Although corn (Zea mays L.) and soybeans (Glycine max L.) do not require pollination, they offer floral resources used by insect pollinators. We asked if a similar community of insect pollinators visits these crops in central Iowa, a landscape dominated by corn and soybean production. We used modified pan traps (i.e., bee bowls) in both corn and soybean fields during anthesis and used nonmetric multidimensional scaling (NMS) to compare the communities found in the two crops. Summed across both crops, 6,704 individual insects were captured representing at least 60 species, morphospecies, or higher-level taxa. Thirty-four species were collected in both crops, 19 collected only in corn and seven were collected only in soybean. The most abundant taxa were Lasioglossum [Dialictus] spp., Agapostemon virescens Cresson, Melissodes bimaculata (Lepeletier), and Toxomerus marginatus (Say), which accounted for 65% of the insect pollinators collected from both crops. Although social bees (Apis mellifera L. and Bombus spp.) were found in both crops, they accounted for only 0.5% of all insects captured. The NMS analysis revealed a shared community of pollinators composed of mostly solitary, ground nesting bees. Many of these species have been found in other crop fields throughout North America. Although corn and soybean are grown in landscapes that are often highly disturbed, these data suggest that a community of pollinators can persist within them. We suggest approaches to conserving this community based on partnering with activities that aim to lessen the environmental impact of annual crop production.

Birds have long been hypothesized as primary dispersal agents of the hemlock woolly adelgid (Adelges tsugae Annand). Although A. tsugae eggs and mobile first instars (crawlers) have been collected from wild birds, key mechanistic elements necessary for avian dispersal have never been examined. To evaluate the mechanisms of bird-mediated A. tsugae dispersal, we conducted both stationary (i.e., where crawlers must actively disperse) and disturbance (i.e., where crawlers may transfer from substrates due to mechanical abrasion) dispersal trials. For stationary trials, we tested the role of perching duration, ovisac density, and seasonal timing on the rate of crawler transfer to immobile preserved bird mounts at a single site in Connecticut. For disturbance trials, we explored if transfer rates were different when branches were actively brushed against birds. Both stationary and disturbance trials resulted in successful transfers of A. tsugae to bird mounts, with disturbance trials having significantly higher rates of transfers. Crawler counts from stationary trials increased significantly with local ovisac density. Additionally, we found a nonlinear relationship between crawler transfer and experimental week, with crawler transfer highest at the beginning of sampling in May, coinciding with avian spring migration in Connecticut and the emergence of progrediens crawlers, and spiking again near 14 June, when sistens generation crawlers began to emerge. While many aspects of potential avian dispersal of A. tsugae remain unknown, these results suggest that crawler transfer to birds may occur most often when peak crawler emergence coincides with the northward migration of many small passerine bird species.

Onion thrips, Thrips tabaci Lindeman, is a significant pest of onion crops worldwide, but little is known about its patterns of aerial dispersal in the context of abiotic environmental factors. Thrips tabaci adults were passively collected from the air column above onion fields in western New York using clear sticky cards over a series of sampling periods in 2012, 2013, and 2014 while on-site weather conditions were recorded. Results indicated that T. tabaci adult densities on aerial traps during daylight averaged 279 times greater per hour than densities on similar traps at night. Adult dispersal also tended to spike during presunset, indicating that thrips initiated flight diurnally and within 1 h before sunset. Densities of T. tabaci on aerial traps increased significantly as temperature increased above 17 °C and 90% of the thrips were captured between 20.8 and 27.7 °C; no thrips were captured above 30.6 °C. Densities of T. tabaci on aerial traps decreased significantly as wind speed increased, with no thrips captured at winds exceeding 3.8 m/s (13.7 kph). In 2013 and 2014, T. tabaci densities on aerial traps prior to the passage of a cold front (relatively high atmospheric pressure and temperature with low wind speed) were significantly greater than densities after passage of the front, suggesting that T. tabaci disperses on synoptic weather systems.

The seasonal pattern of parasitism by a parasitoid can be influenced by many factors, such as interspecific competition and host instar preference. We conducted field and laboratory experiments to describe the seasonal pattern of parasitism of spruce budworm Choristoneura fumiferana (Clemens) larvae by Tranosema rostrale (Brischke), and to investigate whether this pattern can be explained by interaction with other parasitoid species, or by host instar preference. Larval survival, developmental time, sex ratio, and adult size of T. rostrale developing in different host instars were also measured to further assess the potential importance of host instar on parasitoid life history. Parasitism by T. rostrale increased over the season, reaching the highest rate during the fourth-instar larva, and then decreased again until the sixth-instar. At the same time, parasitism by another parasitoid, Elachertus cacoeciae (Howard), increased over the season, and multiparasitism with T. rostrale suggests potential competition between these two parasitoids. Tranosema rostrale showed no host instar preference when third- to sixth-instar larvae were exposed simultaneously in a manipulative field experiment. The proportion of females emerging from spruce budworm larvae increased over the season; however, no difference in sex ratio was observed in the manipulative field experiment. Only male pupal development time and adult size were marginally increased in fifth-instar spruce budworm larvae. We conclude that T. rostrale's seasonal phenology or competition with E. cacoeciae, but not host instar preference, were possibly responsible for the observed seasonal pattern of parasitism.

Predators and scavengers play a vital role in regulating insect pests, weeds, and vertebrate scat in perennial agroecosystems. Understanding how farm management practices and surrounding habitat influence these beneficial ecosystem services contributes to our understanding of these complex ecological systems and guides future management decisions. In a mensurative 2-yr study, we determined how different pest management strategies and surrounding forest composition influenced levels of sentinel insect pupae, weed seeds, and deer scat (feces) removal. Removal of these bioresources was measured within 12 commercial lowbush blueberry fields during 2011 and 2012; farms differed in surrounding landscape composition and farm management strategies. Both the removal of sentinel pupae and scat, was significantly higher within field interiors than at field edges and within adjacent forests. Additionally, farm management strategy interacted with field position to result in significantly higher scat removal in conventional field interiors than organic field interiors. Surrounding forest composition had variable effects on removal of materials. Our results indicate higher levels of activity within field centers as opposed to field edges; this is contrary to what has been observed in other perennial cropping agroecosystems.

Does climatic niche change during invasion? We used Digitonthophagus gazella (F.) as a model to test the niche conservatism hypothesis and found out that climatic niche was stable between native and invasive ranges of this exotic dung beetle. Distribution maps based either on native or invasive occurrences exhibited the same picture of a widespread dung beetle restricted by areas with low precipitation and cold temperatures. We believe that this species opportunistic behavior is one of the main reasons behind this pattern. We suggest that use of native occurrences to predict a potential risk of biological invasions is a useful tool.

Environmental heterogeneity is a major factor influencing the spatial distribution of organisms. Due to intimate relationships with their hosts, parasitic insects are inclined to be even more sensitive to variations. This study aimed to verify the relationship between spatial distribution of Mutillidae, potential hosts, and the effect of heterogeneity in the distribution of both, testing the hypotheses: i) the spatial distribution of mutillids depends on the distribution of hosts and ii) variation in environmental heterogeneity affects the distribution of both. Sampling was conducted in four fragments of the Cerrado. We collected Hymenopteran specimens from 25 plots of one hectare using 18 Malaise traps throughout one year, totalizing 32,400 trap-hours. Female Mutillidae were hand collected at all sampling points, for a total of 450 man-hours. At each hectare plot, we obtained the environmental variables from nine plots of 25 m². A total of 1,089 individuals were collected (Apidae: 311; Crabronidae: 165; Shpecidae: 84; Vespidae: 229) belonging to 127 species of potential hosts (bees and wasps) and 300 individuals (42 species) of Mutillidae. Leaf-litter depths showed significant relation in host–parasitoid distribution. The spatiotemporal distribution followed the predator–prey model for Mutillidae, and environmental heterogeneity was a factor that determined the structure of the host–parasitoid community. The results suggest an intense relationship between the Mutillidae and Crabronidae, as well as Sphecidae and two Apidae subfamilies (Halictinae and Colletinae). These families and subfamilies present behavior in which they build nests in aggregations even each female being solitary. Crabronidae is considered the best potential host for Mutillidae.

Crop rotation alters agroecosystem diversity temporally, and increasing the number of crops in rotation schemes can increase crop yields and reduce reliance on pesticides. We hypothesized that increasing the number of crops in annual rotation schemes would positively affect ground-dwelling beneficial arthropod communities. During 2012 and 2013, pitfall traps were used to measure activity-density and diversity of ground-dwelling communities within three previously established, long-term crop rotation studies located in Wisconsin and Illinois. Rotation schemes sampled included continuous corn, a 2-yr annual rotation of corn and soybean, and a 3-yr annual rotation of corn, soybean, and wheat. Insects captured were identified to family, and non-insect arthropods were identified to class, order, or family, depending upon the taxa. Beneficial arthropods captured included natural enemies, granivores, and detritivores. The beneficial community from continuous corn plots was significantly more diverse compared with the community in the 2-yr rotation, whereas the community in the 3-yr rotation did not differ from either rotation scheme. The activity-density of the total community and any individual taxa did not differ among rotation schemes in either corn or soybean. Crop species within all three rotation schemes were annual crops, and are associated with agricultural practices that make infield habitat subject to anthropogenic disturbances and temporally unstable. Habitat instability and disturbance can limit the effectiveness and retention of beneficial arthropods, including natural enemies, granivores, and detritivores. Increasing non-crop and perennial species within landscapes in conjunction with more diverse rotation schemes may increase the effect of biological control of pests by natural enemies.

Impacts of habitat loss and fragmentation on specialist herbivores have been rarely addressed. Here we examine the structure of plant and galling insect assemblages in a fragmented landscape of the Atlantic forest to verify a potential impoverishment of these assemblages mediated by edge effects. Saplings and galling insects were recorded once within a 0.1-ha area at habitat level, covering forest interior stands, forest edges, and small fragments. A total of 1,769 saplings from 219 tree species were recorded across all three habitats, with differences in terms of sapling abundance and species richness. Additionally, edge-affected habitats exhibited reduced richness of both host-plant and galling insects at plot and habitat spatial scale. Attack levels also differed among forest types at habitat spatial scale (21.1% of attacked stems in forest interior, 12.4% in small fragments but only 8.5% in forest edges). Plot ordination resulted in three clearly segregated clusters: one formed by forest interior, one by small fragments, and another formed by edge plots. Finally, the indicator species analysis identified seven and one indicator plant species in forest interior and edge-affected habitats, respectively. Consequently, edge effects lead to formation of distinct taxonomic groups and also an impoverished assemblage of plants and galling insects at multiple spatial scales. The results of the present study indicate that fragmentation-related changes in plant assemblages can have a cascade effects on specialist herbivores. Accordingly, hyperfragmented landscapes may not be able to retain an expressive portion of tropical biodiversity.

Tropical peat swamp forests in Southeast Asia account for approximately 72% of global peatland. However, extensive forest exploitation following peat drainage for agricultural expansion has been leading to catastrophic peat fires. In this study, we compared the termite assemblage in burnt and unburnt peats in Sumatra, Indonesia. We also identified which taxonomic group is particularly resistant to fire disturbance and the traits that correlate with its persistence in fire-impacted peatlands. Overall, the termite species richness in fire-impacted peats was up to 40% lower than that of the total species found in peat swamp forests. Although the estimated species richness values in fire-impacted peats and peat swamp forests were not significantly different, fire changed termite community structure significantly. Only termites of the family Rhinotermitidae survived in the fire event, whereas members of the Termitidae that were reportedly resilient to fire and open habitats elsewhere disappeared during the fire events. The rhinotermitids found in the burnt sites were exclusively wood nesters. This suggests that the desiccation tolerance of termites in open habitat is not the simple underlying survival strategy, but tree branches and barks might have provided a refuge from heat during fire. The result also suggests that the high similarity in species composition in recently burnt peats and long burnt peats implies low species turnover. Thus, regardless of how much time had passed since the fire-impacted peats were abandoned or cultivated, the increase in habitat complexity did not favor colonization by the forest-dependent group.

The life history costs of living in microbially dense environments can be high. To assess the importance of these costs for natural selection, it is necessary to know how costs vary with environmental conditions. Adult burying beetles prepare vertebrate carcasses of varying age and states of deterioration as a resource for their young. In the present study, Nicrophorus orbicollis Say females were presented with either fresh or aged (80 h) large carcasses (30–39 g) to examine effects on their lifetime reproductive success (four reproductive attempts) and survival. Reproductive success and survival were also measured for female offspring that developed on fresh and aged carcasses. Carcass age had no measurable effect on lifetime reproductive output or life span of either parents or their adult offspring. In a separate experiment using medium-sized carcasses (22–24 g), the reproductive performance of females in a single reproductive attempt was negatively affected by carcass age (13.9% less brood mass). The results suggest that the costs of using a single older carcass are relatively minor when measured over a lifetime. Alternative costs of using older carcasses and explanations for the complex antimicrobial traits of burying beetles are discussed.

A 4-yr study was done to analyze seasonal patterns underlying host plant–fruit fly–parasitoid interactions in a secondary forest in the Argentinean Yunga and its importance for the implementation of conservation and augmentative biological control. Larval–pupal hymenopteran parasitoids associated with all host plants and fruit fly species were identified and the seasonal occurrence of fruit, infestation levels, parasitism percentage, and relative parasitoid abundance were determined. Three fruit fly species in two genera were found in association with surveyed plants, two of which (Ceratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann)) are of major economic importance. Infestation levels were strongly influenced by environmental factors and peak fruit availability. Five fruit fly parasitoid species were recovered from fly pupae, four braconid species, and one figitid. Time windows for fruit fly population growth were pinpointed. Based on results, the present analysis proposes an effective fruit fly biological control strategy tailored for the northwestern Argentinean citrus-producing area.

Although granivorous ants are known to collect weed seeds from cropping areas in Australia, the fate of these seeds has not been adequately investigated. Seeds of annual ryegrass (Lolium rigidum Gaud.) and wild radish (Raphanus raphanistrum L.) were placed around the nests of five native ant species (Iridomyrmex greensladei Shattuck, Rhytidoponera metallica Smith, Melophorus turneri Forel, Monomorium rothsteini Forel, and Pheidole hartmeyeri Forel) and tracked continuously over a 24-h period. Removal rates and seed preference of the ant species were evaluated. Ant nests were then excavated to determine the placement of seeds that were taken into each nest. Seed preference, seed removal efficiencies, activity, and seed storage all varied between the ant species. Annual ryegrass seed was collected by three species of ants and was removed from the soil surface more efficiently than wild radish seed. Most ant species stored seed below ground at a depth that is inhibitory to emergence, thereby potentially removing that portion of seed from the seed bank, but some seed was placed at germinable depths. Pheidole hartmeyeri was identified as a likely biological control agent for annual ryegrass seeds and wild radish, while Me. turneri and Mo. rothsteini have potential as biocontrol agents for annual ryegrass, but further research is needed.

Liriomyza huidobrensis (Blanchard) is a serious invasive pest of potato in Korea. In sessile insect herbivores like leafminer flies, host plant choice is a critical decision made by adults for offspring survival, and one that is often influenced by host plant quality. In annual host plants like potato, leafminer choice is sometimes influenced by cultivar characteristics. To determine the basis of host selection, the odor and feeding preferences of adult L. huidobrensis were examined using a five-arm olfactometer offering a choice of five different potato cultivars: ‘Chubeak’, ‘Seohong’, ‘Goun’, ‘Dejima’, and ‘Sumi’. Preferences of adult leafminers varied significantly among potato cultivars. Liriomyza huidobrensis showed a preference for the Goun cultivar in both olfactory and adult feeding tests. When measured 2 wk after release onto actual plants, plant damage ratings and the number of mines were consistent with the feeding preference results. Further studies should examine the influence of cultivar characteristics on larval fitness and adult longevity to develop a resistant potato cultivar through the selection behavior of leafminers.

Bumble bees (genus Bombus) are globally important insect pollinators, and several species have experienced marked declines in recent years. Both nutritional limitation and pathogens may have contributed to these declines. While each of these factors may be individually important, there may also be synergisms where nutritional stress could decrease pathogen resistance. Understanding interactions between bumble bees, their parasites, and food availability may provide new insight into the causes of declines. In this study, we examined the combined impacts of pollen and nectar limitation on Crithidia, a common gut parasite in Bombus impatiens Cresson. Individual worker bees were inoculated with Crithidia and then assigned in a factorial design to two levels of pollen availability (pollen or no pollen) and two nectar sugar concentrations (high [30%] or low [15%] sucrose). We found that lack of pollen and low nectar sugar both reduced Crithidia cell counts, with the most dramatic effect from lack of pollen. Both pollen availability and nectar sugar concentration were also important for bee survival. The proportion of bees that died after seven days of infection was ∼25% lower in bees with access to pollen and high nectar sugar concentration than any other treatment. Thus, nectar and pollen availability are both important for bee survival, but may come at a cost of higher parasite loads. Our results illustrate the importance of understanding environmental context, such as resource availability, when examining a host–parasite interaction.

Plodia interpunctella (Hübner, 1813) is a polyphagous and key pest of different stored products worldwide. The lethal and sublethal effects of essential oils of Artemisia khorassanica Podl. and Vitex pseudo-negundo (Hausskn) were studied on P. interpunctella. The chemical constituents of the essential oils were also assessed using gas chromatography–mass spectrometry. Assays showed that the fumigant toxicity of A. khorassanica (LC₅₀: 9.60 μl/liter air) was higher than V. pseudo-negundo (LC₅₀: 23.05 μl/liter air). Moreover, the speed of mortality caused by A. khorassanica oil (LT₅₀: 2.07 h) was higher than V. pseudo-negundo (LT₅₀: 3.11 h). To assess the sublethal effects of the essential oils, adult moths were exposed to the LC₃₀ of each essential oil, and life table parameters and energy contents of the surviving P. interpunctella were studied. Exposure to sublethal concentration of A. khorassanica negatively affected the life table of P. interpunctella, and also the protein, lipid, and glycogen contents of the larvae that came from treated adults. Vitex pseudo-negundo also affected lipid, protein, and glycogen contents of P. interpunctella. The intrinsic rate of increase (r_m), finite rate of increase (k), and doubling time (DT) were not significantly different between control and V. pseudo-negundo treatment. According with these results, both tested essential oils, especially one extracted from A. khorassanica, have potential applications for the integrated management of P. interpunctella.

The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive pest from Asia that feeds on many agricultural crops in the United States, including blueberries. Yet, the effects of H. halys feeding on fruit chemistry and induced resistance to insects remain unknown. Here we hypothesized that frugivory by H. halys changes fruit chemical composition, which in turn affects insect feeding behavior. In field experiments, blueberry fruit was either mechanically injured or injured by 0 (control), 2, 5, or 10 H. halys. Total soluble solids (°Brix) and anthocyanin and phenolic content in injured and uninjured fruits, as well as their effects on feeding behavior by conspecifics, were measured subsequently in the laboratory. Results showed lower °Brix values in injured fruit as compared with uninjured fruit. Fruit injured by 2 and 5 H. halys also had 32 and 20% higher total phenolics, respectively, than the uninjured controls. The proportions of the anthocyanins derived from delphinidin, cyanidin, and petunidin increased, whereas those from malvidin decreased, in fruit after mechanical wounding and frugivory by H. halys. In dual-choice tests, H. halys fed more often on uninjured fruit than those previously injured by conspecifics. These results show that frugivory by H. halys reduces the amounts of soluble solids, alters anthocyanin ratios, and increases levels of phenolics, and, as a result, injured fruits were a less preferred food source for conspecifics. To our knowledge, this is the first study to investigate the effects of frugivory on fruit chemistry and induced fruit resistance against a fruit-eating herbivore.

Earlier studies have shown that Tomato spotted wilt virus (TSWV) influences the biology, performance, and behavioral patterns of its vector Frankliniella occidentalis Pergande. In this study, using Capsicum annuum L. as the host plant, we aimed to determine the manipulation of F. occidentalis by TSWV through switching of the diet (+ or –TSWV) during vector's development. Behavioral patterns, fitness, as well as vector performance were evaluated. The specific parameters investigated included longevity/survival, fecundity, development time, feeding, and preferential behavior. F. occidentalis were reared on either TSWV-infected (exposed) or healthy leaves (non-exposed) throughout their larval stages. The emerging adults were then individually transferred to either healthy or TSWV-infected leaf disks. This resulted into four treatments, consisting of exposed or non-exposed thrips reared on either infected or healthy leaf disks as adults. All F. occidentalis exposed to TSWV in their larval stages had shorter development time regardless of the adults' diet. Whereas, the ones that were later reared on healthy leaf disks as adults recorded the highest longevity and reproduction rate. Furthermore, adults of F. occidentalis that were exposed to TSWV in their larval stages showed preference toward healthy leaf disks (–TSWV), whereas the non-exposed significantly preferred the infected leaf disks (+TSWV). These are further indications that TSWV modifies the nutritional content of its host plants, which influences vector's biology and preferential behavior, in favor of its multiplication and dispersal. The findings offer additional explanation to the often aggressive spread of the virus in crop stands.

A 3-yr study was conducted to determine the degree of aggregation of stink bugs and boll injury in cotton, Gossypium hirsutum L., and their spatial association with a multispectral vegetation index (normalized difference vegetation index [NDVI]). Using the spatial analysis by distance indices analyses, stink bugs were less frequently aggregated (17% for adults and 4% for nymphs) than boll injury (36%). NDVI values were also significantly aggregated within fields in 19 of 48 analyses (40%), with the majority of significant indices occurring in July and August. Paired NDVI datasets from different sampling dates were frequently associated (86.5% for weekly intervals among datasets). Spatial distributions of both stink bugs and boll injury were less stable than for NDVI, with positive associations varying from 12.5 to 25% for adult stink bugs for weekly intervals, depending on species. Spatial distributions of boll injury from stink bug feeding were more stable than stink bugs, with 46% positive associations among paired datasets with weekly intervals. NDVI values were positively associated with boll injury from stink bug feeding in 11 out of 22 analyses, with no significant negative associations. This indicates that NDVI has potential as a component of site-specific management. Future work should continue to examine the value of remote sensing for insect management in cotton, with an aim to develop tools such as risk assessment maps that will help growers to reduce insecticide inputs.

Generalist predators play an important role in many terrestrial systems, especially within agricultural settings, and ants (Hymenoptera: Formicidae) often constitute important linkages of these food webs, as they are abundant and influential in these ecosystems. Molecular gut content analysis provides a means of delineating food web linkages of ants based on the presence of prey DNA within their guts. Although this method can provide insight, its use on ants has been limited, potentially due to inhibition when amplifying gut content DNA. We designed a series of experiments to determine those ant organs responsible for inhibition and identified variation in inhibition among three species (Tetramorium caespitum (L.), Solenopsis invicta Buren, and Camponotus floridanus (Buckley)). No body segment, other than the gaster, caused significant inhibition. Following dissection, we determined that within the gaster, the digestive tract and crop cause significant levels of inhibition. We found significant differences in the frequency of inhibition between the three species tested, with inhibition most evident in T. caespitum. The most effective method to prevent inhibition before DNA extraction was to exude crop contents and crop structures onto UV-sterilized tissue. However, if extracted samples exhibit inhibition, addition of bovine serum albumin to PCR reagents will overcome this problem. These methods will circumvent gut content inhibition within selected species of ants, thereby allowing more detailed and reliable studies of ant food webs. As little is known about the prevalence of this inhibition in other species, it is recommended that the protocols in this study are used until otherwise shown to be unnecessary.

Megacopta cribraria (F.) (Hemiptera: Plataspidae) is an established pest of soybean, Glycine max (L.) Merrill, in the southeastern United States. Populations of this pest in soybean are typically estimated using sweep nets, a time-consuming procedure. Cross-vane traps may provide an alternative to using sweep nets. The relationship between trap and sweep-net sampling, and the effect of distance from field edges on M. cribraria densities were studied in 2013 and 2014. Adults were detected in the traps up to 3 wk before they were present in the sweep-net samples. Adults and nymphs collected from trap and sweep-net sampling decreased from the field edge toward the field interior. Across all dates and distances, there was a strong positive association between the two sampling methods (r = 0.60), but only 36% of location analyses by week showed significant association. Females collected using both sampling methods were dissected and rated based on egg development. Female populations of all reproductive maturities dispersed into soybean, but proportions varied with sampling method. Results provide a foundation for work into understanding dispersal cues, with implications for management in soybean. Cross-vane traps may serve as an early-season tool to monitor populations, but more studies are needed before robust sampling recommendations can be defined.

The chemical structures of aggregation-sex pheromones of longhorned beetles (Coleoptera: Cerambycidae) are often conserved among closely related taxa. In the subfamily Lamiinae, adult males and females of several species are attracted by racemic blends of (E)-6,10-dimethyl-5,9-undecadien-2-ol (termed fuscumol) and the structurally related (E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (fuscumol acetate). Both compounds have a chiral center, so each can exist in two enantiomeric forms. Males of many species of longhorned beetles only produce one stereoisomer of each pheromone component, and attraction may be reduced by the presence of stereoisomers that are not produced by a particular species. In a previous publication, analysis of headspace volatiles of adult beetles of the lamiine species Astyleiopus variegatus (Haldeman) revealed that males sex-specifically produced (S)-fuscumol and (S)-fuscumol acetate. Here, we describe field trials which tested attraction of this species to single enantiomers of fuscumol and fuscumol acetate, or to blends of enantiomers. We confirmed attraction of A. variegatus to its species-specific blend, but during the course of the trials, found that several other species also were attracted. These included Aegomorphus modestus (Gyllenhall), attracted to (S)-fuscumol acetate; Astylidius parvus (LeConte), attracted to (R)-fuscumol; Astylopsis macula (Say), attracted to (S)-fuscumol; and Graphisurus fasciatus (DeGeer), attracted to a blend of (R)-fuscumol and (R)-fuscumol acetate. These results suggest that chirality may be important in the pheromone chemistry of lamiines, and that specific stereoisomers or mixtures of stereoisomers are likely produced by each species.

The rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), is a serious pest species both in its original distribution region of northern America and its invaded regions of eastern Asia and southern Europe. The odorant-binding proteins (OBPs) and the chemosensory proteins (CSPs) play important roles in host and mate locating, thus might play a significant role in the success of the species as an invader, which has not been characterized yet. We identified 10 OBPs and 5 CSPs in L. oryzophilus and investigated the expression profiles of these genes in various tissues by quantitative real-time PCR. Five classic OBPs were predominantly expressed in the antennae. CSPs were expressed ubiquitously with particularly high transcript levels in antennae, legs, and wings. Three antenna-specific OBPs (LoOBP1, 8, 11) were up-regulated following 1–3 d of food deprivation and down-regulated afterward. These findings suggest most classic OBPs are likely involved in chemoreception whereas CSPs as well as the minus-C OBPs may have broader physiological functions, which in turn may help to understand the molecular aspects of chemical communication in this invasive insect.

Climate warming provides a challenge for small insects persisting in cold seasons through diapause because they fail to accumulate and maintain adequate reserves to complete this stage successfully. One way of understanding this challenge is to follow physiological changes in these insects under higher temperatures, including the consumption and allocation of energy reserves during and after diapause. We simulated autumn and spring warming conditions to study carbohydrate consumption dynamics during diapause–post-diapause periods by monitoring shifts in carbohydrate levels in a facultative diapause species, the peach fruit moth Carposina sasakii Matsumura (Lepidoptera: Carposinidae). We found carbohydrates were rapidly consumed in the postdiapause phase, which might lead to a trade-off in the allocation of energy reserves between diapause maintenance and post-diapause development. This suggests that temperature increases in autumn and spring may alter diapause maintenance and post-diapause development through changing carbohydrate levels.

The harlequin bug, Murgantia histrionica (Hahn), is a serious pest of brassicaceous vegetables in southern North America. While this insect is limited in its northern range of North America, presumably by severe cold winter temperatures, specific information on its cold hardiness remains unknown. We determined the supercooling points (SCPs) for Maryland and Virginia adult populations and found no significant difference among these populations. SCPs were similar for adults (x̄ = –10.35 °C; σ_X = 2.54) and early and late instar (x̄ = –11.00 °C; σ_X = 4.92) and between adult males and females. However, SCPs for first instars (x̄ = –21.56 °C; σ_X =1.47) and eggs (x̄ = –23.24°C; σ_X =1.00) were significantly lower. We also evaluated field survival of overwintering harlequin bug adults during extreme cold episodes of January 2014 and January 2015, which produced widespread air temperatures lower than –15 °C and subfreezing soil temperatures in the Mid-Atlantic Region. After the 48-h episode in 2014, bug mortality in exposed field sites averaged 88%, compared to <5% mortality of bugs sheltered in an unheated greenhouse (recorded minimum temperature 4.4 °C). After the 2015 episode, ∼80% of adults that were established in the field the previous November and then sheltered in an unheated garage during the episode, died, in contrast to 96% mortality in exposed field sites. Our results provide new information on M. histrionica overwintering biology, and thermal limitations to its distribution, which leads to improved predictive capabilities to forecast pest severity.

A comparison of 95 species of Central European moths, representing 11 families and inhabiting various habitats, was carried out in order to detect the potential impact of biotope on the ultraviolet (UV) light reflectance of their wings. Based on digitized photographs taken under UV light conditions, a phylogeny-controlled redundancy analysis relating UV reflectance to preferred habitat type (xerophilous, mesophilous, and hygrophilous) and habitat openness (open, semiopen, and closed) was carried out. Species preferring hygrophilous habitats displayed significantly higher UV wing reflectance than species inhabiting xerothermic and mesic habitats, and this pattern remained significant even after controlling for phyletic relationships. In contrast, UV wing reflectance displayed no pattern related to habitat openness. Given the higher UV reflectance of water and humid surfaces, we interpret these results, which are based on the first comprehensive sampling of UV reflectance in Central European moths, in terms of predator avoidance under habitat-specific light conditions. We conclude that the moisture content of the environment may markedly contribute to the variation of appearance of moth wings for better imitation habitat characteristics and therefore to increase protection.

Arsenic (As) can play an important role in the contamination of soils, waters, and air. The toxicity of As to most organisms is well established, but little is known about the interactions between environmental As and terrestrial invertebrates and the fate of As through trophic levels. Pteris vittata L. (Polypodiales: Pteridaceae), a fern that hyperaccumulates arsenic, serves as a potential mechanism to facilitate interactions between environmental arsenic and other biota. We compared invertebrate arsenic concentrations (hereafter as [As]) and bioaccumulation factors associated with soil and fern [As] to elucidate relationships between invertebrate and environmental As exposure. We collected invertebrates in pitfall traps from field sites associated with P. vittata, and identified them to order for whole body arsenic analysis and subsequently family for classification into functional feeding groups. We found that overall [As] in invertebrates increased with soil [As], but not with fern [As]. The absence of a relationship between fern [As] and invertebrate [As] may indicate invertebrates are avoiding the fern. Individual taxonomic groups significantly differed in whole body [As], and individual taxa also varied in their relationship between whole body [As] relative to soil and fern [As]. Overall invertebrate abundance decreased as invertebrate [As] load increased but varied across taxa. One particular herbivore, Callopistria floridensis (Florida fern caterpillar), associated with relatively low environmental As exposure contained over 4,000 mg kg^–1As. Our results show that As bioaccumulates into higher trophic levels and invertebrate body [As] covary with exposure to naturally occurring environmental [As] associated with P. vittata.

Most parasitoids depend on carbohydrate-rich foods to maximize their longevity and reproduction potential. These food resources are commonly from floral nectar, extra-floral nectar, and honeydew, which contain monosaccharides, disaccharides, and oligosaccharides. Here, we report an experiment to explore the effects of 12 naturally occurring sugars on the gustatory response, longevity, and fecundity of Trichogramma japonicum and Trichogramma chilonis. These two parasitoid species differed in their responses to the tested sugars. Trichogramma japonicum showed a high gustatory response to eight sugars, but T. chilonis to only six. However, only fructose, glucose, and sucrose increased the longevity of T. japonicum, and only glucose enhanced the fecundity. For T. chilonis, fructose, galactose, gluctose, maltose, melibiose, sucrose, and melezitose prolonged the longevity and increased fecundity. Furthermore, female T. japonicum benefitted much less from the ingestion of sugars when compared with female T. chilonis. For T. japonicum, feeding on suitable sugars, longevity was increased by a factor of 1.8–2.0, and fecundity by a factor of 1.5. In T. chilonis, longevity increased by a factor of 2.9–5.2 and fecundity by 2.7–4.0. Thus, providing the right sugars to the parasitoids will help to enhance the biological control efficacy of Trichogramma, and T. chilonis in particular.

A viral gene, CpBV-CST1, was identified from a polydnavirus Cotesia plutellae bracovirus (CpBV). Its protein product was significantly toxic to lepidopteran insects. This study generated a transgenic tobacco plant expressing CpBV-CST1. Expression of transgene CpBV-CST1 was confirmed in T1 generation (second generation after transgenesis) in both mRNA and protein levels. Young larvae of Spodoptera exigua (Hübner) suffered high mortalities after feeding on transgenic tobacco. All 10 T1 transgenic tobacco plants had no significant variation in speed-to-kill. In order to further explore insect resistance of these transgenic tobaccos, bioassays were performed by assessing antixenosis and antibiosis. S. exigua larvae significantly avoided T1 plants in a choice test. Larvae fed with T1 plant exhibited significant decrease in protease activity in the midgut due to consuming CpBV-CST1 protein produced by the transgenic plant. Furthermore, the transgenic tobacco exhibited similar insect resistance to other tobacco-infesting insects, including a leaf-feeding insect, Helicoverpa assulta, and a sap-feeding insect, Myzus persicae. These results demonstrate that a viral cystatin gene can be used to develop insect-resistant transgenic plant, suggesting a prospective possibility of expanding the current transgenic approach to high-valued crops.