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Seven populations of Toxoptera citricida (Kirkaldy) were sampled in central Florida sweet orange groves in 2001. All populations contained individuals that accepted cotton seedlings as a host in a no-choice situation; many of these matured and deposited nymphs that also developed and became reproductive on the same plant. Significant differences were noted among populations with respect to the proportion of nymphs accepting, maturing, and ultimately reproducing on cotton. Differences in aphid survival were largely a function of differences in host plant acceptance, rather than differential mortality on the plant. A significant proportion of the apterous adults maturing on cotton abandoned the plant without reproducing. Second and third instars transferred from laboratory colonies maintained on sweet orange were more accepting of cotton than were either first or fourth instars. Apterous adults accepted cotton at rates similar to second and third instars. Alate adults settled on cotton seedlings in greenhouse choice experiments and probed the plants, but none deposited nymphs. Alatae that matured on cotton readily accepted citrus for feeding and reproduction. It is concluded that cotton may be useful as a factitious host plant for rearing T. citricida in the laboratory, but field planted cotton is unlikely to serve as a reservoir of the aphid in regions where citrus is grown.
Insecticidal effects of an encapsulated formulation of lambda-cyhalothrin on the southern green stinkbug Nezara viridula (L.) and one of its predators, Podisus maculiventris (Say), were investigated in the laboratory. Both pentatomids were exposed to the insecticide via contaminated drinking water and by residual contact. Nymphs and adults of N. viridula were more susceptible to the insecticide than nymphs of P. maculiventris, both by ingestion and contact exposure. For the respective ways of exposure, LC50 values calculated for P. maculiventrisfourth instars were 30-190 times and 3-13 times higher than those of N. viridulafourth instars. Insecticidal activity of the pyrethroid by ingestion was 6-10 times greater against nymphs of N. viridula than against adults of the pest. In both the ingestion and residual contact experiments, nymphs of P. maculiventris recovered from initial knockdown. LC50 values for predator nymphs increased 1.7- to 2.7-fold between 24 and 48 h after the start of the experiment. Recovery from knockdown was not observed in N. viridula. The data from the current laboratory study suggest that encapsulated lambda-cyhalothrin may be effective for controlling the southern green stinkbug with little adverse effects on the predator P. maculiventris, but field experiments are needed to confirm this. Possible reasons for the differential toxicity of the insecticide to both pentatomids are discussed.
We tested whether reproductive tactics of a univoltine insect can be predicted by local ecology, specifically mean length of the frost free period (FFP) as a measure of the potential active season. We measured reproductive tactics and longevity for populations of the lubber grasshopper Romalea microptera (Beauvois) from Miami, Florida (FL; 365 days FFP), Lydia, Louisiana (LA; 280 days FFP), and Athens, Georgia (GA; 224 days FFP). Differences in local climate led us to predict that GA grasshoppers will have shorter interclutch intervals, fewer clutches, and shorter lifespan than FL grasshoppers, with LA grasshoppers intermediate in these traits. When reared in a common laboratory environment, longevity, total reproductive period, and number of clutches produced were not clearly related to FFP. Longevity and reproductive period of LA grasshoppers were significantly less than those of FL grasshoppers, and number of clutches produced by LA grasshoppers was less than that for the FL or GA grasshoppers. First interclutch interval was significantly greater for LA than for GA grasshoppers. Our data suggest that phylogenetic relationships among populations may be a better predictor of reproductive tactics in this species.
The host foraging behavior of the larval parasitoid Diachasma alloeum (Muesebeck) (Hymenoptera: Braconidae) from natural populations was directly observed in a highbush blueberry, Vaccinium corymbosum L., plantation. More D. alloeum were observed alighting on blueberry fruit clusters infested with Rhagoletis mendax Curran larvae than were observed alighting on uninfested blueberry fruit clusters 80 cm away. Approximately equal numbers of D. alloeum alighted on uninfested blueberries that were mechanically damaged versus undamaged. The majority of D. alloeum females were attracted to host-infested blueberries 15 to 21 days after R. mendax females had oviposited into fruit. Female D. alloeum spent more time alighting on R. mendax-infested blueberry fruit clusters than on uninfested blueberry clusters 80 cm away. There was no difference in the duration of time spent by D. alloeum on mechanically damaged versus undamaged uninfested blueberries. The data herein are an initial step toward elucidating the cues mediating microhabitat selection by D. alloeum in blueberries.
The population dynamics (in terms of seasonal development) of Gryllotalpa africana Palisot de Beauvois was documented for the first time in South Africa. An irritant drench (soapy water solution) was used to quantify life stage occurrence on turfgrass over a one-year period. Oviposition took place from early October (spring), with eggs incubating for approximately three weeks. Nymphs reached the adult stage from March (late summer) and most individuals overwintered in this stage. Adult numbers peaked in early September (early spring), declining through spring. G. africana was therefore univoltine in the study area. The adult population was female biased in spring. The smallest nymphs and adults (in relation to mean length) were collected in December (early summer), while the smallest nymphs (in relation to mean length) occurred in November (late spring).
The ponerine ant Odontomachus relictus n. sp. is described from specimens collected in scrub and sandhill habitats on several ancient sand ridges in Florida. It appears to be a relict species from dry periods in the Pleistocene. Workers are similar to the western species O. clarus Roger, but males of the two species are strongly divergent. Keys and natural history notes are provided for workers and males of the four Odontomachus species known from the U.S. Examination of males might help clarify the taxonomic status of Odontomachus of Central and South America.
Formosan subterranean termite, Coptotermes formosanus Shriaki, is a serious pest of structures in portions of United States. A 467-bp region of the mtDNA 16S rRNA gene was subjected to DNA sequencing from 12 Coptotermes species, including 64 populations of C. formosanus. Genetic diversity among species ranged from 1.8% to 7.0%, with C. formosanus at least 3.0% divergent to the other Coptotermes taxa. No genetic variation was detected among the C. formosanus populations for this marker making it ideal for diagnostics. Comparison of nucleotide sequence of mitochondrial rRNA 16S was used to design polymerase chain reaction (PCR) primers specific for C. formosanus. The diagnostic assay consists of two independent PCR runs of the 16S primer pair along with the C. formosanus primer set. PCR product from samples that are not C. formosanus can be subjected to DNA sequencing and compared with the database of termite 16S sequences on GenBank for identification. This technique provides a non-morphological method to identify field collected termites and may facilitate future quarantine programs for C. formosanus.
Sequencing of a portion of the mitochondrial DNA 16S gene was undertaken to determine genetic variation and distribution of Reticulitermes in Oklahoma. From 16 Oklahoma counties, 43 R. flavipes, four R. hageni, one R. virginicus, and seven R. tibialis samples were collected, identified and subjected to DNA sequencing. No genetic variation was observed in R. virginicus, while two haplotypes were observed in R. hageni, four in R. tibialis, and 10 for R. flavipes. Among the 10 R. flavipes haplotypes, nine nucleotides were variable and genetic variation ranged from 0.2 to 1.4%. Phylogenetic analysis revealed several minor relationships within R. tibialis and R. flavipes; however, there was no apparent geographical association to the haplotypes. The high amount of genetic variation, but a lack of geographically distinct haplotypes in R. flavipes, indicate that this termite species has been distributed randomly in Oklahoma by humans due to its association with structures.
Two species of the Asian genus Greenidea have been introduced into the United States, Greenidea ficicola Takahashi and Greenidea psidii van der Goot. Synonymy confusion between Greenidea formosana (Maki) and G. psidii is resolved in favor of G. psidii. Both species colonize Ficus spp., and G. psidii colonizes a few other plants, mostly in Myrtaceae. The two species can be distinguished by the ornamentation on the siphunculi on the apterous forms, and usually also by the arrangement of rhinaria on antennal segment III of the alate forms.
We describe all immature stages, particularly the previously undescribed instars, of Fopius arisanus (Sonan) (Hymenoptera: Braconidae), an egg-pupal parasitoid of tephritid fruit flies. This is essential for quality control in mass rearing programs and for physiological studies of host-parasite interactions. Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) eggs were parasitized for 24 h and serial collections of hosts were made every 24 h until adults emerged. Immature wasps were dissected from hosts and their mouthhooks and body dimensions measured. Scatter plots of the above measurements and scanning electron microscopy indicated that there are three instars. This contrasts with the four instars previously reported. There appears to be no true fourth instar because the stage immediately following the second instar is indistinguishable from that preceding the prepupal stage.
A severe infestation of adult host-seeking black flies (Diptera: Simuliidae) occurred in west central Florida during 1998. Collections from stationary suction traps in Pasco County revealed the presence of large numbers of Simulium slossonae Dyar and Shannon. This species peaked in traps during March (avg >40 per trap) with a lesser secondary peak in October (avg ≈5 per trap). Moreover, during March, some suction traps had collected as many as 2,000 black flies for the month. It was believed that the spring outbreak of S. slossonae was the result of above average precipitation associated with an El Niño event. Precipitation produced by this weather system during the winter of 1997/1998 provided a continuous source of rain-swollen ditches, streams, and creeks for rapid larval and adult production the following spring. Conversely, 1999 resulted in rainfall deficits of 1.5 cm to nearly 7.0 cm below normal. During that year, adult black fly populations were almost nonexistent (≤3 black flies collected per trap month) compared with collections obtained the previous year.
A new species of Cholula (Myodochini) from Jamaica is described. This represents the first record of this genus for the Caribbean. Cholula minuta can be differentiated from other species of the genus mainly by its size. It is one of the smallest species described to date, being similar in size only to C. parvus, but C. minuta is unicolorous, while C. parvus has a mixture of black, brown and white coloration.
J. H. Frank, S. Sreenivasan, P. J. Benshoff, M. A. Deyrup, G. B. Edwards, S. E. Halbert, A. B. Hamon, M. D. Lowman, E. L. Mockford, R. H. Scheffrahn, G. J. Steck, M. C. Thomas, T. J. Walker, W. C. Welbourn
Twenty four epiphytic bromeliads belonging to four species (Tillandsia fasciculata Swartz, T. recurvata (L.), T. setacea Swartz, and T. utriculata L.) were collected in Sarasota County, Florida, in October-November 1997. Macroscopic invertebrate animals were extracted from each by washing in water, filtering, and preserving in 75% ethanol. Plant sizes were measured in several ways, and their substrate was identified. Invertebrates were sorted, counted, and identified as far as possible to the species level. Two species (T. fasciculata, T. utriculata) that impound water in their leaf axils housed aquatic dipteran larvae and pupae (Psychodidae, Culicidae, Ceratopogonidae, Chironomidae, Muscidae, and Aulacigastridae) representing 7 species in 6 genera. Only T. utriculata had a clear relationship between plant size and number of invertebrates, which was steeper when only aquatic insect larvae were counted. Plants of all four species housed terrestrial invertebrates, representing minimally an additional 82 species in 75 genera and 63 families, very few of which are known to have an obligate relationship with bromeliads, but showing that these plants support a diverse invertebrate fauna. The presence of ant nests in some bromeliads complicated analysis. Such a list of terrestrial invertebrates, identified to the species level, has not before been compiled for bromeliads in Florida. Some collaborating taxonomists obtained specimens of species that they could not identify, including probably undescribed species.
Two parasitoid species, Amitus hesperidum Silvestri and Encarsia opulenta (Silvestri), were released in an augmentative program to control citrus blackfly, Aleurocanthus woglumi Ashby, in the citrus growing areas of southern Texas. Releases were made with laboratory-reared and field insectary parasitoids. Six citrus groves were closely monitored, and evaluations made during and after releases suggested that both parasitoid species became reestablished and exerted control over pest populations. Dissection of citrus blackfly immatures led us to suggest that E. opulenta increased in larger numbers than A. hesperidum, and that a stable host-natural enemy relationship became established.
We reared newly hatched Phaon Crescent butterfly larvae to the adult stage on a completely artificial diet. About 37% of first instars survived to the adult stage. Addition to the diet of freeze-dried host plant leaves equal to 10% by weight of dry ingredients produced up to 66% survival to the adult stage. Survival of larvae and production of adults on the artificial diet without host plant leaves was increased to equal that of diet with host plant leaves by adding 5% glucose or 5% Beck’s salt mix. Although the ovaries of females produced on host-free artificial diet appeared to be mature at emergence and contained mature-looking eggs, we never obtained viable eggs from them. In contrast, females produced on the artificial diet containing at least 10% by weight of freeze-dried host plant leaves laid viable eggs, and four successive generations were reared on the artificial diet with 10% freeze-dried host plant leaves. Males produced on the artificial diet without host plant tissue displayed abnormalities in the shape of the testes and parts of the vas deferentia, compared to males reared on the diet with freeze-dried host leaves or on living host plants. The role of host plant tissue in nutrition and reproduction of both male and female Phaon crescents remains to be determined.
We investigated the larval dipteran fauna of artificial and natural containers, sewage treatment plants, and storm drains in the Florida Keys. Mosquitoes collected were Aedes aegypti, Ae. albopictus, Anopheles crucians, Culex atratus, Cx. nigripalpus, Cx. peccator, Cx. quinquefasciatus, Deinocerites cancer, Ochlerotatus taeniorhynchus, and Wyeomyia vanduzeei, as well as an unidentified Culex (Melanoconion) species and an unidentified Anopheles species. Other Diptera collected included a chironomid species in the Chironomus decorus Johannsen group; the filter fly, Clogmia albipunctata; an undescribed psychodid in the genus Austropericoma; a ceratopogonid midge, Dasyhelea pseudoincisurata; and a phorid fly, Megaselia scalaris.
One hundred faba bean (Vicia faba L., Fabales: Fabaceae) accessions from the USDA-NSSL Seed Repository in Prosser, WA were grown outdoors in southern Florida from December 2000 through April 2001 and October 2001 through April 2002 to both evaluate their potential as a forage crop and to initiate selections of superior genotypes. Insect herbivores and their predators were observed for feeding associations and collected for identification throughout the two seasons of trials. Sixty-one species of insect herbivores and nectaring predators and parasitoids were observed feeding on or were captured on faba bean leaves, stems, flowers, extra-floral nectaries or pods. Additionally, thirty-two species of predacious and parasitic insects were observed eating herbivorous insects or captured while searching for prey or hosts on faba beans plants. The most significant damage was caused by large populations of Aphis craccivora Koch (Hemiptera: Aphidae) that fed on terminals and young leaf and stem tissue. Six Coccinellidae species fed upon aphids and reproduced on the crop. Pods were damaged by reproducing populations of Leptoglossus phyllopus (L.) (Hemiptera: Coreidae) and Nezara viridula (L.) (Hemiptera: Pentatomidae).
For more than 50 years, two exotic ant species, Linepithema humile (Mayr) and Pheidole megacephala (F.), have been battling for ecological supremacy in Bermuda. Here we summarize known ant records from Bermuda, provide an update on the conflict between the dominant ant species, and evaluate the possible impact of the dominant species on the other ants in Bermuda. We examined ant specimens from Bermuda representing 20 species: Brachymyrmex heeri Forel, B. obscurior Forel, Camponotus pennsylvanicus (De Geer), Cardiocondyla emeryi Forel, C. obscuriorWheeler, Crematogaster sp., Hypoponera opaciceps (Mayr),H. punctatissima (Roger), L. humile, Monomorium monomorium Bolton, Odontomachus ruginodisSmith, Paratrechina longicornis (Latreille), P. vividula (Nylander), P. megacephala, Plagiolepis alluaudi Forel, Solenopsis (Diplorhoptrum) sp., Tetramorium caldarium Roger, T. simillimum (Smith), Wasmannia auropunctata (Roger), and an undetermined Dacetini. Records for all but three (H. punctatissima, P. vividula, W. auropunctata) include specimens from 1987 or later. We found no specimens to confirm records of several other ant species, including Monomorium pharaonis(L.) and Tetramorium caespitum(L.). Currently, L. humile dominates most of Bermuda, while P. megacephala appear to be at its lowest population levels recorded. Though inconspicuous, B. obscurior is common and coexists with both dominant species. Paratrechina longicornis has conspicuous populations in two urban areas. Three other ant species are well established, but inconspicuous due to small size (B. heeri, Solenopsis sp.) or subterranean habits (H. opaciceps). All other ant species appear to be rare, including at least one, O. ruginodis, which was apparently more common in the past.
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