Population behaviour of the southern green stink bug,Nezara viridula,with special reference to the developmental stages of early-planted paddy

Population behaviour of adults and 5th-instar nymphs of Nezara viridula L. was analysed by means of the marking-and-recapture method in an early-planted paddy field. The field contained five varieties of rice which differend in growth states. It was estimated that a total of more, than 7,000 adults of the first generation, in which at least 3,000 were females, invaded the field from early July to middle August. Egg-mass census data, however, indicated that only 10 per cent or less of the females participated in egg-laying. This was largely due to the, low rate of adult survival. The adults preferred younger plants, for both feeding and oviposition. The method described byIwao et al. (1966) permitted estimate that 3,300–3,400 of the 5 th-instar nymphs and 1,100–1,200 of the adults of the second generation were produced from 298 egg-masses (25, 700 eggs); while 95–6 per cent of the individuals were thought to have died before reaching adulthood. Most of the 5 th-instar nymphs moved less than 4 m in three days as long as the condition of food plants remained suitable, but they tended to move more towards younger plants when those on which they lived became too mature. The apparent survival rate of the second generation adults was very low, probably due both to a rapid emigration and a high mortality of newly-emerged adults.     

Seasonal changes in fat content,form, state of gonads and length of adult life in the sycamore aphid,Drepanosiphum platanoides (Schr.)

• 1 Even when reared under similar conditions of crowding and nutrition, first and second generation adult sycamore aphids differ in their morphology and physiology. Second generation adults have a smaller abdomen, a longer gut, greater fat reserves, less developed gonads, a longer reproductive diapause and live longer than first generation aphids.
• 2 Second generation nymphs reared in isolation develop into adults which have less well-developed gonads but a reproductive delay similar to that of first generation adults.
• 3 Crowding of second generation adults prolongs the reproductive diapause.

     

Natural food requirements of the large milkweed bug,Oncopeltus fasciatus (Hemiptera: Lygaeidae), and their relation to gregariousness and host plant morphology

Summary The life ofOncopeltus fasciatus centers on the seeds of milkweeds (Asclepiadaceae,Asclepias syriaca in this study). Adults reproduce prolifically on these seeds, but they engage in only half as much copulation and lay only a few eggs when fed milkweed buds and flowers instead. They can not maintain body weight on a diet of just vegetative plants. Vegetative shoots support only slow growth and produce adults only in certain circumstances.Seeds are often inaccessible to nymphs in the three youngest instars, since their mouthparts are too short to penetrate the thick walls ofA. syriaca pods. Nymphs feeding from the outside of closed pods develop more slowly than those feeding on exposed seeds. Since mortality occurs at a constant rate, slow growth results in fewer surviving. Even adults, which can feed through almost any pod wall, prefer to feed where it is thinnest. Thus the pod wall effectively protects many seeds from this herbivore.Nymphs in larger groups (20 individuals) suffer much lower mortality than those in small groups (5 individuals), when they are feeding from the outside of closed pods. However, group size does not affect survival when nymphs are fed seed. Gregariousness apparently partly compensates for the less nutritious diet attainable from the outside of pods and thus is related to this bug's extreme specialization of diet.Other characteristics coordinated with the seed requirement include the timing of migration and egg laying, the female's choice of oviposition site, and the nymphs' balanced tendencies to be sedentary and to disperse. Among the milkweeds, such traits as thick pod walls, wide spacing, and rapid seed dispersal could have been selected for by a seed predator such asO. fasciatus.As a specialist and a probable agent of such selection,O. fasciatus is committed to keeping up with changes in its host plant. This requires maintaining some flexibility in its behavior or gene pool. K. Evans (personal communication) finds thatO. fasciatus in California onA. fascicularis lays eggs so early that the first nymphs hatch as the first flowers are opening. In that more equitable climate and on that host, adult reproduction is apparently not as dependent on pods being present in the colonized patch, and the nymphs must rely on non-seed food more often than they do in the association withA. syriaca in the East and Midwest. This very specialized species apparently retains enough adaptability to exploit milkweeds of various forms and phenologies living in a wide range of climates. This adaptability could promise its continued success in the coevolutionary race with its host plants.     

Availability of unfertilised eggs increases the fitness of nymphal crickets (Gryllidae)

1. Female insects of many species lay both fertilised and unfertilised eggs, with the latter accounting for up to 50% of the total number laid. These unfertilised eggs do not hatch and so their relevance is unclear. 2. In the present study, it was found that nymphs of the cricket Velarifictorus aspersus ate unfertilised eggs regardless of whether there was other food available. This provision enabled nymphs to develop successfully when no other food was provided, and to gain additional body mass when other food was available under crowded conditions. These results suggest that unfertilised eggs have an important role in the survival and development of nymphs. 3. Nymphs preferred to eat unfertilised rather than fertilised eggs, suggesting that they may have the ability to distinguish between these two types of eggs. 4. Crowding promoted feeding on unfertilised eggs and accelerate nymphal development, suggesting that greater food consumption accounts for faster growth under grouped conditions.     

蒙古寒蝉成、若虫触角形态及若虫龄期判别研究（半翅目：蝉科）

对蒙古寒蝉若虫与成虫的触角感器进行了研究,并结合不同龄期若虫触角的形态特征,采用Dyar法则与“头宽—龄期”的回归曲线验证,初步断定蒙古寒蝉若虫具有4个龄期。不同龄期若虫与成虫的触角形态差异显著,触角感器的种类、数量和分布也明显不同,其差异或与若虫和成虫的生态位不同密切相关。     

A test of the relationship between cuticular melanism and immune function in wild‐caught Mormon crickets

Cuticular melanism and innate immune parameters can share common physiological pathways in insects, and this functional connection may contribute to the maintenance of insect colour polymorphisms. However, evidence linking colouration and immune function has been equivocal, particularly when tested in wild populations. The present study investigates phenotypic links between colouration and immune function in migratory Mormon crickets (Anabrus simplex, Haldeman), in which juveniles occur in conspicuous colour variants but mature to become uniformly melanic adults. Wild‐caught insects are used to evaluate the relationship between juvenile colouration and three immune parameters: encapsulation ability, lysozyme‐like activity and phenoloxidase activity. As nymphs, brown crickets are better able to encapsulate an inert implant introduced into the haemocoel than green crickets, although the difference is slight and ceases after they all become darkly‐coloured adults. By contrast, adults that develop from brown nymphs have a higher basal phenoloxidase activity than those that develop from green nymphs, regardless of the fact that all adults are brown. Intrinsic factors other than colouration exert larger effects on immunity: males show stronger encapsulation responses but lower phenoloxidase activity than females, suggesting a sex‐specific trade‐off between these two immune parameters, and adults exhibit higher immune function than nymphs. In summary, modest support is found for a correlation between cuticular melanism and increased immune function in wild Mormon crickets. Additional intrinsic factors such as developmental stage and sex appear to interact with colouration and have a more substantial connection to immune function in the wild.     

Biology of Tupiocoris cucurbitaceus (Hemiptera: Miridae), a predator of the greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) in tomato crops in Argentina

The predator Tupiocoris cucurbitaceus is frequently found attacking Trialeurodes vaporariorum in greenhouses without pesticide applications in Argentina. The objective of these studies was to evaluate some biological characteristics of this species fed on three types of diet (whitefly nymphs, Sitotroga cerealella eggs and a mix of both) and on two host plants (tomato and tobacco), under controlled experimental conditions. Preimaginal developmental time for female and male bugs was shorter in the presence of whiteflies than with only moth eggs. Females lived longer when they ate only whitefly nymphs compared to a mixed diet or only moth eggs. The amount of adult descendants was greater when bugs could eat whiteflies, regardless of the presence of S. cerealella. Embryonic development time, male longevity and sex proportion were not affected by the diet or the host plant. Prey consumption was evaluated for three T. cucurbitaceus life history stages (fourth/fifth instar nymphs, female and male adults) on two types of prey (whitefly nymphs and S. cerealella eggs). On tomato, females were more voracious than males and nymphs. On tobacco, adults and nymphs consumed more S. cerealella than T.vaporariorum nymphs, but again, bug females preyed more than males and nymphs. Results demonstrate that T. cucurbitaceus can survive, develop and reproduce normally using both T. vaporariorum and S. cerealella eggs as prey on tobacco or tomato plants. This information can be useful for managing this predator against T. vaporariorum through conservative or augmentative biological control strategies.     

Efficacy of multiple biocontrol agents against the sweet potato whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) on tomato

Abstract: Biological control provides an environmentally harmonious and potentially stable management tactic to combat noxious pests such as Bemisia tabaci, notorious for its resistance to synthetic pesticides. Bioassays conducted under control chamber conditions integrating applications of the parasitoid Encarsia formosa, reared for 20 years on Trialeurodes vaporariorum, and the fungus Verticillium lecanii on the third‐fourth instar nymphs of B. tabaci on tomato, showed a comparable effect between the parasitoid‐fungus combined treatment and the fungus treatment alone (70.7% vs. 70.4%). Analysis of our results indicates antagonism between the two biocontrol agents related to the parasitoids’ ability to discriminate between infected and healthy B. tabaci nymphs. The parasitoid treatment alone produced 36.3% mortality, with no mortality in the distilled water controls. The behavioural performance of the parasitoid could have either genetic or environmental causes. Bioassays studying the feeding habit of the imported mirid predator Macrolophus caliginosus (adults) and the indigenous mirid Camptotylus reuteri (nymphs and adults) on eggs, or early second instar nymphs of B. tabaci, and choice preference tests indicated a significant difference in feeding between M. caliginosus and C. reuteri. There was no significant difference in percentage feeding of M. caliginosus on eggs (2.2%) or second instar nymphs (8.0%). There was a significant difference in feeding of M. caliginosus adults (18.6%) when offered eggs and second instars in the same arena compared with eggs or second instars offered separately. These results could be attributed to the biological behaviour of the predator having a type III functional response. Studies with the local C. reuteri species showed no significant difference in adult and nymphal consumption on second instars of B. tabaci compared with nymphs on eggs. However, C. reuteri adults fed less on eggs compared with nymphs. This local predatory species appears to be more efficient than M. caliginosus in feeding on particular stages of B. tabaci without depending on prey density. This is further supported by the low consumption of both adults and nymphs in the choice test (4% and 2.3%, respectively) compared with M. caliginosus adults (18.6%).     

Electroantennogram responses of aphid nymphs to plant volatiles

Abstract. Electroantennogram (EAG) responses of immature aphids were investigated for 30 plant volatile compounds in third‐ and fourth‐stadium nymphs of the black bean aphid, Aphis fabae. The nymphs were destined to develop into adult alate (winged) virginoparae. The EAG response profiles were similar to those previously reported in the adults. Among the compounds tested, hexanonitrile elicited the largest EAG responses in both nymphal stadia, corresponding to previously reported results with adults. Six‐carbon aliphatic compounds showed relatively higher EAG activities in the nymphs but, in contrast, (E)‐2‐hexenal, benzaldehyde, α‐pinene and β‐pinene, and citronellal elicited relatively smaller EAG responses in nymphs than adults. Although overall EAG response profiles were similar between the third and the fourth stadia for the majority of the volatiles, four aldehyde compounds, hexanal (E)‐2‐heptenal, 2‐hydroxybenzaldehyde and citronellal, showed relatively higher EAG activities in the third than in the fourth stadium. The present study indicates that aphid nymphs possess a functional olfactory receptor system before the antennae are fully developed morphologically and physiologically.     

Habitat selection in rock pool corixids: the effect of local density on dispersal

The corixid species breeding in temporary rock pools of Baltic archipelago live in a highly fragmented and unpredictable habitat. Shallow rock pools can dry out and be refilled repeatedly during a summer causing high mortality of immatures. In deeper pools, young nymphs face intense competition by older stages including cannibalism. The adult corixids move frequently between rock pools and are thus able to use currently available habitat for reproduction. In this dispersal behaviour, the ability to assess the local population density and hence select the more suitable low density patches would be advantageous. We studied the effect of local population density on the frequency of dispersive flights of Arctocorisa carinata (Sahlberg) and Callicorixa producta (Reuter) experimentally, using rock pools from which nymphs of both species were removed. The dispersal rates of marked C. producta adults were significantly lower from experimental rock pools than from normal density controls, leading to a concentration of C. producta adults in the experimental rock pools. Indications of immigration rate differences between the experimental and control pools were also observed. No clear differences were found in the superior competitor A. carinata.     

Size-dependent survivorship in the web-building spiderAgelena limbata

Summary Stage-specific mortality rates and mortality factors for the web-building spiderAgelena limbata, which is suggested to be food-limited, were studied, and the relationship between body size of spiders and survivorship for instar 3 to adults was examined. The mortality rate of the egg sac stage including eggs, deutova (prenymphal stage), and overwintering instar 1 nymphs was low. The low mortality of this stage was partly due to maternal care that reduced the mortality caused by predation and/or abiotic factors. From emergence of instar 1 nymphs from egg sacs to reproduction, the stagespecific mortality rates were almost constant, 32–47%, and the time-specific mortality rates were also constant. These results suggest a Deevey (1947) type II survivorship curve inA. limbata, in contrast to other reports on the wandering or burrowing spiders which suggested type III curves. Important mortality factors for nymphs and adults were parasitism by an ichneumonid wasp and predation by spiders. There were great variations in body size (carapace width) ofA. limbata in the field. Smaller individuals survived at a lower rate to the next stage than larger individuals. This tendency was clearer for the population living under poorer prey availability.A. limbata was unlikely to starve to death in the field because every stage ofA. limbata could survive starvation for a long time in the laboratory, 22–65 days on average. I suggest that the size-dependent survivorship of this spider is associated with vulnerability of smaller individuals to parasitism and predation.     

Effects of a juvenile hormone analog, pyriproxyfen, on the apterous form of Lipaphis erysimi

Effects of a juvenile hormone analog, pyriproxyfen, on various developmental stadia of the apterous form of the turnip aphid, Lipaphis erysimi (Kaltenbach), were bioassayed at three concentrations (50, 100, and 150 mg [AI]/l) in the laboratory. Supernumerary-molted nymphs with 1-3 extra molts were found when the first three nymphal instars were treated, and all these nymphs died prematurely. In contrast, all treated fourth instar nymphs molted normally to adults. The longevity of all pyriproxyfen-treated L. erysimi nymphs and adults and the fecundity of treated adults were reduced by 50%. Higher concentrations of pyriproxyfen (100 and 150 mg [AI]/l) caused sterility in adults from treated fourth instars; whereas the lowest concentration (50 mg [AI]/l) did not cause any adult sterility. A majority of adults from treated fourth instars and treated adults produced normal nymphs, and some adults produced dead nymphs with normal appendages or dead and deformed nymphs without any appendages. Normal nymphs produced by the adults from treated adults or treated at fourth instars developed more slowly from first instar to adult than the water-treated nymphs, and all adults in the new generation apparently reproduced normally. The potential role of pyriproxyfen in a vegetable aphid IPM program was discussed.     

Effect of European wheat striate mosaic, acquired transovarially, on the biology of its planthopper vector Javesella pellucida

The proportion of infective nymphs of Javesella pellucida in the progenies of female vectors of European wheat striate mosaic (EWSM) disease ranged from 85 to 96%; 71% of these nymphs infected plants within one week of hatching. Inbreeding for one or two generations significantly decreased the viability of J. pellucida eggs, but EWSM had no effect on the viability of eggs laid by inbred or outbred vector lines. However, EWSM acquired transovarially usually increased the mortality of J. pellucida nymphs by 13 to 17%, although mortality was as high as 30% in some vector lines. EWSM, acquired transovarially for two generations, decreased the longevity of adult males and females of J. pellucida by 14%. Inbreeding for two generations resulted in 40% increase in the mortality of nymphs and more than 50% reduction in the longevity of adults.     

Delivery of dsRNA through topical feeding for RNA interference in the citrus sap piercing‐sucking hemipteran,Diaphorina citri

RNA interference (RNAi) is a powerful means to study functional genomics in insects. The delivery of dsRNA is a challenging step in the development of RNAi assay. Here, we describe a new delivery method to increase the effectiveness of RNAi in the Asian citrus psyllid Diaphorina citri. Bromophenol blue droplets were topically applied to fifth instar nymphs and adults on the ventral side of the thorax between the three pairs of legs. In addition to video recordings that showed sucking of the bromophenol blue by the stylets, dissected guts turned blue indicating that the uptake was through feeding. Thus, we called the method topical feeding. We targeted the abnormal wing disc gene (awd), also called nucleoside diphosphate kinase (NDPK), as a reporter gene to prove the uptake of dsRNA via this method of delivery. Our results showed that dsRNA‐awd caused reduction of awd expression and nymph mortality. Survival and lifespan of adults emerged from treated nymphs and treated adults were affected. Silencing awd caused wing malformation in the adults emerged from treated nymphs. Topical feeding as a delivery of dsRNA is highly efficient for both nymphs and adults. The described method could be used to increase the efficiency of RNAi in D. citri and other sap piercing‐sucking hemipterans.     

Bottom-up Mediation of an Ant-Membracid Mutualism: Effects from Different Host Plants

The relationship between the membracid, Publilia modesta, and the tending ant, Formica obscuripes, was either a mutualism or commensalism depending on the host plant species. Experimental manipulation of the presence of ants in two different years indicated that the presence of ants had a positive effect on nymph numbers on both host plants, Chrysothamnus viscidiflorus and Wyethia spp. However, Wyethia spp. senesced before membracid nymphs reached adulthood, causing extensive mortality of membracids. In contrast, C. viscidiflorus plants senesced after nymphs had developed into adults. The increased number of nymphs in the presence of ants translated into more new adults on C. viscidiflorus, but not on Wyethia spp. Poor host plant choices may render the presence of ants irrelevant for such insects on some host plants. Being a host plant generalist may lead to significant variability in the outcomes of mutualistic interactions. Co-ordinating editor: N. Yamamura     

Survival and reproduction of Liposcelis paeta (Pearman) (Psocoptera: Liposcelididae) when irradiated by electron beams

Electron beam irradiation has been evaluated for the survival and reproduction of Liposcelis paeta Pearman (Psocoptera: Liposcelididae). All effects increased with increasing doses from 50 to 1000 Gy when the electron energy was 2 MeV. Eggs were unable to develop into adults following a dose of 100 Gy. Complete (100%) mortality was achieved about 5 weeks after adult emergence from nymphs irradiated at 300 Gy, whereas 100% mortality of adults was achieved 9 weeks after irradiation at 300 Gy. The fecundity was greatly reduced to 1.82% of that of control when L. paeta adults were irradiated at 250 Gy. A dose of 300 Gy caused complete reproductive sterility in adults. These results suggest that the most susceptible stage was the egg stage, then nymph and adult stages. A dose of 300 Gy is suggested for quarantine treatment of commodities infested by L. paeta.     

Evaluation of the local population of Eretmocerus mundus (Hymenoptera: Aphelinidae) for biological control of Bemisia tabaci biotype B (Hemiptera: Aleyrodidae) in greenhouse peppers in Argentina

Bemisia tabaci biotype B is a key pest in pepper crops in Argentina. The parasitoid Eretmocerus mundus is frequently found parasitizing this whitefly in greenhouses without pesticide applications. The present studies were carried out with the objective of evaluating control obtained with different rate and number of parasitoid releases under experimental conditions. Release rate: cages with pepper pots were positioned in an experimental greenhouse and randomly assigned to the release rate treatments (0, 1 and 3 pairs of E. mundus/plant/week with a total of three introductions). Number of releases: similar cages were assigned to the number of parasitoid introduction treatments (0, 1, 2 and 3) with the best release rate obtained in the previous trial. In both assays whitefly (adults and nymphs) and parasitoid (parasitized nymphs) population sizes in each cage were monitored weekly for a period of 10 weeks. Results suggested that the introduction of 2 E. mundus/plant/week was enough to suppress host population compared to control treatment (peaks of 7.75 adults and 58.75 nymphs/cage and 643.75 adults and 1598 nymphs/cage, respectively) (p < 0.05), with 85% of parasitism. E. mundus had to be introduced three times to achieve the best pest control (peaks of 1.17 adults and 20.33 nymphs/cage vs. 55.67 adults and 75 nymphs/cage in control treatment) with 84% of parasitism (p < 0.05). These results were then validated in a pepper crop under experimental greenhouse conditions. Whitefly population was lower in those greenhouses where E. mundus was released compared to control greenhouses (0.15 adults and 0.71 nymphs/4 leaves and 0.73 adults and 1.64 nymphs/4 leaves, respectively), with a peak of 54% of parasitism (p < 0.05). We concluded that good suppression of B. tabaci could be achieved using E. mundus under spring conditions in Argentina.     

Density-mediated indirect effects of a common prey tadpole on interaction between two predatory bugs: <Emphasis Type="Italic">Kirkaldyia deyrolli</Emphasis> and <Emphasis Type="Italic">Laccotrephes japonensis</Emphasis>

This paper suggests that the nymphs of a specialist predator, Kirkaldyia (=Lethocerus) deyrolli (Belostomatidae: Heteroptera), are indirectly affected by their tadpoles’ prey. K. deyrolli nymphs and the predator Laccotrephes japonensis (Nepidae: Heteroptera) adults coexist in rice paddy fields. It was predicted that the difference in tadpole density may influence the K. deyrolli nymph survival rate. We first compared survival rates of the first instar nymphs of K. deyrolli in June (high tadpole density period) and July (low tadpole density period). Secondly, we investigated the survival rate of K. deyrolli nymphs at different tadpole densities and under the presence or absence of L. japonensis adults to examine whether higher tadpole density moderates predation pressure from L. japonensis adults to K. deyrolli nymphs, e.g., density-mediated indirect effects. As a result of the comparison, the survival rate of K. deyrolli nymphs in June was higher than that in July. For the field experiment, the slopes between the survival rate of K. deyrolli nymphs and tadpole density were positive under both predator presence and absence. However, the slope under the presence of a predator was steeper than that under absence of the predator (“predator-by-tadpole density interaction” was significant). These results suggest that a higher tadpole density in June provides an abundant food resource for K. deyrolli nymphs and also moderates predation pressure from L. japonensis.     

Microbial control of cotton pests: use of the naturally occurring entomopathogenic fungus Aspergillus sp. (BC 639) in the management of Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) and beneficial insects on transgenic cotton crops

The commercial adoption of transgenic Bacillus thuringiensis (Bt) cotton (Bollgard II®) reduced the use of insecticides to control Helicoverpa spp. However, the ineffectiveness of the Bt toxin against sucking pests such as silverleaf whiteflies (Bemisia tabaci) resulted in a marked increase in B. tabaci populations and in the use of insecticides to control this pest. The effect of the entomopathogenic fungus Aspergillus sp. BC 639 on B. tabaci and beneficial insects (predominantly predatory insects) was studied in commercial cotton field trials. The results showed that oil-based extracts of the entomopathogenic fungus BC 639 control the number of B. tabaci adults and nymphs in commercial transgenic cotton crops. The BC 639 fungus caused 60.0%, 67.2%, and 68.8% mortality in adults, and 54.6%, 62.3%, and 51.7% in nymphs at 7, 14, and 21 days after treatment, respectively, relative to the unsprayed controls. The effect of BC 639 at concentrations of 125, 250, and 500?ml/ha on low-density B. tabaci (～10 nymphs/leaf) did not differ significantly from that of the commercial insecticide (pyriproxifen). However, at higher densities (>50 nymphs per leaf), low concentrations of BC 639 (125 and 250?ml/ha) were not as effective as 500?ml/ha BC 639 in successfully controlling the pest. A simple graphic analysis suggested that the more B. tabaci nymphs per leaf, the fewer adults per leaf, and that once the number of nymphs increased to ～70 per leaf, a negative feedback regulatory effect reduced the survivorship of the nymphs and adults and/or caused the emigration of the adults from the contaminated leaves in search of new resources. Therefore, the ability of BC 639 to control B. tabaci adults and nymphs with minimal effects on predatory insects indicates its potential utility in supplementing integrated pest management programmes for cotton crops.     

Comparative studies of predation among feral,commercially-purchased,and laboratory-reared predators

The predatory activities of commercially-purchased adult Hippodamia convergens Guérin-Méneville and two laboratory-reared strains of adult Geocoris punctipes (Say) were compared with their feral counterparts. In single prey choice feeding tests, commercially-purchased and feral H. convergens were provided copious amounts of silverleaf whitefly, Bemisia argentifolii Bellows & Perring adults or eggs of pink bollworm, Pectinophora gossypiella (Saunders). Commercially-purchased H. convergens devoured more pink bollworm eggs and at a faster rate than the feral H. convergens. In contrast, feral H. convergens consumed more adult whiteflies and at a faster rate than commercial H. convergens. In multiple feeding choice tests, two distinctly different laboratory-reared strains and feral G. punctipes were provided a cotton leaf disk containing copious amounts of silverleaf whitefly eggs, nymphs, and adults. Virtually no predation was observed on whitefly eggs, but both laboratory strains of G. punctipes fed on more whitefly nymphs and adults than the feral G. punctipes. Moreover, both of the laboratory strains had a significantly faster feeding rate on adult whiteflies and spent significantly less time feeding on plant tissue than the feral strain. These results suggest that the augmentative biological control candidates retained their ability to prey on these selected prey items, even after being displaced from their overwintering site (H. convergens) or being reared in captivity (G. punctipes) for over 40 generations. Handling editor: Patrick De Clercq. This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or a recommendation for its use by the USDA.