The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), (Hemiptera: Cicadellidae), is a xylophagous leafhopper native to the southeastern United States and northern Mexico, with recent introductions into California, Arizona, French Polynesia, and Hawaii. It is a primary vector of the xylem-limited bacterium, Xylella fastidiosa Wells et al., the causative agent of Pierce’s disease of grape, citrus variegated chlorosis, phony peach, and numerous leaf scorch diseases. H. vitripennis uses several hundred species of host plants for feeding, development, and reproduction. Variation in host utilization allows H. vitripennis to respond to diurnal and seasonal changes in its nutrient-poor food source, xylem fluid, as well as changing nutritional requirements of each leafhopper developmental stage. Here we provide a conceptual model that integrates behavior, life history strategies, and their associated risks with the nutritional requirements of adult and nymphal stages of H. vitripennis. The model is a useful heuristic tool that explains patterns of host plant use, describes insect behavior and ecology, suggests new associations among the ecological components, and most importantly, identifies and supports the development of suppression strategies for X. fastidiosa aimed at reducing vector populations through habitat manipulation.

Supercooling points (SCPs) were measured for various life stages of male and female Lysiphlebus testaceipes (Cresson) parasitoids, along with mummies and its aphid host, Schizaphis graminum (Rondani). Some parasitoids were acclimated (4 h at 10°C before cooling down to the SCP) to determine whether this could significantly lower the SCP. Acclimation did not improve SCPs for L. testaceipes. An inverse relationship between age of the adult parasitoid and its SCP was detected. Nonacclimated male and female parasitoids older than 12 h after emergence spontaneously froze at the warmest mean temperatures (−20.32 ± 1.32 and −22.55 ± 0.62°C [SE], respectively). Younger female adult parasitoids (<6 h after emergence) and mummies had mean SCPs less than −26°C. The SCP for the greenbug host was slightly warmer at −25.98 ± 0.10°C. Knowledge of SCPs for L. testaceipes and its host S. graminum help provide insights about their ability to successfully function throughout the winter in the southern Great Plains.

Insects evolve levels of cold hardiness that are sufficient to meet the severity of thermal conditions in their hibernacula. This study examined freeze tolerance and related features in caterpillars of Hypercompe scribonia, which is the overwintering stage for this species, to compare with existing data for more northerly distributed species in Arctiidae that also overwinter as caterpillars. All specimens were collected from western Pennsylvania during mid-October 2004 and 2006 and eventually acclimated to 3°C for ≥4 wk. All caterpillars initially survived freezing at −3°C, which converted ≈45% of their body water into ice, and one third of them developed into moths. In contrast, freezing at −10°C was invariably lethal to caterpillars, even in the short term. Body composition (hemolymph osmolality, hemolymph glycerol, body mass, and water content) of caterpillars was stable between the 2 yr, with glycerol accounting for 3–5% of their solute. Thawed caterpillars showed an initial decline in routine aerobic metabolism that persisted through the first 6 h of the recovery period. H. scribonia caterpillars have a level of freeze tolerance that is adequate for hibernaculum conditions in western Pennsylvania; however, it is limited with respect to the tolerance levels of other arctiid caterpillars whose ranges extend northward well into colder regions of North America.

The level of an animal’s stress resistance is set by multiple intrinsic physiological and extrinsic environmental parameters. Body size is a critical intrinsic parameter that affects numerous fitness-related organismal traits including fecundity, survival, mating success, and stress resistance. The rate of cooling is a critical extrinsic environmental factor that can affect thermal stress resistance. Workers of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), display considerable variation in adult body size. Therefore, developing ecologically realistic models of thermotolerance in this species requires a consideration of body size. We tested the hypothesis that body size and cooling rate would interact to set the supercooling point in fire ant workers by exposing workers of a range of body sizes to three different cooling regimens: a very fast ramp of −10°C/min, an intermediate ramp of −1°C/min, and an ecologically relevant slow ramp of −0.1°C/min. Specifically, we asked whether large workers were more susceptible to differences in cooling rate than smaller workers. We found that body size had a considerable effect on supercooling point with the largest workers freezing at a temperature ∼3°C higher than the smallest workers. Cooling rate had a very small effect on supercooling point, and there was no interaction between the two factors. Therefore, the allometry of supercooling points across the range of worker body sizes does not change with cooling rate.

Gossypol is a constituent of the lysigenous foliar glands of cotton plants and is also found in glands in cottonseed. Gossypol exists as enantiomers because of restricted rotation around the binaphthyl bond. The biological activities of the enantiomers differ. For example, ( )-gossypol can be fed safely to nonruminants such as chickens, but (−)-gossypol cannot. Most commercial cottonseed contain a ( )- to (−)-gossypol ratio of ≈3:2. Conventional breeding techniques can be used to develop cottonseed that contains >95% ( )-gossypol. Notably, gossypol protects the plant from insect herbivores. Herein, we report the effect of various forms of gossypol on Heliothis virescens (Fabricius) larvae. Three levels (0.16, 0.24, and 0.32%) of racemic, ( )-, and (−)-gossypol were added to artificial rearing diets and were fed to H. virescens larvae. All 0.24 and 0.32% gossypol diets significantly lengthened days-to-pupation and decreased pupal weight compared with the control. Percent survival was significantly less for larvae reared on diets containing 0.24% of all three forms of gossypol as compared with the control diet. ( )-Gossypol was superior or equivalent to racemic gossypol as measured by the three parameters studied. Higher concentrations of all gossypol forms were required to reduce survival and pupal weights and increase days-to-pupation for larvae of H. virescens larvae compared with the concentration needed to affect larvae of Helicoverpa zea (Boddie), which was studied previously. These results indicate that current efforts to breed cotton lines containing mostly ( )-gossypol in seed should not significantly impair the plant’s natural defenses against insects.

Relatively little is known about the nutritional ecology of fruit flies in the genus Rhagoletis. In this study, nutrient amounts in male and female western cherry fruit fly, Rhagoletis indifferens Curran, and availability of nitrogen and sugar on surfaces of leaves, fruit, and extrafloral nectaries (EFNs) of sweet cherry trees, were determined from late May to late June 2005 and of sugar from EFNs from mid-May to late June 2007 in Washington state. Protein amounts in male and female flies did not differ over the season. Nitrogen was present on leaves, fruit, and EFNs during the sampling period, but amounts on leaves and fruit were lower in late May than the rest of the season. Sugar amounts in flies did not differ over the season. Sugar was present on leaf, fruit, and EFN surfaces all season, but amounts on all three were lower in late May than later in the season. Fructose and glucose were the predominant sugars on all plant surfaces, but sucrose was also present in nectar from EFNs. In outdoor and field cage experiments in 2004 and 2006, more flies survived when cherry branches with leaves and fruit were present than absent. Results suggest that R. indifferens maintains stable protein and sugar levels throughout the season because sufficient amounts of nutrients are found in cherry trees during this time and that increases in nutrient availability caused by ripening and damaged cherries later in the season do not result in increased amounts of nutrients in flies.

We test for fitness costs of resistance in a natural host–parasite system, involving Drosophila nigrospiracula and ectoparasitic mites, Macrocheles subbadius. We contrasted rates of mortality at embryonic and pupal stages of host ontogeny between replicate-resistant and -susceptible (control) lines at different temperatures (24, 28, and 34°C). Evidence for a cost of resistance was shown as a 17% overall reduction in egg hatch rate in replicate-resistant lines, although this effect was heterogeneous across replicate selection experiments. This cost of resistance was not magnified under thermal stress. Pupa survivorship was statistically invariant between resistant and control lines, at either temperature. Embryo and pupa mortalities were significantly elevated at the high temperature, confirming that the thermal treatment was physiologically stressful. The results suggest differential sensitivity of life history traits to the pleiotropic effects of genetic resistance against ectoparasitic mites.

Liposcelis badia Wang, Wang, and Lienhard was firstly recorded as a novel species of Liposcelididae in 2006 in China. In this study, the development, survival, and reproduction of L. badia were evaluated at eight constant temperatures (between 20 and 37.5°C). The population reared at 37.5°C failed to develop or reproduce. Between 20 and 35°C, the developmental period from egg to adult varied from 46.5 d at 20°C to 17.2 d at 32.5°C. The lower temperature developmental thresholds from egg, first through third stadia, and combined immature stages were estimated at 15.0, 14.5, 9.1, 8.0, and 10.0°C; and the upper temperature thresholds were 39.5, 40.0, 38.9, 39.6, and 40.0°C, respectively. The survival rate from egg to adult was 48.2% at 27.5°C and 19.8 and 18.0% at 20 and 35°C, respectively. After emergence, the adult had a short preoviposition period that ranged from 6.4 d at 20°C to 3.8 d at 30 and 32.5°C. L. badia produced the most eggs at 20°C and the fewest at 35°C. The population reared at 27.5°C had the highest intrinsic rate of increase, net reproductive rate, the shortest populations doubling time, and shorter mean generation time compared with the other temperatures. It is suggested that the optimal range of temperature for L. badia population growth is 27.5–30°C.

Tannins are believed to function as plant defenses against caterpillars, in part, as a result of their oxidation in the midgut lumen. One putative mode of action that has not been examined in leaf-feeding larvae is oxidative stress in midgut tissues that results from tannin oxidation in the midgut lumen. The test species used in this study, Malacosoma disstria Hübner (Lasiocampidae), is known to have higher levels of phenolic oxidation in its midgut contents when it consumes the oxidatively active leaves of sugar maple (Acer saccharum Marshall) than when it consumes the leaves of red oak (Quercus rubra L.). This study tested the hypothesis that increased phenolic oxidation in the midgut lumen of M. disstria is associated with increased oxidative stress in its midgut tissues. Three markers (oxidized ascorbate:total ascorbate, oxidized glutathione:total glutathione, and oxidized proteins) were measured in larvae fed either sugar maple or red oak leaves. In addition, we examined whether superoxide dismutase (SOD) activity might be a useful inducible marker of oxidative stress in M. disstria midgut tissues. Three of the markers indicated that significantly higher levels of oxidative stress were produced in the midgut tissues of M. disstria that fed on sugar maple than on red oak. However, SOD activity did not differ between sugar maple– and red oak–feeding larvae. This study is the first to show a link between phenolic oxidation in the midgut contents of caterpillars and oxidative stress in their midgut tissues.

A current trapping system for Anastrepha fruit flies uses a two-component food-based synthetic attractant consisting of ammonium acetate and putrescine (1,4-diaminobutane). Development of more effective monitoring programs may be realized through identification of additional attractant chemicals. This study examined response of the Caribbean fruit fly, Anastrepha suspensa (Loew), to putrescine and four homologous terminal diamines, differing only in carbon chain length. Using a fixed dose of each diamine substrate, electroantennogram (EAG) responses from mature females to putrescine and cadaverine (1,5-diaminopentane) were not significantly different from each other but were significantly greater than responses to longer chain diamines. Over a range of doses tested, mean female EAG response was greater than male response to both putrescine and cadaverine. In an initial field test, capture of female flies in traps baited with ammonium acetate and either putrescine or cadaverine was higher than in traps baited with ammonium acetate and any of the other diamines. In a subsequent field test, traps baited with putrescine, cadaverine, or 1,6-diaminohexane in combination with ammonium acetate captured more female flies than traps baited with ammonium acetate alone. A significantly greater synergistic effect on female captures was observed with either putrescine or cadaverine than with 1,6-diaminohexane. Thus, of the diamines evaluated, cadaverine elicited both antennal and behavioral responses comparable to that of putrescine and will be studied further as a potential attractant for pest Anastrepha species.

Wax-based pelleted sex pheromone formulations were tested for efficacy in managing oriental beetle, Anomala orientalis Waterhouse, in turfgrass. Four pellet formulations were field tested at 25 g pheromone/ha during 2006 and 2007. Application patterns included pellets specifically placed in a uniform grid pattern and pellets scattered by a broadcast spreader. Treatment efficacy was measured by monitoring male A. orientalis captures in pheromone-baited traps, determining mating success of confined virgin females, and estimating subsequent densities of A. orientalis larvae in soil/sod samples. All formulation and application pattern combinations effectively suppressed mating for 2 wk after application as measured by reduction in male trap captures and mating success of confined virgins. Two formulations gradually lost efficacy beginning 2 wk after application and the two others after 3–4 wk. Application pattern had no effect on trap captures. The most effective formulation reduced trap captures by ≥90% for 36 d, reduced mating success of confined females by 86–100% until 24 d after treatment, and reduced A. orientalis larval populations by 69%. In a previous study, sprayable formulations resulted in nuisance contamination of shoes that attracted male beetles outside of pheromone-treated areas. In contrast, shoes walked through pellet-treated areas did not attract male beetles. Pellet formulations have great potential for A. orientalis mating disruption, but more research is needed to optimize performance.

Studies were conducted to examine the deposition of microcapsules and the attractiveness of treated apple leaves, Malus domestica Borkhausen, for codling moth, Cydia pomonella L., after low-volume concentrated sprays [24.7 g (AI) in 12 liters of water/ha] of a microencapsulated (MEC) sex pheromone formulation (CheckMate CM-F). Nearly 30% of leaves collected from sprayed zones within tree canopies had no microcapsules, whereas 20% had >20 microcapsules. Microcapsule density was correlated with leaf area, and significant differences in the density of microcapsules per leaf were found because of both height and depth in the canopy relative to the sprayed zone and leaf surface. In general, the highest concentration of microcapsules was deposited on the underside of leaves in the sprayed zone. However, deposition was greater on the upper than the bottom surface of leaves in the canopy below the spray zone and in the tops of trees on the opposite side of the canopy. Field-aged MEC-treated apple leaves elicited upwind flight and moth contact in flight tunnel tests for at least 5 wk. Precipitation reduced the attractiveness of leaves, particularly for leaves treated only on their upper versus bottom surface. Traps in unsprayed orchards baited with MEC-treated artificial leaves were attractive for 5 wk. Moth catches in similar traps placed in MEC-sprayed plots were low but increased significantly over 3–4 wk. These data suggest that, after a brief initial period of sensory disruption, low-volume MEC sprays create point sources of sex pheromone (leaves) within the orchard that may enhance mating disruption through competitive attraction.

Many capture–recapture studies on adult dragonflies have found male-biased sex ratios. However, few have estimated survivorship of males and females separately from data on frequency of recaptures in the field. Even when daily survival and capture probabilities are estimated separately, controversies can arise on whether sex biases in local survival are to be attributed to mortality or permanent emigration from the study site. The knowledge of male and female movements, assessed on an appropriate scale (i.e., within and outside the breeding site), can help address this issue. In this paper, we performed a 4-yr capture–recapture study of two Libellula fulva Müller populations in northwest Italy. Cormack-Jolly-Seber models were used to get unbiased estimates of demographic parameters (daily survival and capture probabilities, sex ratio, mean life span, and population size). Movement parameters were measured directly by georeferencing encounters. Moderate differences in survival, with males surviving better than females, were found in one population and not in the other, suggesting that these differences are not an inherent characteristic of the species. In the population with lower female survival, females were not more vagile than males, thus indicating their lower survival was caused by actual mortality rather than to emigration. In the population with no survival differences between males and females, marked males outnumbered females, but estimated sex ratios were ≈1:1 or female biased. Therefore, raw field data were misleading because they led to underestimates of the more elusive sex and overestimates of the more detectable one (males). Survival and movement differences detected in the two populations are discussed in the framework of local environmental and demographic factors.

The apple maggot, Rhagoletis pomonella (Walsh), is an important pest of apples in the Southern Appalachian Mountains. The seasonal phenology of adult flight activity was monitored with baited red sphere traps in eight abandoned apple orchards in the Southern Appalachian Mountains of North Carolina and South Carolina in 2004 and 2005, ranging in elevation from 300 to 853 m. Trap captures showed that at elevations of ≥630 m, the apple maggot was primarly univoltine, with adult activity most intense during a 2-mo period from late June to late August in 2004 and from mid-July to mid-September in 2005. At lower elevation sites in North Carolina and South Carolina (300–328 m elevation), adults were active for a 5- to 6-mo period from late May or early June into November. Trap captures suggested the apple maggot was bivoltine at lower elevation sites. There was also evidence from trap captures of distinct early and late emerging flies from overwintering pupae. A winter simulation study in which pupae from maggot-infested apples collected in July (early emergers) and September (late emergers) were exposed to cold treatments (4°C) ranging from 3 to 52 wk showed that the postdiapause rate was more rapid for early versus late emergers when exposed to a minimum 8-wk cold period. For pupae receiving cold treatments ranging from 8 to 19 wk, early emergers eclosed 257–321 DD before late emergers, but this difference was only 146 DD for pupae receiving a 35-wk cold treatment. Climatic conditions in the Southern Appalachian Mountains, including a relatively long growing season and mild winters, are conducive to a more protracted apple maggot emergence period compared with more northern locations.

Larval sex dimorphism, fecundity, and sex ratios have been rarely studied in lotic insects, but can have ecological, energetic, and evolutionary importance. I evaluated the effect of microhabitat quality on larval and pupal sex dimorphism and sex ratios using a Hawaiian chironomid (Telmatogeton torrenticola Terry) and examined differences between sex-corrected and noncorrected biomass and secondary production estimates. Larvae and pupae were collected from two microhabitat types defined by microscale flow hydraulics to test for habitat effects on sex dimorphism, sex ratios, fecundity, standing stock biomass, secondary production, and Production/Biomass (P/B) ratios. Female larvae were more than twice as large as males, and this was more pronounced in pupae. Males were twice as abundant as females, and there was no effect of habitat on fourth-instar density. There was, however, a significant habitat effect on morphology, larval body size, standing stock biomass, secondary production, and P/B ratios. Biomass was not statistically different between sexes, but sex-corrected biomass was significantly lower than noncorrected biomass in both habitats but is likely not biologically significant. Sex-corrected secondary production estimates were 69–85% of noncorrected estimates depending on habitat, and sex correction did have a significant effect on P/B ratios in microhabitats of lower quality. This study is one of the first to address sex dimorphism and sex ratios in estimates of standing stock biomass and secondary production, providing initial evidence that microhabitat quality is important to understanding chironomid population biology and the potential role of sex-related demographics in estimates of productivity.

A major challenge to addressing biological invasions is that the need for emergency responses often precludes opportunities to analyze the dynamics between initial establishment and population eruption. Thus, a broader understanding of underlying processes and management opportunities is often lacking. We examined the effects of habitat structure and natural enemies on recently established preeruptive gypsy moth, Lymantria dispar L., populations over 4 yr in northeastern Wisconsin. Forty-five sites were established across a range of habitat structures in oak-dominated northern hardwood forests. The number of egg masses was positively related to percent composition of oaks and other favored species. Other life stages were not related to habitat structure variables. Abundance of each life stage can predict the subsequent life stage with variable degrees of accuracy, but male moth densities were only a weak predictor of egg mass or larval densities the following year. The parasitic fly Compsilura concinnata (Meigen), an introduced generalist with deleterious nontarget effects, caused the highest mortality to larvae. The specialist pathogens Entomophaga maimaiga and nucleopolyhedrosis virus were widely distributed but caused less mortality than reported in the northeastern United States, where gypsy moth has been established much longer. Small mammals are the major predators of pupae as elsewhere, but invertebrates seem less important along the western than southern advancing front of gypsy moth. Overall habitat structure did not influence natural enemy populations. These results suggest that the pre-eruptive phase is distinct from the pre-establishment phase by high mating success and from the eruptive phase by the prominent role of generalist natural enemies. Improved understanding of these dynamics can help guide silvicultural and biocontrol strategies in newly invaded regions of the Midwest and provide general insight into invasive forest defoliators.

We studied the life history, geographic distribution, behavior, and ecology of Larinus filiformis Petri (Coleoptera: Curculionidae) in its native range to determine whether it is worthy of further evaluation as a classical biological control agent of yellow starthistle, Centaurea solstitialis (Asteraceae: Cardueae). Larinus filiformis occurs in Armenia, Azerbaijan, Turkey, and Bulgaria and has been reared only from C. solstitialis. At field sites in central and eastern Turkey, adults were well synchronized with the plant, being active from mid-May to late July and ovipositing in capitula (flowerheads) of C. solstitialis from mid-June to mid-July. Larvae destroy all the seeds in a capitulum. The insect is univoltine in Turkey, and adults hibernate from mid-September to mid-May. In the spring, before adults begin ovipositing, they feed on the immature flower buds of C. solstitialis, causing them to die. The weevil destroyed 25–75% of capitula at natural field sites, depending on the sample date. Preliminary host specificity experiments on adult feeding indicate that the weevil seems to be restricted to a relatively small number of plants within the Cardueae. Approximately 57% of larvae or pupae collected late in the summer were parasitized by hymenopterans [Bracon urinator, B. tshitsherini (Braconidae) and Exeristes roborator (Ichneumonidae), Aprostocetus sp. (Eulophidae), and unidentified species of Eurytomidae and Ormyridae]. This weevil may be a better choice than the other capitula insects already established in the United States, particularly in colder parts of the plant’s range.

Homalodisca vitripennis, the glassy-winged sharpshooter, poses a serious threat to grape production because of its ability to vector Xylella fastidiosa, the causal agent of Pierce’s disease. The glassy-winged sharpshooter is native to the southeastern United States, and over the last 20 yr has expanded its range into Texas and California and more distantly into French Polynesia. A better understanding of the reproductive dynamics of H. vitripennis will aid in assessment of the invasiveness of this insect and may aid in refinement of control strategies. First, females of known age were dissected to determine egg maturation schedules. Females did not produce mature eggs until at least 1 wk after adult emergence. Oviposition reduced the number of mature eggs carried by females, suggesting a continuous cycle of egg deposition followed by egg maturation where females may experience transient egg limitation. Second, males and females were monitored over their entire lifetimes to determine longevity and fecundity. Males and females were long lived with an average lifespan of 4 mo. Females displayed one of three temporal patterns of oviposition: (1) no oviposition, (2) oviposition began <40 d after emergence, or (3) oviposition began >40 d after emergence. In general, oviposition was independent of female age. Finally, egg maturation rates of field-collected females were determined. Egg maturation rates varied with time of year and maximum egg maturation rates coincided with periods when oviposition was expected to be high. The highest egg maturation rate observed was five eggs per female per day.

Reproductive compatibility of interstrain matings in plum curculio, Conotrachelus nenuphar (Herbst), was studied during the summers of 2004 and 2006. There was a unidirectional incompatibility in the cross-matings along a rough north to south transect of the range of plum curculio (4 × 4 two-factorial design). There was significantly lower fertility in West Virginia males mated with New York and Virginia females (40 and 29%, respectively), and Florida males had a significantly lower fertility with Virginia and West Virginia females (46 and 37%, respectively), but Florida females were compatible with males of all four populations. Three northern populations were compatible with each other in all cross-mating combinations (New York, Massachusetts, and New Jersey; 3 × 3 two-factorial design). There was a unidirectional reproductive incompatibility in the combination of New Jersey males with Florida females (47%) and a bi-directional incompatibility between Florida and West Virginia reciprocal cross-mating (26 and 21%, respectively). The pattern of the reproductive incompatibility among geographic populations could help us to distinguish plum curculio strains and to clarify their strain distribution range to enrich our knowledge on their population ecology and biosystematics.

Carabids were sampled in 2000 (pretreatment year) and 2003–2005 in experimental plots in southern Alberta, Canada, after a rotation of beans, wheat, and potato under sustainable and conventional farming practices. Each phase of the rotation was present in every year. Crop type had a stronger effect than sustainable treatment on carabid-expected species richness, diversity, and species composition. However, carabid activity density was consistently higher in plots under sustainable treatments than those maintained conventionally. Potato plots, which were sprayed with insecticide for pest control, showed a significantly lower carabid activity density than the other crops. These results support other studies showing the beneficial effect of sustainable farming on activity density of carabid beetles.

The response of forest insect communities to disturbances such as timber harvest will likely depend on the underlying spatial structure of species assemblages before the disturbance occurs. Unfortunately, many studies of forest management implicitly assume homogeneity of community structure before harvest; postlogging communities are inferred to be a direct product of the imposed management. The goal of this study is to examine variation in the community structure of forest Lepidoptera using the pretimber harvest data on Lepidoptera from 20 forest sites within three watersheds at Morgan Monroe State Forest, IN. A total of 14,537 individuals representing 324 species of Lepidoptera were sampled from Morgan-Monroe State Forest in 2007. Sampling efficiency was not a function of management unit, and, surprisingly, we found little evidence that management units differed in overall community composition. Diversity partitioning suggested that >99% of Simpson diversity (species dominance) was determined at the local scale, and each site contained the same 10 dominant taxa in rank order. Variation in species richness seemed to be more a problem of sampling bias than underlying differences in habitat preference by moth feeding guilds. Finally, Mantel tests suggested that forest moth communities at Morgan-Monroe are not spatially autocorrelated. The results here are encouraging because they strongly suggest that shifts in lepidopteran community structure should reflect the community response to disturbance rather than inherent spatial heterogeneity of species composition.

The parasitoid assemblage associated with a lepidopteran leafminer, Coptotriche japoniella (Tischeriidae), on an evergreen tree, Eurya japonica (Theaceae), was studied in the center of Japan to explore parasitoid coexistence mechanisms. The leafminer supported 12 parasitoid species. Eight abundant or common species were classified into five guilds according to their koinobiont/idiobiont mode and host-instar utilization pattern: early larval koinobiont, mid-larval idiobiont, mid-larval–late larval idiobiont, late larval–pupal idiobiont, and pupal idiobiont. The early larval koinobiont (Orgilus kumatai) and mid-larval idiobiont (Achrysocharoides sp.) seemed to be specialized on the host, whereas the members of the other guilds had a wide host range. The mid-larval–late larval (Cirrospilus diallus and Pnigalio sp.) or late larval–pupal idiobionts (Chrysocharis albipes, Apleurotropis kumatai, and Pleurotroppopsis japonica) facultatively hyperparasitized half of spinning larvae or pupae of the early larval koinobiont. These results suggest that parasitoid coexistence in this assemblage is greatly promoted by high levels of facultative hyperparasitism by idiobionts with wide host ranges on the dominant koinobiont.

To evaluate the potential of Podisus maculiventris (Say) (Heteroptera: Pentatomidae) as a biological control agent against viburnum leaf beetle, Pyrrhalta viburni (Paykull) (Coleoptera: Chrysomelidae), laboratory trials were conducted to measure prey consumption of P. maculiventris over nymphal development. Field trials tested the impact of augmentative releases of P. maculiventris nymphs on populations of P. viburni, using both open shrubs and caged branches of Viburnum trilobum. In the laboratory, P. maculiventris nymphs successfully developed while preying on P. viburni larvae and adults. Each nymph consumed an average of 100.6 larvae or 16.9 adults. Immature development duration was comparable between nymphs feeding on P. viburni adults and those given Galleria mellonella (L.) (Lepidoptera: Pyralidae) larvae as prey. In field trials, inundative releases of 30 P. maculiventris nymphs on naturally infested V. trilobum shrubs significantly reduced pest defoliation on shrubs infested with <3,000 larvae but had no effect on shrubs with heavier infestations. On caged branches, individual nymphs successfully developed when feeding only on P. viburni larvae. These results show that P. viburni larvae and adults are suitable prey for P. maculiventris and this predator could potentially be developed as a biological control agent against P. viburni.

Chrysoperla externa (Hagen) is a generalist predator in agroecosystems. We assessed the effect of cypermethrin, endosulfan, methoxyfenozide, and spinosad on immature development time, survivorship, sex ratio, fecundity, and fertility on this organism in laboratory toxicity tests. Effects on second-generation organisms were also studied. Exposures were realized by dipping ≤24-h-old eggs in pesticide solutions at maximum field recommended concentrations (MFRCs) registered in Argentina. Although no significant ovicidal effect was detected with any of the compounds, endosulfan and cypermethrin produced 96 and 100% mortality, respectively, on larvae 48 h after hatching. Spinosad caused significantly higher mortality than controls but this effect was less immediate, lasted longer and was less intense than effects with conventional insecticides. Methoxifenozide did not produce significant mortality in any stages. Spinosad and cypermethrin reduced egg development time, but no similar effects were observed with other insecticides. Methoxyfenozide inhibited the fecundity during the first 24 h; however, fertility was not affected. Spinosad had no effect on fecundity or fertility of the adults. No long-term detrimental effects on the progeny were detected for spinosad and methoxyfenozide. Conventional insecticides (endosulfan and cypermethrin) were more toxic than biorationals ones when applied to eggs of C. externa. The ecotoxicological studies showed the neonate-L₁ larvae as a susceptible developmental stage. These data indicate that the biorational insecticides tested are compatible with conserving C. externa.

Ant attendance is known to affect the population dynamics of aphids and may increase or decrease aphid populations through stimulation, predation, or protection. In this study, we performed a series of laboratory experiments to examine the effects of ant attendance on populations of the soybean aphid Aphis glycines. Aphid colonies were exposed to the predators Harmonia axyridis (Coccinellidae) and Orius insidiosus (Anthocoridae) and a parasitoid Aphidius colemani (Aphidiidae) in the presence and absence of attending Monomorium minimum (Formicidae). We also tested for direct effects of ant attendance in the absence of natural enemies. Ants attending soybean aphid populations were observed harassing or killing O. insidiosus and H. axyridis. Attendance interfered with both predator species, resulting in reduced predation and an increase in aphid numbers up to 10-fold in the presence of ants. Ants were not observed directly interfering with the parasitoid A. colemani, but the number of parasitized aphids was higher in aphid colonies that were left unattended by ants.

To survey fungal pathogens and parasitoids of aphids in the low-latitude plateau of Yunnan, southwest China, 3,553 migratory alates of Brevicoryne brassicae, Lipaphis erysimi, and Myzus persicae were attracted to a yellow-plus-plant trap from air during a full-year period and individually reared on cabbage leaves for 7–14 d at 18–22°C and L:D 12:12. Among the trapped alates, 19.2% were killed by 10 species of aphid-pathogenic fungi after survival of 2.3 d (range, 1–7 d). Another 2.8% were mummified by the wasps Aphidius gifuensis, Diaeretella rapae, Ephedrus plagiator, and Aphelinus mali after survival of 4.9 d (range, 1–11 d). Most of the mycosed alates (77.8%) died from Entomophthorales predominated by Pandora neoaphidis (42.7%) and Zoophthora radicans (14.5%), followed by P. nouryi, Neozygites fresenii, Conidiobiolus spp., Entomophthora planchoniana, and Z. aphidis in decreasing frequencies. A mitosporic fungus, Lecanicillium lecanii, was found frequently in L. erysimi alates trapped in rainy season. However, B. brassicae alates captured in dry season were infected or parasitized very occasionally. The predeath fecundity of the infected or parasitized alates warranted successful colonization on plants, although greatly reduced, and was well shown by the fitted probability for a given fecundity per capita and the increasing mean size of their progeny colonies. Contagious transmission of the alate-borne mycosis in most of the colonies caused high progeny mortalities within 14 d. The results highlight for the first time the diversity of aphid pathogens and the spread of both pathogens and parasitoids with host dispersal flight in the low-latitude plateau.

Plum curculio, Conotrachelus nenuphar, is a major pest of pome and stone fruits in North America. We evaluated the potential efficacy of two entomopathogenic nematode species for suppression of plum curculio in northern regions, targeting life stages that reside in soil during spring and summer. A strain of Heterorhabditis bacteriophora isolated from soil infested with plum curculio in northern Utah and a commercially available strain of Steinernema feltiae known to tolerate cool temperatures were tested in the laboratory against three life stages of plum curculio. Bioassays used the southern strain of plum curculio because availability of the northern strain from the field was inadequate. H. bacteriophora was more virulent than S. feltiae to all plum curculio life stages. Adults and pupae were more susceptible than larvae. Temperature bioassays were conducted with a surrogate host: last instars of Galleria mellonella. The two nematodes exhibited different, but overlapping, thermal activity ranges. Both species performed best at 20°C: virulence and reproductive potential was higher; however, H. bacteriophora was superior to S. feltiae at 30°C and vice versa at 10°C. The reproductive potential of H. bacteriophora was >2.5 times greater than for S. feltiae, and H. bacteriophora required fewer individuals to initiate a successful host infection. S. feltiae was a better fit for temperatures expected in northern climates, but H. bacteriophora was more virulent to plum curculio and produced more infective juveniles that may benefit nematode recycling and continuation and spread of insect suppression in the field.

European corn borer, Ostrinia nubilalis, flight behavior was examined in laboratory experiments. Adults were each tethered to 1 of 16 round-about flight mills in an environmental chamber, and the data were relayed to a computer. Parameters analyzed included duration, distance, and speed of the longest continuous flight and total flight time during an 8-h night. Comparisons were made between unmated and mated adults of both sexes at different ages up to 5 d after emergence. For unmated females, duration of the longest flight was highest the first night after emergence, declining significantly by 5 d of age. In contrast, duration of the longest flight for males was lowest at 1 d of age, increasing significantly by 3 d of age. Flight speed of females was roughly twice that of males at all ages. Mating did not affect flight behavior of either sex at any age tested, but mated adults could not be tested before 2 d of age because the first night was needed for mating. The pattern of age-specific flight behavior suggests that unmated females engage in obligate migratory flight the first full night after emergence. The median duration of this flight was ≈2 h in our experiments, with some adults flying continuously for the full 8 h of darkness. Females of other ages and males of all ages tested were capable of long-duration flights, but they more likely represent foraging flight. These results help explain the high dispersal rate of newly emerged adults from release sites in field experiments.

Environmental conditions during egg and larval development may influence the dispersal ability of insect pests, thus requiring seasonal adjustment of control strategies. We studied the longest single flight, total distance flown, and the number of flights initiated by wild Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) to determine whether the flight performance of overwintered cactus moths with a prolonged feeding phase during development differs from nonoverwintered cactus moths. Pupae of field-collected and laboratory-reared moths were transported together from the United States to Switzerland, and flight mills were used to characterize the flight capacity of 24- to 48-h-old adults during their most active period of the diel cycle. The lack of seasonal variation in flight performance of those moths that developed under controlled environment but were fed with field-collected Opuntia cacti showed that seasonal changes in host plant quality did not affect flight. This consistent flight performance in the mass-reared laboratory population throughout the year is beneficial for sterile insect technique programs, which aim to limit the dispersal of this pest. For field-collected C. cactorum, the larger overwintered females performed similarly to nonoverwintered females, indicating that longer feeding time at lower temperature increases body size but does not influence female flight capacity. Young mated females had a similar flight capacity to unmated ones, suggesting that gravid females may play an important role in invading new habitats. For males, overwintering increased the proportion of long-distance flyers, suggesting that they are well-adapted to locate the more sparsely dispersed females in the spring.

The effect of adult learning through an oviposition and host feeding experience was studied in two populations of Anisopteromalus calandrae (Hymenoptera: Pteromalidae), in choice and no-choice experiments in the laboratory using last instars of rice weevil, Sitophilus oryzae L., and lesser grain borer, Rhyzopertha dominica (F.), as hosts. In choice experiments, 20 wheat kernels infested by rice weevil and 20 by lesser grain borer were placed randomly in petri dish (15 by 100 mm) arenas. In no-choice experiments, 10 host-infested wheat kernels, either with rice weevils or with lesser grain borers, were mixed thoroughly in 500 g of uninfested wheat placed in a 0.945-liter glass jar (75 by 170 mm) arenas. A. calandrae females from a laboratory and field populations that were experienced with host larvae or naïve were introduced singly into each experimental arena and allowed to sting and oviposit for 24 h. An oviposition experience with rice weevil or lesser grain borer had a stronger effect on host preference in choice experiments compared with experiments with naïve wasps. Host-finding and parasitism rates were increased by prior experience with rice weevils in no-choice experiments. A. calandrae females clearly preferred rice weevil larvae for parasitization over larvae of lesser grain borer regardless of parasitoid population or prior experience. Also, A. calandrae females chose rice weevil larvae for producing female progeny and lesser grain borer for male progeny in choice experiments. The implications of the results of this study are discussed in relation to host preference and the selection of parasitoid populations for biological control programs in stored grains.

We evaluated the potential for competition between the exotic ichneumonid parasitoid Pimpla disparis Vierick and the native ichneumonid Itoplectis conquisitor Say, in the form of multiparasitism and destructive host feeding, by examining how previous oviposition experience influenced host selection. Both species commonly attack the host species, bagworm, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae), in central Illinois. We used in our study adult female parasitoids that were naïve, had previously oviposited into hosts that contained heterospecifics, or had oviposited into hosts that initially were unparasitized. Naïve parasitoids of both species were disinclined to oviposit into hosts that already were parasitized by heterospecific larvae, suggesting that female parasitoids could detect the larvae. However, parasitoids with prior oviposition experience were less selective and oviposited into hosts that already were parasitized and unparasitized hosts. Female P. disparis and I. conquisitor probed parasitized hosts more frequently than unparasitized hosts. Adult female parasitoids of both species rarely directly fed on hosts, but those that did preferred to feed on hosts that already were parasitized. For both parasitoid species, the first larva to colonize a multiparasitized host was the most likely to survive to adulthood.

Species richness is the most widely used measure of biodiversity, but the relationship between the observed and true numbers of species present in a study site is not always investigated. A field study at 27 habitat remnants was used to measure the effectiveness of a survey regimen for assessing species richness of butterflies and day-active moths in southwest Western Australia. Observed species richness was compared with known species richness and to statistical estimates of true species richness, and the bootstrap was found to be the best predictor of true richness. A regimen of 10-m-wide walk transects sampled on six occasions at 2-wk intervals during the austral spring (mid-September to mid-December) gave an almost complete inventory of resident species for each site (≈87% of the fauna detected), consistent with two previous studies that have assessed sample completeness in temperate areas. The abundance of diurnal lepidoptera showed large temporal variation over the flight season and varied to a lesser extent with time of day and temperature, but not with cloud cover or wind speed. Transect route and sampling frequency were the most important considerations in devising a survey regimen: transects placed off tracks detected both more species and more individuals per unit length. The fraction of the site area sampled was relatively unimportant, and even low sampling fractions of 1–2% may be adequate if the number and frequency of surveys is sufficient. The design of future surveys would be facilitated if sampling fraction was routinely reported and examined in relation to sample completeness.

The interactions of Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) with their hosts (Passifloraceae) in southern Brazil are poorly understood. Previous studies have indicated that both species use several host species and plant parts and have superior performance on wild hosts. This study evaluated feeding preferences and host plant use under both laboratory and field conditions. Choice tests were performed to determine preference for Passiflora suberosa parts, preference for P. suberosa and Passiflora misera immature and ripe fruits, and preference for P. suberosa, P. misera, and Passiflora edulis shoots. A field survey was carried out to assess H. clavigera and A. foliacea marginella use of P. suberosa parts. In addition, immature and ripe fruits of P. suberosa and P. misera were characterized in relation to pH, phenols, and anthocyanins. First-instar nymphs preferred the terminal buds, shifting to immature fruits in the second instar. Both coreids more frequently fed on immature fruits than on ripe ones. Neither species showed a significant preference among host species. The immature fruits presented higher phenol content as compared with the ripe fruits; the opposite was observed for anthocyanins. In the field, immature fruits and mature leaves were selected for feeding and resting. Thus, this study confirms the food mixing condition of these coreids, as well as the importance of fruits for their nutrition. Phenols, and presumably water, in the fruits may play a role in their feeding choices.

Insect herbivory has variable consequences on plant physiology, growth, and reproduction. In some plants, herbivory reduces photosynthetic rate (Pn) activity on remaining tissue of injured leaves. We sought to better understand the influence of leaf injury on Pn of common milkweed, Asclepias syriaca (Asclepiadaceae), leaves. Initially, we tested whether Pn reductions occurred after insect herbivory or mechanical injury. We also (1) examined the duration of photosynthetic recovery, (2) compared mechanical injury with insect herbivory, (3) studied the relationship between leaf Pn with leaf injury intensity, and (4) considered uninjured leaf compensatory Pn responses neighboring an injured leaf. Leaf Pn was significantly reduced on mechanically injured or insect-fed leaves in all reported experiments except one, so some factor(s) (cardiac glycoside induction, reproductive investment, and water stress) likely interacts with leaf injury to influence whether Pn impairment occurs. Milkweed tussock moth larval herbivory, Euchaetes egle L. (Arctiidae), impaired leaf Pn more severely than mechanical injury in one experiment. Duration of Pn impairment lasted >5 d to indicate high leaf Pn sensitivity to injury, but Pn recovery occurred within 13 d in one experiment. The degree of Pn reduction was more severe from E. egle herbivory than similar levels of mechanical tissue removal. Negative linear relationships characterized leaf Pn with percentage tissue loss from single E. egle–fed leaves and mechanically injured leaves and suggested that the signal to trigger leaf Pn impairment on remaining tissue of an injured leaf was amplified by additional tissue loss. Finally, neighboring uninjured leaves to an E. egle–fed leaf had a small (≈10%) degree of compensatory Pn to partly offset tissue loss and injured leaf Pn impairment.

We characterized gut microbial communities in the emerald ash borer, Agrilus planipennis Fairmaire, an invasive phloem-feeding and wood-boring beetle that has caused extensive mortality to urban and forest ash trees. Analyses included both 16S rRNA gene–based and culture-based approaches. We estimated that the emerald ash borer gut harbors 44, 71, and 49 operational taxonomic units (OTUs_0.03) in the larval, prepupal, and adult stages, respectively, and a total of 132 OTUs_0.03 when data from the three stages are pooled. The larval gut community shared all its OTUs_0.03 with either the adult or the prepupal gut community, and the adult and prepupal gut communities shared 27 OTUs_0.03. Twenty-two OTUs_0.03 were shared among the three life stages. Rarefaction analyses suggest that these gut microbial communities are close to being completely sampled at the phylum level. Culture-independent techniques yielded a higher diversity of bacteria than did culturing. Three species of bacteria inhabiting guts of emerald ash borer showed cellulolytic activity. The diverse, dynamic, and presumably multifunctional microbial community associated with emerald ash borer guts suggests that invasive insects should be viewed as multispecies complexes and that such an interpretation can improve our ability to develop more effective management approaches.

The Mediterranean corn borer, Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae), is a major pest of maize in the Mediterranean area. Transgenic Bt maize expressing the Cry1Ab toxin from the bacterium Bacillus thuringiensis can effectively control this pest. The characterization of S. nonagrioides population structure, at a large geographical scale, would provide some insight in decision making for resistance management. The genetic relationships among nine populations from Spain, one from France, one from Italy, three from Greece, and one from Turkey were assessed using Random Amplyfied Polymorphic DNA (RAPD) markers. Populations from France and Spain formed a cluster independent from a cluster of populations collected in Italy, Turkey, and Greece in a unweighted pair-group method with arithmetic average dendrogram constructed from Nei’s genetic distances. Average genetic differentiation among samples was significant for all geographical groupings analyzed (F_ST = 0.160 ± 0.014 for Spanish populations; 0.133 ± 0.022 for Spanish and French populations; and 0.095 ± 0.010 for Greek, Italian, and Turkish populations). Genetic differentiation was also significant for all paired comparisons of populations, including two Spanish populations separated by only 15 km with no apparent geographical barriers. No pattern of isolation by distance was observed among Mediterranean corn borer populations collected in Spain and France. These results suggest a limited genetic exchange between relatively distant S. nonagrioides populations in Europe, which might contribute to decreased rate of spread of resistance alleles once resistance has developed at a certain site.

Genetically modified insect-resistant rice lines containing the cry1Ac gene from Bacillus thuringiensis (Bt) or the CpTI (cowpea trypsin inhibitor) gene developed for the management of lepidopterous pests are highly resistant to the major target pests, Chilo suppressalis (Walker), Cnaphalocrocis medinalis (Guenée), and Scirpophaga incertulas (Walker), in the main rice-growing areas of China. However, the effects of these transgenic lines on Sesamia inferens (Walker), an important lepidopterous rice pest, are currently unknown. Because different insect species have varying susceptibility to Bt insecticidal proteins that may affect population dynamics, research into the effects of these transgenic rice lines on the population dynamics of S. inferens was conducted in Fuzhou, southern China, in 2005 and 2006. The results of laboratory, field cage, and field plot experiments show that S. inferens has comparatively high susceptibility to the transgenic line during the early growing season, with significant differences observed in larval density and infestation levels between transgenic and control lines. Because of a decrease in Cry1Ac levels in the plant as it ages, the transgenic line provided only a low potential for population suppression late in the growing season. There is a correlation between the changing expression of Cry1Ac and the impact of transgenic rice on the population dynamics of S. inferens during the season. These results indicate that S. inferens may become a major pest in fields of prospective commercially released transgenic rice, and more attention should be paid to developing an effective alternative management strategy.