double-gold-coated at three minutes
per coat with a break between coatings to dissipate heat.
To alleviate charging, the ants were placed on the sticky labels
and spots of carbon glue were placed near the specimens and smeared
into contact with the tarsi or under parts of the body. In this way
conduction was increased and charging reduced.


PLATE 2
Figure 5
Figure 6
Figure 7
Figure 8
Lateral view of worker of (JD.) carol inensis
Fore! (60X)
Head of the worker of S^. (]).) carol inensis Forel
(130X)
Petiole and postpetiole of worker of S_. (£.)
carolinensis Forel (290X)
Dorsal view of worker of ([).) carolinensis Forel
(56X)


85
51
A
21
31
E
30
m
31
E
52
e
f!
m
22
E
39
m
32
E
53
AE
63
23
"
E
33
34
A E
32
E
24
2
32
m
34
55
A
6B
25
2
33
E
35
E
55
ss
2t
e
35
E
36
E
s'
S4
E
22
E
34
B
32
E
51
E
S3
E
21
E
33
E
33
E
ss
E
B
A E
23
A
32
E
33
E
st
A
"
A B
11
A E
"
E
111
E
/~\S_. (ID.) carol i-
w nensis
/\ S. (JD.) abdita
ii S_. (ID.) xeno-
1I venenum
Figure 45. Number of months each trap site in a long leaf pine-
turkey oak woods at Gainesville, Florida, was positive
for three species of Pi piorhoptrum (June 1979-June 1980).


106
Brown, W.L. 1977. An aberrant new genus of Myrmicine ant from
Madagascar. Psyche 84:218-224.
Brown, W.L. and W.W. Kempf. 1967. Tatuidris, a remarkable new genus
of Formicidae (Hymenoptera). Psyche 74:183-190.
Browne, J.T. and R.E. Gregg. 1969. A study of the ecological distri
bution of ants in Gregory Canyon, Boulder, Colorado. Univ. of
Colorado Studies, Series in Biol. 30:1-48.
Brues, C.T. 1903. Descriptions of new ant-like and myrmecophilous
Hymenoptera. Trans. Amer. Entomol. Soc. 29:119-128.
Bryson, H.R. 1941. The occurrence in Kansas of the sugar-cane root-
stock weevil, Anacentrinus deplantus Csy. (Coleptera,Curculioni-
dae). J. Kansas Entomol. Soc. 14:84-90.
Buckley, S.B. 1866. North American Formicidae. Proc. Entomol. Soc.
Philadelphia 7:335-350.
Burn, W.F., M.A. Naves, and T.C. Carlysle. 1977. False Phragmosis
and apparent specialization for subterranean warfare in Pheidole
lamia Wheeler (Hymenoptera:Formicidae). J. Georgia Entomol. Soc.
12:100-108.
Burkhardt, C.C. 1959. Increasing sorghum stands in field tests by
controlling thief ants and other insect pests. J. Econ. Entomol.
52:365-368.
Carter, W.G. 1962a. Ants of the North Carolina Piedmont. J. Elisha
Mitchell Sci. Soc. 78:1-18.
Carter, W.G. 1962b. Ant distribution in North Carolina. J. Elisha
Mitchell Sci. Soc. 78:150-204.
Chew, R.M. 1977. Some ecological characteristics of the ants of a
desert-shrub community in southeastern Arizona. Amer. Midland
Natur. 98:33-49.
Cole, A.C., Jr. 1933. Ant communities of a section of the sagebrush
semi-desert in Idaho, with special reference to the vegetation
(Hymenop.:Formicidae). Entomol. News 44:16-19.
Cole, A.C., Jr. 1936. An annotated list of the ants of Idaho
(Hymenoptera:Formicidae). Can. Entomol. 68:34-39.
Cole, A.C., Jr. 1940. A guide to the ants of the Great Smoky Moun
tains National Park, Tennessee. Amer. Midland Natur. 24:1-88.
Cole, A.C., Jr. 1942. The ants of Utah. Amer. Midland Nat. 28:
358-388.
Collins, H.L. and G.P. Markin. 1971. Inquilines and other arthropods
collected from nests of the Imported Fire Ant Solenopsis saevissima
richteri. Ann. Entomol. Soc. Amer. 64:1376-1380.


46
9. Solenopsis (Diplorhoptrum) tennesseensis M. R. Smith
Solenopsis (Diplorhoptrum) longiceps M. R. Smith, 1942. Proc.
Entorno!. Soc. Wash. 44:210. Preoccupied by Forel,1907.
Solenopsis (Diplorhoptrum) longiceps M. R. Smith. Creighton,
1950. Bull. Mus. Comp. Zool. 104:236-236.
Solenopsis (Diplorhoptrum) tennesseensis M. R. Smith, 1951.
In Muesebeck, U.S.D.A. Agr. Monog. 2:814. N. name.
Type locality: Hamilton Co., Tennessee.
Types: United States National Museum, Washington, D. C.
Range: Florida west to Texas and north to latitude of Tennessee.
Diagnosis:
We did not find this subterranean species in Florida in spite of
previous records. It has probably been confounded with the new species
S.. (D.) xenovenenum. S^. (j3.) tennesseensis is unusual in having a
slender head. The thorax in profile is straight dorsally and the
propodeum has a distinct base and declivity. Head and thorax with
numerous short hairs arising from distinct punctures. It differs from
.S* (JD.) abdita in not having a clear median streak free from punctures
and hairs on the head.
Discussion:
This study has shed no new light on the biology or distribution
of S^. (D.) tennesseensis. Little information is present in the
literature. This species is known primarily from the type series.
The range given by Creighton (1950) may not be accurate.


48
11. Solenopsis (Diplorhoptrum) truncorum Forel
Solenopsis texana race truncorum Fore!, 1901. Ann. Soc.
Entorno!. Belg. 45:346.
Solenopsis molesta var. castanea Wheeler, 1908. Bull. Amer.
Mus. Natur. Hist., 24:430.
Solenopsis (Diplorhoptrum) truncorum Creighton, 1950. Bull.
Mus. Comp. Zool. 104:239.
Type locality: Faisons, North Carolina
Types: Museum d'Histoire Naturelle, Geneva, Switzerland.
Range: Southeastern U.S. and west to the Rocky Mountains.
Diagnosis:
A large, dark-colored species with rather sparse scattered hairs
of mixed lengths. This species is common in the mountains of the
western U.S., but also occurs in the eastern Appalachian Mountains.
Discussion:
The large dark brown castanea was synonymized under truncorum
by Creighton (1950). No types of truncorum are present in this country,
but the types of castanea were compared with various Florida species
by Dr. William F. Burn. The Florida specimens did not match the
types of castanea.
I have not found this species in Florida, although Smith (1979)
lists the species as occurring in this state.


5
from each of the contiguous 48 states with S_. (_D.) molesta (Say), the
most widespread species, reported from 30 states. The species reported
from Florida are S_. (J3.) molesta (Say), S_. (j).) pergandei Forel,
S_. (D.) pi eta Emery, S_. (_D.) tennesseensis Smith, S_. (£.) texana Emery,
and S_. (jD.) truncorum Forel.
Economic Importance
Although not as notorious as their fire ant relatives, Diplorhoptrum,
or thief ants as they are commonly called, contains one species,
Solenopsis (Diplorhoptrum) molesta (Say), which is a pest in fields and
dwellings. As a result of this pest status, and erroneous identifi
cations, most of the literature deals with this species. Although
Creighton (1950) reported it to be distributed only in the central and
eastern states, it has subsequently been reported from eight of the 11
western states (Appendix).
S_. (£.) molesta is best known as a economic pest of sorghum.
The ant is known as the "kafir ant" in Kansas (Bryson, 1941; Hayes,
1925) where it has been called the single most damaging pest of planted
sorghum (Burkhardt, 1959). The ants diminish sorghum stands by feeding
on germinating sorghum seed (Young and Howell, 1964). They have
destroyed thousands of acres of sorghum necessitating one to six
replantings and then not always with a resultant full stand (McColloch
and Hayes, 1916). Srivastava and Bryson (1956) found that tilling the
soil, planting early, and using various insecticides or insecticide-
fungicides prior to planting helped avoid damage. All of the com
pounds tested were effective, while the ants damaged 50% of the check
seeds. McColloch and Hayes (1916) found that only late plantings were


40
6. Solenopsis (Diplorhoptrum) pergandei Fore!
Solenopsis pergandei Forel, 1901. Ann. Soc. Entomol. Belg.
45:343.
Solenopsis (Diplorhoptrum) pergandei Fore!. M. E. Smith, 1947.
Amer. Mid. Natur. 37:568.
Solenopsis (Diplorhoptrum) pergandei Forel. Creighton, 1950.
Bull. Mus. Comp. Zool. 104:237.
Type locality: Faisons, North Carolina.
Types: Museum d' Histoire Nature!le, Geneva, Switzerland. None in this
country
Range: Virginia and south to Florida, west to Louisiana.
Diagnosis:
This clear-yellow Diplorhoptrum is the largest species of this
subgenus in Florida. The worker is approximately 1.8 mm long while
the large females are 5.5 mm long. It also differs from other Florida
species in its robust head and thorax. Piligerous punctures on
head numerous and distinct. Head quadrate, only a little longer
than broad, convex dorso-ventrally in profile.
Discussion:
This species is common in Florida, and was found over the entire
state. It does not leave any surface indication of its nests except
during May through August in Florida when it constructs crenelated
tumuli the night before a mating flight (see Section 2).
This ant prefers to nest in areas which are quite dry and where
the soil is compacted such as lawns and woods trails. I have found it
in large numbers under a baseball diamond in full midday sun. In


32
species in the forest duff, and I have seen It tending mealy bugs.
Excavations of an S^. (J).) pergandei colony will often bring
(D.) carolinensis to light in the same shovelfull. The larvae of
S_. (JD.) carol inensis have a pinkish cast and are smaller than those of
S_. (JD.) pergandei.
The mating flights of this species have not been observed, but I
have dug sexual brood in June (6/9/79) and the flights occur during the
same months (June through August) as those of S.. (ID.) pergandei. The
sexual s of JJ. (JD.) carol inensis are attracted to light traps, but in
smaller numbers than JL (JD.) pergandei. The sexuals of S_. (JD.)
carolinensis fly earlier in the morning (5-5:30 a.m.).
I suspect that the Florida (JD.) molesta records, and one of
SJ. (D.) laeviceps (Smith, 1930), are based on mis identified specimens
of S^. (JD.) carolinensis. Types of this species at the Museum of
Comparative Zoology have been examined by Dr. William F. Burn.


71
Section II
Subterranean Distribution of Diplorhoptrum Species
Mosaic distribution of ant species is well documented in cacao
plantations (Majer, 1972; Leston, 1973), but these studies involved
arboreal species in easily sampled ecological niches, i.e., cocoa trees.
Nothing was known of the distribution of Diplorhoptrum species below
ground, particularly as no surface structures are constructed by these
ants, with the exception of (j).) pergandei mating flight tumuli.
Accordingly, 5x10 meter grids were set up, and experimental
trapping was begun in June, 1979. The results were immediate and
surprising. Of 100 traps put down June 17, in 24 hours 59 were positive
for ants and, of these, 43 contained Diplorhoptrum. Diplorhoptrum were
captured in as many as 75 per cent of the traps during July and August
and as few as 3 per cent in January. Some traps contained over 300
ants. An example of the results is shown in Fig. 36 for the longleaf
pine-turkey oak woods. Five species of Diplorhoptrum were captured in
the traps during this study. All were present in the first set of
traps put down on June 17. Numbers of traps in which each Diplorhoptrum
species was captured throughout the year are presented in Figs. 37 and
38.
It is evident that S.. (D.) carol inensis was the dominant subterran
ean ant in both habitats. S_. (]D.) pergandei was absent from the field
habitat, and present at only two trap locations in the woods grid. Si. (D.)
xenovenenum also had a distinct pattern in that they were captured in
only 2 traps in the field, but were evenly distributed in the wood.


16
These collections were in different habitats, the first two areas
were xeric while the third area was hydric.
Naves Traps
Naves traps (unpublished technique) were baited with honey agar
(Bhatkar and Whitcomb, 197C), cabbage loopers, Diaprepes beetle larvae,
Fire Ant queens (£. invicta), or most often tunafish. The Naves trap
is made by modifying a two ml sidetabbed Dispobeaker (Scientific
Products) as follows: A teasing needle is heated and used to melt
0.5-0.9 mm diam. holes in the cap and bottom of the beaker. Three
holes are placed in the cap top, six around the sides of the cap and
three in the bottom of the trap body. All attempts to further
standardize hole size by wiring a soldering iron with 1/16 inch
copper wire failed; the wire would not hold enough heat to melt the
plastic. Acrylic red yarn tied around the trap under the side tabs
served as a marker and means of pulling the trap from the ground.
A narrow bladed trowel (5 cm at greatest width) was used to
bury the traps with their bases at a depth of 14 cm. It was found that
less than 10 cm depths resulted in traps filled with fine sand which
sifted through the trap tops in dry soils. Depths of 18 cm or more
made trap recovery and replacement of the soil difficult. The 14 cm
depth was chosen as an average and employed throughout trapping ex
periments as an experimental constant.
As a note of caution, even the small holes of these traps did not
exclude a number of other ant species: Pheidole metal!escens Emery,
Brachymyrmex depilis Emery, Pheidole dentata Mayr, and P. floridana
Emery. Other less frequent species were Ponera pennsylvanica Buckley


86
that the ants do not forage far from the nest in the cold, it should be
possible to map nest locations more accurately than at other times of
the year.
When the winter distribution maps were prepared, however, it was
found that many traps were positive, but only once or twice, making
pattern discernment impossible.
Figures on the distribution of :S. (]}) pergandei and S^. (JD.)
nickersoni were not included, as these species were extremely localized.
5L (J).) pergandei appeared only in woods traps with one established
nest in or near Meter 70, which included territory in Meters 69-72.
S_. (JD.) pergandei is a sub-dominant. It successfully excluded SL (JD.)
carolinensis from Meter 70 for an entire year. SL ([).) nickersoni
appeared to have an even more scattered distribution except for captures
by Traps 8 and 13. It is also a sub-dominant, able (Fig. 40) to
exclude S^. (D.) carol inensis from Meter 8, but not S_. (I).) abdita.
Only Diplorhoptrum species were taken from the field traps in this
study, but other ant genera came to the woods traps: Pheidole dentata,
Pheidole floridana, Pheidole metallescens, Brachymyrmex depilis and (one
collection) Solenopsis geminata. Records of these ants were kept but
are not included in this study. It is evident from the approximately
3 to 14% of the traps which captured this group, that the greatest
competitors Diplorhoptrum have among other ants are species of Pheidole.
In summary, totally unexpected and extremely large numbers of
workers of five Diplorhoptrum species were found in an open field and in
long leaf pine-turkey oak woods. Three of the species were new. By
constructing a system of assumptions and by summing numbers of positive
traps and percentage of those traps for each species, diagrams of


FIGURE
PAGE
19 Petiole and postpetiole of worker of (JD.) perqandei
Forel (165X) 62
20 Dorsal view of worker of (JD.) pergandei Forel (75X). 62
21 Lateral view of worker of Su (D.) picta Emery (70X) ... 64
22 Head of the worker of S^. (JD.) picta Emery (140X) .... 64
23 Petiole and postpetiole of worker of (13.) picta
Emery (378X) 64
24 Dorsal view of worker of S. (JD.) picta Emery (70X) ... 64
25 Lateral view of worker of S^. (JD.) reinerti n.sp. (90X). 66
26 Head of the worker of S-. (JD.) reinerti n.sp. (140X) ... 66
27 Petiole and postpetiole of worker of S^. (ID.) reinerti
n.sp. (460X) 66
28 Dorsal view of worker of S^. (D.) reinerti n.sp. (50X) . 66
29 Lateral view of worker of S. (D.) xenovenenum n.sp.
(83X) 68
30 Head of the worker of S.. (ID.) xenovenenum n.sp. (150X). 68
31 Petiole and postpetiole of worker of S^. (JD.)
xenovenenum n.sp. (460X) 68
32 Dorsal view of worker of S_. (JD.) xenovenenum n.sp. (84X). 68
33 Cluster of mating flight tumuli of S^. (JD.) pergandei
Forel 70
34 Mating flight tumulus of S^. (JD.) pergandei Forel 70
35 Mating flight tumulus of S^. (D.) pergandei Forel 70
36 Example of Naves trap samples of Diplorhoptrum and other
species distribution in a long leaf pine-turkey oak woods
on June 24, 1979, at Gainesville, Florida 72
37 Diplorhoptrum species captured by Naves trap in an open
field at Gainesville, Florida, from June 1979-June 1980 73
38 Diplorhoptrum species captured by Naves trap in a long
leaf pine-turkey oak woods at Gainesville, Florida,
from June 1979-June 1980 74
viii


81
Summation Values
(ZDo-300
0301-600
ED 601-1 ,000
[11 ,000+
Figure 41. Five month (June-Oct., 1979) summation of the
distribution by trapping of S_. (D_.) carol inensis in
a long leaf pine-turkey oak woods at Gainesville,
Florida.


36
5. Solenopsis (Diplorhoptrum) nickersoni n.sp.
Diagnosis:
A small dark species similar to (_D.) carol inensis in head
shape, eye characteristics, thorax, and petiole shape. Antennae and
legs pale-colored and strongly contrasting with body color.
Description:
Worker:
Measurements: Head length 0.345 0.003 mm, head width
0.30 0.002 mm, head index 86, scape length 0.241 0.003,
scape index 70, funiculus length 0.359 0.004 mm, club
length 0.222 0.002 mm. Thorax length 0.384 0.004 mm,
body length 1.2 mm. The preceding measurements based on 18
specimens.
Structural characters: Head longer than broad (Fig. 14),
rectanguloid, with weakly convex sides and straight posterior
border. Head in profile with a narrow angle between the
clypeus and mandibles. Head in profile moderately flattened.
Eyes dark in color with 2-3 facets, similar to carolinensis.
Thorax in profile (Fig. 13) with moderate meso-propodeal
suture, the dorsal outline similar to carolinensis. Petiole in
profile similar to carolinensis (Fig. 7). Petiole usually
without anterioventral teeth. From above, node of petiole a
little narrower than postpetiole. Postpetiole with trapezoidal
shape as in carolinensis. In profile postpetiole with sharp
anterioventral flange (Fig. 15).


64


21
the worker stage. No (D_.) pergandei queen was able to found a
colony. Some queens laid eggs and had larvae, but died before workers
were reared.
Other materials and methods were then tried:
1. Glass tubes with moistened cotton.
2. Aged plaster of paris bottomed vials with soil above the
plaster and black paper for cover.
3. Cores of grass sod placed in vials, allowing excavation and a
more natural environment.
4. Placement in queenless laboratory colonies.
Methods 1-3 were unsuccessful. Method 4addition of queens to
queenless colonies--ended inconclusively. The females were initially
seized by the legs and antennae, but subsequently were released and
allowed to stand over the brood. Of 12 females added, six had died
before the colony had to be left unattended for two weeks. The colony
died during that time.
In summary, no satisfactory method was found for inducing queen
colony foundation in S^. (£.) pergandei. Presenting young queens with
brood or callows of their species will probably prove to be the
most useful method.
Queens of S_. (JL) carol inensis found colonies readily in plaster
of paris cups if they are allowed to remain together in groups. Queens
of S. (D..) reinerti founded colonies easily alone. It was, in fact,
the unexpected yellow workers reared by these black queens that first
convinced me that they were a new species.


78
diffuse colonies. Dr. J. C. Nickerson collected a colony of S_. (£.)
carolinensis which had 6 queens. In the laboratory a number of 2- (2-)
carolinensis queens will found a nest together amicably, and will
remain together without-fighting after workers are reared. These data
support the low energy--small queens hypothesis.
A second method of data analysis undertaken was a breakdown of
positive trap counts by month of the year as shown in Figs. 44 and 45.
Concentrations and suspected nest locations generally coincided with
those obtained from the summation method. Comparisons must be made
with caution, however, as data presented in Figs. 44 and 45 cover a
year while Figs. 39-43 include data from a five month period.
The greatest weight was placed on the five month summation study
results, after the tremendous fluctuations in species location data
were noted. Fluctuation in colony locations was greatest following the
relative inactivity of the winter months. Twenty traps remained
positive for the same Diplorhoptrum species over the entire year.
Intramonthly repeatability (June to Oct.) was high: 90% + 2.0, while
intermonthly repeatability was substantial: 63% + 3.0. The number of
traps common to the same species on June 17, 1979 and June 18, 1980
(first and last experimental dates) was eight, while the number of
corresponding traps with different species was 11 and the remaining
traps were positive on only one day or not at all.
In addition to the summation and by^month analyses of Diplor
hoptrum distribution, a third method was proposed based on the
following observations and hypothesis: during November through
February, Diplorhoptrum activity was low, with S. (D.) pergandei and
S. (D.) abdita activity ceasing entirely. If one makes the assumption


90
flight on September 3, 1979, were 0.05 fc with the probe at ground
level facing the sky, 1.0 fc facing the eastern horizon, and 1.6 fc at
45 to the horizon.
As an alternative to direct light readings, the flight times were
recorded and compared with local sunrise times (Fig. 46). Actual
flight times recorded were few. I attempted to watch 10-30 nests and
rarely saw the actual beginning of a nest flight. It was also so dark
that a flashlight had to be used to observe flight activity. It was
turned on for a few seconds every five minutes to ascertain flight
activity while attempting to keep interference to a minimum. I did
notice that I was able by summer's end to arrive at 5:45 a.m. and not
miss any of the flights. The graph in Fig. 46 does indeed show a corre
lation of flight times with time of sunrise. As the days shortened,
the flights occurred later in the morning and remained at ca. one half
hour before dawn. The occurrence of the wood flights, where dawn was
slow to penetrate, at later times than the open meadow flights, also
points to light as a triggering factor.
Flight and Post Flight Activities
When moisture and light levels are favorable, a final unknown
stimulus (or stimuli) causes the workers in a S_. (D.) pergandei nest to
begin running about erratically. The winged sexuals become excited and
begin to leave the nest. No nest was observed to contain both sexes.
Rather, only winged males or winged females were present. The nests
containing winged males began flight first. The males, with their
smaller and lighter bodies, were quickly in flight. In nests with
females flight times were longer. The larger, ponderous females were


13
9. Club length: length of last 2 antennal segments which
form the typical club.
10. Body length: total length of specimen from mandibles to
tip of the gaster. This measurement cannot be made as
accurately as the others. Specimens were so rarely in a
natural position on the pins that only a rough estimate
was made of total body lengths.
Eye length: greatest length of the eye.
11
12
Eye index- ^e_length x 100
tye inaex. Head length
Specimens studied were obtained from as many locations as possible
in Florida. Series collected by 0. P. Wojcik (USDA, Gainesville,
Florida) and by A. F. Van Pelt (collections in the Florida State
Collection of Arthropods, Gainesville, Florida) and Dr. William F.
Burn (Dept, of Entomology and Nematology, Univ. of Florida, Gainesville,
Florida) were studied.
Lactophenol Fixation
A novel method for taxonomic study of ants was use of slide-
mounted specimens prepared by a four minute lactophenol fixation pro
cess (Esser, 1973) initially developed for nematode studies. This
rapid procedure cleared specimens and allowed particularly detailed
study of pubescence.
1. The ants were removed from alcohol and placed in water in a
watch glass set inside a petri dish on a hot plate.
2. The specimens were heated to 370C and lactophenol added
until the watch glass was full.


56


PLATE 5
Figure 17. Lateral view of worker of S_. (J3.) pergandei Forel
(79X)
Figure 18. Head of the worker of S.. (jD.) pergandei Forel
(98X)
Figure 19. Petiole and postpetiole of worker of S^. (]3.)
pergandei Forel (165X)
Figure 20. Dorsal view of worker of S_. (JD.) pergandei Forel
(75X)


38
The holotype and several paratypes will be deposited at the
Museum of Comparative Zoology. Paratypes will also be deposited in
the Florida State Collection of Arthropods, Gainesville, Florida.
This species is named in honor of Dr. J. C. Nickerson, Division
of Plant Industry, Gainesville, Florida. Dr. Nickerson, over a period
of several years, has greatly aided and encouraged me in my
myrmecological studies.
Discussion:
([).) nickersoni is readily distinguished from all other Florida
ants of this genus by its dark color which contrasts with the light
color of its antennae and legs. In structure it is similar to
carolinensis including head shape, eye prominence, thoracic shape, and
petiole and postpetiole shape. It lacks the prominent head punctures
which are typical of pergandei, abdrta, and xenovenenum n.sp.
This species has been found in Florida at Gainesville, Ocala,
Apopka and .Myakka State Park. The species, from data collected in
1979 at Gainesville, appeared to be rare. It was caught in only one
area and in one trap position out of 100. In 1980, however, it has
been taken in April and June at nine trap locations in both open
field and wooded areas.
The venom of this species has not been analyzed.
In two instances, workers of nickersoni were attracted to a
second (or third) larval instar of Diaprepes abbreviatus (L.), the
Sugar Cane Rootstalk Borer, in a Naves trap, and were able to kill and
dismember the weevil larva. This occurred on May 13 and June 9, 1980,
near Plymouth, Florida, in a wooded area probably relatively free from


97
Further tests were conducted in the Forest City grove and in a
control (non-grove) area to determine Diplorhoptrum populations, but
results have been erratic: of 50 tuna-baited Naves traps placed in the
Forest City grove on August 23, 1979, only three were positive for ants
and none with Diplorhoptrum. Fifty traps in a non-grove control area
in woods (subsequently discovered to be old abandoned grove land) were
negative.
Of 50 traps placed in the Forest City grove on Sept. 18, 1979,
two were positve for S_. (_D.) carol inensis. In a new control area, 10
traps were positive for S_. (D_.) carol inensis, two for S_. (ID.) pergandei
and six for S_. (D_.) xenovenenum.
Results of baiting with tuna indicated that at least three Diplor
hoptrum species were present in low numbers in the Apopka area.
To ascertain the role of Diplorhoptrum in Diaprepes larvae control,
50 Naves traps containing Diaprepes larvae were placed in the Forest
City grove on Oct. 26, 1979. No control traps were used. No Diplor
hoptrum were captured with the larvae. A second set of traps (n=88)
with larvae were put down on May 13, 1980 and left for 72 hours. Fifteen
traps were put down in a non-grove area as a control. In the grove,
Pheidole spp. killed five larvae in the traps, but there was no detect
able predatory activity by Diplorhoptrum. In the control area, S.. (D_.)
xenovenenum and S_. (JD.) nickersoni each attacked and killed a larva.
These results were repeated, with Diplorhoptrum spp. again killing two
of 15 larvae in the control area on June 9 1980.
In summary, even in a grove untreated with pesticides for 20 years,
Diplorhoptrum populations were low. In control or non-grove areas
within the quarantine area Dipiorhoptrum populations were higher, and


96
:S. (D^.) carolinensis workers. In three of these vials the fire ant
queen had been consumed except for large pieces of chi tin. In the fourth
vial, not even the chitinous pieces of the female were left. Of 100
fire ant queens put out in traps August 8, 1980, eight were found dead.
Of these, three died of unknown causes, three were found with S_. (]D.)
carol inensis workers, one with S^. (D.) xenovenenum workers and one with
Pheidole floridana workers. Diplorhoptrum were also found in the traps
of eight live queens. In five of those, the Diplorhoptrum workers had
been killed and chewed into pieces by the fire ant queen.
Further experiments with fire ant females as bait and the role of
the Diplorhoptrum species in the control of this pest species are
underway.
Predation on Diaprepes abbreviatus larvae
The Sugar Care Rootstalk Borer Weevil, Diaprepes abbreviatus (L.),
threatens citrus in Florida. The larvae feed on citrus roots and
develop undergroud for two to three years. The weevil is presently
confined to quarantine areas surrounding Apopka and Davie, Florida.
In light of the above predation studies, and the fact that the
Diaprepes larva spends such a long period of its life underground, it
seemed logical to suspect that underground predators could have a
strong impact on Diaprepes populations.
Preliminary to testing this hypothesis, on July 25, 1979, 100 tuna-
baited Naves traps were placed at the tree base, drip line and row middles
of four citrus groves in the quarantine area which ranged from fully
managed, heavily insecticided groves to a grove untreated pesticidally
for 20 years. No Diplorhoptrum were found except in the pesticidally
untreated Forest City grove.


103
PolymorphicHaving more than one form, said of ants with more than
one worker caste such as majors, minors or soldiers
PolygynousThe presence in one colony of two or more egg-laying
queens
ScapeThe rigid antennal section which arises from the head and
articulates with the funiculus
StratifiedNot random, selected on the basis of previously gathered
data
TumulusA mound of soil constructed at the entrance of an ant nest
and often characteristic of the species


ACKNOWLEDGEMENTS
I wish to thank my committee chairman, Dr. William F. Burn, for
his help and encouragement on all phases of this study, and Drs.
C.S. Lofgren, D.G. Griffin, S.H. Kerr and R.I. Sailer for their
assistance in preparing this dissertation.
I am grateful to Greg Erdos for instruction on SEM techniques,
to Dr. J.L. Nation for colony laboratory space and to P.T. Carlysle
for scanning electron micrographs of S^. (JD.) pi eta and S_. (I).) cor
tical is. I appreciate Dave Gowan's time for photographs of S_. (ID.)
pergandei tumuli.
Many thanks are also due to Dr. D.P. Wojcik for access to his
collections and literature files.
I am also grateful to Dr. J.C. Nickerson for his specimens of
SL (jD.) cortical is and his continuous encouragement and advice.


66


insecticides. (£.) nickersoni was not found in any citrus grove
area near Apopka or Orlando which had been treated by insecticides
herbicides.


41
Mississippi, it was nesting in soil and rotting stumps (Smith, 1931).
In Florida, Smith (1944) found it constructed small crater nests in
semiboggy ground near scrub and in loam beneath moss or pine needles.
Van Pelt (1958) found it in quite well-drained areas. Whitcomb et al.
(1972) found that it built flat honeycombed mounds about 1 foot deep in
canefields. He observed that the species seemed to be thriving and
was strictly nocturnal. The Whitcomb et al. observations seem
questionable for S^. (D.) pergandei and may be based upon a misdeter-
mination.


62


GLOSSARY
AlateHaving wings
Antennal clubThe last two segments at the tip of the antenna which,
in Solenopsis, are enlarged to form a club
BaseOf propodeum, the anterior dorsal surface of the propodeum
CrenelatedHaving towers, like a battlement
CryptobioticLife habits which involve remaining hidden, as under
ground, under debris or in other ways
DealatedWithout wings. In ants, females that have removed their
wings after the mating flight but before colony foundation
Dec!ivity'The inclined posterior surface of the propodeum
ExcisedCut out, posterior border of the head is concave
FuniculusSegmented part of the antenna extending from the end of
the scape to the tip of the antennal club
GasterThat portion of the abdomen, in Solenopsis, behind the post
petiole
InfuscationAn area darkened or tinged with brown or black
LestobioticA relationship in which a small ant species nests near a
larger ant species and robs the larger ants of their brood or
food supplies
Mayrian furrowsY-shaped mesonotal furrows in males of primitive ants
MyrmecophileAn animal that spends at least part of its life cycle
in an ant colony
Occipital borderThe posterior or hind margin of the head
PhragmosisThe head or posterior of the abdomen, often in the soldier
caste, is truncated to serve as a living plug for a nest entrance
Piligerous punctureA depression in the exoskeleton in which a hair
grows
102


58


Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
SOLENOPSIS (DIPLORHOPTRUM) (HYMENOPTERA:FORMICIDAE)
OF FLORIDA
By
Catherine R. Thompson
August, 1980
Chairman: Dr. William F. Burn
Major Department: Entomology and Nematology
Prior to this study, six species of the subgenus Solenopsis
(Diplorhoptrum) were reported from Florida. In the present study,
four new species were found in the state. New information on S^.
(Diplorhoptrum) prevalence, mating flights and role as predators was
obtained.
Review of the literature on Diplorhoptrum indicated that these
were thief-ants, present in relatively small numbers in the soil, and
usually in close association with nests of larger ants. Use of unique,
baited traps revealed Diplorhoptrum in unexpectedly large numbers with
a wide distribution in the soil. The ants were present in all but
extremely hydric habitats in Florida.
In this study, eight species of Diplorhoptrum were found: six
subterranean species, and two arboreal species. Four species previously
reported from Florida were not found. Examination of available voucher
specimens showed these to be misidentified. It seems possible that
authentic specimens of some of these species will eventually be found
x


24
Key to S. (Diplorhoptrum) Species of Florida
la) Mesopropodeal constriction strong (Fig. 21); promesonotum and
propodeum, in profile, strongly convex; petiolar node placed
somewhat anterior to the petiolar-postpetiolar juncture (Fig. 23)
so that the petiole has a distinct slender posterior portion;
color uniformly dark brown or black including the appendages; an
arboreal ant found nesting in twigs and small branches of
various trees pi eta Emery
b) Lacking above combination of characters; mesopropodeal constric
tion not as strong; promesonotum and propodeum never both strongly
convex; petiolar node placed near the petiolar-postpetiolar
juncture; color usually pale yellow, or if dark, then the ap
pendages are pale; subterranean (except for one rare yellow
arboreal species) 2
2a) Head, thorax, and gaster dark brown with pale brown or pale
yellow appendages; eyes of medium size for this group of species;
with 2, occasionally 3 facets; subterranean. . nickersoni n.sp.
b) Usually entirely pale yellow to somewhat darker yellow; one
species (carolinensis) with moderate infuscations of brown on
head and gaster 3
3a) Dense pilosity on head and usually on promesonotum arising from
large, obvious punctures; eyes small or weakly pigmented or
both 4
b) Pilosity not arising from large, obvious punctures and not
noticeably dense; eyes larger or at least pigmented, the facets
surrounded by a black matrix 7


PLATE 8
Figure 29. Lateral view of worker of S_. (£.) xenovenenum n. sp.
(83X)
Figure 30. Head of the worker of S^. (JD.) xenovenenum n. sp.
(150X)
Figure 31. Petiole and postpetiole of worker of S^. (D^.)
xenovenenum n. sp. (460X)
Figure 32. Dorsal view of worker of S_. (ID.) xenovenenum n. sp.
(84X)


113
Wheeler, W.M. 1901. The compound and mixed nests of American ants.
Amer. Natur. 35(Part II):513-539.
Wheeler, W.M. 1904a. Ants from Catalina Island, California. Bull.
Amer. Mus. Natur. Hist. 20:269-271.
Wheeler, W.M. 1904b. The ants of North Carolina. Bull. Amer. Mus.
Natur. Hist. 20:299-306.
Wheeler, W.M. 1905a. An annotated list of the ants of New Jersey.
Bull. Amer. Mus. Natur. Hist. 21:371-403.
Wheeler, W.M. 1905b. Ants from Catalina Island, Cal. Bull. Southern
California Acad. Sci. 4:60-63.
Wheeler, W.M. 1908. The ants of Texas, New Mexico and Arizona. Bull.
Amer. Mus. Natur. Hist. 24:399-485.
Wheeler, W.M. 1910. Ants: Their structure, development and behavior.
Columbia Univ. Press, New York. 663 p.
Wheeler, W.M.
477-505.
1913.
The ants of
Cuba. Bull. Mus.
Comp. Zool. 54
Wheeler, W.M.
1915.
Additions to
the ant-fauna of
North America.
Bull. Amer. Mus. Natur. Hist. 34:389-421.
Wheeler, W.M. 1916. Jjn H.L. Viereck (ed.), The Hymenoptera, or
wasplike insects of Connecticut. State Geol. Nat. Hist. Surv.
Bull. 22:1-824.
Wheeler, W.M. 1932. A list of the ants of Florida with descriptions
of new forms. J. New York Entomol. Soc. 40:1-17.
Whitcomb, W.H. and K. Bell. 1964. Predaceous insects, spiders and
mites of Arkansas cotton fields. Univ. Arkansas Agr. Exp. Sta.
Bull. 690:1-84.
Whitcomb, W.H., H.A. Denmark, A.P. Bhatkar, and G.L. Greene. 1972.
Preliminary studies of the ants of Florida soybean fields. Florida
Entomol. 55:129-142.
White, R.T. 1940. The relation of ants to the Japanese beetle and its
established parasites. J. New York Entomol. Soc. 48:85-99.
Wickham, H.F. 1892. Notes on some myrmecophi1ous Coleptera. Psyche
6:321-323.
Wickham, H.F. 1894. Further notes on Coleptera found with ants.
Psyche 7:79-81.
Wilson, E.O. 1964. The ants of the Florida Keys. Breviora 210:1-14.


7
walnut curculio larvae, Conotrachelus juglandis Lee., in young black
walnuts on the ground (Brooks, 1910). It attacked boll weevil larvae,
Anthomomis grandis Hubner (Hunter & Pierce, 1912; Hunter & Hinds, 1904;
Pierce, 1912) was observed carrying chinch bug eggs, Blissus leucopterus
(Say), (Headlee & McColloch, 1913) and eggs and small larvae of the
cabbage maggot Phorbia braassicae Bouch (Schoene, 1916). In studies
on the striped earwig, Labidura riparia (Pallas), spraying heptachlor to
control S^. (D.) molesta appeared to increase earwig populations. S. (£.)
molesta was subsequently observed feeding on earwig eggs in experimental
field plots (Gross & Spink, 1969).
S^. (£.) molesta seems to be particularly important as a predator
on codling moth, Carpocapsa pomonella Linn., larvae and pupae (Brooks
& Blakeslee, 1915; Jaynes & Marucci, 1947). The workers cut small
characteristic holes in the cocoons, accounting for 2.5 to 64.2% of all
attacked cocoons. Those near the colony site were killed by the ants in
2-5 minutes. S. (D.) molesta is listed as a predator in Arkansas cotton
fields (Whitcomb et al., 1972; Whitcomb & Bell, 1964). S^. (£.) molesta
has been found living with SL invicta and richteri Forel where it was
seen eating eggs and early larval instars of S. invicta (Collins &
Markin, 1971; O'Neal, 1974). Interestingly, S^. (D.) molesta was un
affected by the Mirex bait used to kill S. invicta in Louisiana (Markin
et al., 1974). Ayre (1963) fed S^. (£.) molesta colonies both live and
dead insects of a number of species. The ants consumed 39 of 49 live
insects and 53 of 54 dead insects. They also ate eggs of the weevil
Si tona scissifrons Say. Ayre concluded that S^. (j).) molesta "may be
as effective a predator as those species that capture larger insects,"
but "1imited in their choice of food because they are small" (p. 715).


8
The role of other Diplorhoptrum species as predators is not nearly
as clear. Published reports are few. S^. (D_.) texana was observed
attacking boll weevil larvae in Texas, Louisiana, and Mississippi
(Hunter & Pierce, 1912). S_. (D_.) molesta validiuscula Emery was often
found attacking codling moth larvae under experimental tree bands in
West Virginia apple orchards (Jenne, 1909).
Biology and Ecology
Because Diplorhoptrum species are still in considerable taxonomic
flux, there are few published reports relating to the biology and ecology
of the species. The bulk of information concerns microhabitat and eco
system distributions. In Table 1 (Appendix), data on nesting locations
of S.. (D.) molesta is presented. Although this species seems able to
establish colonies in most types of habitats, on the microhabitat level
it displays a distinct preference for cover, particularly stones.
What is known concerning the biology of Diplorhoptrum species
consists of observations dispersed through the general literature on
ants with almost no exhaustive studies. For example, in at least one
western state (Utah) S^. (D_.) molesta validiuscula is considered a
dominant Diplorhoptrum species, is 1.3 mm long, lives under stones,
bark, and logs (Cole, 1942), and has been observed feeding on chicks,
rats, and mice (Eckert & Mall is, 1 937). Hayes (1 920) has conducted the
only biological study of S^. (JD.) molesta. His thorough study determined
life tables for the brood, field colony size, queen egg production,
flight information, and methods of laboratory colony maintenance.
One of the most interesting habits of S. (D.) molesta, as well as
other Diplorhoptrum species, is lestobiosis. This ant has been found


SOLENOPSIS (DIPLORHOPTRUM) (HYMENOPTERA:FORMICIDAE) OF FLORIDA
By
Catherine R. Thompson
A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1980

Copyright 1980
by
Catherine Rose Thompson

ACKNOWLEDGEMENTS
I wish to thank my committee chairman, Dr. William F. Burn, for
his help and encouragement on all phases of this study, and Drs.
C.S. Lofgren, D.G. Griffin, S.H. Kerr and R.I. Sailer for their
assistance in preparing this dissertation.
I am grateful to Greg Erdos for instruction on SEM techniques,
to Dr. J.L. Nation for colony laboratory space and to P.T. Carlysle
for scanning electron micrographs of S^. (JD.) pi eta and S_. (I).) cor
tical is. I appreciate Dave Gowan's time for photographs of S_. (ID.)
pergandei tumuli.
Many thanks are also due to Dr. D.P. Wojcik for access to his
collections and literature files.
I am also grateful to Dr. J.C. Nickerson for his specimens of
SL (jD.) cortical is and his continuous encouragement and advice.

TABLE OF CONTENTS
PAGE
ACKNOWLEDGMENTS 111
LIST OF FIGURES vii
ABSTRACT x
INTRODUCTION 1
REVIEW OF LITERATURE 3
Taxonomy 3
Distribution 4
Economic Importance 5
Biology and Ecology 8
Venom Chemistry 11
MATERIALS AND METHODS 12
Taxonomy 12
Lactophenol Fixation 13
Scanning Electron Micrography 14
Field Studies 15
Collecting Techniques 15
Naves Traps 16
Local Distribution Study 17
Use of Light Trap Collections 18
Laboratory Studies 18
Colony Nest Materials 18
Feeding 20
Queen Colony Founding 20
RESULTS 22
Section I: A Taxonomic Review of the S..
(Diplorhoptrum) of Florida 22
Introduction 22
Key to S. (Diplorhoptrum) Species of Florida 24
1. Solenopsis (Diplorhoptrum) abdita n.sp.. . 27
Diagnosis 27
Description 27
Worker 27
Female 28
Male 29
iv

PAGE
Types 29
Discussion 29
2. Solenopsis (Diplorhoptrum) carolinensis
Forel. 31
Diagnosis 31
Discussion 31
3. Solenopsis (Diplorhoptrum) cortical is Forel. 33
Diagnosis 33
Discussion 33
4. Solenopsis (Diplorhoptrum) mol esta (Say) ... 34
Diagnosis 34
Discussion 34
5. Solenopsis (Diplorhoptrum) nickersoni n. sp. 36
Diagnosis 36
Description 36
Worker 36
Female 37
Male 37
Types 37
Discussion 38
6. Solenopsis (Diplorhoptrum) pergandei Forel . 40
Diagnosis 40
Discussion 40
7. Solenopsis (Diplorhoptrum) pieta Emery .... 42
Diagnosis 42
Discussion 42
8. Solenopsis (Diplorhoptrum) reinerti n.sp.. . 43
Diagnosis 43
Description 43
Worker 43
Female 44
Male 45
Types 45
Discussion 45
9. Solenopsis (Diplorhoptrum) tennesseensis
M. R. Smith 46
Diagnosis 46
Discussion 46
10. Solenopsis (Diplorhoptrum) texana Emery. ... 47
Diagnosis 47
Discussion. . 47
11. Solenopsis (Diplorhoptrum) truncorum Forel . 48
Diagnosis 48
Discussion 48
12. Solenopsis (Diplorhoptrum) xenovenenum n.sp. 49
Diagnosis 49
Description 49
Worker 49
Female 50
Male 51
Types 52
Discussion 52
v

PAGE
Section II. Subterranean Distribution of
Diplorhoptrum Species 71
Section III. The Mating Flights of S_. (jl.) pergandei ... 88
Tumuli Construction 88
Flight Factors 89
Flight and Postflight Activities 90
Section IV. The Role of S_. (Piplorhoptrum) as Underground
Predators 95
Preliminary Experiments 95
Predation on Fire Ant females 95
Predation on Diaprepes abbreviatus Larvae 96
SUMMARY 99
GLOSSARY 102
APPENDIX 104
LITERATURE CITED 105
BIOGRAPHICAL SKETCH 115
vi

LIST OF FIGURES
FIGURE PAGE
1 Lateral view of worker of S.. (J).) abdita n.sp. (65X). . 54
2 Head of the worker of S^. (JD.) abdita n.sp. (120X) .... 54
3 Petiole and postpetiole of worker of S. (D.) abdita
n.sp. (340X) 54
4 Dorsal view of worker of S.. (D.) abdita n.sp. (50X) ... 54
5 Lateral view of worker of S. (D.) carolinensis Forel
(60X) 56
6 Head of worker of S^. (£.) carol inensis Forel (130X) ... 56
7 Petiole and postpetiole of worker of S. (D.) carolinensis
Forel (290X) 56
8 Dorsal view of worker of S. (D.) carolinensis Forel
(56X) 56
9 Lateral view of worker of S^. (Dj cortical is Forel (90X). 58
10 Head of the worker of S^. (jD.) cortical is Forel (200X) . 58
11 Petiole and postpetiole of worker of S. (D.) cortical is
Forel (360X) 58
12 Dorsal view of worker of S. (DO cortical is Forel (65X) 58
13 Lateral view of worker of ,S. (£.) nickersoni n.sp. (75X). 60
14 Head of the worker of S. (j).) nickersoni n.sp. (120X) . 60
15 Petiole and postpetiole of worker of S. (D.) nickersoni
n. sp. (420X) 60
16 Dorsal view of worker of S_. (£.) nickersoni n.sp. (65X) 60
17 Lateral view of worker of S^. (£.) pergandei Forel (79X) 62
18 Head of the worker of S^. (CL) pergandei Forel (98X) ... 62
vi i

FIGURE
PAGE
19 Petiole and postpetiole of worker of (JD.) perqandei
Forel (165X) 62
20 Dorsal view of worker of (JD.) pergandei Forel (75X). 62
21 Lateral view of worker of Su (D.) picta Emery (70X) ... 64
22 Head of the worker of S^. (JD.) picta Emery (140X) .... 64
23 Petiole and postpetiole of worker of (13.) picta
Emery (378X) 64
24 Dorsal view of worker of S. (JD.) picta Emery (70X) ... 64
25 Lateral view of worker of S^. (JD.) reinerti n.sp. (90X). 66
26 Head of the worker of S-. (JD.) reinerti n.sp. (140X) ... 66
27 Petiole and postpetiole of worker of S^. (ID.) reinerti
n.sp. (460X) 66
28 Dorsal view of worker of S^. (D.) reinerti n.sp. (50X) . 66
29 Lateral view of worker of S. (D.) xenovenenum n.sp.
(83X) 68
30 Head of the worker of S.. (ID.) xenovenenum n.sp. (150X). 68
31 Petiole and postpetiole of worker of S^. (JD.)
xenovenenum n.sp. (460X) 68
32 Dorsal view of worker of S_. (JD.) xenovenenum n.sp. (84X). 68
33 Cluster of mating flight tumuli of S^. (JD.) pergandei
Forel 70
34 Mating flight tumulus of S^. (JD.) pergandei Forel 70
35 Mating flight tumulus of S^. (D.) pergandei Forel 70
36 Example of Naves trap samples of Diplorhoptrum and other
species distribution in a long leaf pine-turkey oak woods
on June 24, 1979, at Gainesville, Florida 72
37 Diplorhoptrum species captured by Naves trap in an open
field at Gainesville, Florida, from June 1979-June 1980 73
38 Diplorhoptrum species captured by Naves trap in a long
leaf pine-turkey oak woods at Gainesville, Florida,
from June 1979-June 1980 74
viii

FIGURE PAGE
39 Five month (June-Oct., 1979) summation of the
distribution by trapping of (j).) carol inensis
in an open field at Gainesville, Florida 79
40 Five month (June-Oct., 1979) summation of the
distribution by trapping of jS. (j).) abdita in an open
field at Gainesville, Florida 80
41 Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (]D.) carol inensis in
a long leaf pine-turkey oak woods at Gainesville,
Florida 81
42 Five month (June-Oct., 1979) summation of the
distribution by trapping of S^. (|).) abdita in a long
leaf pine-turkey oak woods at Gainesville, Florida. ... 82
43 Five month (June-Oct., 1979) summation of the
distribution by trapping of S^. (j).) xenovenenum
in a long leaf pine-turkey oak woods at Gainesville,
Florida 83
44 Number of months each trap site in an open field at
Gainesville, Florida, was positive for three species of
Diplorhoptrum (June 1979-June 1980) 84
45Number of months each trap site in a long leaf pine-turkey
oak woods at Gainesville, Florida, was positive for
three species of Diplorhoptrum (June 1979-June 1980). . 85
46Correlation of S^. (D.) pergandei mating flights with
times of sunrise in Gainesville, Florida 91
ix

Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
SOLENOPSIS (DIPLORHOPTRUM) (HYMENOPTERA:FORMICIDAE)
OF FLORIDA
By
Catherine R. Thompson
August, 1980
Chairman: Dr. William F. Burn
Major Department: Entomology and Nematology
Prior to this study, six species of the subgenus Solenopsis
(Diplorhoptrum) were reported from Florida. In the present study,
four new species were found in the state. New information on S^.
(Diplorhoptrum) prevalence, mating flights and role as predators was
obtained.
Review of the literature on Diplorhoptrum indicated that these
were thief-ants, present in relatively small numbers in the soil, and
usually in close association with nests of larger ants. Use of unique,
baited traps revealed Diplorhoptrum in unexpectedly large numbers with
a wide distribution in the soil. The ants were present in all but
extremely hydric habitats in Florida.
In this study, eight species of Diplorhoptrum were found: six
subterranean species, and two arboreal species. Four species previously
reported from Florida were not found. Examination of available voucher
specimens showed these to be misidentified. It seems possible that
authentic specimens of some of these species will eventually be found
x

in Florida. Independent studies have shown that the venom of one of the
new species contains (5Z,8E)-3-heptyl-5-methyl pyrrolizidine, the first
recorded occurrence of this substance in any animal or plant.
In subterranean studies, 50 traps each in an open field and a long
leaf pine-turkey oak woods were baited each month for a year. Five
Diplorhoptrum species came to the traps, three of which were new. The
dominant species in both habitats was SL (D.) carolinensis, while S. (Dj
pergandei was found only in the woods site, and the remaining species
were present in both habitats. The nest locations and foraging terri
tories were mapped and found to have mosaic patterns. Ant activity
nearly stopped between October and November and did not reach high levels
again until the following May. Soil temperature is probably a major fac
tor in this activity pattern. May soil temperatures were five to seven
degrees higher than those in April.
The only Diplorhoptrum species which constructed nest structures at
the soil surface was S^. (D.) pergandei. These structures were crenelated
tumuli constructed for mating flights. The tumuli apparently allow more
sexuals to remain near the soil surface and also provide a surface for
flight takeoff. Mating flights for this species took place one half hour
before dawn from June through August, mostly when there had been rain
in the previous 24 hours.
The predatory activities of Diplorhoptrum were studied. They
readily killed and consumed newly mated imported fire ant queens,
Solenopsis invicta Burn. Several Piplorhoptrum species were also found
to kill and eat the larvae of the Sugar Cane Rootstalk Borer, Diaprepes
abbreviatus (L.). The indications are that Diplorhoptrum species may be
important subterranean predators and should be further investigated for
their potential as biological control agents.
xi

INTRODUCTION
There are approximately 8,000 known taxa of ants in the world, and
the habits exhibited are extremely diverse (Wilson, 1971). Three
principal ecological types may be said to exist in the Formicidae.
These are: I. Arboreal species, ants which nest in trees and forage
for food or obtain their food in trees or non-aborescent plants, II.
Terrestrial ants which nest in the soil and forage for food mostly on
the soil surface, and III. Subterranean or cryptobiotic ants, ants
that nest and forage underground or beneath debris seldom coming to the
soil surface. Species may, of course, occupy more than one of these
habitats.
Cryptobiotic ants are interesting academically because they often
are highly modified structurally Ants of the generally cryptobiotic
tribes Dacetini and Basicerotini, as well as other aberrant genera,
have been described and figured in many papers, of which Brown (1962),
Brown and Kempf (1967), Brown (1974) and Brown (1977) are examples.
The highly modified structures of these ants probably adapt them for
specialized predation on soil arthropods and are fortuitously useful
in taxonomic studies.
Subterranean ants are generally thought to be lestobiotic.
Solenopsis (Diplorhoptrum) as well as related subterranean genera
such as 01igomyrmex, Carebara, Carebarella are also more generalized
in structure. They have few specialized features which makes them
1

2
difficult to study taxonmica11y. Whitcomb et al. (1972) and Burn
et al. (1977) suggested that this group of genera and species might be
much more important as generalized subterranean predators than had
been previously suspected, and that their role in lestobiosis might
be secondary.
These studies were undertaken as an investigation into the
abundance, ecology, taxonomy, and predatory importance of these ants
in Florida. The data will revise thinking on the importance of these
predators in the subterranean ecosystem. The study also helps to
emphasize the need for similar studies on a world-wide basis.

REVIEW OF LITERATURE
Taxonomy
The genus Solenopsis is essentially cosmopolitan and is found in
all but the coldest parts of the world. The genus was divided by
Creighton (1950) into three subgenera: Solenopsis, Euopthalma and
Diplorhoptrum. The painful stings inflicted by members of the
Solenopsis (Solenopsis) group have attracted public attention as the
red Imported Fire Ant Solenopsis invicta Burn continues to spread in
the southern and southwestern U.S.
While not endearing themselves to the general public, the genus
Solenopsis is also no favorite of ant taxonomists. Creighton (1950)
grumbled "The student of North American ants may count himself fortunate
that so few species of this difficult genus occur in our latitudes"
(p.226). The worker caste in Solenopsis has undergone extreme con
vergence, making identification to species difficult. Unfortunately
most of this convergence has occurred in Diplorhoptrum.
The taxonomic postion of Diplorhoptrum is subject to discussion.
Ettershank, in his revision of the Solenopsini (1966), synonymized
Diplorhoptrum under Solenopsis. Baroni-Urbani (1968) resurrected the
group and gave it full generic status. Unfortunately he based his
determination on the male genitalia of the common European species,
S_. (.D.) fugax (Latreille), without knowledge of the Neartic and Neo
tropical fauna. Although Creighton suspected that male and female
3

4
morphology may indeed be the only reliable source of characters on
which to base Diplorhoptrum taxonomy, the fact remains that at present
few of the males are known. For this reason American myrmecologists
have been reluctant to accept Baroni-Urbani's work (pers. comm., W. F.
Burn). Retaining Diplorhoptrum as a subgenus may be acceptable simply
for convenience: as a group Diplorhoptrum are usually small, mono-
morphic species as opposed to the larger, polymorphic, free-living fire
ants (MacConnell et al., 1976). All S^. (Diplorhoptrum) species have the
2nd and 3rd joints of the funiculus distinctly broader than long, whereas
in S.. (Solenopsis) and (Euopthalma) species these joints are longer than
broad.
To search the literature on Piplorhoptrum, one must be aware that
the species most frequently published upon, S^. (jL) molesta, is also
found under five synonyms: Myrmica molesta Say, Myrmica minuta Say,
Myrmica exigua Buckley, Solenopsis debilis Mayr, and Solenopsis
molesta (Say).
There has been an unfortunate tendency to identify every small
yellow thief ant as S^. (JD.) molesta. The problem is compounded by the
fact that S^. (JL) mol esta is the only economic pest in the Diplorhoptrum
group. As a result much of the literature concerning S^. (]}.) molesta
may be based on misdeterminations.
Distribution
Creicjton (1950) listed 12 taxa of Pi pi orhoptrum for North America.
The most recent compilation (Smith, 1979) also contains 12 taxa: 10 from
Creighton's original list, one species renamed, and one placed
in synonomy. At least one Diplorhoptrum species has been reported

5
from each of the contiguous 48 states with S_. (_D.) molesta (Say), the
most widespread species, reported from 30 states. The species reported
from Florida are S_. (J3.) molesta (Say), S_. (j).) pergandei Forel,
S_. (D.) pi eta Emery, S_. (_D.) tennesseensis Smith, S_. (£.) texana Emery,
and S_. (jD.) truncorum Forel.
Economic Importance
Although not as notorious as their fire ant relatives, Diplorhoptrum,
or thief ants as they are commonly called, contains one species,
Solenopsis (Diplorhoptrum) molesta (Say), which is a pest in fields and
dwellings. As a result of this pest status, and erroneous identifi
cations, most of the literature deals with this species. Although
Creighton (1950) reported it to be distributed only in the central and
eastern states, it has subsequently been reported from eight of the 11
western states (Appendix).
S_. (£.) molesta is best known as a economic pest of sorghum.
The ant is known as the "kafir ant" in Kansas (Bryson, 1941; Hayes,
1925) where it has been called the single most damaging pest of planted
sorghum (Burkhardt, 1959). The ants diminish sorghum stands by feeding
on germinating sorghum seed (Young and Howell, 1964). They have
destroyed thousands of acres of sorghum necessitating one to six
replantings and then not always with a resultant full stand (McColloch
and Hayes, 1916). Srivastava and Bryson (1956) found that tilling the
soil, planting early, and using various insecticides or insecticide-
fungicides prior to planting helped avoid damage. All of the com
pounds tested were effective, while the ants damaged 50% of the check
seeds. McColloch and Hayes (1916) found that only late plantings were

6
damaged. Early planting, along with seed treatment, fall plowing, and
surface planting have essentially eliminated the kafir ant problem.
Su (D.) molesta has been reported to eat out the interiors of corn
kernels, and in New York is known as the "little yellow ant" (Fitch,
1856) and the "yellow field ant" (Felt, 1916). There are reports of
strawberries (Fitch, 1920) and blackberries (Webster, 1893) damaged by
S^. (D_.) molesta. This ant may also indirectly damage crops through its
habit of tending various species of aphids (Landis, 1967; Smith &
Morrison, 1916; Webster, 1893). It attacked the cocoons of the Japanese
beetle parasite Tiphia and killed 20% in the laboratory (White, 1940).
Smith (1965) reported S_. (D.) molesta as a host of a poultry tapeworm.
S. (D.) molesta is one of only two of our native ant species which
invades homes (Wheeler, 1910). Herrick (1921) reported on the "little
fiery ant" which invaded kitchens. While Forbes (1896, 1920) and
Fitch (1856) stated that this ant had a sweet tooth, Back (1937) said
that it fed "almost entirely" on greasy substances. It is possible that
a number of Diplorhoptrum species may be involved. _S. (D.) molesta
validiuscula Emery is a common pest in California homes where it lives
in crevices around sinks and feeds on greases, meats, and cheese
(Mal lis, 1941). Among the more curious of S_. (D^.) molesta dietary
preferences was an insect collection (Fitch, 1856) while an
artist complained that _S. (£.) molesta was eating his paints (Webster,
1893).
Nearly as many reports in the literature point to S_. (CL) molesta
as a valuable predator as malign this species as an economic pest.
Brooks (1906) observed S^. (£.) mol esta in large numbers feeding on
grape curculio, Craponius inaegualis (Say), larvae. The ant killed

7
walnut curculio larvae, Conotrachelus juglandis Lee., in young black
walnuts on the ground (Brooks, 1910). It attacked boll weevil larvae,
Anthomomis grandis Hubner (Hunter & Pierce, 1912; Hunter & Hinds, 1904;
Pierce, 1912) was observed carrying chinch bug eggs, Blissus leucopterus
(Say), (Headlee & McColloch, 1913) and eggs and small larvae of the
cabbage maggot Phorbia braassicae Bouch (Schoene, 1916). In studies
on the striped earwig, Labidura riparia (Pallas), spraying heptachlor to
control S^. (D.) molesta appeared to increase earwig populations. S. (£.)
molesta was subsequently observed feeding on earwig eggs in experimental
field plots (Gross & Spink, 1969).
S^. (£.) molesta seems to be particularly important as a predator
on codling moth, Carpocapsa pomonella Linn., larvae and pupae (Brooks
& Blakeslee, 1915; Jaynes & Marucci, 1947). The workers cut small
characteristic holes in the cocoons, accounting for 2.5 to 64.2% of all
attacked cocoons. Those near the colony site were killed by the ants in
2-5 minutes. S. (D.) molesta is listed as a predator in Arkansas cotton
fields (Whitcomb et al., 1972; Whitcomb & Bell, 1964). S^. (£.) molesta
has been found living with SL invicta and richteri Forel where it was
seen eating eggs and early larval instars of S. invicta (Collins &
Markin, 1971; O'Neal, 1974). Interestingly, S^. (D.) molesta was un
affected by the Mirex bait used to kill S. invicta in Louisiana (Markin
et al., 1974). Ayre (1963) fed S^. (£.) molesta colonies both live and
dead insects of a number of species. The ants consumed 39 of 49 live
insects and 53 of 54 dead insects. They also ate eggs of the weevil
Si tona scissifrons Say. Ayre concluded that S^. (j).) molesta "may be
as effective a predator as those species that capture larger insects,"
but "1imited in their choice of food because they are small" (p. 715).

8
The role of other Diplorhoptrum species as predators is not nearly
as clear. Published reports are few. S^. (D_.) texana was observed
attacking boll weevil larvae in Texas, Louisiana, and Mississippi
(Hunter & Pierce, 1912). S_. (D_.) molesta validiuscula Emery was often
found attacking codling moth larvae under experimental tree bands in
West Virginia apple orchards (Jenne, 1909).
Biology and Ecology
Because Diplorhoptrum species are still in considerable taxonomic
flux, there are few published reports relating to the biology and ecology
of the species. The bulk of information concerns microhabitat and eco
system distributions. In Table 1 (Appendix), data on nesting locations
of S.. (D.) molesta is presented. Although this species seems able to
establish colonies in most types of habitats, on the microhabitat level
it displays a distinct preference for cover, particularly stones.
What is known concerning the biology of Diplorhoptrum species
consists of observations dispersed through the general literature on
ants with almost no exhaustive studies. For example, in at least one
western state (Utah) S^. (D_.) molesta validiuscula is considered a
dominant Diplorhoptrum species, is 1.3 mm long, lives under stones,
bark, and logs (Cole, 1942), and has been observed feeding on chicks,
rats, and mice (Eckert & Mall is, 1 937). Hayes (1 920) has conducted the
only biological study of S^. (JD.) molesta. His thorough study determined
life tables for the brood, field colony size, queen egg production,
flight information, and methods of laboratory colony maintenance.
One of the most interesting habits of S. (D.) molesta, as well as
other Diplorhoptrum species, is lestobiosis. This ant has been found

9
living beside or with 33 different species of ants of four subfamilies
(Cook, 1953; Hayes, 1920; King, 1896, 1901a & b; Mall is, 1941; Mann,
1911a; and Wheeler, 1901). S_. ([).) molesta will also live amicably with
the termite Reticuli termes flavipes (Kollar) in the laboratory (Smythe &
Coppel, 1973). The data on Diplorhoptrum species which are freeliving
or lestobiotic are lacking, spotty, or contradictory. While Kennedy
(1938) found four nests of S_. (JD.) texana, all lestobiotic, Wheeler and
Wheeler (1963) made 81 collections of which 53 were independent nests.
They were unable to determine if the ants were S.. (jl.) molesta or
S.. (£.) molesta val idiuscula. They found that the independent nests
had V1 dia. chambers as much as 5" below the soil surface, but mostly
in the upper 2V. As Wheeler (1901) pointed out, however, there could
be long connecting galleries between these species and their suspected
host galleries or no relationship at all.
Diplorhoptrum are themselves hosts of a number of guests. Wheeler
discovered the first guest, reported only as a Hymenopteran (Brues,
1903). Fall (1920) found a new species of blind beetle Alaudes alternata
Fall in S^. ([).) molesta nests. King (1895, 1897) observed a mite on
larvae which attached midway between the thorax and abdomen and a
Staphylinid of the tribe Aleocharini. Schwarz (1890a & b, 1896) found
Coleptera of the genera Lithocharis and Myrmecochara with S_. (D.)
mol esta, but believed the former to be an accidental guest. Wickham
found the latter beetle with the ants, first calling it Gyrophaena sp.
but later correcting the name (1892, 1894) to Myrmecochara crinita
Casey. He felt this species to be a true myrmecophile along with
Atheta exilissima Casey. Wing (1951) found a number of wasp guests of
the genera Buresopria and Auxopaedeutes, and Loxotropa cal ifornica
Ashmead.

10
S. (D.) molesta appears to have few natural enemies, although
research lags in this area. Beal (1911, 1912) found that a flicker,
Colaptes auratus L. subsp., and the kingbird or bee martin, Tyrannus
tyrannus (L.) feed on S.. ([).) molesta. No less than 39 species of birds
were observed feeding on a mating flight of S.. ([).) molesta (Judd,
1901). Diplorhoptrum probably have a number of ant enemies, but only
two are reported: Hung (1974) found that 10% (or 80) of the ants'
heads in the garbage pile of a Conomyrma nest were those of S_. (2-)
molesta. Burn et al. (1977) suggest false phragmosis evolved by
Pheidole lamia Wheeler serves as a defensive tactic against subterranean
ants, mainly Diplorhoptrum.
It is fortunate that two astute observers have published their
observations on the mating flights of S.. (I).) molesta. In Kansas,
Hayes (1925) observed a flight at 5 p.m. on July 27, 1920, which con
tinued until dusk, and a flight July 5, 1921. Both were preceded by
heavy rain. He noted that mating occurred in the air, that females
outnumbered males (unusual in ants), and that males mated more than
once. Farther north in Canada, late August flights occurred
(Macnamara, 1945; Wheeler, 1916) and Macnamara observed a dense evening
swarm, 3-4 ft in diam. and at its lowest point about 3 ft off the
ground. He saw that the swarm was sluggish and noticed, most impor
tantly, that the females were carrying workers on their bodies. Wing
(1951) reported that W. L. Brown found approximately 20% of the S.. (£.)
mol esta females in a Philadelphia flight had one or rarely two workers
attached to their legs.

11
Venom Chemistry
Venom chemistry and behavior associated with it have attracted
increasing interest and research in the past decade. Jones et al. (1979)
identified a new venomous constituent in the poison gland of S_. (D_.)
molesta and (D.) texana. The chemical, 2-hexyl-5-pentyl-pyrrolidine,
is the first known 2,5-dialkyl pyrrolidine from a natural source.
More recently, a new alkaloid, (5Z,8E)-3-heptyl-5-methyl pyrrolizidine
has been identified (Jones et al., in press) in S^. (D.) xenovenenum
n.sp. denoted as a species near (j).) tennesseensis. Wilson (1975)
studied Pheidole dentata Mayr and found a chemical alarm-recruitment
system in the minor caste which recruits the majors. It is a chemical
which specifically recruits the majors to ants of the genus Solenopsis.
Holldobler (1973) reported that S_. (D.) fugax (Latreille) (European
species) has a recruitment pheromone produced by the Dufour gland and a
repellent substance produced by the poison gland. The repellent pre
vents brood-keeping ants from defending their own larvae against the
Diplorhoptrum. Blum and Jones (1980) found that the S^. (D_.) fugax
substance repelled 18 species of ants. The secretion of one gland
would stop Lasius flavus McCook from using a nest entrance for almost
an hour. The main component was trans-2-butyl-5-heptylpyrrolidine, a
dialkyl-pyrrolidine which is evidently an integral part of S.. (D.)
fugax raiding strategy.

MATERIALS AND METHODS
Taxonomy
Because the largest Florida S. (Diplorhoptrum) worker is only
1.8 mm long, it is imperative that anyone wishing to study this group
have at their disposal a microscope with a minimum of 40 diameters of
magnification. The Wild microscope used for this study was also
equipped with an ocular micrometer.
Traditional measurement techniques were utilized and specimens
were compared with types at the U.S. Natural History Museum in
Washington, D.C., and the Museum of Comparative Zoology at Harvard
University, Cambridge, Mass. Measurements of specimens and indexes
calculated were as follows:
1. Head width: greatest width of the head in full face view.
2. Head length: greatest length of the head in full face
view, but excluding the mandibles.
Head width x 100
3. Head index:
4
Head length
Head depth: measured on line running through the eye and
perpendicular to line running from just above mandibular
insertion to point where neck meets thorax.
5. Thoracic length: greatest length of thorax in lateral view.
6. Scape length: middle of antennal socket to tip of scape.
7. Scape index: ^ f?th 100 .
K Head length
8. Funiculus length: tip of scape to tip of funicular club.
12

13
9. Club length: length of last 2 antennal segments which
form the typical club.
10. Body length: total length of specimen from mandibles to
tip of the gaster. This measurement cannot be made as
accurately as the others. Specimens were so rarely in a
natural position on the pins that only a rough estimate
was made of total body lengths.
Eye length: greatest length of the eye.
11
12
Eye index- ^e_length x 100
tye inaex. Head length
Specimens studied were obtained from as many locations as possible
in Florida. Series collected by 0. P. Wojcik (USDA, Gainesville,
Florida) and by A. F. Van Pelt (collections in the Florida State
Collection of Arthropods, Gainesville, Florida) and Dr. William F.
Burn (Dept, of Entomology and Nematology, Univ. of Florida, Gainesville,
Florida) were studied.
Lactophenol Fixation
A novel method for taxonomic study of ants was use of slide-
mounted specimens prepared by a four minute lactophenol fixation pro
cess (Esser, 1973) initially developed for nematode studies. This
rapid procedure cleared specimens and allowed particularly detailed
study of pubescence.
1. The ants were removed from alcohol and placed in water in a
watch glass set inside a petri dish on a hot plate.
2. The specimens were heated to 370C and lactophenol added
until the watch glass was full.

14
3. The specimens were heated an additional two minutes
then were cooled 10 minutes.
4. A ring of "zut" (Thorn, 1935), a sealant used to mount
helminths, is placed on a slide. The ring is built up
enough to avoid crushing the specimens (and requires practice
and extra specimens). The ants, in some lactophenol
solution, are placed in the ring and a cover slip placed
over the ants and the zut.
Having a number of ants per slide ensured that at least one would be
positioned correctly for any structure studied.
Scanning Electron Micrography
Diplorhoptrum workers are so small that use of the usual black
carbon contact cement was nearly impossible. Split-second timing was
needed, otherwise the cement dried or the specimen disappeared under
the cement.
These problems were overcome by the use of double-stick white
labels. The ants were arranged on the label and pushed into the ad
hesive. But a problem developed with charging (a process which results
in bright light bouncing off the specimen and obscuring structure),
even though the specimens had been double-gold-coated at three minutes
per coat with a break between coatings to dissipate heat.
To alleviate charging, the ants were placed on the sticky labels
and spots of carbon glue were placed near the specimens and smeared
into contact with the tarsi or under parts of the body. In this way
conduction was increased and charging reduced.

15
Field Studies
Collecting Techniques
Unlike many terrestrial ant species, Diplorhoptrum have few
surface indications of nest location, with the exception of S_. (JD.)
pergandei mating flight tumuli (Figure 29). Diplorhoptrum are
nocturnal and, even at night, forage little above ground except in
moist areas. As a result, conventional methods were not as effective
in locating and collecting these ants; however, the following
techniques were utilized with some success:
1. Lifting bark from bases of trees and from rotten logs.
Species most frequently obtained were S^ (th) pergandei and S^ (I).)
carolinensis.
2. Searching for unnatural soil disturbances such as slight
mounds and color changes indicating excavations, or for parts of dead
insects grouped in one place.
3. Overturning stones, logs, and other soil cover and tearing
apart rotten logs.
4. Searching shovelfuls of soil for foragers, particularly in
moist areas and along the edges of tree roots. Although this method
would seem time consuming and the finding of any ants a matter of
chance, it was one of the most effective. One morning's work and
nearly 200 shovelfuls produced one S^. (jD.) carol inensis queen and
workers and an additional sample of workers; a second morning's work
produced one S^. (JD.) pergandei queen and colony. In a third area one
half hour of work produced two S_. (ID.) carol inensis queens and colones.

16
These collections were in different habitats, the first two areas
were xeric while the third area was hydric.
Naves Traps
Naves traps (unpublished technique) were baited with honey agar
(Bhatkar and Whitcomb, 197C), cabbage loopers, Diaprepes beetle larvae,
Fire Ant queens (£. invicta), or most often tunafish. The Naves trap
is made by modifying a two ml sidetabbed Dispobeaker (Scientific
Products) as follows: A teasing needle is heated and used to melt
0.5-0.9 mm diam. holes in the cap and bottom of the beaker. Three
holes are placed in the cap top, six around the sides of the cap and
three in the bottom of the trap body. All attempts to further
standardize hole size by wiring a soldering iron with 1/16 inch
copper wire failed; the wire would not hold enough heat to melt the
plastic. Acrylic red yarn tied around the trap under the side tabs
served as a marker and means of pulling the trap from the ground.
A narrow bladed trowel (5 cm at greatest width) was used to
bury the traps with their bases at a depth of 14 cm. It was found that
less than 10 cm depths resulted in traps filled with fine sand which
sifted through the trap tops in dry soils. Depths of 18 cm or more
made trap recovery and replacement of the soil difficult. The 14 cm
depth was chosen as an average and employed throughout trapping ex
periments as an experimental constant.
As a note of caution, even the small holes of these traps did not
exclude a number of other ant species: Pheidole metal!escens Emery,
Brachymyrmex depilis Emery, Pheidole dentata Mayr, and P. floridana
Emery. Other less frequent species were Ponera pennsylvanica Buckley

17
and a Strumigenys species. In areas infested with S_. invicta, the
fire ants chewed at the cap holes until they were large enough to gain
entrance to the bait. Their chewing habit cost me considerable time
in the making of new caps.
Unfortunately, the Dispobeakers have been discontinued by the
manufacturer. Traps have now been made from plastic, cap-attached
vials made by Bio-Rad Company. These traps will be utilized in South
America studies in the near future but are still in the experimental
stage.
Local Distribution Study
Studies of small area distribution of Diplorhoptrum species were
undertaken utilizing stratified sampling. A 5 x 10 square meter grid
was laid out in a open field at the Gainesville Airport. The field is
mowed twice a year, maintaining grasses and occasional young turkey
oaks (Quercus laevis Walt.) below 3-4 ft. The area is designated for
use only as an emergency runway. A second 5x10 square meter grid was
laid out in a long leaf pine (Pinus palustris Mi 11.)--turkey oak woods
bordering the northeast side of the open field.
Biweekly (June 1979-July 1979) and then bimonthly (Aug. 1979-
June 1980) Naves traps were loaded with tunafish and placed one in
the center of each square meter of the grids. The traps were placed
at a depth of 14 cm for 24 hours. At the end of 24 hours the traps were
taken up. Traps with ants were quickly placed in snap-top vials for
later indentification. The square meter was rebaited with another trap.
Following 24 hours, the traps were again taken up, positive traps

18
put in vials, and red marker yarn placed in the soil to mark the bait
station until it was rebaited.
Use of Light Trap Collections
During May through August, Diplorhoptrum males and females of
S.. (2-) pergandei, (£.) carolinensis, and rarely (£.) reinerti
are attracted to light traps. Larger collections of S^. (EL)
carolinensis can be made with a light trap and a white sheet than
with a conventional, walk-in light trap. The reason for this is
unknown, but possibly a different quality of ultraviolet light is
reflected by the sheet, and thus attracts this species.
Laboratory Studies
Colony Nest Materials
Maintaining Diplorhoptrum colonies in the laboratory is extremely
difficult. Their small size and hypogaeic habits make them highly
vulnerable to desiccation. Workers of colonies in open laboratory pans
at 80% relative humidity die within 24 hours. If a colony is presented
with a moist chamber within an open laboratory pan, the workers which
forage outside the chamber will die in the open pan before they find
their way back to the colony. The colony dies by slow loss of
foraging workers.
Florida Diplorhoptrum species seem to need humidity levels of
nearly 100%, in contrast to SL (j).) molesta, and other Diplorhoptrum
species such as the unidentified Peruvian species in Dr. Ed Wilson's
laboratory at Harvard University. This species is kept in a plastic
box open to the air. Lower humidity requirements apparently allow

19
S. (D.) molesta and S. (D.) texana to forage above ground during the
day. (D_.) texana was observed in a late morning expedition to food
in a car trunk (July, 1980) at Clinton, Iowa (pers. comm., Dr. W. F.
Burn) while I have taken S_. (_D.) texana at honey baits in full sun
(June, 1980) at Cedar Falls, Iowa.
Two materials often used to maintain ant nest humidity are plaster
of paris and Castone When colonies were placed in petri dishes with
floors of either compound, workers began to go into convulsions within
a few hours, then died. An entire 5L (2-) carol inensis colony died
overnight June 3, 1980, while a IS. (_D.) pergandei colony displayed
similar symptoms the following day. The queen died two days after
exposure to these compounds, or possibly because of shock due to colony
loss. Neither species queen showed convulsive symptoms.
Colony nest humidity was finally maintained by 1) moistened cotton
floors, or 2) by using "aged" plaster of paris covering only one fourth
of the nest floor. The aged plaster was in old petri dish nests which
had been used and repeatedly washed in hot, soapy water.
The small size of the Diplorhoptrum workers allows them to escape
from any kind of petri dish. Talc and Fluon could not be used because
of the high humidity levels. When colonies were sealed in with artist's
clay, the workers gnawed 0.82 mm holes through the clay and escaped.
In colonies sealed with vaseline, many workers died overnight, ap
parently from fumes given off by this material. Finally the vegetable
fat Crisco was tried. The ants refused to cross the greasy barrier.

Crisco was subsequently placed around the inside rims of petri dishes
effectively preventing ant escapes.

20
When anlowa S_. (D.) molesta colony was placed in a Crisco
barriered nest, however, the workers began to eat the Crisco some
thing none of the Florida species had donel The colony is presently
housed in a glass jar with a screw-top lid.
Feeding
Colonies offered a selection of foods including 1:1 honey-water,
butter, raw hamburger, peanut butter, honey-agar, oil-packed tunafish,
fire ant diet (used by USDA, Fire Ant Laboratory, Gainesville, Florida),
and mealworms. S^. (J).) carolinensis fed upon the honey-agar and tuna-
fish, but largely ignored the other foods. They backed off hurriedly
from peanut butter. Mealworm larvae were killed, but did not appear to
be fed upon.
Although Sk (£.) pi eta and Sk (JD.) reinerti accepted fire ant diet
and honey-agar readily, colonies of S^. (J3.) pergandei were reluctant
feeders on all offered foods. Fire ant larvae were also offered to
this species but were refused, even when the larvae were punctured so
that haemolymph exuded. Colonies of this species could not be main
tained for more than a few months.
Queen Colony Founding
Young, newly mated females obtained from light traps were ini
tially placed in compartmented plastic boxes. Each compartment had a
moistened plaster of paris floor and sides painted with Fluon The
high humidity allowed the queens to walk over the Fluon however,
and they congregated in groups. Of 36 S_. (]D.) carolinensis, 45 S_. (D.)
pergandei and two S_. (D..) reinerti females, eight S^. (j).) carol inensis
no S.. (j).) pergandei and both S^. (JL) reinerti queens reared brood to

21
the worker stage. No (D_.) pergandei queen was able to found a
colony. Some queens laid eggs and had larvae, but died before workers
were reared.
Other materials and methods were then tried:
1. Glass tubes with moistened cotton.
2. Aged plaster of paris bottomed vials with soil above the
plaster and black paper for cover.
3. Cores of grass sod placed in vials, allowing excavation and a
more natural environment.
4. Placement in queenless laboratory colonies.
Methods 1-3 were unsuccessful. Method 4addition of queens to
queenless colonies--ended inconclusively. The females were initially
seized by the legs and antennae, but subsequently were released and
allowed to stand over the brood. Of 12 females added, six had died
before the colony had to be left unattended for two weeks. The colony
died during that time.
In summary, no satisfactory method was found for inducing queen
colony foundation in S^. (£.) pergandei. Presenting young queens with
brood or callows of their species will probably prove to be the
most useful method.
Queens of S_. (JL) carol inensis found colonies readily in plaster
of paris cups if they are allowed to remain together in groups. Queens
of S. (D..) reinerti founded colonies easily alone. It was, in fact,
the unexpected yellow workers reared by these black queens that first
convinced me that they were a new species.

RESULTS
Section I
A Taxonomic Review of the S. (Diplorhoptrum) of Florida
Introduction
No taxonomic progress has been made in the Solenopsis (Diplorhoptrum)
group for a number of years. The most recent species to be described
was S^. (jD.) longiceps by M. R. Smith in 1942. This species name was
subsequently found to be preoccupied by Solenopsis longiceps Forel, and
was changed to _S. (D.) tennesseensis M. R. Smith in 1951. The most
recent taxonomic key for the group is that by Creighton (1950) in which
he tried to define the group and synonymized several names.
Because of taxonomic and identification difficulties, most workers
have been lumping any Diplorhoptrum specimen under S_. (D.) molesta.
This species, in fact, is supposed to occur in Florida, but I have not
collected it anywhere in the state. The situation is not improved by
the fact that all of Say's types, including those of S^ (£.) mol esta
(Say), have been lost.
When a small, 100-meter square area in Gainesville was sampled and
three new species were frequently recovered, it was very apparent that
taxonomic work was needed. This study will help to prevent the "band
wagon" effect, which has gone on for many years, of labeling any
Diplorhoptrum specimen molesta. It will fill the gap left by Van
Pelt (1947) who purposely omitted the group from his Florida key
because of their uncertain taxonomy.
22

23
The four new species found during this study have the proposed
names of (JD.) "abdita11 n.sp., S_. (£.) "nickersoni11 n.sp., S_. (CL)
"reinerti" n.sp. and S.. (JL) "xenovenenum" n.sp. (Names proposed here
in quotation marks are not to be considered validly or effectively
published for nomenclatura! purposes.)

24
Key to S. (Diplorhoptrum) Species of Florida
la) Mesopropodeal constriction strong (Fig. 21); promesonotum and
propodeum, in profile, strongly convex; petiolar node placed
somewhat anterior to the petiolar-postpetiolar juncture (Fig. 23)
so that the petiole has a distinct slender posterior portion;
color uniformly dark brown or black including the appendages; an
arboreal ant found nesting in twigs and small branches of
various trees pi eta Emery
b) Lacking above combination of characters; mesopropodeal constric
tion not as strong; promesonotum and propodeum never both strongly
convex; petiolar node placed near the petiolar-postpetiolar
juncture; color usually pale yellow, or if dark, then the ap
pendages are pale; subterranean (except for one rare yellow
arboreal species) 2
2a) Head, thorax, and gaster dark brown with pale brown or pale
yellow appendages; eyes of medium size for this group of species;
with 2, occasionally 3 facets; subterranean. . nickersoni n.sp.
b) Usually entirely pale yellow to somewhat darker yellow; one
species (carolinensis) with moderate infuscations of brown on
head and gaster 3
3a) Dense pilosity on head and usually on promesonotum arising from
large, obvious punctures; eyes small or weakly pigmented or
both 4
b) Pilosity not arising from large, obvious punctures and not
noticeably dense; eyes larger or at least pigmented, the facets
surrounded by a black matrix 7

25
4a) Thorax in profile straight above; base and declivity of pro-
podeum distinguishable; head narrow and elongate, head index
79; punctures on head over entire surface, no median streak
free of punctures and hairs *tennesseensis M. R. Smith
b) Head proportionately not as narrow; head in some species with
distinct median streak free of punctures and hairs; propodeum
usually evenly rounded in profile and without distinguishable
base and declivity 5
5a) Head with obvious median streak free of punctures and hairs
(Fig. 2), in mounted specimens a median crease may also be
present in this area (but this is not evident in living or
freshly killed specimens); head elongate and narrow, head
index 89; females and males dark brown or black; head of female
trapezoidal in shape abdita n.sp.
b) Without this combination of characters; head either without
median hair-free streak, or head nearly as broad as long; head
never with median crease in mounted specimens; males and females
either light yellow or, if black, then head of female not
trapezoidal in shape 6
6a) Large species 1.8 mm in total length with head 0.429 0.009 mm
in length; head index 96; head thick and robust in profile;
shaped as in Fig. 18; males and females yellow or light
brownish yellow; wings clear and nearly colorless
pergandei Forel
b) Small species 1.1 mm in total length; head 0.318 0.002 mm in
length, head index 77; head flattened above and slender in

26
profile; males and females dark brown to black; wings heavily
and entirely infuscated with dark brown xenovenenum n. sp.
7a) Dorsal surfaces of head with moderately numerous hairs nearly
entirely of the same short length (Figs. 6, 26) 8
b) Dorsal surfaces with sparser hairs, these distinctly uneven
in length (Fig. 10) 9
8a) Rear of head and anterior portion of gaster lightly to moderately
infuscated with brown; eyes with 3 or 4 facets; females yellow
ish to light yellowish brown; female eyes very large, eye
index 41 carol inensis Forel
b) Head and gaster without infuscation; uniformly pale yellow,
some specimens nearly whitish; eyes with 2 facets; females dark
brown to black; female eyes small, eye index 33. . reinerti n.sp.
9a) Comparatively large size; body length 1.58 mm; head length
0.491 0.004 mm; head and gaster usually weakly infuscated;
subterranean *texana Emery
b) Small size, body length 1.34 mm; head length 0.363 0.003 mm;
entirely light brownish yellow without trace of infuscation
on any areas; arboreal cortical is Forel
*S. (_D.) tennesseensis and S^. (jD.) texana were not found in Florida in
the present study, and previous records seem doubtful. It is
possible that these species will eventually be found in Florida.

27
1. Solenopsis (Diplorhoptrum) abdita n.sp.
Diagnosis:
Workers pale colored, and densely covered with short hairs. Head
strongly marked with prominent punctures but with a clear median streak
free of piligerous punctures. Eyes reduced to one facet, inconspicuous.
Head broader in proportion to length than in tennesseensis, and thorax
more convex in profile. Females large and dark colored, the head
uniquely trapezoidal in shape. Wings colorless. Head and thorax with
numerous piligerous punctures.
Description:
Worker:
Measurements: Head length 0.361 0.004 mm; head width
0.32 0.002 mm, head index 89, scape length 0.235 0.003 mm,
scape index 65. Thorax length 0.444 0.003 mm, total body
length 1.56 mm. The preceding'measurements based on nine
specimens.
Structural Characters: Head longer than wide, rectanguloid
with faintly convex sides, the posterior border slightly excised
in the center. In some specimens the head is slightly more
narrow anteriorly. The eyes reduced to a single facet. Ventral
border of head moderately convex in profile. Anterior edge of
clypeus widely and angularly separated from dorsal surface of
mandible in profile. A flat head (Fig. 25) not present.
Promesonotum of thorax weakly convex in profile, propodeal
base somewhat more convex. Petiole large in profile with a

28
prominent anterioventral tooth and prominent ventral swelling
(Fig. 27). From above, petiole and postpetiole nearly equal in
width. Postpetiole with rounded sides as seen from above, not
trapezoidal. Anterioventral flange of postpetiole seen in
profile sharp but very small.
Sculpture: All surfaces smooth and shining except for head
which is heavily and densely marked with prominent punctures and
dorsum of the promesonotum which is moderately marked with weaker
punctures. Head has characteristic median streak free of punc
tures.
Pilosity: Head with numerous short hairs. Thorax, petiole,
postpetiole, legs, and gaster also with numerous short hairs
which may be longer than those on the head (Fig. 1).
Color: Entirely light yellow to light yellowish brown.
Female:
Diagnosis: A rather large, dark colored female with
colorless wings. Head distinctly trapezoidal in shape. Head
and dorsum of thorax covered with numerous strong piligerous
punctures. Differs markedly from i>. (_D.) pergandei females in
color and head shape.
Description: Head length 0.78 mm, head with 0.98 mm, head
index 126, scape length 0.67 mm, scape index 86, eye length 0.24 mm,
body length 5.5 mm.
Structural Characters: Head distinctly trapezoidal, with
nearly straight hind border and sides, the head distinctly more
narrow in front than behind. Scapes not quite reaching hind

29
corners of the head. Eyes rather small for Diplorhoptrum females.
Ocelli also small for females of this group. Petiole with blunt
node, slightly excised above as seen from behind. Postpetiole
wider than petiole, trapezoidal as seen from above, wider
posteriorly than anteriorly.
Pilosity: Head and thorax with numerous hairs arising from
strong punctures. Gastric pilosity also abundant but not arising
from punctures. A median streak on head free from punctures or
hairs as in the worker.
Color: Head, thorax, petiole, postpetiole and gaster dark
brown. Legs and antennae light greyish yellow. Wings colorless.
Male: Unknown
Types:
Holotypea worker from Gainesville, Florida, captured with a
Naves trap (June 16, 1979). Airport area. C. R. Thompson
Paratypes--numerous specimens from Gainesville Airport area, June
through September, 1979, C. R. Thompson; three workers and one female
from Tall Timbers Research Station, Florida. June, 1975. M. A. Naves.
The holotype and several paratypes will be deposited at the
Museum of Comparative Zoology. Paratypes will also be deposited in
the Florida State Collection of Arthropods, Gainesville, Florida.
Pi scussion:
This species appears superficially close to pergandei on one hand
and to tennesseensis on the other. The female, dark in color and with

30
a unique head shape, shows that the species is not close to pergandei.
The punctures on the head are stronger even than in pergandei, and the
clear median streak on the head free of punctures seems to be a constant
character which does not occur in tennesseensis. The head is narrower
in proportion to length than in pergandei but is noticeably wider than
in tennesseensis. The dorsum of the thorax is more flattened in
tennesseensis than in abdita. Scape and funiculus length shorter in
abdita than in pergandei.
This species has been found at Gainesville and Tall Timbers
Research Station north of Tallahassee. It was relatively common in
the test area near Gainesville although not as abundant as
carolinensis. The species may not be rare, but merely previously
overlooked and/or unrecognized.

31
2. Solenopsis (Diplorhoptrum) carolinensis Forel
Solenopsis texana race carolinensis Forel 1901. Ann. Soc.
Entomol. Belg. 45:345.
Solenopsis (Diplorhoptrum) carolinensis Forel. Creighton, 1950.
Bull. Mus. Comp. Zool. 104:236.
Type locality: Faisons, North Carolina
Types: Museum of Comparative Zoology, Harvard University
Range: North Carolina and Tennessee north to lower New England states
Diagnosis:
A small Diplorhoptrum with a quadrate-shaped head, moderately
sized darkly pigmented eyes. Pilosity moderate, piligerous punctures
weak. Pilosity on the head short and nearly all of the same length.
In profile, often with an anterioventral tooth on the petiole. Head
and gaster usually infuscated. Female small with large eyes.
Pi scussion:
Described as a characteristic species of North Carolina (Wheeler,
1904b) S^. (JL) carol inensis is also a common species in Florida. It is
very common in Gainesville, and was found wherever the Diplorhoptrum
fauna was sampled throughout the state. It was found in many
habitats: palmetto thickets, turkey oak, open sand areas, rocky soil
in Homestead, grassy areas, and pine woods.
The nests of this species are shallow (less than 20 cm) and
quite frequently one turn with a shovel will bring up the colony queen
with a small group of brood and workers. A colony can have more than
one queen. This species tends to forage more than most other Florida

32
species in the forest duff, and I have seen It tending mealy bugs.
Excavations of an S^. (J).) pergandei colony will often bring
(D.) carolinensis to light in the same shovelfull. The larvae of
S_. (JD.) carol inensis have a pinkish cast and are smaller than those of
S_. (JD.) pergandei.
The mating flights of this species have not been observed, but I
have dug sexual brood in June (6/9/79) and the flights occur during the
same months (June through August) as those of S.. (ID.) pergandei. The
sexual s of JJ. (JD.) carol inensis are attracted to light traps, but in
smaller numbers than JL (JD.) pergandei. The sexuals of S_. (JD.)
carolinensis fly earlier in the morning (5-5:30 a.m.).
I suspect that the Florida (JD.) molesta records, and one of
SJ. (D.) laeviceps (Smith, 1930), are based on mis identified specimens
of S^. (JD.) carolinensis. Types of this species at the Museum of
Comparative Zoology have been examined by Dr. William F. Burn.

33
3. Solenopsis (Diplorhoptrum) cortical is Forel
Solenopsis corticalis Forel, 1904. Ann. Soc. Entomol. Belg.
48:172.
Type locality: Cuba
Types: Museum d Histoire Naturelle, Geneva, Switzerland. None in this
country
Range: West Indies (Wheeler, 1913; Wolcott, 1948) and southern Florida
Diagnosis:
Small arboreal species. Head is rectangular and the eyes are
large in comparison with other species of the group. Petiole has
anterioventral tooth. Hairs are rather sparse, of uneven lengths and
do not arise from punctures. The integument is highly shining. Color
is yellow or light brownish-yellow, usually without trace of infuscation.
Discussion:
This is one of the two known arboreal Diplorhoptrum in Florida,
but appears to be much rarer than pi eta and is yellowish whereas pi eta
is black to dark reddish-brown.
Prior to this study, S_. (CL) corticalis had not been reported from
Florida. A series of this species was taken near Manalapan, a coastal
town south of Palm Beach in November, 1945, by Dr. William F. Burn.
It was found in branches of red mangrove (Rhizophora mangle L.). It was
subsequently rediscovered by Dr. J. C. Nickerson in the same habitat
in May, 1980, on Park Key. This species is polygynous and is probably
nocturnal, as no foragers were seen in the daylight. Specimens from the
Manalapan series have been compared with West Indian material at the
Museum of Comparative Zoology by Dr. William F. Burn.

34
4. Solenopsis (Diplorhoptrum) molesta (Say)
Myrmica molesta Say, 1836. Boston J. Natur. Hist. 1:293.
Myrmica minuta Say, 1836. Boston J. Natur. Hist. 1:293.
Myrmica (Tetmamorium) exigua Buckley, 1867. Proc. Entomol.
Soc. Philadelphia 6:342-3.
Solenopsis debilis Mayr, 1886. Zool.-Bot. Gesell. Wien, Verh.
36:461.
Solenopsis molesta var. validiuscula Emery, 1895. Zool. Jahrb.,
Abt. f. System. 8:278.
Solenopsis (Diplorhoptrum) molesta (Say), Creighton, 1950.
Bull. Mus. Comp. Zool. 104:237.
Type locality: Indiana
Types: No longer in existence
Range: Reported from east and central U.S. from the Gulf States to
Canada. Supposedly rare in the southern areas of the Gulf
States.
Diagnosis:
Head and thorax robust, broad in relation to length. In profile
the petiole considerably larger than the postpetiole, but seen from
above the postpetiole much wider than the petiole. Differs from
carolinensis and texana in having a distinctly broader thorax. Hairs
are sparse and of mixed lengths. No obvious piligerous punctures.
Discussion:
It is this species name which has been most abused in the litera
ture. Authors are legion (Browne and Gregg, 1969; Mann, 1911; Robbins,
1910; Rees and Grundmann, 1940; Talbot, 1975; Yensen and Clark, 1977)
who list this ant, but give little or no additional information. For

35
Florida, (2-) molesta is reported from Rockdale, in Dade County,
(Nielsson et al., 1971) where it was tending Aphis coreopsidis
(Thomas), but no further information on the biology is given. Van Pelt
(1958) reports this species from Wei aka Reserve and observed the ants
closely. He noted that what he was tentatively calling molesta did
not match specimens he had seen. Van Pelt was one of the few authors
(Mitchell and Pierce, 1912; Ross et al., 1971; Huddleston and Fluker,
1968 were others) who qualified their identifications and noted the
existing taxonomic confusion.
At this time I have found no specimens of S_. (]).) molesta in
Florida, nor have I seen any in other Florida collections. Van Pelt's
specimens are S. (D.) carolinensis.

36
5. Solenopsis (Diplorhoptrum) nickersoni n.sp.
Diagnosis:
A small dark species similar to (_D.) carol inensis in head
shape, eye characteristics, thorax, and petiole shape. Antennae and
legs pale-colored and strongly contrasting with body color.
Description:
Worker:
Measurements: Head length 0.345 0.003 mm, head width
0.30 0.002 mm, head index 86, scape length 0.241 0.003,
scape index 70, funiculus length 0.359 0.004 mm, club
length 0.222 0.002 mm. Thorax length 0.384 0.004 mm,
body length 1.2 mm. The preceding measurements based on 18
specimens.
Structural characters: Head longer than broad (Fig. 14),
rectanguloid, with weakly convex sides and straight posterior
border. Head in profile with a narrow angle between the
clypeus and mandibles. Head in profile moderately flattened.
Eyes dark in color with 2-3 facets, similar to carolinensis.
Thorax in profile (Fig. 13) with moderate meso-propodeal
suture, the dorsal outline similar to carolinensis. Petiole in
profile similar to carolinensis (Fig. 7). Petiole usually
without anterioventral teeth. From above, node of petiole a
little narrower than postpetiole. Postpetiole with trapezoidal
shape as in carolinensis. In profile postpetiole with sharp
anterioventral flange (Fig. 15).

37
Sculpture: All surfaces smooth and shining. Piligerous
punctures on dorsum of head weak and not noticeably interrupting
the surface.
Pilosity: Head with rather short, sparse hairs. Thorax
with longer hairs in moderate numbers. Gaster also moderately
beset with hairs.
Color: The head, thorax, petiole, postpetiole, and gaster
dark brown; antennae and legs, including coxae, very pale brown,
almost whitish.
Female: Unknown?
Male: Unknown?
The purported females and males of nickersoni thus far have not
been found with workers. A match was made by a process of
elimination. All other dark colored females and males occurring
in Florida have been found with conspecific workers. The dark
bodies of nickersoni contrasting with the pale colored appen
dages is a characteristic found in both the workers and the
purported females and males, but descriptions await a collection
of sexuals with workers.
Types:
Holotypea worker from Gainesville, Florida, caught in a Naves
trap on June 16, 1979. Paratype material comprises numerous workers
collected in Gainesville, Ocala, and Apopka, Florida on various dates
with Naves traps. All were collected by C. R. Thompson.

38
The holotype and several paratypes will be deposited at the
Museum of Comparative Zoology. Paratypes will also be deposited in
the Florida State Collection of Arthropods, Gainesville, Florida.
This species is named in honor of Dr. J. C. Nickerson, Division
of Plant Industry, Gainesville, Florida. Dr. Nickerson, over a period
of several years, has greatly aided and encouraged me in my
myrmecological studies.
Discussion:
([).) nickersoni is readily distinguished from all other Florida
ants of this genus by its dark color which contrasts with the light
color of its antennae and legs. In structure it is similar to
carolinensis including head shape, eye prominence, thoracic shape, and
petiole and postpetiole shape. It lacks the prominent head punctures
which are typical of pergandei, abdrta, and xenovenenum n.sp.
This species has been found in Florida at Gainesville, Ocala,
Apopka and .Myakka State Park. The species, from data collected in
1979 at Gainesville, appeared to be rare. It was caught in only one
area and in one trap position out of 100. In 1980, however, it has
been taken in April and June at nine trap locations in both open
field and wooded areas.
The venom of this species has not been analyzed.
In two instances, workers of nickersoni were attracted to a
second (or third) larval instar of Diaprepes abbreviatus (L.), the
Sugar Cane Rootstalk Borer, in a Naves trap, and were able to kill and
dismember the weevil larva. This occurred on May 13 and June 9, 1980,
near Plymouth, Florida, in a wooded area probably relatively free from

insecticides. (£.) nickersoni was not found in any citrus grove
area near Apopka or Orlando which had been treated by insecticides
herbicides.

40
6. Solenopsis (Diplorhoptrum) pergandei Fore!
Solenopsis pergandei Forel, 1901. Ann. Soc. Entomol. Belg.
45:343.
Solenopsis (Diplorhoptrum) pergandei Fore!. M. E. Smith, 1947.
Amer. Mid. Natur. 37:568.
Solenopsis (Diplorhoptrum) pergandei Forel. Creighton, 1950.
Bull. Mus. Comp. Zool. 104:237.
Type locality: Faisons, North Carolina.
Types: Museum d' Histoire Nature!le, Geneva, Switzerland. None in this
country
Range: Virginia and south to Florida, west to Louisiana.
Diagnosis:
This clear-yellow Diplorhoptrum is the largest species of this
subgenus in Florida. The worker is approximately 1.8 mm long while
the large females are 5.5 mm long. It also differs from other Florida
species in its robust head and thorax. Piligerous punctures on
head numerous and distinct. Head quadrate, only a little longer
than broad, convex dorso-ventrally in profile.
Discussion:
This species is common in Florida, and was found over the entire
state. It does not leave any surface indication of its nests except
during May through August in Florida when it constructs crenelated
tumuli the night before a mating flight (see Section 2).
This ant prefers to nest in areas which are quite dry and where
the soil is compacted such as lawns and woods trails. I have found it
in large numbers under a baseball diamond in full midday sun. In

41
Mississippi, it was nesting in soil and rotting stumps (Smith, 1931).
In Florida, Smith (1944) found it constructed small crater nests in
semiboggy ground near scrub and in loam beneath moss or pine needles.
Van Pelt (1958) found it in quite well-drained areas. Whitcomb et al.
(1972) found that it built flat honeycombed mounds about 1 foot deep in
canefields. He observed that the species seemed to be thriving and
was strictly nocturnal. The Whitcomb et al. observations seem
questionable for S^. (D.) pergandei and may be based upon a misdeter-
mination.

42
7. Solenopsis (Diplorhoptrum) picta Emery
Solenopsis tenuis Ma.yr, 1886. Zool-Bot. Gesell. Wien, Verh.
36:262. Nec. S_. tenuis Mayr 1877.
Solenopsis picta Emery, 1895. Zool Jahrb., Abt. f. System. 8:278.
Solenopsis picta var. moerens Wheeler, 1915. Bull.Amer. Mus.
Natur. Hist. 34:393.
Solenopsis (Diplorhoptrum) picta. Creighton 1950. Bull. Mus.
Comp. Zool. 104:237-238.
Type locality: Florida
Types: Museo Civico di Storia Naturale "Giacomo Doria," Genoa, Italy
Range: Gulf States from Florida west to Texas
Diagnosis:
An arboreal species living in tree twigs. It has a strong
mesopropodeal impression, and the promesonotum and propodeum are
both strongly convex in profile. Petiolar node set forward from the
petiolar-postpetiolar juncture. Hairs are sparse, and of various
lengths, and do not arise from punctures. The body shining. Color
black, including appendages. A color variant occurs which is paler,
often reddish brown.
Di scussion:
This species is common throughout Florida and the southeastern
states, but is limited to habitats with dead wood and twigs in which to
nest. It is a polygynous species, easily reared in the laboratory.
I have a colony captured two years ago, July 23, 1979, which
produced sexuals this past May. The sexuals are not attracted to light
traps. Van Pelt found this species most commonly in bayhead areas (1958).

43
8. Solenopsis (Diplorhoptrum) reinerti n.sp.
Diagnosis:
A small pale species. Eyes small but darkly pigmented. General
characters of workers similar to carolinensis, but queens dark in
color except for pale appendages, with small eyes and ocelli.
Description:
Worker:
Measurements: Head length 0.336 0.003 mm, head width
0.285 0.003 mm, head index 85, scape length 0.225 0.003 mm,
scape index 67, funiculus length 0.332 + 0.006 mm, club length
0.207 0.004 mm. Thorax length 0.359 0.004 mm, body length
1.58 mm. The following measurements based on 12 specimens.
Structural characters: Head quadrate, longer than broad
with weakly convex sides and straight posterior border. Eyes
small but pigmented, with two or three facets. Mandibles with
four teeth.
Thorax similar in structure to carolinensis. Propodeum
smoothly rounded in profile without definite base or declivity.
Petiole similar in shape to that of carolinensis but without
ventral concavity and the anterioventral teeth characteristic
of carolinensis (Fig. 27). Postpetiole a little wider than
petiole seen from above and weakly trapezoidal as in
carolinensis. Postpetiole shorter in proportion to length
than in carolinensis.

44
Sculpture: Head with noticeable but small punctures,
these much weaker than in pergandei, tennesseensis, abdita,
or xenovenenum n.sp. Remainder of integument smooth and
shining.
Pilosity: Head with numerous short hairs, thorax with less
numerous, somewhat longer hairs.
Color: Pale yellow or very pale brown, the integument
largely transparent.
Female:
Measurements: Head length 0.54 mm, head width 0.54 0.002 mm,
head index 100, scape length 0.40 mm, funiculus length 0.52 mm,
scape index 74, body length 2.7 mm.
Structural characters: Head as long as broad with convex
sides and straight or very slightly concave posterior border.
Clypeal teeth weak. Mandibles each with four teeth. Eyes and
ocelli small.
Thorax distinctly narrower than the head. Petiole with a
high node, and without anterioventral teeth. Postpetiole with
anterioventral flange. Wider than petiole as seen from above
and weakly trapezoidal.
Sculpture: Head with numerous well marked punctures. These
are weaker but noticeable on the thorax.
Pilosity: All surfaces with numerous hairs of moderate
length.
Color: Head, thorax, petiole, postpetiole, and gaster dark
brown. Mandibles, scapes, funiculi, and legs pale yellow or
pale brown.

45
Male: Unknown
Types:
Holotype a worker taken by core sod sampling in Dade County,
Florida, on July 29, 1974, by J. A. Reinert. Paratypes are numerous
workers and females collected by J. A. Re inert. Other paratypes are
one female (and workers later reared by her) collected on June 23,
1979, in Gainesville, Florida, by C. R. Thompson.
The holotype and several paratypes will be deposited at the
Museum of Comparative Zoology. Paratypes will also be deposited in
the Florida State Collection of Arthropods, Gainesville, Florida.
This species is named in honor of J. A. Reinert who was the first
to capture this cryptic new species.
Pi scussion:
Very little is known about this new species. J. C. Trager
(Department of Entomology and Nematology, University of Florida) found
sexuals and workers of this species beneath a stone at the edge of woods
on June 29, 1980. He collected reinerti males at a blacklight at
5:45 a.m. on June 26, 1980.
The workers of this species are so similar to those of carolinensis
that identifications remain questionable if only workers are available.
The dark brown to black female, however, is so different from the
large-eyed, reddish-yellow female of carolinensis that it is clear that
two taxa are involved. Although presently known from only two Florida
localities, the species may prove to be common and widespread.

46
9. Solenopsis (Diplorhoptrum) tennesseensis M. R. Smith
Solenopsis (Diplorhoptrum) longiceps M. R. Smith, 1942. Proc.
Entorno!. Soc. Wash. 44:210. Preoccupied by Forel,1907.
Solenopsis (Diplorhoptrum) longiceps M. R. Smith. Creighton,
1950. Bull. Mus. Comp. Zool. 104:236-236.
Solenopsis (Diplorhoptrum) tennesseensis M. R. Smith, 1951.
In Muesebeck, U.S.D.A. Agr. Monog. 2:814. N. name.
Type locality: Hamilton Co., Tennessee.
Types: United States National Museum, Washington, D. C.
Range: Florida west to Texas and north to latitude of Tennessee.
Diagnosis:
We did not find this subterranean species in Florida in spite of
previous records. It has probably been confounded with the new species
S.. (D.) xenovenenum. S^. (j3.) tennesseensis is unusual in having a
slender head. The thorax in profile is straight dorsally and the
propodeum has a distinct base and declivity. Head and thorax with
numerous short hairs arising from distinct punctures. It differs from
.S* (JD.) abdita in not having a clear median streak free from punctures
and hairs on the head.
Discussion:
This study has shed no new light on the biology or distribution
of S^. (D.) tennesseensis. Little information is present in the
literature. This species is known primarily from the type series.
The range given by Creighton (1950) may not be accurate.

47
10. Solenopsis (Diplorhoptrum) texana Emery
Solenopsis pollux var. texana Emery, 1895. Zoo! Jahrb., Abt. f.
System. 8:278.
Solenopsis texana Fore!, 1901. Ann. Soc. Entomol. Belg. 45:345.
Solenopsis rosella Kennedy, 1938. Can. Entomol. 70:232.
Solenopsis (Diplorhoptrum) texana Creighton, 1950. Bull.
Mus. Comp. Zool. 104:238.
Type locality: Texas
Types: Museo Civico di Storia Naturale "Giacomo Doria", Genoa, Italy.
A questionable series is at the Museum of Comparative Zoology at
Harvard.
Range: Central Texas and southeastern states north to Canada
Diagnosis:
Similar to molesta, but head more slender, thorax distinctly more
slender. Postpetiole a little wider than the petiole seen from above.
Hairs sparse and of mixed lengths. No piligerous punctures. Head and
gaster often weakly infuscated.
_S. (JL) texana is larger than carolinensis and the hair patterns
are different. The small females with the very large eyes seem to be
unique to carolinensis.
Discussion:
I have not been able to find this species in Florida. Although
Krombein et al. (1971) list this species from Florida, I suspect exam
ination of the specimens would show them to be carolinensis. Authentic
specimens of S.. (D.) texana may eventually be found in the state.

48
11. Solenopsis (Diplorhoptrum) truncorum Forel
Solenopsis texana race truncorum Fore!, 1901. Ann. Soc.
Entorno!. Belg. 45:346.
Solenopsis molesta var. castanea Wheeler, 1908. Bull. Amer.
Mus. Natur. Hist., 24:430.
Solenopsis (Diplorhoptrum) truncorum Creighton, 1950. Bull.
Mus. Comp. Zool. 104:239.
Type locality: Faisons, North Carolina
Types: Museum d'Histoire Naturelle, Geneva, Switzerland.
Range: Southeastern U.S. and west to the Rocky Mountains.
Diagnosis:
A large, dark-colored species with rather sparse scattered hairs
of mixed lengths. This species is common in the mountains of the
western U.S., but also occurs in the eastern Appalachian Mountains.
Discussion:
The large dark brown castanea was synonymized under truncorum
by Creighton (1950). No types of truncorum are present in this country,
but the types of castanea were compared with various Florida species
by Dr. William F. Burn. The Florida specimens did not match the
types of castanea.
I have not found this species in Florida, although Smith (1979)
lists the species as occurring in this state.

49
12. Solenopsis (Diplorhoptrum) xenovenenum n.sp.
Solenopsis tennesseensis Krombein, Hurd, Smith, Burks.
Catalog of Hymenoptera in America North of Mexico.
Smithsonian Institution Press, Washington, D.C.
1979. p. 1388. in part, nec M. R. Smith
Diagnosis:
Very small yellow species. Head with prominent punctures,
pilosity short and numerous on all surfaces. Head elongate as in
tennesseensis. Eyes reduced to a single facet. Males and females
with characteristic darkly infuscated wings.
Description:
Worker:
Measurements: Head length 0.317 0.002 mm, head width
0.245 0.002 mm, head index 77, scape length 0.191 0.002,
scape index 60, funiculus length 0.296 0.003 mm, club
length 0.191 0.002 mm. Thorax length 0.336 0.004 mm, body
length 1.1 mm. The preceding measurements based on 18
specimens.
Structural characters: Head (Fig. 30) distinctly longer
than broad with weakly convex sides and straight or slightly
excised posterior border. Antennal scapes reaching 2/3 the
distance from insertions to hind corners of head. Eye reduced
to one facet, usually pigmented. In profile head somewhat
flattened dorsally, slightly convex ventrally. Anterior edge
of clypeus angularly separated from dorsal surface of mandibles
seen in profile.

50
Thorax weakly convex; propodeum rounded without definite
base or declivity (Fig. 29). Petiole without anterioventral
tooth. From above the petiole and postpetiole are about the
same width. Postpetiole with rounded sides.
Sculpture: Dorsum of head covered with distinct punctures
but these not as strong as in tennesseensis or abdita. Dorsum
of promesonotum also with some weak punctures. All other
surfaces smooth and shining.
Pilosity: Hairs short and numerous on all surfaces.
There may be some longer hairs on the thorax, gaster, and petiole.
Color: Yellow to pale yellowish brown.
Female:
Measurements: Head length 0.59 mm, head width 0.64 mm, head
index 108 mm, scape length 0.46 mm, scape index 78, funiculus
length 0.60 mm, total body length 3.24 mm.
Structural characters: Head quadrate, a little longer than
broad with both sides and occipital border nearly straight or
only slightly convex. Scapes nearly reaching hind corners of
the head. Ocelli rather small, measuring 0.02 mm in diameter
and separated from each other by at least one diameter.
Thorax slightly narrower than head. Petiole without
anterioventral tooth. Node of petiole with slightly excised
superior border seen from behind. Petiole and postpetiole of the
same width. Postpetiole weakly trapezoidal as seen from above,
wider posteriorly than anteriorly.

51
Sculpture: Head with scattered moderate punctures;
mesonotum with weak punctures. Pleurae of propodeum, petiole,
and postpetiole weakly striate or shagreened. All other
surfaces smooth and shining.
Pilosity: Body and appendages with numerous short hairs.
Wings with dark brown veins and stigma, membranes also com
pletely infuscated with brown.
Color: Entire body including appendages brownish to dark
brown.
Male:
Measurements: Head length 0.40 mm, head width (including
eyes) 0.50 mm, thorax length 1.08 mm, petiole length 0.34 mm,
eye length 0.19 mm, body length 2.82 mm.
Structural characters: Antennae 12-jointed, last two joints
and particularly the last joint longer than other funicular joints,
but not enlarged or clublike. Eyes occupying about one-half of
head length, ocelli 0.065 mm in diameter. Mandibles weak, each
with 2 or 3 teeth. Head trapezoidal in shape.
Thorax without Mayrian furrows on the mesonotum. Petiolar
node with slightly concave superior border.
Sculpture: Head and dorsum of thorax with weak punctures.
Propodeum sculptured with striato-punctate markings. Petiolar
node punctate.
Pilosity: All surfaces with numerous short hairs.
Color: Dark brown, including the appendages. Wing veins
and membranes completely infuscated with brown.

52
Types:
Holotypea worker collected by Naves trap on June 16, 1979, by
C. R. Thompson. Paratypes are numerous workers taken in Naves traps
June to October, 1979.
The holotype and several paratypes will be deposited at the
Museum of Comparative Zoology. Paratypes will also be deposited in
the Florida State Collection of Arthropods, Gainesville, Florida.
Discussion:
This species is so named because it was found by Dr. Tappey Jones
(Univ. of Georgia) to have (5Z,8E)-3-heptyl-5-methyl pyrrolizidine as
the main constituent of its venom. This compound is new to biology.
The species is common throughout the state in many habitats.
Males and females have been observed in an afternoon flight at
Homestead, Florida, in July, 1964. Males have been taken from a spider
web in Gainesville, Florida, on July 30, 1978, and from a light trap in
Miami Beach (June 3, 1947). This is the smallest Diplorhoptrum species
in the United States and has been taken from under stones, unlike most
other species of the subgenus in Florida.

PLATE 1
Figure 1. Lateral view of worker of S.. (D^) abdita n. sp.
(65X)
Figure 2. Head of the worker of (J).) abdita n. sp.
(120X)
Figure 3. Petiole and postpetiole of worker of (D.)
abdita n. sp. (340X)
Figure 4. Dorsal view of worker of S_. (D^.) abdita n. sp.
(50X)

54

PLATE 2
Figure 5
Figure 6
Figure 7
Figure 8
Lateral view of worker of (JD.) carol inensis
Fore! (60X)
Head of the worker of S^. (]).) carol inensis Forel
(130X)
Petiole and postpetiole of worker of S_. (£.)
carolinensis Forel (290X)
Dorsal view of worker of ([).) carolinensis Forel
(56X)

56

PLATE 3
Figure 9
Figure 1
Figure 1
Figure 1
Lateral view of worker of S_. (JD.) cortical is Fore!
(90X)
Head of the worker of S_. (j).) cortical is Forel
(200X)
. Petiole and postpetiole of worker of S^. (J).)
cortical is Forel (360X)
. Dorsal view of worker of S^. (J3.) cortical is Forel
(65X)

58

PLATE 4
Figure
Figure
Figure
Figure
13. Lateral view of worker of $k (JD.) nickersoni n. sp.
(75X)
14. Head of the worker of S. (D.) nickersoni n. sp.
(120X)
15. Petiole and postpetiole of worker of S_. (JD.)
nickersoni n. sp. (420X)
16. Dorsal view of worker of S_. (D_.) nickersoni n. sp.
(65X)

60

PLATE 5
Figure 17. Lateral view of worker of S_. (J3.) pergandei Forel
(79X)
Figure 18. Head of the worker of S.. (jD.) pergandei Forel
(98X)
Figure 19. Petiole and postpetiole of worker of S^. (]3.)
pergandei Forel (165X)
Figure 20. Dorsal view of worker of S_. (JD.) pergandei Forel
(75X)

62

PLATE 6
Figure 21. Lateral view of worker of S_. (_D.) pi eta Emery
(7 OX)
Figure 22. Head of the worker of S^. (I).) pi eta Emery
(140X)
Figure 23. Petiole and postpetiole of worker of S. (JL)
pi eta Emery (378X)
Figure 24. Dorsal view of worker of S_. (D_.) pi eta Emery
(70X)

64

PLATE 7
Figure 25. Lateral view of worker of (J3.) reinerti n. sp.
(90X)
Figure 26. Head of the worker os (DL) reinerti n. sp.
(140X)
Figure 27. Petiole and postpetiole of worker of S^. (13.)
reinerti n. sp. (460X)
Figure 28. Dorsal view of worker of S^. (J3.) reinerti n. sp.
(50X)

66

PLATE 8
Figure 29. Lateral view of worker of S_. (£.) xenovenenum n. sp.
(83X)
Figure 30. Head of the worker of S^. (JD.) xenovenenum n. sp.
(150X)
Figure 31. Petiole and postpetiole of worker of S^. (D^.)
xenovenenum n. sp. (460X)
Figure 32. Dorsal view of worker of S_. (ID.) xenovenenum n. sp.
(84X)

68

PLATE 9
Figure 33. Cluster of mating flight tumuli of S_. (j).) pergandei
Forel
Figure 34. Mating flight tumulus of S_. (CL) pergandei Forel
Figure 35. Mating flight tumulus of S. (J3.) pergandei Forel


71
Section II
Subterranean Distribution of Diplorhoptrum Species
Mosaic distribution of ant species is well documented in cacao
plantations (Majer, 1972; Leston, 1973), but these studies involved
arboreal species in easily sampled ecological niches, i.e., cocoa trees.
Nothing was known of the distribution of Diplorhoptrum species below
ground, particularly as no surface structures are constructed by these
ants, with the exception of (j).) pergandei mating flight tumuli.
Accordingly, 5x10 meter grids were set up, and experimental
trapping was begun in June, 1979. The results were immediate and
surprising. Of 100 traps put down June 17, in 24 hours 59 were positive
for ants and, of these, 43 contained Diplorhoptrum. Diplorhoptrum were
captured in as many as 75 per cent of the traps during July and August
and as few as 3 per cent in January. Some traps contained over 300
ants. An example of the results is shown in Fig. 36 for the longleaf
pine-turkey oak woods. Five species of Diplorhoptrum were captured in
the traps during this study. All were present in the first set of
traps put down on June 17. Numbers of traps in which each Diplorhoptrum
species was captured throughout the year are presented in Figs. 37 and
38.
It is evident that S.. (D.) carol inensis was the dominant subterran
ean ant in both habitats. S_. (]D.) pergandei was absent from the field
habitat, and present at only two trap locations in the woods grid. Si. (D.)
xenovenenum also had a distinct pattern in that they were captured in
only 2 traps in the field, but were evenly distributed in the wood.

72
S3
S.
(D.)
nensis
m
S.
(D.)
venenum
m
S.
(D.)
n.
sp.
S.
(D.)
Other genera
Figure 36.
Example of Naves trap samples
other species distribution in
turkey oak woods on June 24,
Florida.
of Diplorhoptrum and
a long leaf pine-
1979, at Gainesville,

73
3 S. (D.) carol inensis
S. (D.) abdita n. sp.
ffiS. (D.) xennvenenum n. sp.
S. (£.) pergandei
S. (D.) nickersoni n. sp.£
10
T / / / ////// / /
/ / / / / / / / / / / /
/ / / / / / / / / '
/ / / / / / / / /
/ /
L.
! / /
/
/
/
JJASONDJFMAMJ
1979 Month 1980
Figure 37. Diplorhoptrum species captured by Naves trap in
an open field at Gainesville, Florida, from June
1979-June 1980.

74
t3S_. (D_.) carol inensi s
S_. (JD.) abdita n. sp.
(D_.) xenovenenum n. sp.
Figure 38. Diplorhoptrum species captured by Naves trap in
a long leaf pine-turkey oak woods at Gainesville,
Florida, from June 1979-1980.

75
Ant activity dropped sharply between October and November and began
to increase the following year between April and May. Having observed
the sharp cessation of activity in the fall, I suspected soil tempera
tures might be a factor and began to monitor them. On April 15 the
field soil temperatures taken at 14 cm were 15.3, 16.3 and 17.0 C.
The wood soil temperatures were 16.0, 16.3 and 17.0 C. By May 16 a
distinct increase was evident: field soil temperatures were 23.3, 23.3
and 24.0 C while wood soil temperatures were 21.0, 21.5 and 21.50 c.
These data indicate that soil temperature may be a major factor in
seasonal Diplorhoptrum activity patterns.
The major question posed by these collection data is how many nests
and of what species are present? Estimates of colony numbers and
territorial sizes can be made based on the following assumptions:
1. Few ant species build one-chambered nests, and all known
Solenopsis build multi-chambered nests. It can be assumed Diplor
hoptrum have multi-chambered nests.
2. All known Solenopsis have discrete nests. Large populations
covering large areas without discrete nests probably do not occur in
Diplorhoptrum species. Diplorhoptrum are here assumed to have discrete
nests and foraging areas which do not extensively overlap.
3. From the appearance of S_. (D.) pergandei tumuli clusters, which
are constructed following rain (Fig. 33), the network of chambers and
tunnels below may be assumed to be diffuse. The nest probably occupies
a region comparable to the size of the cluster on the surface and not
more than 1 or 2 meters in area.
4. Each ant colony controls available food sources over as wide
an area as possible. Dominant species may be assumed to control large

76
areas; subdominants to control proportionately smaller areas.
5. Whether dominant or subdominant, the closer a food source is
to a nest, the more likely that colony will be able to successfully
exploit and control the food source.
6. Subdominants or non-dominants probably can not maintain
complete control over foraging areas unless near their nests. Specific
traps (i.e., Meter 8 with S^. (D.) nickersoni or Meters 70 and 71 (Fig. 37)
with 5L (£.) pergandei) were nearly always positive with certain
subdominants, therefore it is probable that these traps were located
near a nest of the subdominant, and that a single colony of the sub
dominant is indicated by each of these locations.
7. It can be assumed that any trap location in which one species
was consistently collected and which was nearly always positive is
likely to be close to the nest location of a dominant.
Therefore the nest of each subdominant, and the nest areas of each
dominant should be countatfe with reasonable accuracy. With these
assumptions, and the summation method of assembling che data, the
nesting pattern and general foraging areas of the various species
sampled can be estimated. Data were summed by counting the numbers of
traps positive for each species, then multiplying each number by the
percentage of the time a trap was positive for that species. For
example, S_. (j).) carol inensis was present, in Trap 12,5 out of 7 or
77.7% of the times that the trap was positive with Diplorhoptrum.
Multiplying 5 x 77.7% gives an experimental summation number of 544.
The summation numbers were then arbitrarily divided into four groups and
assigned to a pattern series, as shown in Figs. 39-43. From these
patterns, rough estimates of the shape of foraging areas for each
individual nest can be drawn.

77
S_. [D_.) carolinensis mosaic patterns were the most complex. In the
field there appear to be four colonies with wide-ranging territories
(Fig. 39). Foraging areas of two additional colonies appear to be only
partially present in the grid. In the woods site, there is probably
one large colony and a second smaller colony with a much smaller
foraging area around Meter 82 (Fig. 41).
The colony and foraging patterns of S^. (I).) abdita and S^. (D_.)
xenovenenum are less complex. There appear to be 4 colonies of S_. (J).)
abdita in the field grid and only probably two colonies in the woods,
with perhaps an incipient colony in Meters 84-85 (Figs. 40,42). S^. (ID.)
xenovenenum occupied only one meter in the field site, but appeared to
have three colonies (Fig. 43) and part of the foraging territory of a
fourth in the woods site.
The data in Figs. 39-43 are subject to more than one interpretation
and boundaries could easily be drawn somewhat differently. In addition,
the true correlation of colony numbers and territories indicated by
trapping data with those actually present in the field remains unknown.
It is hoped that the Naves trap method may eventually be found to
indicate true Diplorhoptrum territories and colony numbers.
In the field site S^. (D.) carol inensis is the dominant species while
S. (£.) pergandei is an occasional dominant, or to use Majer's (1972)
terminology sensu strictu, a sub-dominant, i.e., a species capable at
times of becoming a dominant. Yet many more S^. (J3.) pergandei queens
were found during field excavation and in light traps than were S. (J).)
carolinensis. This would be consistent with a species which does not
expend energy in large queens and mating flights, but whose small queens
may mate mostly in the nest and remain in the nest to produce large,

78
diffuse colonies. Dr. J. C. Nickerson collected a colony of S_. (£.)
carolinensis which had 6 queens. In the laboratory a number of 2- (2-)
carolinensis queens will found a nest together amicably, and will
remain together without-fighting after workers are reared. These data
support the low energy--small queens hypothesis.
A second method of data analysis undertaken was a breakdown of
positive trap counts by month of the year as shown in Figs. 44 and 45.
Concentrations and suspected nest locations generally coincided with
those obtained from the summation method. Comparisons must be made
with caution, however, as data presented in Figs. 44 and 45 cover a
year while Figs. 39-43 include data from a five month period.
The greatest weight was placed on the five month summation study
results, after the tremendous fluctuations in species location data
were noted. Fluctuation in colony locations was greatest following the
relative inactivity of the winter months. Twenty traps remained
positive for the same Diplorhoptrum species over the entire year.
Intramonthly repeatability (June to Oct.) was high: 90% + 2.0, while
intermonthly repeatability was substantial: 63% + 3.0. The number of
traps common to the same species on June 17, 1979 and June 18, 1980
(first and last experimental dates) was eight, while the number of
corresponding traps with different species was 11 and the remaining
traps were positive on only one day or not at all.
In addition to the summation and by^month analyses of Diplor
hoptrum distribution, a third method was proposed based on the
following observations and hypothesis: during November through
February, Diplorhoptrum activity was low, with S. (D.) pergandei and
S. (D.) abdita activity ceasing entirely. If one makes the assumption

79
Summation Values
o-300
301-600
HD 601-1,000
l,000+
Figure 39. Five month (June-Oct., 1979) summation of the
distribution by trapping of (D_.) carol inensis
in an open field at Gainesville, Florida.

80
Summation Values
CD 0-50
O51-200
[HD 201 -700
Figure 40. Five month (June-Oct., 1979) summation of the
distribution by trapping of (]}.) abdita
in an open field at Gainesville, Florida.

81
Summation Values
(ZDo-300
0301-600
ED 601-1 ,000
[11 ,000+
Figure 41. Five month (June-Oct., 1979) summation of the
distribution by trapping of S_. (D_.) carol inensis in
a long leaf pine-turkey oak woods at Gainesville,
Florida.

82
Summation Values
CD 0-50
CDD 51 -200
El] 201 -700
11700+
Figure 42. Five month (June-Oct., 1979) summation of the
distribution by trapping of S_. (D.) abdita in a long
leaf pine-turkey oak woods at Gainesville, Florida.

83
Summation Values
mo-50
[ED 51-200
HD 201 -599
U 600+
Figure 43. Five month (June-Oct., 1979) summation of the
distribution by trapping of (ID.) xenovenenum
in a long leaf pine-turkey oak woods at Gainesville,
Florida.

84
'
20

21
A
40
A
41
A
2

19
A
22
39

42
A
3

18

23

38
A
43
A
4
A
17
A
24
A
37
A
A
on

16
A
25
A
36
A
45

6
A
15

26

35

46
A
7
A
14
A
27
A
34

47
.A
8
A
13
A
28
A
33
A
48
A
9

12
A
29

32
A
49
A
10
A
ii

30
A
31
A
50
A
S_. (_D.) carol i -
^ nensis
/\ S_. (D_.) abdita
Figure 44. Number of months each trap site in an open field
at Gainesville, Florida, was positive for three
j.m three species of Diplorhoptrum (June 1979-June 1980).

85
51
A
21
31
E
30
m
31
E
52
e
f!
m
22
E
39
m
32
E
53
AE
63
23
"
E
33
34
A E
32
E
24
2
32
m
34
55
A
6B
25
2
33
E
35
E
55
ss
2t
e
35
E
36
E
s'
S4
E
22
E
34
B
32
E
51
E
S3
E
21
E
33
E
33
E
ss
E
B
A E
23
A
32
E
33
E
st
A
"
A B
11
A E
"
E
111
E
/~\S_. (ID.) carol i-
w nensis
/\ S. (JD.) abdita
ii S_. (ID.) xeno-
1I venenum
Figure 45. Number of months each trap site in a long leaf pine-
turkey oak woods at Gainesville, Florida, was positive
for three species of Pi piorhoptrum (June 1979-June 1980).

86
that the ants do not forage far from the nest in the cold, it should be
possible to map nest locations more accurately than at other times of
the year.
When the winter distribution maps were prepared, however, it was
found that many traps were positive, but only once or twice, making
pattern discernment impossible.
Figures on the distribution of :S. (]}) pergandei and S^. (JD.)
nickersoni were not included, as these species were extremely localized.
5L (J).) pergandei appeared only in woods traps with one established
nest in or near Meter 70, which included territory in Meters 69-72.
S_. (JD.) pergandei is a sub-dominant. It successfully excluded SL (JD.)
carolinensis from Meter 70 for an entire year. SL ([).) nickersoni
appeared to have an even more scattered distribution except for captures
by Traps 8 and 13. It is also a sub-dominant, able (Fig. 40) to
exclude S^. (D.) carol inensis from Meter 8, but not S_. (I).) abdita.
Only Diplorhoptrum species were taken from the field traps in this
study, but other ant genera came to the woods traps: Pheidole dentata,
Pheidole floridana, Pheidole metallescens, Brachymyrmex depilis and (one
collection) Solenopsis geminata. Records of these ants were kept but
are not included in this study. It is evident from the approximately
3 to 14% of the traps which captured this group, that the greatest
competitors Diplorhoptrum have among other ants are species of Pheidole.
In summary, totally unexpected and extremely large numbers of
workers of five Diplorhoptrum species were found in an open field and in
long leaf pine-turkey oak woods. Three of the species were new. By
constructing a system of assumptions and by summing numbers of positive
traps and percentage of those traps for each species, diagrams of

87
possible nest numbers and territorial boundaries were constructed.
(£.) carolinensis was the dominant species in both habitats while
(]).) abdita was common, particularily in the field. Of the less
conmon species, (ID.) xenovenenum was more often found in the woods,
_S. (]).) nickersoni was rare in both habitats and S^. (]).) pergandei was
only in the woods site. This was a beginning study of previously
unknown or poorly known species. From the preliminary data no habitat
preferences for the various species should be inferred at this time.

88
Section III
The Mating Flights of S. (D.) pergandei
Solenopsis (Diplorhoptrum) pergandei is the largest species of the
subgenus that occurs in Florida. It is also the only species that
constructs a visible structure (tumulus) surrounding its nest opening
at the soil surface. From June through early September, within 24 hours
after a rain, S_. (JD.) pergandei constructs unique, crenelated tumuli
for early morning mating flights.
Tumuli Construction
The tumuli are constructed with passages wide enough for several
females to pass (ca. 6 mm ) and with walls twice or more their body
height (ca. 5-10 mm). I have seen some tumuli 16 cm in diameter. One
benefit of these passages is probably an increase in the number of
sexuals that can remain at the soil surface in preparation for a flight
while still remaining under the protection of the workers. On June 23,
1979, at 4:20 a.m., I observed sexuals massed at the surface even
though this flight did not occur until nearly 6 a.m.
A second function of these tumuli is probably to present a flight
take-off surface for the departing sexual forms, although I have
observed the heavy females climbing up grass blades near the nest.
On morning when flights did not occur, the ants constructed tumuli
of two additional types. These I have called "closed" tumuli and
"digging-cut" tumuli. The closed tumuli were sometimes constructed on

89
mornings following rain when flights did not occur. The ants constructed
chambers at ground level, then formed a thin roof of soil pellets with
worker-sized entrances. No flights were ever observed from these
structures.
Digging-out tumuli apparently were for exactly that purpose. Other
conditions apparently were not favorable for flights, and the ants were
most likely repairing passages which had collapsed with the rain. These
tumuli were simply piles of excavated soil deposited near the entrance.
Flight Factors
Preliminary studies in the summer of 1978 suggested that S^. (£.)
pergandei mating flights did not occur unless there had been measurable
precipitation during the previous 24 hours. Data gathered on 30 flights
from June to September of 1979, when they ceased in the Gainesville
area, showed that 83% (25) of the flights occurred following a rain.
On seven additional mornings tumuli were constructed but no flights
occurred. The ants frequently constructed closed, digging-out and a
few crenelated tumuli on non-flight mornings. This indicated that con
ditions became unfavorable during the night, or that additional stimuli
utilized by the ants to initiate flight were not favorable.
As the summer progressed, mating flights occurred slightly later
each week. In late June, flights began at 5:50 a.m. In early August,
they were beginning at ca. 6:08 a.m. This suggested that an additional
factor potentially triggering flights was light. A commercial light
meter was used to attempt light readings at flight times. It was so
dark in the half hour before dawn when these ants flew that almost no
light values were registered. Readings at 6:41 a.m., shortly after a

90
flight on September 3, 1979, were 0.05 fc with the probe at ground
level facing the sky, 1.0 fc facing the eastern horizon, and 1.6 fc at
45 to the horizon.
As an alternative to direct light readings, the flight times were
recorded and compared with local sunrise times (Fig. 46). Actual
flight times recorded were few. I attempted to watch 10-30 nests and
rarely saw the actual beginning of a nest flight. It was also so dark
that a flashlight had to be used to observe flight activity. It was
turned on for a few seconds every five minutes to ascertain flight
activity while attempting to keep interference to a minimum. I did
notice that I was able by summer's end to arrive at 5:45 a.m. and not
miss any of the flights. The graph in Fig. 46 does indeed show a corre
lation of flight times with time of sunrise. As the days shortened,
the flights occurred later in the morning and remained at ca. one half
hour before dawn. The occurrence of the wood flights, where dawn was
slow to penetrate, at later times than the open meadow flights, also
points to light as a triggering factor.
Flight and Post Flight Activities
When moisture and light levels are favorable, a final unknown
stimulus (or stimuli) causes the workers in a S_. (D.) pergandei nest to
begin running about erratically. The winged sexuals become excited and
begin to leave the nest. No nest was observed to contain both sexes.
Rather, only winged males or winged females were present. The nests
containing winged males began flight first. The males, with their
smaller and lighter bodies, were quickly in flight. In nests with
females flight times were longer. The larger, ponderous females were

710
650'
640
en
c
r
£ 630
O
E
O 620
OI
E
610
550
540-1
F=Field flight
B=Beginning of field flight
E=End of field flight
wF=Woods flight
wE=End of woods flight
*-~-=Sunri se
{wf
I I I I I I I I I I I I I I I I I I I I 1 I I I I I I I I I I 1 I 1 I I I I I I I -L 1 1 I 1--It I II 1 I I I I III I L 1 I -I
26 30 4 8 12 16 20 24 28 1 5 9 13 17 21 25 29
June
July
August
Date (1979)
Figure 46. Correlation of (j).) pergandei mating flights with times of sunrise in Gainesville,
Florida.

92
also more exposed to predators by their slowness to take wing. I saw
both Pheidole workers (June 10, 1979) and a worker of Odontomachus
brunneus (Patton) on June 26, 1979, carrying off S_. (D_.) pergandei
females.
Much predation is probably avoided by the erratic movements of the
workers. The impetus of worker movements caused them to spread out by
the hundreds over the tumulus and within a radius of approximately 5 cm
around it. In this area they frequently confronted workers of other
species of ants which were immediately attacked. As a result, the large
females were protected by a network of workers within the tumulus area.
Although the activities of the workers protected the females quite
adequately, after the flight the nest was exposed to extreme danger.
The workers did not always close colony entrances and often could be
found on the soil surface until midmorning. On three occasions I ob
served a S^. (]}.) pergandei nest being destroyed by Solenopsis geminata.
I suspect that the only reason more S^. (£.) pergandei nests were not
attacked was that, after the sun reached them, the tumuli rapidly began
to crumble. By 10 a.m. it was virtually impossible to determine whether
a flight had occurred: the tumuli had crumbled to a layer of powdered
dust on the soil surface.
An unexpected observation was the number of flights which were
staged from single nests. Nest locations were stable throughout the
summer and workers constructed a new tumulus where the old one had
collapsed or had been obscured by rain. It was not uncommon for flights
to be initiated from a nest every favorable morning for two months or
more. I observed one nest from which sexuals flew for nearly the
entire summer.

93
Initially I hypothesized that mated females were accepted by
existent colonies after a flight. Nests near the flight study area
contained as many as 20-30 deal ate females which I thought were
reproducing queens. Observation of nests which had initiated mating
flights for several weeks gave another explanation: females were
observed with three wings, two wings, one wing and no wings at all
during flights. These females, even those with no wings at all, behaved
exactly as though they had wings and could take flight. When it became
light, and those females with wings had flown, these females retreated
back down the nest entrances. Apparently they repeated this behavior
flight after flight, progressing from four wings to no wings at all.
The wings of female ants have lines of weakness along which they
normally break off after the female has gone on the mating flight. I
suspect that jostling in the crowded nest caused some wing breakage and
that the loss of one wing was enough to prevent flight. It was these
unfortunate females who slowly lost all their wings. I was unable to
determine the final fate of these females. It is unlikely any were
mated since a nest contained only one sex, and I did not observe males
near any tumulus containing females.
By 8 a.m. S^. (CL) pergandei females could be found at a second
study site: a USDA light trap at the Insects Affecting Man and Animals
Laboratory in Gainesville. If rainwater was standing on the trap roof,
large numbers of the males often were caught by their wings in the water
film, but few ever entered the trap. When rain did not fall for
several days, large flights took place. For example, rain occurred on
June 30, 1980, after a dry week. The light trap the following morning
contained 2,081 S_. (CL) pergandei alate females, 5 males and 83 dealated

94
females. Before I arrived, however, a number of these ants had already
been carried off by foraging Pheidole workers. Although held in the
laboratory several days, no further females shed their wings.
It seemed probable that large numbers of these females were mated,
particularity since rain afta a dry period would have coordinated a
number of colony flights. Examination of 20 dealated and 20 alate S_.
(_D.) pergandei females by Adrian Glover (USDA Fire Ant technician)
revealed that all the dealated females but only two of the alates were
mated. These data suggest that the 2,081 S_. (]D.) pergandei females
captured June 30, 1980, were mostly unmated. More information is needed
to resolve this question.
Twenty alate S. (£.) pergandei females in groups of five from the
light trap were placed on the ground and observed for 15 minutes. Within
seconds each female ran quickly into holes and under sticks and leaves
and took cover. When the cover was removed 15 minutes later, four
females were not found, three had begun to excavate, one had removed her
wings, and the remainder had simply remained hidden. Although this
behavior indicates females may found nests claustrally, attempts to induce
colony founding in the laboratory have not been successful.
In summary, S_. (D.) pergandei is the only subterranean Florida
Diplorhoptrum species which constructs nest structures at the soil surface.
It constructs crenelated tumuli from June through early September which
are utilized only for mating flights. These tumuli apparently allow
more sexuals to remain at the soil surface and offer a surface for flight
take-off. Nests produce only males or only females and each nest has
many flights during the summer. These flights occur before dawn, and
rain in the previous 24 hours is necessary for flight activity.

95
Section IV
The Role of S. (Diplorhoptrum) as Underground Predators
Preliminary Experiments
The large numbers of Diplorhoptrum found in the ground by Naves
trapping (Section II) suggested a further line of research: placing
target organisms in the traps to determine whether Diplorhoptrum would
prey upon them.
In February, 1976, a 15-trap wood plot and a 25-trap field plot
were set up and cabbage loopers were used as bait. Since this was
early in my Diplorhoptrum .research, I was unaware of the relative
inactivity of the ants at this time of year. The loopers were killed
by S^ (]).) carolinensis, but positive trap numbers remained at only
approximately 10 per cent.
This experiment was resumed in April, 1976, when three species of
Diplorhoptrum killed and fed upon the loopers. Sometimes, in the 48
hours the trap was down, the ants consumed the entire larva except for
the hollowed out head capsule left behind. The predatory Diplorhoptrum
species were primarily S_. (D_.) carol inensis but also S^. (]).) pergandei
and S_. (jD.) xenovenenum.
Predation on Fire Ant Females
In June, 1976, fire ant females were collected from local nests
and placed as bait in Naves traps. When the traps were recovered in
48 hours, seven of the 15 females had been killed and consumed by

96
:S. (D^.) carolinensis workers. In three of these vials the fire ant
queen had been consumed except for large pieces of chi tin. In the fourth
vial, not even the chitinous pieces of the female were left. Of 100
fire ant queens put out in traps August 8, 1980, eight were found dead.
Of these, three died of unknown causes, three were found with S_. (]D.)
carol inensis workers, one with S^. (D.) xenovenenum workers and one with
Pheidole floridana workers. Diplorhoptrum were also found in the traps
of eight live queens. In five of those, the Diplorhoptrum workers had
been killed and chewed into pieces by the fire ant queen.
Further experiments with fire ant females as bait and the role of
the Diplorhoptrum species in the control of this pest species are
underway.
Predation on Diaprepes abbreviatus larvae
The Sugar Care Rootstalk Borer Weevil, Diaprepes abbreviatus (L.),
threatens citrus in Florida. The larvae feed on citrus roots and
develop undergroud for two to three years. The weevil is presently
confined to quarantine areas surrounding Apopka and Davie, Florida.
In light of the above predation studies, and the fact that the
Diaprepes larva spends such a long period of its life underground, it
seemed logical to suspect that underground predators could have a
strong impact on Diaprepes populations.
Preliminary to testing this hypothesis, on July 25, 1979, 100 tuna-
baited Naves traps were placed at the tree base, drip line and row middles
of four citrus groves in the quarantine area which ranged from fully
managed, heavily insecticided groves to a grove untreated pesticidally
for 20 years. No Diplorhoptrum were found except in the pesticidally
untreated Forest City grove.

97
Further tests were conducted in the Forest City grove and in a
control (non-grove) area to determine Diplorhoptrum populations, but
results have been erratic: of 50 tuna-baited Naves traps placed in the
Forest City grove on August 23, 1979, only three were positive for ants
and none with Diplorhoptrum. Fifty traps in a non-grove control area
in woods (subsequently discovered to be old abandoned grove land) were
negative.
Of 50 traps placed in the Forest City grove on Sept. 18, 1979,
two were positve for S_. (_D.) carol inensis. In a new control area, 10
traps were positive for S_. (D_.) carol inensis, two for S_. (ID.) pergandei
and six for S_. (D_.) xenovenenum.
Results of baiting with tuna indicated that at least three Diplor
hoptrum species were present in low numbers in the Apopka area.
To ascertain the role of Diplorhoptrum in Diaprepes larvae control,
50 Naves traps containing Diaprepes larvae were placed in the Forest
City grove on Oct. 26, 1979. No control traps were used. No Diplor
hoptrum were captured with the larvae. A second set of traps (n=88)
with larvae were put down on May 13, 1980 and left for 72 hours. Fifteen
traps were put down in a non-grove area as a control. In the grove,
Pheidole spp. killed five larvae in the traps, but there was no detect
able predatory activity by Diplorhoptrum. In the control area, S.. (D_.)
xenovenenum and S_. (JD.) nickersoni each attacked and killed a larva.
These results were repeated, with Diplorhoptrum spp. again killing two
of 15 larvae in the control area on June 9 1980.
In summary, even in a grove untreated with pesticides for 20 years,
Diplorhoptrum populations were low. In control or non-grove areas
within the quarantine area Dipiorhoptrum populations were higher, and

98
were capable of killing and eating approximately 15% of the larvae
offered in the traps. Although these numbers may not seem significant,
if the Diplorhoptrum are capable of killing 15% of the Diaprepes in
traps in 72 hours, there is considerable chance that they could kill
a significant portion of the larvae over the two or three years the
larvae remain below ground.

SUMMARY
This study must be viewed as a preliminary effort in a neglected
area of myrmecology. No new species of Diplorhoptrum had been found in
North America since 1942. Yet a simple grid pattern of bait traps at
Gainesville, Florida, immediately captured three new species. A
fourth new species was discovered in randomized sod samples from Dade
County, Florida. Thus this group is poorly known in Florida.
The bait trap catches and ancillary studies seem to suggest
several other conclusions:
1. Bait trap sampling in the grid study varied between 53 and
75 per cent postiive for Diplorhoptrum during the summer months. All
trap locations were positive at least occasionally. The data are
consistent with information on generalized subterranean predators, which
have networks of exploratory tunnels rather than being uniformly present
in the soil. Ants that are strictly lestobiotic, always associated with
larger ants, could have been expected to show many gaps in their
distribution patterns. The data in this preliminary study suggest that
there are no distinct gaps in the subterranean spaces patrolled by
these ants.
2. Mosaic distribution patterns of the five Diplorhoptrum
species captured seem to be suggested by the data. These mosaic
patterns are similar to, if not entirely analogous with, the mosaic
patterns of arboreal ants in Ghana.
99

TOO
3. Diplorhoptrum species are able to kill and dismember in
sects much larger than themselves, like large Lepidoptera larvae,
fire ant queens, and Coleptera larva. This is probably due to the
potency of their venoms. These data again are consistent with wide
spread generalized predators, rather than with specialized predation as
exhibited by other cryptobiotic ants such as Strumigenys and Smithistruma.
The generalized morphological structure of Diplorhoptrum species is also
consistent with that of generalized predatory ants, as contrasted with
the highly specialized morphologies of the Dacetine ants.
4. Perhaps the most important finding that arises from this study
is the significant lack of general biological knowledge of these ants.
The ants were previously thought to be specialized, lestobiotic species
with sporadic distributions, yet they are now shown to be generalized,
widespread, abundant predators in Florida. An important question is
whether or not these or other similar ants have similar roles in other
areas of North America and of the world. If there is a network of sub
terranean ants on a worldwide or very widespread basis, then an important
component of ecosystems has been neglected.
The paucity of knowledge about Piplorhoptrum is nowhere better
seen than in the mating flight data. In spite of much observation,
S.. (_D.) pergandei mating flights were the only flights seen. The other
species apparently never construct tumuli. How their sexuals are brought
to the surface and what factors trigger their flights is unknown. It is
presumed that those species with dark colored sexuals with small eyes
and ocelli are diurnal flyers, while species with yellowish sexuals with
large eyes and ocelli are nocturnal flyers.

101
5. Questions this study has raised are the following:
a. What is the physiological and behavioral significance of
the venom chemistry of these ants?
b. Is it possible that there are negative correlations
between Diplorhoptrum populations and certain other ant populations
such as fire ants?
c. Is S_. (JL) molesta as widespread and common as it is reported
to be in the literature, or are these records partially based on
misdeterminations in this taxonomically difficult group?
d. Are Diplorhoptrum populations sometimes abundant enough to have
strong impact impact on the populations of pest organisms such as
imported fire ants, Sugar Cane Rootstalk Borer larvae, mole crickets,
and root knot nematodes?
e. Could Diplorhoptrum species from other areas of North America
or of the world be imported into Florida or the southeastern states
as biological control agents?

GLOSSARY
AlateHaving wings
Antennal clubThe last two segments at the tip of the antenna which,
in Solenopsis, are enlarged to form a club
BaseOf propodeum, the anterior dorsal surface of the propodeum
CrenelatedHaving towers, like a battlement
CryptobioticLife habits which involve remaining hidden, as under
ground, under debris or in other ways
DealatedWithout wings. In ants, females that have removed their
wings after the mating flight but before colony foundation
Dec!ivity'The inclined posterior surface of the propodeum
ExcisedCut out, posterior border of the head is concave
FuniculusSegmented part of the antenna extending from the end of
the scape to the tip of the antennal club
GasterThat portion of the abdomen, in Solenopsis, behind the post
petiole
InfuscationAn area darkened or tinged with brown or black
LestobioticA relationship in which a small ant species nests near a
larger ant species and robs the larger ants of their brood or
food supplies
Mayrian furrowsY-shaped mesonotal furrows in males of primitive ants
MyrmecophileAn animal that spends at least part of its life cycle
in an ant colony
Occipital borderThe posterior or hind margin of the head
PhragmosisThe head or posterior of the abdomen, often in the soldier
caste, is truncated to serve as a living plug for a nest entrance
Piligerous punctureA depression in the exoskeleton in which a hair
grows
102

103
PolymorphicHaving more than one form, said of ants with more than
one worker caste such as majors, minors or soldiers
PolygynousThe presence in one colony of two or more egg-laying
queens
ScapeThe rigid antennal section which arises from the head and
articulates with the funiculus
StratifiedNot random, selected on the basis of previously gathered
data
TumulusA mound of soil constructed at the entrance of an ant nest
and often characteristic of the species

APPENDIX
Table 1.
Preferred habitats and
nest sites of
S. (D.) molesta
State
Habitat
Nest Location
Reference
Arizona
Desert shrub community

Chew, 1977; Hunt, 1975
Arkansas
Cotton fields, many locales

Whitcomb et al., 1972;
Warren & Rouse, 1969
Colorado
5,600-6,500 ft, short grass
prairie, pinyon-cedar, oak
woods, in clay
Under rocks
Gregg, 1963
Idaho
S. molesta-Aqropyron repens
& L. niqer-Salsole pestifer
communities
Moist areas,
under flat rocks
Cole, 1933, 1936
Illinois
Dry or wet areas
Grass, mounds,
under stones,
debris beneath
bee combs
Amstutz, 1943
Frison, 1926
Louisiana
Pastures

Howard & Oliver, 1979
Michigan
High fields, old fields,
rocky beach

Talbot, 1953, 1965;
Gaige, 1914;
Gregg, 1972
Montana
Grasslands
Under rocks
Borchert & Anderson, 1973
N. Carolina
17 habitats of field
and forest
Under stones or
cover in ground
Carter, 1962a and
1962b
N. Dakota
Mostly grasslands
Under stones
Wheeler & Wheeler, 1963
New Jersey
Open sunny woods, clear
ings, woods borders

Wheeler, 1905a
New York
Open grass, gardens

Davis & Bequaert, 1922;
Fitch, 1856
Ohio
Woods and fields
Rotten wood,
under stones
Wesson & Wesson, 1940
S. Carolina
Pine plantation, oak pine,
hardwood hammock, old field
Logs, stumps,
soil
Van Pelt, 1966
Tennessee
Mostly dry grassy areas;
dense shade & open areas,
except mtn peaks, prefer
open, dry
Beneath stones,
wood
Cole, 1940; Dennis,
1938
Utah
Foothills, lower mtn slopes
Under fairly
large stones
Grundmann & Peterson,
1953; Cole, 1942
Virginia?
3,500-5,500 ft
In soil, under
rocks
Van Pelt, 1963
W. Virginia
Apple orchards
Compacted soil
in & near roads,
under roots
Jaynes & Marucci, 1947
104

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Wickham, H.F. 1892. Notes on some myrmecophi1ous Coleptera. Psyche
6:321-323.
Wickham, H.F. 1894. Further notes on Coleptera found with ants.
Psyche 7:79-81.
Wilson, E.O. 1964. The ants of the Florida Keys. Breviora 210:1-14.

114
Wilson, E.O. 1971. The insect societies. Belknap Press of Harvard
Univ. Press, Cambridge, Mass. 548 p.
Wilson, E.O. 1975. Enemy specification in the alarm-recruitment
system of an ant. Sci. 190:798-800.
Wing, M.W. 1951. A new genus and species of myrmecophilous Diapriidae
with taxonomic and biological notes on related forms. Trans. Roy.
Entomol. Soc. London 102:195-210.
Wolcott, G.N. 1948. The ants of Puerto Rico. J. of Agr. of Univ.
Puerto Rico 32:749-975.
Yensen, N.P. and W.H. Clark. 1977. A checklist of Idaho ants
(Hymenoptera:Formicidae). Pan Pacific Entomol. 53:181-187.
Young, J. and D.E. Howell. 1964. Ants of Oklahoma. Oklahoma Univ.
Exp. Sta. Mise. Pub. 71:1-42.

BIOGRAPHICAL SKETCH
Catherine R. Thompson was born November 21, 1952, in Boston,
Massachusetts. Her family moved to Cedar Falls, Iowa, where she
attended Malcolm Price Laboratory School. In June, 1971, she graduated
from Northern University High School in Cedar Falls.
She attended the University of Northern Iowa in Cedar Falls,
during the summers of 1971, 1972, 1973 and the fall of 1973. She
attended Cornell College during the remainder of 1971, 1972, 1973 and
part of 1974, graduating in June, 1974, with a B.A. in biology and
English.
In September, 1974, she entered graduate shcool in the Depart
ment of Entomology and Nematology at the University of Florida. She
received the M.S. degree in June, 1976, and commenced work'toward the
Doctor of Philosophy degree in entomology and a minor in botany at the
University of Florida.
115

I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
Dr. William F. Burn, Chairman
Professor of Entomology and Nematology
I certify that I have read this study and that in rcy opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation fo:~ the degree oF
Doctor of Philsophy.
/
/ i
yL-j 'C -.
Dij. Dana G.
Pfofessor of
7
I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scops and quality, as a dissertation for the degree of
Doctor of Philsophy.
.) J,
j /
'i
Dr. Reece I. Sailer
Graduate Research Professor of
Entomology and Nematology

This dissertation was submitted to the Graduate Faculty of the College
of Agriculture and to the Graduate Council, and was accepted as partial
fulfillment of the requirements for the degree of Doctor of Philosophy.
August, 1980
^ t
Dean,/'College of Agricwture
jLt'i
Dean, Graduate School



83
Summation Values
mo-50
[ED 51-200
HD 201 -599
U 600+
Figure 43. Five month (June-Oct., 1979) summation of the
distribution by trapping of (ID.) xenovenenum
in a long leaf pine-turkey oak woods at Gainesville,
Florida.


PLATE 3
Figure 9
Figure 1
Figure 1
Figure 1
Lateral view of worker of S_. (JD.) cortical is Fore!
(90X)
Head of the worker of S_. (j).) cortical is Forel
(200X)
. Petiole and postpetiole of worker of S^. (J).)
cortical is Forel (360X)
. Dorsal view of worker of S^. (J3.) cortical is Forel
(65X)


95
Section IV
The Role of S. (Diplorhoptrum) as Underground Predators
Preliminary Experiments
The large numbers of Diplorhoptrum found in the ground by Naves
trapping (Section II) suggested a further line of research: placing
target organisms in the traps to determine whether Diplorhoptrum would
prey upon them.
In February, 1976, a 15-trap wood plot and a 25-trap field plot
were set up and cabbage loopers were used as bait. Since this was
early in my Diplorhoptrum .research, I was unaware of the relative
inactivity of the ants at this time of year. The loopers were killed
by S^ (]).) carolinensis, but positive trap numbers remained at only
approximately 10 per cent.
This experiment was resumed in April, 1976, when three species of
Diplorhoptrum killed and fed upon the loopers. Sometimes, in the 48
hours the trap was down, the ants consumed the entire larva except for
the hollowed out head capsule left behind. The predatory Diplorhoptrum
species were primarily S_. (D_.) carol inensis but also S^. (]).) pergandei
and S_. (jD.) xenovenenum.
Predation on Fire Ant Females
In June, 1976, fire ant females were collected from local nests
and placed as bait in Naves traps. When the traps were recovered in
48 hours, seven of the 15 females had been killed and consumed by


72
S3
S.
(D.)
nensis
m
S.
(D.)
venenum
m
S.
(D.)
n.
sp.
S.
(D.)
Other genera
Figure 36.
Example of Naves trap samples
other species distribution in
turkey oak woods on June 24,
Florida.
of Diplorhoptrum and
a long leaf pine-
1979, at Gainesville,


98
were capable of killing and eating approximately 15% of the larvae
offered in the traps. Although these numbers may not seem significant,
if the Diplorhoptrum are capable of killing 15% of the Diaprepes in
traps in 72 hours, there is considerable chance that they could kill
a significant portion of the larvae over the two or three years the
larvae remain below ground.


11
Venom Chemistry
Venom chemistry and behavior associated with it have attracted
increasing interest and research in the past decade. Jones et al. (1979)
identified a new venomous constituent in the poison gland of S_. (D_.)
molesta and (D.) texana. The chemical, 2-hexyl-5-pentyl-pyrrolidine,
is the first known 2,5-dialkyl pyrrolidine from a natural source.
More recently, a new alkaloid, (5Z,8E)-3-heptyl-5-methyl pyrrolizidine
has been identified (Jones et al., in press) in S^. (D.) xenovenenum
n.sp. denoted as a species near (j).) tennesseensis. Wilson (1975)
studied Pheidole dentata Mayr and found a chemical alarm-recruitment
system in the minor caste which recruits the majors. It is a chemical
which specifically recruits the majors to ants of the genus Solenopsis.
Holldobler (1973) reported that S_. (D.) fugax (Latreille) (European
species) has a recruitment pheromone produced by the Dufour gland and a
repellent substance produced by the poison gland. The repellent pre
vents brood-keeping ants from defending their own larvae against the
Diplorhoptrum. Blum and Jones (1980) found that the S^. (D_.) fugax
substance repelled 18 species of ants. The secretion of one gland
would stop Lasius flavus McCook from using a nest entrance for almost
an hour. The main component was trans-2-butyl-5-heptylpyrrolidine, a
dialkyl-pyrrolidine which is evidently an integral part of S.. (D.)
fugax raiding strategy.


FIGURE PAGE
39 Five month (June-Oct., 1979) summation of the
distribution by trapping of (j).) carol inensis
in an open field at Gainesville, Florida 79
40 Five month (June-Oct., 1979) summation of the
distribution by trapping of jS. (j).) abdita in an open
field at Gainesville, Florida 80
41 Five month (June-Oct., 1979) summation of the
distribution by trapping of S. (]D.) carol inensis in
a long leaf pine-turkey oak woods at Gainesville,
Florida 81
42 Five month (June-Oct., 1979) summation of the
distribution by trapping of S^. (|).) abdita in a long
leaf pine-turkey oak woods at Gainesville, Florida. ... 82
43 Five month (June-Oct., 1979) summation of the
distribution by trapping of S^. (j).) xenovenenum
in a long leaf pine-turkey oak woods at Gainesville,
Florida 83
44 Number of months each trap site in an open field at
Gainesville, Florida, was positive for three species of
Diplorhoptrum (June 1979-June 1980) 84
45Number of months each trap site in a long leaf pine-turkey
oak woods at Gainesville, Florida, was positive for
three species of Diplorhoptrum (June 1979-June 1980). . 85
46Correlation of S^. (D.) pergandei mating flights with
times of sunrise in Gainesville, Florida 91
ix


77
S_. [D_.) carolinensis mosaic patterns were the most complex. In the
field there appear to be four colonies with wide-ranging territories
(Fig. 39). Foraging areas of two additional colonies appear to be only
partially present in the grid. In the woods site, there is probably
one large colony and a second smaller colony with a much smaller
foraging area around Meter 82 (Fig. 41).
The colony and foraging patterns of S^. (I).) abdita and S^. (D_.)
xenovenenum are less complex. There appear to be 4 colonies of S_. (J).)
abdita in the field grid and only probably two colonies in the woods,
with perhaps an incipient colony in Meters 84-85 (Figs. 40,42). S^. (ID.)
xenovenenum occupied only one meter in the field site, but appeared to
have three colonies (Fig. 43) and part of the foraging territory of a
fourth in the woods site.
The data in Figs. 39-43 are subject to more than one interpretation
and boundaries could easily be drawn somewhat differently. In addition,
the true correlation of colony numbers and territories indicated by
trapping data with those actually present in the field remains unknown.
It is hoped that the Naves trap method may eventually be found to
indicate true Diplorhoptrum territories and colony numbers.
In the field site S^. (D.) carol inensis is the dominant species while
S. (£.) pergandei is an occasional dominant, or to use Majer's (1972)
terminology sensu strictu, a sub-dominant, i.e., a species capable at
times of becoming a dominant. Yet many more S^. (J3.) pergandei queens
were found during field excavation and in light traps than were S. (J).)
carolinensis. This would be consistent with a species which does not
expend energy in large queens and mating flights, but whose small queens
may mate mostly in the nest and remain in the nest to produce large,


75
Ant activity dropped sharply between October and November and began
to increase the following year between April and May. Having observed
the sharp cessation of activity in the fall, I suspected soil tempera
tures might be a factor and began to monitor them. On April 15 the
field soil temperatures taken at 14 cm were 15.3, 16.3 and 17.0 C.
The wood soil temperatures were 16.0, 16.3 and 17.0 C. By May 16 a
distinct increase was evident: field soil temperatures were 23.3, 23.3
and 24.0 C while wood soil temperatures were 21.0, 21.5 and 21.50 c.
These data indicate that soil temperature may be a major factor in
seasonal Diplorhoptrum activity patterns.
The major question posed by these collection data is how many nests
and of what species are present? Estimates of colony numbers and
territorial sizes can be made based on the following assumptions:
1. Few ant species build one-chambered nests, and all known
Solenopsis build multi-chambered nests. It can be assumed Diplor
hoptrum have multi-chambered nests.
2. All known Solenopsis have discrete nests. Large populations
covering large areas without discrete nests probably do not occur in
Diplorhoptrum species. Diplorhoptrum are here assumed to have discrete
nests and foraging areas which do not extensively overlap.
3. From the appearance of S_. (D.) pergandei tumuli clusters, which
are constructed following rain (Fig. 33), the network of chambers and
tunnels below may be assumed to be diffuse. The nest probably occupies
a region comparable to the size of the cluster on the surface and not
more than 1 or 2 meters in area.
4. Each ant colony controls available food sources over as wide
an area as possible. Dominant species may be assumed to control large


42
7. Solenopsis (Diplorhoptrum) picta Emery
Solenopsis tenuis Ma.yr, 1886. Zool-Bot. Gesell. Wien, Verh.
36:262. Nec. S_. tenuis Mayr 1877.
Solenopsis picta Emery, 1895. Zool Jahrb., Abt. f. System. 8:278.
Solenopsis picta var. moerens Wheeler, 1915. Bull.Amer. Mus.
Natur. Hist. 34:393.
Solenopsis (Diplorhoptrum) picta. Creighton 1950. Bull. Mus.
Comp. Zool. 104:237-238.
Type locality: Florida
Types: Museo Civico di Storia Naturale "Giacomo Doria," Genoa, Italy
Range: Gulf States from Florida west to Texas
Diagnosis:
An arboreal species living in tree twigs. It has a strong
mesopropodeal impression, and the promesonotum and propodeum are
both strongly convex in profile. Petiolar node set forward from the
petiolar-postpetiolar juncture. Hairs are sparse, and of various
lengths, and do not arise from punctures. The body shining. Color
black, including appendages. A color variant occurs which is paler,
often reddish brown.
Di scussion:
This species is common throughout Florida and the southeastern
states, but is limited to habitats with dead wood and twigs in which to
nest. It is a polygynous species, easily reared in the laboratory.
I have a colony captured two years ago, July 23, 1979, which
produced sexuals this past May. The sexuals are not attracted to light
traps. Van Pelt found this species most commonly in bayhead areas (1958).


35
Florida, (2-) molesta is reported from Rockdale, in Dade County,
(Nielsson et al., 1971) where it was tending Aphis coreopsidis
(Thomas), but no further information on the biology is given. Van Pelt
(1958) reports this species from Wei aka Reserve and observed the ants
closely. He noted that what he was tentatively calling molesta did
not match specimens he had seen. Van Pelt was one of the few authors
(Mitchell and Pierce, 1912; Ross et al., 1971; Huddleston and Fluker,
1968 were others) who qualified their identifications and noted the
existing taxonomic confusion.
At this time I have found no specimens of S_. (]).) molesta in
Florida, nor have I seen any in other Florida collections. Van Pelt's
specimens are S. (D.) carolinensis.


107
Cook, T.W. 1953. The ants of California. Pacific Books, Palo Alto.
462 p.
Creighton, W.S. 1930. The new world species of the genus Solenopsis
(Hymenop. Formicidae). Proc. Amer. Acad. Arts Sci. 66:39-151.
Creighton, W.S. 1950. The ants of North America. Bull. Mus. Comp.
Zool. 104:1-585.
Davis, W.T. and J. Bequaert. 1922. An annotated list of the ants of
Staten Island and Long Island, N.Y. Bull. Brooklyn Entomol. Soc.
17:1-25.
Dennis, C.A. 1938. The distribution of ant species in Tennessee with
reference to ecological factors. Ann. Entomol. Soc. Amer. 31:
267-308.
Eckert, J.E. and A. Mall is. 1937. Ants and their control in California
California Agr. Exp. Sta. Circ. 342:1-39.
Emery, C. 1895. Beitrage zur kenntniss der nordamerikanischen
Ameisenfauna. Zool. Jahrb., Abt. f. System. 8:257-360.
Esser, R.P. 1973. A four.minute lactophenol fixation method for
nematodes. Plant Dis. Rep. 57:1045-1046.
Ettershank, G. 1966. A generic revision of the world myrmicinae re
lated to Solenopsis and Pheidoloqeton (Hymenoptera:Formicidae).
Australian J. Zool. 14:73-171.
Fall, H.C. 1928. Alaudes. Pan-Pacific Entomol. 4:145-150.
Felt, E.P. 1916. Thirtieth report of the state entomologist. New
York State Mus. Bull. 180:10, 68-69.
Fitch, A. 1856. First and second report on the noxious, beneficial
and other insects of the state of New York. 336 p.
Forbes, S.A. 1896. Insect injuries to the seed and root of Indian
corn. Illinois Agr. Exp. Sta. Bull. 44:209-296.
Forbes, S.A. 1920. A monograph of insect injuries to Indian corn.
Eighteenth Rept. State Entomol. Illinois. 149 p.
Forel, A. 1901. Variets Myrmcologiques. Ann. Soc. Entomol. Belg.
45:334-382.
Frison, T.H. 1926. Contributions to the knowledge of the interrela
tions of the bumblebees of Illinois with their animate environment.
Ann. Entomol. Soc. Amer. 19:203-235.
Gaige, F.M. 1914. Results of the Mershon Expedition to the Charity
Islands, Lake Huron. The Formicidae of Charity Island. Occasional
papers of Mus. of Zool., Univ. of Michigan 5:1-29.


PAGE
Types 29
Discussion 29
2. Solenopsis (Diplorhoptrum) carolinensis
Forel. 31
Diagnosis 31
Discussion 31
3. Solenopsis (Diplorhoptrum) cortical is Forel. 33
Diagnosis 33
Discussion 33
4. Solenopsis (Diplorhoptrum) mol esta (Say) ... 34
Diagnosis 34
Discussion 34
5. Solenopsis (Diplorhoptrum) nickersoni n. sp. 36
Diagnosis 36
Description 36
Worker 36
Female 37
Male 37
Types 37
Discussion 38
6. Solenopsis (Diplorhoptrum) pergandei Forel . 40
Diagnosis 40
Discussion 40
7. Solenopsis (Diplorhoptrum) pieta Emery .... 42
Diagnosis 42
Discussion 42
8. Solenopsis (Diplorhoptrum) reinerti n.sp.. . 43
Diagnosis 43
Description 43
Worker 43
Female 44
Male 45
Types 45
Discussion 45
9. Solenopsis (Diplorhoptrum) tennesseensis
M. R. Smith 46
Diagnosis 46
Discussion 46
10. Solenopsis (Diplorhoptrum) texana Emery. ... 47
Diagnosis 47
Discussion. . 47
11. Solenopsis (Diplorhoptrum) truncorum Forel . 48
Diagnosis 48
Discussion 48
12. Solenopsis (Diplorhoptrum) xenovenenum n.sp. 49
Diagnosis 49
Description 49
Worker 49
Female 50
Male 51
Types 52
Discussion 52
v


108
Gotwald, W.H. 1969. Comparative morphological studies of the ants,
with particular reference to the mouthparts (Hymenoptera:Formicidae).
Cornell Univ. Agr. Exp. Sta. Memoir 408:1-150.
Gregg, R.E. 1963. The ants of Colorado. Univ. of Colorado Press,
Boulder. 792 p.
Gregg, R.E. 1972. The northward distribution of ants in North
America. Can. Entomol. 104:1073-1091.
Gross, H.R. and W.T. Spink. 1969. Responses of striped earwigs fol
lowing applications of Heptachlor and Mi rex, and predator-prey
relationships between imported fire ants and striped earwigs. J.
Econ. Entomol. 62:686-689.
Grundmann, A.W. and B.V. Peterson. 1953. House infesting ants in Salt
Lake City, Utah. J. Kansas Entomol. Soc. 26:59-60.
Hayes, W.P. 1920. Solenopsis molesta Say (Hym.): A biological study.
Kansas Agr. Exp. Sta. Tech. Bull. 7:1-55.
Hayes, W.P. 1925. A preliminary list of the ants of Kansas (Hymenoptera,
Formicidae). Entomol. News 36:39-43.
Headlee, T.J. and J.W. McColloch. 1913. The chinch bug. Kansas Agr.
Exp. Sta. Bull. 191:287-353.
Herrick, G.W. 1921. Insects injurious to the household and annoying
to man. Macmillan Co., New York. 470 p.
Holldobler, B. 1973. Chemische Strategie beim Nahrungserwerb der
Diebsameise (Solenopsis fugax Latr.) und der Pharoameise
(Monomorium pharoanis L.). Oecoloqia (Berl.) 11:371-380.
Howard, F.W. and A.D. Oliver. 1979. Field observations of ants
(Hymenoptera:Formicidae) associated with red imported fire ants,
Solenopsis invicta Burn, in Louisiana pastures. J. Georgia
Entomol. Soc. 14:159-163.
Huddleston, E.W. and S.S. Fluker. 1968. Distribution of ant species
of Hawaii. Proc., Hawaiian Entomol. Soc. 20:45-69.
Hung, A.C. 1974. Ants recovered from refuse pile of the Pyramid Ant
Conomyrma insana (Buckley) (Hymenoptera:Formicidae). Ann. Entomol.
Soc. Amer. 67:522-523.
Hunt, J.H. 1975. A checklist of the ants of Arizona. J. Arizona
Acad. Sci. 10:20-23.
Hunter, W.D. and W.D. Pierce. 1912. Mexican cotton boll weevil. USDA
Bur. Entomol. Bull. 144:1-188.


45
Male: Unknown
Types:
Holotype a worker taken by core sod sampling in Dade County,
Florida, on July 29, 1974, by J. A. Reinert. Paratypes are numerous
workers and females collected by J. A. Re inert. Other paratypes are
one female (and workers later reared by her) collected on June 23,
1979, in Gainesville, Florida, by C. R. Thompson.
The holotype and several paratypes will be deposited at the
Museum of Comparative Zoology. Paratypes will also be deposited in
the Florida State Collection of Arthropods, Gainesville, Florida.
This species is named in honor of J. A. Reinert who was the first
to capture this cryptic new species.
Pi scussion:
Very little is known about this new species. J. C. Trager
(Department of Entomology and Nematology, University of Florida) found
sexuals and workers of this species beneath a stone at the edge of woods
on June 29, 1980. He collected reinerti males at a blacklight at
5:45 a.m. on June 26, 1980.
The workers of this species are so similar to those of carolinensis
that identifications remain questionable if only workers are available.
The dark brown to black female, however, is so different from the
large-eyed, reddish-yellow female of carolinensis that it is clear that
two taxa are involved. Although presently known from only two Florida
localities, the species may prove to be common and widespread.


88
Section III
The Mating Flights of S. (D.) pergandei
Solenopsis (Diplorhoptrum) pergandei is the largest species of the
subgenus that occurs in Florida. It is also the only species that
constructs a visible structure (tumulus) surrounding its nest opening
at the soil surface. From June through early September, within 24 hours
after a rain, S_. (JD.) pergandei constructs unique, crenelated tumuli
for early morning mating flights.
Tumuli Construction
The tumuli are constructed with passages wide enough for several
females to pass (ca. 6 mm ) and with walls twice or more their body
height (ca. 5-10 mm). I have seen some tumuli 16 cm in diameter. One
benefit of these passages is probably an increase in the number of
sexuals that can remain at the soil surface in preparation for a flight
while still remaining under the protection of the workers. On June 23,
1979, at 4:20 a.m., I observed sexuals massed at the surface even
though this flight did not occur until nearly 6 a.m.
A second function of these tumuli is probably to present a flight
take-off surface for the departing sexual forms, although I have
observed the heavy females climbing up grass blades near the nest.
On morning when flights did not occur, the ants constructed tumuli
of two additional types. These I have called "closed" tumuli and
"digging-cut" tumuli. The closed tumuli were sometimes constructed on


17
and a Strumigenys species. In areas infested with S_. invicta, the
fire ants chewed at the cap holes until they were large enough to gain
entrance to the bait. Their chewing habit cost me considerable time
in the making of new caps.
Unfortunately, the Dispobeakers have been discontinued by the
manufacturer. Traps have now been made from plastic, cap-attached
vials made by Bio-Rad Company. These traps will be utilized in South
America studies in the near future but are still in the experimental
stage.
Local Distribution Study
Studies of small area distribution of Diplorhoptrum species were
undertaken utilizing stratified sampling. A 5 x 10 square meter grid
was laid out in a open field at the Gainesville Airport. The field is
mowed twice a year, maintaining grasses and occasional young turkey
oaks (Quercus laevis Walt.) below 3-4 ft. The area is designated for
use only as an emergency runway. A second 5x10 square meter grid was
laid out in a long leaf pine (Pinus palustris Mi 11.)--turkey oak woods
bordering the northeast side of the open field.
Biweekly (June 1979-July 1979) and then bimonthly (Aug. 1979-
June 1980) Naves traps were loaded with tunafish and placed one in
the center of each square meter of the grids. The traps were placed
at a depth of 14 cm for 24 hours. At the end of 24 hours the traps were
taken up. Traps with ants were quickly placed in snap-top vials for
later indentification. The square meter was rebaited with another trap.
Following 24 hours, the traps were again taken up, positive traps


33
3. Solenopsis (Diplorhoptrum) cortical is Forel
Solenopsis corticalis Forel, 1904. Ann. Soc. Entomol. Belg.
48:172.
Type locality: Cuba
Types: Museum d Histoire Naturelle, Geneva, Switzerland. None in this
country
Range: West Indies (Wheeler, 1913; Wolcott, 1948) and southern Florida
Diagnosis:
Small arboreal species. Head is rectangular and the eyes are
large in comparison with other species of the group. Petiole has
anterioventral tooth. Hairs are rather sparse, of uneven lengths and
do not arise from punctures. The integument is highly shining. Color
is yellow or light brownish-yellow, usually without trace of infuscation.
Discussion:
This is one of the two known arboreal Diplorhoptrum in Florida,
but appears to be much rarer than pi eta and is yellowish whereas pi eta
is black to dark reddish-brown.
Prior to this study, S_. (CL) corticalis had not been reported from
Florida. A series of this species was taken near Manalapan, a coastal
town south of Palm Beach in November, 1945, by Dr. William F. Burn.
It was found in branches of red mangrove (Rhizophora mangle L.). It was
subsequently rediscovered by Dr. J. C. Nickerson in the same habitat
in May, 1980, on Park Key. This species is polygynous and is probably
nocturnal, as no foragers were seen in the daylight. Specimens from the
Manalapan series have been compared with West Indian material at the
Museum of Comparative Zoology by Dr. William F. Burn.


73
3 S. (D.) carol inensis
S. (D.) abdita n. sp.
ffiS. (D.) xennvenenum n. sp.
S. (£.) pergandei
S. (D.) nickersoni n. sp.£
10
T / / / ////// / /
/ / / / / / / / / / / /
/ / / / / / / / / '
/ / / / / / / / /
/ /
L.
! / /
/
/
/
JJASONDJFMAMJ
1979 Month 1980
Figure 37. Diplorhoptrum species captured by Naves trap in
an open field at Gainesville, Florida, from June
1979-June 1980.


no
Majer, J.D. 1972. Ant mosaic in Ghana cocoa farms. Bull. Entomol.
Res. 62:151-160.
Mallis, A. 1941. A list of the ants of California with notes on
their habits and distribution. Bull. Southern California Acad.
Sci. 40:61-100.
Mann, W.M. 1911a, Notes on the guests of some Californian ants.
Psyche 18:27-31.
Mann, W.M. 1911b. On some northwestern ants and their guests.
Psyche 18:102-109.
Markin, G.P., J. O'Neal, and H.L. Collins. 1974. Effects of Mirex on
the general ant fauna of a treated area in Louisiana. Environ
mental Entomol. 3:895-898.
Mayr, G. 1855. Zoologisch-Botanische Gesellscheft. Wien, Verhandl.
5:449-450.
Mayr, G. 1886. Die formiciden der Vereinigten Staaten von Nordamerika.
Zoologisch-Botanische Gesel1schaft. Wien, Verhandl. 36:419-464.
Mitchell, J.D. and W.D. Pierce. 1912. The ants of Victoria County,
Texas. Proc. Entomol. Soc. Wash. 14:67-76.
McColloch, J.W. and W.P. Hayes. 1916. A preliminary report on the
life economy of Solenopsis molesta Say. J. Econ. Entomol. 9:
23-38.
Nielsson, R.J., A.P. Bhatkar, and H.A. Denmark. 1971. A preliminary
list of the ants associated with aphids in Florida. Florida
Entomol. 54:245-248.
O'Neal, J. 1974. Predatory behavior exhibited by three species of
ants on the imported fire ants: Solenopsis invicta Burn and
Solenopsis richteri Forel. Ann. Entomol. Soc. Amer. 67:1.
Pierce, W.D. 1912. The insect enemies of the cotton boll weevil.
USDA Bur. Entomol. Bull. 100.
Rees, D.M. and A.W. Grundmann. 1940. A preliminary list of the ants
of Utah. Bull. Univ. of Utah 31:1-12.
Robbins, W.W. 1910. An introduction to the study of the ants of
northern Colorado. Univ. Colorado Studies 7:215-222.
Ross, H.H., G.L. Rotramel, and W.E. Laberge. 1971. A synopsis of
common and economic Illinois ants, with keys to the genera
(Hymenoptera, Formicidae). Illinois Natur. Hist. Surv. Biol.
Notes 71:1-22.


LIST OF FIGURES
FIGURE PAGE
1 Lateral view of worker of S.. (J).) abdita n.sp. (65X). . 54
2 Head of the worker of S^. (JD.) abdita n.sp. (120X) .... 54
3 Petiole and postpetiole of worker of S. (D.) abdita
n.sp. (340X) 54
4 Dorsal view of worker of S.. (D.) abdita n.sp. (50X) ... 54
5 Lateral view of worker of S. (D.) carolinensis Forel
(60X) 56
6 Head of worker of S^. (£.) carol inensis Forel (130X) ... 56
7 Petiole and postpetiole of worker of S. (D.) carolinensis
Forel (290X) 56
8 Dorsal view of worker of S. (D.) carolinensis Forel
(56X) 56
9 Lateral view of worker of S^. (Dj cortical is Forel (90X). 58
10 Head of the worker of S^. (jD.) cortical is Forel (200X) . 58
11 Petiole and postpetiole of worker of S. (D.) cortical is
Forel (360X) 58
12 Dorsal view of worker of S. (DO cortical is Forel (65X) 58
13 Lateral view of worker of ,S. (£.) nickersoni n.sp. (75X). 60
14 Head of the worker of S. (j).) nickersoni n.sp. (120X) . 60
15 Petiole and postpetiole of worker of S. (D.) nickersoni
n. sp. (420X) 60
16 Dorsal view of worker of S_. (£.) nickersoni n.sp. (65X) 60
17 Lateral view of worker of S^. (£.) pergandei Forel (79X) 62
18 Head of the worker of S^. (CL) pergandei Forel (98X) ... 62
vi i


101
5. Questions this study has raised are the following:
a. What is the physiological and behavioral significance of
the venom chemistry of these ants?
b. Is it possible that there are negative correlations
between Diplorhoptrum populations and certain other ant populations
such as fire ants?
c. Is S_. (JL) molesta as widespread and common as it is reported
to be in the literature, or are these records partially based on
misdeterminations in this taxonomically difficult group?
d. Are Diplorhoptrum populations sometimes abundant enough to have
strong impact impact on the populations of pest organisms such as
imported fire ants, Sugar Cane Rootstalk Borer larvae, mole crickets,
and root knot nematodes?
e. Could Diplorhoptrum species from other areas of North America
or of the world be imported into Florida or the southeastern states
as biological control agents?


68


26
profile; males and females dark brown to black; wings heavily
and entirely infuscated with dark brown xenovenenum n. sp.
7a) Dorsal surfaces of head with moderately numerous hairs nearly
entirely of the same short length (Figs. 6, 26) 8
b) Dorsal surfaces with sparser hairs, these distinctly uneven
in length (Fig. 10) 9
8a) Rear of head and anterior portion of gaster lightly to moderately
infuscated with brown; eyes with 3 or 4 facets; females yellow
ish to light yellowish brown; female eyes very large, eye
index 41 carol inensis Forel
b) Head and gaster without infuscation; uniformly pale yellow,
some specimens nearly whitish; eyes with 2 facets; females dark
brown to black; female eyes small, eye index 33. . reinerti n.sp.
9a) Comparatively large size; body length 1.58 mm; head length
0.491 0.004 mm; head and gaster usually weakly infuscated;
subterranean *texana Emery
b) Small size, body length 1.34 mm; head length 0.363 0.003 mm;
entirely light brownish yellow without trace of infuscation
on any areas; arboreal cortical is Forel
*S. (_D.) tennesseensis and S^. (jD.) texana were not found in Florida in
the present study, and previous records seem doubtful. It is
possible that these species will eventually be found in Florida.


TABLE OF CONTENTS
PAGE
ACKNOWLEDGMENTS 111
LIST OF FIGURES vii
ABSTRACT x
INTRODUCTION 1
REVIEW OF LITERATURE 3
Taxonomy 3
Distribution 4
Economic Importance 5
Biology and Ecology 8
Venom Chemistry 11
MATERIALS AND METHODS 12
Taxonomy 12
Lactophenol Fixation 13
Scanning Electron Micrography 14
Field Studies 15
Collecting Techniques 15
Naves Traps 16
Local Distribution Study 17
Use of Light Trap Collections 18
Laboratory Studies 18
Colony Nest Materials 18
Feeding 20
Queen Colony Founding 20
RESULTS 22
Section I: A Taxonomic Review of the S..
(Diplorhoptrum) of Florida 22
Introduction 22
Key to S. (Diplorhoptrum) Species of Florida 24
1. Solenopsis (Diplorhoptrum) abdita n.sp.. . 27
Diagnosis 27
Description 27
Worker 27
Female 28
Male 29
iv


I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
Dr. William F. Burn, Chairman
Professor of Entomology and Nematology
I certify that I have read this study and that in rcy opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation fo:~ the degree oF
Doctor of Philsophy.
/
/ i
yL-j 'C -.
Dij. Dana G.
Pfofessor of
7
I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scops and quality, as a dissertation for the degree of
Doctor of Philsophy.
.) J,
j /
'i
Dr. Reece I. Sailer
Graduate Research Professor of
Entomology and Nematology



PAGE 1

SOLENOPSIS ( DIPLORHOPTRUM ) (HYMENOPTERA: FORMICIDAE) OF FLORIDA By Catherine R. Thompson A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1980

PAGE 2

Copyright 1980 by Catherine Rose Thompson

PAGE 3

ACKNOWLEDGEMENTS I wish to thank my committee chairman, Dr. William F. Buren, for his help and encouragement on all phases of this study, and Drs. C.S. Lofgren, D.6. Griffin, S.H. Kerr and R.I. Sailer for their assistance in preparing this dissertation. I am grateful to Greg Erdos for instruction on SEM techniques, to Dr. J.L. Nation for colony laboratory space and to P.T. Carlysle for scanning electron micrographs of S^. (fJ.) picta and S_. (J3.) cortical is I appreciate Dave Gowan's time for photographs of S_. (D_. ) pergandei tumul i Many thanks are also due to Dr. D.P. Wojcik for access to his collections and literature files. I am also grateful to Dr. J.C. Nickerson for his specimens of S^. (D_. ) cortical is and his continuous encouragement and advice. iii

PAGE 4

TABLE OF CONTENTS PAGE ACKNOWLEDGMENTS iii LIST OF FIGURES vii ABSTRACT x INTRODUCTION 1 REVIEW OF LITERATURE 3 Taxonomy 3 Distribution 4 Economic Importance 5 Biology and Ecology 8 Venom Chemistry 11 MATERIALS AND METHODS 12 Taxonomy 12 Lactophenol Fixation 13 Scanning Electron Micrography 14 Field Studies 15 Collecting Techniques 15 Naves Traps ..." 16 Local Distribution Study 17 Use of Light Trap Collections 18 Laboratory Studies 18 Colony Nest Materials . 18 Feeding 20 Queen Colony Founding 20 RESULTS 22 Section I. A Taxonomic Review of the S. ( Diplorhoptrum ) of Florida 22 Introduction 22 Key to S. ( Diplorhoptrum ) Species of Florida. . 24 Solenopsis ( Diplorhoptrum ) abdita n.sp.. 27 Diagnosis 27 Description 27 Worker 27 Female 28 Male 29 iv

PAGE 5

PAGE Types 29 Discussion 29 2. Solenopsis ( Diplorhoptrum ) carol inensis Forel. 31 Diagnosis 31 Discussion 31 3. Solenopsis ( Diplorhoptrum ) cortical is Forel. 33 Diagnosis 33 Discussion 33 4. Solenopsis ( Diplorhoptrum ) molesta (Say) ... 34 Diagnosis 34 Discussion 34 5. Solenopsis ( Diplorhoptrum ) nickersoni n. sp. 36 Diagnosis 36 Description 36 Worker 36 Female 37 Male 37 Types 37 Discussion 38 6. Solenopsis ( Diplorhoptrum ) pergandei Forel 40 Diagnosis 40 Discussion 40 7. Solenopsis ( Diplorhoptrum ) picta Emery .... 42 Diagnosis 42 Discussion 42 8. Solenopsis ( Diplorhoptrum ) reinerti n.sp.. 43 Diagnosis 43 Description 43 Worker 43 Female 44 Male 45 Types 45 Discussion 45 9. Solenopsis ( Diplorhoptrum ) tennesseensis M. R. Smith 46 Diagnosis 46 Discussion 46 10. Solenopsis ( Diplorhoptrum ) texana Emery. ... 47 Diagnosis 47 Discussion. 47 11. Solenopsis ( Diplorhoptrum ) truncorum Forel 48 Diagnosis 48 Discussion 48 12. Solenopsis ( Diplorhoptrum ) xenovenenum n.sp. 49 Diagnosis 49 Description 49 Worker 49 Female 50 Male 51 Types 52 Discussion 52 v

PAGE 6

PAGE Section II. Subterranean Distribution of Diplorhoptrum Species 71 Section III. The Mating Flights of S_. ( D_ ) pergandei ... 88 Tumuli Construction 88 Flight Factors 89 Flight and Postflight Activities 90 Section IV. The Role of S_. ( Diplorhoptrum ) as Underground Predators 95 Preliminary Experiments 95 Predation on Fire Ant females 95 Predation on Diaprepes abbreviatus Larvae 96 SUMMARY 99 GLOSSARY 102 APPENDIX 104 LITERATURE CITED 105 BIOGRAPHICAL SKETCH 115 vi

PAGE 7

LIST OF FIGURES FIGURE PAGE 1 Lateral view of worker of S. (D.) abdita n.sp. (65X). 54 2 Head of the worker of S. ( D ) abdita n.sp. (120X) .... 54 3 Petiole and postpetiole of worker of S. ( D ) abdita n.sp. (340X) 54 4 Dorsal view of worker of S. (D.) abdita n.sp. (50X) ... 54 5 Lateral view of worker of S. (D.) carol inensis Forel (60X) 7.7. 56 6 Head of worker of S. ( D ) carol inensis Forel (130X) ... 56 7 Petiole and postpetiole of worker of S. (D.) carol inensis Forel (290X) .-. 56 8 Dorsal view of worker of S. (D.) carol inensis Forel (56X) .56 9 Lateral view of worker of S. (D.) cortical is Forel (90X). 58 10 Head of the worker of S. (D. ) cortical is Forel (200X) 58 11 Petiole and postpetiole of worker of S. (D.) corticalis Forel (360X) ~ .~ 58 12 Dorsal view of worker of S. (D.) corticalis Forel (65X) 58 13 Lateral view of worker of S. ( D ) nickersoni n.sp. (75X). 60 14 Head of the worker of S. (D. ) nickersoni n.sp. (120X) 60 15 Petiole and postpetiole of worker of S. (D.) nickersoni n. sp. (420X) ~ ,~ m 60 16 Dorsal view of worker of S. ( D ) nickersoni n.sp. (65X) 60 17 Lateral view of worker of S. ( D ) pergandei Forel (79X) 62 18 Head of the worker of S. (D.) pergandei Forel (98X) ... 62 vii

PAGE 8

FIGURE PAGE 19 Petiole and postpetiole of worker of S. (D.) pergandei Forel (165X) ~ 62 20 Dorsal view of worker of S. (D ) pergandei Forel (75X). 62 21 Lateral view of worker of S. (D.) picta Emery (70X) ... 64 22 Head of the worker of S. ( D ) picta Emery (140X) .... 64 23 Petiole and postpetiole of worker of S. (D_. ) picta Emery (378X) 64 24 Dorsal view of worker of j>. ( D. ) picta Emery (70X) ... 64 25 Lateral view of worker of S. (D ) reinerti n.sp. (90X). 66 26 Head of the worker of S. (D. ) reinerti n.sp. (140X) ... 66 27 Petiole and postpetiole of worker of S. (D ) reinerti n.sp. (460X) . 66 28 Dorsal view of worker of S. (D.) reinerti n.sp. (50X) 66 29 Lateral view of worker of S. (D.) xenovene num n.sp. (83X) 7.7. 68 30 Head of the worker of S. (D. ) xenovenenum n.sp. (150X). 68 31 Petiole and postpetiole of worker of S. ( D ) xenovenenum n.sp. (460X) 68 32 Dorsal view of worker of S. (D. ) xenovenenum n.sp. (84X). 68 33 Cluster of mating flight tumuli of S. (D.) pergan dei Fore l 70 34 Mating flight tumulus of S. ( D ) pergandei Forel 70 35 Mating flight tumulus of S. (D ) pergandei Forel 70 36 Example of Naves trap samples of Diplorhoptrum and other species distribution in a long leaf pine-turkey oak woods on June 24, 1979, at Gainesville, Florida 72 37 Diplorhoptrum species captured by Naves trap in an open field at Gainesville, Florida, from June 1979-June 1980 73 38 Diplorhoptrum species captured by Naves trap in a long leaf pine-turkey oak woods at Gainesville, Florida, from June 1979-June 1980 74 vi ii

PAGE 9

FIGURE PAGE 39 Five month (June-Oct. 1979) summation of the distribution by trapping of {D. ) carol inensis in an open field at Gainesville, Florida 79 40 Five month (June-Oct., 1979) summation of the distribution by trapping of S.. ( D ) abdita in an open field at Gainesville, Florida 80 41 Five month (June-Oct., 1979) summation of the distribution by trapping of S. (D. ) carol inensis in a long leaf pine-turkey oak woods at Gainesville, Florida 81 42 Five month (June-Oct., 1979) summation of the distribution by trapping of S^. (D. ) abdita in a long leaf pine-turkey oak woods at Gainesville, Florida. ... 82 43 Five month (June-Oct., 1979) summation of the distribution by trapping of S_. (D. ) xenovenenum in a long leaf pine-turkey oak woods at Gainesville, Florida 83 44 Number of months each trap site in an open field at Gainesville, Florida, was positive for three species of Diplorhoptrum (June 1979-June 1980) 84 45 Number of months each trap site in a long leaf pine-turkey oak woods at Gainesville, Florida, was positive for three species of Diplorhoptrum (June 1979-June 1980). 85 46 Correlation of S. ( D ) pergandei mating flights with times of sunrise in Gainesville, Florida 91 ix

PAGE 10

Abstract of Dissertation Presented to the Graduate Council of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy SOLENOPSIS ( DIPLORHOPTRUM ) (HYMENOPTERA:FORMICIDAE) OF FLORIDA By Catherine R. Thompson August, 1980 Chairman: Dr. William F. Buren Major Department: Entomology and Nematology Prior to this study, six species of the subgenus Solenopsis ( Diplorhoptrum ) were reported from Florida. In the present study, four new species were found in the state. New information on S. ( Diplorhoptrum ) prevalence, mating flights and role as predators was obtained. Review of the literature on Diplorhoptrum indicated that these were thief-ants, present in relatively small numbers in the soil, and usually in close association with nests of larger ants. Use of unique, baited traps revealed Diplorhoptrum in unexpectedly large numbers with a wide distribution in the soil. The ants were present in all but extremely hydric habitats in Florida. In this study, eight species of Diplorhoptrum were found: six subterranean species, and two arboreal species. Four species previously reported from Florida were not found. Examination of available voucher specimens showed these to be misidentif ied. It seems possible that authentic specimens of some of these species will eventually be found x

PAGE 11

in Florida. Independent studies have shown that the venom of one of the new species contains (5Z,8E)-3-heptyl-5-methyl pyrrol izidine, the first recorded occurrence of this substance in any animal or plant. In subterranean studies, 50 traps each in an open field and a long leaf pine-turkey oak woods were baited each month for a year. Five Diplorhoptrum species came to the traps, three of which were new. The dominant species in both habitats was S. (D ) carol inensis while S. (D.) pergandei was found only in the woods site, and the remaining species were present in both habitats. The nest locations and foraging territories were mapped and found to have mosaic patterns. Ant activity nearly stopped between October and November and did not reach high levels again until the following May. Soil temperature is probably a major factor in this activity pattern. May soil temperatures were five to seven degrees higher than those in April. The only Diplorhoptrum species which constructed nest structures at the soil surface was S. ( D ) pergandei These structures were crenelated tumuli constructed for mating flights. The tumuli apparently allow more sexual s to remain near the soil surface and also provide a surface for flight takeoff. Mating flights for this species took place one half hour before dawn from June through August, mostly when there had been rain in the previous 24 hours. The predatory activities of Diplorhoptrum were studied. They readily killed and consumed newly mated imported fire ant queens, Solenopsis mvicta Buren. Several Diplorhoptrum species were also found to kill and eat the larvae of the Sugar Cane Rootstalk Borer, Diaprepes abbreviatus (L. ). The indications are that Diplorhoptrum species may be important subterranean predators and should be further investigated for their potential as biological control agents. xi

PAGE 12

INTRODUCTION There are approximately 8,000 known taxa of ants in the world, and the habits exhibited are extremely diverse (Wilson, 1971). Three principal ecological types may be said to exist in the Formicidae. These are: I. Arboreal species, ants which nest in trees and forage for food or obtain their food in trees or non-aborescent plants, II. Terrestrial ants which nest in the soil and forage for food mostly on the soil surface, and III. Subterranean or cryptobiotic ants, ants that nest and forage underground or beneath debris seldom coming to the soil surface. Species may, of course, occupy more than one of these habitats. Cryptobiotic ants are interesting academically because they often are highly modified structurally Ants of the generally cryptobiotic tribes Dacetini and Basicerotini as well as other aberrant genera, have been described and figured in many papers, of which Brown (1962), Brown and Kempf (1967), Brown (1974) and Brown (1977) are examples. The highly modified structures of these ants probably adapt them for specialized predation on soil arthropods and are fortuitously useful in taxonomic studies. Subterranean ants are generally thought to be lestobiotic. Solenopsis ( Diplorhoptrum ) as well as related subterranean genera such as Oligomyrmex Carebara Carebarella are also more generalized in structure. They have few specialized features which makes them 1

PAGE 13

2 difficult to study taxonomically. Whitcomb et al (1972) and Buren et al. (1977) suggested that this group of genera and species might be much more important as generalized subterranean predators than had been previously suspected, and that their role in lestobiosis might be secondary. These studies were undertaken as an investigation into the abundance, ecology, taxonomy, and predatory importance of these ants in Florida. The data will revise thinking on the importance of these predators in the subterranean ecosystem. The study also helps to emphasize the need for similar studies on a world-wide basis.

PAGE 14

REVIEW OF LITERATURE Taxonomy The genus Solenopsis is essentially cosmopolitan and is found in all but the coldest parts of the world. The genus was divided by Creighton (1950) into three subgenera: Solenopsis Euopthalma and Diplorhoptrum The painful stings inflicted by members of the Solenopsis ( Solenopsis ) group have attracted public attention as the red Imported Fire Ant Solenopsis invicta Buren continues to spread in the southern and southwestern U.S. While not endearing themselves to the general public, the genus Solenopsis is also no favorite of ant taxonomists. Creighton (1950) grumbled "The student of North American ants may count himself fortunate that so few species of this difficult genus occur in our latitudes" (p. 226). The worker caste in Solenopsis has undergone extreme convergence, making identification to species difficult. Unfortunately most of this convergence has occurred in Diplorhoptrum The taxonomic postion of Diplorhoptrum is subject to discussion. Ettershank, in his revision of the Solenopsini (1966), synonymized Diplorhoptrum under Solenopsis Baroni-Urbani (1968) resurrected the group and gave it full generic status. Unfortunately he based his determination on the male genitalia of the common European species, S. (D. ) fugax (Latreille), without knowledge of the Neartic and Neotropical fauna. Although Creighton suspected that male and female 3

PAGE 15

4 morphology may indeed be the only reliable source of characters on which to base Diplorhoptrum taxonomy, the fact remains that at present few of the males are known. For this reason American myrmecologists have been reluctant to accept Baroni-Urbani 's work (pers. comm., W. F. Buren). Retaining Diplorhoptrum as a subgenus may be acceptable simply for convenience: as a group Diplorhoptrum are usually small, monomorphic species as opposed to the larger, polymorphic, free-living fire ants (MacConnell et al 1976). All S. ( Diplorhoptrum ) species have the 2nd and 3rd joints of the funiculus distinctly broader than long, whereas in ( Solenopsis ) and ( Euopthalma ) species these joints are longer than broad. To search the literature on Diplorhoptrum one must be aware that the species most frequently published upon, S. (D.) molesta, is also found under five synonyms: Myrmica molesta Say, Myrmica minuta Say, Myrmica ex i qua Buckley, Solenopsis debilis Mayr, and Solenopsis molesta (Say). There has been an unfortunate tendency to identify every small yellow thief ant as S. (D. ) molesta The problem is compounded by the fact that S^. ( D_ ) molesta is the only economic pest in the Diplorhoptrum group. As a result much of the literature concerning S^. ( D ) molesta may be based on mi sdetermi nations. Distribution Creigton (1950) listed 12 taxa of Diplorhoptrum for North America. The most recent compilation (Smith, 1979) also contains 12 taxa: 10 from Creighton's original list, one species renamed, and one placed in synonomy. At least one Diplorhoptrum species has been reported

PAGE 16

5 from each of the contiguous 48 states with S_. (D_. ) mo Testa (Say), the most widespread species, reported from 30 states. The species reported from Florida are S_. (D_ ) molesta (Say), S_. (fJ. ) pergandei Forel S_. ( D. ) pi eta Emery, S_. ( D_. ) tennesseensis Smith, S_. (D ) texana Emery, and S_. (rj. ) truncorum Forel Economic Importance Although not as notorious as their fire ant relatives, Diplorhoptrum or thief ants as they are commonly called, contains one species, Solenopsis ( Diplorhoptrum ) molesta (Say), which is a pest in fields and dwellings. As a result of this pest status, and erroneous identifications, most of the literature deals with this species. Although Creighton (1950) reported it to be distributed only in the central and eastern states, it has subsequently been reported from eight of the 11 western states (Appendix). S. (D_. ) molesta is best known as a economic pest of sorghum. The ant is known as the "kafir ant" in Kansas (Bryson, 1941; Hayes, 1925) where it has been called the single most damaging pest of planted sorghum (Burkhardt, 1959). The ants diminish sorghum stands by feeding on germinating sorghum seed (Young and Howell, 1964). They have destroyed thousands of acres of sorghum necessitating one to six replantings and then not always with a resultant full stand (McColloch and Hayes, 1916). Srivastava and Bryson (1956) found that tilling the soil, planting early, and using various insecticides or insecticidefungicides prior to planting helped avoid damage. All of the compounds tested were effective, while the ants damaged 50% of the check seeds. McColloch and Hayes (1916) found that only late plantings were

PAGE 17

6 damaged. Early planting, along with seed treatment, fall plowing, and surface planting have essentially eliminated the kafir ant problem. S_. (D. ) molesta has been reported to eat out the interiors of corn kernels, and in New York is known as the "little yellow ant" (Fitch, 1856) and the "yellow field ant" (Felt, 1916). There are reports of strawberries (Fitch, 1920) and blackberries (Webster, 1893) damaged by S. (D. ) molesta This ant may also indirectly damage crops through its habit of tending various species of aphids (Landis, 1967; Smith & Morrison, 1916; Webster, 1893). It attacked the cocoons of the Japanese beetle parasite Tiphia and killed 20% in the laboratory (White, 1940). Smith (1965) reported S. ( D ) molesta as a host of a poultry tapeworm. S.. (D. ) molesta is one of only two of our native ant species which invades homes (Wheeler, 1910). Herrick (1921) reported on the "little fiery ant" which invaded kitchens. While Forbes (1896, 1920) and Fitch (1856) stated that this ant had a sweet tooth Back (1937) said that it fed "almost entirely" on greasy substances. It is possible that a number of Diplorhoptrum species may be involved. S. (D. ) molesta validiuscula Emery is a common pest in California homes where it lives in crevices around sinks and feeds on greases, meats, and cheese (Mai lis, 1941). Among the more curious of S. ( D. ) molesta dietary preferences was an insect collection (Fitch, 1856) while an artist complained that S. ( D. ) molesta was eating his paints (Webster, 1893). Nearly as many reports in the literature point to S. (D.) molesta as a valuable predator as malign this species as an economic pest. Brooks (1906) observed S. (D. ) molesta in large numbers feeding on grape curculio, Craponius inaequalis (Say), larvae. The ant killed

PAGE 18

7 walnut curculio larvae, Conotrachelus juglandis Lee, in young black walnuts on the ground (Brooks, 1910). It attacked boll weevil larvae, Anthomomis grandis Hubner (Hunter & Pierce, 1912; Hunter & Hinds, 1904; Pierce, 1912) was observed carrying chinch bug eggs, Blissus leucopterus (Say), (Headlee & McColloch, 1913) and eggs and small larvae of the cabbage maggot Phorbia braassicae Bouche (Schoene, 1916). In studies on the striped earwig, Labidura riparia (Pallas), spraying heptachlor to control S. ( D. ) molesta appeared to increase earwig populations. S. (D. ) molesta was subsequently observed feeding on earwig eggs in experimental field plots (Gross & Spink, 1969). S_. (D. ) molesta seems to be particularly important as a predator on codling moth, Carpocapsa pomonella Linn., larvae and pupae (Brooks & Blakeslee, 1915; Jaynes & Marucci, 1947). The workers cut small characteristic holes in the cocoons, accounting for 2.5 to 64.2% of all attacked cocoons. Those near the colony site were killed by the ants in 2-5 minutes. S. (D. ) molesta is listed as a predator in Arkansas cotton fields (Whitcomb et al 1972; Whitcomb & Bell, 1964). S. ( D ) molesta has been found living with S. invicta and richteri Forel where it was seen eating eggs and early larval instars of S. invicta (Collins & Markin, 1971; O'Neal, 1974). Interestingly, S. (D. ) molesta was unaffected by the Mirex bait used to kill S. invicta in Louisiana (Markin et al., 1974). Ayre (1963) fed S. ( D. ) molesta colonies both live and dead insects of a number of species. The ants consumed 39 of 49 live insects and 53 of 54 dead insects. They also ate eggs of the weevil Sitona scissifrons Say. Ayre concluded that S. ( D ) molesta "may be as effective a predator as those species that capture larger insects," but "limited in their choice of food because they are small" (p. 715).

PAGE 19

8 The role of other Diplorhoptrum species as predators is not nearly as clear. Published reports are few. S^. (D.) texana was observed attacking boll weevil larvae in Texas, Louisiana, and Mississippi (Hunter & Pierce, 1912). S_. ( D ) molesta validiuscula Emery was often found attacking codling moth larvae under experimental tree bands in West Virginia apple orchards (Jenne, 1909). Biology and Ecology Because Diplorhoptrum species are still in considerable taxonomic flux, there are few published reports relating to the biology and ecology of the species. The bulk of information concerns microhabitat and ecosystem distributions. In Table 1 (Appendix), data on nesting locations of S. (D. ) molesta is presented. Although this species seems able to establish colonies in most types of habitats, on the microhabitat level it displays a distinct preference for cover, particularly stones. What is known concerning the biology of Diplorhoptrum species consists of observations dispersed through the general literature on ants with almost no exhaustive studies. For example, in at least one western state (Utah) S. (D. ) molesta validiuscula is considered a dominant Diplorhoptrum species, is 1.3 mm long, lives under stones, bark, and logs (Cole, 1942), and has been observed feeding on chicks, rats, and mice (Eckert & Mall is, 1937). Hayes (1 920) has conducted the only biological study of S. (D ) molesta His thorough study determined life tables for the brood, field colony size, queen egg production, flight information, and methods of laboratory colony maintenance. One of the most interesting habits of S. ( D ) molesta as well as other Diplorhoptrum species, is lestobiosis. This ant has been found

PAGE 20

9 living beside or with 33 different species of ants of four subfamilies (Cook, 1953; Hayes, 1920; King, 1896, 1901a & b; Mai lis, 1941; Mann, 1911a; and Wheeler, 1901). S. (D ) molesta will also live amicably with the termite Reticul itermes flavipes (Kollar) in the laboratory (Smythe & Coppel 1973). The data on Diplorhoptrum species which are freeliving or lestobiotic are lacking, spotty, or contradictory. While Kennedy (1938) found four nests of S. ( D_. ) texana all lestobiotic, Wheeler and Wheeler (1963) made 81 collections of which 53 were independent nests. They were unable to determine if the ants were S^. ( D_. ) molesta or S^. (D. ) molesta val idiuscula They found that the independent nests had h" dia. chambers as much as 5" below the soil surface, but mostly in the upper 2V. As Wheeler (1901) pointed out, however, there could be long connecting galleries between these species and their suspected host galleries or no relationship at all. Diplorhoptrum are themselves hosts of a number of guests. Wheeler discovered the first guest, reported only as a Hymenopteran (Brues, 1903). Fall (1920) found a new species of blind beetle Maudes alternata Fall in S. ( D ) molesta nests. King (1895, 1897) observed a mite on larvae which attached midway between the thorax and abdomen and a Staphylinid of the tribe Aleocharini Schwarz (1890a & b, 1896) found Coleoptera of the genera Lithocharis and Myrmecochara with (D_. ) molesta but believed the former to be an accidental guest. Wickham found the latter beetle with the ants, first calling it Gyrophaena sp. but later correcting the name (1892, 1894) to Myrmecochara crinita Casey. He felt this species to be a true myrmecophile along with Atheta exilissima Casey. Wing (1951) found a number of wasp guests of the genera Buresopria and Auxopaedeutes and Loxotropa cal ifornica Ashmead.

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10 S. (D. ) molesta appears to have few natural enemies, although research lags in this area. Beal (1911, 1912) found that a flicker, Colaptes auratus L. subsp., and the kingbird or bee martin, Tyrannus tyrannus (L.) feed on S. (D ) molesta No less than 39 species of birds were observed feeding on a mating flight of S. (D. ) molesta (Judd, "•901). Diplorhoptrum probably have a number of ant enemies, but only two are reported: Hung (1974) found that 10% (or 80) of the ants' heads in the garbage pile of a Conomyrma nest were those of S. (D. ) molesta Buren et al (1977) suggest false phragmosis evolved by Pheidole lamia Wheeler serves as a defensive tactic against subterranean ants, mainly Diplorhoptrum It is fortunate that two astute observers have published their observations on the mating flights of S. (D ) molesta In Kansas, Hayes (1925) observed a flight at 5 p.m. on July 27, 1920, which continued until dusk, and a flight July 5, 1921. Both were preceded by heavy rain. He noted that mating occurred in the air, that females outnumbered males (unusual in ants), and that males mated more than once. Farther north in Canada, late August flights occurred (Macnamara, 1945; Wheeler, 1916) and Macnamara observed a dense evening swarm, 3-4 ft in diam. and at its lowest point about 3 ft off the ground. He saw that the swarm was sluggish and noticed, most importantly, that the females were carrying workers on their bodies. Wing (1951) reported that W. L. Brown found approximately 20% of the S. (D.) mojesta females in a Philadelphia flight had one or rarely two workers attached to their legs.

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11 Venom Chemistry Venom chemistry and behavior associated with it have attracted increasing interest and research in the past decade. Jones et al (1979) identified a new venomous constituent in the poison gland of S. (D. ) molesta and S_. (D. ) texana The chemical, 2-hexyl -5-pentyl -pyrrol idine, is the first known 2,5-dialkyl pyrrolidine from a natural source. More recently, a new alkaloid, (5Z,8E)-3-heptyl -5-methyl pyrrol izidine has been identified (Jones et al., in press) in S. (D. ) xenovenenum n.sp. denoted as a species near S. ( fJ ) tennesseensis Wilson (1975) studied Pheidole dentata Mayr and found a chemical alarm-recruitment system in the minor caste which recruits the majors. It is a chemical which specifically recruits the majors to ants of the genus Solenopsis Holldobler (1973) reported that S. (D. ) fugax (Latreille) (European species) has a recruitment pheromone produced by the Dufour gland and a repellent substance produced by the poison gland. The repellent prevents brood-keeping ants from defending their own larvae against the Diplorhoptrum Blum and Jones (1980) found that the S. (D.) fugax substance repelled 18 species of ants. The secretion of one gland would stop Lasius flavus McCook from using a nest entrance for almost an hour. The main component was trans-2-butyl -5-heptyl pyrrol idine, a dial kyl -pyrrol idine which is evidently an integral part of S. (D. ) fugax raiding strategy.

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MATERIALS AND METHODS Taxonomy Because the largest Florida S. ( Diplorhoptrum ) worker is only 1.8 mm long, it is imperative that anyone wishing to study this group have at their disposal a microscope with a minimum of 40 diameters of magnification. The Wild microscope used for this study was also equipped with an ocular micrometer. Traditional measurement techniques were utilized and specimens were compared with types at the U.S. Natural History Museum in Washington, D.C., and the Museum of Comparative Zoology at Harvard University, Cambridge, Mass. Measurements of specimens and indexes calculated were as follows: 1. Head width: greatest width of the head in full face view. 2. Head length: greatest length of the head in full face view, but excluding the mandibles. 3. Head index: Head width x 100 Head length 4. Head depth: measured on line running through the eye and perpendicular to line running from just above mandibular insertion to point where neck meets thorax. 5. Thoracic length: greatest length of thorax in lateral view. 6. Scape length: middle of antennal socket to tip of scape. 7. Scape index: Scape length x 100 Head length 8. Funiculus length: tip of scape to tip of funicular club. 12

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13 9. Club length: length of last 2 antennal segments which form the typical club. 10. Body length: total length of specimen from mandibles to tip of the gaster. This measurement cannot be made as accurately as the others. Specimens were so rarely in a natural position on the pins that only a rough estimate was made of total body lengths. 11. Eye length: greatest length of the eye. 12. Eye index: Eye length x 100 Head length Specimens studied were obtained from as many locations as possible in Florida. Series collected by D. P. Wojcik (USDA, Gainesville, Florida) and by A. F. Van Pelt (collections in the Florida State Collection of Arthropods, Gainesville, Florida) and Dr. William F. Buren (Dept. of Entomology and Nematology, Univ. of Florida, Gainesville, Florida) were studied. Lactophenol Fixation A novel method for taxonomic study of ants was use of slidemounted specimens prepared by a four minute lactophenol fixation process (Esser, 1973) initially developed for nematode studies. This rapid procedure cleared specimens and allowed particularly detailed study of pubescence. 1. The ants were removed from alcohol and placed in water in a watch glass set inside a petri dish on a hot plate. 2. The specimens were heated to 370C and lactophenol added until the watch glass was full.

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14 3. The specimens were heated an additional two minutes then were cooled 10 minutes. 4. A ring of "zut" (Thorn, 1935), a sealant used to mount helminths, is placed on a slide. The ring is built up enough to avoid crushing the specimens (and requires practice and extra specimens). The ants, in some lactophenol solution, are placed in the ring and a cover slip placed over the ants and the zut. Having a number of ants per slide ensured that at least one would be positioned correctly for any structure studied. Scanning Electron Micrography Diplorhoptrum workers are so small that use of the usual black carbon contact cement was nearly impossible. Split-second timing was needed, otherwise the cement dried or the specimen disappeared under the cement. These problems were overcome by the use of double-stick white labels. The ants were arranged on the label and pushed into the adhesive. But a problem developed with charging (a process which results in bright light bouncing off the specimen and obscuring structure), even though the specimens had been double-gold-coated at three minutes per coat with a break between coatings to dissipate heat. To alleviate charging, the ants were placed on the sticky labels and spots of carbon glue were placed near the specimens and smeared into contact with the tarsi or under parts of the body. In this way conduction was increased and charging reduced.

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15 Field Studies Collecting Techniques Unlike many terrestrial ant species, Diplorhoptrum have few surface indications of nest location, with the exception of (D_. ) pergandei mating flight tumuli (Figure 29). Diplorhoptrum are nocturnal and, even at night, forage little above ground except in moist areas. As a result, conventional methods were not as effective in locating and collecting these ants; however, the following techniques were utilized with some success: 1. Lifting bark from bases of trees and from rotten logs. Species most frequently obtained were S^. ( D_. ) pergandei and S.. ( D. ) carol inensis 2. Searching for unnatural soil disturbances such as slight mounds and color changes indicating excavations, or for parts of dead insects grouped in one place. 3. Overturning stones, logs, and other soil cover and tearing apart rotten logs. 4. Searching shovelfuls of soil for foragers, particularly in moist areas and along the edges of tree roots. Although this method would seem time consuming and the finding of any ants a matter of chance, it was one of the most effective. One morning's work and nearly 200 shovelfuls produced one S. (D. ) carolinensis queen and workers and an additional sample of workers; a second morning's work produced one i. ( D. ) pergandei queen and colony. In a third area one half hour of work produced two S. (D. ) carolinensis queens and col ones.

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These collections were in different habitats, the first two areas were xeric while the third area was hydric. Naves Traps Naves traps (unpublished technique) were baited with honey agar (Bhatkar and Whitcomb, 197C), cabbage loopers, Diaprepes beetle larvae, Fire Ant queens (S. invicta ), or most often tunafish. The Naves trap is made by modifying a two ml sidetabbed Dispobeaker (Scientific Products) as follows: A teasing needle is heated and used to melt 0.5-0.9 mm diam. holes in the cap and bottom of the beaker. Three holes are placed in the cap top, six around the sides of the cap and three in the bottom of the trap body. All attempts to further standardize hole size by wiring a soldering iron with 1/16 inch copper wire failed; the wire would not hold enough heat to melt the plastic. Acrylic red yarn tied around the trap under the side tabs served as a marker and means of pulling the trap from the ground. A narrow bladed trowel (5 cm at greatest width) was used to bury the traps with their bases at a depth of 14 cm. It was found that less than 10 cm depths resulted in traps filled with fine sand which sifted through the trap tops in dry soils. Depths of 18 cm or more made trap recovery and replacement of the soil difficult. The 14 cm depth was chosen as an average and employed throughout trapping experiments as an experimental constant. As a note of caution, even the small holes of these traps did not exclude a number of other ant species: Pheidole metal! escens Emery, Brachymyrmex depilis Emery, Pheidole dentata Mayr, and P. floridana Emery. Other less frequent species were Ponera pennsyl vanica Buckley

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17 and a Strumigenys species. In areas infested with S_. invicta the fire ants chewed at the cap holes until they were large enough to gain entrance to the bait. Their chewing habit cost me considerable time in the making of new caps. Unfortunately, the Dispobeakers have been discontinued by the manufacturer. Traps have now been made from plastic, cap-attached vials made by Bio-Rad Company. These traps will be utilized in South America studies in the near future but are still in the experimental stage. Local Distribution Study Studies of small area distribution of Diplorhoptrum species were undertaken utilizing stratified sampling. A 5 x 10 square meter grid was laid out in a open field at the Gainesville Airport. The field is mowed twice a year, maintaining grasses and occasional young turkey oaks ( Quercus laevis Walt. ) below 3-4 ft. The area is designated for use only as an emergency runway. A second 5x10 square meter grid was laid out in a long leaf pine ( Pinus palustris Mi 1 1 )--turkey oak woods bordering the northeast side of the open field. Biweekly (June 1979-July 1979) and then bimonthly (Aug. 1979June 1980) Naves traps were loaded with tunafish and placed one in the center of each square meter of the grids. The traps were placed at a depth of 14 cm for 24 hours. At the end of 24 hours the traps were taken up. Traps with ants were quickly placed in snap-top vials for later identification. The square meter was rebaited with another trap. Following 24 hours, the traps were again taken up, positive traps

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18 put in vials, and red marker yarn placed in the soil to mark the bait station until it was rebaited. Use of Light Trap Collections During May through August, Diplorhoptrum males and females of S. (D_. ) pergandei (D_. ) carolinensis and rarely S_. (D_. ) reinerti are attracted to light traps. Larger collections of (D_. ) carol inensis can be made with a light trap and a white sheet than with a conventional, walk-in light trap. The reason for this is unknown, but possibly a different quality of ultraviolet light is reflected by the sheet, and thus attracts this species. Laboratory Studies Colony Nest Materials Maintaining Diplorhoptrum colonies in the laboratory is extremely difficult. Their small size and hypogaeic habits make them highly vulnerable to desiccation. Workers of colonies in open laboratory pans at 80% relative humidity die within 24 hours. If a colony is presented with a moist chamber within an open laboratory pan, the workers which forage outside the chamber will die in the open pan before they find their way back to the colony. The colony dies by slow loss of foraging workers. Florida Diplorhoptrum species seem to need humidity levels of nearly 100%, in contrast to S. (D.) molesta and other Diplorhoptrum species such as the unidentified Peruvian species in Dr. Ed Wilson's laboratory at Harvard University. This species is kept in a plastic box open to the air. Lower humidity requirements apparently allow

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19 ( D. ) molesta and (D ) texana to forage above ground during the day. S^. ( D_. ) texana was observed in a late morning expedition to food in a car trunk (July, 1980) at Clinton, Iowa (pers. comm., Dr. W. F. Buren) while I have taken $. ( D_ ) texana at honey baits in full sun (June, 1980) at Cedar Falls, Iowa. Two materials often used to maintain ant nest humidity are plaster of paris and Castone When colonies were placed in petri dishes with floors of either compound, workers began to go into convulsions within a few hours, then died. An entire _S. ( D_. ) carol inensis colony died overnight June 3, 1980, while a S. ( D. ) pergandei colony displayed similar symptoms the following day. The queen died two days after exposure to these compounds, or possibly because of shock due to colony loss. Neither species queen showed convulsive symptoms. Colony nest humidity was finally maintained by 1) moistened cotton floors, or 2) by using "aged" plaster of paris covering only one fourth of the nest floor. The aged plaster was in old petri dish nests which had been used and repeatedly washed in hot, soapy water. The small size of the Diplorhoptrum workers allows them to escape from any kind of petri dish. Talc and Fluon could not be used because of the high humidity levels. When colonies were sealed in with artist's clay, the workers gnawed 0.82 mm holes through the clay and escaped. In colonies sealed with vaseline, many workers died overnight, apparently from fumes given off by this material. Finally the vegetable fat Crisco was tried. The ants refused to cross the greasy barrier. Crisco was subsequently placed around the inside rims of petri dishes effectively preventing ant escapes.

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20 When an Iowa S^. (D_. ) molesta colony was placed in a Crisco barriered nest, however, the workers began to eat the Crisco — something none of the Florida species had done! The colony is presently housed in a glass jar with a screw-top lid. Feeding Colonies offered a selection of foods including 1:1 honey-water, butter, raw hamburger, peanut butter, honey-agar, oil -packed tunafish, fire ant diet (used by USDA, Fire Ant Laboratory, Gainesville, Florida), and mealworms. S^. (D_. ) carol inensis fed upon the honey-agar and tunafish, but largely ignored the other foods. They backed off hurriedly from peanut butter. Mealworm larvae were killed, but did not appear to be fed upon. Although S_. (JJ. ) pi eta and S^. (D_. ) reinerti accepted fire ant diet and honey-agar readily, colonies of S^. (D_.) pergandei were reluctant feeders on all offered foods. Fire ant larvae were also offered to this species but were refused, even when the larvae were punctured so that haemolymph exuded. Colonies of this species could not be maintained for more than a few months. Queen Colony Founding Young, newly mated females obtained from light traps were initially placed in compartmented plastic boxes. Each compartment had a moistened plaster of pan's floor and sides painted with Fluon The high humidity allowed the queens to walk over the Fluon however, and they congregated in groups. Of 36 S^. (D_. ) carol inensis 45 S_. ( D_. ) pergandei and two S_. (D.. ) reinerti females, eight S^. (D_. ) carol inensis no S.. (D_. ) pergandei and both (D_. ) reinerti queens reared brood to

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21 the worker stage. No S_. (D_. ) pergandei queen was able to found a colony. Some queens laid eggs and had larvae, but died before workers were reared. Other materials and methods were then tried: 1. Glass tubes with moistened cotton. 2. Aged plaster of pan's bottomed vials with soil above the plaster and black paper for cover. 3. Cores of grass sod placed in vials, allowing excavation and a more natural environment. 4. Placement in queenless laboratory colonies. Methods 1-3 were unsuccessful. Method 4--addition of queens to queenless colonies--ended inconclusively. The females were initially seized by the legs and antennae, but subsequently were released and allowed to stand over the brood. Of 12 females added, six had died before the colony had to be left unattended for two weeks. The colony died during that time. In summary, no satisfactory method was found for inducing queen colony foundation in S^. (D_. ) pergandei Presenting young queens with brood or callows of their species will probably prove to be the most useful method. Queens of S_. ( JJ ) carol inensis found colonies readily in plaster of pan's cups if they are allowed to remain together in groups. Queens of S_. ( D_ ) reinerti founded colonies easily alone. It was, in fact, the unexpected yellow workers reared by these black queens that first convinced me that they were a new species.

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RESULTS Section I A Taxonomic Review of the S. (Diplorhoptrum) of Florida Introduction No taxonomic progress has been made in the Solenopsis ( Diplorhoptrum ) group for a number of years. The most recent species to be described was S. (£.) longiceps by M. R. Smith in 1942. This species name was subsequently found to be preoccupied by Solenopsis longiceps Forel and was changed to S. (D. ) tennesseensis M. R. Smith in 1951. The most recent taxonomic key for the group is that by Creighton (1950) in which he tried to define the group and synonymized several names. Because of taxonomic and identification difficulties, most workers have been lumping any Diplorhoptrum specimen under S. ( D ) molesta. This species, in fact, is supposed to occur in Florida, but I have not collected it anywhere in the state. The situation is not improved by the fact that all of Say's types, including those of S. ( D. ) mol esta (Say), have been lost. When a small, 100-meter square area in Gainesville was sampled and three new species were frequently recovered, it was very apparent that taxonomic work was needed. This study will help to prevent the "bandwagon" effect, which has gone on for many years, of labeling any Diplorhoptrum specimen molesta It will fill the gap left by Van Pelt (1947) who purposely omitted the group from his Florida key because of their uncertain taxonomy. 22

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23 The four new species found during this study have the proposed names of ( D. ) abdita n.sp., S_. (ID.) nickersoni n.sp., S.. (D_.) reinerti" n.sp. and S^. ( D_. ) xenovenenum n.sp. (Names proposed here in quotation marks are not to be considered validly or effectively published for nomenclatural purposes.)

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24 Key to S. (Diplorhoptrum) Species of Florida la) Mesopropodeal constriction strong (Fig. 21); promesonotum and propodeum, in profile, strongly convex; petiolar node placed somewhat anterior to the petiolar-postpetiolar juncture (Fig. 23) so that the petiole has a distinct slender posterior portion; color uniformly dark brown or black including the appendages; an arboreal ant found nesting in twigs and small branches of various trees picta Emery b) Lacking above combination of characters; mesopropodeal constriction not as strong; promesonotum and propodeum never both strongly convex; petiolar node placed near the petiolar-postpetiolar juncture; color usually pale yellow, or if dark, then the appendages are pale; subterranean (except for one rare yellow arboreal species) 2 2a) Head, thorax, and gaster dark brown with pale brown or pale yellow appendages; eyes of medium size for this group of species; with 2, occasionally 3 facets; subterranean. nickersoni n.sp. b) Usually entirely pale yellow to somewhat darker yellow; one species ( carol inensis ) with moderate infuscations of brown on head and gaster 3 3a) Dense pilosity on head and usually on promesonotum arising from large, obvious punctures; eyes small or weakly pigmented or both 4 b) Pilosity not arising from large, obvious punctures and not noticeably dense; eyes larger or at least pigmented, the facets surrounded by a black matrix 7

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25 4a) Thorax in profile straight above; base and declivity of propodeum distinguishable; head narrow and elongate, head index 79; punctures on head over entire surface, no median streak free of punctures and hairs tennesseensis M. R. Smith b) Head proportionately not as narrow; head in some species with distinct median streak free of punctures and hairs; propodeum usually evenly rounded in profile and without distinguishable base and decl ivity 5 5a) Head with obvious median streak free of punctures and hairs (Fig. 2), in mounted specimens a median crease may also be present in this area (but this is not evident in living or freshly killed specimens); head elongate and narrow, head index 89; females and males dark brown or black; head of female trapezoidal in shape abdita n.sp. b) Without this combination of characters; head either without median hair-free streak, or head nearly as broad as long; head never with median crease in mounted specimens; males and females either light yellow or, if black, then head of female not trapezoidal in shape 6 6a) Large species 1.8 mm in total length with head 0.429 0.009 mm in length; head index 96; head thick and robust in profile; shaped as in Fig. 18; males and females yellow or light brownish yellow; wings clear and nearly colorless pergandei Forel b) Small species 1.1 mm in total length; head 0.318 0.002 mm in length, head index 77; head flattened above and slender in

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26 profile; males and females dark brown to black; wings heavily and entirely infuscated with dark brown xenovenenum n. sp. 7a) Dorsal surfaces of head with moderately numerous hairs nearly entirely of the same short length (Figs. 6, 26) 8 b) Dorsal surfaces with sparser hairs, these distinctly uneven in length (Fig. 10) g 8a) Rear of head and anterior portion of gaster lightly to moderately infuscated with brown; eyes with 3 or 4 facets; females yellowish to light yellowish brown; female eyes very large, eye index 41 carol inensis Forel b) Head and gaster without infuscation; uniformly pale yellow, some specimens nearly whitish; eyes with 2 facets; females dark brown to black; female eyes small, eye index 33. reinerti n.sp. 9a) Comparatively large size; body length 1.58 mm; head length 0.491 0.004 mm; head and gaster usually weakly infuscated; subterranean texana Emery b) Small size, body length 1.34 mm; head length 0.363 0.003 mm; entirely light brownish yellow without trace of infuscation on any areas; arboreal cortical is Forel *!• (£• ) tennesseensis and S. ( D ) texana were not found in Florida in the present study, and previous records seem doubtful. It is possible that these species will eventually be found in Florida.

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27 1 Solenopsis ( Diplorhoptrum ) abdita n.sp. Diagnosis : Workers pale colored, and densely covered with short hairs. Head strongly marked with prominent punctures but with a clear median streak free of piligerous punctures. Eyes reduced to one facet, inconspicuous. Head broader in proportion to length than in tennesseensis and thorax more convex in profile. Females large and dark colored, the head uniquely trapezoidal in shape. Wings colorless. Head and thorax with numerous piligerous punctures. Description : Worker : Measurements : Head length 0.361 0.004 mm; head width 0.32 0.002 mm, head index 89, scape length 0.235 0.003 mm, scape index 65. Thorax length 0.444 0.003 mm, total body length 1.56 mm. The preceding' measurements based on nine specimens. Structural Characters : Head longer than wide, rectanguloid with faintly convex sides, the posterior border slightly excised in the center. In some specimens the head is slightly more narrow anteriorly. The eyes reduced to a single facet. Ventral border of head moderately convex in profile. Anterior edge of clypeus widely and angularly separated from dorsal surface of mandible in profile. A flat head (Fig. 25) not present. Promesonotum of thorax weakly convex in profile, propodeal base somewhat more convex. Petiole large in profile with a

PAGE 39

prominent anterioventral tooth and prominent ventral swelling (Fig. 27). From above, petiole and postpetiole nearly equal in width. Postpetiole with rounded sides as seen from above, not trapezoidal. Anterioventral flange of postpetiole seen in profile sharp but very small. Sculpture : All surfaces smooth and shining except for head which is heavily and densely marked with prominent punctures and dorsum of the promesonotum which is moderately marked with weaker punctures. Head has characteristic median streak free of punctures. Pilosity : Head with numerous short hairs. Thorax, petiole, postpetiole, legs, and gaster also with numerous short hairs which may be longer than those on the head (Fig. 1). Color : Entirely light yellow to light yellowish brown. Female : Diagnosis : A rather large, dark colored female with colorless wings. Head distinctly trapezoidal in shape. Head and dorsum of thorax covered with numerous strong piligerous punctures. Differs markedly from S. ( D ) pergandei females in color and head shape. Description : Head length 0.78 mm, head with 0.98 mm, head index 126, scape length 0.67 mm, scape index 86, eye length 0.24 mm, body length 5.5 mm. Structural Characters : Head distinctly trapezoidal, with nearly straight hind border and sides, the head distinctly more narrow in front than behind. Scapes not quite reaching hind

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29 corners of the head. Eyes rather small for Diplorhoptrum females. Ocelli also small for females of this group. Petiole with blunt node, slightly excised above as seen from behind. Postpetiole wider than petiole, trapezoidal as seen from above, wider posteriorly than anteriorly. Pilosity : Head and thorax with numerous hairs arising from strong punctures. Gastric pilosity also abundant but not arising from punctures. A median streak on head free from punctures or hairs as in the worker. Color : Head, thorax, petiole, postpetiole and gaster dark brown. Legs and antennae light greyish yellow. Wings colorless. Male : Unknown Types : Holotype--a worker from Gainesville, Florida, captured with a Naves trap (June 16, 1979). Airport area. C. R. Thompson Paratypes--numerous specimens from Gainesville Airport area, June through September, 1979, C. R. Thompson; three workers and one female from Tall Timbers Research Station, Florida. June, 1975. M. A. Naves. The holotype and several para types will be deposited at the Museum of Comparative Zoology. Paratypes will also be deposited in the Florida State Collection of Arthropods, Gainesville, Florida. Discussion : This species appears superficially close to pergandei on one hand and to tennesseensis on the other. The female, dark in color and with

PAGE 41

a unique head shape, shows that the species is not close to pergandei The punctures on the head are stronger even than in pergandei and the clear median streak on the head free of punctures seems to be a constant character which does not occur in tennesseensis The head is narrower in proportion to length than in pergandei but is noticeably wider than in tennesseensis The dorsum of the thorax is more flattened in tennesseensis than in abdita Scape and funiculus length shorter in abdita than in pergandei This species has been found at Gainesville and Tall Timbers Research Station north of Tallahassee. It was relatively common in the test area near Gainesville although not as abundant as carol inensis The species may not be rare, but merely previously overlooked and/or unrecognized.

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31 2. Solenopsis ( Diplorhoptrum ) carol inensis Fore! Solenopsis texana race carol inensis Forel 1901. Ann. Soc. Entomol Belg. 45:345. Solenopsis ( Diplorhoptrum ) carol inensis Forel Creighton, 1950. Bull. Mus. Comp. Zool 104:236. Type locality: Faisons, North Carolina Types: Museum of Comparative Zoology, Harvard University Range: North Carolina and Tennessee north to lower New England states Diagnosis : A small Diplorhoptrum with a quadrate-shaped head, moderately sized darkly pigmented eyes. Pilosity moderate, piligerous punctures weak. Pilosity on the head short and nearly all of the same length. In profile, often with an anterioventral tooth on the petiole. Head and gaster usually infuscated. Female small with large eyes. Discussion : Described as a characteristic species of North Carolina (Wheeler, 1904b) S^. (D_. ) carol inensis is also a common species in Florida. It is very common in Gainesville, and was found wherever the Diplorhoptrum fauna was sampled throughout the state. It was found in many habitats: palmetto thickets, turkey oak, open sand areas, rocky soil in Homestead, grassy areas, and pine woods. The nests of this species are shallow (less than 20 cm) and quite frequently one turn with a shovel will bring up the colony queen with a small group of brood and workers. A colony can have more than one queen. This species tends to forage more than most other Florida

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32 species in the forest duff, and I have seen it tending mealy bugs. Excavations of an S^. (D_. ) pergandei colony will often bring (D.) carol inensis to light in the same shovelfull. The larvae of S^. (D_. ) carol inensis have a pinkish cast and are smaller than those of S_. (D. ) pergandei The mating flights of this species have not been observed, but I have dug sexual brood in June (6/9/79) and the flights occur during the same months (June through August) as those of S. (D. ) pergandei The sexual s of S_. (D_. ) carol inensis are attracted to light traps, but in smaller numbers than (D_. ) pergandei The sexual s of S_. (D_. ) carol inensis fly earlier in the morning (5-5:30 a.m.). I suspect that the Florida (D_. ) molesta records, and one of S.. (D_. ) laeviceps (Smith, 1930), are based on misidentif ied specimens of S^. (D_. ) carol inensis Types of this species at the Museum of Comparative Zoology have been examined by Dr. William F. Buren.

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33 3. Solenopsis ( Diplorhoptrum ) cortical is Fore! Solenopsis cortical is Fore! 1904. Ann. Soc. Entomol Belg. 48:172. Type locality: Cuba Types: Museum d' Histoire Naturelle, Geneva, Switzerland. None in this country Range: West Indies (Wheeler, 1913; Wolcott, 1948) and southern Florida Diagnosis : Small arboreal species. Head is rectangular and the eyes are large in comparison with other species of the group. Petiole has anterioventral tooth. Hairs are rather sparse, of uneven lengths and do not arise from punctures. The integument is highly shining. Color is yellow or light brownish-yellow, usually without trace of infuscation. Discussion : This is one of the two known arboreal Diplorhoptrum in Florida, but appears to be much rarer than pi eta and is yellowish whereas pi eta is black to dark reddish-brown. Prior to this study, S. ( D. ) corticalis had not been reported from Florida. A series of this species was taken near Manalapan, a coastal town south of Palm Beach in November, 1945, by Dr. William F. Buren. It was found in branches of red mangrove ( Rhizophora mangle L.). It was subsequently rediscovered by Dr. J. C. Nickerson in the same habitat in May, 1980, on Park Key. This species is polygynous and is probably nocturnal, as no foragers were seen in the daylight. Specimens from the Manalapan series have been compared with West Indian material at the Museum of Comparative Zoology by Dr. William F. Buren.

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4. Solenopsis ( Diplorhoptrum ) molesta (Say) Myrmica molesta Say, 1836. Boston J. Natur. Hist. 1:293. Myrmica minuta Say, 1836. Boston J. Natur. Hist. 1:293. Myrmica ( Tetmamorium ) exigua Buckley, 1867. Proc. Entomol Soc. Philadelphia 6:342-3. Solenopsis debilis Mayr, 1886. Zool.-Bot. Gesell Wien, Verh. 36:461. Solenopsis molesta var. validiuscula Emery, 1895. Zool Jahrb. Abt. f. System. 8:278. Solenopsis ( Diplorhoptrum ) molesta (Say), Creighton, 1950. Bull. Mus. Comp. Zool. 104:237. Type locality: Indiana Types: No longer in existence Range: Reported from east and central U.S. from the Gulf States to Canada. Supposedly rare in the southern areas of the Gulf States. Diagnosis : Head and thorax robust, broad in relation to length. In profile the petiole considerably larger than the postpetiole, but seen from above the postpetiole much wider than the petiole. Differs from carol inensis and texana in having a distinctly broader thorax. Hairs are sparse and of mixed lengths. No obvious piligerous punctures. Discussion : It is this species name which has been most abused in the literature. Authors are legion (Browne and Gregg, 1969; Mann, 1911; Robbins, 1910; Rees and Grundmann, 1940; Talbot, 1975; Yensen and Clark, 1977) who list this ant, but give little or no additional information. For

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35 Florida, [D.) molesta is reported from Rockdale, in Dade County, (Nielsson et al 1971) where it was tending Aphis coreopsidis (Thomas), but no further information on the biology is given. Van Pelt (1958) reports this species from Welaka Reserve and observed the ants closely. He noted that what he was tentatively calling molesta did not match specimens he had seen. Van Pelt was one of the few authors (Mitchell and Pierce, 1912; Ross et al 1971; Huddleston and Fluker, 1968 were others) who qualified their identifications and noted the existing taxonomic confusion. At this time I have found no specimens of S_. (fJ. ) molesta in Florida, nor have I seen any in other Florida collections. Van Pelt's specimens are !5. (D. ) carol inensis

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5. Solenopsis ( Diplorhoptrum ) nickersoni n.sp. Diagnosis : A small dark species similar to S.. {D. ) carol inensis in head shape, eye characteristics, thorax, and petiole shape. Antennae and legs pale-colored and strongly contrasting with body color. Description : Worker : Measurements : Head length 0.345 0.003 mm, head width 0.30 0.002 mm, head index 86, scape length 0.241 0.003, scape index 70, funiculus length 0.359 0.004 mm, club length 0.222 0.002 mm. Thorax length 0.384 0.004 mm, body length 1.2 mm. The preceding measurements based on 18 specimens. Structural characters : Head longer than broad (Fig. 14), rectanguloid, with weakly convex sides and straight posterior border. Head in profile with a narrow angle between the clypeus and mandibles. Head in profile moderately flattened. Eyes dark in color with 2-3 facets, similar to carol inensis Thorax in profile (Fig. 13) with moderate meso-propodeal suture, the dorsal outline similar to carol inensis Petiole in profile similar to carol inensis (Fig. 7). Petiole usually without anterioventral teeth. From above, node of petiole a little narrower than postpetiole. Postpetiole with trapezoidal shape as in carol inensis In profile postpetiole with sharp anterioventral flange (Fig. 15).

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37 Sculpture : All surfaces smooth and shining. Piligerous punctures on dorsum of head weak and not noticeably interrupting the surface. Pilosity : Head with rather short, sparse hairs. Thorax with longer hairs in moderate numbers. Gaster also moderately beset with hairs. Color : The head, thorax, petiole, postpetiole, and gaster dark brown; antennae and legs, including coxae, very pale brown, almost whitish. Female : Unknown? Male : Unknown? The purported females and males of nickersoni thus far have not been found with workers. A match was made by a process of elimination. All other dark colored females and males occurring in Florida have been found with conspecific workers. The dark bodies of nickersoni contrasting with the pale colored appendages is a characteristic found in both the workers and the purported females and males, but descriptions await a collection of sexual s with workers. Types : Holotype— a worker from Gainesville, Florida, caught in a Naves trap on June 16, 1979. Paratype material comprises numerous workers collected in Gainesville, Ocala, and Apopka, Florida on various dates with Naves traps. All were collected by C. R. Thompson.

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38 The holotype and several para types will be deposited at the Museum of Comparative Zoology. Paratypes will also be deposited in the Florida State Collection of Arthropods, Gainesville, Florida. This species is named in honor of Dr. J. C. Nickerson, Division of Plant Industry, Gainesville, Florida. Dr. Nickerson, over a period of several years, has greatly aided and encouraged me in my myrmecological studies. Discussion : S. (D. ) nickersoni is readily distinguished from all other Florida ants of this genus by its dark color which contrasts with the light color of its antennae and legs. In structure it is similar to carol inensis including head shape, eye prominence, thoracic shape, and petiole and postpetiole shape. It lacks the prominent head punctures which are typical of pergandei abdita and xenovenenum n.sp. This species has been found in Florida at Gainesville, Ocala, Apopka and .Myakka State Park. The species, from data collected in 1979 at Gainesville, appeared to be rare. It was caught in only one area and in one trap position out of 100. In 1980, however, it has been taken in April and June at nine trap locations in both open field and wooded areas. The venom of this species has not been analyzed. In two instances, workers of nickersoni were attracted to a second (or third) larval instar of Diaprepes abbreviatus (L.), the Sugar Cane Rootstalk Borer, in a Naves trap, and were able to kill and dismember the weevil larva. This occurred on May 13 and June 9, 1980, near Plymouth, Florida, in a wooded area probably relatively free from

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insecticides. (D.) nickersoni was not found in any citrus grove area near Apopka or Orlando which had been treated by insecticides herbicides.

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40 6. Solenopsis ( Diplorhoptrum ) pergandei Fore! Solenopsis pergandei Forel, 1901. Ann. Soc. Entomol Belg. 45:343. Solenopsis ( Diplorhoptrum ) pergandei Forel. M. E. Smith, 1947. Amer. Mid. Natur. 37:568. Solenopsis ( Diplorhoptrum ) pergandei Forel Creighton, 1950. Bull. Mus. Comp. Zool 104:237. Type locality: Faisons, North Carolina. Types: Museum d' Histoire Naturelle, Geneva, Switzerland. None in this country Range: Virginia and south to Florida, west to Louisiana. Diagnosis : This clear-yellow Diplorhoptrum is the largest species of this subgenus in Florida. The worker is approximately 1.8 mm long while the large females are 5.5 mm long. It also differs from other Florida species in its robust head and thorax. Piligerous punctures on head numerous and distinct. Head quadrate, only a little longer than broad, convex dorso-ventrally in profile. Discussion : This species is common in Florida, and was found over the entire state. It does not leave any surface indication of its nests except during May through August in Florida when it constructs crenelated tumuli the night before a mating flight (see Section 2). This ant prefers to nest in areas which are quite dry and where the soil is compacted such as lawns and woods trails. I have found it in large numbers under a baseball diamond in full midday sun. In

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Mississippi, it was nesting in soil and rotting stumps (Smith, 1931) In Florida, Smith (1944) found it constructed small crater nests in semiboggy ground near scrub and in loam beneath moss or pine needles Van Pelt (1958) found it in quite well -drained areas. Whitcomb et a (1972) found that it built flat honeycombed mounds about 1 foot deep canefields. He observed that the species seemed to be thriving and was strictly nocturnal. The Whitcomb et al observations seem questionable for :S. ( fJ. ) pergandei and may be based upon a misdetermi nation.

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42 7. Solenopsis ( Diplorhoptrum ) picta Emery Solenopsis tenuis Mayr, 1886. Zool-Bot. Gesell. Wien, Verh. 36:262. Nec. S. tenuis Mayr 1877. Solenopsis picta Emery, 1895. Zool Jahrb., Abt. f. System. 8:278. Solenopsis picta var. moerens Wheeler, 1915. Bull.Amer. Mus. Natur. Hist. 34:393. Solenopsis ( Diplorhoptru m) picta Creighton 1950. Bull. Mus. Comp. Zool. 104:237-238. Type locality: Florida Types: Museo Civico di Storia Natural e "Giacomo Doria," Genoa, Italy Range: Gulf States from Florida west to Texas Diagnosis : An arboreal species living in tree twigs. It has a strong mesopropodeal impression, and the promesonotum and propodeum are both strongly convex in profile. Petiolar node set forward from the petiolar-postpetiolar juncture. Hairs are sparse, and of various lengths, and do not arise from punctures. The body shining. Color black, including appendages. A color variant occurs which is paler, often reddish brown. Discussion : This species is common throughout Florida and the southeastern states, but is limited to habitats with dead wood and twigs in which to nest. It is a polygynous species, easily reared in the laboratory. I have a colony captured two years ago, July 23, 1973, which produced sexual s this past May. The sexual s are not attracted to light traps. Van Pelt found this species most commonly in bayhead areas (1958)

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43 8. Solenopsis ( Diplorhoptrum ) reinerti n.sp. Diagnosis : A small pale species. Eyes small but darkly pigmented. General characters of workers similar to carol inensis but queens dark in color except for pale appendages, with small eyes and ocelli. Description : Worker : Measurements : Head length 0.336 0.003 mm, head width 0.285 0.003 mm, head index 85, scape length 0.225 + 0.003 mm, scape index 67, funiculus length 0.332 + 0.006 mm, club length 0.207 0.004 mm. Thorax length 0.359 0.004 mm, body length 1.58 mm. The following measurements based on 12 specimens. Structural characters : Head quadrate, longer than broad with weakly convex sides and straight posterior border. Eyes small but pigmented, with two or three facets. Mandibles with four teeth. Thorax similar in structure to carol inensis Propodeum smoothly rounded in profile without definite base or declivity. Petiole similar in shape to that of carol inensis but without ventral concavity and the anterioventral teeth characteristic of carol inensis (Fig. 27). Postpetiole a little wider than petiole seen from above and weakly trapezoidal as in carol inensis Postpetiole shorter in proportion to length than in carol inensis.

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44 Sculpture : Head with noticeable but small punctures, these much weaker than in pergandei tennesseensis abdita or xenovenenum n.sp. Remainder of integument smooth and shining. Pilosity : Head with numerous short hairs, thorax with less numerous, somewhat longer hairs. Color : Pale yellow or very pale brown, the integument largely transparent. Female : Measurements : Head length 0.54 mm, head width 0.54 0.002 mm, head index 100, scape length 0.40 mm, funiculus length 0.52 mm, scape index 74, body length 2.7 mm. Structural characters : Head as long as broad with convex sides and straight or very slightly concave posterior border. Clypeal teeth weak. Mandibles each with four teeth. Eyes and ocelli small. Thorax distinctly narrower than the head. Petiole with a high node, and without anterioventral teeth. Postpetiole with anterioventral flange. Wider than petiole as seen from above and weakly trapezoidal. Sculpture : Head with numerous well marked punctures. These are weaker but noticeable on the thorax. Pilosity : All surfaces with numerous hairs of moderate length. Color : Head, thorax, petiole, postpetiole, and gaster dark brown. Mandibles, scapes, funiculi, and legs pale yellow or pale brown.

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45 Male : Unknown Types : Holotype a worker taken by core sod sampling in Dade County, Florida, on July 29, 1974, by J. A. Reinert. Paratypes are numerous workers and females collected by J. A. Reinert. Other paratypes are one female (and workers later reared by her) collected on June 23, 1979, in Gainesville, Florida, by C. R. Thompson. The holotype and several paratypes will be deposited at the Museum of Comparative Zoology. Paratypes will also be deposited in the Florida State Collection of Arthropods, Gainesville, Florida. This species is named in honor of J. A. Reinert who was the first to capture this cryptic new species. Discussion : Very little is known about this new species. J. C. Trager (Department of Entomology and Nematology, University of Florida) found sexual s and workers of this species beneath a stone at the edge of woods on June 29, 1980. He collected reinerti males at a blacklight at 5:45 a.m. on June 26, 1980. The workers of this species are so similar to those of carol inensis that identifications remain questionable if only workers are available. The dark brown to black female, however, is so different from the large-eyed, reddish-yellow female of carol inensis that it is clear that two taxa are involved. Although presently known from only two Florida localities, the species may prove to be common and widespread.

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46 9. Solenopsis ( Diplorhoptrum ) tennesseensis M. R. Smith Solenopsis ( Diplorhoptrum ) lonqiceps M. R. Smith, 1942. Proc. Entomol Soc. Wash. 44:210. Preoccupied by Forel, 1907. Solenopsis ( Diplorhoptrum ) lonqiceps M. R. Smith. Creighton, 1950. Bull. Mus. Comp. Zool 104:236-236. Solenopsis ( Diplorhoptrum ) tennesseensis M. R. Smith, 1951. _In. Muesebeck, U.S.D.A. Agr. Monog. 2:814. N. name. Type locality: Hamilton Co., Tennessee. Types: United States National Museum, Washington, D. C. Range: Florida west to Texas and north to latitude of Tennessee. Diagnosis : We did not find this subterranean species in Florida in spite of previous records. It has probably been confounded with the new species S. ( P_) xenovenenum (D. ) tennesseensis is unusual in having a slender head. The thorax in profile is straight dorsally and the propodeum has a distinct base and declivity. Head and thorax with numerous short hairs arising from distinct punctures. It differs from .S. (D. ) abdita in not having a clear median streak free from punctures and hairs on the head. Discussion : This study has shed no new light on the biology or distribution of S. (D. ) tennesseensis Little information is present in the literature. This species is known primarily from the type series. The range given by Creighton (1950) may not be accurate.

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47 10. Solenopsis ( Diplorhoptrum ) texana Emery Solenopsis pollux var. texana Emery, 1895. Zool Jahrb., Abt. f. System. 8:278. Solenopsis texana Fore! 1901. Ann. Soc. Entomol Belg. 45:345. Solenopsis rosella Kennedy, 1938. Can. Entomol. 70:232. Solenopsis ( Diplorhoptrum ) texana Creighton, 1950. Bull. Mus. Comp. Zool. 104:238. Type locality: Texas Types: Museo Civico di Storia Naturale "Giacomo Doria", Genoa, Italy. A questionable series is at the Museum of Comparative Zoology at Harvard. Range: Central Texas and southeastern states north to Canada Diagnosis : Similar to molesta but head more slender, thorax distinctly more slender. Postpetiole a little wider than the petiole seen from above. Hairs sparse and of mixed lengths. No piligerous punctures. Head and gaster often weakly infuscated. S. (D_. ) texana is larger than carol inens is and the hair patterns are different. The small females with the very large eyes seem to be unique to carol inensis Discussion : I have not been able to find this species in Florida. Although Krombein et al. (1971) list this species from Florida, I suspect examination of the specimens would show them to be carol inensis Authentic specimens of S. (D.) texana may eventually be found in the state.

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48 1 1 Solenopsis ( Diplorhoptrum ) truncorum Forel Solenopsis texana race truncorum Forel 1901. Ann. Soc. Entomol. Belg. 45:346. Solenopsis molesta var. castanea Wheeler, 1908. Bull. Amer. Mus. Natur. Hist., 24:430. Solenopsis ( Diplorhoptrum ) truncorum Creighton, 1950. Bull. Mus. Comp. Zool. 104:239. Type locality: Faisons, North Carolina Types: Museum d'Histoire Naturelle, Geneva, Switzerland. Range: Southeastern U.S. and west to the Rocky Mountains. Diagnosis : A large, dark-colored species with rather sparse scattered hairs of mixed lengths. This species is common in the mountains of the western U.S., but also occurs in the eastern Appalachian Mountains. Discussion : The large dark brown castanea was synonymized under truncorum by Creighton (1950). No types of truncorum are present in this country, but the types of castanea were compared with various Florida species by Dr. William F. Buren. The Florida specimens did not match the types of castanea I have not found this species in Florida, although Smith (1979) lists the species as occurring in this state.

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12. Solenopsis ( Diplorhoptrum ) xenovenenum n.sp. Solenopsis tennesseensis Krombein, Hurd, Smith, Burks. Catalog of Hymenoptera in America North of Mexico. Smithsonian Institution Press, Washington, D.C. 1979. p. 1388. in part nec M. R. Smith Diagnosis : Very small yellow species. Head with prominent punctures, pilosity short and numerous on all surfaces. Head elongate as in tennesseensis Eyes reduced to a single facet. Males and females with characteristic darkly infuscated wings. Description : Worker : Measurements : Head length 0.317 0.002 mm, head width 0.245 0.002 mm, head index 77, scape length 0.191 0.002, scape index 60, funiculus length 0.296 0.003 mm, club length 0.191 0.002 mm. Thorax length 0.336 0.004 mm, body length 1.1 mm. The preceding measurements based on 18 specimens. Structural characters : Head (Fig. 30) distinctly longer than broad with weakly convex sides and straight or slightly excised posterior border. Antennal scapes reaching 2/3 the distance from insertions to hind corners of head. Eye reduced to one facet, usually pigmented. In profile head somewhat flattened dorsal ly, slightly convex ventral ly. Anterior edge of clypeus angularly separated from dorsal surface of mandibles seen in profile.

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Thorax weakly convex; propodeum rounded without definite base or declivity (Fig. 29). Petiole without anterioventral tooth. From above the petiole and postpetiole are about the same width. Postpetiole with rounded sides. Sculpture : Dorsum of head covered with distinct punctures but these not as strong as in tennesseensis or abdita Dorsum of promesonotum also with some weak punctures. All other surfaces smooth and shining. Pilosity : Hairs short and numerous on all surfaces. There may be some longer hairs on the thorax, gaster, and petiole. Color : Yellow to pale yellowish brown. Female : Measurements : Head length 0.59 mm, head width 0.64 mm, head index 108 mm, scape length 0.46 mm, scape index 78, funiculus length 0.60 mm, total body length 3.24 mm. Structural characters : Head quadrate, a little longer than broad with both sides and occipital border nearly straight or only slightly convex. Scapes nearly reaching hind corners of the head. Ocelli rather small, measuring 0.02 mm in diameter and separated from each other by at least one diameter. Thorax slightly narrower than head. Petiole without anterioventral tooth. Node of petiole with slightly excised superior border seen from behind. Petiole and postpetiole of the same width. Postpetiole weakly trapezoidal as seen from above, wider posteriorly than anteriorly.

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51 Sculpture : Head with scattered moderate punctures; mesonotum with weak punctures. Pleurae of propodeum, petiole, and postpetiole weakly striate or shagreened. All other surfaces smooth and shining. Pilosity : Body and appendages with numerous short hairs. Wings with dark brown veins and stigma, membranes also completely infuscated with brown. Color : Entire body including appendages brownish to dark brown. Male : Measurements : Head length 0.40 mm, head width (including eyes) 0.50 mm, thorax length 1.08 mm, petiole length 0.34 mm, eye length 0.19 mm, body length 2.82 mm. Structural characters : Antennae 12-jointed, last two joints and particularly the last joint longer than other funicular joints, but not enlarged or clublike. Eyes occupying about one-half of head length, ocelli 0.065 mm in diameter. Mandibles weak, each with 2 or 3 teeth. Head trapezoidal in shape. Thorax without Mayrian furrows on the mesonotum. Petiolar node with slightly concave superior border. Sculpture : Head and dorsum of thorax with weak punctures. Propodeum sculptured with striato-punctate markings. Petiolar node punctate. Pilosity : All surfaces with numerous short hairs. Color : Dark brown, including the appendages. Wing veins and membranes completely infuscated with brown.

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52 Types : Holotype— a worker collected by Naves trap on June 16, 1979, by C. R. Thompson. Para types are numerous workers taken in Naves traps June to October, 1979. The holotype and several para types will be deposited at the Museum of Comparative Zoology. Para types will also be deposited in the Florida State Collection of Arthropods, Gainesville, Florida. Discussion : This species is so named because it was found by Dr. Tappey Jones (Univ. of Georgia) to have (5Z,8E)-3-heptyl-5-methyl pyrrol izidine as the main constituent of its venom. This compound is new to biology. The species is common throughout the state in many habitats. Males and females have been observed in an afternoon flight at Homestead, Florida, in July, 1964. Males have been taken from a spider web in Gainesville, Florida, on July 30, 1978, and from a light trap in Miami Beach (June 3, 1947). This is the smallest Diplorhoptrum species in the United States and has been taken from under stones, unlike most other species of the subgenus in Florida.

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PLATE 1 Figure 1. Lateral view of worker of S.. (fJ. ) abdita n. sp. (65X) Figure 2. Head of the worker of S. (J). ) abdita n. sp. (120X) Figure 3. Petiole and postpetiole of worker of S. (D. ) abdita n. sp. (340X) Figure 4. Dorsal view of worker of S_. (fJ. ) abdita n. sp. (50X)

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54

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PLATE 2 Figure 5. Lateral view of worker of S. (p..) carol inensis Fore! (60X) Figure 6. Head of the worker of S. (D.) carol inensis Fore! (130X) Figure 7. Petiole and postpetiole of worker of S. {Q. ) carol inensis Forel (290X) Figure 8. Dorsal view of worker of S_. (D. ) carol inensis Forel (56X)

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PLATE 3 Figure 9. Lateral view of worker of S. (D.) cortical is Fore! (90X) Figure 10. Head of the worker of S. (£. ) cortical is Fore! (200X) Figure 11. Petiole and postpetiole of worker of .S. ([J. ) corticalis Forel (360X) Figure 12. Dorsal view of worker of S^. ( D. ) cortical is Forel (65X)

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PLATE 4 Figure 13. Lateral view of worker of Su (D.. ) nickersoni n (75X) Figure 14. Head of the worker of S. (D. ) nickersoni n. sp (120X) Figure 15. Petiole and postpetiole of worker of S^. (D_. ) nickersoni n. sp. (420X) Figure 16. Dorsal view of worker of S_. ( [J. ) nickersoni n. (65X)

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60

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PLATE 5 Figure 17. Lateral view of worker of S. (D.) pergandei Forel (79X) Figure 18. Head of the worker of S. (D.) pergandei Forel (98X) Figure 19. Petiole and postpetiole of worker of S. (D_. ) pergandei Forel (165X) Figure 20. Dorsal view of worker of S. (D.) pergandei Forel (75X)

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PLATE 6 Figure 21. Lateral view of worker of S. (D.) picta Emery (70X) Figure 22. Head of the worker of S. (D.) picta Emery (140X) Figure 23. Petiole and postpetiole of worker of S_. (D. ) picta Emery (378X) Figure 24. Dorsal view of worker of SL (D.. ) picta Emery (70X)

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64

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PLATE 7 Figure 25. Lateral view of worker of S.. (fJ. ) reinerti n. sp (90X) Figure 26. Head of the worker os S^. ( fJ ) reinerti n. sp. (140X) Figure 27. Petiole and postpetiole of worker of (fJ. ) reinerti n. sp. (460X) Figure 28. Dorsal view of worker of S^. {d_. ) reinerti n. sp. (50X)

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PLATE 8 Figure 29. Lateral view of worker of S_. ( D. ) xenovenenum n. sp. (83X) Figure 30. Head of the worker of S. (D_. ) xenovenenum n. sp. (1 BOX) Figure 31. Petiole and postpetiole of worker of S^. ( D_. ) xenovenenum n. sp. (460X) Figure 32. Dorsal view of worker of S_. (D_. ) xenovenenum n. sp. (84X)

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68

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PLATE 9 Figure 33. Cluster of mating flight tumuli of S_. (fJ. ) pergandei Forel Figure 34. Mating flight tumulus of Su (fJ. ) pergandei Forel Figure 35. Mating flight tumulus of S_. (jD. ) pergandei Forel

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71 Section II Subterranean Distribution of Diplorhoptrum Species Mosaic distribution of ant species is well documented in cacao plantations (Majer, 1972; Leston, 1973), but these studies involved arboreal species in easily sampled ecological niches, i.e., cocoa trees. Nothing was known of the distribution of Diplorhoptrum species below ground, particularly as no surface structures are constructed by these ants, with the exception of S. (D. ) pergandei mating flight tumuli. Accordingly, 5x10 meter grids were set up, and experimental trapping was begun in June, 1979. The results were immediate and surprising. Of 100 traps put down June 17, in 24 hours 59 were positive for ants and, of these, 43 contained Diplorhoptrum Diplorhoptrum were captured in as many as 75 per cent of the traps during July and August and as few as 3 per cent in January. Some traps contained over 300 ants. An example of the results is shown in Fig. 36 for the longleaf pine-turkey oak woods. Five species of Diplorhoptrum were captured in the traps during this study. All were present in the first set of traps put down on June 17. Numbers of traps in which each Diplorhoptrum species was captured throughout the year are presented in Figs. 37 and 38. It is evident that S. ( D. ) carol inensis was the dominant subterranean ant in both habitats. S. (D.) pergandei was absent from the field habitat, and present at only two trap locations in the woods grid. S. (D. xenovenenum also had a distinct pattern in that they were captured in only 2 traps in the field, but were evenly distributed in the wood.

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72 53 55 >>>!>!> *//////*/// '////////// t / / S / / > t////S/////i 1 1/ s / / / / / / /////// t////////// '///// / / / mmm 60 £8:: m vrr ft / / / })>))}} ///ss///* S////SS/* /////s/s, / / / / s / s / / s / / / s / 63 62 73 1 1 1 1 1 1 1 1 1 1 1 1 .v.V\\\\\\ m 80 W: &y s / / / s / / JUs /////// / • ///////// /ssss/s/s// S////S/S/ ,•_ S/////S///S •I sssssssssss ////////s// w nana 85 84 TrrrrrrrTTT UPC W: 1 1 1118! : ?5: : Xv: •:•!•!•!•!•!•!•!•!•!•!*' "ft'***/** S. (D.) carol inensis S. (D.) xenovenenum n. sp. S. (D.) abdita n sp. S. (D.) pergandei Other genera It Figure 36. Example of Naves trap samples of Diplorhoptrum and other species distribution in a long leaf pineturkey oak woods on June 24, 1979, at Gainesville, Florida.

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75 Ant activity dropped sharply between October and November and began to increase the following year between April and May. Having observed the sharp cessation of activity in the fall, I suspected soil temperatures might be a factor and began to monitor them. On April 15 the field soil temperatures taken at 14 cm were 15.3, 16.3 and 17.0 C. The wood soil temperatures were 16.0, 16.3 and 17.0 C. By Hay 16 a distinct increase was evident: field soil temperatures were 23.3, 23.3 and 24.0 C while wood soil temperatures were 21.0, 21.5 and 21.5 C. These data indicate that soil temperature may be a major factor in seasonal Diplorhoptrum activity patterns. The major question posed by these collection data is how many nests and of what species are present? Estimates of colony numbers and territorial sizes can be made based on the following assumptions: 1. Few ant species build one-chambered nests, and all known Solenopsis build multi -chambered nests. It can be assumed Diplorhoptrum have multi -chambered nests. 2. All known Solenopsis have discrete nests. Large populations covering large areas without discrete nests probably do not occur in Diplorhoptrum species. Diplorhoptrum are here assumed to have discrete nests and foraging areas which do not extensively overlap. 3. From the appearance of S. (D.) pergandei tumuli clusters, which are constructed following rain (Fig. 33), the network of chambers and tunnels below may be assumed to be diffuse. The nest probably occupies a region comparable to the size of the cluster on the surface and not more than 1 or 2 meters in area. 4. Each ant colony controls available food sources over as wide an area as possible. Dominant species may be assumed to control large

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76 areas; subdominants to control proportionately smaller areas. 5. Whether dominant or subdominant, the closer a food source is to a nest, the more likely that colony will be able to successfully exploit and control the food source. 6. Subdominants or non-dominants probably can not maintain complete control over foraging areas unless near their nests. Specific traps (i.e., Meter 8 with S. 0L) nickersoni or Meters 70 and 71 (Fig. 37) with S_. (JD. ) pergandei ) were nearly always positive with certain subdominants, therefore it is probable that these traps were located near a nest of the subdominant, and that a single colony of the subdominant is indicated by each of these locations. 7. It can be assumed that any trap location in which one species was consistently collected and which was nearly always positive is likely to be close to the nest location of a dominant. Therefore the nest of each subdominant, and the nest areas of each dominant should be countabe with reasonable accuracy. With these assumptions, and the summation method of assembling the data, the nesting pattern and general foraging areas of the various species sampled can be estimated. Data were summed by counting the numbers of traps positive for each species, then multiplying each number by the percentage of the time a trap was positive for that species. For example, S^. ( D. ) carol inens is was present, in Trap 12,5 out of 7 or 77.7% of the times that the trap was positive with Diplorhoptrum Multiplying 5 x 77.7% gives an experimental summation number of 544. The summation numbers were then arbitrarily divided into four groups and assigned to a pattern series, as shown in Figs. 39-43. From these patterns, rough estimates of the shape of foraging areas for each individual nest can be drawn.

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77 S. (D. ) carol inensis mosaic patterns were the most complex. In the field there appear to be four colonies with wide-ranging territories (Fig. 39). Foraging areas of two additional colonies appear to be only partially present in the grid. In the woods site, there is probably one large colony and a second smaller colony with a much smaller foraging area around Meter 82 (Fig. 41). The colony and foraging patterns of S. (D_. ) abdita and S_. ( J). ) xenovenenum are less complex. There appear to be 4 colonies of S. (D_. ) abdita in the field grid and only probably two colonies in the woods, with perhaps an incipient colony in Meters 84-85 (Figs. 40,42). S. (D. ) xenovenenum occupied only one meter in the field site, but appeared to have three colonies (Fig. 43) and part of the foraging territory of a fourth in the woods site. The data in Figs. 39-43 are subject to more than one interpretation and boundaries could easily be drawn somewhat differently. In addition, the true correlation of colony numbers and territories indicated by trapping data with those actually present in the field remains unknown. It is hoped that the Naves trap method may eventually be found to indicate true Diplorhoptrum territories and colony numbers. In the field site S. (D. ) carol inensis is the dominant species while S. (D. ) pergandei is an occasional dominant, or to use Majer's (1972) terminology sensu strictu a sub-dominant, i.e., a species capable at times of becoming a dominant. Yet many more S_. (D. ) pergandei queens were found during field excavation and in light traps than were S. (D. ) carolinensis. This would be consistent with a species which does not expend energy in large queens and mating flights, but whose small queens may mate mostly in the nest and remain in the nest to produce large,

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78 diffuse colonies. Dr. J. C. Nickerson collected a colony of S^. (D_. ) carol inens is which had 6 queens. In the laboratory a number of (D_.) carol inensis queens will found a nest together amicably, and will remain together without fighting after workers are reared. These data support the low energy—small queens hypothesis. A second method of data analysis undertaken was a breakdown of positive trap counts by month of the year as shown in Figs. 44 and 45. Concentrations and suspected nest locations generally coincided with those obtained from the summation method. Comparisons must be made with caution, however, as data presented in Figs. 44 and 45 cover a year while Figs. 39-43 include data from a five month period. The greatest weight was placed on the five month summation study results, after the tremendous fluctuations in species location data were noted. Fluctuation in colony locations was greatest following the relative inactivity of the winter months. Twenty traps remained positive for the same Diplorhoptrum species over the entire year. Intramonthly repeatability (June to Oct.) was high: 90% + 2.0, while intermonthly repeatability was substantial: 63% + 3.0. The number of traps common to the same species on June 17, 1979 and June 18, 1980 (first and last experimental dates) was eight, while the number of corresponding traps with different species was 11 and the remaining traps were positive on only one day or not at all. In addition to the summation and by^month analyses of Diplorhoptrum distribution, a third method was proposed based on the following observations and hypothesis: during November through February, Diplorhoptrum activity was low, with S. ( D. ) pergandei and S. (D. ) abdita activity ceasing entirely. If one makes the assumption

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79 Summation Values o-300 O 301 -600 ED 601-1 ,000 B 1,000+ Figure 39. Five month (June-Oct. 1979) summation of the distribution by trapping of S. ( D ) carol inensis in an open field at Gainesville, Florida.

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Figure 40. Five month (June-Oct., 1979) summation of the distribution by trapping of S. ( D ) abdita in an open field at Gainesville, Florida.

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81 Summation Values 0-300 (ED 301 -600 601-1 ,000 1 ,000+ Figure 41. Five month (June-Oct. 1979) summation of the distribution by trapping of S_. ( D_. ) carol inensis in a long leaf pineturkey oak woods at Gainesville, Florida.

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70 71 90 91 52 SO 72 89 92 57 64 77 97 58 63 78 83 98 59 82 99 81 00 82 5i 6S 5! 56 67 66 65 73 74 75 87 86 93 94 76 95 96 Summation Values ffiO-50 QZI51 -200 201-700 700+ Figure 42. Five month (June-Oct. 1979) summation of the distribution by trapping of S. ( D. ) abdita in a long leaf pine-turkey oak woods at Gainesville, Florida.

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83 Summation Values 0-50 ED 51 -200 600+ Figure 43. Five month (June-Oct., 1979) summation of the distribution by trapping of S^. (D_. ) xenovenenum in a long leaf pine-turkey oak woods at Gainesville, Florida.

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84 Figure 44. Number of months each trap site in an open field at Gainesville, Florida, was positive for three three species of Diplorhoptrum (June 1979-June 1980)

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35 Figure 45. Number of months each trap site in a long leaf pineturkey oak woods at Gainesville, Florida, was positive for three species of Diplorhoptrum (June 1979-June 1980).

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86 that the ants do not forage far from the nest in the cold, it should be possible to map nest locations more accurately than at other times of the year. When the winter distribution maps were prepared, however, it was found that many traps were positive, but only once or twice, making pattern discernment impossible. Figures on the distribution of IS. (ID.) pergandei and S^. ( J). ) nickersoni were not included, as these species were extremely localized. S. ( D_. ) pergandei appeared only in woods traps with one established nest in or near Meter 70, which included territory in Meters 69-72. Su ( D_. ) pergandei is a sub-dominant. It successfully excluded S. (D_. ) carol inensis from Meter 70 for an entire year. S_. (D_. ) nickersoni appeared to have an even more scattered distribution except for captures by Traps 8 and 13. It is also a sub-dominant, able (Fig. 40) to exclude S_. (D. ) carol inensis from Meter 8, but not S. (D_. ) abdita Only Diplorhoptrum species were taken from the field traps in this study, but other ant genera came to the woods traps: Pheidole dentata Pheidole floridana Pheidol e metallescens Brachymyrmex depil is and (one collection) Solenopsis geminata Records of these ants were kept but are not included in this study. It is evident from the approximately 3 to 14% of the traps which captured this group, that the greatest competitors Diplorhoptrum have among other ants are species of Pheidole In summary, totally unexpected and extremely large numbers of workers of five Diplorhoptrum species were found in an open field and in long leaf pine-turkey oak woods. Three of the species were new. By constructing a system of assumptions and by summing numbers of positive traps and percentage of those traps for each species, diagrams of

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87 possible nest numbers and territorial boundaries were constructed. S. ( D. ) carol inensis was the dominant species in both habitats while S. ( [J. ) abdita was common, particulari ly in the field. Of the less common species, (D. ) xenovenenum was more often found in the woods, S^. (D. ) nickersoni was rare in both habitats and S. (D_. ) pergandei was only in the woods site. This was a beginning study of previously unknown or poorly known species. From the preliminary data no habitat preferences for the various species should be inferred at this time.

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88 Section III The Mating Flights of S. (D.) pergandei Solenopsis ( Diplorhoptrum ) pergandei is the largest species of the subgenus that occurs in Florida. It is also the only species that constructs a visible structure (tumulus) surrounding its nest opening at the soil surface. From June through early September, within 24 hours after a rain, S^ (D_.) pergandei constructs unique, crenelated tumuli for early morning mating flights. Tumuli Construction The tumuli are constructed with passages wide enough for several females to pass (ca. 6 mm ) and with walls twice or more their body height (ca. 5-10 mm). I have seen some tumuli 16 cm in diameter. One benefit of these passages is probably an increase in the number of sexuals that can remain at the soil surface in preparation for a flight while still remaining under the protection of the workers. On June 23, 1979, at 4:20 a.m., I observed sexuals massed at the surface even though this flight did not occur until nearly 6 a.m. A second function of these tumuli is probably to present a flight take-off surface for the departing sexual forms, although I have observed the heavy females climbing up grass blades near the nest. On mornings when flights did not occur, the ants constructed tumuli of two additional types. These I have called "closed" tumuli and "digging-out" tumuli. The closed tumuli were sometimes constructed on

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89 mornings following rain when flights did not occur. The ants constructed chambers at ground level, then formed a thin roof of soil pellets with worker-sized entrances. No flights were ever observed from these structures. Digging-out tumuli apparently were for exactly that purpose. Other conditions apparently were not favorable for flights, and the ants were most likely repairing passages which had collapsed with the rain. These tumuli were simply piles of excavated soil deposited near the entrance. Flight Factors Preliminary studies in the summer of 1978 suggested that S_. (D_. ) pergandei mating flights did not occur unless there had been measurable precipitation during the previous 24 hours. Data gathered on 30 flights from June to September of 1979, when they ceased in the Gainesville area, showed that 83% (25) of the flights occurred following a rain. On seven additional mornings tumuli were constructed but no flights occurred. The ants frequently constructed closed, digging-out and a few crenelated tumuli on non-flight mornings. This indicated that conditions became unfavorable during the night, or that additional stimuli utilized by the ants to initiate flight were not favorable. As the summer progressed, mating flights occurred slightly later each week. In late June, flights began at 5:50 a.m. In early August, they were beginning at ca. 6:08 a.m. This suggested that an additional factor potentially triggering flights was light. A commercial light meter was used to attempt light readings at flight times. It was so dark in the half hour before dawn when these ants flew that almost no light values were registered. Readings at 6:41 a.m., shortly after a

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90 flight on September 3, 1979, were 0.05 fc with the probe at ground level facing the sky, 1.0 fc facing the eastern horizon, and 1.6 fc at 45 to the horizon. As an alternative to direct light readings, the flight times were recorded and compared with local sunrise times (Fig. 46). Actual flight times recorded were few. I attempted to watch 10-30 nests and rarely saw the actual beginning of a nest flight. It was also so dark that a flashlight had to be used to observe flight activity. It was turned on for a few seconds every five minutes to ascertain flight activity while attempting to keep interference to a minimum. I did notice that I was able by summer's end to arrive at 5:45 a.m. and not miss any of the flights. The graph in Fig. 46 does indeed show a correlation of flight times with time of sunrise. As the days shortened, the flights occurred later in the morning and remained at ca. one half hour before dawn. The occurrence of the wood flights, where dawn was slow to penetrate, at later times than the open meadow flights, also points to light as a triggering factor. Flight and Post Flight Activities When moisture and light levels are favorable, a final unknown stimulus (or stimuli) causes the workers in a S_. (D. ) pergandei nest to begin running about erratically. The winged sexual s become excited and begin to leave the nest. No nest was observed to contain both sexes. Rather, only winged males or winged females were present. The nests containing winged males began flight first. The males, with their smaller and lighter bodies, were quickly in flight. In nests with females flight times were longer. The larger, ponderous females were

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91 CD ^i^^M^^^^od — i 5 ar2 O -rUJ C/0 II II LT) cxi +-> l/l cc CM <3CM o CXI cu +J ro Q >— ,_ 3 "3 1 — O — i 1 1 1 r O o o o o u> m CD (£> <£) tc 6uiiuoiu j.o auiLi cc o C CXI 3 "3 O m o > • ro ro i— "O CD •!iSso O r— C_) Ll_ X>

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92 also more exposed to predators by their slowness to take wing. I saw both Pheidole workers (June 10, 1979) and a worker of Odontomachus brunneus (Patton) on June 26, 1979, carrying off S_. (D_. ) pergandei females. Much predation is probably avoided by the erratic movements of the workers. The impetus of worker movements caused them to spread out by the hundreds over the tumulus and within a radius of approximately 5 cm around it. In this area they frequently confronted workers of other species of ants which were immediately attacked. As a result, the large females were protected by a network of workers within the tumulus area. Although the activities of the workers protected the females quite adequately, after the flight the nest was exposed to extreme danger. The workers did not always close colony entrances and often could be found on the soil surface until midmorning. On three occasions I observed a S^. (JJ. ) pergandei nest being destroyed by Solenopsis geminata I suspect that the only reason more S_. (D_. ) pergandei nests were not attacked was that, after the sun reached them, the tumuli rapidly began to crumble. By 10 a.m. it was virtually impossible to determine whether a flight had occurred: the tumuli had crumbled to a layer of powdered dust on the soil surface. An unexpected observation was the number of flights which were staged from single nests. Nest locations were stable throughout the summer and workers constructed a new tumulus where the old one had collapsed or had been obscured by rain. It was not uncommon for flights to be initiated from a nest every favorable morning for two months or more. I observed one nest from which sexual s flew for nearly the entire summer.

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93 Initially I hypothesized that mated females were accepted by existent colonies after a flight. Nests near the flight study area contained as many as 20-30 deal ate females which I thought were reproducing queens. Observation of nests which had initiated mating flights for several weeks gave another explanation: females were observed with three wings, two wings, one wing and no wings at all during flights. These females, even those with no wings at all, behaved exactly as though they had wings and could take flight. When it became light, and those females with wings had flown, these females retreated back down the nest entrances. Apparently they repeated this behavior flight after flight, progressing from four wings to no wings at all. The wings of female ants have lines of weakness along which they normally break off after the female has gone on the mating flight. I suspect that jostling in the crowded nest caused some wing breakage and that the loss of one wing was enough to prevent flight. It was these unfortunate females who slowly lost all their wings. I was unable to determine the final fate of these females. It is unlikely any were mated since a nest contained only one sex, and I did not observe males near any tumulus containing females. By 8 a.m. S^. (D_. ) pergandei females could be found at a second study site: a USDA light trap at the Insects Affecting Man and Animals Laboratory in Gainesville. If rainwater was standing on the trap roof, large numbers of the males often were caught by their wings in the water film, but few ever entered the trap. When rain did not fall for several days, large flights took place. For example, rain occurred on June 30, 1980, after a dry week. The light trap the following morning contained 2,081 S^. (El.) pergandei alate females, 5 males and 83 dealated

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94 females. Before I arrived, however, a number of these ants had already been carried off by foraging Pheidole workers. Although held in the laboratory several days, no further females shed their wings. It seemed probable that large numbers of these females were mated, particularly since rain afta a dry period would have coordinated a number of colony flights. Examination of 20 dealated and 20 alate S_. (D_. ) pergandei females by Adrian Glover (USDA Fire Ant technician) revealed that all the dealated females but only two of the alates were mated. These data suggest that the 2,081 S. (D.) pergandei females captured June 30, 1980, were mostly unmated. More information is needed to resolve this question. Twenty alate S. (D_. ) pergandei females in groups of five from the light trap were placed on the ground and observed for 15 minutes. Within seconds each female ran quid<3y into holes and under sticks and leaves and took cover. When the cover was removed 15 minutes later, four females were not found, three had begun to excavate, one had removed her wings, and the remainder had simply remained hidden. Although this behavior indicates females may found nests cl austral ly, attempts to induce colony founding in the laboratory have not been successful. In summary, S^. (D. ) pergandei is the only subterranean Florida Diplorhoptrum species which constructs nest structures at the soil surface. It constructs crenelated tumuli from June through early September which are utilized only for mating flights. These tumuli apparently allow more sexual s to remain at the soil surface and offer a surface for flight take-off. Nests produce only males or only females and each nest has many flights during the summer. These flights occur before dawn, and rain in the previous 24 hours is necessary for flight activity.

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95 Section IV The Role of S. (Diplorhoptrum) as Underground Predators Preliminary Experiments The large numbers of Diplorhoptrum found in the ground by Naves trapping (Section II) suggested a further line of research: placing target organisms in the traps to determine whether Diplorhoptrum would prey upon them. In February, 1976, a 15-trap wood plot and a 25-trap field plot were set up and cabbage loopers were used as bait. Since this was early in my Diplorhoptrum research, I was unaware of the relative inactivity of the ants at this time of year. The loopers were killed by S^. (U. ) carolinensis but positive trap numbers remained at only approximately 10 per cent. This experiment was resumed in April, 1976, when three species of Diplorhoptrum killed and fed upon the loopers. Sometimes, in the 48 hours the trap was down, the ants consumed the entire larva except for the hollowed out head capsule left behind. The predatory Diplorhoptrum species were primarily S_. (D_. ) carol inensis but also S_. (JD. ) pergandei and S^. (rj. ) xenovenenum Predation on Fire Ant Females In June, 1976, fire ant females were collected from local nests and placed as bait in Naves traps. When the traps were recovered in 48 hours, seven of the 15 females had been killed and consumed by

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96 S^. (D_.) carolinensis workers. In three of these vials the fire ant queen had been consumed except for large pieces of chitin. In the fourth vial, not even the chitinous pieces of the female were left. Of 100 fire ant queens put out in traps August 8, 1980, eight were found dead. Of these, three died of unknown causes, three were found with S_. (D_. ) carolinensis workers, one with S_. (D. ) xenovenenum workers and one with Pheidole floridana workers. Diplorhoptrum were also found in the traps of eight live queens. In five of those, the Diplorhoptrum workers had been killed and chewed into pieces by the fire ant queen. Further experiments with fire ant females as bait and the role of the Diplorhoptrum species in the control of this pest species are underway. Predation on Diaprepes abbreviatus larvae The Sugar Care Rootstal k Borer Weevil, Diaprepes abbreviatus (L.), threatens citrus in Florida. The larvae feed on citrus roots and develop undergroud for two to three years. The weevil is presently confined to quarantine areas surrounding Apopka and Davie, Florida. In light of the above predation studies, and the fact that the Diaprepes larva spends such a long period of its life underground, it seemed logical to suspect that underground predators could have a strong impact on Diaprepes populations. Preliminary to testing this hypothesis, on July 25, 1979, 100 tunabaited Naves traps were placed at the tree base, drip line and row middles of four citrus groves in the quarantine area which ranged from fully managed, heavily insecticided groves to a grove untreated pestici dally for 20 years. No Diplorhoptrum were found except in the pesticidally untreated Forest City grove.

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97 Further tests were conducted in the Forest City grove and in a control (non-grove) area to determine Diplorhoptrum populations, but results have been erratic: of 50 tuna-baited Naves traps placed in the Forest City grove on August 23, 1979, only three were positive for ants and none with Diplorhoptrum Fifty traps in a non-grove control area in woods (subsequently discovered to be old abandoned grove land) were negative. Of 50 traps placed in the Forest City grove on Sept. 18, 1979, two were positve for S_. ( D_ ) carol inensis In a new control area, 10 traps were positive for S_. ( D_. ) carol inensis two for S_. (D_. ) pergandei and six for S_. ( D_. ) xenovenenum Results of baiting with tuna indicated that at least three Diplorhoptrum species were present in low numbers in the Apopka area. To ascertain the role of Diplorhoptrum in Diaprepes larvae control, 50 Naves traps containing Diaprepes larvae were placed in the Forest City grove on Oct. 26, 1979. No control traps were used. No Diplorhoptrum were captured with the larvae. A second set of traps (n=88) with larvae were put down on May 13, 1980 and left for 72 hours. Fifteen traps were put down in a non-grove area as a control. In the grove, Pheidole spp. killed five larvae in the traps, but there was no detectable predatory activity by Diplorhoptrum In the control area, S_. ( D_. ) xenovenenum and S. (D. ) nickersoni each attacked and killed a larva. These results were repeated, with Diplorhoptrum spp. again killing two of 15 larvae in the control area on June 9 1980. In summary, even in a grove untreated with pesticides for 20 years, Diplorhoptrum populations were low. In control or non-grove areas within the quarantine area Diplorhoptrum populations were higher, and

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98 were capable of killing and eating approximately 15% of the larvae offered in the traps. Although these numbers may not seem significant, if the Diplorhoptrum are capable of killing 15% of the Diaprepes in traps in 72 hours, there is considerable chance that they could kill a significant portion of the larvae over the two or three years the larvae remain below ground.

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SUMMARY This study must be viewed as a preliminary effort in a neglected area of myrmecology. No new species of Diplorhoptrum had been found in North America since 1942. Yet a simple grid pattern of bait traps at Gainesville, Florida, immediately captured three new species. A fourth new species was discovered in randomized sod samples from Dade County, Florida. Thus this group is poorly known in Florida. The bait trap catches and ancillary studies seem to suggest several other conclusions: 1. Bait trap sampling in the grid study varied between 53 and 75 per cent postiive for Diplorhoptrum during the summer months. All trap locations were positive at least occasionally. The data are consistent with information on generalized subterranean predators, which have networks of exploratory tunnels rather than being uniformly present in the soil. Ants that are strictly lestobiotic, always associated with larger ants, could have been expected to show many gaps in their distribution patterns. The data in this preliminary study suggest that there are no distinct gaps in the subterranean spaces patrolled by these ants. 2. Mosaic distribution patterns of the five Diplorhoptrum species captured seem to be suggested by the data. These mosaic patterns are similar to, if not entirely analogous with, the mosaic patterns of arboreal ants in Ghana. 99

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100 3. Diplorhoptrum species are able to kill and dismember insects much larger than themselves, like large Lepidoptera larvae, fire ant queens, and Coleoptera larva. This is probably due to the potency of their venoms. These data again are consistent with widespread generalized predators, rather than with specialized predation as exhibited by other cryptobiotic ants such as Strumigenys and Smithi struma The generalized morphological structure of Diplorhoptrum species is also consistent with that of generalized predatory ants, as contrasted with the highly specialized morphologies of the Dacetine ants. 4. Perhaps the most important finding that arises from this study is the significant lack of general biological knowledge of these ants. The ants were previously thought to be specialized, lestobiotic species with sporadic distributions, yet they are now shown to be generalized, widespread, abundant predators in Florida. An important question is whether or not these or other similar ants have similar roles in other areas of North America and of the world. If there is a network of subterranean ants on a worldwide or very widespread basis, then an important component of ecosystems has been neglected. The paucity of knowledge about Diplorhoptrum is nowhere better seen than in the mating flight data. In spite of much observation, (JJ.) pergandei mating flights were the only flights seen. The other species apparently never construct tumuli. How their sexual s are brought to the surface and what factors trigger their flights is unknown. It is presumed that those species with dark colored sexual s with small eyes and ocelli are diurnal flyers, while species with yellowish sexual s with large eyes and ocelli are nocturnal flyers.

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101 5. Questions this study has raised are the following: a. What is the physiological and behavioral significance of the venom chemistry of these ants? b. Is it possible that there are negative correlations between Diplorhoptrum populations and certain other ant populations such as fire ants? c. Is S. (]3. ) molesta as widespread and common as it is reported to be in the literature, or are these records partially based on misdeterminations in this taxonomically difficult group? d. Are Diplorhoptrum populations sometimes abundant enough to have strong impact impact on the populations of pest organisms such as imported fire ants, Sugar Cane Rootstalk Borer larvae, mole crickets, and root knot nematodes? e. Could Diplorhoptrum species from other areas of North America or of the world be imported into Florida or the southeastern states as biological control agents?

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GLOSSARY Al ate— Having wings Antenna! club—The last two segments at the tip of the antenna which, in Solenopsis are enlarged to form a club Base— Of propodeum, the anterior dorsal surface of the propodeum Crenelated— Having towers, like a battlement Cryptobiotic— Life habits which involve remaining hidden, as underground, under debris or in other ways Deal ated— Without wings. In ants, females that have removed their wings after the mating flight but before colony foundation Decl ivity— The inclined posterior surface of the propodeum Excised— Cut out, posterior border of the head is concave Funiculus— Segmented part of the antenna extending from the end of the scape to the tip of the antennal club Gaster— That portion of the abdomen, in Solenopsis behind the postpetiole Infuscation— An area darkened or tinged with brown or black Lestobiotic— A relationship in which a small ant species nests near a larger ant species and robs the larger ants of their brood or food supplies Mayrian furrows— Y-shaped mesonotal furrows in males of primitive ants Myrmecophile— An animal that spends at least part of its life cycle in an ant colony Occipital border— The posterior or hind margin of the head Phragmosis— The head or posterior of the abdomen, often in the soldier caste, is truncated to serve as a living plug for a nest entrance Piligerous puncture— A depression in the exoskeleton in which a hair grows 102

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103 Polymorphic— Having more than one form, said of ants with more than one worker caste such as majors, minors or soldiers Polygynous— The presence in one colony of two or more egg-laying queens Scape--The rigid antennal section which arises from the head and articulates with the funiculus Stratified— Not random, selected on the basis of previously gathered data Tumulus— A mound of soil constructed at the entrance of an ant nest and often characteristic of the species

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APPENDIX Table 1. Preferred habitats and nest sites of S. (D.) moles ta State Habitat Nest Location Reference Arizona Desert shrub community Arkansas Cotton fields, many loca-les Colorado 5,600-6,500 ft, short grass prairie, pinyon-cedar, oak woods, in clay Idaho ^. molesta Aqropyron repens & L niqer Salsole pestifer communities Illinois Dry or wet areas Louisiana Pastures Michigan High fields, old fields, rocky beach Montana Grasslands N. Carolina 17 habitats of field and forest N. Dakota Mostly grasslands New Jersey Open sunny woods, clearings, woods borders New York Open grass, gardens Ohio Woods and fields S. Carolina Pine plantation, oak pine, hardwood hammock, old field Tennessee Mostly dry grassy areas; dense shade & open areas, except mtn peaks, prefer open, dry Utah Foothills, lower mtn slopes Virginia? 3,500-5,500 ft W. Virginia Apple orchards Under rocks Chew, 1977; Hunt, 1975 Whitcomb et al., 1972; Warren & Rouse, 1969 Gregg, 1963 Moist areas, Cole, 1933, 1936 under flat rocks Grass, mounds, under stones, debris beneath bee combs Under rocks Under stones or cover in ground Under stones Rotten wood, under stones Logs, stumps, soil Amstutz, 1943 Frison, 1926 Howard & Oliver, 1979 Talbot, 1953, 1965; Gaige, 1914; Gregg, 1972 Borchert & Anderson, 1973 Carter, 1962a and 1962b Wheeler & Wheeler, 1963 Wheeler, 1905a Davis & Bequaert, 1922; Fitch, 1856 Wesson & Wesson, 1940 Van Pelt, 1966 Beneath stones, Cole, 1940; Dennis, wood Under fairly large stones In soil under rocks Compacted soil in & near roads, under roots 1938 Grundmann & Peterson, 1953; Cole, 1942 Van Pelt, 1963 Jaynes & Marucci 1947 104

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LITERATURE CITED Amstutz, M.E. 1943. The ants of the Kildeer Plain area of Ohio. Ohio J. Sci. 43:165-173. Ayre, G.L. 1963. Laboratory studies on the feeding habits of seven species of ants (Hymenoptera: Formic idae) in Ontario. Can. Entomol. 95:712-715. Back, E.A. 1937. House ants. USDA Leaflet 147:1-8. Baroni-Urbani C. 1968. Ueber die eigenartige Morphologie der mannlichen Genital ien des Genus Diplorhoptrum Mayr (Hymenoptera: Formicidae) und die taxonomischen Schlussfolgerungen. Z. Morph. Okol. Tiere 63:63. Beal F.E.L. 1911. Food of the woodpeckers of the United States. USDA Biol Surv. Bull 37:1-64. Beal, F.E.L. 1912. Food of our more important flychatchers. USDA Biol Surv. Bull 44:1-66. Bhatkar, A. and W.H. Whitcomb. 1970. Artificial diet for raising various species of ants. Florida Entomol. 53:229-232. Blum, M.S. and T.H. Jones. 1980. Alkaloidal venom mace: Offensive use by a thief ant. Naturwissenschaften 67:144. Borchert, H.F. and N.L. Anderson. 1973. The ants of the Bearpaw Mountains of Montana (Hymenoptera : Formicidae) J. Kansas Entomol. Soc. 46:200-224. Brooks, F.E. 1906. The grape curculio. West Virginia Agr. Exp. Sta. Bull. 100:213-249. Brooks, F.E. 1910. Snout beetles that injure nuts. West Virginia Agr. Exp. Sta. Bull. 128:145-185. Brooks, F.E. and E.B. Blakeslee. 1915. Studies of the codling moth in the central Appalachian region. USDA Agr. Bull. 189:1-49. Brown, W.L. 1962. A new ant of the genus Epitritus from south of the Sahara. Psyche 69:77-80. Brown, W.L. 1974. A supplement to the revision of the ant genus Basiceros (Hymenoptera.-Formicidae). J. New York Entomol. Soc. 82:131-140. 105

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106 Brown, W.L. 1977. An aberrant new genus of Myrmicine ant from Madagascar. Psyche 84:218-224. Brown, W.L. and W.W. Kempf. 1967. Tatuidris a remarkable new genus of Formicidae (Hymenoptera) Psyche 74:183-190. Browne, J.T. and R.E. Gregg. 1969. A study of the ecological distribution of ants in Gregory Canyon, Boulder, Colorado. Univ. of Colorado Studies, Series in Biol. 30:1-48. Brues, C.T. 1903. Descriptions of new ant-like and myrmecophilous Hymenoptera. Trans. Amer. Entomol Soc. 29:119-128. Bryson, H.R. 1941. The occurrence in Kansas of the sugar-cane rootstock weevil, Anacentrinus deplantus Csy. (Coleoptera,Curculionidae). J. Kansas Entomol. Soc. 14:84-90. Buckley, S.B. 1866. North American Formicidae. Proc. Entomol. Soc. Philadelphia 7:335-350. Buren, W.F., M.A. Naves, and T.C. Carlysle. 1977. False Phragmosis and apparent specialization for subterranean warfare in Pheidole lamia Wheeler (Hymenoptera : Formicidae) J. Georgia Entomol. Soc. 12:100-108. Burkhardt, C.C. 1959. Increasing sorghum stands in field tests by controlling thief ants and other insect pests. J. Econ. Entomol. 52:365-368. Carter, W.G. 1962a. Ants of the North Carolina Piedmont. J. Elisha Mitchell Sci. Soc. 78:1-18. Carter, W.G. 1962b. Ant distribution in North Carolina. J. Elisha Mitchell Sci. Soc. 78:150-204. Chew, R.M. 1977. Some ecological characteristics of the ants of a desert-shrub community in southeastern Arizona. Amer. Midland Natur. 98:33-49. Cole, A.C., Jr. 1933. Ant communities of a section of the sagebrush semi-desert in Idaho, with special reference to the vegetation (Hymenop. :Formicidae) Entomol. News 44:16-19. Cole, A.C., Jr. 1936. An annotated list of the ants of Idaho (Hymenoptera:Formicidae). Can. Entomol. 68:34-39. Cole, A.C., Jr. 1940. A guide to the ants of the Great Smoky Mountains National Park, Tennessee. Amer. Midland Natur. 24:1-88. Cole, A.C., Jr. 1942. The ants of Utah. Amer. Midland Nat. 28: 358-388. Collins, H.L. and G.P. Markin. 1971. Inquilines and other arthropods collected from nests of the Imported Fire Ant Solenopsis saevissima richteri Ann. Entomol. Soc. Amer. 64:1376-1380.

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107 Cook, T.W. 1953. The ants of California. Pacific Books, Palo Alto. 462 p. Creighton, W.S. 1930. The new world species of the genus Solenopsis (Hymenop. Formicidae) Proc. Amer. Acad. Arts Sci 66:39-151. Creighton, W.S. 1950. The ants of North America. Bull. Mus. Comp. Zool. 104:1-585. Davis, W.T. and J. Bequaert. 1922. An annotated list of the ants of Staten Island and Long Island, N.Y. Bull. Brooklyn Entomol Soc. 17:1-25. Dennis, C.A. 1938. The distribution of ant species in Tennessee with reference to ecological factors. Ann. Entomol. Soc. Amer. 31: 267-308. Eckert, J.E. and A. Mallis. 1937. Ants and their control in California California Agr. Exp. Sta. Circ. 342:1-39. Emery, C. 1895. Beitrage zur kenntniss der nordamerikanischen Ameisenfauna. Zob'l Jahrb., Abt. f. System. 8:257-360. Esser, R.P. 1973. A four. minute lactophenol fixation method for nematodes. Plant Dis. Rep. 57:1045-1046. Ettershank, G. 1966. A generic revision of the world myrmicinae related to Solenopsis and Pheidologeton (Hymenoptera : Formicidae ) Australian J. Zool. 14:73-171. Fall, H.C. 1928. Alaudes Pan-Pacific Entomol. 4:145-150. Felt, E.P. 1916. Thirtieth report of the state entomologist. New York State Mus. Bull. 180:10, 68-69. Fitch, A. 1856. First and second report on the noxious, beneficial and other insects of the state of New York. 336 p. Forbes, S.A. 1896. Insect injuries to the seed and root of Indian corn. Illinois Agr. Exp. Sta. Bull. 44:209-296. Forbes, S.A. 1920. A monograph of insect injuries to Indian corn. Eighteenth Rept. State Entomol. Illinois. 149 p. Forel A. 1901. Varietes Myrmgcologiques Ann. Soc. Entomol. Belg. 45:334-382. Frison, T.H. 1926. Contributions to the knowledge of the interrelations of the bumblebees of Illinois with their animate environment. Ann. Entomol. Soc. Amer. 19:203-235. Gaige, F.M. 1914. Results of the Mershon Expedition to the Charity Islands, Lake Huron. The Formicidae of Charity Island. Occasional papers of Mus. of Zool., Univ. of Michigan 5:1-29.

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103 Gotwald, W.H. 1969. Comparative morphological studies of the ants, with particular reference to the mouthparts (Hymenoptera:Formicidae) Cornell Univ. Agr. Exp. Sta. Memoir 408:1-150. Gregg, R.E. 1963. The ants of Colorado. Univ. of Colorado Press, Boulder. 792 p. Gregg, R.E. 1972. The northward distribution of ants in North America. Can. Entomol. 104:1073-1091. Gross, H.R. and W.T. Spink. 1969. Responses of striped earwigs following applications of Heptachlor and Mirex, and predator-prey relationships between imported fire ants and striped earwigs. J. Econ. Entomol. 62:686-689. Grundmann, A.W. and B.V. Peterson. 1953. House infesting ants in Salt Lake City, Utah. J. Kansas Entomol. Soc. 26:59-60. Hayes, W.P. 1920. Solenopsis molesta Say (Hym.): A biological study. Kansas Agr. Exp. Sta. Tech. Bull. 7:1-55. Hayes, W.P. 1925. A preliminary list of the ants of Kansas (Hymenoptera Formicidae). Entomol. News 36:39-43. Headlee, T.J. and J.W. McColloch. 1913. The chinch bug. Kansas Agr. Exp. Sta. Bull. 191:287-353. Herrick, G.W. 1921. Insects injurious to the household and annoying to man. Macmillan Co., New York. 470 p. Holldobler, B. 1973. Chemische Strategie beim Nahrungserwerb der Diebsameise ( Solenopsis fugax Latr.) und der Pharoameise ( Monomorium pharoanis L.). Qecologia (Berl.) 11:371-380. Howard, F.W. and A.D. Oliver. 1979. Field observations of ants (Hymenoptera: Formicidae) associated with red imported fire ants, Solenopsis invicta Buren, in Louisiana pastures. J. Georgia Entomol. Soc. 14:159-163. Huddleston, E.W. and S.S. Fluker. 1968. Distribution of ant species of Hawaii. Proc, Hawaiian Entomol. Soc. 20:45-69. Hung, A.C. 1974. Ants recovered from refuse pile of the Pyramid Ant Conomyrma insana (Buckley) ( Hymenoptera : Formi ci dae ) Ann. Entomol. Soc. Amer. 67:522-523. Hunt, J.H. 1975. A checklist of the ants of Arizona. J. Arizona Acad. Sci. 10:20-23. Hunter, W.D. and W.D. Pierce. 1912. Mexican cotton boll weevil. USDA Bur. Entomol. Bull. 144:1-188.

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109 Hunter, W.D. and W.E. Hinds. 1904. The Mexican cotton boll weevil. USDA Div. Entomol. Bull. 45:1-116. Jaynes, H.A. and P.E. Marucci. 1947. Effect of artificial control practices on the parasites and predators of the codling moth. J. Econ. Entomol. 40:9-25. Jenne, E.L. 1909. The codling moth in the Ozarks. USDA Bur. Entomol. Bull. 80:1-32. Jones, T.H. 1980. (5Z-8E)-3-heptyl -5-methyl pyrrol izidine from a thief ant. (Submitted). Jones, T.H., M.S. Blum, and H.M. Fales. 1979. Synthesis of unsymmetrical 2 ,5-DI-n-al kyl pyrrol idi nes : 2-hexyl -5-pentyl pyrrol idi ne from the thief ants Solenopsis molesta S. texana and its homologues. Tetrahedron Letters 12:1031-1034. Jones, T.H., M.S. Blum, H.M. Fales, and C.R. Thompson. (5Z,8E)-3heptyl -5-methyl pyrrol izidine from a thief ant. (In press). Judd, S.D. 1901. The relation of sparrows to agriculture. USDA Biol Surv. Bull 15:1-98. Kennedy, C.H. 1938. Solenopsis rosella Kennedy, a new ant from Southern Ontario. Can. Entomol. 70:232-236. King, G.B. 1895. The study of the Formicidae of Lawrence, Mass. Entomol. News 6:220-223. King, G.B. 1896. Mixed colonies of ants. Entomol. News 7:167-170. King, G.B. 1897. Some ants and myrmecophi lous insects from Toronto. Can. Entomol. 29:100-103. King, G.B. 1901a. A check-list of the Massachusetts Formicidae with some notes on the species. Psyche 9:260-262. King, G.B. 1901b. Some new records of the New England Formicidae. Psyche 9:270-271. Landis, B.J. 1967. Attendance of Smynthurodes betae (Homoptera: Aphidae) by Solenopsis molesta and Tetramorium caespitum (Hymenoptera :FormicidaeT Ann. Entomol. Soc. Amer. 60:707. Leston, D. 1973. The ant mosaic-tropical tree crops and the limiting of pests and diseases. Pans 19:311-341. MacConnell, J.G., M.S. Blum, W.F. Buren, R.N. Williams, and H.M. Fales. 1976. Fire ant venoms: Chemotaxonomic correlations with alkaloidal compositions. Toxicon 14:69-78. Macnamara, C. 1945. A note on the swarming of Solenopsis molesta Say (Hymenoptera) Can. Entomol. 77:40.

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no Majer, J.D. 1972. Ant mosaic in Ghana cocoa farms. Bull. Entomol Res. 62:151-160. Mallis, A. 1941. A list of the ants of California with notes on their habits and distribution. Bull. Southern California Acad. Sci. 40:61-100. Mann, W.M. 1911a, Notes on the guests of some Californian ants. Psyche 18:27-31. Mann, W.M. 1911b. On some northwestern ants and their guests. Psyche 18:102-109. Markin, G.P., J. O'Neal, and H.L. Collins. 1974. Effects of Mirex on the general ant fauna of a treated area in Louisiana. Environmental Entomol. 3:895-898. Mayr, G. 1855. Zoologisch-Botanische Gesellscheft. Wien, Verhandl 5:449-450. Mayr, G. 1886. Die formiciden der Vereinigten Staaten von Nordamerika. Zoologisch-Botanische Gesellschaft. Wien, Verhandl. 36:419-464. Mitchell, J.D. and W.D. Pierce. 1912. The ants of Victoria County, Texas. Proc. Entomol. Soc. Wash. 14:67-76. McColloch, J.W. and W.P. Hayes. 1916. A preliminary report on the life economy of Solenopsis molesta Say. J. Econ. Entomol. 9: 23-38. Nielsson, R.J., A. P. Bhatkar, and H.A. Denmark. 1971. A preliminary list of the ants associated with aphids in Florida. Florida Entomol. 54:245-248. O'Neal, J. 1974. Predatory behavior exhibited by three species of ants on the imported fire ants: Solenopsis invicta Buren and Solenopsis richteri Fore! Ann. Entomol. Soc. Amer. 67:1. Pierce, W.D. 1912. The insect enemies of the cotton boll weevil. USDA Bur. Entomol. Bull. 100. Rees, D.M. and A.W. Grundmann. 1940. A preliminary list of the ants of Utah. Bull. Univ. of Utah 31:1-12. Robbins, W.W. 1910. An introduction to the study of the ants of northern Colorado. Univ. Colorado Studies 7:215-222. Ross, H.H., G.L. Rotramel and W.E. Laberge. 1971. A synopsis of common and economic Illinois ants, with keys to the genera (Hymenoptera, Formicidae). Illinois Natur. Hist. Surv. Biol. Notes 71:1-22.

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m. Say, T. 1836. Descriptions of new species of North American Hymenoptera, and observations on some already described. Boston J. Natur. Hist. 1:210-305. Schoene, W.J. 1916. The cabbage maggot: Its biology and control. New York Agr. Exp. Sta. Bull. 419:99-160. Schumacher, A. and W.G. Whitford. 1976. Spatial and temporal variation in Chihuahuan desert ant faunas. Southwestern Natur. 21: 1-8. Schwarz, E.A. 1890a. Myrmecophilous Coleoptera found in temperate North America. Proc. Entomol Soc. Washington 1:237-241. Schwarz, E.A. 1890b. Revised list of North American mymecophilous Coleoptera. Proc. Entomol. Soc. Washington 1:241-247. Schwarz, E.A. 1896. Additions to the lists of North American termitophilous and myrmecophilous Coleoptera. Proc. Entomol. Soc. Washington 3:73-77. Smith, D.R. 1979. Superfamily Formicoidea. J_n Krombein, K.V., P.D. Hurd, Jr., D.R. Smith, and D.B. Burks (eds.), Catalog of Hymenoptera in America north of Mexico. Synoptic Catalogue (Agric. Monogr. 2), GP0, Washington, pp. 778-875. Smith, M.R. 1930. A list of Florida ants. Florida Entomol. 14:1-6. Smith, M.R. 1931. An additional annotated list of the ants of Mississippi (Hymenoptera : Formicoidea ) Entomol. News 42:16-24. Smith, M.R. 1942. A new North American Solenopsis ( Diplorhoptrum ) (Hymenoptera : Formic idae) Proc. Entomol. Soc. Washington 44: 209-211. Smith, M.R. 1943. A generic and subgeneric synopsis of the male ants of the United States. Amer. Midland Natur. 30:273-321. Smith, M.R. 1944. Additional ants recorded from Florida, with descriptions of two new subspecies. Florida Entomol. 27:14-17. Smith, M.R. 1947. A generic and subgeneric synopsis of the United States ants, based on the workers (Hymenoptera :Formicidae) Amer. Midland Natur. 37:521-647. Smith, M.R. 1965. House-infesting ants of the eastern United States. USDA Tech. Bull 1326:1-105. Smith, M.R. and W.A. Morrison. 1916. South Carolina ants (Hym.). Entomol News 27:110-111

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112 Smythe, R.V. and H.C. Coppel 1973. The eastern subterranean termite Reticul itermes flavipes (Kollar), and the common thief ant, Solenopsis molesta (Say), in the laboratory, with notes on other associated ant species. Trans. Wisconsin Acad. Sci. Arts Letters 61 : 95-1 02. Srivastava, B.K. and H.R. Bryson. 1956. Insecticidal seed treatment for control of the thief ant. J. Econ. Entomol 49:329-333. Talbot, M. 1953. Ants of an old-field community on the Edwin S. George Reserve, Livingston County, Michigan. Contrib. Lab. Vertebrate Biol. Univ. Michigan 63:1-13. Talbot, M. 1965. Populations of ants in a low field. Insectes Sociaux 12:19-48. Talbot, M. 1975. A list of the ants (Hymenoptera:Formicidae) of the Edwin S. George Reserve, Livingston County, Michigan. Great Lakes Entomol. 8:245-246. Thorn, G. 1935. Notes on free-living and plant parasitic nematodes. 4. A new slide ring material. Proc. Helmintho. Soc. Wash. 2:98. Van Pelt, A. 1963. High altitude ants of the Southern Blue Ridge. Amer. Midland Natur. 69:205-223. Van Pelt, A.F. 1947. A preliminary key to the worker ants of Alachua County, Florida. Florida Entomol. 30:57-67. Van Pelt, A.F. 1966. Activity and density of old-field ants of the Savannah River Plant, South Carolina. J. Elisha Mitchell Sci. Soc. 82:35-43. Van Pelt, A.F., Jr. 1958. The ecology of the ants of the Welaka Reserve, Florida (Hymenoptera:Formicidae). Part II. Annotated list. Amer. Midland Natur. 59:1-57. Warren, L.O. and E.P. Rouse. 1969. The ants of Arkansas. Arkansas Agr. Exp. Sta. Bull. 742:1-67. Webster, F.M. 1893. Insects affecting the blackberry and raspberry. Ohio Agr. Exp. Sta. Bull. 45:151-217. Wesson, L.G., Jr., and R.G. Wesson. 1940. A collection of ants from south central Ohio. Amer. Midland Natur. 21:89-103. Wheeler, G.C. and J. Wheeler. 1955. The ant larvae of the Myrmicine tribe Solenopsidini Amer. Midland Natur. 54:119-141. Wheeler, G.C. and J. Wheeler. 1960. Supplementary studies on the larvae of the Myrmicinae. Proc. Entomol. Soc. Wash. 62:1-32. Wheeler, G.C. and J. Wheeler. 1963. The ants of North Dakota. Univ. of North Dakota Press, Grand Forks. 326 p.

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113 Wheeler, W.M. 1901. The compound and mixed nests of American ants. Amer. Natur. 35(Part II) :513-539. Wheeler, W.M. 1904a. Ants from Catalina Island, California. Bull. Amer. Mus. Natur. Hist. 20:269-271. Wheeler, W.M. 1904b. The ants of North Carolina. Bull. Amer. Mus. Natur. Hist. 20:299-306. Wheeler, W.M. 1905a. An annotated list of the ants of New Jersey. Bull. Amer. Mus. Natur. Hist. 21:371-403. Wheeler, W.M. 1905b. Ants from Catalina Island, Cal Bull. Southern California Acad. Sci 4:60-63. Wheeler, W.M. 1908. The ants of Texas, New Mexico and Arizona. Bull. Amer. Mus. Natur. Hist. 24:399-485. Wheeler, W.M. 1910. Ants: Their structure, development and behavior. Columbia Univ. Press, New York. 663 p. Wheeler, W.M. 1913. The ants of Cuba. Bull. Mus. Comp. Zool 54: 477-505. Wheeler, W.M. 1915. Additions to the ant-fauna of North America. Bull. Amer. Mus. Natur. Hist. 34:389-421. Wheeler, W.M. 1916. Jjn H.L. Viereck (ed.), The Hymenoptera, or wasplike insects of Connecticut. State Geol Nat. Hist. Surv. Bull. 22:1-824. Wheeler, W.M. 1932. A list of the ants of Florida with descriptions of new forms. J. New York Entomol Soc. 40:1-17. Whitcomb, W.H. and K. Bell. 1964. Predaceous insects, spiders and mites of Arkansas cotton fields. Univ. Arkansas Agr. Exp. Sta. Bull. 690:1-84. Whitcomb, W.H., H.A. Denmark, A. P. Bhatkar, and G.L. Greene. 1972. Preliminary studies of the ants of Florida soybean fields. Florida Entomol. 55:129-142. White, R.T. 1940. The relation of ants to the Japanese beetle and its established parasites. J. New York Entomol. Soc. 48:85-99. Wickham, H.F. 1892. Notes on some myrmecophilous Coleoptera. Psyche 6:321-323. Wickham, H.F. 1894. Further notes on Coleoptera found with ants. Psyche 7:79-81. Wilson, E.0. 1964. The ants of the Florida Keys. Breviora 210:1-14.

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114 Wilson, E.O. 1971. The insect societies. Belknap Press of Harvard Univ. Press, Cambridge, Mass. 548 p. Wilson, E.O. 1975. Enemy specification in the alarm-recruitment system of an ant. Sci. 190:798-800. Wing, M.W. 1951. A new genus and species of myrmecophilous Diapriidae with taxonomic and biological notes on related forms. Trans. Roy. Entomol. Soc. London 102:195-210. Wolcott, G.N. 1948. The ants of Puerto Rico. J. of Agr. of Univ. Puerto Rico 32:749-975. Yensen, N.P. and W.H. Clark. 1977. A checklist of Idaho ants (Hymenoptera:Formicidae) Pan Pacific Entomol. 53:181-187. Young, J. and D.E. Howell. 1964. Ants of Oklahoma. Oklahoma Univ. Exp. Sta. Misc. Pub. 71:1-42.

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BIOGRAPHICAL SKETCH Catherine R. Thompson was born November 21, 1952, in Boston, Massachusetts. Her family moved to Cedar Falls, Iowa, where she attended Malcolm Price Laboratory School. In June, 1971, she graduated from Northern University High School in Cedar Falls. She attended the University of Northern Iowa in Cedar Falls, during the summers of 1971, 1972, 1973 and the fall of 1973. She attended Cornell College during the remainder of 1971, 1972, 1973 and part of 1974, graduating in June, 1974, with a B.A. in biology and Engl ish. In September, 1974, she entered graduate shcool in the Department of Entomology and Nematology at the University of Florida. She received the M.S. degree in June, 1976, and commenced work'toward the Doctor of Philosophy degree in entomology and a minor in botany at the University of Florida. 115

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I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for r ne deqree of Doctor of Philosophy. Dr. William F. Buren, Chairman ~^ Professor of Entomology and Nenvitologv I certify that I have read this study and that in nv ooinion it conforms to acceptable standards of scholarly presentation' and is fully adequate, in scope and quality, as a dissertation fcr the deqree of Doctor of Philsophy. L //. / / ..Lj... Drf. Dana G". Griffirf III Professor of Botany/ I certify that I have read this study and that in my opinion it conrorms to acceptable standards of scholarly presentation and is fully adequate, m scope and quality, as a dissertation for the deqree of Doctor of Philsophy. Dr. Reece I. Sailer Graduate Research Professor of Entomology and Hematology

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This dissertation was submitted to the Graduate Faculty of the College of Agriculture and to the Graduate Council, and was accepted as partial fulfillment of the requirements for the degree of Doctor of Philosophy. August, 1980 in ^College of Agric^tui Dean, Graduate School


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650'
640
en
c
r
£ 630
O
E
O 620
OI
E
610
550
540-1
F=Field flight
B=Beginning of field flight
E=End of field flight
wF=Woods flight
wE=End of woods flight
*-~-=Sunri se
{wf
I I I I I I I I I I I I I I I I I I I I 1 I I I I I I I I I I 1 I 1 I I I I I I I -L 1 1 I 1--It I II 1 I I I I III I L 1 I -I
26 30 4 8 12 16 20 24 28 1 5 9 13 17 21 25 29
June
July
August
Date (1979)
Figure 46. Correlation of (j).) pergandei mating flights with times of sunrise in Gainesville,
Florida.


87
possible nest numbers and territorial boundaries were constructed.
(£.) carolinensis was the dominant species in both habitats while
(]).) abdita was common, particularily in the field. Of the less
conmon species, (ID.) xenovenenum was more often found in the woods,
_S. (]).) nickersoni was rare in both habitats and S^. (]).) pergandei was
only in the woods site. This was a beginning study of previously
unknown or poorly known species. From the preliminary data no habitat
preferences for the various species should be inferred at this time.


93
Initially I hypothesized that mated females were accepted by
existent colonies after a flight. Nests near the flight study area
contained as many as 20-30 deal ate females which I thought were
reproducing queens. Observation of nests which had initiated mating
flights for several weeks gave another explanation: females were
observed with three wings, two wings, one wing and no wings at all
during flights. These females, even those with no wings at all, behaved
exactly as though they had wings and could take flight. When it became
light, and those females with wings had flown, these females retreated
back down the nest entrances. Apparently they repeated this behavior
flight after flight, progressing from four wings to no wings at all.
The wings of female ants have lines of weakness along which they
normally break off after the female has gone on the mating flight. I
suspect that jostling in the crowded nest caused some wing breakage and
that the loss of one wing was enough to prevent flight. It was these
unfortunate females who slowly lost all their wings. I was unable to
determine the final fate of these females. It is unlikely any were
mated since a nest contained only one sex, and I did not observe males
near any tumulus containing females.
By 8 a.m. S^. (CL) pergandei females could be found at a second
study site: a USDA light trap at the Insects Affecting Man and Animals
Laboratory in Gainesville. If rainwater was standing on the trap roof,
large numbers of the males often were caught by their wings in the water
film, but few ever entered the trap. When rain did not fall for
several days, large flights took place. For example, rain occurred on
June 30, 1980, after a dry week. The light trap the following morning
contained 2,081 S_. (CL) pergandei alate females, 5 males and 83 dealated


114
Wilson, E.O. 1971. The insect societies. Belknap Press of Harvard
Univ. Press, Cambridge, Mass. 548 p.
Wilson, E.O. 1975. Enemy specification in the alarm-recruitment
system of an ant. Sci. 190:798-800.
Wing, M.W. 1951. A new genus and species of myrmecophilous Diapriidae
with taxonomic and biological notes on related forms. Trans. Roy.
Entomol. Soc. London 102:195-210.
Wolcott, G.N. 1948. The ants of Puerto Rico. J. of Agr. of Univ.
Puerto Rico 32:749-975.
Yensen, N.P. and W.H. Clark. 1977. A checklist of Idaho ants
(Hymenoptera:Formicidae). Pan Pacific Entomol. 53:181-187.
Young, J. and D.E. Howell. 1964. Ants of Oklahoma. Oklahoma Univ.
Exp. Sta. Mise. Pub. 71:1-42.


52
Types:
Holotypea worker collected by Naves trap on June 16, 1979, by
C. R. Thompson. Paratypes are numerous workers taken in Naves traps
June to October, 1979.
The holotype and several paratypes will be deposited at the
Museum of Comparative Zoology. Paratypes will also be deposited in
the Florida State Collection of Arthropods, Gainesville, Florida.
Discussion:
This species is so named because it was found by Dr. Tappey Jones
(Univ. of Georgia) to have (5Z,8E)-3-heptyl-5-methyl pyrrolizidine as
the main constituent of its venom. This compound is new to biology.
The species is common throughout the state in many habitats.
Males and females have been observed in an afternoon flight at
Homestead, Florida, in July, 1964. Males have been taken from a spider
web in Gainesville, Florida, on July 30, 1978, and from a light trap in
Miami Beach (June 3, 1947). This is the smallest Diplorhoptrum species
in the United States and has been taken from under stones, unlike most
other species of the subgenus in Florida.


19
S. (D.) molesta and S. (D.) texana to forage above ground during the
day. (D_.) texana was observed in a late morning expedition to food
in a car trunk (July, 1980) at Clinton, Iowa (pers. comm., Dr. W. F.
Burn) while I have taken S_. (_D.) texana at honey baits in full sun
(June, 1980) at Cedar Falls, Iowa.
Two materials often used to maintain ant nest humidity are plaster
of paris and Castone When colonies were placed in petri dishes with
floors of either compound, workers began to go into convulsions within
a few hours, then died. An entire 5L (2-) carol inensis colony died
overnight June 3, 1980, while a IS. (_D.) pergandei colony displayed
similar symptoms the following day. The queen died two days after
exposure to these compounds, or possibly because of shock due to colony
loss. Neither species queen showed convulsive symptoms.
Colony nest humidity was finally maintained by 1) moistened cotton
floors, or 2) by using "aged" plaster of paris covering only one fourth
of the nest floor. The aged plaster was in old petri dish nests which
had been used and repeatedly washed in hot, soapy water.
The small size of the Diplorhoptrum workers allows them to escape
from any kind of petri dish. Talc and Fluon could not be used because
of the high humidity levels. When colonies were sealed in with artist's
clay, the workers gnawed 0.82 mm holes through the clay and escaped.
In colonies sealed with vaseline, many workers died overnight, ap
parently from fumes given off by this material. Finally the vegetable
fat Crisco was tried. The ants refused to cross the greasy barrier.

Crisco was subsequently placed around the inside rims of petri dishes
effectively preventing ant escapes.


18
put in vials, and red marker yarn placed in the soil to mark the bait
station until it was rebaited.
Use of Light Trap Collections
During May through August, Diplorhoptrum males and females of
S.. (2-) pergandei, (£.) carolinensis, and rarely (£.) reinerti
are attracted to light traps. Larger collections of S^. (EL)
carolinensis can be made with a light trap and a white sheet than
with a conventional, walk-in light trap. The reason for this is
unknown, but possibly a different quality of ultraviolet light is
reflected by the sheet, and thus attracts this species.
Laboratory Studies
Colony Nest Materials
Maintaining Diplorhoptrum colonies in the laboratory is extremely
difficult. Their small size and hypogaeic habits make them highly
vulnerable to desiccation. Workers of colonies in open laboratory pans
at 80% relative humidity die within 24 hours. If a colony is presented
with a moist chamber within an open laboratory pan, the workers which
forage outside the chamber will die in the open pan before they find
their way back to the colony. The colony dies by slow loss of
foraging workers.
Florida Diplorhoptrum species seem to need humidity levels of
nearly 100%, in contrast to SL (j).) molesta, and other Diplorhoptrum
species such as the unidentified Peruvian species in Dr. Ed Wilson's
laboratory at Harvard University. This species is kept in a plastic
box open to the air. Lower humidity requirements apparently allow


Ill
Say, T. 1836. Descriptions of new species of North American
Hymenoptera, and observations on some already described.
Boston J. Natur. Hist. 1:210-305.
Schoene, W.J. 1916. The cabbage maggot: Its biology and control.
New York Agr. Exp. Sta. Bull. 419:99-160.
Schumacher, A. and W.G. Whitford. 1976. Spatial and temporal varia
tion in Chihuahuan desert ant faunas. Southwestern Natur. 21:
1-8.
Schwarz, E.A. 1890a. Myrmecophilous Coleptera found in temperate
North America. Proc. Entomol. Soc. Washington 1:237-241.
Schwarz, E.A. 1890b. Revised list of North American mymecophilous
Coleptera. Proc. Entomol. Soc. Washington 1:241-247.
Schwarz, E.A. 1896. Additions to the lists of North American termito-
philous and myrmecophilous Coleptera. Proc. Entomol. Soc.
Washington 3:73-77.
Smith, D.R. 1979. Superfamily Formicoidea. In Krombein, K.V., P.D.
Hurd, Jr., D.R. Smith, and D.B. Burks (eds.), Catalog of Hymenoptera
in America north of Mexico. Synoptic Catalogue (Agrie. Monogr. 2),
GP0, Washington, pp. 778-875.
Smith, M.R. 1930. A list of Florida ants. Florida Entomol. 14:1-6.
Smith, M.R. 1931. An additional annotated list of the ants of
Mississippi (Hymenoptera:Formicoidea). Entomol. News 42:16-24.
Smith, M.R. 1942. A new North American Solenopsis (Diplorhoptrum)
(Hymenoptera:Formicidae). Proc. Entomol. Soc. Washington 44:
209-211.
Smith, M.R. 1943. A generic and subgeneric synopsis of the male ants
of the United States. Amer. Midland Natur. 30:273-321.
Smith, M.R. 1944. Additional ants recorded from Florida, with de
scriptions of two new subspecies. Florida Entomol. 27:14-17.
Smith, M.R. 1947. A generic and subgeneric synopsis of the United
States ants, based on the workers (Hymenoptera:Formicidae).
Amer. Midland Natur. 37:521-647.
Smith, M.R. 1965. House-infesting ants of the eastern United States.
USDA Tech. Bull. 1326:1-105.
Smith, M.R. and W.A. Morrison. 1916. South Carolina ants (Hym.).
Entomol. News 27:110-111.


47
10. Solenopsis (Diplorhoptrum) texana Emery
Solenopsis pollux var. texana Emery, 1895. Zoo! Jahrb., Abt. f.
System. 8:278.
Solenopsis texana Fore!, 1901. Ann. Soc. Entomol. Belg. 45:345.
Solenopsis rosella Kennedy, 1938. Can. Entomol. 70:232.
Solenopsis (Diplorhoptrum) texana Creighton, 1950. Bull.
Mus. Comp. Zool. 104:238.
Type locality: Texas
Types: Museo Civico di Storia Naturale "Giacomo Doria", Genoa, Italy.
A questionable series is at the Museum of Comparative Zoology at
Harvard.
Range: Central Texas and southeastern states north to Canada
Diagnosis:
Similar to molesta, but head more slender, thorax distinctly more
slender. Postpetiole a little wider than the petiole seen from above.
Hairs sparse and of mixed lengths. No piligerous punctures. Head and
gaster often weakly infuscated.
_S. (JL) texana is larger than carolinensis and the hair patterns
are different. The small females with the very large eyes seem to be
unique to carolinensis.
Discussion:
I have not been able to find this species in Florida. Although
Krombein et al. (1971) list this species from Florida, I suspect exam
ination of the specimens would show them to be carolinensis. Authentic
specimens of S.. (D.) texana may eventually be found in the state.


94
females. Before I arrived, however, a number of these ants had already
been carried off by foraging Pheidole workers. Although held in the
laboratory several days, no further females shed their wings.
It seemed probable that large numbers of these females were mated,
particularity since rain afta a dry period would have coordinated a
number of colony flights. Examination of 20 dealated and 20 alate S_.
(_D.) pergandei females by Adrian Glover (USDA Fire Ant technician)
revealed that all the dealated females but only two of the alates were
mated. These data suggest that the 2,081 S_. (]D.) pergandei females
captured June 30, 1980, were mostly unmated. More information is needed
to resolve this question.
Twenty alate S. (£.) pergandei females in groups of five from the
light trap were placed on the ground and observed for 15 minutes. Within
seconds each female ran quickly into holes and under sticks and leaves
and took cover. When the cover was removed 15 minutes later, four
females were not found, three had begun to excavate, one had removed her
wings, and the remainder had simply remained hidden. Although this
behavior indicates females may found nests claustrally, attempts to induce
colony founding in the laboratory have not been successful.
In summary, S_. (D.) pergandei is the only subterranean Florida
Diplorhoptrum species which constructs nest structures at the soil surface.
It constructs crenelated tumuli from June through early September which
are utilized only for mating flights. These tumuli apparently allow
more sexuals to remain at the soil surface and offer a surface for flight
take-off. Nests produce only males or only females and each nest has
many flights during the summer. These flights occur before dawn, and
rain in the previous 24 hours is necessary for flight activity.


51
Sculpture: Head with scattered moderate punctures;
mesonotum with weak punctures. Pleurae of propodeum, petiole,
and postpetiole weakly striate or shagreened. All other
surfaces smooth and shining.
Pilosity: Body and appendages with numerous short hairs.
Wings with dark brown veins and stigma, membranes also com
pletely infuscated with brown.
Color: Entire body including appendages brownish to dark
brown.
Male:
Measurements: Head length 0.40 mm, head width (including
eyes) 0.50 mm, thorax length 1.08 mm, petiole length 0.34 mm,
eye length 0.19 mm, body length 2.82 mm.
Structural characters: Antennae 12-jointed, last two joints
and particularly the last joint longer than other funicular joints,
but not enlarged or clublike. Eyes occupying about one-half of
head length, ocelli 0.065 mm in diameter. Mandibles weak, each
with 2 or 3 teeth. Head trapezoidal in shape.
Thorax without Mayrian furrows on the mesonotum. Petiolar
node with slightly concave superior border.
Sculpture: Head and dorsum of thorax with weak punctures.
Propodeum sculptured with striato-punctate markings. Petiolar
node punctate.
Pilosity: All surfaces with numerous short hairs.
Color: Dark brown, including the appendages. Wing veins
and membranes completely infuscated with brown.


PLATE 6
Figure 21. Lateral view of worker of S_. (_D.) pi eta Emery
(7 OX)
Figure 22. Head of the worker of S^. (I).) pi eta Emery
(140X)
Figure 23. Petiole and postpetiole of worker of S. (JL)
pi eta Emery (378X)
Figure 24. Dorsal view of worker of S_. (D_.) pi eta Emery
(70X)


APPENDIX
Table 1.
Preferred habitats and
nest sites of
S. (D.) molesta
State
Habitat
Nest Location
Reference
Arizona
Desert shrub community

Chew, 1977; Hunt, 1975
Arkansas
Cotton fields, many locales

Whitcomb et al., 1972;
Warren & Rouse, 1969
Colorado
5,600-6,500 ft, short grass
prairie, pinyon-cedar, oak
woods, in clay
Under rocks
Gregg, 1963
Idaho
S. molesta-Aqropyron repens
& L. niqer-Salsole pestifer
communities
Moist areas,
under flat rocks
Cole, 1933, 1936
Illinois
Dry or wet areas
Grass, mounds,
under stones,
debris beneath
bee combs
Amstutz, 1943
Frison, 1926
Louisiana
Pastures

Howard & Oliver, 1979
Michigan
High fields, old fields,
rocky beach

Talbot, 1953, 1965;
Gaige, 1914;
Gregg, 1972
Montana
Grasslands
Under rocks
Borchert & Anderson, 1973
N. Carolina
17 habitats of field
and forest
Under stones or
cover in ground
Carter, 1962a and
1962b
N. Dakota
Mostly grasslands
Under stones
Wheeler & Wheeler, 1963
New Jersey
Open sunny woods, clear
ings, woods borders

Wheeler, 1905a
New York
Open grass, gardens

Davis & Bequaert, 1922;
Fitch, 1856
Ohio
Woods and fields
Rotten wood,
under stones
Wesson & Wesson, 1940
S. Carolina
Pine plantation, oak pine,
hardwood hammock, old field
Logs, stumps,
soil
Van Pelt, 1966
Tennessee
Mostly dry grassy areas;
dense shade & open areas,
except mtn peaks, prefer
open, dry
Beneath stones,
wood
Cole, 1940; Dennis,
1938
Utah
Foothills, lower mtn slopes
Under fairly
large stones
Grundmann & Peterson,
1953; Cole, 1942
Virginia?
3,500-5,500 ft
In soil, under
rocks
Van Pelt, 1963
W. Virginia
Apple orchards
Compacted soil
in & near roads,
under roots
Jaynes & Marucci, 1947
104


89
mornings following rain when flights did not occur. The ants constructed
chambers at ground level, then formed a thin roof of soil pellets with
worker-sized entrances. No flights were ever observed from these
structures.
Digging-out tumuli apparently were for exactly that purpose. Other
conditions apparently were not favorable for flights, and the ants were
most likely repairing passages which had collapsed with the rain. These
tumuli were simply piles of excavated soil deposited near the entrance.
Flight Factors
Preliminary studies in the summer of 1978 suggested that S^. (£.)
pergandei mating flights did not occur unless there had been measurable
precipitation during the previous 24 hours. Data gathered on 30 flights
from June to September of 1979, when they ceased in the Gainesville
area, showed that 83% (25) of the flights occurred following a rain.
On seven additional mornings tumuli were constructed but no flights
occurred. The ants frequently constructed closed, digging-out and a
few crenelated tumuli on non-flight mornings. This indicated that con
ditions became unfavorable during the night, or that additional stimuli
utilized by the ants to initiate flight were not favorable.
As the summer progressed, mating flights occurred slightly later
each week. In late June, flights began at 5:50 a.m. In early August,
they were beginning at ca. 6:08 a.m. This suggested that an additional
factor potentially triggering flights was light. A commercial light
meter was used to attempt light readings at flight times. It was so
dark in the half hour before dawn when these ants flew that almost no
light values were registered. Readings at 6:41 a.m., shortly after a


30
a unique head shape, shows that the species is not close to pergandei.
The punctures on the head are stronger even than in pergandei, and the
clear median streak on the head free of punctures seems to be a constant
character which does not occur in tennesseensis. The head is narrower
in proportion to length than in pergandei but is noticeably wider than
in tennesseensis. The dorsum of the thorax is more flattened in
tennesseensis than in abdita. Scape and funiculus length shorter in
abdita than in pergandei.
This species has been found at Gainesville and Tall Timbers
Research Station north of Tallahassee. It was relatively common in
the test area near Gainesville although not as abundant as
carolinensis. The species may not be rare, but merely previously
overlooked and/or unrecognized.


44
Sculpture: Head with noticeable but small punctures,
these much weaker than in pergandei, tennesseensis, abdita,
or xenovenenum n.sp. Remainder of integument smooth and
shining.
Pilosity: Head with numerous short hairs, thorax with less
numerous, somewhat longer hairs.
Color: Pale yellow or very pale brown, the integument
largely transparent.
Female:
Measurements: Head length 0.54 mm, head width 0.54 0.002 mm,
head index 100, scape length 0.40 mm, funiculus length 0.52 mm,
scape index 74, body length 2.7 mm.
Structural characters: Head as long as broad with convex
sides and straight or very slightly concave posterior border.
Clypeal teeth weak. Mandibles each with four teeth. Eyes and
ocelli small.
Thorax distinctly narrower than the head. Petiole with a
high node, and without anterioventral teeth. Postpetiole with
anterioventral flange. Wider than petiole as seen from above
and weakly trapezoidal.
Sculpture: Head with numerous well marked punctures. These
are weaker but noticeable on the thorax.
Pilosity: All surfaces with numerous hairs of moderate
length.
Color: Head, thorax, petiole, postpetiole, and gaster dark
brown. Mandibles, scapes, funiculi, and legs pale yellow or
pale brown.


in Florida. Independent studies have shown that the venom of one of the
new species contains (5Z,8E)-3-heptyl-5-methyl pyrrolizidine, the first
recorded occurrence of this substance in any animal or plant.
In subterranean studies, 50 traps each in an open field and a long
leaf pine-turkey oak woods were baited each month for a year. Five
Diplorhoptrum species came to the traps, three of which were new. The
dominant species in both habitats was SL (D.) carolinensis, while S. (Dj
pergandei was found only in the woods site, and the remaining species
were present in both habitats. The nest locations and foraging terri
tories were mapped and found to have mosaic patterns. Ant activity
nearly stopped between October and November and did not reach high levels
again until the following May. Soil temperature is probably a major fac
tor in this activity pattern. May soil temperatures were five to seven
degrees higher than those in April.
The only Diplorhoptrum species which constructed nest structures at
the soil surface was S^. (D.) pergandei. These structures were crenelated
tumuli constructed for mating flights. The tumuli apparently allow more
sexuals to remain near the soil surface and also provide a surface for
flight takeoff. Mating flights for this species took place one half hour
before dawn from June through August, mostly when there had been rain
in the previous 24 hours.
The predatory activities of Diplorhoptrum were studied. They
readily killed and consumed newly mated imported fire ant queens,
Solenopsis invicta Burn. Several Piplorhoptrum species were also found
to kill and eat the larvae of the Sugar Cane Rootstalk Borer, Diaprepes
abbreviatus (L.). The indications are that Diplorhoptrum species may be
important subterranean predators and should be further investigated for
their potential as biological control agents.
xi


9
living beside or with 33 different species of ants of four subfamilies
(Cook, 1953; Hayes, 1920; King, 1896, 1901a & b; Mall is, 1941; Mann,
1911a; and Wheeler, 1901). S_. ([).) molesta will also live amicably with
the termite Reticuli termes flavipes (Kollar) in the laboratory (Smythe &
Coppel, 1973). The data on Diplorhoptrum species which are freeliving
or lestobiotic are lacking, spotty, or contradictory. While Kennedy
(1938) found four nests of S_. (JD.) texana, all lestobiotic, Wheeler and
Wheeler (1963) made 81 collections of which 53 were independent nests.
They were unable to determine if the ants were S.. (jl.) molesta or
S.. (£.) molesta val idiuscula. They found that the independent nests
had V1 dia. chambers as much as 5" below the soil surface, but mostly
in the upper 2V. As Wheeler (1901) pointed out, however, there could
be long connecting galleries between these species and their suspected
host galleries or no relationship at all.
Diplorhoptrum are themselves hosts of a number of guests. Wheeler
discovered the first guest, reported only as a Hymenopteran (Brues,
1903). Fall (1920) found a new species of blind beetle Alaudes alternata
Fall in S^. ([).) molesta nests. King (1895, 1897) observed a mite on
larvae which attached midway between the thorax and abdomen and a
Staphylinid of the tribe Aleocharini. Schwarz (1890a & b, 1896) found
Coleptera of the genera Lithocharis and Myrmecochara with S_. (D.)
mol esta, but believed the former to be an accidental guest. Wickham
found the latter beetle with the ants, first calling it Gyrophaena sp.
but later correcting the name (1892, 1894) to Myrmecochara crinita
Casey. He felt this species to be a true myrmecophile along with
Atheta exilissima Casey. Wing (1951) found a number of wasp guests of
the genera Buresopria and Auxopaedeutes, and Loxotropa cal ifornica
Ashmead.


15
Field Studies
Collecting Techniques
Unlike many terrestrial ant species, Diplorhoptrum have few
surface indications of nest location, with the exception of S_. (JD.)
pergandei mating flight tumuli (Figure 29). Diplorhoptrum are
nocturnal and, even at night, forage little above ground except in
moist areas. As a result, conventional methods were not as effective
in locating and collecting these ants; however, the following
techniques were utilized with some success:
1. Lifting bark from bases of trees and from rotten logs.
Species most frequently obtained were S^ (th) pergandei and S^ (I).)
carolinensis.
2. Searching for unnatural soil disturbances such as slight
mounds and color changes indicating excavations, or for parts of dead
insects grouped in one place.
3. Overturning stones, logs, and other soil cover and tearing
apart rotten logs.
4. Searching shovelfuls of soil for foragers, particularly in
moist areas and along the edges of tree roots. Although this method
would seem time consuming and the finding of any ants a matter of
chance, it was one of the most effective. One morning's work and
nearly 200 shovelfuls produced one S^. (jD.) carol inensis queen and
workers and an additional sample of workers; a second morning's work
produced one S^. (JD.) pergandei queen and colony. In a third area one
half hour of work produced two S_. (ID.) carol inensis queens and colones.


60


34
4. Solenopsis (Diplorhoptrum) molesta (Say)
Myrmica molesta Say, 1836. Boston J. Natur. Hist. 1:293.
Myrmica minuta Say, 1836. Boston J. Natur. Hist. 1:293.
Myrmica (Tetmamorium) exigua Buckley, 1867. Proc. Entomol.
Soc. Philadelphia 6:342-3.
Solenopsis debilis Mayr, 1886. Zool.-Bot. Gesell. Wien, Verh.
36:461.
Solenopsis molesta var. validiuscula Emery, 1895. Zool. Jahrb.,
Abt. f. System. 8:278.
Solenopsis (Diplorhoptrum) molesta (Say), Creighton, 1950.
Bull. Mus. Comp. Zool. 104:237.
Type locality: Indiana
Types: No longer in existence
Range: Reported from east and central U.S. from the Gulf States to
Canada. Supposedly rare in the southern areas of the Gulf
States.
Diagnosis:
Head and thorax robust, broad in relation to length. In profile
the petiole considerably larger than the postpetiole, but seen from
above the postpetiole much wider than the petiole. Differs from
carolinensis and texana in having a distinctly broader thorax. Hairs
are sparse and of mixed lengths. No obvious piligerous punctures.
Discussion:
It is this species name which has been most abused in the litera
ture. Authors are legion (Browne and Gregg, 1969; Mann, 1911; Robbins,
1910; Rees and Grundmann, 1940; Talbot, 1975; Yensen and Clark, 1977)
who list this ant, but give little or no additional information. For


37
Sculpture: All surfaces smooth and shining. Piligerous
punctures on dorsum of head weak and not noticeably interrupting
the surface.
Pilosity: Head with rather short, sparse hairs. Thorax
with longer hairs in moderate numbers. Gaster also moderately
beset with hairs.
Color: The head, thorax, petiole, postpetiole, and gaster
dark brown; antennae and legs, including coxae, very pale brown,
almost whitish.
Female: Unknown?
Male: Unknown?
The purported females and males of nickersoni thus far have not
been found with workers. A match was made by a process of
elimination. All other dark colored females and males occurring
in Florida have been found with conspecific workers. The dark
bodies of nickersoni contrasting with the pale colored appen
dages is a characteristic found in both the workers and the
purported females and males, but descriptions await a collection
of sexuals with workers.
Types:
Holotypea worker from Gainesville, Florida, caught in a Naves
trap on June 16, 1979. Paratype material comprises numerous workers
collected in Gainesville, Ocala, and Apopka, Florida on various dates
with Naves traps. All were collected by C. R. Thompson.


Copyright 1980
by
Catherine Rose Thompson


54


80
Summation Values
CD 0-50
O51-200
[HD 201 -700
Figure 40. Five month (June-Oct., 1979) summation of the
distribution by trapping of (]}.) abdita
in an open field at Gainesville, Florida.