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Title: Florida Entomologist
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Language: English
Creator: Florida Entomological Society
Publisher: Florida Entomological Society
Place of Publication: Winter Haven, Fla.
Publication Date: 1994
Copyright Date: 1917
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Subject: Florida Entomological Society
Entomology -- Periodicals
Insects -- Florida
Insects -- Florida -- Periodicals
Insects -- Periodicals
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Shelly: Methyl eugenol consumption byBactrocera dorsalis 201


CONSUMPTION OF METHYL EUGENOL BY MALE
BACTROCERA DORSALIS (DIPTERA: TEPHRITIDAE):
LOW INCIDENCE OF REPEAT FEEDING


TODD E. SHELLY
Hawaiian Evolutionary Biology Program
University of Hawaii
Honolulu, HI 96822


ABSTRACT

The tendency of male Bactrocera dorsalis (Hendel) to re-visit a methyl eugenol
source following initial exposure was examined. The first field test investigated the
effect of duration of exposure on subsequent capture probability. "Treated" males
were allowed to feed on methyl eugenol for 30 s or had access to methyl eugenol for
1 h, 4 h, or 24 h immediately prior to release. Capture probabilities (1%-4%) did not
differ significantly among the different treatments but were significantly below that
(22%) recorded for "control" (unexposed) males. In a second field test, treated males
were released 7 d, 21 d, or 35 d after an initial exposure (2 h) to methyl eugenol. Cap
ture probabilities (11%-18%) did not differ significantly among the different treat
ments but were significantly below that (34%) recorded for control males. Laboratory
tests yielded similar results as both the incidence and duration of re-feeding on me
thyl eugenol were uniformly low for males held 7 d, 21 d, or 35 d after their initial ex
posure. By exposing sterile males to the lure prior to release, it may be possible to
combine programs of male annihilation and sterile insect release. The present find
ings also suggest that the effectiveness of male annihilation efforts may be reduced
in areas where wild males have consumed sufficient amounts of methyl eugenol from
natural sources.
Key Words: Oriental fruit fly, parapheromone.

RESUME

Se estudi6 la tendencia de las visits continues del macho de Bactrocera dorsalis
a una fuente de methyl eugenol. En el primer ensayo se investig6 el efecto de el
tiempo de exposici6n en la posibilidad de capture. Los machos tratados fueron ali
mentados con methyl eugenol por 30 segundos y tuvieron acceso a el methyl eugenol
por 1, 4 o 24 horas imediatamente antes de la liberation de los machos. No hubo
diferencias significativas para la capture (1-4%) entire los diferentes tratamientos,
pero hubo diferencias entire los machos que habian sido expuestos al eugenol com
paradas con los machos sin tratamiento (22%). En el segundo experiment, los ma
chos tratados por dos horas con methyl eugenol fueron liberados a los 7, 21 o 35 dias
despues de tratamiento. No hubo diferencias de capture entire tratamientos, pero la
capture fu6 menor (34%) que en el testigo. Los ensayos de laboratorio dieron result
dos simlares en cuanto a la incidencia y la duraci6n de la re-alimentaci6n con methyl
eugenol y la capture fu6 baja para los machos expuestos por 7, 21 o 35 dias.
Al exponer los machos esteriles a el atrayente antes de su liberaci6n, puede ser
possible el combinar programs de eliminaci6n de machos y de liberaci6n de machos
esteriles. Los resultados sugieren que la eficiencia de la eliminaci6n de machos puede
aumentar en aquellas areas en las cuales los machos salvajes han consumido can
tidades suficientes de methyl eugenol proveniente de fuentes naturales.




The males of several economically important tephritid species are strongly at
tracted to particular chemical compounds, termed "male lures" or "paraphero
mones", that either occur naturally in plants or are (presumed) synthetic analogues

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. O. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
TIns document was created with FrameMaker 4.0.2






Florida Entomologist 77(2)


of plant-borne substances (Chambers 1977; Sivinski & Calkins 1986; Fletcher 1987).
Several well-known examples include the attraction of male Mediterranean fruit
flies, Ceratitis capitata (Wiedemann), to trimedlure, male melon flies, Bactrocera cu-
curbitae (Coquillett), to cue-lure, and male Oriental fruit flies, B. dorsalis (Hendel),
to methyl eugenol. Owing to their powerful attractancy, parapheromones play an im
portant role in current control programs of tephritid pests, both in detecting incipi
ent population outbreaks and eradicating already established populations via male
annihilation (Chambers 1977).
Despite the wide use of male lures in control efforts, relatively little attention has
been given to explaining the underlying biological basis of this sex-specific, chemical
attraction. In a recent study on the Oriental fruit fly, Shelly & Dewire (1993) found
that "treated" males that fed on methyl eugenol achieved significantly more matings
than "control" males deprived of methyl eugenol. Interestingly, treated males had a
mating advantage even when they fed on methyl eugenol for only 30 s and were
tested 35 d post-feeding.
The present study investigates the tendency of B. dorsalis males to re-visit a me
thyl eugenol source following an initial exposure. Specifically, two field experiments
and one laboratory experiment were conducted to examine whether the duration of
the initial exposure and the time elapsed since the initial exposure affected the inci
dence and duration of re-feeding. Based on the results of mating trials (Shelly &
Dewire 1993), I predicted that neither the duration of the initial exposure (at least
for exposure periods exceeding 30 s) nor the time elapsed since the initial feeding (at
least for intervals up to 35 d) would significantly affect the tendency for re-feeding.


MATERIALS AND METHODS

Field Experiments

All flies used in field tests were from a colony maintained by the USDA/ARS Trop
ical Fruit and Vegetable Laboratory, Honolulu, for approximately 70 generations (M.
Fujimoto, pers. comm.) using standard rearing procedures (Tanaka et al. 1969). Non
irradiated pupae were obtained 2 d prior to eclosion, and adults were sexed within 5
d of eclosion [(sexual maturity in this stock is attained at about 10 d of age, (M.
Fujimoto, pers. comm.)]. Males were kept in 5-liter plastic buckets (50 per bucket)
covered with screen mesh and given food and water ad libitum.
Experiments were conducted at 2 locations on the island of Oahu, Hawaii. Dur
ing September-October, 1991, I used a 0.6-ha citrus grove in the University of Hawaii
Agricultural Experiment Station, Waimanalo, that contained approximately 60 or
ange trees (Citrus sinensis (L.)). The grove was bordered on two sides by an open field
containing small patches of guava (Psidium guajava L.) and coffee (Coffea arabica
L.) and on the other two sides by highly disturbed, second-growth forest. During
May-July, 1992, field-work was conducted at the Kanewai Garden near the campus
of the University of Hawaii, Honolulu. This small area (0.4 ha) contained six large
mango trees (Mangifera indica L.) and was bordered by an open lot on one side and
lawns containing non-host vegetation on the remaining sides.
Two field experiments were performed. At Waimanalo, I examined whether the
duration of exposure to methyl eugenol affected capture probability. As described be
low, treated males fed on methyl eugenol for only 30 s or had access to methyl eu
genol for 1 h, 4 h, or 24 h immediately prior to release. At the Kanewai Garden, I
examined the effect of time lapse following initial feeding on capture probability.
Treated males had access to methyl eugenol for 2 h and were released 7 d, 21 d, or 35
d later. An additional set of treated males was permitted to feed on methyl eugenol
for only 30 s and was released 35 d later. Control males that had no exposure to me
thyl eugenol were also released in both experiments.


June, 1994







Shelly: Methyl eugenol consumption byBactrocera dorsalis 203


To obtain treated males, 1.5 ml of methyl eugenol was applied to 5-cm long cotton
wicks, and the wicks, held upright in small plastic containers, were placed singly in
the appropriate buckets during midday. Buckets were placed on a shaded outdoor
porch where air temperatures varied between 29-31 OC (or 23-31 OC during 24 h ex
posure periods). The feeding activity of individual males was not monitored during
exposure periods of 1 h or more. To obtain males with 30 s feeding times, groups of 5
10 males were observed in screen cages (30 cm cubes with a cloth sleeve on one side)
containing a single wick. Individuals were removed after 30 s of feeding by gently
coaxing" them into a vial. In all cases, treated males were exposed to methyl eugenol
at 14 d of age and correspondingly were released at the age of 14 d at the Waimanalo
site and 21 d, 35 d, or 49 d at Kanewai Garden. At Waimanalo, control males were 14
d old at release, while at Kanewai Garden separate control groups of males aged 21
d, 35 d, and 49 d, respectively, were used for the two treatment categories. Prior to re
lease, control males and the males in the different treatment groups were cooled and
marked on the thorax with different color combinations of enamel paint (a given
combination was used only once at either field site). The cooling and painting proce
dures had no apparent adverse effects on male behavior, and individuals resumed
normal" activities within minutes of handling.
The following protocol was used for the tests conducted at Waimanalo. On the
day prior to a release, Steiner traps were placed singly in 16 different trees located
throughout the grove. The same trees were used in all tests. Traps were suspended
in the canopy by a 30-cm long wire fastened to a branch. Each trap contained a 5-cm
long cotton wick to which 1.5 ml of methyl eugenol (3% naled) had been applied. For
all tests, the males were released beneath a centrally located orange tree between
1500-1700 hours. The actual release was accomplished by removing the screen top
and gently tapping the bucket to induce flight. Males that were unable to fly were not
counted in the release sample. Traps were checked 5 d after release, and in the labo
ratory captured flies were examined individually for markings. Six replicates were
conducted with 75-112 males released per group (control or treatment) per replicate.
A similar release protocol was employed at the Kanewai Garden site. However,
owing to the small size of the garden, only eight Steiner traps were used at this site.
The traps were placed in a circle (70-m radius) around a central release point (a
mango tree). Eight replicates were conducted for tests involving treated males ex
posed to methyl eugenol for 2 h and released 7 d or 21 d later, with 122 143 males re
leased per group (control or treatment) per replicate. Four replicates were conducted
for tests involving treated males released 35 d after either exposure to methyl eu
genol for 2 h (82-113 males per group per replicate) or feeding on methyl eugenol for
only 30 s (79-120 males released per group per replicate).

Laboratory Observations

The effects of feeding duration and time since first feeding on the incidence and
duration of repeat feeding were also investigated in the laboratory. Males used in
these tests were from a laboratory stock started in November, 1991, with 200-300
adults reared from mangos collected in Waimanalo. Data were collected in July-Sep
tember, 1992; consequently, the individuals observed were approximately eight gen
erations removed from the wild. Larvae were reared on papaya, and adults were
separated by sex within 7 d of eclosion, well before reaching sexual maturity (at ap
proximately 15-20 d of age, Foote & Carey 1987).
Treated males fed on methyl eugenol for only 30 s (following the protocol de
scribed above) or had access to methyl eugenol for a 30-min period during which
their feeding activity was monitored. To obtain this latter group, five uniquely
marked individuals were placed in screen cages (30-cm cubes), allowed a 1 2 h "accli
mation period", and then given free access to a 5-cm long cotton wick to which 1.5 ml
of methyl eugenol had been applied. The amount of time that individual males fed on






Florida Entomologist 77(2)


the wick was then recorded to the nearest second. All observations were made be
tween 1100-1330 hours on a shaded outdoor porch at temperatures between 29-31
OC. Following the initial exposure, treated males were kept in 5-liter plastic buckets
and given ample food and water.
Treated males -both those restricted to 30 s feeding and those given 30 min ac
cess -were held 7 d, 21 d, or 35 d before a second exposure (30 min) during which
feeding times of individual males were recorded. All treated males were initially ex
posed to methyl eugenol at 25 d of age. To investigate the possibility that male age
was partly responsible for any feeding differences observed between the first and sec
ond exposures, I recorded the feeding times of uniquely marked, control males given
their first exposure (30 min) to methyl eugenol at ages 32 d, 46 d, and 60 d, respect
tively (ages correspond to those of treated males held 7 d, 21 d, or 35 d, respectively).

RESULTS


Field Experiments


In the Waimanalo experiment, no significant differences in capture probability
were found among males in the different treatment groups (H=6.1; P > 0.05;
Kruskal-Wallis test; Fig. 1). Among the different exposure groups, only 1%-4% of the
males were captured, on average, in a given replicate. In contrast, 22% of control


25-



20-


:15 -




15-
0a
0)

10-



5-



0-


C T-30 s


T-1 h


T-4 h


T-24 h


Release group
Fig. 1. Capture probabilities of B. dorsalis males exposed to methyl eugenol for
varying lengths of time. Points represent average proportion of males captured per
replicate; vertical lines indicate + standard error. Release groups: C control,
T=treated. T 30 s males were restricted to 30 s of feeding on methyl eugenol; the re
maining groups of treated males had access to methyl eugenol for 1 h, 4 h, or 24 h, re
spectively. See text for sample sizes.


III


June, 1994






Shelly: Methyl eugenol consumption byBactrocera dorsalis 205


males were captured, on average, in a given replicate. The capture probability of con
trol males differed significantly from males exposed for 1 h (q=5.6), 4 h (q=6.0), or 24
h (q=5.2) as well as from males whose feeding was restricted to 30 s (q=7.9; P < 0.005
in all cases; multiple comparisons test, Zar 1974: 156).
At the Kanewai Garden, no significant differences in capture probability were
detected among males exposed to methyl eugenol for 2 h but released after differing
time intervals (H=5.1; P > 0.05; Kruskal-Wallis test; Fig. 2). Over the different inter
vals, only 11%-18% of the treated males were captured, on average, in a given repli
cate. Similarly, capture probabilities did not differ among control males held for
varying periods before release (H=0.5; P > 0.05; Kruskal-Wallis test; Fig. 2). On av
erage, approximately 33% of control males were trapped over all pre-release inter
vals. Based on data pooled over all pre-release intervals, the capture probability for
control males was significantly higher than that observed for males given 2 h access
to methyl eugenol before release (U=387.5; P < 0.001; Mann-Whitney test). Treated
males that fed for only 30 s prior to their release 35 d later also had low capture prob
ability (Fig. 2). An average of 11% of these males was captured per replicate, the
same proportion observed for males released 35 d after 2 h exposure to methyl eu
genol (U=9; P > 0.05; Mann-Whitney test).

Laboratory Observations

Among treated males given an initial 30-min exposure period, feeding durations
were significantly shorter during the second exposure for males tested 7 d (T=276;
n=54), 21 d (T 87; n 53), or 35 d (T 3; n 27) after the initial feeding (P < 0.001 in all



50-



40-



0-.30-
o A Control

a* Treated-2 h
*jU 201








0 10 20 30 40
Days since exposure
Fig. 2. Capture probabilities of B. dorsalis males held varying lengths of time af
ter exposure to methyl eugenol. Points represent average proportion of males cap
tured per replicate; vertical lines indicate + standard error. One set of treated males
(held 35 d) was restricted to 30 s of feeding on methyl eugenol; all other treated males
had access to methyl eugenol for 2 h. See text for sample sizes.






206 Florida Entomologist 77(2) June, 1994


cases; Wilcox on paired-sample test; Fig. 3). Moreover, for these males, feeding dura
tions during the second exposure were independent of time elapsed since the initial
feeding (H=l.1; P > 0.05; Kruskal-Wallis test). Among the different trials, 85%-91%
of the males consumed methyl eugenol during the initial exposure compared to only
32%-38% during the second exposure. Decreased feeding during the second exposure
was apparently not age-related: average feeding durations were similar among con
trol males aged 32 d (n=35), 46 d (n=40), and 60 d (n=40; H=3.9; P > 0.05; Kruskal
Wallis test; Fig. 3). Data pooled over the different inter-exposure intervals (or, equiv
alently, male ages) revealed that, during their second exposure period, treated males
fed for shorter periods of time, on average, than control males (Z=11.1; P < 0.05;
nl=134, n2=115; Mann-Whitney U-test).
Among treated males given an initial 30-min exposure, there was no correlation
in the feeding times of individual males between the first and second exposure peri
ods (rs=0.05; P > 0.05; n=134; Spearman rank). Even if only the incidence of feeding
is considered (i.e., regardless of duration), feeding activity during the first exposure
period was still not a reliable predictor of subsequent feeding activity: males that fed
during the first exposure period were as likely to feed during the second period (48 of
118=41%) as were males that did not feed at all during the initial exposure (8 of
16=50%; G=0.4; P > 0.05; G test with Yates correction). Among treated males given
two 30-min exposure periods, 6% (8/134) did not feed on methyl eugenol during ei
their period.



7-


6-


5-

S41
0 4T Treated-30 min

-o A Control



I I f




0
0 10 20 30 40
Days since initial exposure
Fig. 3. Feeding times of B. dorsalis males during their second exposure to methyl
eugenol 7 d, 21 d, or 35 d after the initial exposure. One set of treated males was given
an initial 30 min exposure period, while another set was restricted to an initial feed
ing of 30 s; for both sets of treated males, the second exposure period was 30 min.
Data for control males represent feeding durations during initial 30-min exposure pe
riods at ages corresponding to males in different treatment groups. Points represent
average values; vertical lines indicate + standard error. The value plotted for the ini
tial exposure was calculated over all treated males given an initial 30-min exposure
period. See text for sample sizes.







Shelly: Methyl eugenol consumption byBactrocera dorsalis 207


Treated males limited to an initial feeding of 30 s also displayed low feeding ac
tivity during the second exposure period (Fig. 3). In fact, when re-exposed to methyl
eugenol 7 d (n=35 males) or 21 d (n=35 males) after the first feeding, these individu
als had feeding durations that were similar to (and not greater than, as might be ex
pected) males given an initial access of 30 min (7 d Z0.6; n=135, n2=54; 21 d
Z=0.5; n=135, n2=53; P > 0.05 in both cases; Mann-Whitney U-test). However, at 35
d after the initial exposure, males (n=40) limited initially to a 30 s feeding fed longer,
on average, than males first given a 30 min exposure period (Z=2.7; P < 0.01; n=140,
n2=27; Mann-Whitney U-test). Though feeding durations of these males increased
after 35 d, they were still significantly lower than those of control males of the same
age (Z 2.1; P < 0.05; n=1n2 40; Mann-Whitney U-test).


DISCUSSION

Results of the present study indicate that after an initial exposure, B. dorsalis
males have a greatly reduced tendency to re-visit a methyl eugenol source. In the
field experiments, males that were permitted only 30 s feeding on methyl eugenol
were rarely captured in methyl eugenol-baited traps even when released 35 d after
feeding. Similarly, in the laboratory most males given an initial exposure of 30 min
"ignored" a methyl eugenol source placed directly in their cage 35 d later.
Though data are scant, it appears that a dramatic reduction in male respon
siveness to lures following exposure characterizes other tephritid species as well. Us
ing a large outdoor cage, Chambers et al. (1972) reported that, after initial exposure
to cue-lure, only 14% of male B. cucurbitae, on average, responded to cue-lure-baited
traps compared to 50% of control (unexposed) males. Similarly, Brieze-Stegeman et
al. (1978) placed dye in a methyl eugenol-baited trap (lacking poison) and found that
only 13% (daily average) of the B. cacuminatus (Hering) males seen at the trap over
the next several days were marked.
The major difficulty in interpreting laboratory studies on male attraction to
lures is the scarcity of field data regarding both the availability of parapheromones
in natural sources and the feeding behavior of males at these sources. To my knowl
edge, no data exist regarding either the incidence and duration of feeding bouts or
the rate and amount of parapheromone consumption during these bouts. It is likely
that the 1-2 ml doses of parapheromones used by experimenters (Chambers et al.
1972; Brieze-Stegeman et al. 1978; present study) exceed levels available in natural
sources (e.g., Kawano et al. 1968). Despite this possible discrepancy, it is certainly
conceivable that in the wild, males initially make frequent or prolonged feeding
bouts and in so doing eventually consume parapheromone in amounts similar to
males observed in laboratory studies. In other words, though the feeding time re
quired to inhibit subsequent feeding is reduced in laboratory studies, the basic pat
tern of decreased responsiveness to parapheromones may nonetheless be
characteristic of wild males.
The present study has three major implications for control or eradication
projects of tephritid pests. First, by exposing sterile males to the lure prior to their
release, workers may be able to combine programs of male annihilation and sterile
insect release. As noted by Chambers et al. (1972), pre-exposure of sterile males may
increase the efficiency of achieving effective overflooding ratios, since wild males
would respond to lure-baited traps, whereas sterile males would not. Pre-exposure to
the parapheromone may also increase the mating competitiveness of sterile males
(Shelly & Dewire 1993), further enhancing the effectiveness of the sterile insect re
lease method. Second, the present findings suggest the possibility that wild males
that have consumed sufficient amounts of parapheromone from natural sources may
show reduced attraction to lure-baited traps, thus potentially reducing the effective
ness of male annihilation programs. Finally, and somewhat unexpectedly, 6% of the







Florida Entomologist 77(2)


males observed in the laboratory tests were not attracted to methyl eugenol in two
separate exposure periods. The possibility that some males in a population may re
spond only slightly or not at all to parapheromones implies that in certain situations
male annihilation may fail to achieve total eradication. Studies in our laboratory are
currently investigating the genetic basis of male responsiveness to parapheromones
using the B. dorsalis methyl eugenol association.


ACKNOWLEDGMENTS

I thank the staff of the University of Hawaii Agricultural Experiment Station in
Waimanalo for their cooperation. Annie Dewire, Stacey Fong, Caryn Ihori, Cheryl
Monez, and Michael Whang provided capable laboratory assistance, and to all I am
grateful. Also, I thank Emma Shelly who, despite her young age, was a great help in
counting marked flies in trap catches. Comments by Tim Whittier greatly improved
the paper. This research was supported by funds from the California Department of
Food and Agriculture (90-0581) and the USDA/ARS (58-91H2-6-42).


REFERENCES CITED

BRIEZE-STEGEMAN, R., M. J. RICE, AND G. H. S. HOOPER. 1978. Daily periodicity in
attraction of male tephritid fruit flies to synthetic chemical lures. J. Austra
lian Entomol. Soc. 17: 341-346.
CHAMBERS, D. L., K. OHINATA, M. FUJIMOTO, AND S. KASHIWAI. 1972. Treating te
phritids with attractants to enhance their effectiveness in sterile-release pro
grams. J. Econ. Entomol. 65: 279-282.
CHAMBERS, D. L. 1977. Attractants for fruit fly survey and control, pp. 327-344 in H.
H. Shorey and J. J. McKelvey [eds.], Chemical control of insect behavior.
Wiley, New York.
FLETCHER, B. S. 1987. The biology of dacine fruit flies. Ann. Rev. Entomol. 32: 115
144.
FOOTE, D., AND J. R. CAREY. 1987. Comparative demography of a laboratory and a
wild strain of the Oriental fruit fly, Dacus dorsalis. Entomol. Exp. Appl. 44:
263-268.
KAWANO, Y., W. C. MITCHELL, AND H. MATSUMOTO. 1968. Identification of the male
Oriental fruit fly attractant in the golden shower blossom. J. Econ. Entomol.
61: 986-988.
SHELLY, T. E., AND A. DEWIRE. 1993. Chemically mediated mating success in male
Oriental fruit flies, Bactrocera dorsalis (Diptera: Tephritidae). Ann. Entomol.
Soc. America. In press.
SIVINSKI, J. M., AND C. CALKINS. 1986. Pheromones and parapheromones in the con
trol of tephritids. Florida Entomol. 69: 157-168.
TANAKA, N., L. F STEINER, K. OHINATA, AND R. OKAMOTO. 1969. Low-cost larval
rearing medium for mass production of Oriental and Mediterranean fruit flies.
J. Econ. Entomol. 62: 967-968.
Zar, J. H. 1974. Biostatistical analysis. Prentice-Hall, Inc. Englewood Cliffs, NJ.


June, 1994







Fontes et al.: Phytophagous Insects Associated with Goldenrods209


PHYTOPHAGOUS INSECTS ASSOCIATED WITH
GOLDENRODS (SOLIDAGOSPP.) IN GAINESVILLE, FLORIDA


E. M. G. FONTES1, D. H. HABECK, AND F. SLANSKY, JR.
Dept. of Entomology & Nematology
University of Florida
Gainesville, FL 32611-0740


ABSTRACT

The insect fauna of four species of goldenrods, Solidago canadensis var. scabra, S.
fistulosa, S. gigantea and S. leavenworthii, was surveyed during four years in and
around Gainesville, Florida. The 122 phytophagous species collected are listed and
classified according to relative frequency of occurrence, guild, host range, plant part
attacked, life stages collected, and associated goldenrod species. Only 14 (11%) of the
phytophagous species are known to be restricted to goldenrods and Aster (Composi
tae). Eight insect species are considered as possible biological control agents of Sol
idago spp.

RESUME

La fauna de insects present en cuatro species de vara de oro, Solidago ca
nadensis var scabra, S. fistulosa, S. gigantea y S. leavenworthii fue, estudiada en
Gainesville, Florida durante cuatro anos. Los 122 specimenes fitdfagos colectados, se
han listado y clasificado de acuerdo a la frequencia relative de aparicidn, asociacidn,
rango de hospedantes, parte de la plant atacada, estado de desarrollo y species de
vara de oro a las que se asociaron. Solamente 14 (11%) de los fit6fagos hallados son
conocidos como especificos de las vara de oro y Aster (Compositae). Ocho species son
consideradas como posibles agents de control biol6gico de Solidago spp.



Goldenrods (Asteraceae: Solidago spp.) are common on roadsides and in open
fields throughout the eastern United States. They first attracted the attention of nat
uralists because of their aesthetic appeal and as a nectar source for pollinators in
late fall (Feller-Demalsy & Lamontagne 1979, Hensel 1982). Goldenrods have been
studied as sources of natural enemies of field crop pests in a mixed crop system (Alt
ieri 1979) and as competitors with seedlings of woody trees (Norbi & Kozlowski
1980). They can also serve as a reservoir for disease-producing organisms that attack
plants of economic importance (Werner et al. 1980). Introduced to Europe and Japan
about 1900, goldenrods have become aggressive pests of forest nurseries and refores
station areas (Capek 1971). The high cost and low efficiency of chemical and mechan
ical control of these weeds have resulted in interest in a biological control program in
Russia (0. Kovalev, pers. comm.).
Basic information on the arthropod community structure of goldenrods is rele
vant if goldenrod populations are to be manipulated either as beneficial plants that
should be maintained or even enhanced, or as undesirable plants that should be con
trolled. This paper lists the phytophagous insect fauna of four species of goldenrods,
(Solidago canadensis L. var. scabra (Muhl) [treated by many as S. altissima L.], S.
fistulosa Miller, S. gigantea Aiton, and S. leavenworthiiTorr. & Gray), in and around
Gainesville, Florida. It also gives information on the relative abundance of the differ
ent taxa, parts of the plant attacked, and specificity of the phytophagous insects.


'Present address: EMBRAPA, CENARGEN, S.A.I.N. Parque Rural, C.P. 10.2372 Brasilia DF CEP 70.770,
BRAZIL.

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. 0. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
-------- Ti -- do n... I .. as cn1 l vv.-. .iai'Mk'i -- .02 ---







Florida Entomologist 77(2)


MATERIAL AND METHODS

The insect fauna of goldenrods was surveyed for four consecutive growing sea
sons. Surveys began in June 1981 and were made on goldenrod populations as they
occurred naturally. Plants, including roots, were checked in the field and/or placed in
plastic bags and returned to the laboratory for examination. Insect-damaged plant
parts were carefully examined under the microscope. Immature insects were reared
individually, with information recorded as to the life stage collected, part of the plant
damaged, life history, appearance, emergence of adults or parasites, presence of dis
ease, and other relevant information. Flying insects were captured by making 10
sweeps with a sweep net while walking in a straight line through the goldenrod
patch. Adults were preserved in alcohol and identified. Plants were sampled at dif
ferent times of the year and at various growth stages ..l II i flowering and ma
ture). In 1982, 16 populations of the four plant species were selected of which two
were surveyed each week following the same procedure. Of the four goldenrod spe
cies, S. canadensis var. scabra was the most common (11 of the 16 populations) and
occurred on ditch banks, roadsides, and clearings in woody areas. The second most
common species, S. fistulosa, occurred in old abandoned fields forming large stands
sometimes mixed with blackberries. The single stand of S. gigantea was small and
located on a poorly drained roadside. The S. leavenworthii stand was mixed with
many other weeds and was growing on a small ditch bank in a very disturbed area.
Growth of all four species started in March; S. leavenworthii and S. gigantea flow
ered in late August, S. fistulosa in mid-September and S. canadensis var. scabra in
late September. The goldenrod stems were completely dead by the beginning of De
cember. In 1983, three populations of S. canadensis, two of S. fistulosa, and single
populations of S. gigantea and S. leavenworthii, were selected for in-depth study. The
dynamics of the insect fauna in relation to host plant phenology was followed by sur
veying these seven populations during four periods of the growing season: early
(May), middle (July), about 10 days before blooming (August or early September),
and shortly after blooming (late September or early October). Collections in 1984
were made only on S. canadensis var. scabra and S. leavenworthii.
A phytophagous species was considered common if it was present in at least 50%
of the collections, occasional if collected in 15 to 50% of the samples, and rare if
present in less than 15% of the samples. Insects collected only once during the four
years were excluded, as were those collected often but known to be nectar/pollen
feeders or incidental and associated with other plants.


RESULTS AND DISCUSSION

Seven orders, encompassing 41 families with 123 species of phytophagous insects
(other than nectar/pollen feeders) were found associated with Solidago spp. (Table
1). Of these, 60 species (49.2%) bred on these plants, as indicated by the presence of
immature stages. The cercopid Lepyronia quadrangularis (Say), the cicadellid Os
bornellus clarus Beamer, and the delphacid Pissonotus marginatus Van Duzee were
new Alachua County records, and the gracillariid Cremastobombycia solidaginis
(Frey and Boll.) was a new state record.
Of the phytophagous insect species, 16 (13.1%) fed only on Solidago or on Sol
idago and Aster, seven (5.7%) fed on these plants as well as other Compositae, 94
(77%) were polyphagous and 5 (4.1%) had unknown hosts. Sucking insects comprised
the majority of the phytophagous insects with 35 species of Homoptera and 25 spe
cies of Hemiptera collected from leaves, stems and flowers. There were 14 species of
cicadellids, six of which were common. The pentatomids and mirids were repre
sented by six species each, and the lygaeids by five.


June, 1994







Fontes et al.: Phytophagous Insects Associated with Goldenrods211


TABLE 1. PHYTOPHAGOUS INSECT FAUNA OF SOLIDAGO SPP. IN THE VICINITY OF
GAINESVILLE, FL


Relative Stages Plant Solidago Host
Freq.1 Coll.2 Part(s)3 Guild4 spp. Spec.6


DIPTERA

Agromyzidae
Agromyzidae sp. 1
Agromyzidae sp. 2


C L,PA L
C LPA L


Cecidomyiidae
Asphondylia monacha C L,PA L
Osten Sacken
Asteromyia carbonifera C L,PA L
(Osten Sacken)
Asteromyia sp. nr.
carbonifera
(Osten Sacken) C L L
Dasyneura sp. C L L
Rhopalomyia sp.
(prob. new) O L,PA St
Rhopalomyia
solidaginis (Loew) O L,PA St
Schizomyia racemicola
(Osten Sacken) 0 L,A F


G c,f,g,l M


c,f,g,l M
c,f,g,l M


G f M

G f,g,l M

G c,f M


Tephritidae
Eurosta prob. comma
(Wied.)


COLEOPTERA


Cerambycidae
Strangalia sexnotata
Hald

Chrysomelidae
Arthrochlamys plicatus
(Fab.)
Colaspis brunnea
(Fab.)
Colaspis favosa (Say)
Diabrotica
undecimpunctata
howardi Barber
Diachus auratus Fab.
Exema canadensis
Pierce


R A


R L

R A
R A


R A
O A


F C f


L C cf P


C L,PA L C c,f,l P


M c,f,g,l
M c,f,g,l


R L


R G







Florida Entomologist 77(2)


TABLE 1. (CONTINUED) PHYTOPHAGOUS INSECT FAUNA OF SOLIDAGO SPP. IN THE
VICINITY OF GAINESVILLE, FL

Relative Stages Plant Solidago Host
Freq.1 Coll.2 Part(s)3 Guild4 spp. Spec.6


Exema sp.
Ophraella sexvittata
(LeC.)
Paria sp. nr. aterrima
(Oliver)
Rhabdopterus sp.
Systena elongata (Fab.)


Curculionidae
Centrinaspis
picumnus (Herbst)
Epicaerus formidolosus
Boheman
Limnobaris sp.
Notolomus basalis
LeC.
Pachnaeus opalus
(Oliver)
Tanymecus "lacaena
(Hbst.)" complex


Elateridae
Conoderus lividus
(De Geer)
Glyphonyxsp.


Meloidae
Epicauta sp.


Mordellidae
Mordellistena sp.


Phalacridae
Olibrus sp.


Scarabaeidae
Trigonopeltastes delta
(Forst.)


HEMIPTERA

Alydidae
Alydus pilosulus
(Herrich-Shaffer)


R L


L C c,l F


C E,L,A L C c,f,g,l M


O A
R A
R A


C A

R A
O A

C A

R A

O A


R A
R A



O A



R A



R A




O A


L,F C c,f,l P


F C c,f,g

L C c

L,F C c


F C c,f P



L C c,l



L C c,f




F C c,f,l P


L S c,g,l P


June, 1994


0 A







Fontes et al.: Phytophagous Insects Associated with Goldenrods213


TABLE 1. (CONTINUED) PHYTOPHAGOUS INSECT FAUNA OF SOLIDAGO SPP. IN THE
VICINITY OF GAINESVILLE, FL

Relative Stages Plant Solidafo Host
Freq.1 Coll.2 Part(s)3 Guild4 spp. Spec.6


Leptocorisa filiformis
(Fab.)


Coreidae
Acanthocephala
femorata (Fab.)
Leptoglossus phyllopus
(L.)


Lygaeidae
Cymonimus notabilis
(Distant)
Ochrostomus
lineoloides Slater
Ocrimnus mimulus
(Stal)
Oedancala crassimana
(Fab.)
Pachybrachius
bilotatus (Say)


Miridae
Adelphocoris rapids
(Say)


R L,A F S


O E,L,A L S c,f,l P


C A


R A

R A


L S c,f,g,l P


L S c,f P

F,L S f,l P


C L,A L,S S c,f,l

R L,A L S f

C L,A FL S c,g,l


0 A


Lepidopsallus pusillus
(Knight) O A
Lygus lineolaris
(Palisot de Beauvois) C A
Polymerus punctipes
Knight R A
Rhinacloa pusillia
(Knight) R A
Taylorilygus pallidulus
(Blanchard) C L,A


Pentatomidae
Euschistus obscurus
(Palisot de Beauvois) R A
Euschistus servus (Say) C L,A
Holcostethus
limbolarius (Stal) R A
Nezara viridula (L.) C E,L,A
Oebalus pugnax (F.) R L,A
Thyanta custator (F.) C L,A


L S c,f,l P

L S c,f,l P

L S f,g,l P


L S f


F S c,l P

L S c,f,g,l P







Florida Entomologist 77(2)


TABLE 1. (CONTINUED) PHYTOPHAGOUS INSECT FAUNA OF SOLIDAGO SPP. IN THE
VICINITY OF GAINESVILLE, FL

Relative Stages Plant Solidago Host
Freq.1 Coll.2 Part(s)3 Guild4 spp. Spec.6


Tingidae
Corythucha
marmorata (Uhler)


Rhopalidae
Arhyssus lateralis
(Say)
Arhyssus nigristernum
(Signoret)
Harmostes reflexulus
(Say)


C E,L,A L S cf A


R A

0 A

R A


F S c,f

F S g,l P

F S c,f P


HOMOPTERA


Aphididae
Aphis sp.
Hyperomyzus lactucae
(L.)
Uroleucon ambrosiae
(C. Thomas)
Uroleucon gravicornis
(Patch)


Cercopidae
Clastoptera
xanthocephala
German
Lepyronia
quadrangularis
(Say)


Cicadellidae
Agallia constricta
Van Duzee
Chlorotettix viridius
Van Duzee
Empoasca sp.
Exitianus exitiosus
(Uhler)
Graminella sonorus
(Ball)
Graphocephala
versuta (Say)
Gyponana sp.


O L,A L S c,f P

C L,A St S c,f,l P

C L,A St S c,f,g,l P

C L,A St S c,f,g,l P





C L,A St S c,f,g,l P


C LA St S c,f,l P


R A

R A
C L,A

R A

R A

C A
C L,A


L S g,f P


f P
c,f,g,l P


L S 1

F S 1


c,f,g,l P
c,f,g,l P


June, 1994







Fontes et al.: Phytophagous Insects Associated with Goldenrods215


TABLE 1. (CONTINUED) PHYTOPHAGOUS INSECT FAUNA OF SOLIDAGO SPP. IN THE
VICINITY OF GAINESVILLE, FL

Relative Stages Plant Solidafo Host
Freq.1 Coll.2 Part(s)3 Guild4 spp. Spec.6


Homalodisca coagulata
(Say)


C A


Homalodisca insolita
(Walker) R A
Oncometopia nigricans
(Walker) C E,L,A
Osbornellus clarus
Beamer O A
Scaphytopius sp. nr.
acutus (Say) C L,A
Scaphytopius sp. prob.
frontalis (Van Duzee) O A
Sibovia occatoria (Say) R A


L S c,f,g,l P


L S

L S


c,f,g,l P


L S c,f,g

L S c,f,g


Coccidae
Coccus hesperidum L.


R A


L S g P


Delphacidae
Pissonotus marginatus
Van Duzee R A
Sogatella kolophon
meridiana (Beamer) R A
Diaspididae
Abgrallaspis
cyanophylli
(Signoret) R A
Aonidomytilus
solidaginis (Hoke) O L,A
Hemiberlesia lataniae
(Signoret) R A
Pseudaulacaspis
pentagon
(Targ. Tozz.) R A


L S c,f P


L S


L S f


St S c,f A


St S f


L S f


Dictyopharidae
Rhynchomitra sp.


Flatidae
Ormenoides venusta
(Melichar)


C L,A L S c,f,g


R A


Membracidae
Acutalis tartarea (Say) C L,A
Entylia bactriana
Germar 0 L,A


L S


St S c,f,g,l P

St S cf P







Florida Entomologist 77(2)


TABLE 1. (CONTINUED) PHYTOPHAGOUS INSECT FAUNA OF SOLIDAGO SPP. IN THE
VICINITY OF GAINESVILLE, FL

Relative Stages Plant Solidago Host
Freq.1 Coll.2 Part(s)3 Guild4 spp. Spec.6
Micrutalis calva (Say) C A L S c,f,g,l P
Spissistilus festinus
(Say) O A L S c,f P

Psyllidae


Aphalara sp.
Craspedolepta veaziei
(Patch)

LEPIDOPTERA


Gelechiidae
Gnorimoschema
gallaesolidaginis
(Riley)
Trichotaphe
flavocostella (Clem.)
Trichotaphe inserrata
(Wlsm.)

Geometridae
Eupithecia miserulata
Grote
Pleuroprucha
insulsaria (Guenee)
Synchlora frondaria
(Walk.)


Gracillariidae
Cremastobombycia
solidaginis
(Frey and Boll.)


Lyonetiidae
Bucculatrix
solidaginiella Braun


Noctuidae
Schinia nundina
(Drury)


Pterophoridae
Oidaematophorus
kellicottii (Fish)


O L,A St S f,l P


O A


L S f,g


O L,PA St

C L,PA L

C L.PA St


0 L,PA F


G f,g M

L cf A


B c


C c,f P


R L,A F C f,g P

O L,PA L,F C c,f,l P


C L,PA L


R P.A


M c,f,g


L M


R L,PA FSd


C f


C L,A St B c,f,g,l A


June, 1994







Fontes et al.: Phytophagous Insects Associated with Goldenrods217


TABLE 1. (CONTINUED) PHYTOPHAGOUS INSECT FAUNA OF SOLIDAGO SPP. IN THE
VICINITY OF GAINESVILLE, FL

Relative Stages Plant Solidafo Host
Freq.1 Coll.2 Part(s)3 Guild4 spp. Spec.6


Tortricidae
Platynota flavedana
Clem.
Platynota rostrana
(Walk.)
Sparganothis distinct
(Walsing.)


R L L C

R L,P F C


C L,PA L L c,f,g,l M


ORTHOPTERA


Acrididae
Aptenopedes
sphenarioides
Scudder
Melanoplus sp.
Paroxya atlantica
Scudder
Schistocerca damnifica
(Saussure)


Blatellidae
Cariblatta lutea
(Saussure Zehntner)


Grylliidae
Hapithus brevipennis
(Saussure)
Oecanthus celerinictus
Walker
Orocharis luteolira
Walker


Tettigoniidae
Amblycorypha prob.
floridana
Rehn Hebard
Belocephalus
subapterus Scudder
Odontoxiphidium
apterum Morse
Scudderia sp.


c,f,g P
c,f,g,l P


C L,A L C f,g,l P

R A L C f P


O L,A


L C


C L,A L C c,f,g,l P

0 L,A L C c,f P


R A L C


R L,A L C


0 L L C c,g P


THYSANOPTERA







Florida Entomologist 77(2)


TABLE 1. (CONTINUED) PHYTOPHAGOUS INSECT FAUNA OF SOLIDAGO SPP. IN THE
VICINITY OF GAINESVILLE, FL

Relative Stages Plant Solidago Host
Freq.1 Coll.2 Part(s)3 Guild4 spp. Spec.6
Phlaeothripidae
Elaphrothrips sp. R A L S 1


Thripidae
Microcephalothrips
abdominalis
(Crawford) R A L S 1 A
Thrips tabaci
Lindeman R A L S c P

C common; O occasional; R rare.
2E = eggs; L = larvae; P = pupa; A= adult.
3L = leaves; St = stem; F = flowers; R = roots; Sd = seeds.
4C chewing; G gallmaker; M miner; B =borer; S sucking; L leaftier.
c = Solidago canadensis var. scabra; f= S fistulosa; g = S. gigantea; 1 = S. leavenworthii.
6M = monophagous: feed only on Solidago and Aster, A= feed on Solidago and on other genera of Asteraceae;
P = Polyphagous: feed also on families other than Asteraceae.

Two mirids and three pentatomids are associated with economic damage to culti
vated plants. Lygus lineolaris Palisot de Beauvois, the tarnished plant bug, causes
serious damage by feeding on the tender growing or fruiting parts of a variety of wild
and cultivated plants (Borror et al. 1976, Metcalf & Flint 1951). Adults of this insect
were collected from May to October on S. fistulosa, S. gigantea, and S. canadensis
var. scabra. T.. .,' -..: pallidulus (Blanchard) attacks a variety of wild plants and,
when abundant, can be a pest of ornamentals (F. W. Mead, pers. comm.). It fed and
bred on all four species of goldenrod and was very common throughout the growing
season. Among the pentatomids, the southern green stink bug, Nezara viridula (L.),
is the most important because it is a pest of soybeans and other crops (Todd & Herzog
1980). It fed and bred from May to July on three of the four species of goldenrod. Eu
schistus servus (Say) and Oebalus pugnax (Fab.) also can cause damage to many
crops.
Most of the chewing insects were polyphagous. Of 12 species of chrysomelids, ap
parently only Ophraella sexvittata (LeConte) was restricted to Solidago, although
LeSage (1986) reported adults were reared from larvae on march elder, Iva frutescens
L. sp. oraria (Bart.) R. C. Jackson (Asteraceae). Systena elongata (Fab.) was rare and
collected only on S. canadensis var. scabra and S. leavenworthii. It feeds only on
plants in the Asteraceae. Diabrotica undecimpunctata howardi Barber, the spotted
cucumber beetle, was the only economic species of chrysomelid collected on Solidago.
Adults were collected several times on S. canadensis var. scabra and S. fistulosa.
Polyphagous Lepidoptera collected were restricted to three geometrid and two tortri
cid species. All species of Orthoptera collected were polyphagous. The most abundant
insect feeding only on Solidago and other Asteraceae was the tingid Corythucha mar
morata (Uhler). Its' eggs, nymphs and adults were found on S. canadensis var scabra
and S. fistulosa throughout the growing season. The pterophorid Oidaematophorus
kellicottii (Fish) was common on all four species. This moth laid its' eggs on the grow
ing tip of young goldenrod plants. The new larvae bored downward into the soft stem.
Before reaching the apparent third instar, it left the upper part of the plant stem
through a lateral hole and moved down to the mature, wider stem. Here it made an
other hole, about 10 cm above the ground, and bored downward toward the roots. Pu
pation occurred inside the stem near this entrance hole, through which the adult
emerged later. The part of the plant above where the young larva bored, wilted and


June, 1994






Fontes et al.: Phytophagous Insects Associated with Goldenrods219


died. Infested plants could be recognized by the dried tips. Young larvae were col
elected in May and mature ones were found as late as October.
Other common insects were the gelechiids Trichotaphe flavocostella (Clem.) and
T inserrata (Wlsm.). These species caused considerable damage to goldenrods; the
former as a leaftier and the latter as a borer inside the growing tip, a behavior that
interrupted the terminal growth of the plant. Most of the species restricted to Sol
idago were endophagous: eight Diptera and one Lepidoptera made galls on leaves,
flowers, stem or roots, and one Diptera and one Lepidoptera were leaf miners. The
others were Schinia nundina (Drury), a flower and seed feeder, Craspedolepta yea
ziei (Patch), a sapsucker, Sparganothis distinct (Walsingham), a leaftier and
Ophraella sexvittata (LeC.), a leaf chewer,. Biological information on the latter two
insects can be found in Fontes (1985). The others are discussed below.
The black or white leaf blister galls of Asteromyia carbonifera (Osten Sacken)
were found frequently on the four goldenrod species during this study. The number of
galls per leaf varied from one to many and sometimes covered the entire leaf. The re
lationship between A. carbonifera and the fungus that inhabits its gall was discussed
by Batra (1964). The galls were caused by both fungus and insect activity. Asteromyia
carbonifera associates with leaves of goldenrod already infected by the fungus Scle
rotium asteris (Schw.). Two or three midge larvae developed between layers of the fun
gus which forms a stroma on either side of the larval chamber. Weis (1982) showed
that the formation of this stroma is an important mechanism for protection from the
parasite Torymus capite (Huber). Also, the gall midge larvae were frequently parasit
ized by Tetrastichus sp. 1, T homeri (Girault), and T tesserus Burks, (Eulophidae).
Another leaf blister gall found occasionally on leaves of goldenrod was caused by
a midge identified as Asteromyia sp. nr. carbonifera (Osten Sacken). The circular
galls are greenish, often surrounded by a purplish necrotic area. The midges were
heavily parasitized by a eupelmid, probably Anastatus sp. Asphondylia monacha Os
ten Sacken made galls in developing buds. It established itself between the surface of
the leaves while they were still in the bud and caused the adjacent tissues to form an
oval cell between the two surfaces. The leaves continued their normal development
but attached to each other where the gall developed. A common parasite of this spe
cies was Galeopsomyia haemon (Walker) (Eulophidae). Similar damage was caused
by a midge (Dasyneura sp.) on the four goldenrod species, although the only injury
observed was to the developing, opposed leaves of the growing bud. No adults were
reared from the reddish larvae, so the species could not be determined. Another gall
midge, Rhopalomyia solidaginis (Loew) attacked buds, transforming them into glob
ular masses of deformed leaflets. In the center of the mass, a cylindrical chamber
with tapered apex sheltered the yellowish larva. This gall was seen occasionally on
all goldenrod species except S. canadensis var. scabra. It was also parasitized by G.
haemon. Rhopalomyia new sp. was collected occasionally on S. fistulosa. The larvae
developed inside individual globular galls with a tapered apex. These galls developed
together forming an agglomeration on the stem. The parasitic wasp Torymus sp. nr.
duplicatus (Hiibner), probably a new species, was reared several times from this gall.
The only flower gall observed in this study was made by the midge Schizomyia ra
cemicola (Osten Sacken). It produced a rounded gall with tapered apex (frequently
reddish) on the racemes of S. canadensis var. scabra and S. fistulosa. The larvae
were orange-red and left the gall when disturbed. Gagne (1989) provides keys and
descriptions for most of the cecidomyiids on Solidago in North America. The conspic
uous galls of Gnorimoschema gallaesolidaginis (Riley) were occasionally seen on the
stems of S. fistulosa and S. gigantea. A complete description of the biology of this in
sect is given by Leiby (1922). It is widely distributed and has also been reported from
S. canadensis var. scarbra, S. nemoralis Aiton, and S. serotina Retz. Fully grown
galls were found from July through the winter in Gainesville. In North Carolina, this
insect hibernates in the egg stage (Leiby 1922), but in Florida it apparently overwin







Florida Entomologist 77(2)


ters as a pupa inside the gall. Two adults emerged from screened galls in February,
just when goldenrod seeds were sprouting.
The rarest gall collected was made on the roots by Eurosta prob. comma (Wied.).
A large white maggot developed inside an elliptical, potato-like gall on the rhizomes
of S. fistulosa. No adults of this species were obtained. The leaf mines of the gracilla
riid moth, Cremastobombycia solidaginis, were very common on the underside of
leaves of S. canadensis var. scabra, S. fistulosa and S. gigantea. They were found
from early May to early October. The tiny larva made an irregular, roundish blotched
mine, usually centered on the underside of the leaves. As the larva grew the mine be
came elongate. By pupation, the leaf was folded in the damaged region and the mine
became wrinkled. The elongate, white cocoon in which the larva pupated was sus
pended inside the fold by silken threads. This is a common species in the United
States (Braun 1908).
Bucculatrix solidaginiella Braun is a lyonetiid moth whose larvae feed in the
growing tips or mine the leaves of various species of Solidago (Braun 1963). Only pu
pae and adults of this species were collected from the leaves of S. canadensis var sca
bra. The brightly colored yellowish larvae of the noctuid Schinia nundina were well
concealed in the flower heads of S. fistulosa, where they fed on the developing seeds.
Adults of this species occur from late July to late September in central and eastern
U.S. (Forbes 1948). No adults were collected and the larvae were observed in October
and early November. The jumping plant-louse, or psyllid, Craspedolepta veaziei has
been reported from Solidago sp. (Caldwell 1938) and Aster (Crawford 1914). Adults
were occasionally collected on leaves of S. fistulosa and S. gigantea from July to No
member.
Eight of the species recorded as feeding only on Solidago and Aster could be con
sidered for introduction into Europe or Japan for the biological control of goldenrods:
one attacks roots, Eurosta prob. comma; two are leaf chewers, Ophraella sexvittata
and Sparganothis distinct; two are leaf miners, Agromyzidae sp. 1 and Cremasto
bombycia solidaginis; one is a leafgaller, Asteromyia carbonifera; and two attack
flowers and seeds, Schizomyia racemicola and Schinia nundina. Before release,
these insects would have to be tested to make certain that they do not feed on any
cultivated Aster or other Asteraceae.

ACKNOWLEDGMENTS

We are grateful to the specialists at the University of Florida, the Division of
Plant Industry of the Florida Department of Agriculture and Consumer Services,
and the USDA Systematic Entomology Laboratory for their assistance in identifying
the insects and plants. Voucher specimens have been placed in the Florida State Col
election of Arthropods. Florida Agric. Expt. Sta. J. Series No. 7861.

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mol. Soc. 37: 227-234.
BORROR, D. J., D. M. DELONG, AND C. A. TRIPLEHORN. 1976. An introduction to the
study of insects, 4th ed. Holt, Rinehart and Winston, New York. 852 pp.
BRAUN, A. F. 1908. Revision of the North American species of the genus Lithocolletis
Hiibner. Trans. Amer. Entomol. Soc. 34: 269.
BRAUN, A. F 1963. The genus Bucculatrix in America North of Mexico (Microlepi
doptera). Mem. Amer. Entomol. Soc. 18: 208.
CALDWELL, J. S. 1938. The jumping plant-lice of Ohio. Ohio Biol. Survey Bull. 5:
241-242.


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cies on Pinus resinosa seedlings. Plant and Soil 57: 363-374.
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to inhibit attack by the parasitoid Torymus capite. Ecology 63: 1602-1605.
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OVERWINTERING AND ESTABLISHMENT POTENTIAL OF
BAGOUS AFFINIS (COLEOPTERA: CURCULIONIDAE) ON
HYDRILLA VERTICILLATA (HYDROCHARITACEAE) IN
NORTHERN CALIFORNIA

K. E. GODFREY1, L. W. J. ANDERSON 1, S. D. PERRY2, AND N. DECHORETZ3
1USDA, ARS, Aquatic Weed Control Research Laboratory,
University of California, Davis, CA 95616

2Aquatics Unlimited, 2150 Franklin Canyon Road, Martinez, CA 94553

3California Department of Food and Agriculture, 1220 N Street,
Sacramento, CA 94271

ABSTRACT

Bagous affinis Hustache (Coleoptera: Curculionidae) has potential as a biological
control agent for subterranean turions (also called tubers) of hydrilla (Hydrilla ver
ticillata (L.f.) Royle; Hydrocharitaceae). The ability of B. affinis to overwinter and es
tablish was investigated at 2 sites in northern California; a pond in Calaveras
County and the Chowchilla River in Madera County. In cage studies conducted at the
pond, B. affinis survived the winter for 2 seasons. After releases at the pond, B. affi
nis successfully reproduced and survived during the summer of 1992. Weevil larvae
had damaged both sentinel and native tubers at the site. In the spring, following the


This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. O. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
This document was created with FrameMaker 4.0.2







Florida Entomologist 77(2)


release of B. affinis at the pond, a light trap and baited shelter traps were used to de
tect weevils that had overwintered naturally at the site. No weevils were recovered.
At the Chowchilla River site, B. affinis failed to establish, possibly due to a lack of tu
bers in the section of the river where the releases were made.
Key Words: Aquatic weed control, biological control, field biology, noxious weeds.

RESUME

Bagous affinis Hustache (Coleoptera: Curculionidae) tiene potential como agent
de control biol6gico, al atacar los tallos subterraneos (tub6rculos) de la Elodea de
Florida (Hydrilla verticillata (L.f.) Royle; Hydrocharitaceae). La habilidad de B. affi
nis para invernar y establecerse fu6 investigada en dos sitios del norte de California:
un estanque en el condado de Calaveras y el rio Chowchilla en el condado de Madera.
En studios enjaulas, llevados a cabo en el estanque, B. affinis sobrevivi6 el invierno
a lo largo de dos estaciones mas. Despu6s de las liberaciones en el estanque, B. affi
nis se reprodujo exitosamente y sobrevivi6 durante el verano de 1992. Las larvas del
picudo danaron tanto los tuberculos secundarios como los tuberculos primaries. En
la primavera, luego de la liberaci6n de B. affinis, se utilize una trampa de luz y tram
pas con cebo para detectar los picudos que habian imvernado en el estanque. No se
recuperaron picudos. En el rio Chowchilla B. affinis no se estableci6, posiblemente
debido a la falta de tub6rculos en la secci6n del rio donde se efectuaron las liberal
ciones.



Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae) has been a serious weed in
ponds, lakes and waterways since its discovery in California in 1976 (California De
apartment of Food and Agriculture 1991). As a part of a state mandated eradication
program designed to reduce the spread and density of H. verticillata (hydrilla), in
fested aquatic sites are quarantined, or closed to fishing and recreation. The hydrilla
then is treated with herbicides, physically removed by dredging, and/or controlled by
release of sterile triploid grass carp, C... .. .,' i .. .. idella (Cuvuer and Valenci
ennes; Cyprinidae). The fish have only been released in canals in the Imperial Irri
gation District. These tactics are very effective against the above-ground portions of
the plant, however, subterranean vegetative propagules, called subterranean turi
ons or tubers, have a greater survival rate when using these tactics than the above
ground portions of the plant. Tubers are the primary cause of reinfestations. Cur
rently, densities of hydrilla tubers are reduced by attrition, use of soil fumigants, or
dredging. Chemical and physical methods are often disruptive to the aquatic envi
ronment. Thus, in an attempt to reduce disruption to wetland environments, biolog
ical control of hydrilla tubers was investigated.
In the 1970's and 1980's, a search was initiated for organisms that fed upon hyd
rilla tubers on the Indian subcontinent (Baloch et al. 1980). A weevil, Bagous affinis
Hustache (Coleoptera: Curculionidae), was found feeding on hydrilla tubers in cen
tral Pakistan (Baloch et al. 1980). The weevil had infested 90-100% of the exposed
hydrilla tubers as waters receded during the dry season. No regrowth of hydrilla oc
curred at this site in the following wet season (Baloch et al. 1980). Bagous affiniswas
imported into quarantine in the United States in the mid 1980's to study its biology
and host plant range (Buckingham 1988). The life cycle in the laboratory was deter
mined, and it was found that the weevil could not withstand submergence [not
longer than 2.5 days (larvae), and not longer than 5 days (adults); Bennett and Buck
ingham 1991]. From studies of host plant range, B. affinis was found to feed and
complete development only on hydrilla (Buckingham 1988).
B. affinis was imported into California in the summer of 1991 to determine if it
could be used to reduce densities of hydrilla tubers biologically. The weevil seemed


June, 1994










well suited to conditions in northern California because in some of the water systems
infested with hydrilla, drawdown conditions exist naturally or may be created artifi
cially. The suitability of B. affinis as a biological control agent for hydrilla tubers in
California was investigated by examining its ability to overwinter and to establish
after release.


MATERIALS AND METHODS

All B. affinis used were the progeny of weevils collected outside Bangalore, India,
in April 1991. The weevils were cultured in quarantine at the Florida Biological Con
trol Laboratory, Gainesville, Florida, for 1 generation before shipment of the weevils
to California. The weevils were maintained in laboratory culture at the USDA
Aquatic Weed Control Research Laboratory, Davis, California, for 2-10 generations
before use in the experiments. Voucher specimens were deposited at the Bohart Mu
seum, Department of Entomology, University of California, Davis, California.
The ability of B. affinis to overwinter in northern California was determined for 2
consecutive fall-spring seasons with caged weevils placed along the bank of a hyd
rilla-infested pond near Mountain Ranch, California, in Calaveras County (approxi
mate lat. 380N, long. 1200W). In the first fall-spring season, the studies were
initiated by placing 35 cages (28.5 cm diam x 35.5 cm height) at the pond on 23 Sep
tember 1991. Each cage contained 10-15 cm of soil in which 50 hydrilla tubers had
been buried at a depth of about 5 cm. Only dioecious hydrilla tubers were used in
these experiments because dioecious hydrilla is the predominant type of hydrilla
found in California. On the soil surface, approximately 20 hydrilla stems covered a 2
cm cube of water-saturated floral foam. The hydrilla stems served as a food source,
and the floral foam, an oviposition substrate. [Floral foam was found to be an accept
able substrate for oviposition, and more convenient to work with in field studies than
water-soaked wood, the natural oviposition substrate (Bennett & Buckingham
1991).] Ten B. affinis adults were placed in each cage. Five randomly selected cages
were returned to the laboratory on the following dates: 15 October, 1 November, and
18 December 1991; 7 February, 3 March, 9 April, and 6 May 1992. On each sample
date, fresh hydrilla stems were added to the cages remaining in the field. The con
tents of the retrieved cages were sorted by examining the hydrilla stems to detect B.
affinis adults, and the soil was washed through a 5-mm sieve to recover tubers. The
tubers were examined for evidence of feeding by B. affinis larvae and to recover any
B. affinis. The number and life stage of any B. affinis, and the number and condition
(i.e., fed upon or not fed upon) of the tubers were recorded.
In the second fall-spring season, the 35 cages were placed at the pond on 21 Sep
tember 1992. The contents of each cage was similar to that in the first season, except
that 25 tubers, and 5 B. affinis adults were placed in each cage. In addition, each
cage contained two 20-ml vials filled with water and stoppered with sponges. Food
and water were replenished every 2 weeks for the first 2 months. For the remainder
of the study, fresh food and water were provided on the following sampling dates: 19
October, 16 November, and 14 December 1992; 19 January, 17 February, 15 March,
and 19 April 1993. The procedures for sorting the contents of the cages were the
same as those used in the first season. The trend in percent of tubers fed upon by B.
affinis was regressed against time for both years using PROC REG (SAS Institute
1982).
During both seasons, the air and soil temperatures within the cages were moni
tored using thermistors connected to a Li-Cor LI-1000 Data L.:- (Lincoln, NE).
Within the cage, the thermistor for the air temperature was positioned approxi
mately 10 cm above the soil surface, and that for the soil, buried approximately 5 cm
below the soil surface. The hourly mean air and soil temperatures were recorded.







Florida Entomologist 77(2)


The establishment potential of B. affinis was investigated at 2 sites in northern
California. The first site was the pond in Calaveras County used for the overwinter
ing studies. Releases of B. affinis eggs and adults were made in 1991 and 1992, re
spectively. The other site was along the Chowchilla River near Raymond, California,
in Madera County (approximately lat. 370N, long. 1200W) where adult weevils were
released in 1991 only. For releases at the pond, the water level had to be drawn
down, and this was done from 21-26 August 1991 and from 18-21 May 1992. Draw
down was necessary to insure access to tubers by B. affinis larvae. On 30 August
1991, the pre-release tuber density in the exposed pond bottom was estimated by
taking three 15-cm diam core samples (sample depth = 10 cm) from each of 15
transects that were arranged in a spoke-like fashion around the pond (total number
of samples = 45). Each transect ran from the edge of the water to the bank of the
pond. The first core in each transect was taken next to the edge of the water, the sec
ond, 1.5 m from the edge of the water, and the third, 3 m from the edge of the water.
On 8 September 1992, after all B. affinis releases had been completed, the post-re
lease density of tubers was estimated as described above except that 25 transects
were sampled (total number of samples = 75). The area of exposed pond bottom sam
pled for the post-release estimate was approximately the same as that for the pre-re
lease estimate of tuber density. Soil cores were bagged, returned to the laboratory,
and washed through a 5-mm sieve. The number and condition (i.e., fed upon or not
fed upon) of the tubers were recorded. The mean pre and post-release densities were
compared using a t-test (Steel &Torrie 1960).
The first set of releases at the pond was made on 24 September 1991 and con
sisted of 3 releases of 50 B. affinis eggs each. The eggs were placed near the edge of
the water at sites thought to have the greatest probability of having tubers. At each
site, pieces of water-soaked wood containing eggs were placed on the surface of the
soil, and covered with a 5-cm layer of moist sphagnum moss. The release site was
covered with a wire-mesh cage (mesh size 2.5 x 3.5 cm; cage diam 75 cm, height 1.2
m) to exclude cattle that used the pond for water. On 15 October 1991, the soil
around (diam of area removed = 40 cm) and under (depth =10 cm) the release site
was placed in a plastic bag and returned to the laboratory. The soil was washed
through a 5-mm sieve to recover tubers, and the number and condition of any tubers
recovered were recorded.
In the second set of releases, 500 B. affinis adults were released on the following
dates: 21 May (200), 17 June (100), 15 July (100), and 11 August 1992 (100). On each
release date, the weevils were divided among 4 randomly chosen sites near the edge
of the water. At each release site, weevils were provided hydrilla stems, a 2-cm cube
of water-saturated floral foam, and a source of free water. To monitor the success of
each release, we buried a mesh bag (1 x 1 cm mesh) containing 25 tubers 5 cm below
each release site. These tubers were used as "sentinel" tubers to monitor feeding ac
tivity by B. affinis larvae. The release site was covered with a screen made of Saran"
screening (Lumite-Synthetic Industries, Gainesville, GA; 32 x 32 mesh) to keep birds
and other small animals out of the release site. The sentinel tubers were recovered
25-30 days after release. The tubers were broken in half to determine the presence of
B. affinis. The number and life stage of any B. affinis found, and the number and con
edition of the sentinel tubers were recorded. During the releases, the mean hourly am
bient air temperature and soil temperature (5 cm below the soil surface) were
monitored using thermistors connected to a Li-Cor LI-1000 Data L:..- (Lincoln,
NE).
To determine if any B. affinis produced as a result of the releases in 1992 survived
the winter, 2 types of traps, black light and baited shelter trap, were deployed
around the pond during the spring of 1993. The black light (UV, 365 nm) trap, sus
pended by a frame 1.5 m above the soil surface on the bank of the pond, was used to
attract emerging weevils in "flight mode" (i.e., energy resources directed toward the


June, 1994










development of indirect flight muscles; Bennett & Buckingham 1991). The insects at
tracted to the light were collected in ajar (1 liter) containing a 1:1 mixture of ethyl
ene glycol and water. The trap was operated for 3 consecutive days per week
beginning 19 April and ending 26 May 1993. The contents of the jar were sorted un
der 10X magnification.
The baited shelter trap was used to attract weevils that were in "reproductive
mode" (i.e., energy resources directed toward the reproductive system, not the indi
rect flight muscles; Bennett & Buckingham 1991). Each shelter trap consisted of a 1
liter container (diam = 12 cm; height =12 cm) that contained soil and 25 tubers bur
ied 5 cm below the soil surface. A 2-cm cube of water-saturated floral foam and a
mesh bag (1 x 1 cm mesh) containing hydrilla stems were placed on the soil surface.
Each trap was covered with a screen (2.5 x 3.5 cm mesh) to exclude other animals.
Each week of light trapping, 5 baited shelter traps were buried in the soil around the
light trap such that the top rim of the container was flush with the surrounding soil
surface, much like a pitfall trap. The shelter traps were left in the field for 1 week.
Upon return to the laboratory, the hydrilla stems from the tops of the traps were ex
amined to recover any adult weevils. The soil within the trap was covered with moist
sphagnum moss, and the traps were held for 30 days under standard rearing condi
tions [270C, 14:10 (L:D)] to allow any B. affinis immatures to develop to the adult
stage. The contents of the traps were examined, and the number of B. affinis recov
ered was recorded.
The second B. affinis release site in California was along the Chowchilla River.
This site was selected because the river goes through a natural low water period.
Most of the river bed was exposed from mid summer through early fall. The density
of hydrilla in the river was low because the river had been treated with herbicides for
the past 5 years in an attempt to eradicate hydrilla. The release site was a small pool
that had a few hydrilla plants and tubers. The density of hydrilla tubers within the
pool could not be quantitatively estimated without destroying the site. Bagous affinis
adults were released on 11 October (200) and 25 October 1991 (103). The site was left
undisturbed until 12 November 1991 when the site was sampled for tubers. Stan
dard tuber sampling (i.e., using a 15-cm diam core sampler) was attempted, but
abandoned because the soil in the bottom of the pool was a very fine sand that did not
hold together as the sampler was pulled up through the 60 cm of water covering the
site. Instead, a shovel was used to remove soil from the bottom of the pool. The soil
was washed through a 5-mm sieve to recover tubers. The number and condition of tu
bers recovered were recorded.
To determine if B. affinis had overwintered and established at the Chowchilla
River site, we used black light trapping and tuber sampling. Black light trapping (as
described above) was done continuously from 23 -27 April and from 30 April -4 May
1992. The ambient air temperature at the site was recorded during trapping with a
recording thermometer (PTC Instruments Los Angeles, CA).
The river bed was sampled during the summer, the natural low water period. If B.
affinis had established at this site, then feeding damage should have been evident on
the tubers. Tubers were sampled by taking fifty 15-cm diam core samples (depth of
sample 10 cm) on 9 July and 21 August 1992 (total number of samples = 100) from
a 30-m section of the river. The midpoint of this section of river was the release site.
Transects traversed the river bed at 3 m intervals beginning at the release site and
running up and down river. Five cores were taken from the release site and from
each transect. The core samples were washed through a 5-mm sieve to recover tu
bers. The number and condition of the tubers recovered were recorded.






Florida Entomologist 77(2)


RESULTS

Bagous affinis survived the winter in cages at the pond in Calaveras County in
1991 1992 and in 1992 -1993 (Table 1). In the first season, 2 adults were recovered
on the 9 April 1992 sampling date (Table 1). These individuals were in all likelihood
the F1 progeny of the adults originally placed within the cages because the mean
number of tubers fed upon and the percent of tubers fed upon increased with the
length of time the cages were in the field (Table 1). Linear regression of the percent
of tubers fed upon against time resulted in a significant positive regression (F = 54.2;
df = 1,5; P < 0.05; R2 = 0.92). Much of this feeding damage was characteristic of that
produced by B. affinis larvae. This trend in feeding activity suggested that B. affinis
was successfully reproducing within the cages. In addition, in the laboratory under
optimal conditions, B. affinis adults survive a mean of 127.5 days (range 55 -225
days; Bennett &Buckingham 1991). The 9 April 1992 sampling date was 231 days af
ter the cages were placed in the field.
In the second season, 4 adults were recovered, 3 from the samples taken on 17
February, and 1 from the 15 March 1993 sampling date (Table 1). These individuals
also were in all likelihood the progeny of adults originally placed within the cages be
cause as in the first season, the percent of tubers that had been fed upon increased
with the length of time the cages were in the field (Table 1). Linear regression of the
percent of tubers fed upon against time resulted in a significant positive regression
(F = 40.3; df = 1,5; P < 0.05; R2 = 0.89). In addition, the 17 February and the 15 March
sampling dates are 150 and 177 days after the initial placement of the cages in the
field, respectively. The 3 adults recovered from the 17 February sampling date began
ovipositing about 7 days after being brought into the laboratory and produced 44
progeny when held under rearing conditions. These results show that B. affinis can
successfully reproduce after overwintering in northern California.
The mean number of tubers recovered in both seasons decreased with the length
of time the cages were in the field (Table 1). This decrease was due to the degradation
of tubers either naturally or after having been fed upon by B. affinis larvae. Van &
Steward (1990) found that some tubers will degrade naturally through time. The
reason for this degradation is not known. In the degradation of tubers through the
feeding activity of B. affinis, the larvae provide an opening for other organisms to en
ter and attack the tuber. In some cases, entire tubers were destroyed, whereas in oth
ers, whole tubers and pieces of tubers were recovered.
TABLE 1. TOTAL NUMBER OF B. AFFINIS RECOVERED, THE MEAN NUMBER (STD. DEV.)
OF TUBERS RECOVERED, THE MEAN NUMBER (STD. DEV.) OF TUBERS FED
UPON BY B. AFFINIS LARVAE, AND THE PERCENT OF TUBERS FED UPON
FROM THE OVERWINTERING STUDIES CONDUCTED AT THE POND IN CALA
VERAS COUNTY IN 1991-1992 AND 1992-1993. THE MAXIMUM NUMBER OF
TUBERS RECOVERABLE WAS 50 IN 1991-1992 AND 25 I N 1992-1993.

Mean Mean
No. of No. of No. of Percent
B. affinis Tubers Tubers of Tubers
Date Recovered1 Recovered Fed Upon Fed Upon
1991 1992
15 October 2A 48.2 3.2 6.6
(1.64) (2.17)
1 November 1A 37.8 4.2 11.1
(7.69) (2.68)
18 December 1A 32.0 8.6 26.9
(15.87) (2.19)
7 February 0 26.8 7.4 27.6


June, 1994






227


TABLE 1.(CONTINUED) TOTAL NUMBER OF B. AFFINIS RECOVERED, THE MEAN NUM
BER (STD. DEV.) OF TUBERS RECOVERED, THE MEAN NUMBER (STD. DEV.) OF
TUBERS FED UPON BY B. AFFINIS LARVAE, AND THE PERCENT OF TUBERS
FED UPON FROM THE OVERWINTERING STUDIES CONDUCTED AT THE POND
IN CALAVERAS COUNTY IN 1991-1992 AND 1992-1993. THE MAXIMUM
NUMBER OF TUBERS RECOVERABLE WAS 50 IN 1991-1992 AND 25 I N 1992
1993.
Mean Mean
No. of No. of No. of Percent
B. affinis Tubers Tubers of Tubers
Date Recovered1 Recovered Fed Upon Fed Upon


(10.33)


(3.29)


3 March 0 23.8 7.2 30.3
(13.61) (4.92)
9 April 2A 17.8 9.4 52.8
(5.79) (7.92)
6 May 0 28.4 14.4 50.7
(12.36) (6.31)
1992 1993
21 October 2L 18.8 10.4 55.3
(4.21) (3.21)
16 November 1L 16.4 9.8 59.8
(4.51) (2.86)
14 December 1A 9.4 6.6 70.2
(3.05) (2.97)
19 January 0 10.4 8.2 78.9
(5.37) (4.15)
17 February 3A 4.6 4.4 95.7
(2.61) (2.51)
15 March 1A 3.8 3.6 94.7
(2.39) (2.30)
19 April 0 2.6 2.4 92.3
(4.77) (4.34)
1L larva, A Adult.

The soil and air temperatures within the cages were similar for both fall-spring
seasons. At no time during these time periods did the soil temperatures within the
cage drop below 10C or rise above 290C. The air temperatures within the cages were
more variable. The lowest air temperatures ranged from 8.5 to 13.20C in mid-win
ter, and the highest air temperatures ranged from 43.6 to 45.30C in the fall.
Releases of B. affinis at the pond resulted in successful reproduction and survival
by B. affinis in the summer of 1992. For the first set of releases in which B. affinis
eggs were released, establishment of the weevil could not be monitored because no
tubers were found at the release sites. For the second set of releases, however, senti
nel tubers were used to monitor establishment. From the weevils released on 21 May
1992, 5 pupae and 2 adults were recovered from sentinel tubers (Table 2). For the
other release dates, no weevils were recovered from the sentinel tubers, however,
some tubers had been fed upon by B.affinis larvae (Table 2). The air and soil (5 cm
depth) temperatures during the releases were in a range suitable for B. affinis repro
duction and development.







Florida Entomologist 77(2)


To further investigate the establishment of B. affinis at this site, the density of
native tubers was estimated before and after releases of B. affinis. Before the release
of any B. affinis, the native tuber density within the pond was estimated as 0.82 tu
bers per 15-cm core (Table 3). After all releases were complete, the native tuber den


TABLE 2. THE MEAN NUMBER (STD. DEV.) OF SENTINEL TUBERS RECOVERED, THE
MEAN NUMBER (STD. DEV.) OF SENTINEL TUBERS FED UPON, AND THE TOTAL
NUMBER OF B. AFFINIS RECOVERED FROM SENTINEL TUBERS FROM RE
LEASES OF B. AFFINIS ADULTS MADE AT A POND IN CALAVERAS COUNTY IN
1992.

Mean No. of Mean No. of
Sentinel Sentinel Total
Sampling Tubers Tubers B. affinis
Date Recovered Fed Upon Recovered1
21 May 23.0 6.0 5P,2A
(0.82) (2.71)
17 June 24.332 1.33 0
(1.15) (0.58)
15 July 24.5 2.75 0
(0.58) (1.26)
11 August 25.0 0.75 0
(0.82) (0.96)
11 = pupa, A = adult.
2One release site destroyed by cattle. Maximum total recoverable sentinel tubers = 75.



sity within the pond was estimated as 0.12 tubers per 15-cm core (Table 3). This
apparent decrease in native tuber density was not statistically significant (P > 0.05).
However, 22% of the native tubers recovered had feeding damage that resembled
that imparted by B. affinis larvae. We assume that this feeding damage had been
caused by B. affinis because no native organisms are known to feed inside hydrilla
tubers in the United States (Balciunas & Minno 1985).
Light and baited shelter traps operated in the spring of 1993 did not capture any
overwintering progeny from B. affinis released at the pond in the summer of 1992.
However, 6 of the 125 tubers (4.8%) examined in the last set of baited shelter traps
(placed in the field 24 May 1993), had damage resembling that caused by B. affinis
larvae.
Releases of B. affinis made along the Chowchilla River did not result in establish
ment of the weevil. Six tubers were recovered from samples collected approximately
30 days after release. Of these tubers, 2 had damage characteristic of B.affinis larval
feeding, suggesting that the weevils initially released at this site were successful in
reproducing. In subsequent monitoring of the site, no weevils were captured by the
light trap, and no tubers (i.e., tuber density = 0 tubers per 15 cm-core) were recov
ered in the tuber sampling of the river. The absence of hydrilla tubers in this section
of the river was due to hydrilla plant removal and treatment of the river with herbi
cides in previous years. Given the lack of tubers in this section of the river, it seems
unlikely that B. affinis could have survived without food resources even if it could
overwinter at the site.


June, 1994










TABLE 3. THE MEAN NUMBER (STD. DEV.) OF HYDRILLA TUBERS RECOVERED IN 15-CM
CORE SAMPLES FROM THE EXPOSED POND BOTTOM IN CALAVERAS COUNTY.

Transects
Overall
Water's 1.5 m from 3 m from Mean No.
Sampling Date Edge Water's Edge Water's Edge of Tubers
30 August 1991 0.13 0.40 1.93 0.82
(0.35) (0.83) (2.60) (10.67)
8 September 1992 0.12 0.16 0.08 0.12
(0.44) (0.47) (0.28) (3.52)


DISCUSSION

Bagous affinis demonstrated an ability to adapt to the climate in northern Cali
fornia. Adult weevils were able to survive the winter within cages despite soil tem-
peratures dropping to near 10C and air temperatures approaching 140C. These cold
temperatures did not appear to reduce the reproductive success of the weevils be
cause weevils recovered from overwintering cages produced progeny in numbers
equivalent to those weevils in the colony when placed under normal rearing condi
tions.
The ability of the weevils to survive the winter within the cages suggested that
the weevils may also be able to overwinter naturally. However, no naturally-overwin
tering weevils were trapped at either release site in light traps. This is not surprising
considering that the greatest attraction to a light trap by a particular species of in
sect occurs within a narrow range of environmental conditions. For B. affinis, the en
vironmental conditions for maximum attraction to a light trap include temperatures
at sunset at or above 200C and little or no wind (Buckingham et al. 1994). For both
release sites, the temperature at sunset was at or above 200C for about half of the
trapping days; however, on all trapping days light to moderate winds prevailed. In
addition, for B. affinis to be attracted to the light trap, the weevils would have to be
in "flight mode", not "reproductive mode". The density of weevils that may have over
wintered naturally also would not have been large, thereby making it difficult to de
tect weevils using light traps.
The baited shelter traps should have been more attractive to any naturally-over
wintering B. affinis that were in reproductive mode than the light traps. No weevils
were recovered from the traps, but a small amount of feeding damage was detected
in the tubers from the traps. This feeding damage suggests that the density of over
wintering weevils was probably very low.
Given its demonstrated ability to overwinter, it is not surprising that the weevil
successfully reproduced using native tubers at 1 of the 2 release sites. Its failure to
establish at the Chowchilla River site was probably due to the lack of tubers in the
part of the river where it was released. In order for B. affinis to establish, it must
have a food resource. At the pond in Calaveras County, the weevil reproduced suc
cessfully and survived through the summer of 1992. Evidence of its reproduction and
survival was found in both sentinel and native tubers. In the sentinel tubers, B. affi
nis immatures were recovered after the first release, and tubers damaged by B. affi
nis were recovered in subsequent releases (Table 2). The lack of recovery of B. affinis
in the later releases can be explained by the developmental rate of B. affinis. For the
first set of releases, the soil temperature at 5 cm (the depth of the sentinel tubers)
was near 2 10C. At 2 10C, the development of B. affinis from larva to adult requires ap
proximately 30 days (K.E.G., unpublished data). Given a short amount of time for
oviposition and egg hatch, it was expected that the sentinel tubers recovered about
30 days after release would contain B. affinis immatures. For the remaining re







Florida Entomologist 77(2)


leases, the soil temperature at 5 cm increased to 25 -280C. The development of B. af-
finis from larva to adult requires approximately 20 and 12 days at 25 and 280C,
respectively (K.E.G., unpublished data). Again, given a short period of time for ovi
position and egg hatch, it was expected that B. affinis could have completed develop
ment leaving only damaged tubers.
Of the native tubers recovered from the pond after all B. affinis releases were
complete, 22% had been fed upon by B. affinis. This level of tuber damage was within
the range of tuber damage found by Buckingham et al. (1994) at a lake in Florida
where B. affinis had successfully survived and reproduced for 3 months. They found
from 0.57 -32% of the tubers recovered from the lake had been fed upon by B. affinis.
In addition, they found degradation of the tubers after B. affinis feeding as we did in
this study.
Bagous affinis has potential as a biological control agent for hydrilla tubers in
California. This weevil could be used as one element in the long-term management
strategy to reduce numbers of hydrilla tubers. To do this, B. affinis should be re
leased at sites that undergo annual drawdowns and have tuber densities sufficient to
sustain populations of the weevil from year to year. In addition, B. affinis could also
be used in more intensive, short-term management of hydrilla tubers through inun
dative releases at sites where more rapid reductions of tuber numbers are required.


ACKNOWLEDGMENT

We acknowledge S. Krishnaswamy for collecting and shipping the weevils from
India; and T. Sankaran for arranging collection, packaging, and delivery of the wee
vils from India to Florida. We also acknowledge C. Bennett and G. Buckingham for
quarantine handling and initial colonization of the weevils. We also acknowledge the
assistance given by R. O'Connell, R. Ng, and F. Zarate in locating sites, in the main
tenance of water levels at the pond and in tuber sampling. We thank D. Spencer, G.
Buckingham, and C. Turner for reviewing an earlier draft of the manuscript. Re
search supported by a grant from the California Department of Food and Agricul
ture. Mention of a proprietary product does not constitute an endorsement or a
recommendation for its use by USDA.


REFERENCES CITED

BALCIUNAS, J. K., AND M. C. MINNO. 1985. Insects damaging Hydrillain the USA. J.
Aquat. Plant Manage. 23: 7783.
BALOCH, G. M., SANA-ULLAH, AND M. A. GHANI. 1980. Some promising insects for the
biological control of Hydrilla verticillata in Pakistan. Trop. Pest Manage. 26:
194-200.
BENNETT, C. A., AND G. R. BUCKINGHAM. 1991. Laboratory biologies of Bagous affinis
and B. laevigatus (Coleoptera: Curculionidae) attacking tubers of Hydrilla
verticillata (Hydrocharitaceae). Ann. Entomol. Soc. America 84: 420-428.
BUCKINGHAM, G. R. 1988. Reunion in Florida -Hydrilla, a weevil, and a fly. Aquatics
10: 19-25.
BUCKINGHAM, G. R., C. A. BENNETT, AND E. A. OKRAH. 1994. Temporary establish
ment of the hydrilla tuber weevil (Bagous affinis) during a drawdown in
north-central Florida. J. Aquat. Plant Manage. 32: (in press).
CALIFORNIA DEPARTMENT OF FOOD AND AGRICULTURE. 1991. Hydrilla verticillata.
Detection Manual. Rev. 10/11/91. 3pp.
SAS INSTITUTE, INC. 1982. SAS User's Guide: statistics. 1982 Edition, Cary, NC.
STEEL, R. G. D., AND J. H. TORRIE. 1960. Principles and procedures of statistics.
McGraw-Hill Book Company, Inc. NY.
VAN, T. K., AND K. K. STEWARD. 1990. Longevity of monoecious hydrilla propagules.
J. Aquat. Plant Manage. 28: 7476.


June, 1994






Sutton & Steck: Discrimination of Fruit Fly Larvae


DISCRIMINATION OF CARIBBEAN AND MEDITERRANEAN
FRUIT FLY LARVAE (DIPTERA:TEPHRITIDAE) BY
CUTICULAR HYDROCARBON ANALYSIS


BRUCE D. SUTTON AND GARY J. STECK
Division of Plant Industry
Florida Department of Agriculture and Consumer Services
Gainesville FL 32614-7100


ABSTRACT

Larvae of the Caribbean fruit fly, Anastrepha suspense (Loew) can be different
ated from those of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) with
nearly 100% accuracy by analysis of cuticular hydrocarbon (CHC) patterns. A dis
criminant model is presented based on samples of feral and laboratory Caribbean
and Mediterranean fruit flies. The difference in the ratio of two components is suffi
cient to discriminate third instars of the species. Accuracy in discrimination, utiliza
tion of specimens that are damaged, dried or otherwise unusable for morphometric,
isozyme or DNA analysis, low cost per sample and automation of the process, all
make CHC analysis a particularly effective solution for identification of these two
species.
Key Words: Anastrepha suspense, Ceratitis capitata, gas chromatography, discrimi
nant analysis.

RESUME

Las larvas de la mosca Caribena de las frutas, Anastrepha suspense (Loew) y las
de la mosca del mediterraneo, Ceratitis capitata (Wiedemann) pueden ser diferencia
das entire si con aproximadamente un 100% de precision mediante analisis de los pa
trones de los hidrocarburos cuticulares. Se present un modelo para ambas moscas
basado en muestras ferales y de laboratorio. La diferencia en la relaci6n de dos com-
ponentes es suficiente para discriminar terceros estadios de cada especie. La pre
cisi6n en la discriminaci6n, la posibilidad de trabajar con especimenes que se
encuentran danados, secos, o de alguna manera inutilizables para el analisis morfo
metrico, de isozimas o DNA, el bajo costo por muestra y la automatizaci6n del pro
ceso, hacen el analisis de hidrocarburos una soluci6n particularmente efectiva para
la identificaci6n de estas dos species.




The state of Florida, as a major producer and exporter of fruits and vegetables,
maintains a number of programs to deal with tephritid fruit fly pests. Anastrepha
suspense (Loew), the Caribbean fruit fly or caribfly, successfully invaded and rapidly
colonized the southern half of the state during the 1960's (Clark & Weems 1989) ne
cessitating costly treatment and population monitoring programs to protect commer
cial crops from damage, and to certify fruit free of this insect for exportation (Riherd
1993). Additionally, state and federal agencies maintain a vigilant quarantine and
trapping program to minimize introductions and provide early detection of other ex
otic fruit flies [e.g. Ceratitis capitata (Wiedemann), Mediterranean fruit fly or medfly,
or other Anastrepha species]. Once new fruit fly introductions are detected, usually
by capture of adult fruit flies in specially baited traps, a well-defined action plan
must go into effect. Captured flies are identified and evaluated for reproductive con
edition, trap density in the vicinity of the original trap site is intensified, and fruits, if
present, are checked for the presence of larvae. Detection of an active infestation of

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. O. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
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Florida Entomologist 77(2)


an exotic species and its focal point, i.e., fertile adults ovipositing into susceptible
fruits and producing viable larvae, is critical before undertaking an effective action
plan. Due to the widespread occurrence of A. suspense, however, Florida faces a spe
cial problem in finding such focal points. In practical terms, we face a needle-in-a-
haystack problem if the new detection occurs in an area where A. suspense is already
actively breeding. Accurate identification of fruit fly larvae is difficult to impossible
given current knowledge (Steck et al. 1990). The problem in Florida is simplified to
the extent that the identification is an either-or decision, i.e., A. suspense or newly
detected exotic. The third instar of A. suspense has been described in useful detail by
Heppner (1984) and is included in the key of Steck et al. (1990), but other immature
stages of this species have not been adequately described. Immature stages of medfly
also have been described (Phillips 1946, Hardy 1949). Usually it is possible to differ
entiate larvae of the two species using morphological criteria; however, the natural
range of morphological variability includes overlap in character state distributions,
and some specimens (especially earlier instars) cannot be reliably identified. About
10% of A. suspense and C capitata larvae fall into the indeterminate category [H.A.
Denmark, Florida Department of Agriculture and Consumer Services (FDACS),
pers. comm.]. Given the economic costs that may accrue from the mis-identification
of fruit fly larvae, it is desirable that effective adjuncts to morphological identifica
tion of larvae be found and implemented.
In this paper we describe the use of cuticular hydrocarbon (CHC) analysis to dif
ferentiate C. capitata and A. suspense immature stages. Carlson & Yocom (1986) pro
vided the groundwork for this analysis by describing CHC chromatographic patterns
of six economically important fruit fly taxa including C. capitata and A. suspense.
The third instar larvae of A. suspense and C. capitata were found to exhibit quanti
tatively different hydrocarbon patterns. More recently, Sutton & Carlson (1993) in
vestigated CHC variation in larvae of A. fraterculus (Wiedemann), A. obliqua
(Macquart), A. suspense and other Anastrepha taxa and constructed discriminant
models. Unfortunately, it is not possible to reconstruct realistic classification error
estimates from the sample statistics as published, given the limited number of sam
ples and the potential bias to which it could lead. Thus, it is necessary to sample the
range of variation before an effective discriminant model can be constructed that not
only distinguishes between A. suspense and C. capitata larvae based upon CHC pat
terns, but also specifies robust classification error rates. Consequently, we have ex
tended the previous analyses to include representative samples of third instar A.
suspense larvae from a number of host fruits in Florida and the Caribbean, and third
instar C. capitata larvae from various hosts in Central America and Hawaii. A small
number of second instar larvae was also analyzed.

MATERIALS AND METHODS

A total of 159 third instar larvae of A. suspense was analyzed. The samples orig
inated from eight feral collections in Dade County, Florida, taken from loquat (Erio
botryajaponica (Thumb.) Lindl.), calamondin (Citrofortunella x mitis Blanco), guava
(Psidium guajava L.), cattley guava (Psidium cattleianum Sabine), Surinam cherry
(Eugenia uniflora L.) and tropical almond (Terminalia catappa L.); one feral collec
tion from Lake Co., Florida, from guava; and four collections from Puerto Rico from
guava and tropical almond. Additional third instar larvae of A. suspense were ob
stained from the USDA-ARS laboratory colony (Gainesville, FL) and the FDACS
mass-rearing facility (Gainesville, FL), together with 12 second instar larvae.
C. capitata samples comprised 99 specimens of third instar larvae taken from six
feral collections in Hawaii originating from coffee (Coffea arabica L.), persimmon
(Diospyros kaki L. f.), and Jerusalem cherry (Solanum pseudocapsicum L.); samples
from the USDA-APHIS mass-rearing facility at Waimanalo and the USDA-ARS col


June, 1994







Sutton & Steck: Discrimination of Fruit Fly Larvae


ony at Waimea; one feral collection from calamondin from Guatemala, and samples
from laboratory colonies at USDA-APHIS and the Petapa mass-rearing facility. A to
tal of 12 second instar larvae was obtained from the Waimanola facility and two feral
second instars were collected from coffee in Hawaii.
All specimens are vouchered with the Florida State Collection of Arthropods,
FDACS, Gainesville, Florida.
Individual whole larvae (fresh, freshly frozen, or dried) were extracted and pre
pared as previously described (Carlson & Yocom 1986, Sutton & Carlson 1993). GC
analyses were made with a Tracor Model 540 Gas Chromatograph (Austin, TX) fitted
with a nonpolar fused silica capillary column (BP-1, 50 m x 0.15 mm id, 0.25 pm film
thickness, Scientific Glass Engineering, Austin, TX), cool on-column injector (OCI-3,
Scientific Glass Engineering, Austin, TX) and Tracor flame-ionization detector. Puri
fled hydrogen was used as the carrier gas at a pressure of 80 psi providing a linear
flow-rate of 35-45 cm/s; the oven was temperature programmed from 60-2250C at 200
per minute, and 225-3200C at 1.50 per minute.
Areas were calculated for each of the selected peaks for each sample using the
Nelson Model 2100 Chromatography Data System, Revision 5.0 (Nelson Analytical,
Inc., Cupertina, CA). The SAS System, Version 6.01, (SAS Institute, Inc., Cary, NC)
was utilized for the discriminant analysis and the density plot was constructed using
Sygraph, Version 1.1 (SYSTAT, Inc., Evanston, IL).

RESULTS AND DISCUSSION

The CHC composition of larvae of A. suspense and C. capitata is dominated by
homologous series of n-alkanes and 2-monomethylalkanes with lesser quantities of
other mono and dimethylalkanes (Carlson & Yocom 1986, Sutton & Carlson 1993).
The unsaturated hydrocarbons of A. suspense larvae include squalene together with
small quantities of as yet unidentified components (Sutton & Carlson 1993). Chro
matograms of third instar A. suspense and C. capitata extracts (Figure 1) exhibit
consistent quantitative differences in the relative proportions of 2-methyloctacosane
at Kovats Index (KI) (Kovats 1965) 2865 and 2-methyltriacontane at KI 3065 (Table
1). A density plot of the In transformed ratios of the peak areas at KI 2865 and KI
3065 [R65 In (KI 2865 peak area/KI 3065 peak area)] with an Epanechakov kernel
density estimator (Silverman 1986) (Fig. 2) resulted in unimodal distributions for A.
suspense and C. capitata having well separated modes and a small amount of over
lap in the distribution tails. No consistent quantitative differences in CHC pattern
were evident between feral Puerto Rico and Florida A. suspense, nor between Hawaii
and Guatamala C. capitata. Likewise, the laboratory colonies of C. capitata exhibited
R65 values within the range of variation seen in wild collections. The R65 values for
feral Florida A. suspense are consistent with those reported previously (Carlson &
Yocom 1986); however, the A. suspense colony maintained for many years by USDA
ARS, Gainesville, as well as the extant colony at FDACS, Gainesville, exhibited R65

TABLE 1. UNIVARIATE STATISTICS FOR THE LN OF THE RATIO OF THE PEAK AREAS AT
KI 2865 AND KI 3065 (R65), FOR THIRD INSTAR LARVAE OF A. SUSPENSE
AND C CAPITATA.

A. suspense C capitata
N 159 99
Mean 3.45 0.05
S.D. 2.80 0.15
Minimum 1.43 3.50
Maximum 4.54 2.14






Florida Entomologist 77(2)


KI2865


Anastrepha suspense


KI 2900
KI 2820 KI 3065
K 2KJ2975Kj3000 KI3100
K12800 KI 296- /
^s^Alm


Ceratitis capitata




KI 2900


KI2865


RETENTION TME -*
Fig. 1. Capillary gas chromatograms of hydrocarbons extracted from individual
third instar larvae of tephritid fruit flies: a. A. suspense, b. C. capitata.

values substantially lower than those seen in wild collections. This was confirmed by
reexamination of CHC patterns from a later sampling (Sutton & Carlson 1993) of the
USDA colony. The reduced R65 values in the USDA colony are the consequence of an
as yet unidentified eluant of KI 3060 that co-elutes with the KI 3065 peak under the
chromatographic conditions used in the previous studies. This peak is also present in
wild A. suspense from Florida and Puerto Rico but in much reduced quantities com
pared to those seen in individuals from the USDA colony. The origin of the FDACS
colony is unclear, but it probably originated from the USDA colony. To avoid this bias,
only wild A. suspense or laboratory colonies recently established from wild individu
als were used for comparison with C. capitata. There was no evidence that CHC pat
terns are correlated with host fruits for either species.


June, 1994






Sutton & Steck: Discrimination of Fruit Fly Larvae


Ceratitis capitata


Anastrepha


suspense

/


0 1.1 2.3


Ln KI 2865 / KI 3065
Fig. 2. Density plot using a kernel density estimator with Epanechakov kernel for
the In transformed ratio of the areas of the 28-and 30-carbon backbone 2-mono
methylalkane peaks (R65) for A. suspense and C. capitata. Cross-hatching indicates
the region of possible overlap.

The specification of a decision criterion and reliability estimates for classification
errors based upon R65 values for third instar larvae of A. suspense and C. capitata
depends upon the accurate reconstruction of the distribution tails for each species
and the degree of overlap between them. Our sample distributions exhibited a small
degree of overlap in the region of 1.10 < R65 < 2.30. Given the economic costs of mis
identification, it is safer to assume that even this sampling may be insufficient to
fully describe population distributions in the range of possible overlap. A linear dis
criminant model resulted in jack-knifed classification errors of 0.63% and 2.02% for
A. suspense and C. capitata, respectively. However, given that false negative errors
are potentially more costly than false positives, a more conservative bias is indi
cated. The values for A. suspense drop off sharply for R65 less than 2.30, with only 3%
(5 of 159 individuals) below 2.30; a single wild individual had an R65 value less than
2.08. Three percent (3/99 individuals) of the third instar C. capitata larvae exhibited
R65 values within the interval (1.10,2.30), with two individuals having R65 values
greater than 1.39. Any specific value is somewhat arbitrary given the uncertainties
involved, but a classification threshold of about R65 = 2.30 would seem appropriate.







Florida Entomologist 77(2)


Rare individuals of A. suspense (3% or so) would be expected to exhibit R65 values be
low this threshold and would classify as C capitata. Thus, we must accept the possi
ability of false positives for larvae having R65 values in the range of 1.10 to 2.30.
It should be noted that all third instars analyzed could be correctly identified vi
usually using secondary aspects of the hydrocarbon patterns (Fig. 1). Low R65 values
in A. suspense were due more to variation in the KI 2865 peak than to variation in
the KI 3065 peak, i.e., the latter peak remains small with respect to the overall pat
tern. Similarly, higher R65 values in C. capitata are a consequence of a relative in
crease in the KI 3065 peak rather than a significant reduction in the KI 2865 peak so
that the KI 3065 peak remains large with respect to the overall pattern. Unfortu
nately, such aspects of chromatographic patterns are difficult to quantify, and inter
pretations based upon small peaks can be rendered difficult, if not impossible, by
suboptimal chromatographic conditions.
Second instar larvae of A. suspense and C capitata from laboratory colonies ex
hibited significant quantitative shifts of the CHC pattern compared to third instars.
In both species, second instars show a relative increase in the KI 2865 peak and a re
duction in the KI 3065 in comparison to the third instar larvae. A. suspense from the
FDACS colony exhibited mean R65 values of 4.16 + 2.09 (n=12) and 2.09 + 0.88 (n 12)
for second and third instars, respectively. No feral second instars of A. suspense were
available for analysis. The R65 values for second and third instar larvae of C. capitata
from the lab colony at Waimea were 1.26 + 0.60 (n 12) and 0.58 0.03 (n=12) respect
tively. Two feral C. capitata second instars showed corresponding R65 values of 2.36
and 2.81. It is unclear whether there is a more or less continuous shift in the 2 mono
Iri. I,, ,l ii, , i., .i, ,-. or if the CHC pattern remains relatively invariant over
a larval stage. The sampling of second instars was insufficient to construct a realistic
classification model; however, it is clear that use of the third instar model would re
sult in a substantial increase in mis-classified C. capitata second instars.
Larvae utilized for analysis were either fresh, fresh-frozen or dried. Alcohol pre
served specimens generally did not give clean chromatograms and are not recom-
mended for use in CHC analysis. The CHC patterns were not appreciably altered by
larval decomposition or physical damage; hence it is possible to utilize specimens
that are not identifiable by other means. Very good extractions were also obtained
from larval skins alone, e.g. following removal of internal contents for protein elec
trophoresis or other analysis. Thus, CHC analysis is compatible with simultaneous
analysis of a single specimen by both morphological and biochemical or molecular
means. Given the possible economic ramifications of misidentification and the ease
with which the analysis of a critical individual may be botched, it is imperative that
alternative identification systems be available for backup and/or verification. This is
particularly important in the case of larvae having R65 values in the region of possi
ble overlap between the two taxa.
We found use of 28-200 mesh activated silica gel to be a particularly effective
method for drying larvae in the field. While this procedure precludes the use of the
larvae for analyses such as protein electrophoresis, solvent extraction of specimens
dried in silica gel was significantly enhanced in comparison to fresh or frozen mate
rial. Possibly there are highly polar or hydrophilic components in the larval cuticle
that shield the hydrocarbons from the non-polar solvent used for extraction, but are
removed by adsorption onto the silica gel.
Implementation of CHC analysis for the discrimination of larvae of A. suspense
and C. capitata will require further development. No attempt was made in this study
to optimize either the larval extraction procedure or the gas chromatography param
eters to minimize analysis time and cost. Further sampling will be required to con
struct a reliable discriminant model for second instar larvae. In addition, the
potential exists to adapt and/or extend CHC analysis to the identification of other
economically important species, especially Bactrocera, Dacus and other Anastrepha
species.


June, 1994







Mitchell & Tumlinson: Response to Pheromone


ACKNOWLEDGMENT

We gratefully acknowledge the assistance of several colleagues in providing spec
imens. These include S. Bloem, H. Chang, M. J. Hayes, M. Hennessey P. J. Landolt,
L. Stange, and R. Vargas. We also thank D.A. Carlson and S.R. Yocom for reviewing
this manuscript.


REFERENCES CITED

CARLSON, D. A., AND S. R. YOCOM. 1986. Cuticular hydrocarbons from six species of
fruit flies. Arch. Ins. Biochem. Physiol. 3: 397-412.
CLARK, R. A., AND H. V. WEEMS, JR. 1989. Detection, quarantine, and eradication of
fruit flies invading Florida. Proc. Florida State Hort. Soc. 102: 159-164.
HARDY, D. E. 1949. Studies in Hawaiian fruit flies. Proc. Entomol. Soc. Washington
51: 181-205.
HEPPNER, J. B. 1984. Larvae of fruit flies. I. Anastrepha ludens (Mexican fruit fly)
and Anastrepha suspense (Caribbean fruit fly) (Diptera: Tephritidae). Ento
mol. Circ. 260. Florida Dept. Agric. & Cons. Serv.
KOVATS, E. 1965. Gas chromatographic characterization of organic substances in the
retention index system. Adv. Chromatogr. 1: 229-247.
PHILLIPS, V. T. 1946. The biology and identification of trypetid larvae (Diptera: Try
petidae). American Entomol. Soc. Mem. 12, 161 pp.
RIHERD, C. 1993. Citrus production areas maintained free of Caribbean Fruit Fly for
export certification, pp. 407-413 in M. Aluja and P. Liedo [eds], Fruit Flies: Bi
ology and Management. NY: Springer-Verlag.
SILVERMAN, B. W. 1986. Density Estimation for Statistics and Data Analysis. Lon
don: Chapman and Hall, 175 pp.
STECK, G. J., L. E. CARROLL, H. CELEDONIO-HURTADO, AND J. GUILLEN-AQUILAR.
1990. Methods for identification of Anastrepha larvae (Diptera: Tephritidae),
and key to 13 species. Proc. Entomol. Soc. Washington 92: 333-346.
SUTTON, B. D., AND D. A. CARLSON. 1993. Interspecific variation in tephritid fruit fly
larval surface hydrocarbons. Arch. Insect Biochem. Physiol. 23: 5365.


444444444444444444444444444444444444444, A A A A A A A A A A A A A A A A A A A






Mitchell & Tumlinson: Response to Pheromone


RESPONSE OF SPODOPTERA EXIGUA AND S. ERIDANIA
(LEPIDOPTERA: NOCTUIDAE) MALES TO SYNTHETIC
PHEROMONE AND S. EXIGUA FEMALES1


EVERETT R. MITCHELL AND JAMES H. TUMLINSON
Insect Attractants, Behavior, and Basic Biology
Research Laboratory, Agricultural Research Service
U.S. Department of Agriculture, Gainesville, FL 32604

ABSTRACT

The seasonal occurrence of the beet armyworm, Spodoptera exigua (Hiibner), and
the southern armyworm, Spodoptera eridania (Cramer), was monitored over a 2
year period using International Pheromones, Ltd. Moth Traps baited with rubber
septa impregnated with pheromone blends identified from conspecific females and
also with pheromone emitted by live female beet armyworm moths. The pheromone
blend for beet armyworm was (Z)-9-tetradecen-l ol (2.5%), (Z,E)-9,12-tetradecadien

1This article reports the results of research only Mention of a proprietary product does not constitute an en
dorsement or the recommendation of its use by USDA.

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. O. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
1tus document was created with rameMaker 4.0.2






Florida Entomologist 77(2)


1-ol acetate (87.2%), and (Z)-11-hexadecen-1-ol acetate (10.3%). The pheromone
blend used for southern armyworm was (Z)-9-tetradecen 1 ol acetate (55.78%), (Z,E)
9,12-tetradecadien-1-ol acetate (21.23%), (Z,E)-9,11 tetradecadien-1-ol acetate
(8.67%), and (Z)-11-hexadecen-1-ol acetate (14.32%). Although subtropical in habit,
both species apparently can survive in North-Central Florida even when tempera
tures drop below freezing for several days. The response of male southern armyworm
moths to traps baited with beet armyworm females was remarkably similar to that
recorded for southern armyworm males to their synthetic pheromone. This response
was consistent over two years.
Key Words: Cross sex attraction, southern armyworm, beet armyworm, (Z)-9-tet
radecen-1-ol, (Z,E)-9,12-tetradecadien-1-ol acetate, (Z,E)-9,11 tetradecadien-1-ol ac
etate, (Z)-11-hexadecen-1-ol acetate.

RESUME

La dinamica poblacional del trozador de la remolacha, Spodoptera exigua (Hob-
ner), y del trozador sureno Spodoptera eridania (Cramer), fue estudiada durante 2
anos, al usar trampas con feromonas de polillas de la compania International Pher
omones. El cebo utilizado consisti6 en un tabique de caucho impregnado con mezclas
de feromonas de hembras conespecificas y con feromonas provenientes de hembras
de la polilla de la remolacha. La mezcla de feromona para la polilla de la remolacha
fue (Z)-9-tetradecen 1 ol (2.5%), (Z,E)-9,12 tetradecadien 1 ol acetato (87.2%), y
(Z) 11 hexadecen 1 ol acetato (10.3%). La mezcla de feromona para el trozador S. eri
dania fue (Z)-9-tetradecen 1 ol acetato (55.78%), (Z,E)-9,12 tetradecadien 1 ol ace
tato (21.23%), (Z,E)-9,11 tetradecadien-1-ol acetato (8.67%), y (Z)-11-hexadecen-1-ol
acetato (14.32%). Aunque ambas species son subtropicales, ellas pueden sobrevivir
en la parte central y norte de Florida, aun en aquellos dias en que la temperature es
bajo zero. La respuesta de las polillas del trozador sureno alas trampas con hembras
de polilla de la remolacha fue muy similar a aquellas trampas con feromona sintetica
de su misma especie. Esta respuesta fue consistent durante dos anos.



Members of the genus Spodoptera are distributed throughout the world and in
clude a number of species that cause significant economic damage to agricultural
crops. The beet armyworm (BAW), S. exigua (Htibner), and southern armyworm
(SAW), S. eridania (Cramer), are two of three major North American pests in this ge
nus. Both the BAW and SAW are present in much of Florida throughout the year
where they often cause considerable economic damage on commercial vegetable
crops. In recent years, the BAW also has become a threat to cotton production in the
southeastern U.S. The SAW also has demonstrated a propensity to broaden its host
range and include sunflower, often defoliating plants to a degree that yields are
greatly reduced (Mitchell 1984).
Growers in North-Central Florida are experimenting with alternate crops such as
cotton, sunflower, and vegetables to replace declining acreages of tobacco and field
corn. Not only are growers planting replacement crops, but they also are investigate
ing ways of intensifying production using double-cropping practices. For example,
some growers are following spring planted corn grown for silage with cotton planted
in mid-summer; still others are following winter vegetables, such as cabbage, with
plantings of sorghum or corn in late spring or early summer.
The changing cultural practices have heightened grower awareness of possible
shifts in insect pest complexes, especially if plant hosts and suitable habitats become
available throughout most of the year. Although subtropical in habit, both the BAW
and SAW are potential threats to most of the crops undergoing evaluation by North
Central Florida growers. Therefore, traps baited with synthetic sex pheromone and


June, 1994






Mitchell & Tumlinson: Response to Pheromone


live BAW female moths were used to monitor the seasonal occurrence of BAW and
SAW in this area over a 2-year period beginning in fall 1988.
The synthetic pheromone blend used to monitor the BAW was identified by Tum
linson et al. (1990). They detected and identified five compounds from the volatiles
emitted by virgin BAW females: (Z)-9-tetradecen 1 ol acetate; (Z)-9-tetradecen-l ol;
(Z,E)-9,12-tetradecadien-1-ol acetate; (Z,Z)-9,12-tetradecadien-1-ol acetate; and (Z)
11-hexadecen 1 ol acetate in a ratio of 47.9:4.0:40.2:6.5:1.7, respectively. Field tests
of these components in various formulations on rubber septa using bucket traps in
dicated that a blend of (Z)-9-tetradecenol, (Z,E)-9,12-tetradecadien 1 ol acetate, and
(Z)-11-hexadecen-1-ol acetate was most effective for trapping BAW males and that
(Z)-9-tetradecen-l-ol acetate actually decreased trap captures. Blends that did not
contain both (Z)-9-tetradecen 1 ol and (Z,E)-9,12-tetradecadien 1 ol acetate were in
effective as trap baits (Tumlinson et al. 1990).
Analysis of sex pheromone glands and volatile pheromone components collected
from calling female SAW indicated that a number of 14-carbon mono and di-unsat
rated acetates and a mono-unsaturated 16-carbon acetate were produced and re
leased (Teal et al. 1985). In the same study, the results of field trapping experiments
indicated that a blend of (Z)-9-tetradecen-l-ol acetate (Z9-14:AC), (Z,E)-9,12-tet
radecadien 1 ol acetate (Z9,E12 14:AC), (Z,Z)-9,12 tetradecadien 1 ol acetate
(Z9,Z12-14:AC), (Z,E)-9,11 tetradecadien-1-ol acetate (Z9,E11-14:AC), and (Z)-11
hexadecen-1-ol acetate (Z11-16:AC) was an effective lure for SAW males capturing
significantly greater numbers of moths than did female-baited traps. Of these five
components, only Z9,Z12-14:AC did not appear to affect trap capture significantly.
Gland extracts also indicated the presence of (Z)-9-tetradecen-l ol (Z9-14:OH), but
this compound was not found in volatiles emitted by females (Teal et al. 1985).

MATERIALS AND METHODS

The study was conducted over a period of 34 months from October 1988 through
June 1991. International Pheromones, Ltd. Moth Traps (i.e., bucket traps), of the
type previously used in field evaluations of the pheromone components emitted by
calling virgin BAW female moths (Tumlinson et al. 1990), were set out in northwest
Alachua County, Florida. Two traps were placed about 1 m above the ground on
metal poles at each of three different locations adjacent to cultivated (field corn) and
fallowed fields. The distance between traps at each location was about 100 m, and
the distance between locations was about 1 km. One of the two traps at each location
was baited with four virgin BAW females (2-3 days old). The second trap was baited
with a 5 x 9 mm rubber septum (A. H. Thomas Co.) treated with a 100 pl hexane so
lution containing 200 tg of a pheromone blend previously identified from BAW fe
males: (Z)-9-tetradecen 1 ol (2.5%), (Z,E)-9,12-tetradecadien 1 ol acetate (87.2%),
and (Z)-11-hexadecen-1-ol acetate (10.3%) (Tumlinson et al. 1990).
In June 1989, a third bucket trap baited with synthetic SAW pheromone was
added to each location and positioned as described for the traps containing the BAW
females and BAW septum. The SAW septum was treated with a 100 pl hexane solu
tion containing 200 ag of a pheromone blend previously identified from SAW females:
(Z)-9-tetradecen- 1 -ol acetate (55.78%), (Z,E)-9,12-tetradecadien 1 ol acetate
(21.23%), (Z,E)-9,11 tetradecadien- 1ol acetate (8.67%), and (Z) 11-hexadecen-1-ol
acetate (14.32%) (Teal et al. 1985). No SAW females were available for comparative
studies with the synthetic pheromone blend.
Septa were Soxhlet-extracted with methylene chloride for 24 h and air dried be
fore loading. The percentage of each component in the pheromone blend loaded onto
septa was calculated on the basis of its relative volatility. This was determined from
retention indices on liquid crystal capillary GC columns (Heath & Tumlinson 1986)







Florida Entomologist 77(2)


by a method developed to predict release ratios of components of a blend from rubber
septa (Heath et al. 1986).
A Vapona insecticide strip (Vaportape II, Hercon Environmental Company,
Emigsville, PA) was placed inside the buckets as a killing agent for trapped moths.
The traps were checked 1-3 times per week depending upon the season. During win
ter (December-February), the traps were checked and rotated between positions
weekly. The rest of the year, the traps were checked and rotated on monday, wednes
day, and friday of each week. Bait females were replaced at each inspection; the bait
septa and Vaportape II were replaced every two weeks.


RESULTS AND DISCUSSION

Seasonal Response to Pheromone

Captures of BAW in traps baited with rubber septa lures impregnated with the 3
component pheromone blend and virgin BAW females are presented in Fig. 1. Moth
captures were greatest during summer and fall both years. Trap capture peaks and
valleys for both pheromone and female baits were remarkably similar with the syn
thetic lure generally capturing more males during most periods. A total of 3,328
BAW males were captured in traps baited with BAW females in 1988-89 and 5,817
were captured in 1989-90. In the traps baited with septa impregnated with phero
mone, 7,383 males were captured in 1988-89 and 9,354 were captured in 1989-90.
Captures of SAW in traps baited with rubber septa impregnated with synthetic
pheromone are shown in Fig. 2. Moth captures were greatest during summer and fall
as for the BAW. A total of 2,611 SAW males were captured during 1989-1990 and
1,558 were captured during 1990-1991.
The apparent growth in populations of both BAW and SAW, as indicated by the
number of moths captured from July through October, was comparatively more uni
form during 1990. Although the number of BAW and SAW males captured in phero
mone-baited traps during this period were similar to the numbers captured during
the same period in 1989, BAW and SAW populations appeared to start increasing
about two weeks later in 1990 than in 1989.
The steady growth of BAW and SAW moth captures in fall of 1990 likely was due
to weather conditions that were conducive to growth of wild hosts common to this
area of Florida, especially Amaranthus spp. Based upon weather data compiled by
the Agronomy Department, IFAS, University of Florida, Gainesville, drought condi
tions prevailed throughout Florida from January 1989 through June 1990. During
this period, the monthly rainfall deficit, i.e., deviation from expected rainfall, aver
aged 14.09 cm with a range of 28.21 cm in May 1989 to 0.86 cm in June 1990. The
drought was broken in July 1990 and followed by near normal levels of rainfall
through November 1990. December 1990 was very dry; the rainfall deficit was 5.38
cm below the normal rainfall level of 8.10 cm for the month.
Numbers of BAW and SAW captured in spring and early summer 1991 tended to
be lower than numbers captured in the same period of 1990. Again, this probably was
due to the level of rainfall received. Unlike spring 1990, which was unusually dry,
1991 was marked by abnormally high levels of rainfall. From January through July
1991, rainfall averaged 17.98 cm above normal, ranging from +0.33 cm in February
to +26.41 cm in July. The torrential rains that often occurred during this period pos
sibly helped keep the armyworm populations low, by destroying young larvae soon
after they hatched, and also by increasing the level of natural control via disease or
ganisms.
Both BAW and SAW are subtropical species that cannot diapause and thus are
unable to survive during extended periods of near or sub-freezing temperatures.
The species' overwintering range appears to be governed by the occurrence of frost


June, 1994






Mitchell & Tumlinson: Response to Pheromone


2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0




2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0


11 8 6 3 6 7 4 2 5 3 7 5 2
O N D J F M A M J J A S O


10 6 4 2 5 4 2 7 4 2 6 4 1
O N D J F M A M J J A S O
Fig. 1. Weekly captures of male beet armyworm moths in bucket traps baited with
rubber septa lures treated with synthetic sex pheromone simulating conspecific fe
males and beet armyworm females. Numbers above months are reference dates for
beginning of weekly periods. October 1988-September 1990. Alachua County, Florida.





Florida Entomologist 77(2)


1.0

0.8

0.6

0.4

0.2

0.0


1.0

0.8

0.6

0.4

0.2

0.0


9 6 4 1 5 3 7 4 4 1 3 7 5
J A S O N D J F MA M J J


9 6 4 1 5 3 7 4 4 1 3 7 5
J A S 0 N D J F MA M J J
Fig. 2. Weekly captures of male southern armyworm moths in bucket traps baited
with rubber septa lures treated with synthetic sex pheromone simulating conspecific
females and with natural sex pheromone emitted by beet armyworm females. Num-
bers above months are reference dates for beginning of weekly periods. July 1989
June 1991. Alachua County, Florida.


June, 1994







Mitchell & Tumlinson: Response to Pheromone


that kills host plants and by prolonged temperatures below about 10'C. Thus, the
BAW and SAW are very similar in habit, overwintering by continuous generations in
subtropical areas of Florida and Texas, and in a few areas along the Gulf Coast
(Mitchell 1979). Both species appear to disperse from these areas into more temper
ate zones of the United States each spring and summer.
The data on moth captures for the winter of 1989-1990 and 1990-1991 present
paradoxical situations relative to survival of BAW and SAW in North-Central Flor
ida. Three days of continuous sub-freezing temperatures were recorded in this area
during late December 1989, with snow and ice recorded on the 23rd and 24th. Depar
tures from the normal maximum, minimum and average temperature for December
were 230, 23.70, and 23.40 C., respectively
The effect of the unusually cold temperatures was reflected in zero moth captures
in traps baited with BAW females and synthetic SAW pheromone, respectively, dur
ing the last two weeks of December 1989 and the first week of January 1990. Never
theless, a few BAW and SAW males were captured early in January 1990, and
captures of both species continued into spring. These results suggest that the BAW
and SAW possibly survived winter in North-Central Florida even under the rather
extreme conditions of below freezing temperatures. Of course, the possibility that the
insects captured during this period were migrants cannot be discounted completely.
In contrast to winter 1989-1990, the winter of 1990-1991 was extremely mild, al
lowing continuous growth of herbaceous species that normally would have been
killed by frost. These conditions probably allowed for reproduction by BAW and SAW
later in fall 1990; hence, accounting for possible local emergence of the moths cap
tured during December 1990-January 1991. Comparative data on capture of BAW in
traps baited with synthetic pheromone in the same period are not available because
these traps were discontinued in October 1990.


Cross Sex Attraction

Mitchell & Doolittle (1976) reported cross sex attraction between BAW and SAW.
This intriguing relationship is demonstrated also in these studies (Figs. 2 and 3).
Mitchell and Doolittle used females of each species in Pherocon 1C sticky traps and
about 13% of the moths captured in traps baited with BAW females were SAW males.
Conversely, about 8% of the males captured in traps baited with SAW females were
BAW males.
In the present study, a total of 8,420 BAW males were captured in traps baited
with BAW females from July 1989 through June 1991 (2,742 in 1989-1990 and 5,678
in 1990-1991). A total of 2,019 SAW males also were captured in the same traps
(1,253 in 1989-1990 and 766 in 1990-1991).
A total of 4,169 SAW males were captured in traps baited with lures treated with
synthetic SAW sex pheromone. However, no BAW males were captured in any of
these traps over the course of the two-year survey. Interestingly, the percentage of
SAW males captured in traps baited with BAW females equaled 48.4% of the number
of SAW males captured in traps baited with synthetic SAW sex pheromone.
The pattern of capture of SAW males in traps baited with BAW females paralleled
closely the capture of SAW in traps baited with synthetic SAW sex pheromone (Fig.
2). The results of regression analysis of the number of SAW males captured in traps
baited with BAW females versus the numbers captured in traps baited with syn
thetic SAW pheromone are presented in Fig. 3. These results suggest that cross sex
attraction of SAW males to BAW females was consistent and independent of possible
seasonal effects that may have been caused by positioning the traps close to host
plants. Moreover, the capture of SAW males in traps baited with BAW females was
as good an indicator of seasonal occurrence and population peaks of SAW (Fig. 2), as
was the synthetic pheromone blend identified from conspecific females.






Florida Entomologist 77(2)


1.25

1.13

1.00

0.88

0.75

0.63

0.50

0.38 o
: o& 0
0.25 /o
o O
0.13 o0

0.00 o O
0.00 0.13 0.25


--Log (x+1) Mean/trap/night--


0

0
0
o
o
o
/




o


o/




0 o
0

Y-0.059506+1.249561(X)

R-squared-0.87, 51 d.f.





1989-90


0.38 0.50 0.63 0.75 0.88 1.00 1.13 1.25


3 BAW females
1.25

1.13

S 1.00


0 0
0.88

0.75 /0

S 0.83 Y-0.71812+1.217484(X)
C O
S 0.50 U oO R-squared-0.81, 51 d.f.

S 0.38 0

S 0.25

013 0 1990-91

0.00 'f -. I .
0.00 0.13 0.25 0.38 0.50 0.83 0.75 0.88 1.00 1.13 1.25

3 BAW females

Fig. 3. Relationship between the number of male southern armyworm moths cap
tured in traps baited with beet armyworm females and numbers captured in bucket
traps baited with synthetic sex pheromone simulating pheromone produced by south
ern armyworm females.


June, 1994







Mitchell & Tumlinson: Response to Pheromone


The reason for attraction of SAW males to BAW females is indeed puzzling. How
ever, the chemical composition of the sex pheromone blend volatized by the two spe
cies may partially explain the unusual cross attraction reported here.
The BAW and SAW have four chemicals in common in their pheromone blend
(Table 1). Of these, (Z)-9-tetradecen 1 ol acetate is the major component volatized by
females of both species; it is a critical component for attraction of SAW males (Teal et
al. 1985) but not for BAW (Tumlinson et al. 1990).The role of (Z)-9-tetradecen 1 ol ac
etate in the sexual behavior of BAW is unknown; but, addition of this compound to
the attractive pheromone blend (Table 1) actually decreases capture of BAW males.
Interestingly, (Z)-9-tetradecen 1 ol was not found among the chemicals volatized
by calling SAW females (Teal et al. 1985), but it was found in gland extracts from
SAW females. It is possible, of course, that (Z)-9-tetradecen 1 ol was emitted by SAW
females but escaped detection because it occurs in such minute quantities. This com
ponent is essential to attraction of BAW males (Tumlinson et al. 1990), and it is vol
atized by BAW females. When Teal et al. (1985) added (Z)-9-tetradecen-l ol to the
SAW pheromone blend, trap captures of SAW were not affected.
In an earlier study, Mitchell (1976) found no evidence of cross mating among
these species in the laboratory. Thus, it is unlikely that SAW males would mate with
BAW females in nature even when attracted to them. Perhaps (Z)-9-tetradecen-l ol
acts as a reproductive isolating mechanism for BAW and SAW during close range
courtship encounters.
The design of the bucket trap used in this study is such that the insects captured
must come within a few centimeters of the lure. Observations on the response of
other noctuid species, namely S. frugiperda (J. E. Smith) and Anticarsia gemmatalis
Hilbner, to synthetic sex pheromone lures in bucket traps indicated that the male
moths became very excited when in close proximity to the bait source. Generally, the
frenzied moths tumbled into the bucket receptacle after 'bumping' into the wall of
the open funnel immediately beneath the lure. Therefore, it is probable that chemi
cals other than those previously identified from females of the BAW and SAW are re
sponsible for their reproductive isolation in nature.



TABLE 1. VOLATILE PHEROMONE COMPONENTS EMITTED BY FEMALES OF SPODOPTERA
EXIGUA (BAW) AND S. ERIDANIA (SAW). A (+) INDICATES THE COMPONENT
IS NECESSARY IN THE PHEROMONE BLEND FOR CAPTURING CONSPECIFIC
MALES IN NUMBERS = OR > THAN THE NUMBERS CAPTURED IN THE SAME
TYPE OF TRAP BAITED WITH VIRGIN FEMALES OF THE SAME SPECIES. ADDI
TION OF THE COMPONENT INDICATED BY (*) TO THE PHEROMONE BLEND RE
SULTED IN CAPTURE OF BAW MALES. ADDITION OF THE COMPONENT
INDICATED BY (!) TO THE PHEROMONE BLEND DIMINISHED CAPTURE OF
BAW MALES.

Chemical' BAW SAW3
Z9,E12 14:AC (+) (40.2) (+) (16.9)
Z9,Z12-14:AC (6.50) (15.2)
Z9,E1114:AC (+) (4.60)
Z9-14:OH (+) (4.00) (*)
Z9-14:AC (!) (47.9) (+) (60.6)
Z11-16:AC (+) (1.70) (+) (2.70)
1 See text for explanation of chemical abbreviations.
2Tumlinson et al. 1990.
3Teal et al. 1985.
4Numbers in 0 are release ratios [%] of pheromone components volatized by calling females. Load ratios used
to achieve the desired release ratios when applied on rubber septa used as lures in bucket traps for SAW were:
Z9,E12-14:AC, 21.23%; Z9,E11-14:AC, 8.67%; Z9-14:AC, 55.78%; and Zll-16:AC, 14.32%.







Florida Entomologist 77(2)


CONCLUSIONS

Synthetic pheromone lures for the BAW were as reliable an indicator of seasonal
occurrence as were virgin BAW females. Although trap catches with the synthetic
blend are well-correlated with live females, this does not necessarily mean that the
catches with either of these lures is well-correlated with actual population densities
in any given field. Indeed, the senior author often has recorded large captures of
these species as well as others including S. frugiperda (J. E. Smith), Heliothis vire
scens (Fabricius), and Helicoverpa zea (Boddie), in traps baited with synthetic pher
omone; but the trap catches usually did not reflect population densities based upon
actual egg, larval, or adult counts in crops such as cotton, corn, and sorghum (unpub
lished).
Although pheromone release rates from septa are influenced by temperature,
there was no indication that the cooler temperatures of winter and spring or the hot,
humid conditions of summer in North-Central Florida had any more influence on
capture of BAW in traps baited with synthetic pheromone than captures in similar
traps baited with virgin BAW females. Indeed, the economy of labor, ease of han
dling, and consistency of delivering a precise quantity of a pheromone at a relatively
modest cost, compared with rearing and maintaining live insect baits and the confi
dence that the results obtained with synthetic lures are as meaningful as those ob
trained with live insects, warrants the continued use of synthetic pheromone for long
term monitoring of BAW.
Also, the synthetic sex pheromone lure used for the SAW appeared to provide a
realistic picture of the seasonal occurrence and shifts in population numbers of this
pest. Although SAW female baits were not available for comparison with the syn
thetic lure, it is not unreasonable to assume that a comparative study would have
yielded results similar to those recorded for the BAW.
Captures of SAW males in traps baited with BAW females presented as accurate
an assessment of its seasonal occurrence as was defined by captures of SAW males in
traps baited with synthetic SAW pheromone. As desirable as such a dual monitoring
scheme may be, the use of BAW females to monitor SAW populations is unrealistic.
As demonstrated here, synthetic BAW pheromone, not BAW females, is the bait of
choice for monitoring this pest. Unfortunately, SAW males are not captured in traps
baited with synthetic BAW pheromone.


ACKNOWLEDGMENT

We gratefully acknowledge the technical assistance of P. Brennan for preparing
the bait septa, W Copeland for collecting the trap data, and J. Leach for preparation
of the graphic material.


REFERENCES CITED

HEATH, R. R., AND J. H. TUMLINSON. 1986. Correlation of retention times on a liquid
crystal capillary column with reported vapor pressures and half lives of com
pounds used in pheromone formulations. J. Chem. Ecol. 12: 2081-2088.
HEATH, R. R., P. E. A. TEAL, J. H. TUMLINSON, AND L. J. MENGELKOCH. 1986. Predic
tion of release of multicomponent pheromone blends from rubber septa. J.
Chem. Ecol. 12: 2133-2143.
MITCHELL, E. R. 1976. Mating specificity in Spodoptera spp. Florida Entomol. 59:
416.
MITCHELL, E. R. 1979. Migration by Spodoptera exigua and S. frugiperda, North
American style, pp. 386-393 in R. L. Rabb and G. G. Kennedy [eds.] Movement
of highly mobile insects: concepts and methodology in research. University
Graphics, North Carolina State University, Raleigh.


June, 1994






Giblin-Davis et al: Trapping ofMetamasius hemipterus 247


MITCHELL, E. R. 1984. Damage of sunflower by the southern armyworm (Lepi
doptera: Noctuidae). Florida Entomol. 67: 273-277.
MITCHELL, E. R., AND R. E. DOOLITTLE. 1976. Sex pheromones of Spodoptera exigua,
S. eridania, and S. frugiperda: Bioassay for field activity. J. Econ. Entomol. 69:
324-326.
TEAL, P. E. A., E. R. MITCHELL, H. H. TUMLINSON, R. R. HEATH, AND H. SUGIE. 1985.
Identification of volatile sex pheromone components released by the southern
armyworm, Spodoptera eridania (Cramer). J. Chem. Ecol. 6: 717-725.
TUMLINSON, J. H., E. R. MITCHELL, AND H. S. Yu. 1990. Analysis and field evalua
tion of volatile blend emitted by calling virgin females of beet armyworm,
Spodoptera exigua (Hibner). J. Chem. Ecol. 16: 3411-3423.






Giblin-Davis et al.: Trapping ofMetamasius hemipterus


LETHAL PITFALL TRAP FOR EVALUATION OF
SEMIOCHEMICAL-MEDIATED ATTRACTION OF
METAMASIUS HEMIPTERUS SERICEUS
(COLEOPTERA: CURCULIONIDAE)

ROBIN M. GIBLIN-DAVIS,1 JORGE E. PENA,2 AND RITA E. DUNCAN1
1Fort Lauderdale Research and Education Center
University of Florida, IFAS
3205 College Avenue, Fort Lauderdale, FL 33314

2Tropical Research and Education Center
University of Florida, IFAS
18905 S. W. 280 Street, Homestead, FL 33031


ABSTRACT

A lethal pitfall trap was developed for evaluating field response of adults of the
West Indian sugarcane borer, Metamasius hemipterus sericeus (Olivier), to semio
chemical attractants. Using this trap, we determined that early (< 5 days) volatile
fermentation products from 250 g of chopped fresh stem tissue from the cabbage pal
metto (Sabal palmetto [Walter]), sugarcane (Saccharum officinarum L.), pineapple
(Anana comosus [L.]), or pseudostem from banana (Musa sp.) (fermented under wa
ter for 5-7 days) were attractive to M. h. sericeus adults in the field. Weevils were not
trapped with fresh banana pseudostem and chopped unfurled leaves of S. palmetto.
The addition of 20 males or 20 females to 250 g of chopped S. palmetto stem tissue in
creased capture of M. h. sericeus over tissue alone. Surveys with the lethal pitfall
trap baited with sugarcane tissue demonstrated that M. h. sericeus is established in
Dade, Broward, and Palm Beach Counties, Florida. This weevil poses a potential
threat to sugarcane and field plantings of certain ornamental palm species, include
ing Hyophorbe verschaffeltii Wendland, Phoenix canariensis Hortorum ex Chabaud,
Ptychosperma macarthurii (Wendland), Ravenea rivularis, Roystonea regia (Hum
bolt, Bonpland & Kunth), and Washingtonia robusta Wendland.

RESUME

Se evalu6 en el campo la atracci6n de adults del picudo de la cana podrida, Meta
masius hemipterus sericeus (Oliver) a atrayentes quimicos colocados en una trampa
letal. Los primeros products volatiles (< 5 dias) emanados de la fermentaci6n de 250
g de tejido fresco picado de palmeto de col (Sabalpalmetto [Walter]), cana de azticar
(Saccharum officinarum L.), pina (Anana comosus [L.]) o pseudotallo de banano
(Musa sp.) (fermentado en agua por 5-7 dias), fueron atractivos a los adults de M. h.

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. 0. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
This docuumiil was clae~td will F7aMiklakel 4.0.2p .






Florida Entomologist 77(2)


sericeus en el campo. El pseudotallo de banano y las hojas picadas del cogollo de S.
palmetto no atrayeron adults del picudo. La capture de M. h. sericeus aument6 al
adicionar 20 machos o 20 hembras a una trampa con 250 g de tallo picado de S. pal
meto en comparaci6n con el tallo picado solo. El uso de la trampa letal demostr6 que
M. h. sericeus esta establecido en Florida en los condados de Dade, Broward y Palm
Beach, Florida y present una amenaza potential a la cana de azucar y a ciertas es
species de palmas ornamentales, tales como Hyophorbe verschaffeltii Wendland,
Phoenix canariensis Hortorum ex Chabaud, Ptychosperma macarthurii (Wendland),
Ravenia rivularis, Roystonia regia (Humboldt, Bonpland & Kunth), y Washingtonia
robusta Wendland.



The West Indian sugarcane borer, Metamasius hemipterus (L.) is an economically
important pest of sugarcane and other tropical plants in the Neotropics (Raigosa
1974, Vaurie 1966). There are three recognized subspecies of this weevil; M. h. hem
ipterus (L.) is distributed southwards from Puerto Rico through the Lesser Antilles
and into most of South America; M. h. sericeus (Olivier) is found in the Greater Anti
lles and Central America south from Nicaragua to western Colombia and Ecuador;
while M. h. carbonarius (Chevrolat) occurs from Mexico south to El Salvador and
Honduras (Vaurie 1966). Metamasius hemipterus sericeus first became established in
Dade Co., Florida in about 1984 (Woodruff & Baranowski 1985).
The biology of all three subspecies is very similar. Adult weevils are attracted to,
and oviposit in, damaged or stressed sugarcane stalks, banana pseudostems, ripe
fruit (i.e. pineapple, mango, papaya), or palm sheaths or stems (Vaurie 1966) where
the larvae develop to adults in less than 2 months (Woodruff & Baranowski 1985).
Wolcott (1955) reported that the female weevil oviposits in damaged sugarcane stem
but that the larvae tunnel into healthy tissue causing it to ferment.
Fermenting sugarcane tissue has been used to attract M. hemipterus (Raigosa
1974) and M. anceps (Gyllenhal) (Teran 1968) in the field. Also, a yeast, water, and
molasses mixture applied to sugarcane bagasse in single open-ended bamboo cylin
der traps was used to attract M. hemipterus in Colombia (Arango & Rizo 1977). In all
of these cases, the bait was poisoned with an insecticide to kill the weevils. Six times
more M. hemipterus were attracted to sugarcane soaked for 12-24 hrs in water than
to sugarcane soaked in 0.1% parathion and placed in traps made of 30-40 cm long cyl
inders of bamboo with a single open end (Raigosa 1974). The use of a lethal trap is
critical for evaluation of semiochemicals, especially when pheromones are suspected.
The use of insecticides can be very effective for field trapping and study of the chem
ical ecology of weevils (Oehlschlager et al. 1992). However, the attractancy or repel
lency of the insecticide to the target organism must be evaluated and safety
precautions must be followed in trap set-up, placement, and maintenance. A safe and
effective trap for evaluating semiochemical attractants for the subspecies of M hem
ipterus is needed.
Males of many species of weevils produce aggregation pheromones which can be
useful for monitoring the movement of pests, mass trapping, or for timing applica
tions of pesticides or biologicals (Weissling et al. 1994). Increasing our knowledge of
semiochemical attractants for M. h. sericeus is important because they would be ex
tremely useful for monitoring weevil movement into the southeastern U.S.A. and for
developing biorational approaches for their management in Florida.
The purpose of this study was twofold: (1) to develop a safe, lethal trap to
field-evaluate the attraction of semiochemicals to M. h. sericeus adults and (2) to use
this trap to evaluate the attraction of different fermenting plant tissues alone, and
with or without conspecifics, to M. h. sericeus adults in the field. During this study
we also demonstrated that this weevil is newly established in two counties in south
eastern Florida. Symptoms of M. h. sericeus infestations in field-grown palm plant
ings were observed and are described herein.


June, 1994






Giblin-Davis et al: Trapping ofMetamasius hemipterus 249


MATERIALS AND METHODS

Lethal Trap Design

The lethal pitfall trap that was developed consisted of two translucent white,
high density polyethylene (HDPE) plastic tapered containers (Fisher Scientific Co.,
Pittsburgh, PA), one 4.9 liters and the other 0.946 liters in size (Fig. 1). Soapy water
in the bottom of the larger container acted as the lethal agent. Four 3-mm diam
drainage holes were drilled at 90 from each other in the sides of the 4.9-liter bucket,
6 cm from the bottom. The 0.946 liter container, which was used to hold the attrac
tant, had 2 rows of 9 ventilation holes drilled in its sides near the bottom (Fig. Ib). An
8.5-cm diam hole was cut in the lid of this container and a 9.5-cm diam piece of alu
minum screening (1.5-mm square openings) was glued to the inside of the lid to cover
this hole. The lid was needed to retain the attractant (250 g of chopped test tissue
and/or adult weevils) within the container when it was inverted inside the larger
container (Fig. Ib). It was suspended in this container on a vinyl clad steel wire (32
cm in length) which was threaded through 3-mm holes at 180 from each other 1 cm
below the top opening in the 4.9-liter bucket and through the bottom (now top) of the
inverted bait container. It was suspended concentrically in the mouth of the bucket
(Fig. la,b). Each assembled trap was buried to within about 2.5 cm of the trap top in
the shade of a mature banana plant and filled with about 600 ml of soapy water (10
g Alconox soap [Alconox, Inc., New York, NY] per liter water).
In a preliminary study, this trap design was baited with 250 g of banana (Musa
sp.) pseudostem (fermented under water for 5-7 days) and compared with the follow
ing six designs: 1) the above design set on the soil surface, 2) a fermented banana
pseudostem sandwich trap (Mitchell 1978) with two slices of pseudostem (total about


Plant_
material (top view)


Container I-
S(side view) "


4,
,, ;-'


Os


Fig. 1. Lethal pitfall trap used to capture and kill adults of Metamasius hem
ipterus sericeus attracted to different fermenting plant tissues and/or conspecifics: (a)
assembled, (b) unassembled.


I ;






Florida Entomologist 77(2)


550 g of tissue) bound together with a rubber band and placed on the ground, 3) a live
Rhynchophorus cruentatus (F) trap (Weissling et al. 1992) placed on the ground with
1.3 kg of fermented banana pseudostem, 4) a lethal R. cruentatus trap (Weissling et
al. 1993) set on the ground, with and without a polyvinyl chloride composite lid,
baited with 1.3 kg of fermented banana pseudostem, and 5) a 19-liter black plastic
bucket set on the ground and baited with 1.3 kg of fermented banana pseudostem.
There were two replicates for each of the seven designs and traps were set out in a
15.5 ha, 2 year-old banana plantation, located near Homestead, Dade County, FL.
Traps were spaced > 20 m apart in rows of banana plants.


Field Response of Weevils to Fermenting Plant Tissues

Experiment No. 1 was conducted 6-11 January 1993 using the lethal pitfall trap
described previously. The plant tissue attractants were 250 g of chopped tissue from
the following sources: 1) fresh unfurled leaves of Sabal palmetto (Walter), 2) fresh
stems of sugarcane, Saccharum officinarum L., 3) fresh pineapple, Anana comosus
(L.), 4) fresh pseudostem of banana, Musa sp., 5) 7-10 cm-thick cross-sections of ba
nana pseudostem fermented for 5-7 days under water, and 6) no tissue.
Experiment No. 2 was conducted 20-25 January 1993. The treatments were the
same as for experiment No. 1 except that both banana pseudostem treatments were
dropped and fresh S. palmetto stem tissue was added as the fifth treatment.
Traps for both experiments were arranged in a randomized complete block design
in the previously described banana plantation. Treatments were spaced about 20 m
apart in a row of banana plants (block) and blocks were separated by about 20 m (2
or more rows of banana plants). There were seven blocks for experiment No. 1 and
eight for experiment No. 2. Total numbers of adult male and female M. h. sericeus
collected per trap for each 5-day trapping period were used for analysis. Data were
transformed (x + 0.5)0.5 and a Statistical Analysis System general linear models pro
cedure (SAS Institute 1985) for unbalanced ANOVA was used. Untransformed
means are presented. AWaller-Duncan k ratio t-test (k = 100, P< 0.05) was used for
means separation.


Field Response of Weevils to Fermenting Plant Tissues and/or Conspecifics

The lethal pitfall trap (Fig. 1) was used in the field to test the attraction of weevils
to live conspecifics in contact with and without S. palmetto tissue. All traps contained
two water-moistened cellulose sponges. Treatments were traps baited with the fol
lowing: 1) moistened sponges (unbaited control), 2) 20 males of M h. sericeus, 3) 20
females of M. h. sericeus, 4) 250 g of chopped fresh S. palmetto stem tissue, 5) 250 g
of chopped tissue plus 20 male weevils, 6) 250 g of chopped tissue plus 20 female wee
vils, and 7) 250 g of banana pseudostem fermented as previously described. The ex
periment was conducted 2-7 December 1992 (4 replicates) and 9-14 December 1992
(4 replicates) after re-randomization of treatments in a different field location. Ex
perimental design and analysis were as previously described.


Survey of Dade, Broward, and Palm Beach Counties in Florida for
M. h. sericeus and Symptoms

Lethal traps baited with 250 g of chopped sugarcane were used to survey plant
ings of sugarcane, banana, or ornamental palms in Broward (3 sites), Dade (10 sites),
and Palm Beach (8 sites) counties during March-September 1993. Two to seven sur
vey traps were used in each location. Broward, Dade, and Palm Beach county exten
sion units, personnel of the Florida Department of Agriculture and Consumer
Services, Division of Plant Industry, and cooperative growers collaborated with us in


June, 1994







Giblin-Davis et al: Trapping ofMetamasius hemipterus 251


locating active M. h. sericeus infestations and candidate sites for survey and obser
vation of symptoms in host plants.


RESULTS AND DISCUSSION

Lethal Trap Design

In the preliminary study, the lethal pitfall trap (Fig. 1) was 2-17 times more effec
tive for trapping of M. h. sericeus than any of the other designs tested. The mean
counts from the traps tested were; lethal pitfall trap depicted in Fig. 1 (17 weevils),
trap design 1 (2 weevils), trap design 2 (5 weevils), trap design 3 (1 weevil), trap de
sign 4 with pvc lid (9 weevils), trap design 4 without pvc lid (9 weevils), and trap de
sign 5 (1 weevil). The lethal trap is safe, simple, effective, and kills incoming weevils,
thus preventing contact with test attractants or pheromone(s).
This design was used for all of our other experiments. The trap design, color, and
placement will be optimized in future studies when other semiochemical attractants
for M. h. sericeus have been identified.


Field Response of Weevils to Fermenting Plant Tissues

Our study showed that semiochemicals produced by early fermentation (< 5 days)
of a variety of plant tissues were equally attractive to M. h. sericeus. In experiment
No. 1, sugarcane tissue was significantly more attractive to females of M. h. sericeus
(Table 1) than pineapple and fermented banana pseudostem, which were equally at
tractive. Unfurled leaves of S. palmetto, fresh banana pseudostem, and the check
were equally unattractive (Table 1). Sugarcane and pineapple were equally attrac
tive to males of M. h. sericeus. The other tissues were not significantly different from
the check (Table 1). The combined sex ratio for all treatments was about 5.5 females
to 1.0 male.
In experiment No. 2, S. palmetto stem tissue, sugarcane, and pineapple were all
equally attractive to males and females of M. h. sericeus. Unfurled leaves of S. pal
metto and the check were not attractive (Table 1). The sex ratio in experiment No. 2


TABLE 1. ATTRACTION OF METAMASIUS HEMIPTERUS SERICEUS ADULTS TO LETHAL
FIELD TRAPS BAITED WITH DIFFERENT PLANT TISSUES (250 G) IN A BANANA
PLANTATION IN DADE CO., FLORIDA, FOR 5 DAYS.

No. Weevils per Trap (Mean S.E.)'
No. of
Treatments Replicates Females Males
Experiment No. 1 (6 11 January 1993)


Fresh sugarcane stem (chopped) 7 69.6 + 23.6a 11.4 + 3.6a
Fresh pineapple (chopped) 6 25.0 + 15.3b 7.3 + 4.9ab
Fermented banana pseudostem2
(chopped) 7 16.3 + 6.0b 1.3 + 0.7bc
Unpresented Sabal palmetto
leaves (chopped) 7 1.3 + 0.5c 0.4 + 0.3bc
Fresh banana pseudostem
(chopped) 7 0.7 + 0.3c 0.0 + O.Oc
Empty 7 0.0 + O.Oc 0.0 + O.Oc







Florida Entomologist 77(2)


TABLE 1. (CONTINUED) ATTRACTION OF METAMASIUS HEMIPTERUS SERICEUS ADULTS
TO LETHAL FIELD TRAPS BAITED WITH DIFFERENT PLANT TISSUES (250 G) IN
A BANANA PLANTATION IN DADE CO., FLORIDA, FOR 5 DAYS.

No. Weevils per Trap (Mean S.E.)1
No. of
Treatments Replicates Females Males
Experiment No. 2 (20 25 January 1993)


Fresh Sabalpalmetto stem
(chopped) 8 3.8 + 1.5a 25.4 + 12.2a
Fresh sugarcane stem (chopped) 8 2.9 + 2.3ab 18.9 + 6.4a
Fresh pineapple (chopped) 8 1.3 + 0.5ab 15.8 + 7.7a
Unpresented Sabal palmetto
leaves (chopped) 8 0.0 + O.Ob 0.3 + 0.2b
Empty 8 0.0 + O.Ob 0.0 + O.Ob
SI I i I I ...le letter are not significantly different according to aWaller-Duncan kratio ttest
on (x .. i (k= 100, P< 0.05). Untransformed means are presented.
2Fermented as 7-10 cm thick cross-sections under water for 5-7 days.

was reversed from that in experiment No. 1 with about 7.5 males to 1.0 female. The
lack of attractancy of fresh banana pseudostem and unfurled leaves of S. palmetto
may have been caused by a lack of moisture in these tissues. This would have af-
fected the quality of fermentation and the quantity of attractive volatiles released.
Surprisingly, S. palmetto stem tissue was an excellent source of attractive volatiles
even though this palm has not been observed as a host for M. h. sericeus. These data
are consistent with observations that M. h. sericeus is attracted to wounded or fer
meeting tissue of palms, sugarcane, banana, and certain fruits (Vaurie 1966). Cur
rently, we are using gas chromatograph-electroantennograph detection (GC-EAD)
procedures to identify semiochemicals attractive to M. h. sericeus which have been
collected from air perfusions of fermenting S. palmetto, sugarcane, pineapple, and
fermented banana pseudostem. Active chemicals are being evaluated in the field us
ing the lethal pitfall trap.

Field Response of Weevils to Fermenting Plant Tissues and/or Conspecifics

Sabal palmetto tissue plus 20 males and S. palmetto tissue plus 20 females were
equally attractive to females and males of M. h. sericeus and more attractive than S.
palmetto tissue alone (Table 2). Twenty females or 20 males alone, fermented banana
pseudostem alone, and the empty check were all equally not attractive to males and
females (Table 2). Although not statistically significant, male M. h. sericeus in
creased the attractiveness of palm tissue more than females (Table 2).
Our data show that semiochemicals emanating from fermenting tissue of S. pal
metto are attractive by themselves (Table 2). The feeding activity of males or females
on fermenting tissue possibly enhances the release of these volatiles (Table 2). This
has been observed when the pine weevil Hylobius abietis (L.) feeds on pine (Tilles et
al. 1986). These results differ from what has been observed for the palmetto weevil,
Rhynchophorus cruentatus (E). With this species the combination of caged males and
S. palmetto tissue was much more attractive than females and tissue, tissue alone,
males alone, females alone, and the empty check, all of which were about equally un
attractive (Weissling et al. 1993). A male-produced pheromone, 5-methyl-4-octanol
(cruentol), has been identified from R. cruentatus. It has been shown to be ineffective
in field traps when released alone but strongly synergizes the weak attraction of vol
atiles from fermenting plant tissue (Giblin-Davis et al. 1994, Weissling et al. 1994).


June, 1994







Giblin-Davis et al: Trapping ofMetamasius hemipterus 253


TABLE 2. ATTRACTION OF METAMASIUS HEMIPTERUS SERICEUS ADULTS TO LETHAL
FIELD TRAPS BAITED WITH FRESH SABAL PALMETTO OR FERMENTED BA
NANA PSEUDOSTEM TISSUES (250 G) AND/OR LIVE CONSPECIFIC WEEVILS,
OR LEFT UNBAITED IN A BANANA PLANTATION IN DADE CO., FLORIDA FOR 5
DAYS (2-7 AND 9-14 DECEMBER 1992).

No. Weevils per Trap
(Mean S.E.)
No. of
Treatments Replicates Females Males
Fresh S. palmetto stem +
20 6 6 M. hemipterus 8 36.1 + 8.6a 24.6 + 5.8a
Fresh S. palmetto stem +
20 9 M. hemipterus 8 30.8 + 5.4a 17.6 + 3.9a
Fresh S. palmetto stem 8 18.1 + 4.9b 6.0 + 2.3b
Fermented banana pseudostem2 7 3.7 + 1.2c 1.0 + 0.8c
20 6 M. hemipterus 8 0.4 + 0.2c 0.0 + O.Oc
Empty 8 0.0 + O.Oc 0.3 + 0.3c
20 9 M hemipterus 8 0.0 + O.Oc 0.1 + 0.1c
S i I '. .. e letter are not significantly different according to aWaller-Duncan kratio ttest
on (x ," ... I .... i .I (k= 100, P< 0.05). Untransformed means are presented.
2 Fermented as 7-10 cm thick cross sections under water for 5-7 days.


Recently, we collected volatiles from males and females of M. h. sericeus and re
covered eight male-produced chemicals (four GC-EAD-active alcohols and four
GC-EAD-active ketones) (Perez et al. 1994). Using the lethal pitfall trap described
herein (Fig. 1), the four alcohols combined (3-pentanol, 2-methyl-4-heptanol,
2-methyl-4-octanol, and 4-methyl-5-nonanol), each released at 3 mg/day, were as at
tractive as 250 g of sugarcane. When combined, these two treatments showed addi
tive, not synergistic, attraction (Perez et al. 1994). The four GC-EAD-active ketones
of M. h. sericeus males reduced weevil attraction in the field when released with the
GC-EAD-active alcohols plus sugarcane suggesting a role as "spacing" pheromones
(Perez et al. 1994). The lack of a significant difference in attraction between treat
ments of males plus palm tissue and females plus palm tissue in the present study is
not clear. Densities of 20 males of M. h. sericeus may have been too high resulting in
a release of the four GC-EAD-active ketones negating any response to attractive
male-produced semiochemicals.

Survey of Dade, Broward, and Palm Beach Counties in Florida for
M. h. sericeus and Symptoms

Metamasius hemipterus sericeus were trapped near and in banana plantings,
sugarcane fields, and fields of ornamental palms in southern Dade County, and Pa
hokee and Belle Glade, Palm Beach County. We also observed larval infestations for
the first time in damaged sugarcane at the Everglades Research and Education Cen
ter in Belle Glade (1 February 1994). In central and western Broward County, M. h.
sericeus adults were trapped near and in small banana plantings and fields of orna
mental palms.
Larval infestations of M. h. sericeus were noted in palms during 1991-1993 in
Florida as follows: 1) forty healthy (Dade Co.) and about 20 wounded (Dade and Bro
ward Co.) 3 to 4-year-old, field grown spindle palms, Hyophorbe verschaffeltii Wend
land; 2) four 3 to 4-year-old healthy Canary Island date palms, Phoenix canariensis
Hortorum ex Chabaud in Dade Co.; 3) three healthy MacArthur palms, Ptycho
sperma macarthurii (Wendland) in Dade Co.; 4) more than one hundred 3 to







Florida Entomologist 77(2)


4-year-old healthy field grown Majesty palms, Ravenea rivularis in Palm Beach Co.;
5) six 3 to 4-year-old healthy field grown royal palms, Roystonea regia (Humbolt,
Bonpland & Kunth) in Broward and Palm Beach Co.; and 6) two 3 to 4-year-old
healthy Washington fan palms, Washingtonia robusta Wendland in Dade Co.
Metamasius hemipterus sericeus larval tunneling appeared to start in petioles or
wounds in the petioles, crown, or stem and then extends into healthy stem tissue.
Observed symptoms included: 1) the appearance of a dark amber-colored gummy ex
udate which issued from openings to the surface from larval galleries in the stem and
petioles of the crown region or sometimes in the stem near or amongst exposed roots
(R. regia); and 2) open 1.0-1.5 cm diam larval galleries in the leaves, petioles, and
stem. Signs included abandoned cocoons made of stem or petiole fibers, and/or adult,
larval, and pupal weevils at the base of petioles and in galleries in the stem. Overall
symptoms were a lethal wilt with general chlorosis and premature leaf death which
was noticed in all of the P macarthurii, and in several H. verschaffeltii and R. rivu
laris that were examined. Eventually, the crown was completely destroyed and col
lapsed because of larval tunneling. These symptoms are very similar to those caused
in a number of palm species by the cane weevil borer, Rhabdoscelus obscurus (Bois
duval) in Australia (Halfpapp and Storey 1991).
Because the smooth, columnar trunks of H. verschaffeltii, R. rivularis, and R. re
gia are an important part of their aesthetic appeal, even slight damage by M. h. seri
ceus is of economic importance. The W robusta that we examined were booted (with
old petioles attached) and asymptomatic for M. h. sericeus damage until the boots
were removed near the crown revealing typical larval weevil damage. Booted species
of palms would have a higher threshold for aesthetic trunk damage but high densities
of undetected M. h. sericeus might cause stress or kill the tree or provide access for
pathogenic organisms. Palms that are asymptomatic for early M. h. sericeus damage
could escape early visual detection and not be exposed to insecticide treatments in
palm field nurseries. In such cases, a chemically-mediated lethal trap for M. h. seri
ceus would be extremely useful for monitoring, mass-trapping, or pathogen delivery.


ACKNOWLEDGMENTS

We thank M. Stanaland, Z. Alegria, B. Center, J. Cangiamila, and F. G. Bilz for
their technical assistance, J. Perrier for preparation of Figure 1, and R. H. Schef
frahn and F W. Howard for critically reviewing the manuscript. We are grateful to E.
Suarez and P. Naranjo of Homestead, FL, and J. R. and B. Hatton of Pahokee, FL for
allowing us to do field attractancy tests on their respective properties. We thank B.
Coy, D. Clinton, D. Chalot, and M. C. Thomas of the Florida Department of Agricul
ture and Consumer Services, Division of Plant Industry, D. Hull from Dade County
Extension, W. L. Schall from Broward County Extension, and K. Bodman from Red
lands Research Station, Queensland for their help and suggestions. The research
was supported in part by the Dade and Broward County chapters and the State or
ganization of the Florida Nursery Growers Association (FNGA). This manuscript is
Florida Agricultural Experiment Stations Journal Series R-03435.


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June, 1994







Giblin-Davis et al: Trapping ofMetamasius hemipterus 255


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1994. Aggregation pheromones of the sugarcane weevil, Metamasius hem
ipterus sericeus (Olivier). Naturwissenschaften 81: (in press).
RAIGOSA, J. 1974. Nuevos disenos de trampas para control de plagas en cana de
azucar (Saccharum officinarum L.). Memorias II Congreso de la Sociedad de
Entomologia Colombiana, Julio 7 al 10 de 1974, Cali, Colombia. pp. 5-23.
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TERAN, F. 0. 1968. The potential use of insecticide-treated cane pieces to attract and
control adults of the sugarcane weevil, Metamasius bilobus, in Bolivia. J.
Econ. Entomol. 61: 1031-1033.
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G. BERGSTROM. 1986. Increased release of host volatiles from feeding scars: a
major cause of field aggregation in the pine weevil Hylobius abietis (Co
leoptera: Curculionidae). Environ. Entomol. 15: 1050-1054.
VAURIE, P. 1966. A revision of the Neotropical genus Metamasius (Coleoptera, Curcu
lionidae, Rhynchophorinae). Species groups I and II. Bull. American Mus.
Nat. Hist. 131: 213-337.
WEISSLING, T. J., R. M. GIBLINDAVIS, R. H. SCHEFFRAHN, AND N. M.
MARBAN-MENDOZA. 1992. Trap for capturing and retaining Rhynchophorus
cruentatus (Coleoptera: Curculionidae) adults using Sabal palmetto as bait.
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field evidence for male-produced aggregation pheromone in Rhynchophorus
cruentatus (F.) (Coleoptera: Curculionidae). J. Chem. Ecol. 19: 1195 1203.
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JR., AND A. C. OEHLSCHLAGER. 1994. An aggregation pheromone of the pal
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Chem. Ecol. 20: (in press).
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tac. Exp. Agr. Bull. 125: 1208.
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recently established in Florida (Coleoptera: Curculionidae). Florida Dept. Ag
ric. & Consumer Serv. Division of Plant Industry, Entomology Circular No.
272. 4 pp.






Florida Entomologist 77(2)


ADULT SURVIVAL AND MOVEMENT IN MALES OF THE
DAMSELFLY HETAERINA CRUENTATA
(ODONATA: CALOPTERYGIDAE)


ALEJANDRO CORDOBA-AGUILAR
Institute de Ecologia, A. C., Biosistematica de Insectos. Apdo.
Postal 63. Xalapa, Veracruz. 91000 Mexico


ABSTRACT

During a mark-recapture study of the territorial damselfly Hetaerina cruentata
(Rambur), several changes in population size, survivorship and birth rates occurred,
probably caused by physical conditions and a natural seasonal decline in population
size. The average survival rate of males (expected value per day = 0.978) was the
highest reported for the Calopterygidae and possibly all Odonata. This value could
have been affected by factors that reduced energy expenditures at the end of the sea
son. Analysis of male dispersion showed aggregated distributions, which are ex
pected for territorial species. While most males dispersed, no age-class showed a
tendency to move upstream or downstream. Adult females were rare; however, the
sex ratio of nymphs was not significantly different from one.
Key Words: Population size, survivorship, movements, age, males, damselfly

RESUME

Durante un studio de marca-captura de la liblula territorial Hetaerina cruen
tata (Rambur), ocurrieron various cambios en el tamano poblacional, sobrevivencia y
tasas de nacimiento, motivados probablemente por las condiciones fisicas y una dis
minucidn natural del laman6 publacional. La tasa de sobrevivencia masculina (valor
esperado por dia = 0.978) es la mas alta reportada para un Calopterigido y quizas
para todo el orden Odonata. Este valor pudo haber sido afectado por factors que
redujeron los gastos energ6ticos al final de la estacidn. Los analisis de la dispersion
de machos indicaron una distribucidn agregada, lo cual esta de acuerdo con el com-
portamiento territorial de los machos. Apesar de que los machos se dispersaron, nin
guna de las classes de edad mostr6 una tendencia a ir rio arriba o abajo. Aunque las
hembras adults fueron raras, la proporci6n de sexos no fue estadisticamente signif
icativa.



Ecological parameters frequently explain interesting biological variables. Much
of community and population structure is well known today because of the study of
species abundance and composition. Odonates are excellent models in population
ecology, and population studies of some species have been extensive. However, most
studies have been made on temperate species, and our knowledge of tropical species
is still limited (Garrison & Gonzalez-Soriano 1988).
The American genus Hetaerina is widely distributed in tropical areas, and well
studied taxonomically (see Garrison 1990). Nevertheless, diverse aspects of behavior
and ecology in this genus have been poorly described (Johnson 1961, 1962, 1963,
Bick & Sulzbach 1966; also see Alcock 1982 and Eberhard 1986). Considering the
volume of ecological information on other species of odonates, the conspicuousness of
Hetaerina and the suitability of the rivers for study, it is surprising almost no popu
lation data is available except for a few records of H. cruentata biology (e.g. William
son 1923). My aim in this study was to obtain detailed information on the population
biology of a species in this interesting genus. Mark-recapture methods were used to

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. O. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
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June, 1994







Cordoba Aguilar: Survival and Movement in a Damselfly 257


study demographic parameters of a low-density population of the damselfly H. cruen
tata. Data were compared with those of other calopterygids.


MATERIALS AND METHODS

The study was carried out over 21 days (3-24 September, 1992) at the Sordo River
(Fig. 1), which is situated north of Xalapa, Veracruz, Mexico (1930'N, 96 95'W). The
surrounding area is strongly disturbed by agriculture, but some areas still contain
virgin forest vegetation. Other odonates found there were Brechmorhoga vivax Cal
vert (very common), Argia fissa Selys (common), Apanisagrion lais (Selys) (common),
Aeshna psilus Calvert (rare), Remartinia luteipennis florida (Hagen) (rare) and a few
species of Gomphidae (rare).
F. :l. i. -.. 2x2 m quadrats were made along the three branches of the river. An
indelible ink pen was used to write a distinct number, never exceeding three digits,
on either anterior wing. Captures and recaptures were made just once daily, except
on days 7, 9, 12, 13, 22 and 23. Sampling activity started at 0900 and ended at 1200
1230 hours. The following data were recorded for each sighting: individual number,
sex, age, activity, time, quadrat and date.
Individuals were placed into one of three age classes: general, juvenile mature
and old mature. Tenerals were those individuals recently emerged. In general, they
were of soft, fragile construction, difficult to manipulate and flew in a zig-zag pat
tern. Teneral males did not possess the same blackish color as mature adults and the
red spots at the bases of the wings were not intense. In general females, color was not
as distinct as in the other age classes, but the fragility and weak flight was easily
seen. Juvenile mature (JM) animals were identified by their color (principally the
red basal wing spots in males and brilliant greenish body color in females). In old
mature (OM) animals, body color was well developed and the wings were opaque.
Some individuals showed wing damage. A fourth type, mature (M), was frequently
assigned to those individuals in transition between juvenile and old mature. Only
some of the population parameters for females could be obtained because they were
very scarce at the study site.
Jolly's (1965) multiple capture and recapture method was used to estimate the
number of marked animals in the population, population size, survivorship and the
recruitment into the population. Jolly's population survivorship is a relative value
ranging from 0 to 1 (values higher than 1 make no sense). The recruitment estimate
is assumed to be the net increase resulting from birth and migration. Average daily
survivorship (Garrison & Hafernik 1981) was also calculated by averaging daily sur


lm


N\


Fig. 1. Central portion of the study site (Sordo River, Xalapa, Veracruz, Mexico).
Shaded areas are rocks. Points indicate distribution of individuals.







Florida Entomologist 77(2)


vivorship values. Values for missed days between recaptures were estimated as fol
lows (Garrison & Hafernik 1981):

1/d
one day survival rate = (survival rate)

where, dis the number of missed days taking into account the last day of recapture.
The survival rate was translated into expected life-span by the method of Cook et al.
(1967), which according to the average of daily survival rate, indicates a potential ex
pected life-span in the population

-1
expected life-span = 1
loge (average daily survival rate)

Velocity patterns were calculated by Scott's (1974, 1975) procedure to obtain av
erages of total distance travelled in meters (D), time in days (T) and velocity (V=D/T).
Adult velocity is used here as the distance travelled per time by an individual. For
this species, this parameter is important because changes in velocity can reflect dif
ferences in territorial tenure. Damselfly movements were separated according to the
direction travelled (upstream or downstream) and the age of the individual, looking
for net changes in total displacement (not daily movements). These estimates of
movements and velocity were made carefully only after checking the number of days
elapsed between recaptures to avoid mistakes when assigning ages.
Morisita's (1959) index of dispersion, Lloyd's (1967) mean crowding index and the
variance-to-mean ratio (Southwood 1979) were used to analyze population disper
sion. For each method, values less than one indicate a uniform distribution, values
greater than one indicate an aggregated distribution and a value of one indicates a
random distribution. All X2 analyses include Yate's correction factor.


RESULTS

A total of 208 individuals was marked (Table 1). Recaptures differed greatly be
tween sexes, showing, as in other studies, a greater percentage of males. An impor
tant factor in the study was that female numbers were low, probably because of a
natural seasonal decline. Results referring to females must be interpreted carefully.


Population Size, Survivorship and Recruitment

The results of the estimates by Jolly's method are summarized in Table 2. There
are two population peaks (see Fig. 2) on days 10 and 17 (about 1080 and 2700 indi
viduals, Table 2). After day 17, the population decreased sharply. Population esti
mates probably increase on sunny days after a few days of rain, as could have been
the case for days 7, 12 and 13 when strong rains fell on the river. However, this does
not explain the peak on day 10 because it did not rain on day 9 (however, it should
also be noted that one of the largest standard errors also occurred on day 10).


TABLE 1. RECAPTURE INDEXES OF HETAERINA CRUENTATA. N = TOTAL CAPTURED
INDIVIDUALS, RC = NUMBER OF INDIVIDUALS RECAPTURED, %RC = PRO
PORTION OF MARKED INDIVIDUALS RECAPTURED.

Sex N RC %RC
Male 182 118 64.8
Female 26 6 23.07
Totals 208 124 59.6


June, 1994







Cordoba Aguilar: Survival and Movement in a Damselfly 259


TABLE 2. POPULATION PARAMETERS OF HETAERINA CRUENTATA ESTIMATED PER DAY
BY JOLLY METHOD (1965). M = MARKED POPULATION ESTIMATES, N = POP
ULATION SIZE, SURV = SURVIVORSHIP, B = NUMBER OF ANIMALS ENTERING
INTO POPULATION, AND SE = STANDARD ERRORS.

Days M N+SE Surv+SE B
3
4 291 385+34 1.44+0.18 64
5 437 621+101 0.95+0.15 4
6 427 588+104 0.77+0.09 41
8 341 496+58 2.61+0.71 216
10 933 1083+295 0.35+0.09 73
11 337 462+61 2.44+0.79 344
14 849 786+242 0.86+0.32 219
15 732 898+192 1.54+0.64 98
16 1145 1288+479 1.91+1.27 237
17 2204 2708+1511 0.57+0.38 46
18 1279 1611+608 0.45+0.21 162
19 582 888+280 1.25+0.69 141
20 757 976+465 0.38+0.23 23
21 293 395+162
24


Survivorship fluctuated greatly. On several occasions, values higher than one
were obtained; such values make no biological sense. The daily survival rate reflects
the differences in the number of recaptures. High recapture rates were associated
with high daily survival rates. The estimated survival curve for males captured on
the first day, is shown in Fig. 3. This survival curve included individuals of all ages
except tenerals (JM n = 9, M n = 7, OM n = 43). The curve clearly shows a decline
throughout the study. No analysis of females was made due to their infrequent re
captures.
Average survival rate was 0.978 per day, which, when converted to life expectancy
by Cook et al.'s method is 44.9 days. This result is compared with the survivorship
and life expectancy of males of other species in Table 3.

Dispersion, Movements and Velocity

Morisita's index of dispersion for males was 3.63 which is statistically different
from one (p < 0.05). Lloyd's mean crowding index was 2.190.01 (S.E.) while the vari
ance-to-mean ratio (Southwood 1978) was 2.75. All three indices indicate aggregated
distributions. Aggregations of individuals in the central portion of the study site can
be seen in Fig. 1.
The same number of JM males moved up the river as down. In M males, more in
dividuals moved downstream, but the difference was not significant (%2 = 0.02, d.f.
1, p > 0.05). More OM males moved upstream than down, but this difference was also
not significant (2 = 0.93, d.f. = 1, p > 0.05). There was, however, a significant differ
ence when the number of individuals of each age dispersing was compared with
those remaining in the same quadrat among recaptures. More OM and JM males re
mained in the same quadrats (or very close) (x2 = 16.6, d.f. = 1, p < 0.001 for OM, X2
5.66, d.f. = 1, 0.05 > p > 0.01 for JM). Nevertheless, among M individuals none re
mained on the same quadrat for all recaptures (n = 25). Although there were more
animals (regardless of age) that moved upstream (64%) than downstream (36%), the






Florida Entomologist 77(2)


4 5 6 810111415161718192021

Date in September
Fig. 2. Estimated population size in Hetaerina cruentata as estimated by Jolly
(1965) method in the study. Vertical lines are standard errors.

TABLE 3. AVERAGE SURVIVORSHIP COMPARISONS AMONG MALES IN SEVERAL SPECIES
OF CALOPTERYGIDAE AND THEIR EXPECTED VALUE IN DAYS. 1 = CORDERO
(1989), 2 = CONRAD & HERMAN (1990), 3 = HIGASHI (1976 IN CORDERO,
1989), 4 = NOMAKUCHI ET AL. (1988), AND 5 = THIS STUDY. ESTIMATES IN
PARENTHESES IN CALOPTERYX HAEMORROIDALIS AND MNAIS PRUINOSA (4)
REFER TWO COMPARATIVE AVERAGES.
Species Avg Days
Calopteryx virgo (1) 0.86 6.6
C. haemorroidalis (1) 0.94 (0.91) 16.2 (10.6)
C. xanthostoma (1) 0.66 2.4
C. aequabilis (2) 0.767 3.8
Mnais pruinosa (3) 0.943
M. pruinosa (4) 0.944 (0.947) 17.6 (18.4)
Hetaerina cruentata (5) 0.978 44.9


June, 1994






Cordoba Aguilar: Survival and Movement in a Damselfly 261


4 5 6 8 1011 1415161718192021

Date in September
Fig. 3. Estimated percent of survivorship in males of Hetaerina cruentata cap
tured in the first day of study (n = 59).


difference was not significant (X2 = 1.05, d.f. = 1, p > 0.05). Movement patterns of ten
erals and females could not be estimated.
Scott's velocity indices were as follows: time in days between first and last recap
ture in males was 11.4, mean of total distance travelled in m was 44.3, and the mean
velocity was 3.9 m per day. For individual velocities, males only and different age
classes were analyzed separately. The procedure used was to take the quadrat of the
first recapture (after capture) and calculate the number of days between captures.
This short interval among captures meant age did not change much between cap
tures. There were no velocity differences among age classes (one-way ANOVA, p >
0.05). Distances travelled between males and females differed significantly (t test =
2.13, d.f. = 29, p < 0.025). Females had higher velocity patterns as in other species of
Calopteryx(see Cordero 1989, Conrad & Herman 1990, Waage 1972). The differences
among tenerals and the other age classes is probably great because a general was
never recaptured within 15 m of the river. Two males travelled 66.9 m between suc
cessive recaptures while other males remained in the same quadrats for several
days. This fact has been reported previously for other calopterygid species [He






Florida Entomologist 77(2)


taerina americana (Fabricius), Johnson 1962; H. vulnerata, Alcock 1982; H. macro
pus Selys, Eberhard 1986].


Sex Ratio and Mortality

Operational sex ratio always was notably skewed toward males (182 males, 26 fe
males), but these estimates do not reflect the primary sex ratio and result mainly
from behavioral differences between the sexes. Estimates of sex ratio were obtained
also by sexing larvae. In spite of a slight deviation toward females (43 females, 36
males), the ratio was not significantly different from 1:1 (2 = 0.455, d.f. = 1, p >
0.05).
During the study, no attacks by vertebrates like birds, frogs or fishes were noted
although they are usually regarded as common predators of other odonates. On one
occasion an ovipositing female was attacked by a giant aquatic bug (Family Belosto
matidae). Some newly emerged individuals were found in spider webs. Although the
sampling quadrats increased spider density by providing new, favorable places for
webs, no adults of H. cruentata were observed in these webs.


DISCUSSION

Population size (Fig. 2) may have changed during the study as a result of strong
rains, which affected afternoons and occasionally whole days. The rains may also
have been responsible for the highly fluctuating survivorship (Table 2). However,
other reasons exist for these changes (predation, migration, among others) that
could not be measured. As the study progressed, captures decreased and this affected
several additional parameters, including the Jolly's estimates (especially the S.E.'s).
Cordero (1989) found that recaptures (% RC) in three species of Calopteryx
(haemorroidalis, xanthostoma and virgo L.) did not exceed 53% for both sexes. The
highest percentage was for C. virgo (54%). In this respect, H. cruentata males
showed a relatively high percentage (64.8%, Table 1) of recaptures. The highest fre
quency of recaptures for a damselfly is that of Ischnura gemina (Kennedy) (Garrison
& Hafernik 1981) with 84% for both sexes and 90% for males alone. In addition, if it
is assumed that during the study the population was at low density when compared
with other months (pers. obs.), then the high recapture rates (higher than other spe
cies of Calopterygidae) could result because males are better able to successfully de
fend territories for several days when there is relatively little competition for sites.
Comparisons within the calopterygids and with other species are needed to test this
hypothesis.
Primary sex ratio was not different from one in H.cruentata. The same occurs in
other members of the calopterygids as Calopteryx virgo, C. haemorroidalis, C. xan
thostoma, C. virgo (Cordero 1989), C. maculata (Beauvois), C. dimidiata (Waage
1980). Waage (1980) has pointed out that the sex ratio should be 1:1 among all odo
nates.
Survivorship estimated by Jolly's method was quite variable (Table 2), but shows
a general decline over the month. Some of the variation probably results from include
ing several age classes in the analysis. The curve declines mainly due to the mortal
ity of OM animals. JM individuals presumably experience different mortality
pressures. It is interesting to note that the survival rate by Cook et al.'s method was
the highest (44.9 days) in the suborder, and perhaps for odonates in general. Corbet
(1958) has pointed out that adult life-span of neotropical damselflies is longer com-
pared with those of temperate latitudes, presumably due to less variable abiotic con
editions in the tropics. However, reduced energetic expenditures may have also
lengthened life in H. cruentata. These factors could include reduced activity in rainy


June, 1994







Cordoba Aguilar: Survival and Movement in a Damselfly 263


days because of cooler temperatures or reduced competition for territories due to low
density conditions.
H cruentata is a territorial species with behavioral biology similar to other calop
terygids (C6rdoba-Aguilar 1994). Several males perch, aggressively defending cer
tain areas (oviposition sites) against other males, where females arrive, searching
for copulation and oviposition. These sites have high male density in relation to oth
ers where oviposition sites do not exist. Under low density conditions, movement of
mature males are minimal, and presumably male velocity diminishes due to the
availability of many defensible territories, as has been demonstrated in Calopteryx
aequabilis Say at low density by Conrad & Herman (1990). Likewise, when density is
modified, other behavioral parameters are modified too. For example, fights among
territorial males in Mnaispruinosa Selys at the transitional period (when there were
mature and immature individuals in the population and at, presumably, low density)
influenced movements on the stream of individuals that could not win a territory
(Nomakuchi & Higashi 1985). Once these males established their territories, and
density was higher, they moved infrequently (Nomakuchi & Higashi 1985). This re
sult was similar to territorial males of H. cruentata. However, other conditions can
influence dispersal and movements. In general, animals experiencing poor feeding or
mating opportunities are usually more likely to disperse than those with good condi
tions (Lomnicki 1978, Lawrence 1987).
On the other hand, the few differences among age classes in movements and ve
locities are interesting. Eberhard (1986) observed that Hetaerina macropus Selys pe
riodically left the river but had a low tendency to disperse, in general. Cordero (1989)
found that in Calopteryx haemorroidalis, juvenile males moved greater distances
than mature males, and movements in C. xanthostoma were up river probably re
sulting from strong winds. Likewise, Higashi & Ueda (1982) found similar results in
a greater percentage of individuals of C. cornelia (Selys). Nevertheless, H cruentata
males did not display significant upstream or downstream movements. More studies
are needed to examine dispersal at high densities.


ACKNOWLEDGMENTS

Special thanks to F Capistran-Hdez., E. Estrada-C. and S. Bedoy-G. for helping
in the field work. Financial support was obtained as a part of a related project in
Ischnura denticollis from Sigma Xi, The Scientific Research Society. Thanks to I.
ChamorroF. for her constant support in the field data analysis, to R. Novelo-Gtz.
(IEX) and E. Gonzalez-S. (IBUNAM), for their criticisms and help with translation to
English. Finally, my deep appreciation to K. F Conrad (Canada) and S. D. Porter
(U.S.A.) for extensive suggestions that greatly improved the manuscript.


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idae) mating in contrasting topographic sites. J. Res. Lepidoptera 12: 181-196.
SCOTT, J. A. 1975. Flight patterns among eleven species of diurnal Lepidoptera. Ecol
ogy 56: 1367-1377.
SOUTHWOOD, T. R. E. 1979. Ecological methods. Chapman & Hall. London.
WAAGE, J. K. 1972. Longevity and mobility of adult Calopteryxmaculata (Beauvois,
1805) (Zygoptera: Calopterygidae). Odonatologica 1: 155-162.
WAAGE, J. K. 1980. Adult sex ratio and female reproductive potential in Calopteryx
(Zygoptera: Calopterygidae). Odonatologica 9: 217-230.
WILLIAMSON, E. B. 1923. Notes on the habitats of some tropical species of Hetaerina.
Publ. Michigan St. Univ. Mus. 130: 146.


June, 1994






Childers: Brevipalpus Feeding Injury & Control on Citrus 265


FEEDING INJURY TO 'ROBINSON' TANGERINE LEAVES BY
BREVIPALPUS MITES (ACARI: TENUIPALPIDAE) IN FLORIDA
AND EVALUATION OF CHEMICAL CONTROL ON CITRUS


CARL C. CHILDERS
Citrus Research and Education Center
University of Florida, IFAS
700 Experiment Station Road
Lake Alfred, FL 33850


ABSTRACT

Larvae, nymphs and adults of the false spider mites Brevipalpus phoenicis (Gei
jskes) and B. obovatus Donnadieu (Acari: Tenuipalpidae) were found feeding on the
ventral surface along the midrib of 'Robinson' tangerine leaves during December
1990. Resinous irregular areas were present in association with the chlorotic mid
vein areas of injured cells on the lower leaf surface. Similar injury was occasionally
evident on some lateral veins in association with the mites. Yellowed, blistered areas
were evident on the upper leaf surface opposite the injured areas on the lower leaf.
Leaf drop was evident only on trees that were heavily infested with false spider
mites. This type of leaf injury by Brevipalpus mites has not been previously reported
on Florida citrus. Chemical control evaluations showed that AC 303,630 in combine
tion with petroleum oil, pyridaben, fenbutatin-oxide, dicofol or high rates of sulfur
provided at least 35 days control. Ethion was less effective and carbaryl failed to con
trol these mites.
Key Words: Tenuipalpidae, injury, false-spider mites.

RESUME

En diciembre 1990, se encontraron larvas, ninfas y adults del acaro falso Brevi
palpus phoenicis ( ,1 I. i y B. ovatus Donnadieu (Acari: Tenuipalpidae) alimentan
dose en el envez de las hojas de mandarina "Robinson". Se observaron areas
resinosas irregulares conjuntamente con areas cloroticas en la nervadura central en
el envez. Un dano similar se encontr6 ocasionalmente en algunas nervaduras se
cundarias. En el haz se observe, amarillamiento y ampollamiento de las areas afecta
das. Se observe defoliaci6n unicamente en aquellos arboles con una gran infestaci6n
de acaros falsos. Este tipo de dano no ha sido reportado en citricos en Florida. Las
evaluaciones de control quimico demostraron que AC 303,630 en combinaci6n con
aceite, pyridaben, fenbutatin-oxide, dicofol o altas dosis de azufre brindaban control
por 35 dias. Ethion fue menos efectivo y carbaryl no control estos acaros.



Three species of false spider mites [Brevipalpus californicus (Banks), B. obovatus
Donnadieu, and B. phoenicis (Geijskes) (Acari: Tenuipalpidae)] have been collected
from citrus in Florida (Denmark 1984). All three species are cosmopolitan and occur
on citrus in Asia, Africa, Australia, Europe, the Middle East, South America, and the
United States (Jeppson et al. 1975). These mites feed on fruit, stems, branches, and
leaves of citrus. On leaves, they are most commonly found on the lower surface near
the midrib or veins.
False spider mites are reddish in color, slow moving, and not readily detected be
cause of their small size and sluggish behavior. They are about 260 pm in length
(Muma 1961). Brevipalpus mites are found on many perennial plants and have rela
tively long life cycles compared with other phytophagous mite pests, especially on

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. O. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
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Florida Entomologist 77(2)


citrus. Population levels of these mites tend to increase slowly due to their relatively
long life cycle (i.e., 35 days at temperatures between 70 and 85'F) (Manglitz & Cory
1953).
The greatest concern with Brevipalpus species on citrus in Florida and elsewhere
in the world has been their association with the viral disease, leprosis (Chiavegato et
al. 1982). Leprosis and infestations of B. californicus very nearly destroyed the citrus
industry in Florida before the late 1920's (Knorr et al. 1968). Leprosis was first ob
served in Florida in the 1860's and ultimately was found in 17 counties that essen
tially represented the total citrus growing area within Florida at that time. The
problem disappeared from Florida citrus in the late 1920's apparently following the
widespread usage of sulfur for mite control (Knorr et al. 1968).
Symptoms of leprosis have been reported to occur on fruit, leaves, shoots and
large limbs. Chestnut-brown spots from pinhead size to 6 mm in diameter occur on
oranges (Knorr 1973). In Florida, this malady has been referred to as nailhead rust
(Knorr & Price 1958). Similar lesions occur on both upper and lower leaf surfaces, es
pecially along the margins. Scaly lesions, called scaly bark, grow on the twigs (Knorr
& Price 1958).
Chiavegato et al. (1982) conducted transmission studies with the virus causing
leprosis and its vector B. phoenicis. The causal agent of leprosis is presumed to be a
mite-vectored bacilliform virus (Garnsey et al. 1988). Leprosis has been transmitted
by larvae of B. phoenicis after a 24 h acquisition period but nymphs and adults were
less efficient (Chiavegato & Salibe 1984).
According to Knorr (1959), only B. californicus has been associated with this dis
ease in Florida. B. obovatus has been associated with leprosis in Argentina and Ven
ezuela (Garnsey et al. 1988). B. phoenicis is the vector in Brazil (Chiavegato et al.
1982).
Knorr et al. (1968) found foliar and fruit lesions on 'Valencia' orange that were
similar in color, size and diameter to those caused by leprosis. However, correspond
ing lesions on shoots, twigs or branches were not evident. Large populations of B.
californicus and B. phoenicis were associated with a rind spotting of grapefruit in
Texas between June and October 1966. The injury was only on fruit and resembled
leprosis-like spotting (Dean & Maxwell 1967).
Brevipalpus gall or nodal galling resulted from B. phoenicis feeding on citrus
seedlings in Venezuela and Florida (Knorr & Denmark 1970). Plants subsequently
died since they were unable to leaf out. They further reported leaf drop on sour or
ange seedlings where B. phoenicis occurred in association with the fungus Elsinoe
fawcetti Bitancourt & Jenkins. Another foliar problem called phoenicis blotch has
been reported in association with B. phoenicis on Florida citrus. Diffuse chlorotic
spotting of foliage in sweet orange trees occurred which resembled early stages of
leprosis. However, no gumming of the affected areas occurred (Knorr et al. 1960).
Because little attention has been given to Brevipalpus mites in recent years, it is
appropriate to review chemical control of these potentially serious pests. These mites
have been observed in many citrus groves throughout Florida in conjunction with
other research activities (unpub. data). A serious leaf drop problem caused by high
populations of B. phoenicis and B. obovatuswas identified in 'Robinson' tangerine. In
jury to leaves and subsequent chemical control evaluations are reported in this paper.


MATERIALS AND METHODS

A'Robinson' tangerine grove located in Haines City, Polk County, Florida was vis
ited on 28 December 1990. The grower had complained about extensive leaf drop to
his 3-year-old trees. Several trees were examined. Only Brevipalpus mites were
found associated with leaf injury. They were removed for slide mounting in Hoyer's


June, 1994






Childers: Brevipalpus Feeding Injury & Control on Citrus 267


medium (Krantz 1978) and subsequent identification to species. No other arthropods
were found on the leaves.
Chemical control of Brevipalpus mites was assessed during 1991 and 1992. Both
experiments were established in a 'Hamlin' orange grove of 20+-year-old trees in
Hardee County that were 2.4 to 3.7 m high with 3 to 4.6 m canopy diameters and in
fested with moderate numbers of Brevipalpus mites. Tree spacing was 3.7 by 8.5 m
with 321 trees per hectare. Pesticide treatments were applied dilute in 5,574 liters of
water per ha with a handgun using a truck-mounted sprayer at 350 psi on 3 July
1991. The 1992 field experiment was established in the same grove site. Treatments
were applied dilute in 7,781 liters of water per ha with a handgun on 1 July 1992.
Experimental miticides included AC 303,630 [4-bromo-2 (4-chlorophenyl)-1
(ethoxymethyl)-5-(trifluoromethyl) pyrrole-3-carbonitrile] (American Cyanamid
Corp., Princeton, NJ) formulated as a 24% emulsifiable concentrate (EC) and a 22.5
g per liter (3 lb per gallon) soluble concentrate (SC), pyridaben formulated as 20 and
75% wettable powders (WP) (BASF Corp., Research Triangle Park, NC), and Mi
crothiol sulfur (ELF ATOCHEM Corp., Tifton, GA) was a micronized WP formula
tion containing 80% sulfur while the other sulfur compound was a 90% WP
formulation. The remaining pesticides included FC435-66 petroleum oil (Orchex
796), fenbutatin oxide (= Vendex), dicofol 4EC, ethion 4EC, and carbaryl 80S that
are registered for use on citrus.
Treatments were assigned at random to single tree plots in 1991 and in a random
ized complete block design in 1992 and replicated 5 times in both experiments. Each
sample tree was a vigorous, healthy tree representative of the block, and each plot
was separated from adjacent plots by at least one tree within and between rows.
Forty fruit were picked at random around the perimeter of each sample tree after
42 d post-treatment on 14 August 1991. Each fruit was agitated in a bucket contain
ing 80% ethyl alcohol, detergent, and bleach that was modified by increasing alcohol
concentration in a mixture developed by Gilstrap & Browning (1983). The solution
from each sample tree was poured into a separate labeledjar, returned to the labor
tory, and then poured into a gridded Petri dish and examined using a stereomicro
scope. The number of motile Brevipalpus mites per sample was counted.
In 1992, 20 fruit per sample tree were washed individually in a bucket containing
the alcohol detergent-bleach solution and vigorously shaken immediately after pick
ing. The solution from each sample tree was poured into a separate labeled jar and
returned to the laboratory where the contents were counted as before. Preliminary
sampling indicated that this method captured at least 95% of false spider mites on in
dividual fruit. A subsample of 10 to 20 mites from each of 2 or 3 water-sprayed trees
was slide-mounted and identified to species from sample dates during both years.
The mite count data in each treatment were subjected to Loglo (X + 1) transfer
nations for statistical analysis using PROC ANOVA (SAS Institute 1991). Untrans
formed counts are presented for comparison in the tables. If the difference between
treatments was significant (P< 0.05), Duncan's (1955) new multiple range test was
used to separate treatment means.

RESULTS AND DISCUSSION

Brevipalpus phoenicis and B. obovatus were identified from larvae, nymphs and
adults collected from the injured 'Robinson' tangerine leaves in Haines City (Fig. 1A
and B). Yellow blistered areas on the upper leaf surface occurred along the lengths of
most infested leaves. Resinous irregular injured areas were present in association
with the chlorotic midvein areas of injured cells on the lower leaf surfaces. No indi
cation of mesophyll collapse (Pratt 1958) was evident. Similar injury was occasion






Florida Entomologist 77(2)


Fig. 1. (A) Brevipalpus sp. nymph. (B) Brevipalpus sp. adult. (C) Feeding injury
caused by B. phoenicis and B. obovatus. (D) Lower leaf surface feeding injury prima
rily along the midvein with some lateral vein injured areas (IA) and yellow blistered
area (BA) on the upper leaf surface.

ally evident on some lateral veins too. Considerable leaf drop of mite infested leaves
was evident (Fig. 1C and D) while adjacent non-infested 'Robinson' trees did not have
injured leaves or leaf drop. All of the mites were found on the ventral surface of each
infested leaf, mostly along the midvein, with motile numbers often exceeding 50 per
leaf. Occasionally, chlorotic or resinous areas between lateral veins on the lower leaf
surface were found infested with these mites. Mite infestations were heavier along
the four or five rows on the north edge of the grove during December 1990. Leaf drop
was confined to these trees. This type of leaf injury by Brevipalpus mites has not been
previously reported on Florida citrus. None of the types of injury previously described
from other countries corresponded to foliar injury and leaf drop reported here.
Three adult B. phoenicis and 5 adult B. obovatus specimens were identified from
a series of 20 prepared slides from the 'Robinson' tangerine trees in 1990. In the 1991
miticide experiment on 'Hamlin' orange, B. phoenicis and B. obovatus accounted for
68 and 32%, respectively, of the 34 specimen identifications. Slide-mounted speci
mens identified from subsamples collected between 9 July and 27 August 1992 were
86% (N = 139) B. phoenicis and 14% (N = 23) B. obovatus. According to Denmark
(1984), B. obovatus has rarely been found on Florida citrus. B. phoenicis was the
principal false spider mite observed during this study on both 'Robinson' tangerine
and 'Hamlin' orange in Central Florida. B. californicus was not recorded during this
study.
In 1991, AC 303,630 at both rates, pyridaben 75 WP and dicofol all provided sig
nificantly better control compared with the water sprayed trees and Microthiol sul
fur after 42 days (Table 1).


June, 1994







Childers: Brevipalpus Feeding Injury & Control on Citrus 269


TABLE 1. NUMBERS OF BREVIPALPUS PHOENICIS (GEIJSKES) AND B. OBOVATUS DON
NADIEU ON 'HAMLIN' ORANGE FRUIT TREATED ON 3 JULY 1991.

Post-treatment Means of
Motile Mites per 40 Fruit1
Rate per 378 14 Aug
Treatment and Formulation Liters +42 d
AC 303,630 24% EC 100 ppm 3.6 c
AC 303,630 24% EC 200 ppm 2.6 c
Pyridaben 20 WP 181 g 8.2 bc
Pyridaben 75 WP 48 g 4.8 c
Dicofol 4 EC 355 ml 1.0 c
Microthiol sulfur 80% WP 1.8 kg 21.8 ab
Water spray 34.4 a


F 6.12, df 6,28,P 0.0003
1Means within a column followed by the same letter are not significantly different by ANOVA followed by
Duncan's NMRT.



In 1992, both rates of AC 303,630 + petroleum oil, fenbutatin-oxide, and both
rates of sulfur provided significantly better control of the mites through 35 days post
treatment compared with the other treatments (Table 2). Pyridaben and ethion pro
vided significantly better control of Brevipalpus spp. compared with the water
sprayed check trees; carbaryl was ineffective.
The new miticides (i.e., AC 303,630 and pyridaben) were compared against estab
lished standards (i.e., sulfur, fenbutatin-oxide, dicofol) for control of Brevipalpus
mites on Florida citrus.
B. phoenicis has been reported to be susceptible to sulfur, dicofol and chloroben
zilate while organophosphate and carbamate pesticides are ineffective (Jeppson et
al. 1975). Results from these studies confirm that carbaryl was ineffective in control
ling Brevipalpus mites. Ethion showed activity against these mites; however, it was
not as effective as AC 303,630, sulfur or fenbutatin-oxide.
Miticide evaluations for control of B. phoenicis on tea in Kenya showed that
flucythrinate, dicofol, omethoate, dimethoate, and permethrin were also effective.
However, significant yield increases were obtained only in the flucythrinate and per
methrin treatments (Sudoi 1990). In Brazil, dicofol at 37 g AI per 6 liters of water,
clofentezine at 9.45 g AI per 6 liters of water and RU-1000 (an experimental pyre
throid) at 1.76 or 2 g AI per 6 liters of water were effective at least 35 days following
treatment in controlling B. phoenicis on citrus (Mariconi et al. 1989). Cyhexatin at
20 g AI per 100 liters, binapacryl at 50 g AI per 100 liters and bifenthrin at 5.6 g AI
per 100 liters were most effective in controlling B. phoenicis on citrus in Brazil
(Arashiro et al. 1988).


ENDNOTE

Thanks to Gregory Evans for verification of mite species. Technical assistance
provided by Paul M. Keen, Jr., Michael G. Warmington, and Deanna K. Threlkeld
was greatly appreciated. Florida Agricultural Experiment Station Journal Series
No. R-03583.








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REFERENCES CITED

ARASHIRO, F. Y., A. J. RAIZER, C. A. SUGAHARA, R. MOTA, J. M. SILVA, AND F. A. M.
MARICONI. 1988. New field tests for chemical control of the citrus leprosis mite
Brevipalpus phoenicis (Geijskes, 1939) on orange trees. Anais da Escola Sup.
Agric. Luiz de Queiroz 45: 67-78.
CHIAVEGATO, L. G., M. M. MISCHAN, AND M. A. SILVA. 1982. Prejuizos e transmissi
bilidade de sintomas de leprose pelo acaro Brevipalpus phoenicis (Geijskes,
1939) Sayed, 1946 (Acari, Tenuipalpidae) em citros. Cientifica 10: 265-271.
CHIAVEGATO, L. G., AND A. A. SALIBE. 1984. Transmissibility of leprosis symptoms by
Brevipalpus phoenicis to young citrus plants under laboratory conditions, pp.
218-221 in S. M. Garnsey, L. W. Timmer, and J. A. Dodds [eds.] Compendium
of citrus diseases. Proc. Conf. Int. Organ. Citrus Virol. 9th. IOCV, Riverside,
California.
DEAN, H. A., AND N. P. MAXWELL. 1967. Spotting of grapefruit as associated with
false spider mites. Proc. Rio Grande Valley Hort. Soc. 21: 35-45.
DENMARK, H. A. 1984. Brevipalpus mites found on Florida citrus (Acarina: Tenuipal
pidae). Florida Dept. Agric. & Consumer Serv., Div. Plant Ind. Entomol. Circ.
69.
DUNCAN, D. B. 1955. Multiple range and multiple F test. Biometrics 11: 142.
GARNSEY, S. M., C. M. CHAGAS, AND L. G. CHIAVEGATO. 1988. Leprosis and zonate
chlorosis, pp. 43-44 inJ. O. Whiteside, S. M. Garnsey, and L. W. Timmer [eds.]
Compendium of citrus diseases. APS Press, The American Phytopathological
Society, St. Paul, Minn.
GILSTRAP, F. E., AND H. W. BROWNING. 1983. Sampling predaceous mites associated
with citrus. Texas Agric. Exp. Sta. PR-4139. 5 p.
JEPPSON, L. R., H. H. KEIFER, AND E. W. BAKER. 1975. Mites injurious to economic
plants. Univ. California Press, Berkeley. 614 p.
KNORR, L. C. 1959. Presenting Brevipalpus mites and some questions that they pose.
Citrus Mag. 21: 812, 20, 22.
KNORR, L. C. 1973. Citrus diseases and disorders, an alphabetized compendium with
particular reference to Florida. Univ. Presses of Florida, Gainesville. 163 p.
KNORR, L. C., AND H. A. DENMARK. 1970. Injury to citrus by the mite Brevipalpus
phoenicis. J. Econ. Entomol. 63: 1996-1998.
KNORR, L. C., H. A. DENMARK, AND H. C. BURNETT. 1968. Occurrence of Brevipalpus
mites, leprosis, and false leprosis on citrus in Florida. Florida Entomol. 51: 11
17.
KNORR, L. C., ANDW. C. PRICE. 1958. Leprosis, pp. 112-114 inR. M. Pratt [ed.], Flor
ida guide to citrus insects, diseases and nutritional disorders in color. Agric.
Exp. Sta., Gainesville, FL.
KNORR, L. C., B. N. WEBSTER, AND G. MALAGUTI. 1960. Injuries to citrus attributed
to Brevipalpus mites, including Brevipalpus gall, a newly reported disorder in
sour-orange seedlings. FAO Plant Prot. Bull. 8: 141-148.
KRANTZ, G. W. 1978. A manual of acarology 2nd ed. Oregon State Univ. Book Stores,
Inc., Corvallis.
MANGLITZ, G. R., AND E. N. CORY. 1953. Biology of Brevipalpus australis. J. Econ.
Entomol. 46: 116-119.
MARICONI, F. A. M., R. C. RANGEL, R. HAMAMURA, A. I. CLART, L. F. MESQUITA,
M. A. C. CARDOSO, AND E. B. REGITANO. 1989. Citrus leprosis mite Brevipal
pus phoenicis (Geijskes, 1939): Field test of chemical control. Anais da Escola
Sup. Agric. Luiz de Queiroz 46: 473-483.
MUMA, M. H. 1961. Mites associated with citrus in Florida. Florida Agric. Exp. Sta.
Bull. 640.
PRATT, R. M. 1958. Florida guide to citrus insects, diseases and nutritional disorders
in color. Agric. Exp. Sta., Gainesville, FL.
SAS INSTITUTE. 1991. SAS language and procedures: Usage 2, Version 6, First ed.
SAS Institute, Cary, NC.
SUDOI, V. 1990. Evaluation of different acaricides for control of red crevice mite
Brevipalpus phoenicis C. ,. (Acari: Tenuipalpidae) infesting tea. Trop.
Pest Management 36: 349-352.






272 Florida Entomologist 77(2) June, 1994


DEVELOPMENT OF NESTS AND COMPOSITION OF
COLONIES OF NASUTITERMES NIGRICEPS
(ISOPTERA: TERMITIDAE) IN THE
MANGROVES OF JAMAICA


P. A. CLARKE AND ERIC GARRAWAY
Department of Zoology, The University of the West Indies,
Mona, Kingston 7, Jamaica West Indies

ABSTRACT

Colonies of Nasutitermes nigriceps (Haldeman) inhabiting the island of Jamaica
were extracted from their arboreal carton nests by a two-stage method in which the
termites were dislodged from their galleries and separated from nest debris by flota
tion in water. Recovery of termites by this process was 97.7%.
No incipient nests were observed and all small nests collected consisted of both a
wooden region, which housed the reproductive, and an external carton nest. Except
for the soldier caste, the proportion of sterile castes was similar in both regions of the
nest. The size of small nests increased with little changes in the total colony size.
However, the number of termites in the external carton nest increased with size of
colony.
Approximately 50% of the large nests contained reproductive. These colonies
were consistently monogynous and monandrous. Caste composition of N nigriceps
colonies was comparable at each sample site and in nests of both reproductive status.
However, large nests had a smaller proportion of immature termites, but similar pro
portion of soldiers. The average percentage of workers in small nests was proper
tional to that of large nests with reproductive, but less than large nests without
reproductive.
Key Words: Nasutitermes, termites nest, colony composition.

RESUME

Las colonies de Nasutitermes nigriceps (Haldeman) que habitan la isla de Ja
maica fueron extraidas de sus nidos arboreos por un m6todo de dos pasos mediante el
cual las termitas se separaron de sus galerias y se separaron del ripio usando un
metodo de flotaci6n en agua. El porcentaje de termitas recuperadas fu6 del 97.7%.
No se observaron nidos incipientes y todos los nidos pequenos consisitieron de
una parte lenosa en la cual se encontraron los estados reproductores, y un nido ex
terno de carton. A excepci6n de la casta de soldados, la proporci6n de castas esteriles
fu6 similar en ambas parties del nido.
El incremento del tamano de los nidos pequenos no signific6 un gran cambio en el
tamano de la colonia.
El 50 % de los nidos grandes contenian estados reproductores. Estas colonies eran
consistentemente monoginas y monandras. La composici6n de ambos estados repro
ductivos de las colonies de N. nigriceps fu6 comparable en cada sitio muestreado y en
cada nido. Sinembargo, nidos grandes tuvieron una proporci6n menor de estadosju
veniles de termitas, pero una proporci6n similar de soldados. El porcentaje promedio
de obreras en los nidos pequenos fue proporcional al de los nidos grandes con estados
reproductores, pero los nidos pequenos tuvieron un porcentaje menor de obreras que
los nidos grandes sin estados reproductores. Las colonies de Nasutitermes nigriceps
(Haldeman) que habitan la isla de Jamaica fueron extraidas de sus nidos arboreos
por un m6todo de dos pasos mediante el cual las termitas se separaron de sus gal
erias y se separaron del ripio usando un metodo de flotaci6n en agua. El porcentaje
de termitas recuperadas fu6 del 97.7%.



This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. O. Painter Printing Co., PO. Box 877, DeLeon Springs, FL. 32130.
Irus document was created with rameMaker 4.0.2







Clarke & Garraway: Nasutitermes Nests and Composition 273


The Caribbean island of Jamaica is the third largest in the West Indies and has
16 documented species of termites belonging to the families Kalotermitidae, Rhino
termitidae and Termitidae (Snyder 1956). Advanced species of the family Termitidae
are represented by Termes hispaniolae (Banks), Nasutitermes nigriceps (Haldeman),
Nasutitermes costalis (Holmgren), Nasutitermes hubbardi Banks. N nigriceps is the
most common and prominent species of arboreal termite on the island with popular
tions distributed in both natural forests and human-developed habitats.
Advanced species of termites enhance their survival by evolving specialized
castes protected in tough and complex nests. Previous studies of the composition of
Nasutitermes colonies have been documented in N rippertii (Rambur) (Krecek 1970),
N. costalis (Krecek 1970, Clarke 1990), N corniger (Motschulsky) and N ephratae
(Holmgren) (Thorne 1985), N exitiosus (Hill) (Watson & Abbey 1987). Unfortunately,
the data are not comparable because of differences in extraction methods and accu
racy of results. The problem of ascertaining the composition and size of N. nigriceps
colonies was surmounted in this study by the use of a simple and replicative extrac
tion process, which yields almost full recovery of termites in nests. The density of
nests and growth pattern of colonies, including the proportion of castes at various
stages of development, were examined.


MATERIALS AND METHODS

The study focused on populations of N nigriceps inhabiting mangrove forests be
cause this environment offered virtually undisturbed, accessible nests that could pro
vide an accurate description of colony and nest development. The three study sites
selected were Port Royal, Hellshire and the North Coast. Four species of mangroves
occurred in these areas. In order of abundance these are Rhizophora mangle L. (red
mangrove), Avicennia germinans L. (black mangrove), Laguncularia racemosa
Gaertn (white mangrove) and Conocarpus erectus L. (buttonwood mangrove). Before
assessment of colonies commenced, the density of nests at each site was determined
by counting the number of live nests in 6 randomly chosen 30 m x 30 m quadrats. Vi
ability of nests was visibly assessed by creating holes in the upper, mid and lower re
gions of nests and observing the emergence or non-emergence of termites.
Between June 1987 and May 1988, five nests per month were randomly selected
from each site. Each nest was half an ellipsoid in shape (Fig. 1) and the longest pe
rimeter, height and diameter of base were measured before removal of nest from the
supporting branch. These measurements were used to calculate the volume of the
nest. Both the carton and wooden sections of small nests were removed for analysis,
while those nests consisting solely of a carton structure were dislodged from the sup
porting branch by repeatedly hitting the branch with a hatchet. Each nest was
placed in a plastic bag and transported to the laboratory where it was first subdi
vided and fumigated with carbon dioxide in reinforced plastic bags for 10-15 min.
During stage one of the extraction process each piece of subdivided nest was further
broken into small pieces and shaken by hand to dislodge the termites from the gal
leries. The termites and nest debris resulting from shaking all the pieces of a whole
nest were collected in a tray and the empty pieces of nest from which the termites
had been removed were discarded.
Termites were separated from the nest debris during stage two of the extraction
process by flotation in water. The total mixture of termites and nest debris derived
from a single nest was submerged in water and allowed to stand for approximately
30 min. The nest material rapidly becomes saturated and sinks; then the floating ter
mites can be easily removed. For a clearer separation, small volumes of the total sus
pension were successively removed, stirred in water and allowed to stand for 10 min.
The water with the floating termites was decanted into a double sieve with upper
and lower mesh sizes of 0.05 mm and 0.025 mm, respectively. The remaining debris






Florida Entomologist 77(2)


T
Height


Perimeter Perimeter



of Base






Fig. 1. Structure of nest.


in the bucket was rewashed with water to ensure complete removal of termites. The
water was drained from the termites and the total amount of termites measured.
Three sub-samples of 5 ml each were removed and the number of each caste counted.
The total colony size and caste composition were calculated.
The efficiency of the two-stage extraction method was determined by processing
10 nests and assessing the amount of termites remaining in a) the pieces of nests to
be discarded after shaking the termites from the galleries and b) the waste residue in
the bucket after flotation. Unlike the powdery residue in the bucket after stage two,
the pieces of nests to be discarded after shaking were crumbled before flotation.
Complete retrieval of termites was determined by visual observation.
The mean percentages and standard deviation of sterile castes were calculated
from Arcsine transformed data (Sokal & Rohl 1981, Zar 1984). Only re-transformed
data are quoted in this paper; consequently, for some results the total percentage of
castes per nest are not equal to 100. Analysis of variance and Student's "t" test were
used for comparisons of means.

RESULTS

The density of N nigriceps nests varied in each sample site (Table 1). Port Royal
mangroves supported the highest number of live termite nests and, contrary to the
other sites, some nests were situated in proximity to each other. Consequently, dur
ing the monthly sampling, the number of nests collected from Port Royal was signif
icantly greater than Hellshire and the North Coast. Incipient nests were not
observed at the three sites and only a few small nests (N = 12) were found in the
mangroves of Port Royal. These small nests occurred in proximity to each other
while larger nests were widely separated (Fig. 2; Spearman Rank test r 0.8, P >
0.05). Each small nest consisted of an interconnecting wooden and an external carton
nest. The wooden nest was ramified with galleries and some areas were lined with


June, 1994






Clarke & Garraway: Nasutitermes Nests and Composition 275


TABLE 1. DENSITY OF NESTS IN THE THREE STUDY SITES.

No. of Live Nests1
Quadrat Port Royal Hellshire North Coast
1 0 (1) 0 (1) 1
2 2 (1) 1 0 (1)
3 3 0 (1) 1
4 2 0 (1) 1
5 5 1 1
6 3 (1) 1 1
x 2 0.5 1
1() No. of dead nests.



stercoral carton. The perimeter of the friable, external carton nest ranged from 10-35
cm. The number of termites in the external carton nest increased with colony size
(Fig. 3). Large nests with perimeters 34-130 cm (N = 101) consisted solely of an ex
ternal carton nest. The colony size of these large nests increased proportionally with
nest size (r = 0.5, P > 0.001), while in smaller nests there was an increase in the size
of nests with no corresponding increase in the number of termites (Fig. 4).
N. nigriceps nests were enlarged during the island's bimodal rainy season that
peaks in May and October. The direction of growth of small nests was multilateral,
but mainly negatively geotropic in large nests. The latter pattern of nest expansion
was consistent in large nests that had fallen from branches. The lower and older re
gion of large nests with perimeter greater than 87 cm were devoid of termites. The


NO. OF NESTS PER 30 M


200


Fig. 2. The relationship between the density (No. per 30m2) and perimeter of nests.


50 100 150
AVERAGE PERIMETER OF COLONIES (CM)


I I I I






Florida Entomologist 77(2)


3.5


RATIO OF WOOD TO CARTON TERMITES


2.5 k


1.5


0.5 F


0 e l

0 10 20 30 40
COLONY SIZE (xO000)
Fig. 3. The effect of colony growth on the distribution of termites in the wooden
and carton regions of nests.

walls were paler in color and separated easily between the fingers. These vacant gal
leries were invaded by inquilines.
The shaking-flotation extraction method produced a clean sample of sterile ter
mites devoid of nest debris. The mean number of termites per 5 ml ranged from 941
1195 (Table 2). The average recovery of termites by shaking and flotation was 98.3%
and 97.6%, respectively (Table 2). Total recovery of termites utilizing the two-stage
method was 97.7%. Colonies of N nigriceps consisted of the typical castes found in
termite societies. All small nests contained a pair of reproductive in the wooden nest
region. Approximately half of the large nests had a pair of reproductive protected by
a fortified royal chamber embedded within the core of the nest. The remaining nests
of similar sizes did not have reproductive and no royal chambers were found. Imma


June, 1994






Clarke & Garraway: Nasutitermes Nests and Composition 277


COLONY SIZE (x1000)
700r


600

500

400

300


200

100

0


ha aa at


0 [
[


0,".
0 g 0o


_ru


2 2.5 3 3.5 4 4.5 5 5.5 6
LOG VOLUME OF NESTS (cm )


6.5 7


" LARGE COLONIES


* SMALL COLONIES


Fig. 4. The relationship between the size of colonies and volume of nests.


ture termites and workers of small nests were equally distributed in the wooden and
carton regions (Table 3; P > 0.05), while soldiers occurred in large proportions in the
carton nest (P < 0.01). Although the proportion of sterile castes was highly varied in


TABLE 2. RECOVERY OF N NIGRICEPS FROM NESTS USING A TWO-STAGE EXTRACTION
METHOD.

Percentage of Termites Recovered
Mean No. of
Termites per
Nest No. Shaking Washing Total 5ml
1 97.2 93.7 95.5 1 195
2 99.2 98.6 98.9 964
3 99.0 91.3 95.2 1 066
4 98.5 95.8 97.2 1 046
5 98.6 98.6 98.6 941
6 92.2 98.5 95.4 987
7 92.6 97.4 95.0 1 083
8 99.1 98.9 99.0 1 034
9 98.8 99.3 99.1 1 001
10 99.9 99.2 99.6 1 146
Mean' 98.3 97.6 97.7
SD (min, max) 2.9, 1.5 2.9, 1.7 2.2, 1.5
1X and SD were calculated from Arcsine transformed data.






Florida Entomologist 77(2)


TABLE 3. THE MEAN PERCENTAGE (CALCULATED FROM ARCSINE TRANSFORMED DATA)
OF CASTES IN TWELVE SMALL NESTS OF N. NIGRICEPS.

Section of Nest'
Castes Wooden Region Carton Region
Larvae 20.9 (8.1; 37.9) 21.0 (4.7; 44.7)
Presoldiers 1.3 (0.4; 2.7) 1.2 (0.3; 2.6)
Soldiers 12.4 (7.6; 18.1) 17.1 (5.9; 32.4)
Workers 63.3 (45.1; 79.9) 55.2 (45.1; 79.7)
1Minimum and maximum SD in ().

large nests, the composition of castes was not influenced by geographical location
and presence of reproductive (Table 4). Small nests from Port Royal had a higher
percentage of larvae and presoldiers (immature individuals) than large nests (P <
0.01). The proportion of workers in small nests was similar to that of large nests with
reproductive (P < 0.01) but less than that of large nests without reproductive (P >
0.05). Soldiers were equally represented in colonies at different stages of nest devel
opment and reproductive status.

DISCUSSION

A N. nigriceps colony is initiated in a tree cavity by alates, and wooden galleries
are created to house the expanding colony. At a later stage of nest development an ex
ternal carton nest is built with walls composed primarily of stercoral material (par
tially digested wood). Initially, the nest material is malleable, but hardens with age.
Very little information is known about the dynamics of incipient colonies in the field
because of the clandestine nature of the termites and the absence of detectable exter
nal diagnostic features of nests. However, N. nigriceps colonies inhabiting small
nests with both wooden and external carton regions, increased carton nest space

TABLE 4. THE MEAN PERCENTAGES (CALCULATED FROM ARCSINE TRANSFORMED
DATA) OF CASTES IN LARGE NESTS OF N. NIGRICEPS.

Sites'
Castes Port Royal Hellshire N.W. Coast
Reproductives Present
Larvae 18.8 (11.1,25.9) 20.6 (16.6,25.5) 19.5 (19.4,19.6)
Presoldiers 1.8 (0.6,3.7) 1.6 (1.6,25.5) 1.1 (0.9,1.6)
Soldiers 14.5 (10.1,43.7) 14.5 (11.3,18.0) 13.7 (10.5,16.9)
Workers 80.7 (53.7,73.9) 78.8 (56.7,68.6) 82.4 (59.3,71.1)
N 30 8 8

Reproductives Absent
Larvae 16.8 (9.5,27.6) 23.7 (13.1,36.6) 33.4 (9.3,36.2)
Presoldiers 1.7 (0.4,3.3) 1.4 (0.3,3.0) 1.3 (0.0,2.0)
Soldiers 13.1 (9.1,14.3) 13.6 (10.2,17.0) 13.1 (10.7,17.3)
Workers 84.7 (55.9,78.0) 75.5 (49.1: 71.4) 76.4 (49.5:72.3)
30 12 13
'Minimum and maximum SD in ().


June, 1994







Clarke & Garraway: Nasutitermes Nests and Composition 279


with limited increase in total colony size. Such activity not only allows rapid devel
opment of a nest that offers better protection from biotic and abiotic factors, but also
creates an environment with a more stable and optimum micro-climate. The original
wooden nest is abandoned and the colony continues development in the carton nest.
Colony composition of N nigriceps varies with the stage of nest development. How
ever, the proportion of each caste seems to stabilize in large colonies at different lo
cations and is not influenced by proportional increase in colony and nest size. Thus,
the data presented in this paper may be applied to populations throughout Jamaica.
Mature colonies accommodate the increasing numbers of termites by seasonal ex
pension of nests. During the rainy season, N. nigriceps workers build in a negative
geotropic direction. Migration of termites within nests also follow a similar pattern
so that termites are continuously associated with fairly new stercoral walls. This in
ter-relationship may be linked to the homeostatic properties of stercoral material. A
review of Noirot (1970) showed the positive influence of stercoral walls on tempera
ture and humidity within nests. The homeostatic nature of stercoral walls of N nig
riceps nests may decline with age as seen in its physical parameters such as texture
and color. Further research is required for confirmation.
N nigriceps colonies with reproductive were consistently monogynous and mo
nandrous, but approximately half the nests were devoid of reproductive. The latter
may be either calies (subsidiary nests) or large nests which lost their reproductive.
Similarity in size of both types of nests, comparable caste composition, absence of a
royal chamber in queenless nests and distance between nests, suggest that these
large nests without reproductive are calies. Calies have never been recorded in N
nigriceps, but were documented in some members of the genus; N corniger (Thorne
1982), N costalis and N polygynous (Roisin and Pasteels 1986). While it is still not
clear what induces the development of calies, it has been suggested that they are
constructed in response to adverse conditions created by increase colony size (Holt &
Easey 1985; Adams & Levings 1987).
A hardened nest inhabited by a large colony hinders accurate determination of
the size and composition of the colony. The use of shaking and flotation as methods of
collecting insects is not a novelty (Southwood 1978), however, the two-stage method
described here has never been utilized to extract termites of the genus Nasutitermes.
This method is comparable with that used by Darlington (1984) and Thorne (1985).
Thorne (1985) removed N corniger and N ephratae (after inactivation by freezing)
by a similar shaking method, but the termites were not separated from the nest de
bris before subsampling thus, resulting in a variation of 400-900 termites per 5 ml
subsample. This highlighted the need for a second stage in the extraction method
that would provide a cleaner separation and ultimately increase precision. Darling
ton's (1984) study of Macrotermes spp. found flotation useful in separating termites
from the rubble generated from the dissection of their huge nests, hence developed a
special flotation tank. The two stage method used in this study allows rapid collec
tion of accurate data with the use of simple equipment such as buckets, trays and a
portable 10 lb cylinder of carbon dioxide.


ACKNOWLEDGMENTS

The research was funded by The University of the West Indies. We thank Dionne
Miller and Johanna P.E.C. Darlington for useful discussions.


REFERENCES CITED

ADAMS, E. S., AND S. C. LEVINGS. 1987. Teritory size and population limits in man
groves termites. J. Anim. Ecol. 56: 1069-1081.







Florida Entomologist 77(2)


CLARKE, P. 1990. Caste ratios in parent nests and calies of Nasutitermes costalis
(Holmgren). U.W.I. Biospectrum 2: 15-16.
DARLINGTON, J. P. E. C. 1984. A method for sampling the population of large termite
nests. Ann. Appl. Biol. 104: 427-436.
HOLT, J. A., AND F. J. EASEY. 1985. Polycalic colonies of some mound-building ter
mites (Isoptera: Termitidae) in Northeastern Australia. Insectes Sociaux,
Paris 32: 6169.
KRECEK, J. 1970. Nest structure, humidity and colony composition of two species of
Nasutitermes in Cuba (Isoptera: Termitidae). Act. Entomol. Bohemoslauoca,
67: 310-317.
NOIROT, C. 1970. The nests of termites, in K. Krishna and F. M. Weesner [eds.], Biol
ogy of Termites. Vol. II., Academic Press, New York, London. 693 pp. .
ROISIN, Y., AND J. M. PASTEELS. 1986. Reproductive mechanisms in termites: poly
calism and polygyny in Nasutitermes polygynous and Nasutitermes costalis.
Insectes Sociaux, Paris 33: 149-167.
SNYDER, T. E. 1956. Termites of the West Indies, the Bahamas and Bermuda. J.
Agric. of the University of Puerto Rico 60: 189-201.
SOKAL, R. R., AND F. J. ROHLF. 1981. Biometry W. H. Freeman and Company, New
York. 859 pp.
SOUTHWOOD, T. R. E. 1978. Ecological methods. Chapman and Hall. New York, Lon
don. 379 pp.
THORNE, B. L. 1985. Numerical and biomass caste proportions of colonies of termites
Nasutitermes corniger and Nasutitermes ephratae (Isoptera: Termitidae). In
sectes Sociaux, Paris 32: 411 426.
WATSON, J. A. L., AND H. M. ABBEY. 1987. Maternal determination of reproductive
vs sterile castes in Nasutitermes exitiosus (Hill) (Isoptera: Termitidae). In
sectes Sociaux, Paris, 34: 291-297.
ZAR, J. H. 1984. Biostatistical Analysis. Prentice Hall, New Jersey. pp. 718.


June, 1994






Scientific Notes


APPLICATION METHODS FOR ENTOMOPATHOGENIC
NEMATODES (RHABDITIDA: HETERORHABDITIDAE):
AQUEOUS SUSPENSIONS VERSUS INFECTED CADAVERS


RICHARD K. JANSSON AND SCOTT H. LECRONE
Tropical Research and Education Center
Institute of Food and Agricultural Sciences
University of Florida
Homestead, FL 33031

Entomopathogenic nematodes have potential as biological control agents of many
soil insect pests. These nematodes have a broad host range, and they are highly vir
ulent with high reproductive rates. They have the ability to seek out and quickly kill
hosts (even cryptic hosts) within 24-48 h, and they are safe to vertebrate and other
nontarget organisms (Gaugler 1981, Kaya 1985). In addition, these nematodes are
easy to apply using a variety of methods ranging from aqueous suspensions applied
by hand to those made with standard sprayers (up to 70.4 kg/cm2) and irrigation sys
teams (Kaya 1985, Georgis 1990).
Entomopathogenic nematodes have also been shown to have potential for control
ling field populations of the sweetpotato weevil, Cylas formicarius (Fabricius) (Jans
son et al. 1990, 1991, 1993). Heterorhabditid nematodes were superior to
steinernematids at reducing weevil populations and their concomitant damage to
storage roots (Jansson et al. 1990, 1993). Welch & Briand (1960) found that aqueous
applications of Steinernema carpocapsae (Weiser) DD136 strain, and those made us
ing infected greater wax moth, Galleria mellonella (L.), cadavers, were equally effec
tive at controlling cabbage root maggot, Hylemya brassicae (Bouch6). More recently,
Jansson et al. (1993) showed that applications of G. mellonella cadavers infected
with heterorhabditid nematodes were efficacious for controlling field populations of
C. formicarius and their concomitant damage; however, nematode applications via
infected cadavers were not compared with those made via aqueous suspensions. The
present study compared efficacy and persistence of a heterorhabditid nematode
against C. formicarius when applied via aqueous suspensions with those made using
infected G. mellonella cadavers.
The experiment was conducted in a Krome, very gravelly loam soil at the Tropical
Research and Education Center in Homestead. Sweet potato, Ipomoea batatas (L.)
Lam. cv. Jewel, transplants were hand planted 20 cm apart on raised beds with cen
ters spaced 1.9 m apart on 5 June 1991. All production practices were similar to
those described previously (Jansson et al. 1990, 1991, 1993). No herbicides or fungi
cides were applied to the experimental plot. Plants were drip irrigated 4 h per day
using a drip turbo T tape-irrigation system (model 40) (5.0 liter per m per h) from
shortly before planting until the experiment terminated.
A research plot (0.2 ha) was subdivided and arranged into a randomized complete
block design with four replications. Treatment plots were three beds by 15.2 m long.
A 3-m buffer of nontreated plants separated replicates. Treatments evaluated were:
a single aqueous application of Heterorhabditis bacteriophora Poinar HP88 strain
(4.9 billion infective juveniles per ha) made on 23 July 1991, a single application of 5
and 10-day-old G. mellonella cadavers (83,700 per ha) infected with H. bacteriophora
HP88 strain made on 26 July 1991, and nontreated plants. Jansson et al. (1991)
showed that a single application of H. bacteriophora HP88 strain was efficacious for
controlling populations of C. formicarius. Potential rates of infective juveniles ap
plied in the cadaver treatments were 6.4 to 18.3 billion infective juveniles per ha
based on mean numbers of infective juveniles produced per cadaver of between


This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
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Florida Entomologist 77(2)


76,260 and 219,181 (Jansson et al. 1993). Inoculation procedures were similar to
those described previously (Jansson et al. 1993).
Two 3-m sections were dug from the middle bed of each treatment plot on 19-20
December 1991. Storage roots were divided into three size categories (small, me
dium, and jumbo) and each individual root was then visually inspected for weevil
damage and rated on a scale from 1 to 6 (Jansson et al. 1990): 1, no weevil damage,
no feeding or oviposition scars, no adult exit holes; 6, severe weevil damage, > 6 adult
exit holes per root. The percentage of root biomass in each damage category and the
mean damage index were determined. The percentage of marketable roots was de
termined by calculating the percentage of medium-sized roots with a rating < 2 (Jan
sson et al. 1990).
Soil was assayed for native nematode populations once [19 July 1991, 12 soil sam
ples (720-1045 g each) per plot] before applications were made. Levels of recovery of
HP88 nematodes were determined on three dates after application (19 September, 5
December 1991 and 23 July 1992; 3 soil samples per treatment plot) using methods
described previously (Jansson et al. 1991, 1993). Soil was transferred to separate
plastic cups (1 liter) and ten late-instar G. mellonella were placed in the bottom of
each cup, covered with soil (Bedding & Akhurst 1975) and stored for 10-14 days in
the dark at 24+3'C after which cadavers were examined for nematode infection (Jan
sson et al. 1991, 1993).
Percentages of root weight in various damage categories were transformed to the
arcsine of the square root and analyzed by least squares analysis of variance (Zar
1984). Total numbers of infected G. mellonella larvae were compared among treat
ments by X2 analysis (Steel & Torrie 1980).
Percentages of roots that had no weevil damage (rating = 1), slight weevil damage
(rating = 2), or little or no damage (rating = 1 or 2) did not differ (F > 0.9, df = 3,9, P
> 0.05) among treatments (Table 1). Percentages of root weight in these three dam
age categories tended to be higher on nematode-treated plants than on nontreated
plants, although not significantly. These data suggest that aqueous applications of
nematodes were comparable in efficacy to those made using infected cadavers of G.
mellonella that were either 5 or 10 days old.
Few soil samples (0.7%, n = 388) and fewer G. mellonella larvae (0.1%, n = 3,880)
were positive for entomopathogenic nematodes before applications were made. After


TABLE 1. PERCENTAGES OF STORAGE ROOT WEIGHT WITH NO WEEVIL DAMAGE, SLIGHT
WEEVIL DAMAGE, AND NONE OR SLIGHT DAMAGE, ON SWEET POTATOES
TREATED WITH AQUEOUS OR CADAVER APPLICATIONS OF H. BACTERIA
PHORA HP88 STRAIN AND ON NONTREATED PLANTS.

% Root Weight
Treatment No Damage, Slight Damage, Little/No Damage,
Rate/ha2 Rating = 1 Rating = 2 Rating = 1 or 2
Aqueous,
4.9 B/ha 50.6+3.6 28.3+1.8 79.0+3.1
Cadaver, 5-day-old,
83,700/ha 47.9+6.9 31.1+3.6 79.0+3.7
Cadaver, 10-day-old,
83,700/ha 51.5+3.7 28.8+1.6 80.4+3.6
Nontreated 34.6+4.8 32.1+5.4 66.7+4.2
1Means within a column did not differ (P> 0.05) by least squares analysis of variance (Zar 1984).
2Aqueous applications are in terms of infective juveniles per ha; cadaver treatments are numbers of cadavers
per ha.


June, 1994






Scientific Notes


No. of Infected Galleria Larvae
80
Day after app.
65-58
60 M 132-135
S362-365


40



20



0 __
Aqueous Cadaver, 5 day Cadaver, 10 day Nontreated

Fig. 1. Total numbers of G. mellonella larvae infected with H. bacteriophora HP88
strain in sweet potato plots treated with aqueous suspensions of HP88 or cadavers of
G. mellonella infected with HP88 and in nontreated plots (n= 120 larvae per treat
ment).


applications, high levels of recovery of nematodes were found on the first two sample
dates (55-58 and 132-135 days after application) (Fig. 1). Little recovery was found
on the last sample date (362-365 days after application) approximately 7 months af
ter the experiment terminated. Recovery of nematodes did not differ (X2 < 8.8, df = 2,
P > 0.05) among the three nematode treatments, but was considerably higher in
nematode-treated plots than in nontreated plots (Fig. 1). Levels of recovery concur
with our previous experiments in which either aqueous suspensions or cadaver ap
plications were used (Jansson et al. 1991, 1993).
The data show that aqueous suspensions of HP88 nematodes were as effective as
applications of G. mellonella cadavers infected with HP88 for controlling damage by
sweetpotato weevil to storage roots. Also, we found that persistence of nematodes
was similar for the two of methods of application. Application of infected cadavers for
introducing nematodes was shown to have merit in a previous report (Jansson et al.
1993). Applications of nematodes via infected insect hosts may have potential for in
tegrating into developing countries because its simple and requires no special equip
ment and no water at the time of application. However, it does require a constant and
large supply of susceptible hosts and considerable space and labor. We encourage re
searchers to explore the possibility of using this approach in a variety of insect host/
crop systems.
We thank E. Murray and R. Lance for assistance with data collection and the
anonymous reviewers for their suggestions. This research was supported by
U.S.D.A., C.S.R.S., Tropical/Subtropical Agriculture Program, Grant Nos.
88-34135-3564 and 91 34135-6134 (to R.K.J.) managed by the Caribbean Basin Ad
ministrative Group (CBAG). The senior author is currently Senior Research Fellow,
Merck Research Laboratories, P. O. Box 450, Hillsborough Rd., Three Bridges, NJ
08887-0450. This is Florida Agricultural Experiment Station Journal Series No.
R-03090.







Florida Entomologist 77(2)


SUMMARY

Aqueous suspensions of HP88 nematodes were as effective as applications of Gal
leria mellonella cadavers infected with HP88 for controlling damage by sweetpotato
weevil to storage roots. Persistence of nematodes was similar for the two types of ap
plication.


REFERENCES CITED

GAUGLER, R. 1981. Biological control potential of neoaplectanid nematodes. J. Nem
atol. 13: 241-249.
GEORGIS, R. 1990. Formulation and application technology, p. 173-191 in R. Gaugler
and H. K. Kaya [eds.], Entomopathogenic nematodes in biological control.
CRC Press, Boca Raton, Florida, 356 p.
JANSSON, R. K., S. H. LECRONE, AND R. GAUGLER. 1991. Comparison of single and
multiple releases of Heterorhabditis bacteriophora Poinar (Nematoda: Heter
orhabditidae) for control of Cylas formicarius (Fabricius) (Coleoptera: Apion
idae). Biol. Control 1: 320-328.
JANSSON, R. K., S. H. LECRONE, AND R. GAUGLER 1993. Field efficacy and persis
tence of entomopathogenic nematodes (Rhabditida: Steinernematidae, Heter
orhabditidae) for control of sweetpotato weevil (Coleoptera: Apionidae) in
southern Florida. J. Econ. Entomol. 86: 1055-1063.
JANSSON, R. K., S. H. LECRONE, R. R. GAUGLER, AND G. C. SMART, JR. 1990. Potential
of entomopathogenic nematodes as biological control agents of the sweetpo
tato weevil (Coleoptera: Curculionidae). J. Econ. Entomol. 83: 1818-1826.
KAYA, H. K. 1985. Entomogenous nematodes for insect control in IPM systems, p.
283-302 in M. A. Hoy and D. C. Herzog [eds.], Biological control in agricultural
IPM systems. Academic Press, New York.
STEEL, R. G., AND J. H. TORRIE. 1980. Principles and procedures of statistics.
McGraw-Hill, New York, 633 p.
WELCH, H. E., AND L. J. BRIAND. 1960. Field experiment on the use of a nematode for
control of vegetable crop insects. Proc. Entomol. Soc. Ontario 91: 197-202.
ZAR, J. H. 1984. Biostatistical analysis. Prentice-Hall, Englewood Cliffs, New Jersey,
718 p.


June, 1994






Florida Entomologist 77(2)


EFFECT OF TILL AND NO-TILL SOYBEAN CULTIVATION ON
DYNAMICS OF ENTOMOPATHOGENIC FUNGI IN THE SOIL

D. R. SOSA-GOMEZ AND F. MOSCARDI
EMBRAPA Centro Nacional de Pesquisa de Soja, Cx P 1061.
Londrina, PR -86001-970. Brazil.

Several species of phytophagous insects are attacked by entomopathogenic fungi
of the Moniliacea family. In soybean agroecosystems, the most prevalent fungi are
Nomuraea rileyi (Farlow) Samson which infect caterpillars, and Beauveria bassiana
(Balsamo) Vuill. which attacks chrysomelids such as Diabrotica speciosa (Germar),
Cerotoma arcuata (Olivier), Colaspis spp. and curculionids, such as Aracanthus spp.
Other fungal species of lesser prevalence associated with soybean insects include
Metarhizium anisopliae (Metsch.) Sorok., which is found on j .'.' ,', .; .. cuyabana
(Moser) and other Scarabaeidae; Paecilomyces fumosoroseus (Wize) Brown & Smith
which cause epizootics in populations of Lagria villosa Fabr. (Coleoptera: Lagriidae);
and another species of Paecilomyces, probably tenuipes, which occurs at low levels in
the wet season on Anticarsia gemmatalis Hubner, Chrysodeixis includes (Walker)

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Shelly: Methyl eugenol consumption byBactrocera dorsalis 285


and Rachiplusia nu (Guenee) (D. Sosa-Gdmez unpublished). The prevalence of these
entomopathogenic fungi are affected by various abiotic and biotic factors including
cultural practices (Gaugler et al. 1989; Sosa-Gdmez & Moscardi 1992). The objective
of this paper was to study the effect of till and no-till cultivation practices on density
dynamics of entomopathogenic fungi in the soil.
The experiment was carried out in two contiguous areas of 22 x 312 m each, in
Londrina, state of Parana, Brazil, one under no-till cultivation and another under
conventional tillage. In the area under no-till, the soil was not cultivated during the
entire year. Double-croppings of soybean and wheat had been planted on these areas
since 1985. The soil type was classified as oxisols (soil taxonomy of Brazil = latossolo
roxo distr6fico epieutr6fico). Along the length of the two areas, nine paired plots (50
m2) were delimited in the 1989/90 season and eight paired plots (50 m2) in the 1990/
91 season. In each paired plot, eight soil core subsamples, 2 cm diam and about 2 cm
deep, were taken every two weeks from the soil surface from randomly selected sites
(1 m2). The majority of fungus inocula usually concentrate in this soil layer (Ignoffo
et al. 1977; Storey et al. 1989). The subsamples from each plot were combined and
mixed thoroughly in the laboratory. One-gram aliquots were taken per sample and
processed for colony forming units (CFUs) growing on selective medium (Chase et al.
1986). The number of CFUs per gram of dry soil was analyzed by the t-test procedure
of the Statistical Analysis System (SAS Institute 1985), so as to compare mean re
sponses between CFUs from tilled and untilled paired plots.
Significant differences (P < 0.05) in the number of CFUs recovered from the two
areas occurred at practically all sampling dates (Fig. 1). The predominant species
among the observed entomopathogenic fungi was B. bassiana reaching about 1.9 x
105 CFUs per g of soil on February 2, 1990 (Fig. la) and 3.3 x 104 CFUs per g of soil
on January 17, 1991 (Fig. Ib). The prevalence of B. bassiana explains the frequent
incidence of this fungus on populations of chrysomelids and pentatomids as reported
by Moscardi et al. (1985) and Daoust & Pereira (1986). M. anisopliae reached the
maximum level on January 19, 1990 with 1.2 x 104 CFUs per g of soil (Fig. Ic), and
1.1 x 104 CFUs/g soil in 1991 (Fig. Id). Paecilomyces spp. reached a peak incidence of
1.9 x 104 on December 14, 1989 (Fig. 1). Thus, in both years, the three fungus species
occurred at higher levels in soils cultivated under the no-till system. The differences
can be attributed to biotic and abiotic differences between the cultivation systems.
Wierenga et al. (1982) mentioned that the surface temperature amplitudes are con
siderably larger in tilled soil than in non-tilled soil. Other factors, such as the soil ca
pacity to retain water, higher organic matter, and lower temperature of soils under
minimum tillage (Vieira 1981) may have contributed to the differential prevalence of
fungi under the two cultivation systems studied.
Gaugler et al. (1989) observed that application of B. bassiana followed by tillage
was very important in achieving enhanced fungal persistence in the soil. This was
attributed to the incorporation of conidia into the soil. In the same way, no-tillage
practices can enhance persistence of entomopathogenic fungi in the surface layer of
the soil, as found in the present work. More research is needed to evaluate the effect
of the greater persistence and prevalence of fungi in no-till systems on natural pop
ulations of soybean pests as compared to conventional tillage systems. This inform
tion will be important for devising cultural practices aimed at augmenting the
natural occurrence of entomopathogenic fungi on soybean insects and, consequently,
increasing the contribution of natural pest mortality in soybean agroecosystems.
We thank Ivanilda Soldorio and Jairo da Silva for technical assistance.

SUMMARY

Cultural practices influence propagule densities of entomopathogenic fungi in
agroecosystems. An experiment was conducted in Brazil to evaluate the prevalence of







286 Florida Entomologist 77(2) June, 1994



.250 5
S20 A 7 a 33652 B
.-06
'50 .:22708 a
8 too 8 b:
0 '"
x 50
b .... an _a...
j 12/14 1/4 1/19 2/2 2/14 3/2 3/16 3/30 4/27 5/31 l 12/ll 4/12 18/12 2/1 17/1 1/2 16/2 4/3 18/3 4/4 15/4
Sampling dates Sampling dates
...No till system Till system No till system -Till system
Season 1989/90 Season 1990/91

14
S12 126 Dq

Se :- o
08 6- "/ a
2 _o .. ..... 4 2
.. b b -. .... .... b b ." ab' ..,

o 12/14 1/4 1/19 2/2 2/14 3/2 3/16 3/30 4/27 5/31 0 12/11 4/12 18/12 2/1 17/1 1/2 16/2 4/3 18/3 4/4 16/4
Sampling dates Sampling dates
.... No till system Till system .... No till system Till system

Season 1989/90 Season 1990/91


* 25

- 15 co
S20 E

8 a... a ...
i b b b b b b b
-0 --
j 12/14 1/4 1/19 2/2 2/14 3/2 3/16 3/3 4/27 5/
Sampling dates


a a F
a..'".


S... b. b
31 12/11 4/12 17/1218/12 2/1 17/1 1/2 15/2 4/3 18/3 4/4 15/4
Sampling dates


.... No till system Till system .... No till system -Till system

Season 1989/90 Season 1990/91

Fig. 1. Effect of till and no-till farming on density of colony forming units (CFUs)
of Beauveria bassiana (A, B), Metarhizium anisopliae (C, D) and Paecilomyces spp.
(E, F) in two seasons. Means within each sample date with different letters are sig
nificantly different. (P > 0.05; t-test).



Beauveria bassiana, Metarhizium anisopliae and Paecilomyces spp. in soil under no
till and conventional tillage systems. The no-till cultivation favored the prevalence of
the three fungus species when compared with the conventional tillage system.


REFERENCES CITED

CHASE, A. R., L. S. OSBORNE, AND V. M. FERGUSON. 1986. Selective isolation of the
entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae
from an artificial potting medium. Florida Entomol. 69: 285-292.
DAOUST, R. A., AND R. M. PEREIRA. 1986. Stability of entomopathogenic fungi Beau
veria bassiana and Metarhizium anisopliae on beetle-attracting tubers and
cowpea foliage in Brazil. Environ. Entomol., 15: 1237-1243.
GAUGLER, R., S. D. COSTA, AND J. LASHOMB. 1989. Stability and efficacy of Beauveria
bassiana soil inoculations. Environ. Entomol. 18: 412-417.
IGNOFFO, C. M., C. GARCIA, D. L. HOSTETTER, AND R. E. PINNELL. 1977. Vertical
movement of conidia of Nomuraea rileyi through sand and loam soils. Jour.
Econ. Entomol. 70: 163-164.
SAS INSTITUTE. 1985. Guide for personal computers. SAS Institute, Cary, N.C.







Shelly: Methyl eugenol consumption byBactrocera dorsalis 287


MOSCARDI, F., B. S. CORREA-FERREIRA, L. G. LEITE, AND C. E. O. ZAMATARO. 1985.
Incidencia estacional de fungos entomdgenos sobre populagoes de percevejos
pragas da soja, in Resultados de Pesquisa de Soja 1984/1985. p. 90.
SOSA GOMEZ, D. R., AND F. MOSCARDI. 1992. Epizootiologia: chave dos problems para
o control microbiano com fungos, in Simposio de Controle Bioldgico. Anais. p.
64 69. CNPDA-EMBRAPA [ed.]. Aguas de Lindoia, 12-16/10/92. 312 p.
STOREY, G. K., W. A. GARDNER, AND E. W. TOLLNER. 1989. Penetration and persis
tence of commercially formulated Beauveria bassiana conidia in soil of two
tillage systems. Environ. Entomol. 18: 835-839.
VIEIRA, M. J. 1981. Propriedades fisicas do solo, in Plantio direto no estado do
Parana. Circular no 23. Fundacao Instituto Agron6mico do Parana. p. 19-32.
WIERENGA, R. J., D. R. NIELSEN, R. HORTON, AND B. HEIES. 1982. Tillage effects on
soil temperature and thermal conductivity. In Predicting Tillage Effects on
Soil Physical Properties and Processes. Asa Special Publication, 44. Ed. by
American Society of Agronomy and Soil Science Society of America, Inc. Chap.
5. p. 69 90.






Scientific Notes


FRUIT OF MORRENIA ODORATA (ASCLEPIADACEAE)
AS A HOST FOR THE PAPAYA FRUIT FLY,
TOXOTRYPANA CURVICAUDA (DIPTERA: TEPHRITIDAE)


PETER J. LANDOLT
U. S. Department of Agriculture, Agriculture Research Service
1700 S.W. 23rd. Dr., Gainesville, FL 32604

The papaya fruit fly, Toxotrypana curvicauda Gerstaecker, is a pest of papaya
fruit, Carica papaya L. (Caricaceae), throughout much of the neotropics, including
southern Florida in the United States. It had previously been considered restricted
to papaya (Knab & Yothers 1914; Wolfenbarger & Walker 1974). However, it has
been reported from mango in Florida (Butcher 1952) and from additional species of
plants in Mexico (Castrejon-Ayala 1987).
I report here that papaya fruit flies have been reared from field-collected fruit of
Morrenia odorata Lindl., an asclepiad or milkweed, in Florida. Pods were collected
from climbing vines of M odorata on a palm tree in a suburban neighborhood of Sa
rasota during April 1993. These fruit were mature in size (6-7 cm long and 3-5 cm
diam) but were still green when collected, and produced latex when broken at the
stem. Fruit were held in a screened cage in a laboratory at 22 C and 45+5% RH. On
20 April 1993 thirty-four mature larvae emerged from one of two fruit collected in
Sarasota 1 April 1993. Three additional fruit collected 8 April did not yield any fly
larvae. The 34 larvae were placed in sterilized potting soil for pupation. Twelve male
and 11 female adult papaya fruit flies emerged from 19 to 22 May 1993, 30-33 days
after pupation. Papaya fruit flies have not been reported previously from this plant.
Morrenia odorata was introduced into Florida, possibly from Argentina, and is
widely distributed in the central area of the state. The utilization of such a widely oc
curring weed may conceivably promote a broader distribution of this pest insect in
Florida, and make it easier for the papaya fruit fly to infest disjunct areas of papaya
production.
Papaya fruit flies have been reared from the fruit of other Asclepiadaceae, in
Mexico. Gonolobus sorodius A. Gray is a host of T curvicauda in central Mexico (Cas
trejon-Ayala 1987, Castrejon-Ayala & Camino-Lavin 1991). Also, Baker et al. (1944)
reported talayote, or talayotillo (a vine in the milkweed family) as a host either of T
curvicauda or an undescribed species of Toxotrypana in northeast Mexico. This plant

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may be the same as the talayote of Martinez (1969), which is Gonolobus erianthus
D.C., a climbing milkweed vine found in Morelos, Mexico. The milkweed genus Mor-
renia is also a host of other species of Toxotrypana in Argentina (Blanchard 1959).
Voucher specimens are placed in the Florida State Collection of Arthropods,
Gainesville, Florida and in the National Museum of Natural History, Washington,
D.C. The plant was identified by C. Artaud of the Florida Dept. Agriculture, Division
of Plant Industry, Gainesville, Florida. I thank R. Knight for information on Asclepi
adaceae and A. L. Norrbom for information on Toxotrypana host records.


SUMMARY

Twenty three adult papaya fruit flies, Toxotrypana curvicauda Gerstaecker, were
obtained from 34 mature larvae that emerged from field-collected fruit of the milk
weed vine, Morrenia odorata Lindl. collected in Sarasota, Florida. Morrenia odorata
appears to be an alternate host for the papaya fruit fly in Florida.


REFERENCES CITED

BAKER, A. C., W. E. STONE, C. C. PLUMMER, AND M. MCPHAIL. 1944. A review of stud
ies on the Mexican fruit fly and related Mexican species. USDA Misc. Publ.
No. 531, 155 pp.
BLANCHARD, E. E. 1959. El genero Toxotrypana en la Republica Argentina (Diptera;
Trypetidae). Acta Zool. Lilloana 17: 3345.
BUTCHER, F. G. 1952. The occurrence of papaya fruit fly in mango. Florida State
Hort. Soc. Proc. 65: 196.
CASTREJON-AYALA, F. 1987. Aspectos de biologia y habitos de Toxotrypana cur
vicauda Gerst. (Diptera: Tephritidae) en condiciones de laboratorio y su distri
bution en una plantacion de Carica papaya L. en Yuatepec, Mor. BS Thesis,
Institute Polictecnico Nacional, Mexico D.F, Mexico. 88 p.
CASTREJON-AYALA, F., AND M. CAMINO-LAVIN. 1991. New host plant record for Tox
otrypana curvicauda (Diptera: Tephritidae). Florida Entomol. 74: 466.
KNAB, F., AND W. W. YOTHERS. 1914. Papaya fruit fly J. Agric. Res. 2: 447-453.
MARTINEZ, M. 1969. Las Plantas Medicinales de Mexico. 5th Edition, Justo Sierra
52. Mexico 1, D.F.
WOLFENBARGER, D. O., AND S. D. WALKER. 1974. Two major pest problems of papa
yas. Proc. Florida State Hort. Soc. 85: 384-385.


June, 1994






Florida Entomologist 77(2)


PESTICIDE RESISTANCE AND METABOLIC RATE IN
GERMAN COCKROACHES (DICTYOPTERA: BLATTELLIDAE)

MARK E. HOSTETLER, JOHN F. ANDERSON, AND CARMINE A. LANCIANI
Department of Zoology, University of Florida,
223 Bartram Hall, Gainesville, FL 32611, USA

Although physiological resistance mechanisms to most pesticides have developed
in insects, costs may be associated with these mechanisms. For example, a reproduc
tive cost is shown by resistant tobacco budworms, Heliothis virescens, which produce
significantly fewer fertile eggs (Plapp et al. 1990), and a behavioral cost is shown by
resistant Anopheles mosquitoes, which spend less time searching for hosts (Rowland
1987). An energetic cost may also be associated with resistance. For example, a com-
mon mechanism of pesticide detoxification is enzymatic breakdown of ingested or ab

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
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Scientific Notes


sorbed toxins (Soderland & Bloomquist 1990), a process that may increase energy
use as detoxification enzymes are synthesized. To determine whether an energetic
cost to pesticide resistance exists, we measured metabolic rates (02 consumption) of
resistant and susceptible German cockroaches, Blattella germanica (L.).
German cockroaches used in experiments were obtained from 2 different strains
maintained at the USDA-ARS Medical and Veterinary Entomology Research Labo
ratory in Gainesville, Florida, U.S.A. The Village Green strain is physiologically re
sistant to a variety of organophosphates and pyrethroids. Ancestors of this strain
were captured from a residential apartment complex (Village Green Apartments) in
Florida in 1987. The Orlando Normal strain is susceptible to a variety of organophos
phates and pyrethroids. Ancestors of this strain were captured from a building in Or
lando, Florida, U.S.A., in the 1940s. Cockroaches were reared in 50 x 50 x 28 cm
oblong metal tubs (temperature of 25-270C) on Purina rat chow (Purina Mills Inc.
P.O. Box 66812, St. Louis MO 63166-6812).
Metabolic-rate experiments were conducted in Gainesville during October and
November 1991 on male and female adults (gravid females without oothecae pro
truding) that had spent 0 to 2 weeks in the adult stage. Metabolic rates were mea
sured with "closed system" metabolic chambers (Vleck, 1987) following the
procedures described by Anderson et al. (1989) and Giesel et al. (1989). On the day of
each experiment, 5 male and 5 female cockroaches from each strain were placed in
dividually in 60 cm3 syringes. After the syringes were held for approximately 5 hours
in a lighted incubator at 260C, each syringe was removed, and the change in 02 con
centration was recorded and used to determine metabolic rate. Each cockroach was
weighed to the nearest 0.01 mg immediately after removal from the incubator. Sep
arate trials were conducted on 4 different days, yielding data on 20 males and 20 fe
males in both the Orlando Normal and Village Green strains.
Because sex and weight may affect metabolic rate, analysis of covariance (AN
COVA) was used to determine the influence of strain on cockroach metabolic rates in
dependent of the influence of sex and weight.
Mean metabolic rates and weights of both strains are listed in Table 1. From the
analysis of covariance, only gender (P = 0.0002) and weight (P = 0.0046), but not
strain (P= 0.38), had significant effects on metabolic rates. Thus, after the effects of
weight and strain were removed by the ANCOVA, females had a higher metabolic
rate than did males. However, after the effects of weight and sex were removed by
the ANCOVA, resistant individuals did not have a higher metabolic rate than did
susceptible individuals.
Resistant and susceptible strains had similar metabolic rates, and thus resis
tance may not have an energetic cost. Several explanations exist for the similar met
abolic rates of the two strains. (1) The Village Green cockroaches may have
physiological resistance mechanisms that do not require increased enzymatic activ
ity, e.g., altered acetylcholinesterases and sodium channels (Soderland & Bloomquist
1990). (2) The Village Green cockroaches may have detoxification mechanisms that
increase metabolic rates but require the presence of the pesticide to induce acceler
ated production of the detoxifying enzyme(s). In several studies, enzyme production


TABLE 1. MEAN METABOLIC RATES (IL 02/HR + STANDARD ERROR) AND MEAN
WEIGHTS (MG + STANDARD ERROR) OF BLATTELLA GERMANICA.

Strain Sex N Metabolic Rate Weight
Orlando M 20 34.9+ 1.2 43.3+ 0.9
Orlando F 20 64.3 +4.1 84.3+ 4.4
VG M 20 31.6+ 1.1 48.3 +0.8
VG F 20 73.4 +4.7 94.8 +4.1







290 Florida Entomologist 77(2) June, 1994


was found to increase only after exposure to the pesticide (Terriere 1983). (3) Village
Green cockroaches may have higher metabolic rates from pesticidal pressures, but
the Orlando Normal individuals may have higher than "normal" metabolic rates be
cause they have been laboratory-reared for a much longer period of time.
We thank the USDA-ARS, Medical & Veterinary Entomology Research Laboratory
for providing cockroaches. This research was in part funded by the Clorox Company.


SUMMARY

Metabolic rates, based on oxygen consumption, were determined for two strains
of German cockroaches, one resistant and one non-resistant. Both strains had simi
lar metabolic rates suggesting that resistance may not have an energic cost.


REFERENCES CITED

ANDERSON, J. F., C. A. LANCIANI, AND J. T GIESEL. 1989. Diel cycles and measure
ment of metabolic rate in Drosophila. Comp. Biochem. Physiol. 94A: 269-271.
GIESEL, J. T., C. A. LANCIANI, AND J. F. ANDERSON. 1989. Larval photoperiod and
metabolic rate in Drosophila melanogaster. Florida Entomol. 72: 123-128.
PLAPP, F. W., J. C. CAMPANHOLA, R. D. BAGWEL, AND B. F. MCCUTCHEN. 1990. Man
agement of pyrethroid-resistant tobacco budworms on cotton in the United
States. pp. 237-260 in R. T Roush and B. E. Tabashnik [eds.], Pesticide resis
tance in arthropods. Chapman and Hall, New York.
ROWLAND, M. W. 1987. Fitness of insecticide resistance. Nature 327: 194.
SODERLUND, D. M., AND J. R. BLOOMQUIST. 1990. Molecular mechanisms of insecti
cide resistance, pp. 58-96 in R. T Roush and B. E. Tabashnik [eds.], Pesticide
resistance in arthropods. Chapman and Hall, New York.
TERRIERE, L. C. 1983. Enzyme induction, gene amplification and insect resistance to
insecticides, pp. 265-298 in G. P Georghiou and T. Saito [eds.], Pest resistance
to pesticides. Plenum Press, New York.
VLECK, D. 1987. Measurement of 02 consumption, CO2 production, and water vapor
production in a closed system. J. Appl. Physiol. 62: 2103-2106.


+++++++++++++++++++++++++++++++++++++++






Florida Entomologist 77(2)


MCPHAIL TRAP CAPTURES OF ANASTREPHA OBLIQUA
AND ANASTREPHA LUDENS (DIPTERA: TEPHRITIDAE)
IN RELATION TO TIME OF DAY

EDI A. MALO AND GEORGINA I. ZAPIEN
Laboratorio de Biologia y Ecologia de Moscas de la Fruta,
Centro de Investigaciones Ecol6gicas del Sureste,
Carretera al Antiguo Aeropuerto Km. 2.5,
Apartado postal 36, Tapachula, 30700, Chiapas,
Mexico

Anastrepha Schiner is the most economically important genus of fruit flies in
Mexico (Aluja et al. 1987). These fruit flies are currently detected and surveyed with
McPhail traps, although problems with efficiency and variability of capture have
been described (Liedo 1983, Aluja et al. 1989).
A few studies of the behavior of fruit flies employing McPhail traps have been re
ported (Prokopy & Economopoulos 1975, Aluja et al. 1989). McPhail (1937) studied
the adult activity of Anastrepha ludens (Loew) in mango trees using McPhail traps

This article is from Florida Entomologist Online, Vol. 77, No. 2 (1994).
FEO is available from the Florida Center for Library Automation gopher (sally.fcla.ufl.edu)
and is identical to Florida Entomologist (An International Journal for the Americas).
FEO is prepared by E. O. Painter Printing Co., P.O. Box 877, DeLeon Springs, FL. 32130.
Tires document was created With rameMaker 40.2


June, 1994






Scientific Notes


with fermenting sugar as bait. The current work reports the capture of Anastrepha
obliqua (Macquart) and A. ludens in relation to time of day using McPhail traps
baited with proteinaceous attractant. This information may be useful in understand
ing the dynamics of fruit fly trapping.
The study was carried out in the Mazapa de Madero Valley, Chiapas, Mexico,
from 27 to 29 May and 12 to 16 June, 1986, with wild Anastrepha flies, using the
same host trees in both periods. This work was conducted before a medfly program
began to release parasitoids for biological control of Anastrepha fruit flies. The tests
were done during the period when trap captures were normally at their peak (Aluja
et al. 1989). Previous studies in Mazapa de Madero Valley have been described by
Aluja et al. (1987) and Malo (1992).
Traps were baited with a mixture of torula yeast and borax in a ratio of 4:5 (21 g)
dissolved in 300 ml of water (Lopez et al. 1971). Twelve McPhail traps were hung at
a height of 7 m in mango trees, Mangifera indica L. variety "criollo", also known as
mango de coche". The criteria for selection of trees in which to hang the traps were
mostly concerned with factors such as ease of access and the presence of mature
fruits (approximately 80% on the tree). The distance between traps was a minimum
of 100 m. Traps were hung on the trees at 0600 hours and serviced every two hours,
ending at 1800 hours. Traps were left hanging in trees throughout the night to deter
mine the possible capture during this time of day.
The contents of each trap were sieved, and the captured insects were rinsed with
clean water and placed in a 50 ml vial filled with 70% ethanol; the traps were also
rinsed and re-baited. The amount of bait used for the traps was kept constant during
each 3 to 5 day-long observation period. Captured flies were counted and identified to
species and sex using Steyskal's (1977) key. Temperatures and relative humidities
were recorded with a hygrothermograph placed in the shade of a mango tree local
ized in the center of the valley. Wind velocity was measured every two hours with an
anemometer placed in the canopy of the same mango tree (10 m height approxi
mately).
A total of 1,929 flies of the genus Anastrepha was captured, of which 56.8% were
A. obliqua, 39.8% A. ludens and 3.4% other species such as A. serpentina (Wiede
mann), A. distinct Greene, A. fraterculus (Wiedemann) and A. striata Schiner. Be
cause the catches of A. obliqua and A. ludens amounted to 96.6% of all flies caught,
the analysis was made with these species only. In earlier studies reported by Aluja et
al. (1992), A. ludens was the species most abundant, followed by A. obliqua and A.
serpentina in Mazapa de Madero Valley. Malo (1992) found that the predominant
species were A. ludens and A. obliqua. The findings obtained in this work confirmed
that the latter two species were the most abundant. Almost all the mangoes growing
in the Valley were "mango de coche", a variety highly preferred by these species
(Aluja & Liedo, 1986).
Data in Table 1 show the mean number (+ S.E.) of A. obliqua and A. ludens cap
tured per trap per 2-hour period as a function of the time of day, mean temperature,
relative humidity and wind velocity. For both species, the first flies were caught at
0800 hours; the 2-hour catch rate increased to a maximum peak between 1400 to
1600 hours, then declined from 1600 to 1800 hours. A. obliqua captures showed a sig
nificant difference in relation to time of day (F = 4.21; df = 6,49; P < 0.01). Similar
variation was observed in A. ludens (F = 6.76; df = 6,49; P < 0.01). There were no flies
trapped in the period between 1800 to 0600 hours.
Variations in temperature and wind velocity throughout the trapping period
showed a similar profile to that of capture of fruit flies in relation of time of day. The
relative humidity was high in the morning, decreased in the mid-day, and increased
again in the evening. The catches of A. ludens and A. obliqua were probably influen
ced by all these factors. McPhail trap catches have been shown to be affected by bi







Florida Entomologist 77(2)


otic factors, both of the pest and host origin, and non-biotic factors (McPhail 1937,
Neuenschwander & Michelakis 1979, Kapatos & Fletcher 1982).
Of the total number of Anastrepha fruit flies caught, 1,216 were females and 713
were males, a male:female ratio of 1:1.7. These results confirm previous reports indi
casting that McPhail traps baited with a proteinaceous feeding attractant capture
more Anastrepha females than males (Lopez & Hernandez-Becerril 1967, Houston
1981, Malo 1992). For both species, the greatest captures of females occurred at 1600
hours, whereas for males it took place at 1400 hours. However, the number of males
and females captured per trap did not differ significantly (Table 1). McPhail (1937)
found similar diurnal patterns for males and females of A. ludens, although more
males than females were caught in this case. These differences between sexes in
number caught may be the result of different volatiles produced by sugar fermenta
tion and protein baits (Malo 1992).
Finally, in spite of the disadvantages of the McPhail traps in terms of fragility,
bulkiness, and need of water (Liedo 1983), these traps can be used to capture a great
diversity of Anastrepha fruit flies. From these results, it is clear that tests with
McPhail traps can be performed between 1000 and 1800 hours, disregarding the noc
turnal period. Better knowledge of the biology and behavior of fruit flies, as well as
their preferences to different baits used, should permit the design of an improved
trap system for management of fruit flies.
The authors would like to thank Jorge Valenzuela (Instituto de Ecologia, Xalapa,
Mexico) for helpful discussions of this work and J. Hendrichs (IAEA, Vienna, Aus
tria), J. Sivinski (IABBBRL, Gainesville, Florida) and J. Cibrian-Tovar (Centro de
Entomologia y Acarologia, Colegio de Postgraduados de Chapingo, Texcoco, Mexico)
for helpful comments on the manuscript. Technical assistance was provided by
Miguel Angel Guzman, Gerardo Hernandez-Rojas and Rufino Vargas.


SUMMARY

McPhail trap capture of Anastrepha fruit flies in relation to time of day was stud
ied. Six species were caught, with Anastrepha obliqua and Anastrepha ludens being
the predominant species. The first capture was obtained at 0800 hours and catches
increased throughout the day up to a maximum between 1400 and 1600 hours. More
females than males of both species were captured.


REFERENCES CITED

ALUJA, M., AND P. LIEDO. 1986. Future perspectives on integrated management of
fruit flies in Mexico, pp. 12-48 in M. Mangel, J. R. Carey and R. Plant [eds.].
Pest Control: operation and systems analysis in fruit fly management. Proc.
NATO advanced workshop. Springer Verlag. New York.
ALUJA, M., M. CABRERA, E. RIos, J. GUILLEN, H. CELEDONIO, J. HENDRICHS, AND P.
LIEDO. 1987. A survey of the economically important fruit flies (Diptera: Te
phritidae) present in Chiapas and a few other fruit regions in Mexico. Florida
Entomol. 70: 320-329.
ALUJA, M., M. CABRERA, J. GUILLEN, H. CELEDONIO, AND F. AYORA. 1989. Behaviour
of Anastrepha ludens, A. obliqua and A. serpentina (Diptera: Tephritidae) on a
wild mango tree (Mangifera indica) harbouring tree McPhail traps. Insect Sci.
Applic. 10: 309-318.
ALUJA, M., J. GUILLEN, P. LIEDO, M. CABRERA, E. RIos, G. DE LA ROSA, H. CELE
DONIO, AND D. MOTA. 1990. Fruit infesting tephritids (Diptera: Tephritidae)
and associated parasitoids in Chiapas, Mexico. Entomophaga. 35: 3948.
HOUSTON, W. W. K. 1981. Fluctuations in number and the significance of the sex ra
tio of the Mexican fruit Anastrepha ludens caught in McPhail traps. Entomol.
exp. & appl. 30: 140-150.


June, 1994








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