Title: Florida Entomologist
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00098813/00071
 Material Information
Title: Florida Entomologist
Physical Description: Serial
Creator: Florida Entomological Society
Publisher: Florida Entomological Society
Place of Publication: Winter Haven, Fla.
Publication Date: 1989
Copyright Date: 1917
Subject: Florida Entomological Society
Entomology -- Periodicals
Insects -- Florida
Insects -- Florida -- Periodicals
Insects -- Periodicals
General Note: Eigenfactor: Florida Entomologist: http://www.bioone.org/doi/full/10.1653/024.092.0401
 Record Information
Bibliographic ID: UF00098813
Volume ID: VID00071
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: Open Access

Full Text

(ISSN 0015-4040)


(An International Journal for the Americas)

Volume 72, No. 4 December, 1989


Announcement 73rd Annual Meeting ....................................... ............ i
Announcement Forum Section ............................................. ................. i

MAHMOOD, F., AND J. K. NAYAR-Effects of Dirofilaria immitis (Nematoda:
Filarioidea) Infection on Life Table Characteristics of Susceptible and Re-
fractory Strains of Aedes aegypti (Vero Beach) (Diptera: Culicidae) ...... 567
MAHMOOD, F., AND J. K. NAYAR-Effects of Dirofilaria immitis (Nematoda:
Filarioidea) Infection on the Rate of Diuresis in Susceptible and Refractory
Strains of Aedes aegypti (Vero Beach) (Diptera Culicidae) .................. 579
ALI, A., M. S. WEAVER, AND E. COTSENMOYER-Effectiveness of Bacillus
thuringiensis serovar. israelensis (Vectobac 12 As) and Bacillus sphaericus
2362 (ABG-6232) Against Culex spp. Mosquitoes in a Dairy Lagoon in
Central Florida .............................................................................. 585
HAACK, R. A., R. F. BILLINGS, AND A. M. RICHTER-Life History Parameters
of Bark Beetles (Coleoptera: Scolytidae) Attacking West Indian Pine in the
Dom inican Republic ....................................................................... 591
PECK, S. B.-A Survey of Insects of the Florida Keys: Post-Pleistocene Land-
Bridge Islands: Introduction ........................................................... 603
PECK, S. B., AND C. BENINGER-A Survey of Insects of the Florida Keys: Cock-
roaches (Blattodea), Mantids (Mantodea), and Walkingsticks, (Phas-
matodea) 612
SCHEFFRAHN, R. H., N.-Y. Su, AND J. R. MANGOLD-Amitermes floridensis,
a New Species and First Record of a Higher Termite in the Eastern United
States (Isoptera: Termitidae: Termitinae) .......................................... 618
KEFFER, S. L., J. T. POLHEMUS, AND J. E. MCPHERSON-Notes on Critical
Character States in Telmatotrephes (Heteroptera: Nepidae) .................. 626
FAIRCHILD, G. B., AND R. S. LANE-A Second Species of Fossil Stenotabanus
(Diptera: Tabanidae) in Amber from the Dominican Republic .............. 630
Hybrid Imported Fire Ants .............................................................. 632
HOWARD, F. W., B. J. CENTER, AND F. W. MEAD-Eye Color Changes Due to
Pigment Migration in Some Species of Heteroptera and Homoptera ....... 637
KIDDER, G. W., III, AND S. K. SAKALUK-A Simple and Inexpensive Electronic
Device for Automatic Recording and Analysis of Insect Acoustical Activity 642
GIESEL, J. T., J. F. ANDERSON, AND C. A. LANCIANI--Comparative Energetics
of Two Species of Drosophila in Florida .......................................... 649
WALKER, T. J., AND T. G. FORREST-Mole Cricket Phonotaxis: Effects of Inten-
sity of Synthetic Calling Song (Orthoptera: Gryllotalpidae: Scapteriscus
acletus) ......................................................................................... 655
PORTER, C. C.-New Chilean Itamuton (Hymenoptera: Ichneumonidae: Mesoste-
nini) Reared from Elicura litigator (Neuroptera: Myrmeleontidae) ......... 660
PORTER, C. C.-Compsocryptus of the Northern Caribbean with Description of a
New Species from Hispaniola (Hymenoptera: Ichneumonidae) .............. 665
HILBURN, D. J., AND R. D. GORDON-Coleoptera of Bermuda ..................... 673
SCHUSTER, J. C.-Petrejoides salvadorae sp. nov. (Coleoptera: Passalidae) from
E l Salvador ................................................................................... 693

Continued on Back Cover

Published by The Florida Entomological Society

President ...................................................................................... J. E E ger
President-E lect .............................................................................. J. F. Price
Vice-President .............................................................................. J. L. Knapp
Secretary ..................................................................................... J. A Coffelt
Treasurer ................................................................................... A C Knapp
Other Members of the Executive Committee
R. S. Patterson J. E. Pena F. D. Bennett M. Lara
M. Camara R. Coler
J. R. McLaughlin, USDA/ARS, Gainesville, FL ..................................... Editor
Associate Editors
Agricultural, Extension, & Regulatory Entomology
Ronald H. Cherry-Everglades Research & Education Center, Belle Glade, FL
Michael G. Waldvogel-North Carolina State University, Raleigh, NC
Stephen B. Bambara-North Carolina State University, Raleigh, NC
Biological Control & Pathology
Ronald M. Weseloh-Connecticut Agricultural Experiment Sta., New Haven, CT
Book Reviews
J. Howard Frank-University of Florida, Gainesville
Chemical Ecology, Physiology, Biochemistry
Louis B. Bjostad-Colorado State University, Fort Collins, CO
Ecology & Behavior
Theodore E. Burk-Dept. of Biology, Creighton University, Omaha, NE
John Sivinski-Insect Behavior & Basic Biology Laboratory, Gainesville
Forum & Symposia
Carl S. Barfield-University of Florida, Gainesville
Genetics & Molecular Biology
Sidhar K. Narang-Insects Affecting Man & Animals Laboratory, Gainesville
Medical & Veterinary Entomology
Arshad Ali-Central Florida Research & Education Center, Sanford, FL
Omelio Sosa, Jr.-USDA Sugar Cane Laboratory, Canal Point, FL
Systematics, Morphology, and Evolution
John B. Heppner-Florida State Collection of Arthropods, Gainesville
Michael D. Hubbard-Florida A&M University, Tallahassee
Howard V. Weems, Jr.-Florida State Collection of Arthropods
Willis W. Wirth-Florida State Collection of Arthropods
Business M manager ....................................................................... A. C. Knapp
FLORIDA ENTOMOLOGIST is issued quarterly-March, June, September, and De-
cember. Subscription price to non-members is $30 per year in advance, $7.50 per copy;
institutional rate is $50 per year. Membership in the Florida Entomological Society,
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Send to: John R. McLaughlin, 4628 NW 40th Street Gainesville, FL 32606.
This issue mailed December 22, 1989


The 73rd annual meeting of the Florida Entomological Society will be held August
5-9, 1990 at the Camino Real Hotel in Cancun, Mexico. Travel and hotel arrangements
are being handled through Holbrook Travel, 3540 N.W. 13th Street, Gainesville, FL
32609 (Phone 1-800-345-7111), Attn: Ms. Joyce Rickard. Registration forms and addi-
tional information will be mailed to members and will appear in the Newsletter and
March issue of Florida Entomologist.


The deadline for submission of papers and posters for the 73rd annual meeting of
the Florida Entomological Society will be May 15, 1990. The meeting format will contain
seven symposia so there will be concurrent sessions. Submitted papers will be eight
minutes allocated for the oral presentation with two minutes for discussion. A separate
Poster Exhibit Session is planned. There will be student paper and poster sessions with
awards as in previous years. Students participating in these judged sessions must be
members of the Society and registered at the meeting.

For additional information contact:
Joseph L. Knapp, Chairman
Program Committee, FES
University of Florida
Citrus Research and Education Center
700 Experiment Station Road
Lake Alfred, FL 33850

A New Type of Article for our Authors and Subscribers

We are proud to announce that, beginning in 1990, scientists may submit articles
for publication in a FORUM section of Florida Entomologist. FORUM articles (1-2 per
issue) will appear at the beginning of each issue in a section marked FORUM. If avail-
able, the first FORUM articles will appear in the June 1990 issue.
Articles for the FORUM section must follow the general style guidelines for all
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Submitted articles should include "Submitted to Florida Entomologist: FORUM"
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for FORUM publications.
We feel the addition of a FORUM section will'expand the scope of Florida En-
tomologist and allow readers and publishing scientists an additional creative outlet that
will complement our symposia, research articles, and notes.

Mahmood & Nayar: Filarial Infection of Aedes aegypti 567


IFAS-University of Florida, Florida Medical Entomology Laboratory
200 9th Street S.E., Vero Beach, Florida 32962


The effects of Dirofilaria immitis (Leidy) infection on the life table characteristics
of selected refractory and susceptible Aedes aegypti L. (Vero Beach) strains were
studied under uninfected and infected conditions. The expectation of life at emergence
(ex) of the infected susceptible females was significantly lower than that of both of the
uninfected strains and of the refractory infected strain. The net reproduction rate (Ro)
was the highest in uninfected refractory females, while it was lowest in the infected
susceptible females. The uninfected refractory strain had the highest values of instan-
taneous birthrate (b) and instantaneous death rate (d); whereas the lowest values of b
and d were in the infected susceptible strain. No interaction was present for the mean
generation time (G), age in days at mean cohort reproduction (To), instantaneous rate
of increase (r,) or their ratios, r,/b, and b/d. The refractory mosquitoes lived longer
than the susceptible mosquitoes under both uninfected and infected conditions, con-
sequently, the age at maximum reproduction was significantly earlier in the refractory
mosquitoes and resulted in their higher rm values. The uninfected refractory females
laid more eggs than the infected refractory, uninfected susceptible, and infected suscep-
tible females throughout their life span. The D. immitis infection caused significant
mortality in the susceptible strain due to the migration of microfilariae to the Malpighian
tubules, at the time of the molt from first stage (L1) to second stage (L2), and when
infective stage larvae (L,) left the Malpighian tubules. The major causes of mortality
in refractory strain were the migration of the microfilariae to the Malpighian tubules
and due to the damage caused by the constant movement of the moribund prelarvae
inside the Malpighian tubules.


Se estudiaron los efectos de infecci6n de Dirofilaria immitis (Leidy) sobre las carac-
teristicas de la tabla de vida de razas seleccionadas refractarias y susceptibles de Aedes
aegypti L. (Vero Beach) bajo condiciones infectadas y no infectadas. La expectaci6n de
vida al merger (ex) de hembras susceptibles infectadas fue significativamente mas baja
que la raza no infectada y la raza refractaria infectada. La raza refractaria no infectada
tuvo el valor mas alto de tasa de nacimiento instantAneo (b) y de muerte instantanea
(d); mientras que los valores mAs bajos de b y d ocurrieron en la raza susceptible
infectada. No ocurri6 una interacci6n entire tiempos de generaci6n (G), entire la edad en
dias del promedio de reproduccion del cohorte (T), en la tasa de aumento instantaneo
(rm) o en su proporci6n, rm/b, y bid. Los mosquitos refractarios vivieron mas tiempo
que los mosquitos susceptibles bajo ambas condiciones de infecci6n y de no infecci6n,
consecuentemente, la edad de maxima reproducci6n fue significativamente mas temprano
en los mosquitos refractados y result en valores mas altos de rm. Las hembras refrac-
tadas no infestadas pusieron mas huevos que las refractadas infestadas, que las suscep-
tibles no infectadas, y que las hembras susceptibles infectadas durante toda su vida.
Infecci6n de D. immitis caus6 una mortalidad significant en la raza susceptible debido
a la migraci6n de microfiliaras a los tubos de Malpigios durante el period de muda de
la primera etapa (L1) a la segunda etapa (L2), y cuando la etapa larval (L3) sali6 del

568 Florida Entomologist 72(4) December, 1989

tubo de Malpigio. La mayor causa de la mortalidad de la raza refractoria fu6 la migraci6n
de microfilaria a los tubos de Malpigio y debido al daho causado por el movimiento
constant de pre-larvas moribundas dentro de los tubos de Malpigio.

Dirofilaria immitis (Leidy) (Nematoda: Filarioidea) spends part of its life cycle in
a mosquito vector. The microfilariae of D. immitis migrate after ingestion from the
midgut of the mosquito to the primary cells of the Malpighian tubules, where they
become intracellular and develop in susceptible mosquitoes through two molts to the
infective larval stage (L3) (Kartman 1953, Taylor 1960). Development of D. immitis and
other filariids in the mosquito vectors can cause pathological effects, which can sub-
sequently reduce the vector's survival and fecundity (Kershaw et al. 1953, Kershaw &
Duke 1954, Javadian & Macdonald 1974, Courtney et al. 1985).
In Aedes aegypti L., infection with D. immitis and Brugia pahangi (Buckley and
Edeson) initially increases mortality when microfilariae reach the target organ (Malpig-
hian tubules and thoracic muscles, respectively), where development occurs, and later
when the infective larvae exit the target organ (Kartman 1953, Kershaw et al. 1953,
Townson 1971). The effect of the filarial infection on the fecundity of vector mosquitoes
is, however, not clearly apparent. The number of eggs developed by Brugia susceptible
Ae. aegypti after the first infective blood meal on B. pahangi or D. repens infected
animals was not significantly different from that of mosquitoes having a first uninfected
blood meal (Javadian & Macdonald 1974). But when both groups of infected mosquitoes
were provided with an uninfected second blood meal, the infected mosquitoes laid signif-
icantly smaller egg batches. This difference was attributed to the larger size and greater
nutritional requirement of older developing filarial larvae during the second gonotrophic
cycle of the mosquitoes (Javadian & Macdonald 1974). Similarly, in Ae. trivit-
tatus(Coquillett), egg production decreased as parasite burden increased, but only mos-
quitoes harboring more than 15 larvae of D. immitis showed significant reduction in
egg production (Christensen 1981).
We have isolated highly susceptible and highly refractory strains of Ae. aegypti
(Vero Beach) to D. immitis infection by the individual sibling mating method of
McGreevy et al. (1974). Dirofilaria immitis larvae develop normally from microfilariae
to infective third stage larvae in the highly susceptible strain of Ae. aegypti, similar to
that described by Taylor (1960). On the other hand, in the highly refractory strain of
Ae. aegypti, the microfilariae do not develop (Sauerman & Nayar 1985). The present
study was conducted to determine the effect of D. immitis infection on the life table
characteristics, especially survival and reproductive potentials, of the highly susceptible
and the highly refractory strains of Ae. aegypti (Vero Beach).



Highly susceptible and highly refractory strains of Ae. aegypti (Vero Beach) were
used throughout the study. All experiments were conducted at 25C, 80% relative
humidity and 12:12 LL:DD photoperiod.


Eggs collected from gravid females of both the susceptible and the refractory strains
were hatched in an egg hatching medium, prepared by adding a small amount of Brew-

Mahmood & Nayar: Filarial Infection of Aedes aegypti 569

ers yeast to boiled water. Groups of 100 first instar larvae of each strain were counted
into 12 enamel pans (34 x 21.5 cm) with glass lids containing 500 ml of water. The larvae
were provided daily a measured amount of a 1:1 mixture of Brewers yeast and liver
powder. A total of 1000 mg of food was added to each pan during the entire rearing
period. Pupae were picked daily from each pan and were placed in separate emergence
cups. Newly emerged adults were lightly anesthesized with chloroform and were sexed
and recorded by pan number and date of emergence.


Twelve groups of 25 newly emerged males and 25 females were allowed to cohabit
in 3.8 liter ice cream carton cages. A 10% sugar solution was provided for ad lib. feeding
and was changed every three days. Six of these groups were used as uninfected controls
and were fed daily for 30-45 minutes on tethered chicken from one day after emergence
until the day the last mosquito died. The mosquitoes from the remaining six groups of
each strain were fed daily for 30-45 minutes on the hind legs of a dog, naturally infected
with D. immitis, for 4 days starting from one day after emergence. At the time of these
experiments the microfilaremia was between 40-60 microfilariae per microliter of
cutaneous blood. During these 4 days all the females fed to repletion, thereafter, these
infected females were allowed to feed daily for 30-45 minutes on tethered chicken until
the day the last mosquito died.
Dead mosquitoes were removed and recorded daily and the remaining mosquitoes
were provided a blood meal on a restrained chicken. A petri dish (15 x 4 cm), lined with
wet filter paper, was provided daily for oviposition. The oviposition petri dishes contain-
ing the eggs were kept separate by the date of oviposition and the cage number. The
eggs were allowed to incubate for 15 days and were then hatched in the egg hatching
medium for two days. The medium was filtered and the eggs dried again at 25C for an
additional two days and then again immersed in the hatching medium for 2 days. The
eggs were classified into three categories: hatched, unhatched embryonated and unem-
bryonated eggs.
Additionally, a group of 300 mosquitoes of each strain was fed on the infected dog
and ten mosquitoes were dissected daily from each strain to follow their developmental


The statistical methods, formulae, rationale and terminology described previously
(Reisen et al. 1979, Reisen & Mahmood 1980) were used to calculate life table paramet-
ers including life expectancy at emergence (ex in days), net reproductive rate (Ro in
females per female per generation), the mean age of reproduction (To in days), the
intrinsic rate of increase (rm in females per female), the instantaneous birth rate (b in
females per female) and generation time (G in days). In addition, various immature
developmental characteristics of both the strain were compared using Student's t-test,
which was adjusted to take into account any significant differences in the variances.
The percent survivorship data were transformed to arcsine before subjecting to Stu-
dent's t-test. The different life table attributes were also compared by using two-way
analysis of variance.


The immature survivorship from first instar larvae to pupae and from first instar
larvae to adults were significantly greater for the refractory strain as compared to the

Florida Entomologist 72(4)

susceptible strain, but there was no significant difference in survivorship from pupae
to adults for either strain (Table 1). Similarly, the survivorship of males and females
from first instar to adult, the median pupation and median emergence times of females
were not significantly different when tested by X2 and Student's t-test, respectively
(Table 1). The median emergence time of refractory males was significantly earlier than
the males of the susceptible strain (Table 1). There was no significant difference between
the sex ratio of the two strains.
Normal development of D. immitis larvae observed in the Malpighian tubules of the
susceptible females was similar to that described by Taylor (1960). Microfilariae, which
were very mobile and 300 15L in length, entered the Malpighian tubules within 24
h of the infective blood meal, became intracellular and changed to immobile L1 stage,
which first decreased in length to 150 10R and then increased in length to 217 + 4[
during the next 4 days. On the 9th day, these larvae increased to 460 5 in length
and molted to the second stage (L2) larvae. These larvae further increased in length to
1100 - 10 by the end of the 13th day. During the next 2 days, these larvae molted to
the third stage (L3) larvae, and were 1300 181 in length. The larvae were now very
active and moved out of the Malpighian tubules into the hemocoel and then to the head
capsule, where they stayed until they were transmitted during the next blood meal.
There was substantial cellular damage to the Malpighian tubule cells during the devel-
opment of the larvae.
In refractory females, the microfilariae migrated from the midgut to the Malpighian
tubules, where their development was arrested. These microfilariae, called prelarvae,
became moribund and caused some cellular damage at the distal and proximal ends of
the Malpighian tubules due to their constant spasmodic movement.
The expectation of life at emergence (ex) of females was not significantly different
in the uninfected refractory (40.5 days) and susceptible strains (33.5 days); but it was
significantly longer than the infected females (11.0 and 8.9 days, respectively) (Table
2). A large number of females of both the strains died during the first four days after
ingestion of an infective blood meal as depicted by the lx curves (age specific survivor-
ship curves) (Fig. la and Ib). This initial sharp decline in survival of the infected females


Attributes Susceptible Refractory

Total Survivorship:
First instar larva-Adult 0.81 0.08 0.91 0.041
First instar larva-Pupa 0.85 0.07 0.93 0.051
Pupa-Adult 0.96 + 0.03 0.095 0.03
First instar larva-Adult (3) 0.71 0.893
First instar larva-Adultg (9) 0.91 0.943
Median pupation time (days): 7.11 0.32 6.64 1.012
Median emergence time (days):
Female 9.49 0.79 9.04 0.482
Male 9.39 9.50 8.42 1.012
Sex ratio:
Males/Total adults 0.56 0.05 0.52 0.08

'Means indicated in each row were significantly greater when compared by Student's t-test P < 0.05.
'Means in each row were not significantly different when compared by Student's t-test.
'Means in each row were not significantly different when compared by x2 test.

December, 1989

Mahmood & Nayar: Filarial Infection of Aedes aegypti 571

was due to trauma and injury caused during the migration of the microfilariae from the
midgut into the Malpighian tubules in both strains. At 6 days after emergence, i.e., 2-3
days after an infective blood meal, 67% of 150 infected refractory females were alive as
compared to 59% of the 150 infected susceptible females (Figs. lb and Id). But the rate
of mortality continued to increase for the infected refractory females and they died
faster as compared to the infected susceptible females, with the result that at 6-8 days
after an infective blood meal 50% of the infected females were dead in both strains (Fig.
la and Ib). The increase in the number of dead females during the time period for the
refractory strain might be due to the cellular damage caused by the continued spasmodic
movement of the moribund prelarvae, whereas, in the Malpighian tubules of the suscep-
tible females the first stage larvae were inactive. The next decline for ex among infected
susceptible females was observed at the time of molting of first (L1) to second (L2) stage
larvae of D. immitis, i.e., at 12-14 days after emergence of females. An increased
mortality was also observed at the time of exit of third stage infective (L3) larvae from
the Malpighian tubules, i.e., 16 days after emergence of females, at this time infective
larvae were present in the hemocoel, thorax and head of the susceptible females. After
16 days the lx curves were similar in both the infected refractory and susceptible strains
(Fig. la and Ib). No interaction was present in ex of females between the two strains
and their state of infection.
The ex at emergence of males showed a significant interaction (P < 0.05) (F = 6.2),
since the susceptible males in groups with the infected females had significantly longer
ex at emergence than the males in groups with uninfected females (Table 2).
The net reproductive rate (Ro) in females progeny per female per generation had a
significant interaction (P < 0.05) (F = 35.5). The uninfected refractory females showed
the highest Ro (314.0 + 64.1, R sd) and this is very well depicted by their lxmx curve
(Fig. Ic). The maximum reproductive effort (lxmx) value, i.e., 27.4, was observed for
the uninfected refractory females as compared to the infected refractory (8.8), unin-
fected susceptible (12.1) and infected susceptible females (4.9) (Figs. la-ld). The lowest
value of Ro was observed for the infected susceptible females (Table 2). Both uninfected
refractory and susceptible females had higher Ro values than their infected counterparts
(Table 2).
The females of the refractory strain lived longer than the females of the susceptible
strains in both the uninfected and infected groups, consequently, the mean generation
time (G) and the mean age of reproduction (To) were later for them than of the suscep-
tible females (Table 2). No significant interaction was present in the value of G of both
strains whether infected or not (P < 0.05), but the uninfected refractory females had
significantly longer G than the infected refractory females. Similarly uninfected suscep-
tible females had longer G than the susceptible infected females (P < 0.05) (F = 28.6
and F = 10.7, respectively) (Table 2). The mean age of reproduction (T,) was signifi-
cantly greater for the refractory females than the susceptible females (P < 0.05) (F =
8.9) (Table 2). Similarly, infected refractory females and infected susceptible females
had significantly smaller values of To than the uninfected females (P < 0.05) (F = 33.5)
(Table 2). There was no interaction between either strain and its state of infection (P
< 0.05).
Although the age at first reproduction was not different in the two strains, the age
at maximum reproduction, was significantly earlier (P < 0.05) for the refractory females
(Fig. la to Id) and resulted in their higher values of instantaneous rate of increase (rm)
(Table 2). The rm value was significantly greater for the refractory females than the
susceptible females (P < 0.05) (F = 4.6). The uninfected refractory females and unin-
fected susceptible females had greater rm values than their respective infected counter-
parts (P < 0.05) (F = 52.4) (Table 2).

Florida Entomologist 72(4)


December, 1989









0 10 20 30 40 50 60 70 80 90


Mahmood & Nayar: Filarial Infection of Aedes aegypti 573

A significant interaction was present for the instantaneous birth rate (b) between
the two strains and their state of infection (P < 0.05) (F = 15.9) (Table 2). The highest
value of b was for uninfected refractory females and lowest value of b was for infected
susceptible females (Table 2). Similarly, a significant interaction existed between the
type of strains and their state of infection for the instantaneous death rate (d) (P <
0.05) (F = 6.9) (Table 2). The highest value of d was for the uninfected refractory
females and lowest value of d was observed in infected susceptible females (Table 2).
The rm/b and b/d ratios were not significantly different and their was no interaction
present between either strain and its state of infection (P < 0.05) (Table 2).
A higher percentage of the infected refractory (85.7%) and infected susceptible
(92.9%) females were present in the younger classes of the stable age distribution or
the proportion of the population falling into each age class (1-6 days) as compared to
the uninfected refractory (82.2%) and uninfected susceptible (71.5%) females (Figs.
2a-2d). The presence of a higher proportion of the infected females in the lower age
distribution classes suggested that a larger proportion of the infected females died
earlier in life.
Total number of eggs laid by and the mean percentage of hatched eggs from one
female each week during their life span for all the four different groups is presented in
Table 3. No differences were observed for the number of eggs laid by uninfected and
infected susceptible females during the first four weeks of their life (P < 0.05). The
percent hatch was significantly lower for the infected "susceptible females (P < 0.05).
The proportion of females laying higher number of unembryonated eggs increased in
older females for the uninfected refractory females. There was no significant difference
for the number of eggs laid per female per week during the first 7 weeks by refractory
females, whether uninfected or infected (P < 0.05) (Table 3). There was a significant
difference in the total number of eggs laid per female during their life span among all
the four groups (P < 0.05, F = 1.6).


The present study suggested that the genotype of the mosquitoes does not affect
their survival during immature development and that the eggs laid by susceptible
females had an equal chance of reaching adulthood as those laid by refractory females.
The immature survivorship of both susceptible and refractory strains was similar to
that observed in field collected Ae. aegypti (Gainesville) by Wijeyaratne et al. (1974).
The larval development time was similar to their laboratory observed value of 8-9 days
but was less than their field values which could be due to differences in temperature
and/or food. The male larvae developed faster than the female larvae which agreed with
the observations of Putnam & Shannon (1934). The rate of female larval development
was faster in the present study.
Life table characteristics of Ae. aegypti, which were fed fruit juices and blood were
determined by Putnam & Shannon (1934). The life expectancy of their mosquitoes was
greater than that observed here for the uninfected refractory females in the present

Fig. 1. The age specific survivorship in individuals per individual per day (Lx) and
reproductive effort in the number of female off-springs produced per living female per
day (lxmx), plotted as a function of age in days of a) infected refractory females, b)
infected susceptible females, c) uninfected refractory females, and d) uninfected sus-
ceptible females of Aedes aegypti. 1l females -*-*-*-*-, ix males -o-o-o-o-, and lxmx
females A--------A. The area under lxmx curve represents the mean net reproductive
rate per cohort (Ro). Each point represents the mean of 6 replicated groups.


Susceptible Refractory
Uninfected Infected Uninfected Infected
Attributes (R + sd) ( t sd) (R + sd) ( + sd)

Mean life expectancy 33.5 2.3be 8.9 1.2d 40.5 11.0ace 11.0 2.4
(days) (ex Y)
Mean life expectancy 19.9 1.7 21.7 3.3de 21.5 2.7a 16.7 3.8e
(days) (ex d)
Reproduction rate (Ro) 98.2 20.0b 24.4 11.5 314.0 64.1ac 64.2 24.2
Mean age of reproduction (To) 18.1 2.4b 9.6 2.6 21.2 3.9ac 14.4 3.8d
Instantaneous rate of 0.28 0.02 0.23 0.03 0.3 0.01ac 0.24 0.2
increase/9 (rm)
Mean generation time (G) 16.1 1.8b 13.4 1.6 18.2 + 0.5ac 17.3 1.1d
Instantaneous birth rate (b) 1.1 0.2b 0.9 0.1 1.9 0.10 1.3 0.2d
Instantaneous death rate (d) 0.8 0.1b 0.7 0.1 1.6 0.1ac 1.1 0.2d
Ratio rm/b 0.23 0.02 0.25 0.01 0.2 0.01O 0.2 0.01
Ratio b/d 1.4 0.04 1.33 0.02d 1.2 0.01e 0.2 0.1

'Means significantly greater (P < 0.05) when compared by unpaired Student's t-test; a = comparison uninfected refractory strain and infected refractory strain; b comparison between
uninfected susceptible strain and infected susceptible strain; c uninfected refractory strain compared to uninfected susceptible strain; d = infected refractory strain compared to infected
susceptible strain; e, mean life expectancy from emergence in days of females compared to the mean life expectancy in days from emergence of males. Each value represents the mean of 6
replicated groups.

Mahmood & Nayar: Filarial Infection of Aedes aegypti 575

25r a


0 5 10 15 20 25 0

5 10 15 20 25

0 5 10 15 19 0 5 10 15 20 23


Fig. 2. The stable age distribution of the refractory and susceptible Aedes aegypti
(Vero Beach) strains to Dirofilaria immitis infection, plotted as a function of age. a)
uninfected refractory females, b) infected refractory females, c) uninfected susceptible
females, d) infected susceptible females. Each figure represents the mean of 6 replicated

study. In multivoltine species, the best comparison between the capabilities of two
species which occupy the same habitat is their rm value (Hacker 1972). In the present
study the uninfected refractory strain of Ae. aegypti had a significantly higher value of
rm (0.32) than the susceptible strain (0.28). The value of rm can also be affected by the
age of maximum reproduction (MacArthur & Wilson 1967). The time of maximum repro-
duction was one day earlier in the refractory strain than in the susceptible strain.
A comparison of the infected refractory and infected susceptible females showed
that the initial mortality was similar for both the strains, but from the 4th day to the
7th day it was significantly greater for the susceptible strain which agreed with the



Susceptible' Refractoryl
Uninfected Infected Uninfected Infected
Time No. eggs % eggs No. eggs % eggs No. eggs % eggs No. eggs % eggs
(week) per /week hatched per /week hatched per /week hatched per /week hatched

1 66.8 58.4 21.9 37.2 51.9 26.6 114.9 92.7 3.0 61.6 85.9 4.5
2 129.3 80.8 3.4 158.8 70.5 12.0 197.6 91.7 2.0 200.9 92.2 3.3
3 157.5 76.5 4.4 176.6 68.6 9.0 218.2 93.7 1.2 211.9 88.7 6.3
4 129.3 74.1 8.2 129.4 36.4 23.7 186.6 89.9 8.0 158.8 93.4 4.2
5 157.5 59.2 7.2 60.1 50.2 3.0 159.8 84.5 3.4 128.4 81.5 32.6
6 126.6 46.8 20.8 30.0 0.0 166.1 83.2 7.3 169.5 91.7 6.7
7 108.1 25.0 16.9 102.1 72.1 11.8 119.3 80.9 10.9
8 118.5 41.7 41.7 109.8 59.2 18.1 129.0 75.2 3.9
9 157.4 30.8 41.6 119.8 48.3 18.7 67.5 89.7 2.6
10 94.4 1.92 77.0 26.6 14.9 40.0 95.02
11 56.6 13.9 22.1
12 113.6 1.7 2.2
13 79.3 7.5 15.1
14 29.5 0.7 1.0
eggs 84,378 15,567 143,874 27,771
Total percent
hatch 69.96 58.78 84.89 90.37

'Each value represents the mean of 6 replicated groups.
2Eggs were laid on one day only during the week.

Mahmood & Nayar: Filarial Infection of Aedes aegypti 577

earlier observations by Townson (1971), who observed higher mortalities for the suscep-
tible females of Ae. aegypti infected with Brugia pahangi. The rm values can as well
depend upon the number of microfilariae initially ingested by the females while feeding
on an infected dog; because females with more prelarvae died earlier. In the present
study more microfilariae moved into the Malpighian tubules of the susceptible females
than in the refractory females as was observed by Sulaiman & Townson (1980). Initial
mortalities were observed within 48 h after an infective blood meal in both strains which
agreed with the observation of Ramachandran (1966), who noted a direct relationship
between the load of microfilariae of Brugia malayi and the initial mortality in the Ae.
aegypti. Increased mortality resulted when third stage larvae exited the Malpighian
tubules and were present in the hemocoel, thorax and head of the females; and might
be related to the utilization of tissues or the nutrients present in the body of the females
(Kershaw et al. 1953). No such stress was imposed on the infected refractory females
by the moribund prelarvae (Sauerman & Nayar 1985).
Differences were found in the egg hatch percentage of susceptible and refractory
females in this study with uninfected susceptible females showing a significantly lower
percentage of hatched eggs than the uninfected refractory females. The reduction in
the percent egg hatch rate of older uninfected refractory females might be due to the
monogamous nature of Ae. aegypti females (Craig 1967). The percent egg hatch of
infected susceptible females was less than the uninfected susceptible females and was
possibly due to the D. immitis infection resulting in leSs active females.
In conclusion the present study suggested that the ingestion of the microfilariae
decreased the life expectancy and reproductive potentials of Ae. aegypti and this effect
was more pronounced later in the life of infected susceptible females than in the infected
refractory females.


This study was supported by grant No. AI 17736 from the NIH-NIAID. We wish
to thank W. K. Reisen of the Arbovirus Field Station, Bakersfield, California for critical
reading of the manuscript. This is part of a thesis submitted to the Graduate School of
the University of Florida, IFAS, University of Florida, Gainesville, Florida by Farida
Mahmood. University of Florida Experiment Station Journal Series No. 7962.


CHRISTENSEN, 8. M. 1981. Observations on the immune response of Aedes trivittatus
against Dirofilaria immitis. Trans. R. Soc. Trop. Med. Hyg. 75: 438-443.
Dirofilaria immitis on blood meal size and fecundity in Aedes aegypti (Diptera:
Culicidae). J. Med. Entomol. 22: 398-400.
CRAIG, G. B. 1967. Mosquitoes: Female monogamy induced by male accessory gland
substance. Science 156: 1499-1501.
HACKER, C. S. 1972. Measuring reproductive potential in populations. Mosquito News
32: 193-196.
JAVADIAN, E., AND W. W. MACDONALD. 1974. The effect of infection with Brugia
pahangi and Dirofilaria repens on the egg production of Aedes aegypti. Ann.
Trop. Med. Parasitol. 68: 477-481.
KARTMAN, L. 1953. Factors influencing infection of the mosquito with Dirofilaria
immitis (Leidy 1856). Exp. Parasitol. 2: 27-78.
KERSHAW, W. E., AND B. O. L. DUKE. 1954. Studies on the intake of microfilariae
by their insect vectors, their survival and their effects on the survival of their
vectors. V. The survival of Loa loa in Chrysops silacea under laboratory condi-
tions. Ann. Trop. Med. Parasitol. 47: 340-344.

Florida Entomologist 72(4)

December, 1989

on the intake of microfilariae by their insect vectors, their survival, and their
effect on the survival of the vectors. I. Dirofilaria immitis and Aedes aegypti.
Ann. Trop. Med. Parasitol. 47: 207-224.
MACARTHUR, R. H., AND E. O. WILSON. 1967. The theory of island biogeography.
Monogr. Popul. Biol. No. 1, Princeton Univ. Press, N.J.
Inheritance of susceptibility to Dirofilaria immitis infection in Aedes aegypti.
Ann. Trop. Med. Parasitol. 68: 97-109.
PUTNAM, P., AND R. C. SHANNON. 1934. The biology of Stegomyia under laboratory
conditions. II. Egg laying capacity and longevity of adults. Proc. Entomol. Soc.
Washington 36: 217-242.
RAMACHANDRAN, C. P. 1966. Biological aspects in the transmission ofBrugia malayi
by Aedes aegypti in the laboratory. J. Med. Entomol. 3: 239-252.
REISEN, W. K., AND F. MAHMOOD. 1980. Horizontal lifetable characteristics of the
malaria vectors Anopheles culicifaces and Anopheles stephensi (Diptera:
Culicidae). J. Med. Entomol. 17: 211-217.
REISEN, W. K., T. F. SIDDIQUI, Y. ASLAM, AND G. M. MALIK. 1979. Geographic
variation among the life table characteristics of Culex tritaeniorhynchus Giles
from Asia. Ann. Entomol. Soc. Am. 72: 700-779.
SAUERMAN, D. M., JR., AND J. K. NAYAR. 1985. Characterization of refractoriness
in Aedes aegypti (Diptera: Culicidae) to infection by Dirofilaria immitis. J.
Med. Entomol. 22: 94-101.
SULAIMAN, I., AND H. TOWNSON. 1980. The genetic basis of susceptibility of infec-
tion with Dirofilaria immitis in Aedes aegypti. Ann. Trop. Med. Parasitol. 74:
TAYLOR, A. E. R. 1960. The development of Dirofilaria immitis in the mosquito
Aedes aegypti. J. Helminthol. 34: 27-38.
TOWNSON, H. 1971. Mortality of various genotypes of the mosquito Aedes aegypti
following the uptake of microfilariae Brugia pahangi. Ann. Trop. Med. Parasitol.
65: 93-106.
ment and survival of a natural population of Aedes aegypti. Mosquito News 34:


Mahmood & Nayar: Filarial Infection of Aedes aegypti 579


Institute of Food and Agricultural Sciences, University of Florida
Florida Medical Entomology Laboratory, 200 9th Street S.E.
Vero Beach, Florida 32962


The effect of Dirofilaria immitis (Leidy) infection on the rate of diuresis was inves-
tigated for infected and uninfected blood-fed females of highly susceptible and refractory
strains of Aedes aegypti L. (Vero Beach). The pattern and course of diuresis were
similar for both infected and uninfected females of both strains. Infection of Malpighian
tubules reduced the rate of diuresis during the peak phase for infected females as
compared to that for the corresponding uninfected females. There were no differences
between strains as to the rate of diuresis in infected females. Infected susceptible
females showed a strong negative linear correlation between the number of developing
D. immitis and the total amount of fluid excreted during the 90-min observation period,
whereas in infected refractory females there was no correlation between the presence
of moribund prelarvae and the total amount of fluid excretion. These results suggested
that the lower rate of diuresis in both infected susceptible and refractory females was
related to damage caused by the developing first stage larvae and moribund prelarvae,


Se investig6 el efecto de infecci6n de Dirofilaria immitis (Leidy) en la tasa de
diuresis de hembras infectadas y no infectadas'de razas refractarias de Aedes aegypti
L. (Vero Beach). que se alimentaron con sangre. El patron y direcci6n de diuresis fue
similar en hembras infectadas y no infectadas de las dos razas. La infecci6n de los tubos
de Malpigio redujo la tasa de diuresis durante la fase del auge de las hembras infectadas
cuando se compare con las correspondientes hembras no infectadas. No hubo diferencih
entire las razas con respect a la tasa de diuresis en las hembras infectadas. Hembras
susceptibles infectadas demostraron una fuerte correlaci6n linear negative entire el nim-
ero de D. immitis en desarrollo y la cantidad total de fluido excretado durante los 90
minutes del period de observaci6n, mientras que en hembras infectadas refractarias
no hubo correlaci6n entire la presencia de pre-larvas moribundas y la cantidad total de
fluido excretado. Estos resultados sugieren que la baja tasa de diuresis en hembras
susceptibles infectadas y en hembras refractarias, estA relacionada al dafio causado por
el desarrollo de la primera etapa de larvas y de larvas pre-moribundas respectivamente.

Soon after female mosquitoes ingest a blood meal, there is rapid excretion of clear
urine involving the Malpighian tubules, called diuresis. In species of mosquitoes studied
thus far, the process of diuresis follows three phases: the peak phase of very rapid urine
elimination during the first 10 minutes, the post-peak phase with a declining rate of
elimination during the next 40 min. and the late phase of fairly constant elimination
during the last 40 minutes of the 90-minute period (Boorman 1960, Nijhout & Carrow
1978, Williams et al. 1983, Nayar & Bradley 1987). Ingested microfilariae of Dirofilaria

580 Florida Entomologist 72(4) December, 1989

immitis (Leidy) develop intracellularly through two molts to the infective stage in the
Malpighian tubules of susceptible mosquitoes (Kartman 1953, Taylor 1960, Nayar &
Sauerman 1975). Nayar & Bradley (1987) showed that, in Aedes taeniorhynchus (Wied-
mann) infected with D. immitis, the rate of diuresis was significantly reduced during
the peak phase of diuresis compared with that of uninfected females. Even greater
reduction in secretion rates during peak and post-peak phases of diuresis were observed
in infected Anopheles quadrimaculatus Say.
We have isolated highly susceptible and highly refractory strains of Aedes aegypti
L. (Vero Beach) to D. immitis infection by the individual sibling mating method of
McGreevy et al. (1974). In the highly susceptible strain, D. immitis larvae develop
normally. The first stage of larval development occurs intracellularly in the primary
cells of the Malpighian tubules and the subsequent two stages develop in the lumen
(Taylor 1960). On the contrary, in the highly refractory strain the microfilariae become
arrested after entering the primary cells of the Malpighian tubules and remain as
moribund prelarvae (Nayar & Sauerman 1975). About 50% of the infected females of
both strains die during the first 6 days after an infective blood meal (Mahmood & Nayar
1989). Among the remaining females of the susceptible strain, most of the Malpighian
tubule cells are damaged due to the development of the first stage larvae, whereas in
the refractory strain the proximal and distal cells of the Malpighian tubules are damaged
due to the constant movement of moribund prelarvae (Nayar & Sauerman 1975). The
present study was designed to investigate the effect ofthis damage on the process of
diuresis in D. immitis infected susceptible and refractory females and to compare this
process with uninfected females.


Highly susceptible and refractory strains of Ae. aegypti (Vero Beach) used in this
study were reared and maintained as described elsewhere (Mahmood & Nayar 1989).
All experiments were conducted at 26 1 C under a 12:12 (L:D) photoperiod and at
RH 75%.
Experimental protocol, measurements of diuresis in uninfected controls and D. im-
mitis infected females of both susceptible and refractory strains, and the rate of infec-
tion in infected females were as described by Nayar & Bradley (1987). Diuresis was
quantified after the method of Nijhout & Carrow (1978) and modified after the method
of Stobbart (1977) by monitoring the loss of weight of blood-fed mosquitoes. Female,
mosquitoes maintained on a 10% sucrose solution, were given their first blood meal to
repletion on an infected dog (peripheral blood count 25 5 microfilariae/l) or (control)
on a chicken 4-5 days after emergence. Blood-fed females from both groups were then
maintained on a 10% sucrose solution and allowed to lay all their eggs. At 5-7 days after
the first blood meal, females from both groups were individually given a second blood
meal to repletion on a chicken. Diuresis in these mosquitoes (20 females per group) was
measured starting immediately after the second blood meal. After measurement of
diuresis, the Malpighian tubules of infected females were directed and the number of
developing larvae was assessed. Rates of weight loss at different times after the infec-
tive blood meal were compared using Student's t-test and the total amount of weight
loss (diuresis) during the 90 min in relation to parasite burden were compared using
linear regression analysis.


The uninfected susceptible females of Ae. aegypti took significantly larger second
blood meals and showed greater weight loss during 90 min. duration of diuresis as

Mahmood & Nayar: Filarial Infection of Aedes aegypti 581

compared to infected susceptible females (Table 1). There was not a significant weight
loss after the second blood meal in refractory uninfected and infected females, the
weight loss for the uninfected was greater (3.93 + 1.12) than for the infected (3.58 -
1.26) females (Table 1). The pattern and time-course of diuresis were similar in both
groups of both strains (Fig. 1). In all four groups, there were significant differences (P
< 0.05, n = 40) in weight loss during the peak phase (0-15 min), and post-peak phase
(16-45 min) after feeding (Fig. 1), with the more rapid weight loss occurring within the
peak phase (Fig. 1). Infected susceptible and refractory females showed slower rates
of diuresis than uninfected susceptible and refractory females (Fig. 1). The rate of
diuresis was faster in uninfected susceptible females than in uninfected refractory
females, but there were no differences in the rate of diuresis in infected susceptible
and refractory females (Fig. 1).
During the initial infection of susceptible and refractory females with D. immitis
(susceptible females ingested 261.4 58.4, x sd and refractory females ingested
376.0 87.7) there was no significant difference (P > 0.05) in the number of micro-
filariae ingested; however, there were significant differences (P < 0.05) in the number
of developing first stage larvae, 5-6 days after initial infection, in the susceptible females
(30.0 27.5) and the number of moribund prelarvae (11.5 9.47) in the refractory
females. The rate of weight loss was smaller in susceptible females with a greater
number of developing first stage larvae of D. immitis and showed a correlation coeffi-
cient (r) of -0.38 (Fig. 2a), whereas in refractory females there was no correlation
between the number of moribund prelarvae and the rate of weight loss (Fig.2b), the
correlation coefficient (r) was -0.15.


These studies showed that D. immitis infected refractory and susceptible Ae.
aegypti females had identical patterns of diuresis and their rates of diuresis were signif-
icantly reduced as compared to those for uninfected females of both strains. These lower
rates of diuresis in infected Ae. aegypti females were similar to those observed in D.
immitis infected Ae. taeniorhynchus and An. quadrimaculatus (Nayar & Bradley


Uninfected Infected

Mosquito wet body weight (mg) 2.80 + 0.312 2.73 0.27
Weight of blood meal (mg) 4.56 1.341 3.33 0.87
Weight loss during diuresis (mg) 2.42 0.741.2 1.56 0.62
Weight loss percent of blood meal 54.20 14.861 44.06 14.87
Mosquito wet body weight (mg) 2.31 0.48 2.41 0.50
Weight of blood meal (mg) 3.93 1.12 3.58 1.26
Weight loss during diuresis (mg) 1.94 0.42 1.46 0.57
Weight los percent of blood meal 52.57 15.65' 41.75 2.07

'Comparison of uninfected and infected mosquitoes after second blood meal. Mean significantly greater when
tested by Student's t-test (P < 0.05).
'Comparison of susceptible and refractory mosquitoes.










Florida Entomologist 72(4)








0 10 20 30 40 50 60 70 80 90

Fig. 1. Time-course of diuresis (mean total weight loss) in females after a blood meal
on chicken by uninfected (-) and infected (--) Aedes aegypti susceptible (e) and refrac-
tory (0) to Dirofilaria immitis.

1987). For infected susceptible Ae. aegypti, lower rates of diuresis were observed as
the number of developing first stage larvae increased. Similar results were recorded
for infected Ae. taeniorhynchus and An. quadrimaculatus (Nayar & Bradley 1987).
However, in infected refractory Ae. aegypti females the slower rate of diuresis observed
could not be related to the number of moribund prelarvae. The impaired rate of diuresis
in infected mosquitoes could be due to the damage caused to Malpighian tubules by
moribund prelarvae in refractory females and developing first stage larvae in the sus-
ceptible females. In Ae. taeniorhynchus infected with D. immitis prelarvae, the ultra-
structure of the Malpighian tubule cells 48 h after the infective blood meal showed
significant reduction in microvillar volume, in the percent of microvillar volume occupied
by mitochondria and in volume of mitochondria within the microvilli when compared to
the uninfected Malpighian tubule cells (Bradley et al. 1984). Palmer et al. (1986) con-

December, 1989

Mahmood & Nayar: Filarial Infection of Aedes aegypti 583





.0 0 1 I I
0 20 40 60 80 100



0.0 i ---i-- -
0 20 40 60 80 100

Fig. 2a. Effect of the increasing number of developing larvae of Dirofilaria immitis
on the total loss in weight during diuresis in infected susceptible female of Aedes
Fig. 2b. Effect of the increasing number of arrested prelarvae on the total loss in
weight during diuresis in refractory Aedes aegypti.






1.0 Or

584 Florida Entomologist 72(4) December, 1989

firmed these findings in Ae. aegypti infected with D. immitis, and further showed, that
when first stage larvae were ready to molt 6 days after the infective blood meal, the
cytoplasmic ground substance was highly disrupted and the cells appeared to be greatly
inflated. These authors further concluded that, during the development of D. immitis
larvae through the first stage, they completely destroy the Malpighian tubule cells in
which they reside and after molting, the second stage larvae move to the lumen of the
Malpighian tubules. They also suggested that large worm burdens could be responsible
for the destruction of the excretory system and vector mortality.
In another study, Bradley & Nayar (1984) examined the rate of fluid excretion, in
vitro, using both uninfected and infected D. immitis Malpighian tubules of Ae.
taeniorhynchus and demonstrated that the tubules showed a decline in transport with
time following infection and the reduction in transport capacity was proportional to the
number of D. immitis larvae infecting the Malpighian tubules. A similar phenomenon
could be occurring in the infected susceptible A. aegypti females. In infected refractory
Ae. aegypti females, damage to several Malpighian tubule cells inhabited by moribund
prelarvae was previously observed (Nayar & Sauerman 1975) and probably is the cause
of the reduced rate of diuresis seen in this study.


This study was supported by a grant from the NIH, NIAID AI-17736. This manu-
script is from a thesis submitted to the Graduate School of the University of Florida in
partial fulfillment of the requirements for the M. S. degree of Farida Mahmood.
University of Florida, Institute of Food and Agricultural Sciences, Experiment Sta-
tions Journal Series No. 7877.


BOORMAN, J. P. T. 1960. Observations on the feeding habits of the mosquito Aedes
(Stegomyia) aegypti (Linnaeus): the loss of fluid after a blood meal and the
amount blood taken during feeding. Ann. Trop. Med. Parasitol. 54: 8-14.
BRADLEY, T. J., AND J. K. NAYAR. 1984. The effect of infection with Dirofilaria
immitis (dog heartworm) on fluid secretion rates in the Malpighian tubules of
the mosquitoes Aedes taeniorhynchus and Anopheles quadrimaculatus. J. Insect
Physiol. 30: 737-742.
BRADLEY, T. J., D. M. SAUERMAN, JR., AND J. K. NAYAR. 1984. Early cellular
responses in the Malpighian tubules of the mosquito Aedes taeniorhynhus to
infection with Dirofilaria immitis (Nematoda). J. Parasitol. 70: 82-88.
KARTMAN, L. 1953. Factors influencing infection of the mosquito with Dirofilaria
immitis (Leidy 1856). Exp. Parasitol. 2: 27-28.
MAHMOOD, F., AND J. K. NAYAR. 1989. Effects of Dirofilaria immitis (Nematoda:
Filarioidea) infection on the life table characteristics of susceptible and refractory
strains of Aedes aegypti (Vero Beach) (Diptera: Culicidae). Florida Entomol. 72:
Inheritance of susceptibility to Dirofilaria immitis infection in Aedes aegypti.
Ann. Trop. Med. Parasitol. 68: 97-109.
NAYAR, J. K., AND T. J. BRADLEY. 1987. Effects of infection with Dirofilaria im-
mitis on diuresis and oocyte development in Aedes taeniorhynchus and
Anopheles quadrimaculatus (Diptera: Culicidae). J. Med. Entomol. 24: 617-622.
NAYAR, J. K., AND D. M. SAUERMAN. 1975. Physiological basis of host susceptibility
of Florida mosquitoes to Dirofilaria immitis. J. Insect Physiol. 21: 1965-1975.
NIJHOUT, H. F., AND G. M. CARROW. 1978. Diuresis after a blood meal in female
Anopheles freeborni. J. Insect Physiol. 24: 293-298.

Ali et al.; Bacillus Effectiveness 585

PALMER, C. A., D. D. WITTROCK, AND B. M. CHRISTENSEN. 1986. Ultrastructure
of Malpighian tubules of Aedes aegypti infected with Dirofilaria immitis. J.
Invertebr. Pathol. 48: 310-317.
STOBBART, R. H. 1977. The control of diuresis following a blood meal in females of
yellow fever mosquito Aedes aegypti (L.). J. Exp. Biol. 69: 53-85.
TAYLOR, E. R. A. 1960. The development of Dirofilaria immitis in the mosquito
Aedes aegypti. J. Helminthol. 34: 27-28.
changes in flow rate and composition of urine during the post-blood meal diuresis
in Aedes aegypti (L.). J. Comp. Physiol. 153: 257-265.


University of Florida, IFAS, Central Florida Research and Education Center
2700 East Celery Avenue, Sanford, FL 32771-9608

Lake County Mosquito and Aquatic Plant Management, 401 South Bloxham Avenue
Tavares, FL 32778


A wettable powder (WP) formulation of Bacillus sphaericus 2362 (ABG-6232) and
an aqueous suspension of Bacillus thuringiensis serovar. israelensis (Vectobac 12 AS)
were evaluated against Culex mosquitoes in a dairy wastewater lagoon in central
Florida. Culex nigripalpus and Cx. quinquefasciatus inhabited the lagoon; the former
species comprised >90% of the total Culex larvae collected during the sampling periods.
Vectobac 12 AS (at 1.17 L/ha) and ABG-6232 (at 1.12 kg/ha) were each applied sepa-
rately to the lagoon on three different occasions during 1987-1988. Vectobac 12 AS
caused a maximum 71-88% larval reduction for only one day posttreatment in the three
treatments. ABG-6232 (WP) gave an average larval reduction of 84-92% in the three
tests for up to 13 days posttreatment with >50% average reduction of the larvae being
maintained for beyond 17 days posttreatment.


Se evalu6 una formulaci6n de polvo humectante de Bacillus sphaericus 2362 (ABG-
6232) y una suspension acuosa de Bacillus thuringiensis serovar. israelensis (Vectobac
12 AS) contra mosquitos Culex en una laguna de agua de desperdicio de una lecheria
en el centro de la Florida. Culex nigripalpus y Cx. quinquefasciatus habitaban la
laguna; la primera especie constituia >90% del total de larvas de Culex colectadas
durante el period de muestreo. Vectobac 12 AS (a 1.17 L/ha) y ABG-6232 (a 1.12 kg/ha)
fueron separadamente aplicados a la laguna en 3 ocasiones diferentes durante 1987-1988.
Vectobac 12 AS caus6 una reducci6n mAxima de larvas de 71-88% solo un dia despu6s

586 Florida Entomologist 72(4) December, 1989

del tratamiento en los tres tratamientos. ABG-6232 caus6 un promedio de reducci6n de
larvas de 84-92% en las tres pruebas hasta 13 dias despues del tratamiento con un
promedio de >50% de reducci6n de larvas mantenidas por mas de 17 dias despu6s del

Wastewater generated on a daily basis at dairy farms, primarily through washing
dairy herds and milking barns, collects into large open retention ponds or lagoons. The
impounded water contains high contents of solid and dissolved organic materials, provid-
ing ideal conditions for mosquito oviposition and larval development.
In the southeastern United States, the dominant species of mosquito in wastewater
ponds and lagoons is usually Culex quinquefasciatus Say (Steelman & Colmer 1970,
Rutz & Axtell 1978, O'Meara & Evans 1983). However, in some wastewater systems
in south Florida, Cx. nigripalpus Theobald is more abundant than Cx. quinquefasciatus
(Carlson 1982); the former species is the dominant summer and early fall Culex in
peninsular Florida (Edman 1974).
In Florida, as in many other parts of the United States, the dairy industry is being
encroached upon by rapid urbanization. This results in increasing human contact with
mosquitoes breeding in and around the dairy environments and necessitating mosquito
Two bacterial agents, Bacillus thuringiensis serovar. israelensis (B.t.i.) and B.
sphaericus, in a number of laboratory and field studies have proven to be excellent
larvicides of a variety of mosquito species world-wide (Ali et al. 1981, Ali & Nayar 1986,
Davidson et al. 1981, Lacey et al. 1984, Majori et al. 1987, Mulligan et al. 1980, World
Health Organization 1985). For the past several years, B.t.i., in a variety of formula-
tions has been marketed for mosquito control in most parts of the world. However, it
has been documented that B. sphaericus, in general, is more toxic (equal potency basis)
to some mosquito species than B.t.i., and also has the advantage of longer persistence
in the treated habitats (DesRochers & Garcia 1984, World Health Organization 1985).
As a consequence, B. sphaericus is presently being enthusiastically developed by the
chemical industry as a mosquito larvicide.
This study reports the effectiveness of an experimental wettable powder (WP) of B.
sphaericus strain 2362 (ABG-6232) against Culex spp. larvae in a dairy lagoon in central
Florida. A commercial aqueous suspension of B.t.i. (Vectobac 12 AS) was also tested
in the same lagoon to compare the degree and longevity of control given by the two
microbial mosquito larvicides.


The dairy lagoon, rectangular in outline, located at approximately 28 53' N latitude
and 810 41' W longitude, in Dona Vista, Lake County, Florida, was used for this study.
It is 102 m long and 15 m wide, with an average water depth of 1 m. The lagoon receives
wastewater effluent daily (through gravity flow) from approximately a 400-cow dairy
operation via a series of two small settling ponds (each ca. 8 x 8 m). The ponds retain
the bulk of the solids which are allowed to dry through evaporation and percolation and
periodically cleaned by dredging. The impounded water in the lagoon is occasionally
pumped out for pasture irrigation.
Water in the lagoon is usually highly turbid (>100 NTU) and almost neutral (pH
6.9). The lagoon is lined with a thick natural growth of cattails (Typha spp.) and water-
primrose (Ludwigia spp.). Some grasses also border the lagoon. The predominant float-
ing vegetation on the lagoon water consists of Giant duckweed (Spirodela polyrhiza)
and Pennywort (Hydrocotyle ranunculoides).

Ali et al.; Bacillus Effectiveness

The B.t.i. and B. sphaericus used in this study were produced and provided by
Abbott Laboratories, N. Chicago, IL. On three separate occasions (October 5, 1987,
November 16, 1987, and May 31, 1988), the WP ABG-6232 (812 ITU/mg, lot no. 08-083-
BR) was uniformly applied from a boat to the entire surface of the lagoon at a rate of
1 lb/acre (1.12 kg/ha). Similarly, Vectobac 12 AS (1200 ITU/mg, lot no. 15-179-BA)) was
applied to the lagoon on October 26, 1987, June 20, 1988, and July 7, 1988, at a rate of
1 pt/acre (1.17 L/ha). For each treatment the required amount of spray material was
thoroughly mixed with about 3 gal (11.4 L) of water in a bucket and transferred to and
applied with a 3.5 gal (13.25 L) pressurized spray can (Solo Backpak) (Solo, Inc. New-
port News, VA). A max.-min. thermometer was used at one location in the lagoon to
record the water temperature range during each field test.
Immediately prior to and periodically after each treatment, samples of mosquito
larvae were collected from the sides of the lagoon at 14 predetermined locations using
a 500-ml dipper. The middle area of the lagoon was also sampled from a boat on two
occasions but no mosquito larvae were found in the open water. Since there was no
comparable habitat in the area to use for an untreated control, the posttreatment larval
declines had to be compared with the corresponding prevailing pretreatment population
levels to elucidate the percent larval reductions and effectiveness of each treatment.
The two small retention ponds containing mostly solids or sludge supported insufficient
numbers of mosquito larvae and could not be used as controls. The larval samples were
brought to the laboratory for taxonomic identifications and counting.


Larvae of Cx. nigripalpus and Cx. quinquefasciatus inhabited the lagoon with the
former species comprising over 90% of the total larvae on each sampling occasion. The
mean number of larvae per dip during the B. sphaericus 2362 (ABG-6232) treatments
exceeded 350 larvae at the time of pretreatment on each occasion (Table 1). ABG-6232
at 1.12 kg/ha rate of application produced 64-97, 38-93, and 60-85% reductions of larvae
for beyond two weeks (14-17 days) in the treatments 1, 2, and 3, respectively. Overall,
ABG-6232 gave larval reductions of 84-92% in the three treatments (combined) for up
to 13 days, and a greater than 50% reduction of pretreatment larval numbers was
maintained for beyond 17 days. The cumulative trend of larval populations and their


Mean no. Percent larval reduction posttreatment (days)
pretreatment 2-5 6-9 10-13 14-17

Treatment 1 (October 5, 1987)C
498 94 97 96 64
Treatment 2 (November 16, 1987)d
363 81 93 77 38
Treatment 3 (May 31, 1988)e
430 76 85 81 60

a812 ITU/mg
bMixture of Cx. nigripalpus and Cx. quinquefasciatus (>90% Cx. nigripalpus).
eWater temperature: 21-24C; d17-23sC; e21-28C.

588 Florida Entomologist 72(4) December, 1989

declines due to the three B. sphaericus treatments combined are shown in Fig. 1. In
the pretreatment samples, 3rd and 4th instar larvae were predominant but after the
treatments, mature larvae (3rd and 4th instars) declined considerably while the young
larvae (1st and 2nd instars) predominated for more than two weeks posttreatment. The
prevalence of the young larvae was probably due to their continuous addition as a result
of continuous oviposition and egg hatching in the lagoon. These larvae were not exposed
to the pathogen for sufficient time to suffer mortality. A similar field observation on
asynchronously developing mosquito larvae exposed to B. sphaericus was reported by
Majori et al. (1987).
Vectobac 12 AS at 1.17 L/ha rate of treatment produced a maximum of 71% (treat-
ment 1), 88% (treatment 2), and 83% (treatment 3) reduction of mosquito larvae within
a day after each treatment (Table 2). In treatment 1, the number of larvae was reduced
by 14-67% for up to 3 days. In treatment 2, 16-33% reductions of the larval numbers
were recorded during the 2-4 days of posttreatment sampling, while in treatment 3, the
larval populations returned to the pretreatment levels within 2 days. Overall, for the
three treatments combined, B.t.i. induced a maximum larval reduction of 84% in one
day posttreatment and <36% after 2 days. Third and 4th instar larvae were reduced
considerably after the treatments but 1st instar larvae, due to their continuous recruit-
ment, predominated during the pre-, and posttreatment periods (Fig. 1).
This study suggests that appreciable larval reduction (84%) of Cx. nigripalpus and
Cx. quinquefasciatus provided by B.t.i. (Vectobac 12 AS) at 1.17 L/ha in the dairy
wastewater lasted only for one day posttreatment. Although Vectobac 12 AS had a
higher ITU/mg (1200) as compared to the 812 ITU/mg for B. sphaericus 2362 (ABG-
6232), on equal wt/vol basis, Vectobac 12 AS appeared to produce slightly lower levels
of larval control and for a much shorter time than ABG-6232. These data on B.t.i. are
compatible with some previous mosquito control studies in polluted waters where B.t.i.
in different formulations had caused 91-100% larval reductions of Cx. quinquefasciatus
for 1-3 days after treatments at rates ranging from 0.65 to 5.6 kg/ha (Majori et al. 1987).
Also, Mulla et al. (1982) reported Cx. quinquefasciatus larval reductions of 0, 81 and
91% one day after treatment with Bactimos (WP, 3500 ITU/mg) applied at 0.56, 1.12,
and 2.24 kg/ha, respectively, to dairy lagoons in southern California.
The field activity of some potent strains of B. sphaericus (including strain 2362)
against larvae of a large number of mosquito species in different parts of the world has


Mean no. Percent larval reduction posttreatment (days)
pretreatment 1 2 3 4

Treatment 1 (October 26, 1987)C
111 71 67 14 0
Treatment 2 (June 20 1988)d
410 88 30 33 16
Treatment 3 (July 7, 1988)"
41 83 0 0

"1200 ITU/mg
bPredominantly Cx. nigripalpus (Cx. quinquefasciatus <5%)
eWater temperature: 19-240C; d21-27C; '21-28'C.

Ali et al.; Bacillus Effectiveness

2 3 4 5 6 7

9 10 11 12 13 14 15 16 17


0 1 2 3 4
Fig. 1. Pre-, and posttreatment larval trends of Culex spp. (predominantly Cx.
nigripalpus) in a dairy wastewater lagoon treated at 1.12 kg/ha with a wettable powder
formulation of Bacillus sphaericus strain 2362 (ABG-6232), and at 1.17 L/ha with an
aqueous suspension of Bacillus thuringiensis serovar. israelensis (Vectobac 12 AS),
Dona Vista, Lake County, central Florida, 1987-1988.


Florida Entomologist 72(4)

December, 1989

been documented (World Health Organization 1985). A flowable concentrate (BSP-1,
containing 12% primary powder of strain 2362) applied at 20 g/m2 provided a satisfactory
control of Cx. quinquefasciatus for 6 to 10 weeks in cesspits and latrines in the United
Republic of Tanzania, while a WP of B. sphaericus 2362 applied at 0.25 kg/ha produced
90% larval reduction of Cx. quinquefasciatus in polluted waters in Ivory Coast (World
Health Organization 1985). Recent studies of Mulla et al. (1988) in dairy wastewater
lagoons in California indicated that two primary powder preparations of B. sphaericus
(ABG-6184) at rates of 0.26 and 0.56 kg/ha gave mediocre and short-term control of
Culex mosquitoes (Cx. peus and Cx. quinquefasciatus). However, the level of control
and persistence greatly increased as the dosages were increased to 1.12, 2.24, and 4.48
kg/ha. The lower two rates yielded almost 100% control for 4 weeks while the 4.48 kg/ha
rate yielded control (99%) for up to 49 days or longer. A flowable concentrate prepara-
tion of B. sphaericus (BSP-2) yielded complete initial and persistent control of Culex
larvae for 14-21 days at 2.24, 4.49. and 5.6 kg/ha rates of treatment.
The present study confirms the superiority of B. sphaericus 2362 over B.t.i. in
controlling Culex mosquitoes in polluted waters. Only one treatment rate (1.12 kg/ha)
of B. sphaericus was employed in this study; higher rates of this microbial mosquito
larvicide may produce better initial and longer-lasting control as shown by the studies
of Mulla et al. (1988). The increased application rates) of B. sphaericus is feasible and
justified in view of the long-lasting control obtained with one treatment, which would
save on the costs of site inspections and repeated treatments when less potent and less
persistent larval control agents are employed (Mulla et al. 1988). Thus, rapid develop-
ment of B. sphaericus leading to its availability for commercial use in mosquito control
programs is deemed necessary.


The assistance of Columbus Burke, Sr., during the course of this study is ap-
preciated. This is Florida Agricultural Experiment Stations Journal Series No. 10048.
Mention of a pesticide or a commercial proprietary product does not constitute an en-
dorsement or recommendation by the University of Florida, nor does it imply registra-
tion under FIFRA as amended.


ALI, A., AND J. K. NAYAR. 1986. Efficacy of Bacillus sphaericus Neide against
larval mosquitoes (Diptera: Culicidae) and midges (Diptera: Chironomidae) in the
laboratory. Florida Entomol. 69: 685-690.
ALI, A., R. D. BAGGS, AND J. P. STEWART. 1981. Susceptibility of some Florida
chironomids and mosquitoes to various formulations of Bacillus thuringiensis
serovar. israelensis. J. Econ. Entomol. 74: 672-677.
CARLSON, D. B. 1982. Mosquitoes associated with evaporation-percolation ponds in
Indian River County, Florida. Mosq. News 42: 244-250.
DAVIDSON, E. W., A. W. SWEENEY, AND R. COOPER. 1981. Comparative field trials
of Bacillus sphaericus strain 1593 and Bacillus thuringiensis serovar. israelensis
commercial powder. J. Econ. Entomol. 74: 350-354.
DESROCHERS, B., AND R. GARCIA. 1984. Evidence for persistence and recycling of
Bacillus sphaericus. Mosq. News 44: 160-165.
EDMAN, J. D. 1974. Host-feeding patterns of Florida mosquitoes. III. Culex (Culex)
and Culex (Neoculex). J. Med. Entomol. 11: 95-104.
LACEY, L. A., M. A. URBINA, AND C. M. HEITZMAN. 1984. Sustained release
formulations of Bacillus sphaericus and Bacillus thuringiensis (H-14) for the
control of container-breeding Culex quinquefasciatus. Mosq. News 44: 26-32.


Haack et al.: Dominican Pine Bark Beetles 591

MAJORI, G., A. ALI, AND G. SABATINELLI. 1987. Laboratory and field efficacy of
Bacillus thuringiensis var. israelensis and Bacillus sphaericus against
Anopheles gambiae S.L. and Culex quinquefasciatus in Ouagadougou, Burkina
Faso. J. Am. Mosq. Control Assoc. 3: 20-25.
MULLA, M. S., B. A. FEDERICI, AND H. A. DARWAZEH. 1982. Larvicidal efficacy
of Bacillus thuringiensis serotype H-14 against stagnant water mosquitoes and
its effect on nontarget organisms. Environ. Entomol. 11: 788-795.
cacy and longevity of Bacillus sphaericus 2362 formulations for control of mos-
quito larvae in dairy wastewater lagoons. J. Am. Mosq. Control Assoc. 4: 448-
MULLIGAN, F. S., C. H. SCHAEFER, AND W. H. WILDER. 1980. Efficacy and persis-
tence of Bacillus sphaericus and B. thuringiensis H-14 against mosquitoes under
laboratory and field conditions. J. Econ. Entomol. 73: 684-688.
O'MEARA, G. F., AND F. D. S. EVANS. 1983. Seasonal patterns of abundance among
three species of Culex mosquitoes in a south Florida wastewater lagoon. Ann.
Entomol. Soc. Am. 76: 130-133.
RUTZ, D. A., AND R. C. AXTELL. 1978. Factors affecting production of the mosquito,
Culex quinquefasciatus (=fatigans) from anaerobic animal waste lagoons. N. C.
Agric. Exp. Stn. Tech. Bull. 256-1-32.
STEELMAN, C. D., AND A. R. COLMER. 1970. Some effects of organic wastes on
aquatic insects in impounded habitats. Ann. EntQmol. Soc. Am. 63: 397-400.
WORLD HEALTH ORGANIZATION. 1985. Informal consultation on the development of
Bacillus sphaericus as a microbial larvicide. W. H. 0. mimeo. doc., WHO/TDR/


'USDA Forest Service, North Central Forest Experiment Station
1407 South Harrison Road, East Lansing, Michigan 48823
"Texas Forest Service, P.O. Box 310, Lufkin Texas 75901
3German Development Service, San Jos6 de las Matas, Dominican Republic


An outbreak of pine bark beetles (Coleoptera: Scolytidae) occurred in the central
highlands of the Dominican Republic during 1986-1987. Initiation of the outbreak coin-
cided with a period of severe drought. Thousands of native West Indian pines, Pinus
occidentalis Sw., were killed by beetles attacking the trunk and branches. Ips callig-
raphus (Germar) was the principal mortality agent. Two other bark beetles infested the
smaller branches (Pityophthorus antillicus Bright) and shoots (Pityophthorus
pinavorus Bright). Spatial attack pattern, harem size, egg gallery length, egg density,
and sex ratio of Dominican I. calligraphus populations were similar to values reported
from the southeastern United States. However optimal pheromone blends differed be-
tween the two populations. Of five pheromone blends tested, the 50% (-)-ipsdienol:50%
(+)-ipsdienol plus cis-verbenol attracted the most Dominican beetles. Ips calligraphus
adults were collected throughout the year in pheromone-baited traps and theoretically
could complete 11 to 12 generations per year in the Dominican highlands. No other
species of Ips nor any species of Dendroctonus were collected in traps baited with
pheromones of the pine bark beetle complex of the southeastern United States. Average
tree diameter, tree height, and stand basal area from several infestation sites are pre-
sented. Infested pines ranged from 5 to 50 cm in diameter and from 6 to 26 m in height.

Florida Entomologist 72(4)

December, 1989


Un brote del escarabajo de la corteza de pinos (Cole6ptera: Scolytidae) ocurri6
en las tierras altas centrales de la Repdblica Dominicana durante 1986-87. El comienzo
del brote coincidi6 con un period de seca severe. Miles de pinos de la Indias Occiden-
tales, Pinus occidentalis Sw., fueron matados por los escarabajos atacando el tronco y
las ramas. El principal agent de mortalidad fu6 Ips calligraphus (Germar). Otros dos
escarabajos infestaron las ramas mas pequefas (Pityophthorus antillicus Bright) y los
brotes (Pityophthorus pinavorus Bright). El patr6n espacial del ataque, el tamaflo del
harem, el largo de la galeria de los huevos, la densidad de los huevos, y la proporci6n
del sexo de los huevos de la poblaciof Dominicana de I. calligraphus fum similar a los
valores reportados del sudeste de los Estados Unidos de Am6rica. Sin embargo, mezclas
6ptimas de feromonas fueron distintas entire las dos poblaciones. De cinco mezclas de
feromonas probadas, el 50% (-)-ipsdienol:50% (+)-ipsidenol mas cis-verbenol atrajo mas
escarabajos Dominicanos. Se colectaron adults de Ips calligraphus durante el afio en
trampas cebadas con feromonas y te6ricamente pudieran completar de 11 a 12
generaciones por afo en las tierras altas Dominicanas. Ninguna otra especie de Ips ni
ninguna otra especie de Dendroctonus se colectaron en trampas cebadas con feromonas
del complejo de escarabajos de la corteza de los pinos del sudeste de los Estados Unidos.
Se present el promedio del diametro y altura de los Arboles, y la base de la poblaci6n
de distintas areas infestadas.

The Dominican Republic occupies the eastern two-thirds of the island of Hispaniola.
It has a mountainous terrain and a maritime tropical climate. The Dominican forests
are classified as pine, hardwood, or mixed pine-hardwood. Using 50% tree crown cover
as a basis, 38% of Dominican land was categorized as forested in 1980. Seventeen
percent of the forested area was planted to pine, 34% was hardwoods, and 49% was
mixed (FAO 1981). These forests aid in controlling erosion and protecting watersheds
as well as producing lumber, firewood, and charcoal. About 75% of the Dominicans
utilize charcoal or firewood for cooking (FAO 1987). During the past several decades,
many forests have been lost to uncontrolled cutting, wildfire, hurricanes, and conversion
to agriculture (Hartshorn et al. 1981). To limit the rate of deforestation, the Dominican
government in 1967 closed all private lumber mills and prohibited cutting trees without
a permit. Reforestation efforts have been modest, planting about 6200 ha between 1969
and 1984; the principal species planted were West Indian pine, Pinus occidentalis Sw.
(Dominican sources), and Caribbean pine, P. caribaea Morelet (from Belize and Hon-
duras) (CRIES 1984, FAO 1987).
From late 1986 through mid-1987, an outbreak of bark beetles (Coleoptera:
Scolytidae) occurred in the pine forests of the Dominican Republic, killing thousands of
native P. occidentalis trees. Initiation of the outbreak coincided with severe drought
conditions. Infestations occurred primarily in the central highlands of the Cordillera
Central where 84% of the country's pine forests occur (CRIES 1984).
Objectives of the present study were to: (1) determine the principal bark beetle
species infesting P. occidentalis, (2) collect life-history data on each bark beetle species,
and in particular compare the Ips data with published reports from the southeastern
United States to determine if the island population differs substantially from those on
the mainland, and (3) gather P. occidentalis tree and stand data from the outbreak sites.

Background Information

The most severe bark beetle infestations occurred in forests administered by Plan
Sierra, which is a regional program with headquarters in San Jos6 de las Matas, Pro-
vince of Santiago. Initiated in 1979, Plan Sierra is mandated to develop and integrate

Haack et al.: Dominican Pine Bark Beetles 593

into the national economy a mountainous region covering about 200,000 ha in Santiago
and Santiago Rodriguez Provinces. The forestry component of Plan Sierra provides for
harvesting and management of the natural forests as well as for reforestation. Plan
Sierra has mapped, inventoried, and prepared forest management plans for more than
3000 ha of pine forests under its jurisdiction (Kastberg 1982).
Few published reports exist on P. occidentalis, which is native only to the islands
of Hispaniola and Cuba. In the Dominican Republic, where it is the only native pine, it
grows on poor sites at elevations from 800 to more than 3000 m (Critchfield & Little
1966, Hartshorn et al. 1981). In Cuba, it occupies dry, rocky sites at elevations from
900 to 1500 m; individual trees reach 102 cm in diameter at breast height (DBH, 1.4 m
above groundline) and 41 m in height (Smith 1954).
Species of both six-spined and five-spined Ips bark beetles have been reported from
the Dominican Republic. However, much taxonomic confusion still exists over the actual
species present. For example, the six-spined I. interstitialis was collected in the
Dominican Republic in 1967 (Lanier 1972). However, the six-spined Ips recovered dur-
ing a 1969-1970 survey of the Dominican forest insect and disease problems were re-
ported as I. calligraphus (FAO 1971). It is possible that both species could occur on the
island of Hispaniola. The taxonomic status of these six-spined Ips is still in debate.
Lanier (1972) recognizes I. interstitialis (Eichhoff), which is distributed from Central
America to southern Arizona, as distinct from I. calligraphus, which is mostly North
American in distribution. However, Wood (1982) place I. interstitialis in synonymy
with I. calligraphus. Similarly, the five-spined Ips grandicollis (Eichhoff) is reported
to occur in the Dominican Republic by Wood (1982) and has been collected from P.
occidentalis in Haiti as well (Billings 1985). However, the taxonomic certainty of these
reports is now in question because all specimens reported as I. grandicollis by Garraway
(1986) from nearby Jamaica were later found to be Ips cribricollis (Eichhoff) by Lanier
(1987). Here too, Wood (1982) placed I. cribricollis in synonymy with I. grandicollis.
However, Lanier (1987) considers these two species as distinct forms, with I. grandicol-
lis being mostly North American in distribution and I. cribricollis being mostly from
Central America.
No specimens of Dendroctonus bark beetles, which are important pests in Central
and North America, have been recovered from the Dominican Republic or any other
Caribbean island to our knowledge. Two other bark beetle species in the genus
Pityophthorus infest P. occidentalis in the Dominican Republic: Pityophthorus antil-
licus Bright (Bright 1981) and Pityophthorus pinavorus Bright (Bright 1985).


Eight major outbreak areas between 400 and 1000 m of elevation were visited in the
Provinces of Santiago and Santiago Rodriguez during a 2-week period in November
1987 and a 1-week period in April 1988. Several insect, tree, stand, and site characteris-
tics were recorded at each site. At each location, three to five beetle-killed trees were
inspected from the groundline to the ends of several branches to determine the bark
beetle species present. Beetle specimens were collected and identified, and notes were
taken on the egg galleries of each species. For the Ips species encountered, we measured
the distance between male attack sites, harem size, egg gallery length, and egg density
(see details on methods in Haack et al. 1987). The adult sex ratio was calculated from
specimens reared from infested trees and from beetles caught in pheromone traps.
The seasonal occurrence of I. calligraphus was monitored near San Jose de las
Matas from October 1986 through September 1987 using 18 "stove pipe" traps. The
traps were made of 20-cm-diameter, white PVC pipe, that was cut into 1-m lengths and
drilled with more than 100 holes each. Traps were capped to exclude rain, fitted with

594 Florida Entomologist 72(4) December, 1989

a water-filled container in the bottom to capture beetles, and suspended vertically. A
pheromone lure, containing a racemic mixture of ipsdienol (Celamerck Inc., Ingelheim,
Germany), was placed inside each trap and changed monthly. In general, beetles were
collected and counted weekly.
In November 1987, a test was conducted to determine what blend of the two
ipsdienol enantiomers was most attractive to the local population of six-spined Ips (later
determined to be I. calligraphus). Ipsdienol and cis-verbenol are thd two major compo-
nents of the aggregation pheromone of I. calligraphus (Renwick & Vit6 1972, Vite et
al. 1978). The six treatments were: 2% (+):98% (-), 25% (+):75% (-), 50% (+):50% (-),
75% (+):25% (-), 98% (+):2% (-), and a blank ethanol control. All mixtures were
prepared with the same amounts of total ipsdienol (8 mg) and cis-verbenol (8 mg). The
pheromones were diluted in ethanol to a quantity of 110 R1 and deployed in closed,
polyethylene vials (release rate ca. 34 pLgm/day at 22'C). Twenty-four sticky traps (51
cm by 66 cm; DeWill Inc., Chicago, Illinois) were installed near San Josd de las Matas,
six in each of four locations. At every location each treatment was assigned to one of
the six traps. The total number of I. calligraphus adults on each trap was recorded
after eight days.
In April 1988, a second pheromone study was conducted in the same outbreak region
to determine if any of the other major bark beetle species common to the pine forests
of the southern United States were present, i.e., Dendroctonusfrontalis Zimmermann,
I. calligraphus, I. grandicollis, and I. avulsus (Eichhoff). Multiple-funnel barrier traps
(Phero-Tech Inc., Vancouver, British Columbia) were baited with a combination of
pheromones specific to these four beetle species [400 pl of frontalin, 250 ml of pine
turpentine, 8 mg of cis-verbenol, 8 mg of racemic ipsenol, and 8 mg of racemic ipsdienol
were deployed in polyethylene vials or tubing; see Borden (1982) for details on
pheromones of each species]. One trap was placed in each of four pine stands near San
Jos6 de as Matas, with each trap being baited with all pheromones. Responding insects
were collected after 5 days and identified.
We collected data on (1) average DBH, height, and basal area of several forest
compartments in which outbreaks occurred [using data from Kastberg (1982)], and (2)
height and diameter measurements of more than 1000 beetle-killed pines from seven
outbreak areas (Plan Sierra, unpublished data). In the region administered by Plan
Sierra, more than 600 forest compartments (covering about 3000 ha) have been de-
lineated and inventoried (Kastberg 1982). These stands are representative of P. occiden-
talis forests in much of the Dominican central highlands. Each forest compartment was
classified into one of four categories by Kastberg (1982): (1) young pine, average DBH
< 8 cm; (2) actively growing pine, average DBH > 8 cm with active height and diameter
growth; (3) mature pine, average DBH > 8 cm, but with little height and diameter
growth, and (4) open stand, average DBH > 8 cm, usually mature trees, basal area
typically < 5 m2/ha.


Outbreak Site Conditions

The outbreak sites ranged in size from several scattered trees to large forested areas
of several hundred hectares. No exact figures are available on the total area affected.
Most pines were attacked and killed during the last quarter of 1986 and the first half
of 1987. Rainfall at San Jos6 de las Matas is usually bimodal (Fig. 1). A severe drought
affected the region during the second half of 1986 and apparently was the principal
environmental stress that initiated the outbreak. In other pine-growing regions of the
country, where drought conditions were mild, outbreaks did not occur. Throughout the

Haack et al.: Dominican Pine Bark Beetles

C 20


R 10
N 5


D 3 2 3 2.0
E 30
R 25- 4.1

S 20-

0 15 159

Fig. 1. Mean monthly rainfall in centimeters (top; vertical bars = 1 standard error
of the mean) and mean daily maximum, mean, and minimum temperatures in C by
month (bottom) for San Jose de las Matas (elevation about 500 m) during the period
1931-1986 (Source: Plan Sierra, unpublished climatological records). The three temper-
atures (along the right margin) represent the mean annual maximum, mean, and
minimum temperatures based on the same data set.

world, outbreaks of pine bark beetles often occur during or soon after periods of drought
(Haack & Mattson 1989, Mattson & Haack 1987).


Florida Entomologist 72(4)

Practically all outbreak sites consisted of mature or nearly mature P. occidentalis
stands; few trees died in stands classified as young pine by Kastberg (1982). In sites
with nearly 100% tree mortality, soils were shallow and coarse textured, and had much
exposed rock. Similarly, bark beetle outbreaks in Central America have been most
severe in overstocked and overmature stands growing on poor soils (Schwerdtfeger
1955, Beal et al. 1964, Yates 1972, Vit6 et al. 1975, Billings 1982, Wilkinson & Haack

Causal Agents and Within-Tree Distribution

The following species of bark beetles were associated with every dead or dying P.
occidentalis tree inspected (N = 32): Ips calligraphus, Pityophthorus antillicus, and
Pityophthorus pinavorus. In all currently infested trees, I. calligraphus appeared to
have attacked before the Pityophthorus species, based on developmental stage and
gallery patterns of the brood.
The three bark beetle species attacked distinct portions of the tree. Ips calligraphus
colonized the entire trunk and branches down to diameters of 4 cm. Pityophthorus
antillicus was found only in the crown where it inhabited branches of 1-5 cm in diameter.
Its gallery system consisted of a central nuptial chamber in the phloem tissue from
which 4-6 gallery arms radiated in a star-shaped pattern, indicating that these beetles
are harem polygynous (see Kirkendall 1983). Bright (1981) states that P. antillicus has
only been recovered from the Dominican Republic. Pityophthorus pinavorus inhabited
the central pith region of foliage-bearing shoots. These beetles entered the twig from
2 to 4 cm distal to the needle-bearing portion of the shoot. This species has been collected
in the Dominican Republic and in Florida where it was found on or in shoots of slash
pine, Pinus elliottii Engelmann (Bright 1985). Such resource partitioning has been
recorded for other complexes of pine bark beetles in the southeastern United States
(Paine et al. 1981, Foltz et al. 1985), Mexico (Perry 1951), Central America (Vit6 et al.
1975, Wilkinson & Haack 1987), and Jamaica (Garraway 1986).
Based on the age distribution of developing brood, I. calligraphus attacked first in
the upper trunk near the base of the crown. Subsequent attacks proceeded upwards
into the crown and downwards along the trunk. In Florida, where I. calligraphus is
typically the first bark beetle to infest slash pine, a similar attack pattern was reported
(Foltz et al. 1985).
In addition to the bark beetles described above, galleries of one or more unidentified
species of sapwood-infesting ambrosia beetles (Scolytidae and/or Platypodidae) were
present along the lower trunk. Possibly these were galleries of Xyleborus volvulus (F.),
a tropical polyphagous species that was frequently collected with pheromone-baited
traps (see below). No gallery systems or brood of any other Ips or any species of
Dendroctonus were observed.

Interpopulational Comparisons

Overall, life history parameters of I. calligraphus were very similar between Carib-
bean and North American populations. For example, the average distance between
male attack sites (nuptial chambers) was 9.7 cm (range: 5-16 cm, N = 104 nuptial
chambers) in the present study, compared with 9.2 cm in Florida (Haack et al. 1987).
Considering each gallery arm to represent one female, I. calligraphus harem size aver-
aged 3.4 females per male (range: 2-5, N = 108 nuptial chambers) in the Dominican
Republic, 2.8 in Jamaica (Garraway 1986), 3.2 in Florida (Haack et al. 1987), and 3.1 in
Texas (Cook et al. 1983). The average length of egg gallery constructed by Dominican
female beetles was 13.7 cm (range: 7-20, N = 364 egg galleries) compared with 13.3 cm

December, 1989

Haack et al.: Dominican Pine Bark Beetles 597

in Florida (Haack et al. 1987). Egg density (eggs per unit length of gallery) values
ranged between 2 to 4 eggs/cm of gallery (N = 364 egg galleries) for Dominican I.
calligraphus populations. These values are similar to reports for Florida populations
(Haack et al. 1984a, 1984b, 1987). Egg density is a rather "plastic" variable, tending to
increase with increasing inner bark (phloem) thickness. Phloem thickness of P. occiden-
talis ranged from 1 to 3 mm, which is similar to the range found in slash pine (Haack
et al. 1984a), the principal host tree of I. calligraphus in Florida. The sex ratio of
emerging brood adults in the Dominican Republic was approximately 1:1 (male:female,
N = 84) whereas the sex ratio of adults collected from pheromone traps was about 1:3
(N = 294) in November 1987 and 1:2.2 (N = 487) in April 1988. Similar values have
been reported from Jamaica (Garraway 1986) and North America (Cook et al. 1983,
Haack et al. 1987, Renwick & Vit6 1972, Vit6 et al. 1978). The small degree of variability
in the above life-history parameters, especially considering that four different pine
species were involved, suggests that these traits are rather fixed and may change only
slowly in discrete populations of I. calligraphus.

Seasonal Flight and Voltinism

Flight of I. calligraphus occurred during every month of the year, with the generally
decreasing trap catches reflecting the overall decline in outbreak severity during the
sampling period (Fig. 2). Year-round flight also occurs in Florida, where a threshold
temperature for I. calligraphus flight was estimated to be about 20C (Haack 1985).
Given a similar threshold temperature for Dominican populations, the warm tempera-
tures at San Jos6 de las Matas (Fig. 1) will obviously support flight throughout the year.


80 -






1986 1987


Fig. 2. Mean daily catch of Ips calligraphus adults per trap by month from October
1986 through September 1987 (N = 102,980 beetles and 18 traps); vertical bars = 1
standard error of the mean.

598 Florida Entomologist 72(4) December, 1989

Florida populations of I. calligraphus complete one generation every 457 degree
days above a threshold temperature of 100C (Haack 1985). Assuming similar thermal
requirements for Dominican Ips and given that the mean annual temperature of San
Jos6 de las Matas is 24.1C (Fig. 1), Dominican Ips could complete more than 11 gener-
ations per year: [(24.1C-10C) 365 days/year]/457 degree-days/generation = 11.3 gener-
ations/year. Given year-round flight and the ability to complete nearly one generation
per month makes this beetle a serious threat to Dominican forests whenever stressed
by such causes as drought, fire, and hurricane damage.

Pheromone Studies

The results from the ipsdienol blend study were similar at all four trapping locations,
and overall more than 60% of the 638 I. calligraphus collected were on traps baited
with the 50% (+)/50% (-) blend (Fig. 3). In studies by Vito et al. (1978) in Texas, nearly
pure (-)-ipsdienol was most attractive. Such a marked difference between these two
populations of I. calligraphus suggests that evolutionary change in pheromone biology
is taking place. Lanier & Burkholder (1974) indicate that such pheromonal changes can
lead to speciation. Similar differences in optimal pheromone blends have been recorded
for Ips pini (Say) populations from the eastern and western parts of its North American
range (Lanier et al. 1972, 1980), as well as for discrete populations in British Columbia
(Miller et al. 1989).
In addition to I. calligraphus being recovered from the sticky traps in the above
study, five species of Buprestidae and two other species of Scolytidae were collected.
The buprestids were: Actenodes bellula Mannerheim, Buprestis hispaniolae Fisher,
Chrysobothris chlorosticta Thomson, Chrysobothris megacephala Laporte & Gory, and
Chrysobothris tranquebarica (Gmelin). The two scolytids were Pityophthorus annec-
tens LeConte and Xyleborus volvulus (F.).
In the multi-species pheromone study only I. calligraphus were recovered (N =
487). That is, no Dendroctonus nor any other Ips species were collected. The existence
of I. cribricollis in the region cannot be ruled out, however, since the components of
its pheromone are not known, and therefore we may not have presented all compounds
necessary to attract it. Furthermore, since the pheromones of I. calligraphus are
slightly inhibitory to I. grandicollis (Borden 1982), we may have repelled members of
the latter species by placing all pheromone baits on the same traps. In addition to
collecting I. calligraphus, one female specimen of Thanasimus dubius (F.) (Coleoptera:
Cleridae), an important bark beetle predator, was captured. However, no individuals
of another Ips predator, Temnochila virescens (F.) (Coleoptera: Trogositidae), were
observed or caught in either of the two pheromone studies.

Host Trees

All infested pines were P. occidentalis. Young plantations of P. caribaea occurred
in the outbreak region, but were not attacked by I. calligraphus. Nevertheless, six-
spined Ips have attacked and killed P. caribaea in Central America (Yates 1972, Billings
1982) as well as other exotic pines in Jamaica (Garraway 1986).
Data on mean DBH, height and basal area for stands in which outbreaks occurred
are presented in Table 1. These stands were visually similar to P. occidentalis stands
throughout the Dominican highlands. Because mean DBH and height were broadly
similar among actively growing, mature, and open pine stands, more than 90% of the
pine forests can be considered nearly mature or mature (Table 1). This type of skewed
age structure probably facilitated the Ips outbreak because older trees are often more
susceptible to bark beetle attack during periods of environmental stress (Mattson &
Addy 1975).

Haack et al.: Dominican Pine Bark Beetles






75:25 50:50 25:75 2:98 CC



Fig. 3. Percent of all I. calligraphus adults (N = 638) collected on pheromone traps
(4 traps/treatment) baited with various blends of (+) and (-)-ipsdienol; vertical bars =
1 standard error of the mean. Means followed by the same letter are not significantly
different at the P<0.05 level (Duncan's multiple range test).

In seven compartments, total height and DBH were recorded for all beetle-killed
pines (N = 1112 trees). In each compartment, almost every tree was killed and thus
the measurements represent nearly a complete census of the seven stands. Frequency
distributions are presented by height and DBH (Fig. 4). Average height and DBH of
these trees were 16 m (range = 6-26 m) and 21 cm (range = 5-50 cm), respectively,
and compare closely with the average values presented for mature pine stands in Table
Ips bark beetles are often considered secondary forest pests in North America,
attacking primarily logging slash and unhealthy trees (Wood & Stark 1968). However,
under circumstances such as widespread drought, I. calligraphus has the potential to


Forest type1
Forest te Stand parameter2
Type (%) DBH (cm) Ht (m) BA (m2/ha) N

Growing pine 39 18 (12-23) b3 15 (10-19) a 12 (6-19) a 33
Mature pine 43 22 (17-27) a 16 (12-20) a 12 (6-18) a 45
Open stand 9 23 (19-28) a 16 (12-22) a 4 (3-5) b 3

'Description for each forest type presented in text. Area values from Kastberg (1982) as a percent of all forested
lands classified as pine.
2DBH = diameter at breast height, Ht = height, BA = basal area, N = number of stands sampled.
'Overall means are given followed by the range of individual stand means in parentheses. Means followed by the
same letter (within columns) are not significantly different at the P<0.05 level (Duncan's multiple range test).

20 -


Florida Entomologist 72(4)

December, 1989

4 6 8 10 12 14 16 18 20 22 24 26

8 12 16 20 24 28 32 36 40 44 48 52

Fig. 4. Height (top) and diameter (bottom) distributions of Ips-killed Pinus occiden-
talis trees (N = 1112) (Source: Plan Sierra, unpublished sawmill records).

reach outbreak proportions as it did in Jamaica following a drought in 1980 (Garraway
1986) and as reported in the present study.


The authors wish to thank the U.S. Agency of International Development and
Partners of the Americas for foreign travel support; Plan Sierra for lodging and local










Haack et al.: Dominican Pine Bark Beetles 601

travel; Jose Gonzales, Luis Mendosa, Luis Tejada, Jos6 Dominguez, and Teresa Gil of
Plan Sierra for technical and field assistance; Bertil Kastberg of Swedforest Consulting
for providing forest inventory data; Stephen Teale (State University of New York,
Syracuse) and Phero-Tech Inc., Vancouver, British Columbia, for donating pheromone
lures; DeWill Inc., Chicago, Illinois, for donating the sticky traps; Stanley Wellso
(USDA at Purdue University, West Lafeyette, Indiana) for identifying the Buprestidae;
Gerald Lanier (State University of New York, Syracuse) for identifying the Ips; Thomas
Atkinson (University of Florida, Gainesville) for identifying the Pityophthorus and
Xyleborus; and Gerald Lanier and Robert Wilkinson (University of Florida, Gainesville)
for their critical reviews of an earlier draft of this manuscript. Mention of a commercial
or proprietary product does not constitute an endorsement by the U.S. Department of
Agriculture. Voucher specimens of the Scolytidae have been deposited with the Florida
Division of Plant Industry, Gainesville.


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Peck: Introductionw-Insects of the Florida Keys 603

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Department of Biology, Carleton University
Ottawa, Ontario K1S 5B6 Canada


This paper introduces a series investigating the fauna of selected insect and arthropod
groups occurring in south (subtropical) Florida, especially in the Florida Keys. Charac-
teristics of the region are summarized. Collections were made continuously with malaise
and flight-intercept traps for 1 year or more in 21 hardwood hammock or pineland
habitats, and by other methods. Based on numbers of species of trees and shrubs, a
prediction is made that a conservative total of at least 5,000 insect species should occur
in south Florida. Six generalizations about the insect fauna are suggested for future


Este papel introduce una series que investiga la fauna de grupos selectos de insects
y de artr6podos que ocurren en el sur (subtropical) de la Florida, especialmente en los
Cayos de la Florida. Se sumariza las caracteristicas de la region. Se hicieron colecciones
continues usando trampas "malaise" y de interceptoras de vuelos, por un afio o mas en
habitaciones de "hardwood hammock" o de pino, y tambien por otros m6todos. Basado
en el nilmero de species de Arboles y arbustos, se hace una predicci6n conservadora
de que por lo menos 5,000 species deben de occurrir en el sur de la Florida. Se sugieren
seis generalizaciones para pruebas futuras sobre la fauna de insects.

It has long been realized that southern Florida has a most interesting biota. The
climate is subtropical. The southwest trending string of islands, the Florida' Keys, are

604 Florida Entomologist 72(4) December, 1989

young, and have had a dynamic history. They have experienced several cycles of sub-
mergence and emergence. Their uppermost bedrock limestones and oolites were depo-
sited about 100,000 yr BP, during the late Pleistocene, at the time of high (Sangamon
interglacial) sea levels (Hoffmeister 1974). During the last glacial, about 80,000 to 15,000
yr BP, the Keys were a broadly continuous land mass or land bridge on the southern
end of the Florida submarine shelf, extending out to the Dry Tortugas, 110 km west of
Key West. The present islands were formed over the past 10,000 years as sea levels
rose because of the melting of the continental Wisconsinan glacial ice sheets (Hoffmeister
& Multer 1968, Holmes 1985). During this process the land bridge biota retreated to
the decreasing area of the islands. Much of this biota of south Florida and the Keys is
West Indian in origin. It has mostly arrived by over-water dispersal to south Florida
through rafting, being carried by birds, or by storm winds (Darlington 1938).
The Keys have been important in the development of the equilibrium theory of island
biogeography (e.g. MacArthur & Wilson 1967, Simberloff 1974, 1976a, 1976b, Simberloff
& Wilson 1969, 1970, Wilson & Simberloff 1969). Some recent studies have continued
to investigate the composition and dynamics of the insect faunas of the Keys, notably
the ants (Deyrup et al. 1988) and the scavenging scarab beetles (Peck & Howden 1985).
Many Keys insect records are in the series of volumes "Arthropods of Florida." Important
summaries linking Keys insects and habitats to the biogeography of the rest of Florida
are those of Blanton & Wirth (1979) and Woodruff (1973).
A remarkable growth in human population and activity has occurred in south Florida
in the past 30 years. Much of this has been at the expense of native habitats and their
biotas. Few baseline data are available to document or evaluate change in insect faunas
in south Florida. This is of concern to land managers who must make decisions about
protected lands and habitats under their care and administration. Of the 218 invertebrate
species listed in Franz (1982) as being rare or endangered in Florida, 28 of these are
terrestrial species that occur in the US exclusively in subtropical Florida.
There is a growing tendency to incorporate data from south Florida in discussion of
zoogeography of Caribbean insects. Three authors have done so in the recent book edited
by Liebherr (1988). Donnelly (1988) provides a framework of Antillean geology.
This study was undertaken to investigate the species composition and distribution
of selected groups of insects and other arthropods in native habitats in south Florida,
with the belief that this fauna is still very poorly known.


A variety of collecting methods was employed to sample the insect faunas from 1981
to 1986. Most important was the use of 15 large-area intercept or flight intercept traps,
combined with Townes-style Malaise trap heads (Peck & Davies 1980). These were
operated for a year or more each in 18 native closed canopy hardwood hammock forests
and in 3 open pineland forests from November 1984 to December 1986. The advantage
of these traps is that they can sample insects continuously at all times of day or night
and in all weather conditions. They are most effective for beetles, but other insects are
also caught in the trough below or the trap head above, each of which was filled with
non-evaporating ethylene glycol. The catches of these traps were harvested at 3 month
intervals, at which time supplementary collections were made in the same and additional
sites with UV blacklight traps, by sifting or washing forest litter and soil and placing
the samples in Tullgren extractors, or with baited pitfall traps.
Study sites were predominantly native, closed-canopy, hammock forests or open
pineland forest. Principal study sites are indicated in Figure 1 and 2. These were in the
Metro-Dade Park and Recreation Board system at Old Cutler Hammock, Mattheson
Hammock, and forest in the Charles Deering Estate. Everglades National Park sites

Peck: Introduction--Insects of the Florida Keys 605

were in Royal Palm Hammock, Palma Vista Hammock, and two pineland sites on Long
Pine Key. Sites in the Florida State Park system were forests in Grossman Hammock
in Chekika State Recreation Area, Lignum Vitae Key Botanical Reserve, John Pen-
nekamp Coral Reef State Park, Bahia Honda State Park, and Long Key State Recrea-
tion Area. Sites protected by the US Fish and Wildlife Service were in Key Deer and
Crocodile Lake National Wildlife Refuges on Key Largo, and Watsons Hammock and
Cactus Hammock on Big Pine Key, and Sugarloaf and No Name keys. Other hammock
sites were located in Weiner (1981) and were sampled on Sugarloaf Key, Cudjoe Key,
Fat Deer Key, Key Vaca (Marathon), Middle Torch Key, Big Torch Key, northern Big
Pine Key, and Stock Island Botanical Gardens.


Over the sampling period from 1981 to 1986, an estimated 500,000 insects were
collected at over 50 locations. The results will form a projected series of publications.
It is hoped that other entomological specialists will also contribute to an eventual under-
standing of the south Florida insect fauna, its species composition, origin, and distribu-
tion. Collection residues are available for study by others and are in the collections of
the Canadian National Collection, Biosystemics Research Centre, Agriculture Canada,
Ottawa (Acari and Hymenoptera); Alberta Provincial Museum, Edmonton, Canada
(aculeate Hymenoptera); American Museum of Natural Ifistory, New York (spiders and
Hemiptera); American Entomological Institute, Gainesville, Florida (Ichneumonidae);
and the Field Museum of Natural History, Chicago, Illinois (bulk residues, especially
litter samples and Malaise trap Diptera). Where appropriate, data may be included from
the extensive holdings of the Florida State Collection of Arthropods, DPI, Gainesville,


"West Indian" Biota.

The insect fauna of Florida may be the most diverse of any state or province north
of Mexico. This study investigates selected groups of insects and other arthropods in
south Florida, principally in the native West Indian vegetation of the hardwood ham-
mock forests of south Florida and the Keys. "Hammock" is an Amerindian term applied
in Florida to groups of evergreen hardwood trees having a West Indian distribution
and occurring in distinct "tree islands" surrounded by contrasting vegetation, typically
either pinelands, or swamplands. Hammocks are a feature typical of south Florida. The
ultimate goal of this study is to investigate the biogeographic affinities of the insects
living in habitats dominated by a West Indian flora. It should not be assumed a priori
that all the insects are "West Indian". It has already been found that the scavenging
scarab beetle fauna of south Florida, with 35 species, is predominantly derived from
the temperate North America fauna, but contains two native Caribbean species and
seven species which probably are introduced (Peck & Howden 1985).

How many insect species are in south Florida?

At the start, it is necessary to state that we do not know how large the south Florida
insect fauna is. It has not been catalogued. I do not even know of an estimate for the
size of the insect fauna of Florida as a whole. But it is possible to make an estimate for
south Florida, and it is based on the richness of the flora. The richness of an insect
fauna has both a direct and indirect relationship with the diversity of the flora. The

Florida Entomologist 72(4)

Figs. 1 and 2. Generalized maps of south Florida and the islands of the Florida Keys.
The main chain of the Keys is now connected by a series of highway embankments or
bridges (not shown). The primary sampling localities in this study are indicated on the
maps by the following numbers. All are West Indian hardwood hammock forest unless
otherwise indicated. 1. Matheson Hammock, 9800 Old Cutler Road, South Miami. 2.
Deering Estate Park, 167th St. SW and 72 Ave, South Miami. 3. Old Cutler Hammock,
7900 SW 176th St., South Miami. 4. Grossman Hammock, Chekika State Recreation
Area, 168th St. and SW 237 Ave. 5. Long Pine Key, (open pinelands forest), Everglades
National Park. 6. Royal Palm Hammock (= Paradise Key) (not to be confused with
Royal Palm at Collier Seminole State Park, Monroe County), Everglades National Park.
7. Palma Vista Hammock, 1.5 km NW Royal Palm Hammock, Everglades National
Park. 8. Mahogany Hammock, Everglades National Park. 9. North Key Largo, Section"
35. 10. South Key Largo, John Pennekamp Coral Reef State Park. 11. Lignum Vitae
Key. 12. Long Key. 13. Fat Deer Key. 14. Key Vaca (Marathon, Section 1). 15. Ohio
(= Sunset) Key. 16. Bahia Honda Key. 17. No Name Key. 18. Cactus Hammock, Big
Pine Key. 19. Watsons Hammock, Big Pine Key. 20. Watson Boulevard (open pine-palm
forest), Big Pine Key. 21. No Name Road (Section 4, mangrove-hardwood transition
forest), Big Pine Key. 22. Middle Torch Key. 23. Big Torch Key. 24. Cudjoe Key. 25.
Kitching Hammock (Section 25), Sugarloaf Key. 26. Section 23, Sugarloaf Key. 27.
Stock Island Botanical Garden.


December, 1989

Peck: Introduction-Insects of the Florida Keys 607


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608 Florida Entomologist 72(4) December, 1989

number of insect species dependent on a plant species is partly determined by the size
of the geographic range of the host plant, its general abundance within that range, the
evolutionary time to originate such associations, and the size (structural complexity) of
the host. Trees support more insect species (because they offer more "niches") than do
shrubs, herbs, monocots, or ferns. For instance, a study of insect species found on
angiosperm trees in Britain and European Russia found an average of 109 and 74 species
per tree genus respectively (Southwood 1961).
A plant species in Britain frequently is host to more than 50 insect species (Strong
& Levin 1979, Lawton & Schroder 1977). Few data are available for subtropical lands
or islands. Southwood (1960); summarized data for trees on Hawaii and found from 1.8
to 41 species of insects (averaging 40 species) obligatorily restricted to a single tree
species and a total of from 5.6 to 155 insect species (averaging 123 species) associated
in some way with each tree species. Gagn6 (1979) found at least 162 insect taxa on two
tree species in Hawaii. On the Mediterranean island of Cyprus, Southwood (1961) re-
ported 3.4 species of Heteroptera and Auchenorrhyncha alone per tree species. Stork
(1987) found about 3000 insect species in 10 individual trees in Borneo. Erwin (1983)
estimated around 160 species of canopy beetles specific to a tropical tree species in
Panamanian moist, seasonal forests.
These figures may be too high to apply directly to south Florida. The trees are small.
The canopy of a hardwood hammock seldomly exceeds 25 m in height on the mainland
or 15 m in the Keys. The late Pleistocene history of the area allows inadequate time for
speciation, but abundant time for immigration from the West Indies. Panama represents
a continental tropical seasonal moist forest, famous for its rich insect diversity. Cyprus
and Borheo are large islands and close to surrounding continental (or shelf) source
areas. Hawaii is an exceptionally remote archipelago where much in situ speciation over
more time has enriched the plant-feeding fauna. Simberloff (1976b) examined the ar-
boreal arthropods (mostly insects) of nine mangrove islands in the Keys. Each single-
tree island contained from 12 to 30 species and larger mangrove islands had from 63 to
103 species, from a total pool of about 500 species. But few of these are obligatorily
associated with mangroves [See Strong et al. (1984) for additional discussion of plant-in-
sect interactions].
The subtropical Florida flora contains over 100 genera of native woody plants (Tom-
linson 1980). The insect species pools have not been measured on any of these plants in
subtropical Florida. However, if there were an average of 10 specialist phytophagous
insect species per plant genus, we have a possible species pool of 1,000 native herbivore
insect species in subtropical Florida. This is not an unreasonable estimate based on the
above averages and because sub-tropical mainland faunas are probably more diverse
than those of the temperate mainland or of tropical oceanic islands. The actual number
would be expected to be higher because there are additional generalist plant feeders,
and many additional non-arborescent plant species (65% of the total flora is herbaceous
(Long & Lakela 1971)) which are hosts for additional insects. On top of this is the fact
that more than half of any insect fauna is composed of additional predatory and decom-
poser-scavenger species. This could give a total of some 5,000 insect species, but this
seems conservative because over 6,000 insect species are claimed for Mount Desert
Island, Maine, USA (Proctor 1946). Even if the actual number is more or less than 5,000
the point is that the fauna is probably rich, but very poorly known.

Climate of south Florida.

The most important factor which probably limits the northward distribution of most
of the subtropical insects may be minimum winter temperatures. Tomlinson (1980)
suggests that for most wide-ranging native tropical trees it is the average 12C (54F)

Peck: Introduction--Insects of the Florida Keys 609

January isotherm, which forms a U shaped band extending inland some 20-40 km from
the coast, and running south from Cape Canaveral (= Kennedy) on the east coast and
up the west coast to Tampa. Most of Dade and Monroe counties are within this zone.
The main climatic seasons are a long, hot and wet summer from May to September,
and a dry and cooler winter and spring from November to March. Average maximum
temperatures at Miami are about 32C (90F) and average minimums of around 10C
(50'F) with a record minimum of -2C (27F). Rainfall is seasonal and averages 152 cm
(60 inches) at Miami, and decreases to the southwest along the more arid Keys to 97
cm (38 inches) at Key West, with 80% of the rainfall occurring from May to October.

Patterns of distribution and origin.

Several patterns of species distribution or abundance may be expected to occur in
the insects of south Florida. Many of these should parallel patterns found in the flora.
I accentuate patterns from the flora because its species distributions are well known,
and distributional changes through time are better documented in the fossil record.
Certainly, for the flora, the richest part of the state is the subtropical southern tip,
including the Florida Keys. Here there are 130 species of native trees alone, more than
in any other biogeographic region of the United States or Canada. Of these, 18 (12.5%)
are temperate species, at the southern limits of their distribution, with wider distribu-
tions in the eastern United States. The remaining 112 species (87.5%) are at their
northern distributional limits, and have an otherwise tropical distribution (Tomlinson
1980). Only one of these subtropical Floridian trees is considered to be an endemic:
Acacia pinetorum Hermann. The other tropical species are thought to have originated
outside of Florida and to have dispersed there in the Tertiary or Pleistocene by one of
three routes (Tomlinson 1980).
1. A temperate route. This was from temperate North America and down the Florida
peninsula. Some trees used this route to reach the Caribbean. There is fossil pollen of
Fagus, Nyssa, and Liquidambar from the Oligocene of Puerto Rico (Graham & Jarzen
1969), and Quercus, Rhus, and Fraxinus occur natively in Cuba.
2. A tropical overseas route. This is from the south, across the sea gap of the Straits
of Florida. It accounts for the high proportion of trees with fleshy or otherwise edible
fruits or small seeds and sticky fruits (e.g. Pisonia), all dispersed by birds. Also impor-
tant is dispersal by winds and sea currents of floating or rafting propagules, especially
during tropical storms (Darlington 1938). Caribbean lands were also much more exten-
sive and the sea gaps narrower during the low sea levels accompanying Pleistocene
glacials [see especially Campbell (1978) for emergent Caribbean lands during glacials].
Single recent dispersal events were once suggested by the sole US records of Xanth-
oxylumflavum Vahl., Catesbaea parviflora Sw., and Jacquemontiajamaicensis (Jacq.)
(historical plaque on Bahia Honda Key), but these are now known from other islands
(Long & Lakela 1971).
3. A tropical land route. This is from Central America and Mexico via the Gulf
States. It was most important in earlier epochs, and the species usually differentiated
in Florida after dispersal. This route may account for the presence of Diospyros and
Asimina (paw-paw) as relicts in Florida. Comparatively little information is available
on the ancestral distribution of Caribbean plants (Graham 1976).

Control of "peninsular" distribution patterns.

In addition to climate as discussed above, the "peninsula effect" is frequently consid-
ered to be of importance in the distribution of Florida's organisms. It is a decline in
species richness from the base to the tip of the peninsula because of increased extinctions

610 Florida Entomologist 72(4) December, 1989

and decreased immigration along the peninsula (Simpson 1964). This alone would
suggest an impoverished fauna and flora in the Keys. Means and Simberloff (1987) have
examined herpetofaunal distributions in Florida and find that there is no peninsula
effect as such, but that faunal richness is related to habitat richness. The southwardly
decline of the herpetofauna is related to the progressive decline of (1) rivers and
streams, (2) acid wetlands, (3) mesic hardwood forests, (4) pinelands, and (5) winter
rains for breeding or larval overwintering. The southward decline of terrestrial habitats
in general is a result of low elevation and more extensive wetlands, over extensive
areas: the "everglades effect" (Means & Simberloff 1987). Counter to these trends is
the progressive increase to the south of the native tropical hardwood forests. All these
(and probably other factors) will control the distributions of Florida insects (see also
Blanton & Wirth 1979).


Some generalized conclusions can be suggested about the insect fauna of south
Florida. Future studies will test these predictions.
1. The fauna is comparatively rich for the small land area of subtropical south
2. A smaller component of the insect fauna has come from the north, from elsewhere
in the United States. A larger component has arrived by over-water dispersal from
tropical America. The exact proportion will vary cording to the vagility of the taxon.
3. Comparatively few species will be endemic to the subtropical parts of south
Florida. This is because the area is geologically young, and has been more open to
invasion of species from elsewhere than to the isolation and origin of local species.
4. More species will be found in the subtropical mainland of south Florida than in
the Keys, because of its greater area, more favorable (wetter) climate, and greater
habitat diversity (especially of soils and aquatic or sub-aquatic environments.
5. Most insect species of south Florida are comparatively vagile and will occur else-
where in the circum-Caribbean lowlands or in the lowlands of the islands of the West
Indies. For instance, a large number of Caribbean species of butterflies have entered
south Florida, but few have gone the other way (Brown 1978). In lygaeid bugs 24
species have come into Florida from the West Indies, but only 9 species have gone from
Florida to the West Indies (Slater 1988).
6. Because the insect fauna is vagile, it will be eurytopic, and its trophic associations
will be more general. Fewer species-specific host plant or other feeding associations
will occur. Slater (1988) has noted that 27% of West Indian species of lygaeid bugs also
occur in Florida and generally throughout the southern U.S. and into Central America.
These, however, tend to be "oligophagous" but on "weed" species.


We thank the following for permits to study the insect faunas in the areas under
their protection: Pete Dingier and Rob Line, Metro-Dade County Park and Recreation
Department; J. A. Stevenson, Florida Department of Natural Resources, Division of
Recreation and Parks; John M. Morehead (Superintendent), Gary Hendrix (Director of
Research), and Pat Tolle (Management Technician), Everglades National Park; Donald
J. Kosin, Jack Watson, and Deborah Holle, (Managers) National Key Deer and
Crocodile Lake Wildlife Refuges. William and Ellen Peck generously provided long-
term logistical support on Big Pine Key. Field work was partly supported by operating
grants from the Natural Sciences and Engineering Research Council of Canada. The
manuscript was improved by comments from Howard Frank, M. C. Thomas, W. W.
Wirth, and anonymous reviewers.

Peck: Introduction-Insects of the Florida Keys


BLANTON, F. S., AND W. W. WIRTH. 1979. The Sand Flies (Culicoides) of Florida
(Diptera: Ceratopogonidae). Arthropods of Florida and neighboring land areas.
vol. 10. Florida Department of Agriculture and Consumer Services, Division of
Plant Industry, Gainesville.
BROWN, F. M. 1978. Origins of the West Indian butterfly fauna, pp. 5-30, in Zoogeog-
raphy of the Caribbean. The 1975 Leidy Medal Symposium. Acad. Nat. Sci.
Philadelphia Spec. Publ. 13.
CAMPBELL, D. G. 1978. The Ephemermal Islands; A natural history of the Bahamas.
Macmillan Education Ltd., London. 151 pp.
DARLINGTON, P. J., JR. 1938. The origin of the fauna of the greater Antilles, with
discussion of dispersal of animals over water and through the air. Quart. Rev.
Biol. 13: 274-299.
DEYRUP, M. A., N. CARLIN, J. TRAGER, AND G. UMPHREY. 1988. A review of the
ants of the Florida Keys. Florida Entomol. 71: 163-176.
DONNELLY, T. W. 1988. Geologic constraints on Caribbean biogeography, pp. 15-37
in Liebherr, J. K. (ed.), Zoogeography of Caribbean Insects. Cornell Univ.
Press, Ithaca, N.Y.
ERWIN, T. L. 1983. Tropical forest canopies: the last biotic frontier. Bull. Entomol.
Soc. America 29(1): 14-19.
FRANZ, R., (ed.). 1982. Invertebrates, Rare and endangered biota of Florida (P. C.
H. Prichard ser. ed.). University Presses of Florida, Gainesville, vol. 6, pp. 131.
GAGNE, W. 1979. Canopy-associated arthropods in Acacia koa and Metrosideros tree
communities along an altitudinal transect on Hawaii Island. Pacific Insects 21:
GRAHAM, A. 1976. Late Cenozoic evolution of tropical lowland vegetation in Veracruz,
Mexico. Evolution 29: 723-735.
GRAHAM, A., AND D. M. JARZEN. 1969. Studies in Neotropical paleobotany. I. The
Oligocene communities of Puerto Rico. Ann. Missouri Bot. Gard. 56: 308-357.
HOFFMEISTER, J. E. 1974. Land from the sea; the geologic story of south Florida.
Univ. Miami Press, Coral Gables, Fla.
HOFFMEISTER, J. E., AND H. G. MULTER. 1968. Geology and origin of the Florida
Keys. Geol. Soc. America Bull. 79: 1487-1502.
HOLMES, C. W. 1985. Accretion of the south Florida platform, late Quaternary devel-
opment. American Assoc. Petrol. Geol. Bull. 69: 149-160.
LAWTON, J. H., AND D. SCHRODER. 1977. Effects of plant type, size of geographical
range and taxonomic isolation on number of insect species associated with British
plants. Nature 265: 137-140.
LIEBHERR, J. K. (ed.). 1988. Zoogeography of Caribbean Insects. Cornell Univ.
Press, Ithaca, N.Y.
LONG, R. W., AND 0. LAKELA. 1971. A flora of tropical Florida; a manual of the seed
plants and ferns of southern peninsular Florida. Univ. Miami Press, Coral Ga-
bles, Fla.
MACARTHUR, R. H., AND E. 0. WILSON. 1967. The theory of island biogeography.
Monographs on Population Biology I, Princeton University Press, Princeton.
MEANS, D. B., AND D. SIMBERLOFF. 1987. The peninsula effect: habitat-correlated
species decline in Florida's herpetofauna. J. Biogeog. 14: 551-568.
PECK, S. B., AND DAVIES, A. E. 1980. Collecting small beetles with large-area
"window" traps. Coleop. Bull. 34: 237-239.
PECK, S. B., AND H. F. HOWDEN. 1985. Biogeography of scavenging scarab beetles
in the Florida Keys; post-Pleistocene land-bridge islands. Canadian J. Zool. 63:
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Department of Biology, Carleton University
Ottawa, Ontario K1S 5B6 Canada


A survey of cockroaches, mantids, and walkingsticks in native forests in south Florida
found 15 species, from a total of about 40 (15 of which are introduced) which occur in
all of Florida. Three cockroach species are added to the Florida fauna. Compsodes
schwarzi (Caudell), previously known from Mexico and Texas, is reported from Florida
for the first time. Neoblatella detersa (Walker) and Symploce morse (Hebard), both
known from elsewhere in the West Indies, are reported for the United States for the
first time. The only introduced species found to have invaded native habitats is the


December, 1989

Peck & Beninger: Insects of the Florida Keys

parthenogenetic cockroach Pycnoscelus surinamensis (Linnaeus). Parcoblatta fulves-
cens (Saussure & Zehnter) has invaded from the southeastern United States. The other
13 species are Neotropical (Caribbean or Mexican) in origin.


Se hizo una encuesta de cucarachas, come-piojas, e insects palos en bosques nativos
del sur de la Florida, encontrandose 15 species de un total de cerca de 40 (15 de las
cuales son introducidas) que ocurren en toda la Florida. Se afaden tres species de
cucarachas a la fauna de la Florida. Se report por primera vez a Compsodes schwarzi
(Caudell) de la Florida, previamente conocida de Mexico y Texas. Se report por prim-
era vez de los Estados Unidos a Neoblatella detersa (Walker) y a Symploce moresei
(Hebard), ambas conocidas de las Indias Occidentales. La dnica especie introducida que
se ha encontrado invadiendo habitaciones naturales es la cucaracha partenogendtica
Pycnoscelus surinamensis (Linnaeus). Parcoblattaa fulvescens (Saussure & Zehnter)
ha invadido desde el sudeste de los Estados Unidos. Las otras 13 species son Neot-
ropicales (del Caribe o Mejicanas) de origen.

A survey of some of the insect fauna was made in south Florida, mostly between
1984 and 1986, in about 30 sites, mostly in the Florida Keys (see Peck 1989 for details).
Most collections were made with continuously collecting "large area window traps" or
"flight intercept traps" (see Peck & Davies 1980) in closed canopy West Indian hardwood
hammock forests. The purpose was to contribute to understanding the species composi-
tion of these poorly known habitats. This paper reports on the cockroaches, mantids,
and walkingsticks found to walk or fly into the traps used in the survey. Voucher
specimens are in the collections of the first author; the Florida State Collection of
Arthropods, Gainesville; The National Museum of Natural Sciences, Ottawa, Canada;
and in the Lyman Entomological Museum of Macdonald College, McGill University, Ste
Anne de Bellevue, Quebec, Canada HOA 1C0. Detailed specimen data are available from
the first author. Most determinations can be easily made with the keys in Helfer (1972).
The only previous survey of these insects from south Florida is that of Rehn & Hebard
1912, 1914a).


The Cockroaches (Blattodea)

Sixty-five species of cockroaches are known from the continental United States (Pratt
1988). Keys to most of the genera are in Rehn (1950). Distributional data and references
are given by Princis (1962-1971). Twenty-eight of these species are known from Florida,
and another 5 species may occur there. Of these, about 15 species were probably intro-
duced by man. Of the native species, 11 are known or may be expected in south Florida
(Hebard 1917, Helfer 1972, Rehn & Hebard 1912, 1914a). Eleven species were found in
this study. The (probably) native species Latiblatella rehni Hebard, Phoetalia (=
Leurolestes) pallida (Brunner) and Hemiblabera tenebricosa Rehn & Hebard were ex-
pected but not found. Three species were found to be new records for Florida.

Family Blaberidae

Pycnoscelus surinamensis (Linnaeus), The Surinam cockroach.

Seventy-two specimens were taken throughout south Florida in the Deering Estate,


614 Florida Entomologist 72(4) December, 1989

Old Cutler Hammock, Long Pine Key (open pinelands), Grossman Hammock, south Key
Largo, Fat Deer Key, Key Vaca, Ohio Key, Bahia Honda Key, No Name Key, Big Pine
Key (No Name Road, Watsons and Cactus Hmocks), Middle Torch Key, Cudjoe Key,
and Sugarloaf Key (Sec. 25). Adults were present throughout the year but most abundant
from August to December. The species is circumtropical and was probably spread by
man from Asia. It is established in natural habitats in the U.S. from Florida to Texas.
The species is parthenogenetic, thelytokous and ovoviviparous (Roth 1967). Florida
probably was occupied by multiple invasions from Central or South America (Parker et
al. 1977).

Family Blattidae

Eurycotis floridana (Walker), The stinking cockroach.

Twelve specimens were taken on Long Pine Key (open pinelands), Big Pine Key
(Watsons Hammock) and Big Torch Key. Adults were present only from March to June.
These are flightless cockroaches which must walk into flight intercept traps. The species
is distributed from the Keys to Georgia and Mississippi.

Family Polyphagidae

Compsodes schwarzi (Caudell), Schwarz's cockroach.

One specimen was caught in open pineland forest in Long Pine Key, Everglades
National Park, 28.VIII-5.IX.1986 (identification confirmed by L. Roth; specimen depo-
sited in FSCA). The species is otherwise known only from northwestern Mexico,
Arizona, and Brownsville, Texas. This is the first record for Florida. A much smaller
species, Compsodes cucullatus (Saussure & Zehntner) has been collected, apparently
only once, at Paradise Key (= Royal Palm Hammock) (Blatchley 1920). It was described
from Guatemala and may have been introduced.

Family Blattellidae

Cariblatta lutea minima Hebard, The least yellow cockroach.

One hundred sixty-eight specimens were found, mostly in hardwood hammock
forests, in south Florida and the Keys in Long Pine Key (open pinelands), Royal Palm
Hammock, Grossman Hammock, south Key Largo, Fat Deer Key, Key Vaca, No Name
Key, Big Pine Key (Cactus and Watson's Hammocks), Big Torch Key, Cudjoe Key,
Sugarloaf Key, and Stock Island. Adults occur throughout the year but were most
abundant from May to September. This subspecies is restricted to south Florida, the
Keys and Cuba. The subspecies C. lutea lutea (Saussure & Zehntner) ranges from
central Florida to North Carolina, and Louisiana. The subgenital plates of the two seem
to be distinctive and do not intergrade. They may represent two specific taxa (L. Roth,
personal communication).

Chorisoneura texensis Saussure & Zehntner, The small yellow Texas cockroach.

Four specimens were found only on the south Florida mainland in hardwood ham-
mock forests in Royal Palm Hammock (Everglades N.P.) and Grossman Hammock
(Chekika Recreation Area). Three of these were from November to February, and one
was collected between May and August. The species ranges from Texas to North
Carolina and to south Florida.

Peck & Beninger: Insects of the Florida Keys

Euthlastoblatta gemma (Hebard), The shortwing gem cockroach.

Five specimens were found only in hardwood hammock forests of the Keys; on Big
Pine Key (Cactus and Watson's Hammocks), Big Torch Key and Cudjoe Key. Adults
were caught only from August to February. The species ranges from Florida and Geor-
gia to Texas, and the Bahamas. Princis (965) transferred the species from the genus
Aglaopteryx. Another species, E. diaphana (Fabricius), has much the same distribution
(Princis 1962-1971).

Ischnoptera deropeltiformis (Brunner), The dark wood cockroach.

This was the most frequently found cockroach. Two hundred twenty-eight specimens
were taken in south Florida and the Keys, in the Deering Estate, Long Pine Key
(pinelands), Royal Palm Hammock, Grossman Hammock, south Key Largo, Fat Deer
Key, No Name Key, Big Pine Key (Watson's Hammock), Middle Torch Key, Big Torch
Key, Cudjoe Key, and Sugarloaf Key. The species ranges from the Keys north to New
Jersey, and west through Indiana to Kansas and Texas.

Neoblatella detersa (Walker)

Forty-five specimens were found in south Florida and the Keys, in Old Cutler Ham-
mock, the Deering Estate, Long Pine Key (pinelands), Royal Palm Hammock, south
Key Largo, No Name Key, Middle Torch Key, Big Torch Key, Cudjoe Key, and Sugarloaf
Key (identification confirmed by L. Roth; specimens deposited in FSCA). Adults were
present in all seasons of the year. The species was previously known with certainty only
from Jamaica and Haiti (Princis 1959, 1962-1971; Rehn & Hebard 1927: 74). It had been
reported earlier from Homestead, Lakeland, and Everglades, Florida (Rehn & Hebard
1914a: 379, 1914b: 98), but these determinations were later stated to be misidentifications
of Latiblatella rehni Hebard (Hebard 1917:38, Rehn & Hebard 1927:76), which otherwise
occurs in the Bahamas and Cuba. We found no material with the characters ofL. rehni.

Parcoblatta fulvescens (Saussure & Zehnter), The fulvous wood cockroach.

Twenty-four specimens were found in mainland and Keys forests on Long Pine Key
(pinelands), south Key Largo, Middle Torch Key, and Cudjoe Key. Adults were present
throughout the year but most abundant between June and August. The species is known
to range from the Keys to New York and west to Iowa and Texas.

Plectoptera poeyi (Saussure), The Florida beetle cockroach.

Seventy-seven specimens were found only in the Keys, in hardwood hammock forests
on Fat Deer Key, Vaca Key, Big Pine Key (Cactus Hammock and No Name Road),
Middle Torch Key, Cudjoe Key and Sugarloaf Key. Adults were present in similar
numbers in all seasons of the year. This small beetle-like species is known only from
Florida and Cuba.

Symploce morsei (Hebard)

Twenty specimens were found only in the Keys in hardwood hammock forests, on
south Key Largo, No Name Key, Middle Torch Key, and Cudjoe Key (identification
confirmed by L. Roth; specimens deposited in FSCA). Adults were present throughout
the year. The species is otherwise known only from the Bahamas (Roth 1984). These
are the first U.S. records.


616 Florida Entomologist 72(4) December, 1989

Mantids (Mantodea)

Twenty species of mantids are known from the United States, of which 6 occur in
Florida but only four are known from south Florida (Gurney 1951, Helfer 1972, Rehn
& Hebard 1914a). They are only rarely taken in flight intercept traps.

Mantoida maya Saussure & Zehntner, The little Yucatan mantid.

Twenty-seven specimens were found in south Florida and the Keys at the Deering
Estate, Long Pine Key (open pinelands), south Key Largo, Vaca Key, Big Pine Key
(No Name Road, Watson's and Cactus Hammocks), No Name Key, Big Torch Key, and
Middle Torch Key. Adults occurred between June and September. The species occurs
in south Florida and the Yucatan Peninsula of Mexico.

Gonatista grisea (Fabricius, The grizzled mantid.

Only 4 specimens were found, on Royal Palm tree trunks at the Deering Estate, in
August. The species ranges from South Carolina, through Florida, to Cuba.

Thesprontia graminis (Scudder), The grass-like mantid.

Only seven specimens were taken in open pinelands on Long Pine Key in August.
The species ranges from Florida to Mississippi.

Walkingsticks (Phasmatodea)

Twenty-six species of walkingsticks are known from the United States of which up
to 5 may occur in Florida, but only four are known from south Florida (Rehn & Hebard
1914a). Manomera tenuescens (Scudder), M. brachypyga Rehn & Hebard, and Aplopus
mayeri Caudell were expected in the Keys and south Florida but were not found in this

Anisomorpha buprestoides (Stoll), The two-striped walkingstick

Many specimens were found under boards, but few were collected in flight intercept
traps. Records are from Long Pine Key (open pinelands) and in hammock forest in south
Key Largo, Big Pine Key (No Name Road), and Middle Torch Key. Adults were found
from August to January. The species ranges from south Florida to southeastern Georgia.

Biogeographical Considerations

A total of 15 species of cockroaches, mantids, and walkingsticks was found in native
habitats in south Florida. This is out of a total of about 40 species in these groups (15
of which are introduced) which occur in all of Florida. These groups of insects are
predominantly tropical in distribution and diversity. Only one introduced species, Pyc-
noscelus surinamensis was found to have invaded native habitats. Only Parcoblatta
fulvescens has many related species in the United States north of Florida. It may have
colonized from that direction. All the other genera have more species in the West Indies
or in circum-Caribbean and other Neotropical countries. The ancestral colonizations for
these were most probably either across the Caribbean, or along the northern coast of
the Gulf of Mexico. For eight of these this colonization occurred sufficiently in the past
that their contemporary descendant species distributions are now limited to the southern
United States or northern Mexico. The remaining five species (N. detersa, P. poeyi, S.

Peck & Beninger: Insects of the Florida Keys

morse, M. maya, and G. grisea) still have native distributions including the West Indies
or southern Mexico.

We thank the following for permits to study the insect faunas in the areas under
their protection: Pete Dingier and Rob Line, Metro-Dade County Park and Recreation
Department; J. A. Stevenson, Florida Department of Natural Resources, Division of
Recreation and Parks; John M. Morehead (Superintendent), Gary Hendrix (Director of
Research), and Pat Tolle (Management Technician), Everglades National Park; Donald
J. Kosin, Jack Watson, and Deborah Holle (Managers), National Key Deer and Crocodile
Lake Wildlife Refuges. William and Ellen Peck generously provided long-term logistical
support on Big Pine Key. Field work was partly supported by operating grants to the
first author by the Natural Sciences and Engineering Research Council of Canada. Louis
M. Roth generously helped verify and correct our determinations of the cockroaches,
examined the manuscript, and suggested useful literature.

BLATCHLEY, W. S. 1920. Orthoptera of northeastern America. Nature Publ., In-
dianapolis, Indiana. 784 pp.
GURNEY, A. B. 1951. Praying mantids of the United States. Smithsonian Inst. Rep.
1950: 339-362.
HEBARD, M. 1917. The Blattidae of North America north of the Mexican boundary.
Mem. American Ent. Soc. 2: 284 pp.
HELFER, J. R. 1972 (2nd ed.). How to know the grasshoppers, cockroaches, and their
allies. Pictured Key Nature Series, W. C. Brown Co., Dubuque, Iowa. 359 pp.
Genetic diversity in colonizing parthenogenetic cockroaches. Evolution 31: 836-
PECK, S. B. 1989. A survey of insects of the Florida Keys: post-Pleistocene land-bridge
islands. Introduction. Florida Ent. 72: 603-612.
PECK, S. B., AND A. E. DAVIES. 1980. Collecting small beetles from large-area
"window" traps. Coleop. Bull. 34: 237-239.
PRATT, H. D. 1988. Annotated checklist of the cockroaches (Dictyoptera) of North
America. Ann. Ent. Soc. America 81: 882-885.
PRINCIS, K. 1959. Revision der Walkerschen und Kirbyschen Blattarientypen im
British Museum of Natural History, London. III. Opusc. Ent. 24: 125-150.
PRINCIS, K. 1965. Kleine Beitrage zur Kenntnis der Blattarien und ihrer Verbreitung.
VIII. Eos 41: 135-156.
PRINCIS, K. 1962-1971. Orthopterorum Catalogus (M. Beier ed.) Pars 3, 4, 6-8, 11,
13, 14. W. Junk, The Hague, Netherlands.
REHN, J. A. G., AND M. HEBARD. 1912. On the Orthoptera found on the Florida
Keys and in extreme southern Florida. I. Proc. Acad. Nat. Sci. Philadelphia 64:
REHN, J. A. G., AND M. HEBARD. 1914a. On the Orthoptera found on the Florida
Keys and in extreme southern Florida. II. Proc. Acad. Nat. Sci. Philadelphia
66: 373-412.
REHN, J. A. G., AND M. HEBARD. 1914b. Records of Dermaptera and Orthoptera
from west central and southwestern Florida. J. New York Ent. Soc. 22: 96-116.
REHN, J. A. G., AND M. HEBARD. 1927. The Orthoptera of the West Indies. I.
Blattidae. Bull. American Mus. Nat. Hist. 54: 1-320.
REHN, J. W. H. 1950. Key to genera of North American Blattaria, including established
adventives. Ent. News 61: 64-67.
ROTH, L. M. 1967. Sexual isolation in parthogenetic Pycnoscelus surinanensis and
application of the name Pycnoscelus indicus to its bisexual relative (Dicotyptera:
Blatteria: Blaberidae: Pycnoscelinae). Ann. Ent. Soc. America 60: 774-779.
ROTH, L. M. 1984. The genus Symploce Hebard. I. Species of the West Indies (Dic-
tyoptera: Blattariae, Blattellidae). Ent. Scand. 15: 25-63.


Florida Entomologist 72(4)


Ft. Lauderdale Research and Education Center
University of Florida Institute of Food and Agricultural Sciences
3205 College Ave., Ft. Lauderdale, FL 33314

The Terminix International Co. L.P.
2280 U.S. Highway 19 N., Suite 209
Clearwater, FL 34623


Alates, soldiers, workers, and brachypterous nymphs of Amitermes floridensis n.
sp. from St. Petersburg, Florida, U.S.A., are described for the first time. Distribution
records, biological notes, and significance of A. floridensis are reported.


Se described por primera vez los alados, los soldados, los obreros y las ninfas
braquipteras, de Amitermes floridensis n. sp. de St. Petersburg, Florida, U.S.A. Se
report los registros de la distribuci6n, apuntes biol6gicos, y la significancia de A.

During the course of routine termite identifications and a survey of Florida termites,
several collections of a few wings and alates of an undetermined species of Termitidae
from St. Petersburg, Florida, were noted (Scheffrahn et al. 1988). These specimens
were of considerable significance as no member of this large family (ca. 1600 spp.,
Edwards and Mill 1986) had ever been collected in the eastern United States. The
original specimens, however, were in poor condition and the absence of soldiers further
hampered identification.
On July 2, 1988, swarming alates of this termite were captured near a previous
collection site. Immediately, termite control operators in the St. Petersburg area were
asked to collect any dark-winged alates they encountered during the course of their
work. Two subsequent collecting expeditions were also undertaken. These actions
yielded additional alates and, for the first time, foragers. The species is assigned to the
genus Amitermes as established and defined by Silvestri (1901, 1903). We name this
new species Amitermes floridensis n. sp., the etymology of which is derived from its
unexpected and apparently confined geographical distribution in Florida. We herein
provide: 1) a description of Amitermes floridensis n. sp., 2) notes on its distribution
and biology, and 3) a discussion of the significance of this finding.

Amitermes floridensis, new species

SOLDIER (Fig. 1 A-D). Measurements, in mm by ocular micrometer, adapted from
Light (1927, 1930, 1932)


December, 1989

Scheffrahn et al.: New Species of Termite



Fig. 1. A. floridensis n. sp. soldier. Head and pronotum, lateral (A) and dorsal (B)
views; labium (C), ventral view; and mandibles (D), dorsal view. Horizontal bar = 1
mm for A-C; vertical bar = 0.5 mm for D.

Description. Head capsule light yellow with sparsely scattered setae; head length 1.14
to base of mandibles, minimum head width 0.76 at antennal sockets, maximum head
width 0.90 near posterior end; fontanelle barely visible (at 50X) on frons just posterior
to antennal sockets, surrounded by setae up to 0.16 long; frontal gland visible in interior
of head capsule, as wide as distance between lateral mandibular articulations in front,
narrowing toward posterior edge of head capsule.
Antennae light yellow, with 14 segments (= subsegments); second segment about
half as long as first; third and fourth together slightly longer than second; fourth shorter
than third.
Mandibles yellowish brown, 0.70 long from lateral articulation to tip; near-circular
curve from marginal tooth to tip, minimum mandibular curvature 0.08 measured from

620 Florida Entomologist 72(4) December, 1989

inside surface between tip and marginal tooth to an imaginary line extending from
lateral articulation to tip. Single marginal tooth lying near proximal third of each man-
dible and projected perpendicular from inner edge; tooth projected distinctly from inner
edge of mandible, anterior face of tooth cut more roundly from edge than the more
squarely cut posterior face.
Labrum triangular, rounded at tip; dorsal surface with ca. eight long setae projecting
anteriorly; tip ending level with marginal teeth of mandibles.
Clypeus with medial cleft along anterior margin that forms dividing groove in
Gula narrow in middle, widest (0.29) in anterior half; contraction index (min. width
Smax. width) 0.76.
Pronotum 0.56 wide; sharply elevated anteriorly and with long setae scattered along
entire margin.

Measurements in mm (n = 28) Range Mean S.D. Holotype
1. head length to mandibles 1.07-1.22 1.136 0.038 1.15
2. min. head width at antennae 0.72-0.82 0.764 0.023 0.77
3. max. head width 0.83-0.96 0.899 0.035 0.88
4. head index(=3 1) 0.74-0.86 0.791 0.031 0.77
5. head contraction index (= 2 3) 0.80-0.89 0.850 0.020 0.88
6. mandible length 0.67-0.77 0.703 0.021 0.69
7. head-mandible index (= 6 + 1) 0.58-0.67 0.619 0.026 0.60
8. min. mandible curvature 0.07-0.09 0.082 0.006 0.09
9. mand. curvature index (= 8 6) 0.10-0.13 0.116 0.009 0.12
10. gular length 0.58-0.75 0.682 0.038 0.70
11. min. gular width 0.20-0.25 0.223 0.014 0.22
12. max. gular width 0.26-0.31 0.294 0.012 0.26
13. gular cntr. index(= 11 12) 0.67-0.86 0.757 0.054 0.84
14. pronotum width 0.51-0.60 0.564 0.023 0.56

Diagnosis. Mandible dentition can be used to categorize the Nearctic and Neotropical
Amitermes soldiers into two convenient groups: those with marginal teeth directed
perpendicular from the surface of the inner edge of the mandible and having a distinct
anterior face, and those whose teeth are directed posterior and lack a well defined
anterior face (e.g. A. emersoni Light). The former group includes A. floridensis, A.
wheeler (Desneux), A. excellent Silvestri, A. brevicorniger Silvestri, A. amifer Silves-
tri, and A. foreli Wasmann. Of these, A. floridensis most closely resembles A. wheeler
in manibular structure and overall size; however, mandibles are shorter and stouter in
the larger A. wheeler soldiers. Amitermes floridensis is the smallest species of this
group. Alates of A. wheeler are larger than A. floridensis.
ALATE (Figs. 2 E-H and 3 14).
Description. Body length about 4.2 with dorsum generally brownish black; venter yel-
lowish white with partial pigmentation of some sternal plates. Head capsule and pro-
notum darkest, covered densely with setae.
Compound eyes very slightly elliptical; ocelli round from anterolateral aspect, about
two-thirds their diameter from eyes; fontanelle egg-shaped, about length of ocellus.
Postclypeus bilobed, twice as wide as long; labrum pointed at apex.
Wing membrane translucent, smoky black, and punctate, setae mostly on margins
and costal veins, but occurring throughout; 2 anterior-most veins (radius and radial
sector) well pigmented throughout entire length, inner vein of pair darker; median vein
near center of wing branching once and becoming lighter near apex; cubitus with 10
branches and ca. 5 subbranches reaching posterior margin and apex, proximal 4-5

Scheffrahn et al.: New Species of Termite

Fig. 2. A. floridensis n. sp. alate. Head, lateral (E) and dorsal (F) views; labium
(G), ventral view; and thorax with wing scales (H), dorsal view. Bar = 1 mm.

branches thicker and darker than rest; forewing scale slightly shorter than length of
pronotum, hindwing scale two-thirds size of forewing scale.
Antennae with 15 segments, centers of segments dark, becoming lighter near articu-
lations; third segment shortest.
Pronotum about twice as broad as long; anterior margin nearly straight, posterior
margin with small cleft at midline.

Measurements in mm (n = 12)
1. length with wings
2. right forewing length
3. overall length
4. head length to mandibles
5. head width at eyes
6. eye, long diameter
7. postclypeus length
8. postclypeus width





Florida Entomologist 72(4)

Fig. 3. A. floridensis n. sp. right forewing (I), dorsal view; and magnified inset (J)
for enclosed area. Horizontal bar = 3 mm for I; vertical bar = 0.2 mm for J.

9. postclypeal index(= 7 + 8) 0.49-0.56 0.528 0.026 0.55
10. pronotum length 0.38-0.42 0.405 0.013 0.41
11. pronotum width 0.69-0.77 0.739 0.023 0.74

Diagnosis. Amitermes floridensis most closely resembles alates described as A.
beaumonti Banks by Snyder (1924). Although not collected with soldiers, he assigned
these alates based on their sympatry with and their relative size to soldiers of A.
beaumonti originally described from Panama by Banks (1918). Although alates are simi-
lar, A. floridensis soldiers differ from those of the slightly larger A. beaumonti as the
latter's marginal tooth rests on the apical third of the mandible. The tooth of A.
beaumonti is well marked with a posterior face but grades off into the anterior edge of
the mandible (Banks 1918, Light 1932).


Description. Head white, not more than 0.92 wide; thorax white and narrow, pronotum
width 0.49. Viscera and gut contents visible; dark brown matter in gut appears grey
through abdominal wall.

Measurements in mm (n = 14) Range Mean S.D.
1. head length with labium 0.87-1.00 0.938 0.042
2. head width 0.79-0.92 0.860 0.032
3. clypeus length 0.18-0.23 0.201 0.014
4. clypeus width 0.33-0.40 0.361 0.018
5. pronotum length 0.18-0.28 0.224 0.029
6. pronotum width 0.45-0.54 0.489 0.036
7. total length 2.80-3.70 3.264 0.272


December, 1989

Scheffrahn et al.: New Species of Termite


Description. More intensely white than workers, especially abdomen, where gut con-
tents not as visible as in worker; structurally similar to workers, but with extended
abdomen; about 1.5 times as long as workers; wing pads conspicuous.

Measurements in mm (n = 8) Range Mean S.D.
1. head length 0.98-1.03 1.014 0.021
2. head width 0.81-0.84 0.824 0.009
3. pronotum width 0.67-0.78 0.724 0.039
4. overall length 3.60-5.12 4.426 0.51
5. forewing pad lengtha 0.93-1.13 1.006 0.083
an= 7, one specimen was last instar nymph with pad length of 2.10.

Holotype Soldier. Florida: Pinellas Co., St. Petersburg. 11-VII-1988 (Coll. R. H. Schef-
frahn). [Florida State Collection of Arthropods, Fla. Dept. Agric. Cons. Serv., Div.
Plant Ind., Gainesville, FL].
Morphotype Alate. Florida: Pinellas Co., St. Petersburg. 2-VII-1988 (Coll. J. R. Man-
gold). [Florida State Collection of Arthropods].
Paratype Soldiers. [Florida State Collection of Arthropods; National Museum of Natural
History, Washington, D.C.; American Museum of Natural History, New York, N.Y.]
Paratype Alates. [Florida State Collection of Arthropods; National Museum of Natural
History, Washington, D.C.; American Museum of Natural History, New York, N.Y.]
Distribution. The type locality and only known distribution of A. floridensis is in the
city of St. Petersburg, Pinellas Co., Florida. Specimens of A. floridensis have been
collected from ten sites in a ca. 15 km2 area in the central and western sections of the
city bounded to the north by Montrose Blvd, to the south by Third Ave. South, to the
west by 37th St., and to the east by First St.
Biology. Foraging groups of a. floridensis, composed of workers, soldiers, and brachyp-
terous nymphs, have been collected in shaded and sunlit locations in wood debris (Man-
gifera indica L., Albizia lebbeck (L.) Benth., and Pinus elliotii Engelm.) in contact
with the soil or in their subterranean galleries connected to the wood. In one case, an
alate was collected with foragers in tunnels built on the undersurface of flat patio stones
on soil adjacent to a home. In another instance, foragers and an alate wing were taken
from a heavily mined 0.6 m section of header board in the framework of a private
residence (S. Shelton pers. comm.). Several other structural infestations have been
reported but not yet substantiated with voucher specimens. Amitermes wheeler and
A. minimus Light have been reported to attack structural lumber in the southwestern
states (Light 1934a). Foraging routes of A. floridensis are lined with dark brown,
nearly black carton matrix, characteristic of this genus. The carton also forms small
chambers in the larger voids of heavily mined wood.
Soldier proportions of A. floridensis in foraging groups are relatively small as is
characteristic of other Nearctic Amitermes spp. (Scheffrahn, unpubl.). A total of 8
foraging groups excavated nearly intact were counted for a combined total of 1,715
workers (W), 71 soldiers (S, 4.1%), and 8 brachypterous nymphs (N). The 3 largest
groups were composed of the following: 1) 598 W, 34 S, and 2 N; 2) 474 W, 17 S, and
2 N; and 3) 411 W, 3 S, and 1 N.
Reproductive and brood centers of A. floridensis colonies, as with other species of
Amitermes lacking epigeal structures, are not traceable from foraging areas and have
not been found. Colonies do, however, cohabitate foraging territories and compete for
food resources with Reticuliterms spp. (Rhinotermitidae). We found a ca. 12 cm diam.


624 Florida Entomologist 72(4) December, 1989

limb lying on the ground infested by foragers of both Reticulitermes flavipes (Kollar)
and A. floridensis. When the limb was broken open and foragers intermingled from
previously intact and segregated galleries, interspecific combat immediately ensued
demonstrating the potent agonistic tendencies of both A. floridensis soldiers and work-
ers toward their larger competitors.
Dispersal flights of A. floridensis occurred on mid-summer afternoons (ca. 1200-1600
hrs) following a heavy shower or during a lingering light rain after a shower. Of other
Nearctic Amitermes, only A. minimus has flight habits similar to A. floridensis (Nut-
ting 1969). The earliest seasonal alate flight of A. floridensis was recorded on July 2
and the latest August 2, both in 1988. The dark wings and atypical flight season of A.
floridensis alates have entertained the curiosity of termite control operators in St.
Petersburg for over 20 years, but a careful appraisal of the specimens in question was
not pursued until now (P. Amick, pers. comm.).


The genus Amitermes Silvestri consists of nearly 100 species world-wide (Scheffrahn
& Su 1987) and ranks as the largest genus in the subfamily Termitinae. Of all isopteran
genera, only Nasutitermes (Nasutitermitinae) and Odontotermes (Macrotermitinae) are
more diverse. Amitermes floridensis brings to nine the number of Nearctic Amitermes
species, all of which occur in the United States. Seven Neotropical species, now includ-
ing A. (= Synhamitermes Holmgren) brevicorniger Silvestri, (E. Ernst, Swiss Tropical
Institute, pers. comm.), have been described in the genus. Nearctic congeners found
nearest to Florida include A, wheeler, A. minimus, and A. parvulus Light which occur
in the semiarid southwest, eastward to southcentral Texas (Light 1932). Amitermes
beaumonti and A. cryptodon Light, the nearest Neotropical species, have been collected
from the Yucatan Peninsula of Mexico (Light 1934b).
The discovery of A. floridensis brings to 16 the number of described species of
Isoptera in Florida (Scheffrahn et al. 1988. The known termite fauna of Florida, until
now, has consisted exclusively of members of the "lower" families, i.e. Kalotermitidae
and Rhinotermitidae, as defined by Wilson (1976). Although quite a number of the
Termitidae or "higher" termites are found throughout the islands of the Bahamas and
Antilles (Snyder 1956), it is surprising that none of these species occurs in Florida,
especially in its most southern extremity. The absence of Amitermes spp. from the
Antillean fauna suggests that the genus invaded Florida from a mainland Nearctic route
along a Gulf Coast corridor and that A. floridensis may be a relict of a once expanded
Nearctic distribution. The likelihood that A. floridensis is recently introduced seems
remote. Members of the Termitidae do not lend themselves to human-aided establish-
ment outside their native distribution. This is demonstrated by the report that only one
termitid, Nasutitermes walker (Hill), has been regarded, with reservation, as having
become established in a new location (New Zealand) from a remote native (Australian)
habitat (Gay 1967).


We are grateful to the following persons for their help in collecting A. floridensis
n. sp. and assisting the authors during field work in St. Petersburg: Breck, Phil, and
Tony Amick, Amick and Son, Inc.; Bill Barrs, Van Waters & Rogers; Mrs. Bench and
Mr. Hood, homeowners; Billie Chapman, Chapman Pest Control, Inc.; Arthur Dales
and Bruce Sibson, Rentokil, Inc.; John Helm and Sam Frontera, Terminix International;
Steve Hobelmann, Hobelmann Exterminating Service; Steve Shelton, Exterm-A-Tech;
Ellen Thoms, Dow Chemical; and supervisory personnel at United Aluminum Products

Scheffrahn et al.: New Species of Termite

of St. Petersburg. We also thank Robin Giblin-Davis, Peter Luykx, Alan Meerow,
Michael Rust, James Tsai, and F. W. Howard (who translated the abstract into Spanish)
for their review of this paper, no. 9571 of the Florida Agric. Expt. Stn. Journal Series.


BANKS, N. 1918. The termites of Panama and British Guiana. Bull. American Mus.
Nat. Hist. 38: 659-667.
EDWARDS, R., AND A. E. MILL. 1986. Termites in buildings, their biology and con-
trol. Rentokil Ltd. East Grinstead, U.K. 261 pp.
GAY, F. J. 1967. A world review of introduced species of termites. CSIRO Bull. no.
286, Melbourne, Australia. 88 pp.
LIGHT, S. F. 1927. A new and more exact method of expressing important specific
characters of termites. Univ. California Publ. Entomol. 4: 75-88.
LIGHT, S. F. 1930. The California species of the Genus Amitermes Silvestri (Isoptera).
Univ. California Publ. Entomol. 5: 173-214.
LIGHT, S. F. 1932. Contribution toward a revision of the American species of
Amitermes Silvestri. Univ. California Publ. Entomol. 5: 355-410.
LIGHT, S. F. 1934a. Habitat and habit types of termites and their economic signifi-
cance, pp. 136-149 in Kofoid, C. A. (ed.), Termites and termite control. Univer-
sity of California Press, Berkeley, Calif. 795 pp.
LIGHT, S. F. 1934b. The termite fauna of Mexico and its economic significance. ibid.
pp. 334-339.
NUTTING, W. L. 1969. Distribution and flights of rare North American desert ter-
mites of the genus Amitermes (Isoptera: Termitidae). Pan-Pacific Entomol. 45:
SCHEFFRAHN, R. H., AND N.-Y. Su. 1987. A world list of species in the genus
Amitermes (Isoptera: Termitidae). Sociobiology 13: 183-190.
SCHEFFRAHN, R. H., J. R. MANGOLD, AND N.-Y. Su. 1988. A survey of structure-
infesting termites of peninsular Florida. Florida Entomol. 71: 615-630.
SILVESTRI, F. 1901. Nota preliminary sui termitidi sud-americani. Boll. Mus. Zool.
Anat. Comp., Torino 16: 1-8.
SILVESTRI, F. 1903. Contribuzione alla conscenza dei termitidi e termitofili. Redia,
Firenza 1: 1-234.
SNYDER, T. E. 1924. Descriptions of new species and hitherto unknown castes of
termites from America and Hawaii. Proc. United States Nat. Mus. no. 2496, 64:
SNYDER, T. E. 1956. Termites of the West Indies, the Bahamas, and Bermuda. J.
Agric. Univ. Puerto Rico 40: 189-202.
WILSON, E. 0. 1976. The insect societies. Harvard Univ. Press, Cambridge, Mas-
sachusetts 548 pp.


Florida Entomologist 72(4)


'Department of Zoology, Southern Illinois University, Carbondale, Illinois, 62901
2University of Colorado Museum, 3115 S. York St., Englewood, Colorado 80110


In his 1972 revision of Telmatotrephes StAl, Lansbury discussed four character states
he considered important in understanding the systematic position of the genus in the
family. We examine the distribution of those characters across the Nepidae and find
two of Lansbury's conclusions to be invalid. Short respiratory siphons are found in
seven nepid genera, including Telmatotrephes, and not two as supposed by Lansbury.
Paired sulci on the prothoracic venter are not unique to Telmatotrephes but are also
found in Nepa Linnaeus. Vestigial, coriaceous metathoracic wings and clubbed egg
respiratory horns without a plastron meshwork remain as valid diagnostic character
states for Telmatotrephes as hypothesized by Lansbury.


En la revision de Telmatotrephes Stal en 1972, Lansbury expuso cuatro caracteres
que l1 consideraba importantes para entender la posici6n sistematica del g6nero en la
familiar. Nosotros examinamos la distribuci6n de esos caracteres en los N6pidos y encon-
tramos que dos de las conclusions de Lansbury son invilidas. Siete generos de nepid
tienen sifones respiratorios cortos, incluendo a Telmatotrephes, y no los dos supuestos
por Lansbury. Parejas de sulci en el venter protoracico no son exclusivos de Telmatot-
rephes, pues tambi6n se encuentran en Nepa Linnaeus. Vestigios de alas coriadeas
metatoracicas y cuernos de huevos respiratorios en maza sin malla de plastr6n, se
mantiene como un caracter diagn6stico vAlido para Telmatotrephes como Lansbury

During our studies of nepid genera of the world, anticipating a cladistic analysis, we
reviewed Lansbury's (1972) revision of Telmatotrephes Stil wherein he compared this
genus to other genera within the family. Because our data and conclusions differ some-
what from his, and because some of the nepid genera we studied are rare in collections,
hence known only to a few workers, we present some notes that should be of interest
to those involved with the taxonomy and phylogeny of Nepomorpha.
Lansbury concluded his revision of the genus Telmatotrephes with a discussion of
four character states he believed to be important in understanding the systematic pos-
ition of Telmatotrephes in the Nepidae (p. 285):

1. Short caudal respiratory siphons.
2. Prominent spiracular apertures on the venter of the prothorax.
3. Coriaceous, vestigial metathoracic wings.
4. Incomplete plastron meshwork on respiratory horns of eggs.

According to Lansbury, short respiratory siphons were found in only one nepid species
outside of Telmatotrephes, i.e., Borborophyes erutus Montandon (subsequently placed
in its own genus, Montonepa, by Lansbury in 1973). The other three character states
Lansbury regarded as unique to Telmatotrephes.


December, 1989

Keffer et al.: Character States in Telmatotrephes

During a recent visit to the National Museum of Natural History (NMNH), one of
us (SLK) observed that four monotypic Ethiopian genera represented in the Raymond
Poisson Collection: Borborophilus Stil, Paranepa Montandon, Nepita Poisson, and
Nepella Poisson, also had short siphons. Poisson's 1965 catalogue of Ethiopian Nepidae
confirmed those observations and listed precise siphon measurements (Poisson 1965,
pp. 230-231) which are summarized in Table 1. In addition to the Ethiopian genera and
the Oriental M. erutus, we also observed that the Palearctic N. hoffmanni Esaki posses-
ses a short siphon (also noted by Esaki 1925, p. 314). Thus, short respiratory siphons
are shared by seven known nepid genera and not two as supposed by Lansbury.
The "spiracular apertures" (Lansbury's terminology) of Telmatotrephes are paired
sulci lateral to the median prosternal ridge and posteromedial to the coxal cavities
(Lansbury 1972, Figs. 2, 16, 34, 41, 56). They are deep, glabrous, and distinct from the
surrounding propleura and sternum. Two aperture shapes are evident in Telmato-
trephes (Lansbury 1972, p. 271): elongate in the Neotropical species and triangular in
the Oriental species. A survey of the synoptic collections of Nepidae in the NMNH and
the Polhemus Collection revealed that paired sulci on the venter of the prothorax are
also found in Nepa Linnaeus but absent in all other nepid genera. The sulci ofN. cinerea
Linnaeus (Fig. 1), N. sardiniensis Hungerford (similar to N. cinerea), and N. apiculata
Uhler (Fig. 3) are narrowly triangular and thus somewhat intermediate in shape be-
tween the Oriental and Neotropical Telmatotrephes. N. hoffmanni has broadly triangu-
lar sulci (Fig. 2) which closely resemble those of the Oriental Telmatotrephes. In short,
ventral paired prothoracic sulci are not unique to Telmatotrephes but are instead found
in both Telmatotrephes and Nepa.
It should be noted that these sulci have nothing to do with spiracular openings as
assumed by Lansbury (1972). Dissection of specimens of N. apiculata reveals that
internally each sulcus ends anteriorly in an apodeme and not in a spiracular opening
(Fig. 4). As noted by Hamilton (1931, p. 1091 and Plate I) in his description of adult N.
cinerea, and McPherson & Packauskas (1987, p. 683) in their description of nymphal N.
apiculata, the most anterior pair of spiracles is found ventrally in the membrane be-
tween the pro- and mesothorax and not in the area of the sulci. The tracheal system of


Body Siphon Body/
Taxon length length Siphon

Nepa hoffmanni (Esaki)1,' 21.5-23 mm 3 mm >7
Borborophilus afzelii (StAl)2. 15-17 3-4.5 >3.77
Paranepa primitive (Montandon)2,5 15-17.5 3.5-4 >4
Nepita djaloni Poisson2,5 13-14 2.75-3 >4
Nepella pauliani Poisson2,5 18.5 2 9.25
Montonepa erutus (Montandon)3,5 14.25 0.9 15.83
Telmatotrephes sculpticollis StAl4 31-32 6 >5
T. ecuadorensis Lansbury4 22.8 unknown ?
T. grandicollis Kuitert4,5 25-27 4.5-5.5 >4.9
T. chinensis Lansbury4 25.5 4.5 5.67
T. breddini Montandon4'5 30 8 3.75
T. carvalhoi De Carlo4 25 2 12.5

'Esaki 1925, p. 314
2Poisson 1965, pp. 230-231
3Lansbury 1973, p. 111
'Lansbury 1974, pp. 273, 277, 279, 280, 282, 283
6Personal observation


Florida Entomologist 72(4)

1 2

ap su ap cr

3 4

Figs. 1-3. Venter of prothorax: 1. Nepa cinerea. 2. Nepa hoffmanni. 3. N. apiculata.
Fig. 4. Internal midlongitudinal view of sulcus of N. apiculata.
Abbreviations: ap, apodeme; cc, coxal cavities; cr, coxal rim; su, sulcus.

Nepa was studied earlier and figured in detail by Brucher (1916) and Poisson (1924),
who found the same arrangement of spiracles.
All specimens of Telmatotrephes examined by Lansbury had leathery, vestigial
metathoracic wings. Reduced, membranous metathoracic wings seem to occur fre-
quently in the Nepini, e.g., Montonepa erutus and Borborphyes mayri StAl (Lansbury
1973, pp. 111 and 113), Nepa dollfusi Esaki (Esaki 1928, p. 437), N. hoffmanni, and
Laccotrephes pseudoampliatus Poisson (both personal observation). However, truly
vestigial, leathery metathoracic wings appear to be unique to Telmatotrephes.
Eggs of two of the six currently recognized species of Telmatotrephes have been
examined. Hinton (1961, pp. 240-241) studied the eggs of T. breddini Montandon. Eggs
of T. grandicollis Kuitert were described by Lansbury (1972, p. 273) and found to be
indistinguishable from those of T. breddini. In both instances the respiratory horns of
the eggs were clubbed and lacked a plastron meshwork on the inner margin. Nowhere
else in the Nepidae thus far studied are these two egg character states found (i.e.,
Paranepa, Nepa, Laccotrephes StAl, Cercotmetus Amyot and Serville, and Ranatra
Fabricius, Hinton 1961, 1962; Goondnomdanepa Lansbury, 1974; Curicta Stil, personal
observation); those of Austronepa Menke and Stange, Borborophilus, Borborophyes
Stal, Montonepa, Nepella, and Nepita remain unknown. Thus, they so far appear to be
truly diagnostic for the genus Telmatotrephes.
In conclusion, we have invalidated two of the four conclusions reached by Lansbury
about character distribution in Telmatotrephes and other nepine genera. Short respirat-
ory siphons are found in seven genera, including Telmatotrephes, and not two as sup-
posed by Lansbury. Paired sulci on the prothoracic venter are not unique to Telmatot-
rephes but are also found in Nepa. Vestigial, coriaceous metathoracic wings and clubbed


December, 1989

Keffer et al.: Character States in Telmatotrephes

egg respiratory horns without a plastron meshwork remain as valid diagnostic charac-
ters for Telmatotrephes.


We would like to thank Dr. Richard Froeschner of the NMNH who generously
provided the senior author access to the Poisson Collection of Ethiopian Nepidae. Speci-
mens studied at the NMNH included, Borborophilus afzelii Stal, Paranepa primitive
Montandon, Nepita djaloni Poisson, Nepella pauliani Poisson, Montonepa erutus (type
collection), Laccotrephes pseudoampliatus, and many other species of African Lacco-
trephes. Specimens of N. apiculata examined are in the Southern Illinois University
Entomological Collection, those of Nepa cinerea, N. hoffmanni, Telmatotrephes grand-
icollis Kuitert, T. breddini Montandon, Borborophyes mayri StAl, and Nepella pauliani
are in the Polhemus Collection (University of Colorado Museum at Englewood).


BRUCHER, F. 1916. La Nepe Cendree. Arch. Zool. Exp. Gen. 55(1): 483-514, 20 text
ESAKI, T. 1925. Einige Wasser-Hemipteren aus Tsingtau. Entomol. Mitteilungen 14:
- 1928. Contribution to the knowledge of the genus Nepa (Hemiptera: Nepidae).
Ann. Mag. Nat. Hist. 10: 434-441, pl. 15.
HAMILTON, M. A. 1931. The morphology of the waterscorpion Nepa cinerea Linnaeus.
Proc. Zool. Soc. London 3: 1067-1136, 6 plates, 22 figs.
HINTON, H. E. 1961. The structure and function of the egg-shell in the Nepidae
(Hemiptera). J. Insect Physiol. 7: 224-257.
1962. A key to the eggs of the Nepidae (Hemiptera). Proc. R. Entomol. Soc.
London (A) 37: 65-68.
LANSBURY, I. 1972. A revision of the genus Telmatotrephes StAl (Hemiptera-
Heteroptera, Nepidae). Zool. Scripta 1: 271-286.
1973. Montonepa gen. n. from India with notes on the genus Borborophyes
StAl (Hemiptera-Heteroptera, Nepidae). Zool. Scripta 2: 111-118.
1974. A new genus of Nepidae from Australia with a revised classification of
the family (Hemiptera: Heteroptera). J. Australian Entomol. Soc. 13: 219-227.
MCPHERSON, J. E., AND R. J. PACKAUSKAS. 1987. Life history and laboratory
rearing of Nepa apiculata (Heteroptera: Nepidae), with descriptions of immature
stages. Ann. Entomol. Soc. Am. 80: 680-685.
POISSON, R. 1924. Contribution a l'6tude des Hlmipteres aquatiques. Bull. Biol. Fr.
Belg. 58: 49-305, 35 figs., pls 1-13.
1965. Catalogue des HeteroptBres Hydrocorises africanomalgaches de la
famille des Nepidae (Latreille) 1802. Bull. Inst. Fr. Afr. Noire (A) 27: 229-259.

630 Florida Entomologist 72(4) December, 1989


Florida State Collection of Arthropods
P. O. Box 1269, Gainesville, Florida 32602

Department of Entomological Sciences
University of California, Berkeley, California 94720


Stenotabanus woodruffi n. sp. is described and figured from a single female em-
bedded in amber from the Dominican Republic. This species is compared with similar
species of Tabanidae, living and fossil, known from the Greater Antilles.


Stenotabanus woodruffi n. sp. se describe e ilustra a partir de una hembra incrustada
en ambar de la Repiblica Dominicana. Ademas, esta especie es comparada con otros
tabanidos similares conocidos, vivientes y f6siles, en las Antillas Mayores.

In 1986, Dr. Robert E. Woodruff received on loan a small piece of amber from J.
Brodzinsky, which he showed to the senior author. The coincidence of discovering that
another horse fly in amber from the same source existed and was being described by
Lane and Poinar caused us to compare notes and exchange information with mutual
benefit. There seems to be no need to repeat here the introductory and literature
review provided in the preceding description of Stenotabanus brodzinskyi Lane, Poinar
and Fairchild (1988).

Setnotabanus woodruffi sp. nov.

A small yellowish brown species with apically fumose wings, a nearly parallel-sided
frons, bicolored third antennal segments, and a patterned mesonotal integument.
Female. Length of right wing 8.2 mm, left wing incomplete apically. Body length
about 9.0 mm. Venation normal, all marginal cells open except anal closed, no appendix
at fork of 3rd vein, stigma brownish. Apical third of wing somewhat infuscated, darker
anterior to 3rd vein and veins broadly but diffusely brown margined. Basicosta sharply
pointed, without macrosetae like those on adjoining costa. Costa, subcosta, and R beset
with strong, short, dark setae. Halteres with slender pale stem and oval, dark brownish
knob. Legs slender, the tibiae not flattened nor inflated. Tibiae with a definite but short
fringe of nearly erect hairs. Hind tibiae without terminal spurs, but with sparse longer
dark hairs interspersed among a fringe of short pale hairs. Mid tibiae with 2 strong
terminal spurs. Fore tibiae without spurs. Tarsal claws simple, paired on all legs where
the tarsi are preserved.
Head with eyes and frontal area somewhat obscured by overlying cracks, but frons
narrow, index about 8.3, narrower below with a divergence index of about 2.0, (indices
derived from the accompanying camera lucida drawings, Fig. 1, 2). Frontal callus cla-

Fairchild & Lane: Fossil Stenotabanus 631


Fig. 1. Stenotabanus brodzinskyi L., P. and F. holotype. F, frons, antenna and left
palpus. Fig. 2. Stenotabanus woodruffi n. sp. holotype F, frons and right antenna. All
figures to same scale, shown at right of Fig. 1.

vate, apparently attached above to a slender ridge-like median callus. Vertex with a
tubercle, bearing vestiges of at least 2 ocelli; upper third of frons and vertex densely
beset with long black hairs. Post-orbital hairs sparse, pale, and difficult to see. Eyes
bare, no pattern evident. Palpi and probosccis partially obscured, apparently subequal
in length, the second palpal segment slender though not thread-like. Antennae with
basal plate of third segment pale brownish, with a sharp dorsal angle, and considerably
longer than contrasting black 4-annulate terminal portion; scape and pedicel concolorous
with basal plate, but covered with relatively long dark hairs. Surface color pattern of
thorax and abdomen, if any, not preserved. Abdomen yellowish brown, darker termi-
nally, without clear integumental pattern. Thoracic integument light brown, with a
broad central dark stripe and a pair of dorsolateral dark stripes separated from median
dark area by narrow pale stripes. Scutellum concolorous with mesonotum anteriorly,
but posterior portion darker. Legs light yellowish brown, all tarsi, distal half of fore
tibiae and tip of fore femora notable darker brown.
Holotype female No. 10543, Domincan Republic, J. Brodzinsky collector. To be de-
posited in U. S. National Museum of Natural History.


The visible characters of this specimen place it in the subfamily Tabaninae and the
tribe Diachlorini, where it appears quite similar to some elements of the catch-all genus
Stenotabanus. Some of the important head characters, such as the condition of the
frontal calli, palpi, and proboscis are not well displayed, but possibly some further
cutting of the amber might reveal these structures more clearly. Its small size and
general appearance seem much like some modern species from the Greater Antilles, but
the combination of visible character states is not precisely like any living species with
which we are familiar. The wing pattern resembles that of Stenotabanus mellifluous J.
Bequaert from Cuba, but that species is much larger and has more slender unicolorous
antennae and no vestiges of ocelli. The specimen has been compared carefully by both
of us with the holotype of Stenotabanus brodzinskyi. It differs from that species by
being much paler in color of integument, with only parts of mesonotum, tarsi, and

Florida Entomologist 72(4)

annulate part of antennal flagellum black. The frons is considerably narrower and less
convergent below, the annulate portion of the antennal flagellum is relatively shorter,
the basal plate broader, and the dorsal angle markedly more acute. The smoky wing
apex of woodruffi also separates it from brodzinskyi. These character states can best
be appreciated by reference to the accompanying figures of both species, drawn by the
senior author with the aid of a camera lucida on a Wild binocular microscope, while the
amber pieces were immersed in colorless mineral oil.
We take great pleasure in dedicating this important paleontological find to Dr.
Robert E. Woodruff, who not only recognized the importance of this fossil and enable
us to study it, but declined co-authorship. He also read and made astute suggestions
on the several drafts of this paper.


The discovery of two distinct but obviously similar species of tabanids in amber
believed to be at least 25 million years old is an extraordinary occurrence considering
the rarity of fossil Tabanidae. That these specimens show no character states that would
separate them generically from a group of living sympatric and mainly precinctive
Antillean species suggest that evolution in this group of Diptera has been much slower
than in those groups of animals, such as horses, elephants, and primates, whose differen-
tiation is believed to have occurred during the geologically abrupt changes of the Pleis-


Contribution No. 717, Bureau of Entomology, Division of Plant Industry, Florida
Department of Agriculture and Consumer Services, Gainesville, FL 32602.


LANE, R. S., G. O. POINAR, JR., AND G. B. FAIRCHILD. 1988. A fossil horsefly
(Diptera: Tabanidae) in Dominican Amber. Florida Entomol. 71(4): 593-596.


Insects Affecting Man & Animals Research Laboratory
P.O. Box 14565
Gainesville, FL 32604 U.S.A.


The occurrence of polygyny in hybrid fire ants from Mississippi was initially indi-
cated by the clustering behavior of the workers around queens. Polygyny was demon-
strated by the rate of oviposition of isolated queens, and dissection of samples of queens
for the presence of sperm in the spermatheca. The colonies were identified as S. invictal
S. richteri hybrids by gas chromatograph analyses of venom alkaloids and cuticular


December, 1989

Glancey et al.: Polygyny in Hybrid Fire Ants


La ocurrencia de hormigas de fuego hibridas poligamas de Mississippi fue inicial-
mente indicado por el comportamiento de agregaci6n de los obreros alrededor de las
reinas. Se demostr6 poligamia por la tasa de oviposici6n de reinas aisladas, y por la
disecci6n de muestras de reinas para determinar la presencia de esperma en la esper-
matocica. Se identificaron las colonies como hibridos de S. invicta/S. richteri usando
analisis cromatografico de gas de los alcaloides del veneno e hidrocarburos cuticulares.

The imported fire ants, Solenopsis invicta Buren and S. richteri Forel, are agricul-
tural pests that affect several important crops. In addition, high population densities
and the very aggressive nature of the fire ants pose well documented health hazards to
some humans and animals occupying the same habitat (reviewed by Adams, 1986). The
ants are found in 10 southeastern states and Puerto Rico and infest about 93,120,000
ha (Lofgren 1986).
Within the past 15 years, two important discoveries have been made by researchers
working with the imported fire ants. The first discovery was polygyny (multiple func-
tional queens) in S. invicta populations in Mississippi (Glancey et al. 1973). Since this
initial report, polygyny has been reported from S. invicta colonies in Texas, Louisiana,
Georgia, Florida, Oklahoma, Arkansas, and Alabama (Hung et al. 1974, Fletcher 1983,
Lofgren & Williams 1984, Banks & Wojcik unpublished). Polygyny is known to occur
in other species of Solenopsis in North and South America (Banks et al. 1973, Summerlin
1976, Jouvenaz et al. in press).
The second important discovery was the occurrence of viable hybrids of S. invicta
and S. richteri (Vander Meer et al. 1985, Ross et al. 1987a). The hybridization phenome-
non was first detected through biochemical characters (Vander Meer et al. 1985), with
subsequent recognition of morphological characters (J. C. Trager unpublished). Sub-
sequent studies by Diffie et al. (1988) and Vander Meer and Lofgren (unpublished) have
shown that the hybrid has an extensive range in northeastern Mississippi, northern
Alabama, and northwestern Georgia. The expanse of territory occupied by the hybrid
as well as its reproductive viability (Ross et al. 1987a) have raised concerns about the
possibility of range expansion of hybrid fire ants.
We report here evidence for polygynous hybrids of S. invicta and S. richteri in
Mississippi, a unique situation which could further complicate the control of the im-
ported fire ants in the United States.


While collecting imported fire ants in northern Mississippi for studies requiring
queen-rite colonies, BMG and DPW found what appeared to be multiple queen colonies.
To collect a queen from a mound, a shovel-full of tumulus containing ants from the
mound was scattered on the pavement. Any dealates which evoked a clustering behavior
(a response to queen pheromones) were suspected of being mated (Glancey et al. 1975).
When suspected polygynous colonies were recognized, the dealates were collected and
placed in vials, and a sample of the colony was shoveled into a quart jar or 5 gal buckets.
The buckets were lined with FluonR (Banks et al. 1981) to prevent escape of the ants.
We found what appeared to be polygynous colonies at 3 separate locations. Each colony
contained 2 or more dealated females. At the first location, on the shoulders of the
frontage road, 1/2 mi east of US 82 and Alt US 45 junction, Lowndes Co. (ca. 14 miles
W of Columbus), we collected 19 mounds of which 4 had several dealated females. The
4 mounds were within a 100 ft stretch of road. At the second location, on US 45, 1/2 mi
south of Lauderdale (Lauderdale Co.), we collected 2 colonies, both with several deal-

Florida Entomologist 72(4)

ates. At the third location, 1/4 mi south of location #2, we collected 6 colonies of which
one had several dealates.
To test whether or not these 7 colonies were indeed polygynous, dealates were
collected and subjected to a 5 hr quantitative oviposition bioassay (Fletcher et al. 1980).
After the oviposition bioassay, 11 of the queens from one nest, 7 from another nest,
and 4 from a third nest were dissected and a spermathecal examination made.
The hybrid status of these colonies was verified using the methods of Vander Meer
et al. (1985) and is briefly summarized here. Pooled samples of worker ants (50-100)
from each colony were placed in a vial and soaked in hexane (HPLC grade, Burdick and
Jackson, Muskegon, MI) for ca. 24 hr. After soaking, the solvent was transferred to a
clean vial and saved for chemical analysis. Ethanol (70%) was added to the vial contain-
ing the ants to preserve a taxonomic sample. The hexane solution was analyzed for
species-specific venom alkaloids and hydrocarbons by gas chromatography on a VarianR
3700 gas chromatograph equipped with a flame ionization detector. A 30 m DB-1 fused
silica capillary column was used to separate the components of interest. The tempera-
ture program (Ross et al. 1987a) was 1500 to 2850 C at 5 min. with a final temperature
hold of 3 min.


All of the isolated dealates laid sufficient eggs in the oviposition bioassay to meet
the criteria of Fletcher et al. (1980) for polygyny. All of the dissected queens contained
sperm and were mated. The GC patterns of both the venom alkaloids and hydrocarbons
showed that 26 of 27 collected colonies were hybrid colonies (Figure 1). The one excep-
tion was a polygynous S. invicta colony (from site 2).
This finding of hybrid polygynous imported fire ant colonies is interesting for several
reasons. First, the occurrence of these colonies demonstrates some of the variability in
the hybrid. Of the 26 hybrid colonies collected at these three locations, 20 colonies were
apparently monogynous. Secondly, the finding of hybrid polygynous colonies, coupled
with the widely scattered occurrence of polygyny throughout the range of S. invicta in
North America, suggests that polygyny in S. invicta in North America has not arisen
de novo as postulated by Ross et al. (1987b), but is in fact part of the S. invicta genome
which is being expressed in North America. Polygyny in S. invicta has not been
documented in South America, but we assume it occurs because polygyny has been
observed in other Solenopsis spp. in South America (Jouvenaz et al. in press, Wojcik,
Lofgren, & Jouvenaz unpublished). A generally accepted assumption is that the original
introduction of the imported fire ants into North America occurred with only a few
queens for each species (Tschinkel & Nierenberg 1983) which would limit the original
North American gene pool. The presence of diploid males in monogynous and polygyn-
ous colonies is evidence that inbreeding is taking place in S. invicta (Ross & Fletcher
1985). This inbreeding may be the mechanism by which the polygynous phenotype is
being expressed. One year after our initial discovery, we returned to the original collec-
tion area, collected samples, and found that the hybrid multiple queen colonies were
still present.
The occurrence of polygynous S. invicta and S. invicta/S. richteri hybrid colonies
could pose problems in efforts to control these fire ants. Current research is being
directed toward the formulation or discovery of more species-specific control methods.
These efforts have centered on the use of pheromones and the search for specific patho-
gens from their native homelands in South America. Our recent discoveries raise con-
cern whether a species-specific pathogen of S. invicta will also be effective against the
hybrid. In addition, would a toxic bait formulated with the species-specific pheromones
of S. invicta be effective for control of the hybrid? Control of the polygynous pest ant
Monomorium pharaonis with bait toxicants is difficult and inconsistent (Newton &

December, 1989

Glancey et al.: Polygyny in Hybrid Fire Ants



Fig. 1. Gas chromatogram of a hexane soak of hybrid worker ants. Venom alkaloids
are designated by the chain length and the double bond status of the 6- alkyl or alkenyl
group of the piperidine alkaloids associated with S. richteri and S. invicta (i.e. C13:1 is
2-methyl tridecenyl piperidine). S. richteri associated hydrocarbons are defined by the
components above A, and those associated with S. invicta are defined by the compo-
nents above B. See Vander Meer et al. (1985) and Ross et al. (1987) for detailed compari-
son of the hybrid and parent chemistry.

Coombes 1987). A recent report (Glancey et al. 1987) indicates that control of polygyn-
ous S. invicta populations with AmdroR bait has been less effective than that of
monogynous populations. The rapid changes in this insect's ability to survive through
polygyny and hybridization warrants continuous investigation into its strategies for sur-
vival and efforts for its control.


This article represents the results of research only. Mention of a proprietary product
does not constitute an endorsement or recommendation for its use by the USDA.


ADAMS, C. T. 1986. Agricultural and medical impact of the imported fire ants, p.
48-57, in C. S. Lofgren, R. K. Vander Meer (eds.), Fire ants and leaf-cutting
ants, Biology and Management. Westview Press. Boulder, CO.
D. F. WILLIAMS, D. P. WOJCIK, AND B. M. GLANCEY. 1981. Techniques for
collecting, rearing, and handling imported fire ants. USDA, SEA, AATS-S-21.
BANKS, W. A., J. K. PLUMLEY, AND D. M. HICKS. 1973. Polygyny in a colony of
the fire ant, Solenopsis geminata. Ann. Entomol. Soc. Am. 66: 234-5.


636 Florida Entomologist 72(4) December, 1989

DIFFIE, S., R. K. VANDER MEER, AND M. H. BASS. 1988. Discovery of hybrid fire
ant populations in Georgia and Alabama. J. Entomol. Sci. 23: 187-191.
FLETCHER, D. J. C. 1983. Three newly-discovered polygynous populations of the fire
ant, Solenopsis invicta, and their significance. J. Georgia Entomol. Soc. 18:
FLETCHER, D. J. C., M. S. BLUM, T. V. WHITT, AND N. TEMPLE. 1980. Monogamy
and polygamy in the fire ant. Ann. Entomol. Soc. Am. 73: 658-61.
GLANCEY, B. M., C. H. CRAIG, C. E. STRINGER, AND P. M. BISHOP. 1973. Multiple
fertile queens in colonies of the imported fire ant, Solenopsis invicta. J. Georgia
Entomol. Soc. 8: 237-8.
C. T. ADAMS. 1987. The increasing incidence of the polygynous form of the red
imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), in
Florida. Florida Entomol. 70: 400-2.
extraordinary case of polygyny in the red imported fire ant. Ann. Entomol. Soc.
Am. 68: 922.
HUNG, A. C. F., S. B. VINSON, AND J. W. SUMMERLIN. 1974. Male sterility in the
red imported fire ant, Solenopsis invicta. Ann. Entomol. Soc. Am. 67: 909-912.
JOUVENAZ, D. P., D. P. WOJCIK, AND R. K. VANDER MEER. Polygyny in fire ants,
Solenopsis richteri Forel and Solenopsis quinquecuspis Forel (Hymenoptera:
Formicidae) in Argentina. Psyche in press.
LOFGREN, C. S. 1986. History of imported fire ants in the United States, p. 36-47,
in C. S. Lofgren, R. K. Vander Meer (eds.), Fire ants and leaf-cutting ants:
Biology and Management. Westview Press. Boulder, Co.
LOFGREN, C. S., AND D. F. WILLIAMS. 1984. Polygynous colonies of the red im-
ported fire ant, Solenopsis invicta (Hymenoptera: Formicidae) in Florida.
Florida Entomol. 67: 484-6.
NEWTON, J., AND D. S. COOMBES. 1987. A comparison of a range of novel and
conventional insecticides for Pharaoh's ant control. Intern. Pest Cont. 29: 45-7.
ROSS, K. G., AND D. J. C. FLETCHER. 1985. Genetic origin of male diploidy in the
fire ant, Solenopsis invicta (Hymenoptera: Formicidae), and its evolutionary
significance. Evolution 39: 888-903.
Ross, K. G., R. K. VANDER MEER, D. J. C. FLETCHER, AND E. L. VARGO. 1987a.
Biochemical phenotypic and genetic studies of two introduced fire ants and their
hybrid (Hymenoptera: Formicidae). Evolution 41: 280-93.
Ross, K. G., E. L. VARGO, AND D. J. C. FLETCHER. 1987b. Comparative biochem-
ical genetics of three fire ants species in North America, with special reference
to the two social forms of Solenopsis invicta (Hymenoptera: Formicidae). Evolu-
tion 41: 979-90.
SUMMERLIN, J. W. 1976. Polygyny in a colony of the southern fire ant. Ann. Entomol.
Soc. Am. 69: 54.
TSCHINKEL, W. R., AND N. C. E. NIERENBERG. 1983. Possible importance of re-
latedness in the fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae)
in the United States. Ann. Entomol. Soc. Am. 76: 989-91.
VANDER MEER, R. K., C. S. LOFGREN, AND F. M. ALVAREZ. 1985. Biochemical
evidence for hybridization in fire ants. Florida Entomol. 68: 501-6.

Howard et al.: Eye Color Changes 637


University of Florida
Fort Lauderdale Research and Education Center
3205 College Avenue
Fort Lauderdale, FL 33314

Florida State Collection of Arthropods
Bureau of Entomology, DPI, FDACS
P.O. Box 1269, Gainesville, FL 32602


Changes in eye color in response to light and darkness were observed in
Trigonotylus doddi (Distant) (Heteroptera: Miridae), Saccharosydne saccharivora
Westwood, Perkinsiella saccharicida Kirkaldy (Homoptera: Delphacidae), and Cyarda
melichari Van Duzee (Homoptera: Flatidae). Histological examinations of the eyes of
P. saccharicida revealed that pigments were condensed in a zone proximal to the crys-
talline cones when light-adapted, and dispersed distally into the region of the cones
when dark-adapted. This adaptation is believed to occur primarily in nocturnal insects
or species that are active by day and night. Eye color changes were not observed in 23
additional species of Heteroptera and Homoptera collected in Southern Florida, includ-
ing Unerus colonus (Uhler) (Homoptera: Cicadellidae), which is reported for the first
time from the United States.


Se observaron cambios en el color del ojo como respuesta a la luz o la oscuridad en
Trigonotylus doddi (Distant) (Heter6ptera: Mirida), Saccharosydne saccharivora
Westwood, Perkinsiella saccharicida Kirkaldy (Hom6ptera: Delphacida) y Cyarda
melichari Van Duzee (Hom6ptera: Fldtida). Examines histol6gicos de los ojos de P.
saccharicida revelaron que los pigmentos fueron condensados en una zona pr6xima a
los conos cristalinos cuando adaptados a la luz, y dispersados distalmente en la region
de los conos cuando adaptados a la oscuridad. Se cree que esta adaptacin primariamente
occurred en insects nocturnos o en species los cuales son activos dia y noche. No se
observaron cambios en los colors de los hojos en 23 species adicionales de Heteroptera
y Homoptera colectadas en el sur de Florida, incluyendo Unerus colonus Uhler
(Homoptera: Cicadellidae), la cual especie se registra por primera vez en los Estados

Migration of screening pigments of the compound eye in response to changing light
conditions is known in species of various insect orders, including Heteroptera (Bedau
1911) and Homoptera (Howard 1981), and has been explained as follows (Bernhard &
Ottoson 1960, Walcott 1975): In the superposition eye, in response to light, a photochem-
ical process takes place which induces the pigments to travel in secondary pigment cells
to form a dense band proximal to the crystalline cones, optically isolating each om-
matidium. In darkness, the pigments migrate distally in these cells into the cone area,
so that light entering any one facet may act on the retinula cells of neighboring om-
matidia. By varying the amount of light entering the photoreceptor cells, the screening
pigment migration system is analogous to the pupil mechanism of vertebrates (Hoglund

Florida Entomologist 72(4)

& Struwe 1970, Stravenga & Kuiper 1977). The color of insect eyes is often largely
determined by the screening pigments, thus changes in the position of pigments are
seen externally as changes in the color of the compound eyes.
Our current interest in this mechanism is that although the color of the eyes is
generally not included in taxonomic descriptions of Heteroptera and Homoptera, this
character may be useful in field identifications.
Also, since photomechanical changes in the eyes associated with light and dark
conditions are more pronounced in nocturnal than diurnal insects (Bernhard & Ottoson
1960, Parker 1932), simple observations for eye color changes as described in this paper
can provide clues as to this aspect of an insect's natural history, as was the case with
the American palm cixiid, Myndus crudus Van Duzee (Howard 1981).
Here we report observations of several species of Heteroptera and auchenorrhynch-
ous Homoptera collected near Ft. Lauderdale, Florida to, determine whether their eyes
undergo externally visible color changes in response to light and dark conditions. We
selected one of the species, the sugarcane planthopper, Perkinsiella saccharicida Kir-
kaldy (Homoptera: Delphacidae), for histological study of this mechanism.


Live true bugs, leafhoppers, and planthoppers were separated from sweepnet sam-
ples or collected by hand from foliage during daylight hours at the Ft. Lauderdale
Research and Education Center. They were held in glass vials and the eyes examined
under a dissecting microscope in a well-lit laboratory at ca. 25C. The vials with the
insects were then placed in a dark chamber for periods of several hours. They were
removed briefly to the light ca. every 10-15 min and examined under a microscope for
a change in eye color. Insects which exhibited a change in eye color in response to a
dark period were left in the light for 1/2 to several hours and re-examined to determine
whether the eye color had returned to its light-adapted condition. These tests were
repeated about five times with each insect species.
Pigment migration was studied histologically in the sugarcane planthopper. Twenty
sugarcane planthoppers were collected from sugarcane and divided into two groups of
10 each. One group was placed in the dark chamber and the other exposed to light.
After an hour, at which time there were pronounced differences in eye color between
the two groups, the insects were fixed immediately in Bouin's solution and the compound
eyes removed, dehydrated in a tertiary butanol and toluene series (Sass 1958), embed-
ded in paraplast, then sectioned with a microtome at 12 pim. The sections were mounted
on microscope slides and the paraffin removed with a xylene bath. Examinations were
made with a compound microscope at 100 X. Voucher specimens are in the Florida State
Collection of Arthropods or the authors' collections.


Eye color changes were observed in the following species (names followed by the
eye color in light-darkness, respectively): Heteroptera, Miridae: Triognotylus doddi
(Distant), light gray-maroon (Fig 1, a & b); Homoptera, Delphacidae: West Indian
canefly, Saccharosydne saccharivora Westwood (Delphacidae), yellow-dark purple (in-
termediate stage-orange); sugarcane planthopper, light gray-dark gray; Homoptera,
Flatidae: Cyarda melichari Van Duzee, adult, light gray-maroon, nymph, white-dark
The changes in eye color were not timed precisely, but it was observed that at the
same temperature the change from light to dark adaptation took less than 10 minutes
in T. doddi and more than 30 minutes in the West Indian canefly.


December, 1989

Howard et al.: Eye Color Changes

Fig. l(a). Trigonotylus doddi with light-adapted eyes, and (b) dark-adapted eyes.

Examinations of sections of the compound eyes of the sugarcane planthopper showed
that the externally visible difference in color between the light- and dark-adapted eyes
is related to distal-proximal migration of pigments. When the eye is light-adapted, the
pigments are condensed in a zone proximal to the crystalline cones (Fig. 2a). When dark-
adapted, the pigments are dispersed into the zone of the crystalline cones (Fig. 2b), and
probably because of the greater proximity of pigments to the cuticle, the eye appears
darker externally. This is the same kind of mechanism observed previously in the Amer-
ican palm cixiid (Howard 1981), and is undoubtedly similar in the other Heteroptera
and Homoptera species in which we observed eye color changes in response to light and
We were unable to detect color changes in the eyes of 23 other species of Heteroptera
and Homoptera that we examined. These included: Heteroptera, Alydidae: Stenocoris
sp., Pentatomidae: Mormidea pama Rolston; Homoptera, Cicadellidae: Aceratagallia
sanguinolenta (Provancher), Acinopterus angulatus Lawson, Agallia albidula Uhler,
Balclutha incisa (Matsamura), B. hebe (Kirkaldy), Chlorotettix rugicollis Ball, C.
minimus Baker, Empoasca sp., Graminella villica (Crumb), Homalodisca insolita
(Walker), Hortensia similis (Walker), Oncometopia nigricans (Walker), Polyamia ob-
tecta (Osborn & Ball), Protalebrella brasiliensis (Baker), Stragania robusta (Uhler),
Texananus excultus (Uhler), Unerus colonus (Uhler), Xerophloea viridis (F.) Ful-
goroidea: Acanalonia latifrons (Walker), Cyrpoptus reineckei Van Duzee, and Stobaera
concinna (Stal), all of which were collected in open fields. The 7 specimens of U. colonus
collected July 12, 1983 at the Ft. Lauderdale Research and Education Center by D. M.
Beatty using a sweepnet over mixed vegetation represent the first U.S. record of this
neotropical species.





Fig. 2. Long sections of eyes of Perkinsiella saccharicida. (a) Light-adapted eye: pigment granules within secondary pigment cells are
aggregated into a dense band enclosing ends of cones (b) Dark-adapted eye: pigment granules disperse distally into regions of cones.

Howard et al.: Eye Color Changes 641

The relatively slow migration of distal eye pigments inward in the light and outward
in darkness occurs commonly in moths and other nocturnal insects (Bernhard & Ottoson
1960 Parker 1932). The American palm cixiid (Howard 1981), the West Indian canefly
(Guagliumi 1953, Metcalfe 1968) and the sugarcane planthopper (Perkins 1903) are all
to some degree active both day and night. The bugs and leafhoppers that we observed
that did not undergo eye color changes probably are diurnal species with apposition
eyes. Taxonomists might note that in Heteroptera and Homoptera in which the exter-
nally viewed eye color of the live insects changes in response to light and darkness, the
eye color of the dead, dried specimens is generally that of the dark-adapted eye.


We wish to thank J. V. DeFilippis for photography, D. M. Beatty for collecting
insects, and J. P. Kramer and T. J. Henry of the Insect Identification and Beneficial
Insects Introduction Institute, USDA, for confirming the identification of Unerus col-
onus and Trigonotylus doddi, respectively. We thank Rudolf Scheffrahn (University of
Florida), Lionel Stange (Florida Department of Agriculture and Consumer Services)
and George Steyskal (U.S. Department of Agriculture) for reviewing the manuscript.
Richard M. Baranowski (University of Florida), Lois B. O'Brien (Florida A&M Univer-
sity), Joseph C. Schaffner (Texas A&M University) and the late eminent entomologist,
Reece I. Sailer (University of Florida) reviewed an earlier version of the manuscript.
This paper is published as Florida Agriculture Experiment Station Journal Series No.
9929 and Florida Department of Agriculture and Consumer Services, Division of Plant
Industry, Bureau of Entomology Contribution No. 707.


BEDAU, K. 1911. Das Facettenauge der Wasserwanzen. Z. Zool. 97: 417-456.
BERNARD, C. G., AND D. OTTOSON. 1960. Studies on the relation between the pig-
ment migration and the sensitivity changes during dark adaptation in diurnal and
nocturnal Lepidoptera. J. General Physiol. 44: 205-215.
GUAGLIUMI, P. 1953. El saltahoja de la cafra de azucar, Saccharosydne saccharivora
Westw., y la fumagina en Venezuela. Bol. Tec. Inst. Nat. Agric. Venezuela No.
7. 82 pp.
HOGLUND, G., AND G. STRUWE. 1970. Pigment migration and spectral sensitivity in
the compound eye of moths. Z. Vergl. Physiol. 67: 229-237.
HOWARD, F. W. 1981. Pigment migration in the eye of Myndus crudus (Homoptera:
Cixiidae) and its relationship to day and night activity. Insect Sci. Application
2: 129-133.
METCALFE, J. R. 1968. Studies on the biology of the sugarcane pest Saccharosydne
saccharivora Westw. (Horn: Delphacidae). Bull. Entomol. Res. 59: 393-408.
PARKER, G. H. 1932. The movements of the retinal pigment. Ergebnisse der Biologie
9: 239-291.
PERKINS, R. C. L. 1903. The leafhopper of the sugarcane. Bd. of Commissioners of
Agric. and For., Terr. Hawaii, Div. of Ent. Bull. No. 1, 38 pp.
SASS, J. E. 1958. Botanical Microtechnique. Iowa St. Univ. Press, Ames, Iowa.
STRAVENGA, D. G., AND J. W. KUIPER. 1977. Insect pupil mechanisms. The pigment
migration in the retinula cells of Hymenoptera (Suborder Apocrita). J. Comp.
Physiol. A 113: 55-72.
WALCOTT, B. 1975. Anatomical changes during light adaptation in insect compound
eyes, pp. 20-33 in G. A. Horridge (ed.), The compound eye and vision of insects.
Clarendon Press, Oxford.

Florida Entomologist 72(4)


Department of Biological Sciences
Illinois State University
Normal, Illinois 61761, USA


An apparatus has been developed for monitoring the timing and duration of cricket
calling song, using a simple electronic device coupled to an Apple II microcomputer.
The calling activity of up to three insects can automatically be recorded and stored to
magnetic disc. An analysis program determines the percent of time spent calling for
each half-hour block of a 24-hour recording period. A graphical representation of the
temporal pattern of calling is also an available option. Other microcomputers can be
used with minor modification of the connections, and the ancillary electronics required
for this purpose are inexpensive and readily constructed.


Presentamos un aparato electr6nico para medir dos aspects del canto de grill6s: la
distribui6n temporal y la duraci6n. El aparato es connectado al minicomputador "Apple
II". Este montaje puede grabar hasta tres insects y pone automAticamente en disco
magn6tico los resultados. Un program de andlisis determine el porciento de tiempo en
canto por cada media-hora en un period de 24-horas. Tambien se puede representar
graficamente el patr6n temporal del canto. Se puede adaptar el aparato para usarlo con
otras marcas de minicomputadores usando electr6nicas baratas y fAciles.

Although much is known of the mating behavior of crickets (Orthoptera: Gryllidae),
few studies have been conducted on diel patterns of calling in this diverse insect group
(Walker 1983). Male crickets call to attract sexually receptive females, and the timing
and duration of acoustic signalling activity are crucial to male reproductive success. In
many species, males appear to call throughout most of the night, placing practical
limitations on the use of standard observational sampling methods (Altmann 1974) which
can often be extremely laborious. Consequently, some researchers have employed elec-
tronic sound relay devices to monitor cricket calling (e.g., Cade 1981, Sakaluk et al.
1987, Rost & Honegger 1987). The construction of such instruments, however, can be
prohibitively expensive or beyond the technical expertise of most researchers. Accord-
ingly, we have developed an inexpensive electronic addition to the Apple" II series
microcomputer which simultaneously records the calling of up to three insects and
stores the data directly to disk. An associated analysis program determines the propor-
tion of time spent calling by each male for each half-hour of recording time, and presents
the results in a printed table. A graphics program permits the calling activity of each
male to be plotted as a function of real time.


The requirements are an Apple II+ computer with 48K of memory, a single disk
drive, and a CRT monitor. If a printer is available, the programs can make use of it,


December, 1989

Kidder & Sakaluk: Acoustical Activity Recorder


but this feature is not essential. To record as a function of real time, the computer must
be equipped with a clock. Finally, a simple electronic circuit is required to convert the
electrical impulses from the three microphones into signals appropriate to the inputs
available at the Apple's game port. This and the requisite programming complete the
requirements for the system.
The electronic circuit required for interfacing the computer with the microphones is
illustrated in Figure 1. There are three identical channels (n = 1, 2 and 3), each consisting
of an audio amplifier Qnl, a comparitor Q,2 and a timer Qn. Aside from a common audio
amplifier bias adjustment (R2) and power source, no other parts are shared by the
channels. The audio amplifier and comparitor are packaged with four identical amplifiers
to a chip, so only one chip is needed for all three channels. The timer (Q,,) is a dual
circuit, so two chips and sockets are needed, leaving one unused unit. The 10.2 x 10.3
cm prototype card (Radio Shack 276-154A) on which the circuit is connected, mates with
a plug which is wired as shown in Figure 2. Each channel has an auditory sensitivity
and time delay adjustment located on the front panel, along with an indicator light to
show when the channel is active.
The microphones used are electret versions (Radio Shack) and require application
of voltage. The use of a 1K resistor (Rn1) gives the highest electrical output for a given

Fig. 1. A schematic diagram of the interface electronics, as constructed on a 44-pin
edge-connector prototype card. Connection numbers (in circles) refer to the pins on the
edge connector. All integrated circuits are commercial DIP versions and are mounted
in sockets. Resistors are 1/4 W 5% tolerance and are given in ohms, kilohms (K) and
mehohms (M); capacitors are in microfarads. Cni (Cn, C12, C13) is a disc ceramic, while
Cn2 is a tantalum (observe polarity); 15 V ratings are ample. Variable resistors are
10-turn ceramic trimmers; all but R2 are mounted on the front panel and connected
through the edge connector. Power is drawn from the computer via the games connec-
tor; about 40 mA is required at 5 volts.

644 Florida Entomologist 72(4) December, 1989

sound input, which is maximized since distortion is of no concern to the present study.
Qni is an audio amplifier with a gain of 470X. The positive excursions of the audio signal
carry the input of the comparitor Qn2 across its threshold value (adjustable by panel-
mounted Rn3), producing a negative-going pulse at the input of Qn3. This is a timer
which, when tripped, produces a positive 5 V signal at its output for a duration deter-
mined by Rn5 (panel mounted) in series with Rn4. This timer is normally adjusted to
produce a 1-second pulse. Increasing the values of Rn4, Rn5 or Ca will increase the time
period should a greater range be desired. Light emitting diodes (LEDs) Dn, are used
to visualize the operation of the circuit, and are valuable during initial adjustment and
The interface circuits are mounted in a metal box (14.8 x 20.1 x 4.2 cm) with the
adjustable resistors and LEDs mounted on the front panel and the microphone connec-
tors and cable to the computer extending from the rear. The latter connections are made
via a DB-19 connector which is wired in accordance with the joystick input of the Apple
IIe and IIc computers; if one of these computers is used, the computer cable should be
wired pin for pin to the corresponding DB-19 connector. The Apple II+ requires a
connector which plugs into the game port on the main board and is routed out of a
ventilation slot in the rear of the computer. This connector system can also be used with
the Apple IIe, but not with the IIc or Laser. The interface box draws about 40 mA at
5 volts from the host computer, which is well within the design limits of the port.
The connections between the edge connector and the interface box are shown in
Figure 2. Ji-J3 are sub-miniature phone jacks which mate with corresponding plugs on
the shielded microphone cables. J4 is the 44-pin edge connector for the circuit board, of
which only the 22 numbered pins are used. J5 is a DB-9 female connector mounted on
the interface box, mating to a corresponding male connector on the cable to the com-
puter. J6 is a 16-pin DIP header which mates with the games connector in the Apple
II + or IIe. The off-board components from Figure 1 are also indicated in this schematic


Since BASIC is the resident language in the Apple II series, it was chosen for these
programs; the disk operating system is DOS 3.3. Programs are available to: 1) record
events, 2) determine the proportion of time spent singing by each male for each half-hour
block of recording, and 3) produce a graph of the temporal distribution of calling. In
addition, a file transfer program and a program to read, display and set the clock are
included. All of these programs can be accessed from the main menu which is displayed
upon booting the disk, and all but the file management program return to this menu
upon completion. The main menu is part of the HELLO program which is automatically
run when the program disk is booted.
Upon entry to the data collection program EVENTS, the clock is read to the nearest
second to obtain the time and date. The system collects data by examining the three
inputs and recording the time at which a change in activity is detected at any one of
them. The 1-second timers ensure that no "on" event is missed during the time required
to read the clock and store a record to memory. The timers are not re-triggerable,
however, and actually drop out for a brief period even in the presence of continuous
audio activity (substitution of an N74123 retriggerable monostable multivibrator would
eliminate the "drop out"). Thus the program loop that monitors the inputs takes about
three readings per second, and these three must agree before a change of state is
recorded. When a change in any of the three inputs occurs, the clock is read and the
time (in seconds since midnight) and the values of each input (1 = on, 0 = off) are
stored to an array in memory. This array has provisions for 1300 such records, and the
program will terminate automatically before this limit is exceeded.

Kidder & Sakaluk: Acoustical Activity Recorder

+ 5 71 1 V +5V
2 2 2 PB6
3-- -- 3 PB1
4 -- 4 PB2
J_5I -| 5
-6 --
6 6

JR13 9 -X 9

R23^ --513 R R15 1

21 J


Fig. 2. Wiring diagram of the interface box. J1-J3 are subminiature phone jacks, J4
is the card socket, J5 is a DB-9 male connector for output to the computer, and J6 is a
16-pin DIP header required for connection to the main board on the Apple II+. Also
shown are the off-board components from Figure 1. The LEDs are mounted in Beckman
89B trimmer holders to provide shielding from ambient light.

The program normally terminates at the end of a user-defined recording interval.
Alternatively, unlimited recording may be specified, or the program may be terminated
by keyboard entry regardless of the preset values. When the program terminates, the
data are automatically transferred to the disk if a file name is specified in advance,
without operator intervention. A default filename is taken from the clock when the
program initializes, in the form of the date and year. Thus a set of data which were
obtained starting on April 15, 1988 will be stored to a file called APR15/88. The default
file name can be modified to any legal name, or no selection entered, in which case the
program waits for the operator to supply a name at termination or opt not to store the
data at all. As a protection against storing new data over old, the program searches the
data disk for a file with the proposed name. If one is found, the new file name has an
"X" appended to it, such as APR15/88X. This process is repeated until the new name
(with an appropriate number of X's) is unique. The only way to remove a data file from
disk is by using the DELETE command from BASIC or from the filer.
Upon termination of the recording program, control is passed back to the main
menu. Normally, the analysis program would be selected at this time. This progranl
(LIST.EVENTS) is menu driven, with routines for listing the raw data to the screen
or printer, determining the proportion of time spent singing by each male for each
half-hour block, listing the array of 48 half-hour blocks to the screen or printer, and
half-hour block, listing the array of 48 half-hour blocks to the screen or printer, and

Florida Entomologist 72(4)

saving the array to disk for later display and/or graphical analysis. The analysis program
discards any data recorded before the start of the first even half hour, analyzes data
collected over the subsequent 24 hours, and discards any data after the 24-hour period.
For this reason, the default time for data recording is set to 24.5 hours, ensuring a full
24 hours of usable data. In the analysis, the time at which singing begins is recorded and,
when singing stops, the difference in time is added to the running total for that channel.
At the end of the half-hour period, the time spent calling by each male is divided by
1800 seconds to determine the percent of time spent calling (rounded off to the nearest
0.1%) for that block. To enable analysis of files which contain less than 24 hours of data,
the array is initially cleared to an impossible value (-1%) to distinguish "no singing"
from "no data" in that period.
The analysed data are stored to disk with a file name consisting of the original raw
data file name and an appended "#" sign, to assist in associating each results file with
its raw data file. Upon terminating the program, the graphics program
(GRAPH.EVENTS) is normally selected. This program accesses the results file, can
list it to screen or printer in the same manner as the analysis program, and produces
a high-resolution CRT bar graph which plots calling time (as a percent of time available)
versus the time of day for each channel. Periods for which no data are available (flagged
as -1%) are indicated on the graph.


Before data collection, it is first necessary to calibrate the apparatus. As an initial
adjustment, the threshold of the comparators is set with the microphones removed,
shorting the inputs. Rs3 is adjusted until the associated LED is just extinguished. When
the microphone is replaced, ambient noise will usually trigger the circuit, so a further
decrease in sensitivity is required until the LED is off except when deliberately stimu-
lated. At this point, the timer duration can be set (Rn5); this is best done with a calib-
rated oscilloscope at the output of the timer, or at the positive terminal of the LED.
We adjusted each of the timers to a duration of 0.9 seconds. The microphones are then
installed in the recording chambers, which are rectangular plastic shoe boxes (29.5 X
15.0 cm at the base and 8.5 cm high), appropriately ventilated and with a microphone
inserted through a hole.
The process of adjusting the sensitivities is simplified by having a standard sound
source that can be placed in the recording chamber instead of an insect, and which
generates the same sound level in every chamber. This is accomplished using a high-fre-
quency speaker (RealisticR piezo tweeter 40-1383), that can be placed in the chamber
and driven in parallel with the computer's internal speaker. Due to the high frequencies
involved, a program in machine language (TONE) was used to produce pure tones of
adjustable frequency, duration and interpulse delay; the latter two determine the pulse
repetition rate. This program is called by a BASIC program, MAKE.TONES, which
displays the default parameters, accepts changes and POKE's them to memory, and
calls TONE. The modified parameters subsequently can be stored as part of TONE for
future use. It should be possible to simulate a wide variety of insect calls with this
program, although it is intended for calibration purposes, unlike the systems of Walker
(1982) and Campbell & Forest (1987). To permit the signal amplitude to be varied, an
8-ohm potentiometer is used (Realistic" L-Pad 40-.980), wired such that one side of the
L-Pad provides a constant impedance to the computer cable while the speaker is con-
nected between the wiper and the grounded side.


To test for uniformity of response across the three channels, an experiment was

December, 1989

Kidder & Sakaluk: Acoustical Activity Recorder 647

performed in which the three microphones were bundled together and placed in the
same chamber with a single male cricket, Gryllodes supplicans Walker (Orthoptera:
Gryllidae). Over a 24-hour recording period, there were several half-hour blocks during
which singing was continuous (100%), many blocks in which there was no singing, amd
many with intermediate values. Only 13 of the 48 half-hour periods showed any differ-
ence between channels, with the greatest error being a 0.6% (10.8-second) difference
in a period of low activity (0.6, 1.0 and 0.4% for the three channels, respectively). Ten
of the 13 periods had a difference of only 0.1-0.2% (1.8-3.6 seconds). Careful alignment
of the circuits with respect to sensitivity and timer duration resulted in a second trial
in which only 10 of the 48 half-hour periods showed any difference between channels,
with the error never exceeding 0.2% (3.8 seconds).
Because the crickets frequently change their location within the recording chambers,
sensitivities must be adjusted such that microphone response does not vary as a conse-
quence of such movement. To determine if the placement of the microphone relative to
the cricket had any influence on microphone response, the three microphones were
placed in different locations in the same chamber and oriented in different directions.
In a 24-hour recording period, 11 of the 48 sampling periods showed a difference be-
tween channels, with the error never exceeding 0.3% (5.4 seconds).
Finally, the apparatus was set up for an experiment employing three recording
chambers, each containing a single male G. supplicans and provisioned with ample food,
water and shelter. Microphone cables, approximately three meters in length, permitted
the chambers to be widely separated, thereby preventing acoustical activity in one cage
from being detected at adjacent microphones. The results of this experiment are shown
in Figure 3. Although there was some variation between males, calling activity peaked
shortly after "lights off", remained constant throughout most of the dark portion of the
photoperiod, and ceased shortly before "lights on". These results conform closely to
field observations of G. supplicans (Sakaluk 1987).


The ease and accuracy of data collection using our apparatus make possible a range
of experiments which would be extremely laborious or essentially impossible using
standard observational sampling methods (Altmann 1974). Three crickets can be moni-
tored for acoustical activity continuously over a 24-hour period, and the system meas-
ures not only the duration of activity, but its temporal distribution. The use of half-hour
analysis periods was an arbitrary choice; appropriate program modifications can provide
any appropriate interval.
For some studies, the restriction to three channels of input may be a limitation. The
interface electronics will support a fourth channel involving no additional active compo-
nents, since an unused section of each chip is available. The Apple II + has a cassette
input, similar to the pushbutton inputs, which is mapped to a specified memory location
(49256, $C060) and could be specified as PB3. However, this input is capacitor coupled
and will not respond to direct current, so that the Apple main circuit board would have
to be modified to enable use of this input.
It should also be possible to use a parallel interface card such as the Apple Parallel
Interface Card to access up to eight inputs, using one digit for each input. If used in
conjunction with the three or four inputs available through the games/cassette inputs,
a total of 12 event channels could be monitored, with a corresponding increase in the
complexity of the interface circuit. Alternatively, by employing an appropriate multi-
plexing circuit, a single input line could be used to signal a change in activity (i.e., on
or off) while three others would be sufficient to specify which channel of the eight was
being monitored. In either scheme, a more efficient data storage system would be

Florida Entomologist 72(4)








lights off

8 12 16

lis 20 24
lights on

TIME (hours)

Fig. 3. Temporal pattern of calling of three decorated crickets, Gryllodes supplicans,
monitored over a 24-hour period. Calling time is shown as a percent of the total time
available for each half-hour block.

required. At present, the data are stored as an array of three integers, requiring six
words per record. Since only one bit is required to specify the information for each
channel, it would be possible with additional programming to compress 16 channels of
data into a single integer representation (two 8-bit words).
Most of these modifications would, of course, be unnecessary with the purchase of
a more powerful (and more expensive) computer. However, our selection of the Apple
II+ was deliberate, since we sought to utilize a common and inexpensive computer that
is often found in departmental stockrooms, having been retired from more demanding
service. In fact, the existence of this computer and similar computers as surplus items,
or at low cost on the used market, is an attractive feature of this apparatus. The authors
would be pleased to correspond with others interested in the further development or
implementation of this system. Since the programs are too long for publication, we
would be happy to supply listings or copies of them on request.



December, 1989


0- ----

Giesel et al.: Comparative Energetics of Drosophila


GWK was supported by a grant from the National Institute of Health. We thank
Angelo Capparella for providing the Spanish translation of the abstract, and an anony-
mous reviewer for helpful comments on the manuscript.


ALTMANN, J. 1974. Observational study of behavior: sampling methods. Behaviour
49: 227-267.
CADE, W. H. 1981. Alternative male strategies: genetic differences in crickets. Sci-
ence 212: 563-564.
CAMPBELL, D. J., AND J. FOREST. 1987. A cricket-song simulator using the 68705
single-chip microcomputer. Behavior Research Methods, Instruments, and Com-
puters 19: 26-29.
ROST, R., AND H. W. HONEGGER. 1987. The timing of premating and mating be-
havior in a field population of the cricket Gryllus campestris L. Behav. Ecol.
Sociobiol. 21: 279-289.
SAKALUK, S. K. 1987. Reproductive behaviour of the decorated cricket, Gryllodes
supplicans (Orthoptera: Gryllidae): calling schedules, spatial distribution, and
mating. Behaviour 100: 202-225.
SAKALUK, S. K., G. K. MORRIS, AND W. A. SNEDDEN. 1987. Mating and its effect
on acoustic signalling behaviour in a primitive orthopteran, Cyphoderris strepi-
tans (Haglidae): the cost of feeding females. Behav. Ecol. Sociobiol. 21: 173-178.
WALKER, T. J. 1982. Sound traps for sampling mole cricket flights (Orthoptera: Gryl-
lotalpidae: Scapteriscus). Florida Entomol. 65: 105-110.
WALKER, T. J. 1983. Diel patterns of calling in nocturnal Orthoptera, pp. 45-72 in D.
T. Gwynne and G. K. Morris [eds.] Orthopteran Mating Systems: Sexual Compe-
tition in a Diverse Group of Insects. Westview: Boulder, CO.


Department of Zoology, University of Florida, Gainesville, Florida 32611


The metabolic rates of wild-caught adult female Drosophila melanogaster measured
at 22C are significantly greater than those of sympatric Drosophila simulans. Simi-
larly, the temperature-specific metabolic rates, measured at 18, 22, and 250C, in labora-
tory-reared granddaughters of the wild-caught D. melanogaster are greater than those
of the laboratory-reared granddaughters of the wild-caught D. simulans females. These
genetically encoded differences in metabolic rate between the two species may be re-
lated to differences in fecundity and seasonality.


La tasa de metabolismo de hembras salvajes atrapadas de Drosophila melanogaster
medidas a 22C fu6 significantemente mayor que aquellas de Drosphila simulans sim-
pAtricas. Similarmente, la tasa de metabolismo de temperature especifica, medidas a


Florida Entomologist 72(4)

18, 22, y 25C, en nietas de hembras salvajes de D. melanogaster criadas en el
laboratorio, fu6 mayor que el de nietas de hembras salvajes de D. simulans criadas en
el laboratorio. Estas diferencias del c6digo gen6tico en la tasa de metabolismo entire las
dos species pudieran estar relacionadas a diferencias de fecundidad y estacional.

Drosophila melanogaster Meigen and Drosophila simulans Sturtevant are sibling
species that can be separated only by genital characteristics of males and the shapes of
egg respiratory filaments (Sturtevant 1921). Both species are cosmopolitan and are
found throughout the continental United States (Sturtevant 1921). However, collecting
experience indicates that their geographic and seasonal distributions differ (unpublished
observations). Drosophila simulans is primarily a southern species, uncommon in collec-
tions from latitudes above 30N. Drosophila melanogaster, although occurring in the
southern United States, has a more northerly distribution. Both species are found in
north-central Florida: D. simulans is common throughout the year, but D. melanogas-
ter is less abundant and appears primarily during the spring and fall. In seeming accord
with this distributional difference, life histories also differ. Under laboratory conditions,
oviposition of D. melanogaster begins on the first or second day after eclosion, builds
to a peak of about 120 eggs per day on days 7-9, then declines (Giesel et al. 1982a, b).
Female lifespan is 20-40 days, depending on culture temperature. In contrast, D. simu-
lans's reproductive output is about 60% lower on a per-day basis, with no obvious
age-related peak, and females may live for 40-60 days depending on culture temperature
(Murphy et al. 1983).
Given the the positive correlations between metabolic rate and fitness among popu-
lations of D. melanogaster (Marstellar 1985), and between fecundity and metabolic rate
among genotypes of D. simulans (unpublished observations), we expected D.
melanogaster to have a higher rate of metabolism than D. simulans. Here we test this
hypothesis using flies collected in Gainesville, Florida.


Two samples of flies were taken from Gainesville, Florida during the fall of 1988.
The first, collected September 28 and 29, consisted of 4 female D. melanogaster and 13
female D. simulans; the second, collected on October 27-29, included 13 female D.
melanogaster and 30 female D. simulans. The flies were attracted to traps containing
fermenting bananas. Isofemale lines were established from each collected female. Cul-
tures were maintained at 11-h light:13-h dark and 23-24C in vials containing 15 ml of
medium consisting of corn meal, sucrose, and brewers yeast. Cultures were supple-
mented with live yeast.
Rates of metabolism at 22C of the surviving wild-caught October females were
determined 2 or 3 days following their capture. In addition, we measured the rates of
metabolism of laboratory-reared granddaughters of the females collected in September
and October. Three granddaughters were paired with single males from each isofemale
line following eclosion and then were placed in separate vials of fresh medium. Four
days later, the females were transferred to metabolism chambers and incubated in the
dark at 180C, 22C, or 25C for approximately 6 h.
Rates of metabolism were determined on individual flies held in the dark using
"closed system" metabolic chambers (Vleck 1987) consisting of disposable 30 cc syringes.
Complete darkness, which may reduce flight and other locomotory activities, was assured
by sealing the metabolic chambers in an incubator. At the end of a run, approximately
6 h, the fractional 02 concentration of the syringe gas was determined with an Ametek
Applied Electrochemistry S-3A Oxygen Analyzer (Pittsburgh) supplied with a model


December, 1989

Giesel et al.: Comparative Energetics of Drosophila 651

N-22M Sensor. A 6-h run was chosen because our previous measurements indicate that
the magnitude of the decrease in oxygen fraction allows accurate measurement and that
body weight and metabolic rate do not decrease during this period of time. Three or 4
syringes without flies were treated exactly as were experimental syringes and served
as controls for each series of measurements. A more complete description of our method
of metabolic rate measurement is found in Giesel et al. (1989).
Oxygen consumption (Vo2) in pl/h was calculated using the following equation (Vleck

Vo2 = V(FIo,-FEo,)/(1 FEo,)t,

where V is the initial volume of dry C02-free room air in the syringe at STP, Flo2 and
FEo2 are the 02 fractions within the syringe at the beginning and end of the run, and
t is the duration of the run in hours.
The flies were dried for 3 days in a 600 oven and weighed to the nearest 0.002 mg
using a Cahn electrobalance. Metabolic rates were adjusted with analysis of covariance
(as recommended by Packard & Boardman 1987) to a common body weight of 0.50 mg,
the average dry weight of all flies in this study. Size variation of the analyzed flies
(Table 1) emphasizes the need to adjust for differences in size. The significance of
species differences was tested with 1-tailed t-tests.


The average rates of metabolism of field-collected October females measured at 22C,
3.79 pCl 02/0.5 mg-h in D. melanogaster and 3.26 01 02/0.5 mg-h in D. simulans, were
significantly different (P < 0.05).
Similar species differences in rates of metabolism measured at 220C were obtained
for laboratory-reared granddaughters from both the September and October samples.
In the September sample, average rates of metabolism of D. melanogaster and D.
simulans were 6.4 Wl 02/0.5 mg-h and 4.4 t1 02/0.5 mg*h, respectively (P < 0.0001).


x s n

Field-collected (October 1988)
D. melanogaster 0.339 0.110 6
D. simulans 0.306 0.079 28
Laboratory-reared (September 1988
D. melanogaster 0.531 0.090 12
D. simulans 0.523 0.056 41
Laboratory-reared (October 1988
D. melanogaster 0.515 0.061 29
D. simulans 0.505 0.061 54

Florida Entomologist 72(4)

In the October sample, average rates of metabolism of D. melanogaster and D. simu-
lans were 6.5 pl 02/0.5 mgoh and 6.1 L 02/0.5 mg*h, respectively (P < 0.05). Adult
female D. melanogaster also have higher rates of metabolism at 18C and 25C than do
adult female D. simulans (P < 0.05, Figures 1 and 2).
The reasons for the large deviation between the metabolic rates of field-collected
and laboratory-reared flies of the same species were not investigated but may be due
to (1) acclimation differences, if field temperatures were higher than laboratory rearing
temperatures or (2) nutritional differences, if, as the data in Table 1 suggest, field-col-
lected flies were food-limited as larvae.

The rates of metabolism measured in this study are not "standard rates of
metabolism" (Hill and Wyse 1989), as the experimental protocol did not preclude
locomotory activity. Although the flies were incubated in complete darkness to reduce
activity, diel cycles in oxygen consumption still persist (Anderson et al., in press). Such
rhythmic changes in oxygen consumption may represent variation in locomotory activity
that corresponds to activity cycles in nature. This qualification should not invalidate the
species comparison because measurements were made on both species exposed to the
same conditions.















Incubation Temperature (C)

Fig. 1. Average metabolic rates of granddaughters of September wild-caught
females measured at 18, 22 and 25C, + standard error. Upper line-D. melanogaster,
lower line-D. simulans.


December, 1989


Giesel et al.: Comparative Energetics of Drosophila








Incubation Temperature (*C)

Fig. 2. Average metabolic rates of granddaughters of October wild-caught females
measured at 18, 22 and 25, standard error. Upper line-D. melanogaster, lower
line-D. simulans.

Metabolic rates of D. melanogaster are higher than those of D. simulans, an obser-
vation that is consistent with a previous comparison of these species (Anderson et al.,
in press). Because the same relative rates were found in wild-caught females and their
laboratory-reared granddaughters, this difference must be highly heritable. For some
important morphological characters such as wing length and body size, within-species
population differences in wild-caught flies dwindle, disappear, or are even reversed in
their laboratory-reared descendents, casting doubt on the extent of genetic determina-
tion and selectability of the trait (Prout 1958, Levins 1969).
The persistent and genetically encoded difference in metabolic rates between the
two species may be related to fecundity and seasonality differences. Drosophila
melanogaster has higher per-day fecundity than does D. simulans but has a much
shorter life-span. Drosophila melanogaster's higher rate of metabolism may be neces-
sary to support a higher rate of egg production but may result in reduced longevity.
Rate of metabolism is positively correlated with rate of egg laying during the first few
days of reproduction (Marstellar 1985 and unpublished observations). Also, individuals
of D. melanogaster are most common in the late fall and early spring in Florida. High
rates of metabolism may be required for rapid larval development and high fecundity,
both of which build populations quickly during short yearly population flushes.
Drosophila simulans is commonly observed during every month in Florida. High rates
of fecundity are apparently not as critical to population persistence as is the ability to
produce eggs over a long period of time. A low metabolic rate may be sufficient to

. I


Florida Entomologist 72(4)

maintain D. simulans's characteristic oviposition rate and may enhance chances of an
extended lifespan, particularly during periods of food deprivation.


ANDERSON, J. F., C. A. LANCIANI, AND J. T. GIESEL. Diel cycles and measurement
of metabolic rate in Drosophila. Comp. Bioch. Physiol. In press.
GIESEL, J. T., P. A. MURPHY, AND M. N. MANLOVE. 1982a. An investigation of the
effects of temperature on the genetic organization of life history traits in three
populations of Drosophila melanogaster, pp. 189-207 in H. Dingle & J. P. Heg-
mann (eds.), Evolution and genetics of life histories. Springer-Verlag, New York.
GIESEL, J. T., P. A. MURPHY, AND M. N. MANLOVE. 1982b. The influence of tem-
perature on genetic interrelationships of life history traits in a population of
Drosophila melanogaster: What tangled data sets we weave. Amer. Nat. 119:
GIESEL, J. T., C. A. LANCIANI, AND J. F. ANDERSON. 1989. Larval photoperiod
and metabolic rate in Drosophila melanogaster. Florida Entomol. 71: 123-128.
HILL, R. W., AND G. A. WYSE. 1989. Animal physiology. Harper and Row, New
LEVINS, R. A. 1969. Thermal acclimation and heat resistance in Drosophila species.
Amer. Nat. 103: 483-499.
MARSTELLAR, P. A. 1985. Temperature heterogeneity and geographic variation in
life history patterns of Drosophila melanogaster. Ph.D. dissertation, University
of Florida, Gainesville, Florida.
MURPHY, P. A., J. T. GIESEL, AND M. N. MANLOVE. 1983. Temperature effects on
life history variation in Drosophila simulans. Evolution 37: 1181-1192.
PACKARD, G. C., AND T. J. BOARDMAN. 1987. The misuse of ratios to scale physiolog-
ical data that vary allometrically with body size, pp. 216-236 in M. E. Feder, A.
F. Bennett, W. Burggren, and R. B. Huey (eds.), New directions in ecological
physiology. Cambridge University Press, Cambridge.
PROUT, T. 1958. A possible difference in genetic variance between wild and laboratory
populations. Drosophila Inform. Serv. 32: 148-149.
STURTEVANT, A. H. 1921. North American species of Drosophila. Carnegie Institu-
tion of Washington, Washington, D.C.
VLECK, D. 1987. Measurement of 02 consumption, CO2 production, water vapor pro-
duction in a closed system. J. Applied Physiol. 62: 2103-2106.

December, 1989

Walker & Forrest: Mole Cricket Phonotaxis


Department of Entomology and Nematology
University of Florida
Gainesville, Florida 32611-0143


The sound pressure level of the natural call of S. acletus is 70 to 90 dB (measured
at 15 cm). Within this range louder males attract many more conspecifics than do
quieter males. Because traps that broadcast simulated calling songs at >90 dB catch
enormous numbers of mole crickets, the upper limit of greater phonotaxis to higher
sound levels is important to sound trap design. In three series of tests of traps broad-
casting synthetic calling songs differing by 12 dB, the louder trap captured 3 to 9 times
as many mole crickets as the quieter one. The effect was significantly greater in trials
of 94 vs 106 dB and of 106 vs 118 dB than in trials of 116 vs 128 dB, but we failed to
find the upper limit we were seeking. At all intensities a greater proportion of females
than males landed within 0.76 m of the speaker.


La presi6n del sonido del llamado natural de S. acletus es de 70 a 90 dB (medido a
15 cm). Dentro de esta gama, los machos que emiten sonido mis alto atraen muchos
mis coespecificos que los machos mas callados. Debido a que las trampas que emiten
cantos simulados a >90 dB capturan cantidades enormes de grillotopos, el limited
superior de mAs fonotaxis a niveles de sonidos altos es important en el disefio de
trampas de sonido. En tres series de pruebas con trampas emitiendo cantos sint6ticos
diferiendo por 12 dB, la trampa mas alta capture de 3 a 9 veces mas grillotopos que la
mAs baja. El efecto fue significativamente mayor en pruebas de 94 contra 106 dB y de
106 contra 118 dB que en las pruebas de 116 contra 128 dB, pero fracasamos en encontrar
el limited alto que estAbamos buscando. A todas las intensidades, hubo una mayor prop-
orci6n de hembras que de machos que estaban dentro de 0.76 m del autoparlante.

Trapping flying mole crickets (Scapteriscus spp.) that land near electronic renditions
of mole cricket songs is an effective means of monitoring flight activity and of securing
specimens for research (Walker 1982, 1988). The numbers captured, sometimes
thousands in less than 1 hr, are great enough to suggest that sound traps could be useful
in control of pest mole crickets.
An important finding from previous studies of mole cricket phonotaxis is that the
more intense the call, the greater the number of mole crickets attracted to it. This is
true with natural variation in the loudness of calling mole crickets, 70 to 90 dB SPL
(sound pressure level re 20 pPa measured at 15 cm above the sound source) (Forrest
1983). It is also true with experimentally varied electronic imitations of mole cricket
calls. Ulagaraj & Walker (1975) reported that at SPL's between 70 and 106 dB the
numbers of mole crickets captured, relative to a 100 dB standard, approximately dou-

'Current address: National Center for Physical Acoustics, University of Mississippi, University, MS 38677.

Florida Entomologist 72(4)

bled with each 6 dB increase. Above 106 dB, increases in captures were slight and not
statistically significant. However, Forrest (1980), using improved sound generating
equipment and more replication, found that a 6 dB increase within the range 101 to 111
dB gave a 5.7-fold increase in numbers caught (95% C.I. = 5.2 to 6.3). Forrest & Green
(1989) showed that this degree of increase was predicted by a simple physical model
based on flying mole crickets choosing the sound source that had the greatest SPL at
their sound receptors.
The studies reported here extend the upper range of SPL's tested to 128 dB, 10 dB
higher than any used more than once by Ulagaraj & Walker (1975) and 17 dB above the
range used by Forrest (1980). Unlike the previous studies, our traps captured mole
crickets landing as far as 1.83 m from the sound source and segregated the catch into
those landing within the 0.76-m radius of a standard mole cricket trap (Walker 1982)
and those landing up to 1.07 m farther out. We hoped to find the limits of higher
intensity resulting in greater catch and to determine if very high intensities decreased
the relative frequency of those landing within the standard catching area.


Two mole cricket traps, each consisting of a 3.66 m diameter circular swimming pool
with a 1.52 m diameter child's wading pool placed at center, were installed 2 m apart
at University of Florida's Green Acres Farm, near Gainesville. Enough water was
added to cover the bottoms of the pools. From the center of each trap, identical battery-
powered sound synthesizers broadcast simulated calling song of Scapteriscus acletus
(2.7 kHz carrier turned on and off at 50 Hz with a 50% duty cycle; see Walker 1982).
SPL's of the two units were set 12 dB apart, using a Bruel & Kjaer model 2219 sound
level meter 15 cm above the sound source. Sound synthesizers were switched on at
sunset and off ca. 2 hr later, after S. acletus flights had ceased. Mole crickets that
landed within the pools swam about on the water's surface until removed, sexed, and
Tests were run nightly, weather permitting, 8 May to 4 June 1980. In each series
of tests, the location of the high SPL broadcast was switched between the two traps at
least every second night; synthesizers were alternated between high- and low-intensity
duty nightly. The first series of tests (8 to 13 May, n= 6) compared 106 and 118 dB.
The substantial differences in catches, contrasting with the results of Ulagaraj and
Walker (1975), led us to use 94 and 106 dB for the second series (14 to 24 May, n = 9).
The synthesizers for these two series were standard "artificial crickets" (Walker 1982).
In the third series (26 May to 4 June, n= 6), we used more powerful versions of the
same device to compare 116 and 128 dB. These "super crickets," made by William
Oldacre, the designer of the standard ones, had more batteries, a larger amplifier, and
two 7.5 cm speakers 1 cm apart. Intensity was measured 15 cm above the 1 cm bridge
between the two speakers. Hearing protectors were required when measuring inten-
sities above 106 dB.


Traps with higher sound levels caught significantly more S. acletus than similar
traps operated 12 dB lower (Fig. 1). The high range tests (116 vs: 128 dB) produced
catch ratios (no. in high dB trap/no, in low dB trap) that were significantly lower than
the ratios of the other two ranges (chi square, P<0.001). Within the low and medium
range tests (94 vs 106 and 106 vs 118), but not in the high range tests, females showed
a significantly stronger preference for the high dB trap than did males. The catch ratios
for males and females in the low range tests were 6.7 and 9.1, respectively. Correspond-
ing values in medium and high range tests ere 7.9 and 10.1, and 2.6 and 2.9.


December, 1989

Walker & Forrest: Mole Cricket Phonotaxis

Low range
(94 vs 106 dB)


10 i






Medium range
(106 vs 118 dB)

3829 6722 10551
P(m=f) < 0.001


High range
(116 vs 128 dB)

686 4518 5204
P(m=f) > 0.75

Fig. 1. Relative effectiveness of paired traps baited with synthetic S. acletus calls
differing by 12 dB. Bars show catch ratios-i.e., (no. S. acletus caught in high dB
trap)/(no. caught in low dB trap). Total captures and probabilities of male ratio equalling
female ratio (chi square) are at bases of bars.

The majority of mole crickets captured landed within the 0.76-m radius of a standard
mole cricket trap (Table 1). In the low and medium range tests, the catch ratios were
significantly higher than for mole crickets captured landing farther out. In the high
range tests, the higher catch ratio was for the outer ring.
In both traps in every comparison, females were significantly more concentrated in
the central 1.5 m of the trap than were males (Fig. 2). Landing density ratios-i.e., the
density (no./m2) in the inner circle of the trap divided by the density in the outer
ring-were 2.5 to 5.6 for males and 4.8 to 14.3 for females.
In the low and medium range tests, landings of males and females in the trap with
the higher SPL were significantly more concentrated centrally than landings in the trap
with the lower SPL (chi square, P<0.05). In the high range tests, this effect disappeared
for males (P>0.10) and reversed for females (P<0.001) (Fig. 2).


Inner circle (0.76m radius) Outer ring (0.76-1.83 m)
Catch Catch
Test range Low High ratio Low High ratio

94 vs 106 dB 371 4002 10.8a 345 1888 5.5
106 vs 118 dB 514 5593 10.9a 522 3922 7.5
116 vs 128 dB 761 1902 2.5 581 1960 3.4b

aCatch ratio higher than in outer ring (chi square; P<0.001).
bCatch ratio higher than in inner circle (chi square; P<0.001).

2003 4603 6606
P(m=f) < 0.001


658 Florida Entomologist 72(4) December, 1989

Low range
O males
.9 females
1 -12

Co Medium range High range

-J 4

94 dB 106db 106db 118dB 116dB 128dB

Fig. 2. Relative densities of S. acletus landing in central and outer portions of traps
baited with synthetic S. acletus calls. For each SPL in each range, bars show landing
density ratios-(landing density in central circle)/(landing density in outer ring)-for
males and females. In every trap females were significantly more concentrated centrally
than were males (chi square, P<0.001).


We failed in our quest of a limit to higher intensities catching more S. acletus (Fig.
1). The reduction in the degree of effect in tests of 116 vs 128 dB can be attributed to
intensity effects diminishing at such high SPL's, to crickets attracted to the louder trap
landing in the adjacent softer trap, or to our use of two-speaker artificial crickets.
Whether SPL's above 128 dB would be even more effective is probably of little practical
importance, because equipment to produce such SPL's is not readily available and be-
cause of potential problems with hearing damage, noise-nuisance complaints, and law
Our data on landing patterns confirmed a phenomenon reported in earlier studies--
viz., males are more dispersed in their landing sites relative to the sound source than
are females (Forrest 1981, Matheny et al. 1983). Males landing at the sound of another
male are probably less likely to benefit from entering the calling male's burrow than
are females; however, the only study of behavior of mole crickets landing near a burrow
found no significant sexual difference in the frequency of entering (Forrest 1983).
Effects of SPL on landing patterns seem complex (Fig. 2), and our switching to
two-speaker synthesizers for the 116 vs 128 dB tests makes it unprofitable to compare
those results with results from tests in the other two ranges. In the 94 vs 106 and in
the 106 vs 118 tests, the landing density ratios of both males and females were signifi-
cantly greater at the higher SPL. That this was a relative rather than an absolute effect
is shown by comparing landing density ratios at 106 dB paired with 94 dB and with 118
dB (Fig. 2). For both males and females the ratios at 106 dB differed under these two
conditions (chi square, P<0.001. A possible reason for higher landing density ratios at
the higher intensity is that a portion of the crickets landing in the low dB trap were
attracted to the high dB trap but landed a few meters away. Matheny et al. (1983), who
studied landing patterns about a single sound source, reported that landing densities 3
m from the sound source were still 10 to 20% of those within 0.75 m. The edge of the
low SPL sound trap in our experiments was only 3.83 m from the synthesizer in the

Walker & Forrest: Mole Cricket Phonotaxis 659

high intensity trap. Any "cross-catching" that occurred would diminish the landing
density ratio in the low SPL trap more than in the high SPL trap (because many more
cross-caught crickets would land in the low intensity trap). Cross catch would also
reduce the catch ratios shown in Fig. 1.


We thank Jackie Belwood and Pat Parkman for criticizing the manuscript. Fla.
Agric. Exp. Stn. Journal Series No. R-00008.


FORREST, T. G. 1980. Phonotaxis in mole crickets: its reproductive significance.
Florida Entomol. 63: 45-53.
FORREST, T. G. 1981. Acoustic behavior, phonotaxis, and mate choice in two species
of mole crickets (Gryllotalpidae: Scapteriscus). M.S. thesis, Univ. Florida,
FORREST, T. G. 1983. Calling songs and mate choice in mole crickets, pp. 185-204 in
D. T. Gwynne and G. K. Morris (eds.), Orthopteran mating systems: sexual
selection in a diverse group of insects. Westview Press, Boulder, Colo.
FORREST, T. G., AND D. M. Green. 1989. Sexual selection and female choice in mole
crickets (Scapteriscus: Gryllotalpidae): modeling the effects of intensity and male
spacing. Anim. Behav. (submitted).
MATHENY, E. L., JR., R. L. KEPNER, AND K. M. PORTIER. 1983. Landing distribu-
tion and density of two sound-attracted mole crickets (Orthoptera: Gryllotalpidae:
Scapteriscus). Ann. Entomol. Soc. America 76: 278-281.
ULAGARAJ, S. M., AND T. J. WALKER. 1975. Responses of flying mole crickets to
three parameters of synthetic songs broadcast outdoors. Nature 253: 530-532.
WALKER, T. J. 1982. Sound traps for sampling mole cricket flights (Orthoptera: Gryl-
lotalpidae: Scapteriscus). Florida Entomol. 65: 105-110.
WALKER, T. J. 1988. Acoustic traps for agriculturally important insects. Florida
Entomol. 7: 484-492.

Florida Entomologist 72(4)


Biology Department, Fordham University
Bronx, NY 10458 USA
Research Associate
Florida State Collection of Arthropods
Florida Department of Agriculture and Consumer Services
Gainesville, FL 32602 USA


Itamuton stangei n. sp. attacks pupae of the central Chilean antlion, Elicura
litigator Navas. It is the first New World species of Ichneumonidae known to parasitize
Myrmeleontidae. Itamuton stangei n. sp. is described from males and females. It resem-
bles the sympatric I. rufitibia (Spinola) but is shorter and stouter in bodily proportions
and has less strongly projecting propodeal cristae.


Itamuton stangei n. sp. ataca las pupas del mirmele6ntido centro-chileno, Elicur
litigator Navas. Es esta la primer vez que un icneum6nido haya sido criado en el Nuevo
Mundo, como parasito de Myrmeleoitido. Itamuton stangei n. sp. se asemeja a la especie
simpAtrica, Itamuton rufitibia (Spinola), pero tiene el cuerpo mas corto y robusto y las
crestas del propodeo menos proyectantes.

Itamuton Porter (1987) ranges through subequatorial South America with species
in the Andean Puna (I. townesorum (Porter)), in the Peruvian West Andean slopes and
Coastal Desert (I. occidens (Porter)), in central and south-central Chile (I. rufitibia
(Spinola)), and also across the ecotone at the austral end of South America between
Nothofagus forest and Patagonian Steppe (I. magallanes (Porter)).
This genus belongs to the Subtribe Ischnina of the Tribe Mesostenini (Townes 1969).
Its diagnostic features include the filiform female antenna; the long malar space (0.6-1.6
as long as basal width of mandible); the little elevated but sharp occipital carina; the
dorsally much narrowed areolet; the reclivous 2nd recurrent vein that is outbulged on
its upper 0.5; the axillus vein which runs close to the anal margin of its wing; the
unarmed lower prepectus; the conspicuous notauli that reach 0.5 or more the mesoscutal
length; the prominent and polished groove that descends from the hind coxal base; the
more or less traceable basal and apical transverse carinae of the propodeum on which
the apical trans-carina reaches far forward medially; the elongate propodeal spiracle;
the absence of a lateral tooth at the base of the petiole; and the sparsely setose female
2nd gastric tergite.
Itamuton stangei provides the 1st host data for its genus and is the only New World
ichneumonid known to parasitize Myrmeleontidae. However, most ischnine genera
exploit lepidopterous hosts (Porter 1967, 1987), so that I. stangei may constitute a
trophic novelty within its genus. Certainly, the high Andean I. townesorum (Porter)
and the subantarctic I. magallanes (Porter) inhabit areas where Myrmeleontidae are


December, 1989

Porter: Itamuton stangei

unlikely to occur. Furthermore, species of the related genera Phycitiplex and Oecetiplex
do parasitize Lepidoptera in such families as Phycitidae and Psychidae.


1. Mesoscuum mat with some dully shining areas, its sculpture consisting of
small punctures and of fine wrinkling; malar space 0.9-1.1 as long as basal
width of mandible ............................................... ........................... 2
1'. Mesoscutum highly polished with abundant small and sharp punctures that
have at least narrow smooth interspaces; malar space 0.7-1.6 as long as basal
w idth of m andible ................................................................................. 3
2. Ovipositor upcurved; temple 0.4-0.5 as long as eye in dorsal view; no red
markings on gaster; female flagellum with a white band; female gaster
wholly black ........................................................ I. townesorum (Porter)
2'. Ovipositor very slightly upcurved; temple 0.2-0.3 as long as eye in dorsal
view; gaster with red extensively on at least tergites 1-3; flagellum without
a white band; female gaster with white on tergite 4 and those succeeding
................................................................................ I. occidens (Porter)
3. Flagellum without a white band: ground color of 2nd and following gastric
tergites pale red with some brownish suffusion; wings hyaline; malar space
of female 1.4-1.6 as long as basal width of mandible, of male 1.1-1.3 as long
as basal width of mandible; ovipositor gently upcurved, its nodus high and
its tip in profile straight or slightly concave from nodus to apex ............
......................................................................... I. m agallanes (Porter)
3'. Flagellum with a white band; gastric tergites with ground color black; malar
space of female 0.7-0.9 as long as basal width of mandible, of male 0.6-0.7 as
long as basal width of mandible; ovipositor straight with a low but distinct
nodus and convex in profile between nodus and apex .................................. 4
4. Malar space in female 0.6-0.7 as long as basal width of mandible; temple in
female 0.2-0.3 as long as eye in dorsal view; mesoscutum 0.8-0.9 as long as
wide; female propodeum 0.4-0.5 as long as high in lateral view, male pro-
podeum 0.7 as long as high; propodeal cristae of female broadly subcuneate
and little projecting; female postpetiole 1.7-2.2 as wide apically as long from
spiracle to apex; male 2nd gastric tergite stout and gradually widened
toward apex, 0.6 as wide apically as long ............................ I. stangei n. sp.
4'. Malar space in female 0.8-0.9 as long as basal width of mandible; temple of
female 0.4-0.5 as long as eye in dorsal view; mesoscutum about as long as
wide; female propodeum with projecting cristae and 0.6-0.7 as long as high,
male propodeum 0.8 as long; female postpetiole 1.2-1.4 as wide apically as
long from spiracle to apex; male 2nd gastric tergite parallel-sided, slender,
0.3-0.4 as wide apically as long ..................................... I. rufitibia (Spinola)

Itamuton stangei Porter, New Species
(Fig. 1, 2)

FEMALE: Color: antenna black with weak brown staining and with a ventrally duller
and partly interrupted white band on flagellomeres 4-5 and base of 6; head, mesosoma,
and gaster black with white markings as follows: narrow band on facial orbit and lower
0.3 of frontal orbit; narrow band on hind orbit except near top and bottom; large but
unattached blotch in malar space; small round blotch medially a little before base of
mandible; pair of transverse marks on dorsum of pronotal collar; narrow stripe exter-
nally on pronotal humerus; much of tegula; triangular blotch on basal angle of scutellum;

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