Homalodisca vitripennis (Germar), a vector of Xylella fastidiosa, is associated with citrus plantings in California. Infested citrus orchards act as a source of vectors to adjacent vineyards where X. fastidiosa causes Pierce's disease. An analysis of the pattern and rate of movement of H. vitripennis and its egg parasitoid, Gonatocerus ashmeadi Girault, was conducted in a citrus orchard by using a protein mark-capture technique to quantify movement and net dispersal rates in the experimental areas. Treatments included irrigation at 100% of the crop evapotranspiration rate (ET_c), 80, and 60% ET_c. Sex-specific net dispersal rates showed that H. vitripennis males and females moved consistently and contributed equally to the level of population change within treated areas. Trees irrigated at 60% ET_c were the least preferred by H. vitripennis. Among all protein-marked individuals captured in the 60% ET_c treatment, ≈75 and 88% in 2005 and 2006, respectively, were inflow individuals. Movement toward less preferable plants indicates that in agricultural landscapes dominated by perennial monocultures, there is a random component to H. vitripennis movement, which may result from the inability of H. vitripennis to use plant visual cues, olfactory cues, or both to make well-informed long-range decisions. The 80% ET_c areas were a significant source of adult H. vitripennis and G. ashmeadi compared with the other treatments. Colonization rates by parasitoids were synchronized with the spatiotemporal distribution of H. vitripennis eggs. Results suggest that H. vitripennis movement from citrus into adjacent vineyards could be a result of random dispersal rather than oriented movement in response to host-plant characteristics.

We describe seasonal patterns of parasitism by Telenomus coloradensis Crawford, Telenomus droozi Muesebeck, Telenomus flavotibiae Pelletier (Hymenoptera: Scelionidae), and Trichogramma spp. (Hymenoptera: Trichogrammatidae), egg parasitoids of the hemlock looper, Lambdina fiscellaria (Guenée) (Lepidoptera: Geometridae), after a 3-yr survey of defoliated stands in the lower St. Lawrence region (Quebec, Canada). Results from sentinel trap sampling indicate that T. coloradensis and T. droozi are the most common species, whereas parasitism by T. flavotibiae and Trichogramma spp. is rare. Telenomus coloradensis and T. droozi show similar seasonal periods of parasitism, both species being active in early spring (late April) at temperatures as low as 4°C. Using thermal threshold (T₀) and thermal constant (K) for immature development of T. coloradensis males and females from egg to adult emergence, we estimated that the spring progeny emerges in the middle of the summer while hemlock looper eggs are absent from the forest environment. Parasitoid females would then mate and remain in the environment to 1) exploit alternate host species, 2) enter into quiescence and later parasitize eggs laid by hemlock looper females in the fall, 3) enter into a reproductive diapause and parasitize hemlock looper eggs only the next spring, or all of these. Although previous studies have shown that T. coloradensis can overwinter in its immature form within the host egg, our field and laboratory results indicate that in the lower St. Lawrence region, this species principally enters diapause as fertilized females, with a mean supercooling point of -30.6°C in the fall.

Tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), overwinter as diapausing adults in North America. Overwintering adults were collected near Stoneville, MS from blooming henbit, Lamium amplexicaule L., and from plant debris during December and January and dissected to determine their reproductive status. Averaged over four winters, male and female tarnished plant bugs collected from henbit terminated diapause at a significantly higher rate than males and females from plant debris during each week of December and the first week of January. Both sexes in each habitat were nearly all reproductive by the end of January. Adults overwintering in plant debris terminated diapause during January in the absence of a food stimulus in all 5 yr studied. This emergence was thought to be controlled by an internal clock. Laboratory and field studies showed that emergence from diapause could be influenced by food, sex, and temperature. Adults overwintering on a suitable food source, blooming henbit, terminated diapause during December in the 4 yr studied, and males terminated diapause more rapidly than females. Food quality was important in emergence from diapause, and females on blooming henbit terminated diapause at a significantly higher rate than females on nonblooming mustard, Brassica juncea (L.) Cosson. Laboratory tests showed that diapausing adults reared in the laboratory and held at a diapause-maintaining photoperiod of 10:14 (L:D) h could be terminated from diapause by using food and temperature stimuli. The lower thermal threshold for development to reproductive adults was found to be near 10°C. The ability of diapausing adults to respond to food and temperature stimuli in December can enable tarnished plant bugs to take advantage of warm winters and winter hosts to produce a new generation earlier.

We used life table analyses to investigate age specific mortality and to better understand the population dynamics of the red oak borer, Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae). We continually sampled populations within 177 trees at primarily two sites in the Ozark National Forest in Arkansas throughout three (2-yr) generations. The first cohort (adults emerged in 2003) was sampled during a severe population outbreak, whereas the second and third (2005 and 2007) were sampled during the population crash that followed. Generation mortality was 94% in 2003 and 99% in both 2005 and 2007. Estimates of apparent mortality indicated that the E. rufulus population crash likely occurred during or before the first overwintering period (2003–2004) of the generation that emerged as adults in 2005. We found limited evidence for density dependent mortality, which suggest that intraspecific competition after the first active feeding period was apparently not an important mortality factor during E. rufulus development. Life tables revealed that E. rufulus larvae generally experienced the greatest apparent mortality during the second summer of active feeding (80–94%) when larvae were feeding in, and moving between phloem and sapwood. The least apparent mortality was incurred during the following spring and early summer (26–67%) when late stage larvae and pupae were deepest and most protected within sapwood or heartwood tunnels. We found very little evidence for mortality from associated species. Scarring of vascular tissue in response to E. rufulus feeding occurred during early life stages and may be an important tree resistance mechanism and E. rufulus mortality factor.

The persistence of aquatic insect populations in streams depends on the recruitment of larval populations from egg masses deposited by adults, especially after disturbance. However, recruitment of aquatic populations by oviposition is a process that remains unstudied in streams and rivers. The objectives of our study were to document flying and oviposition patterns of aquatic insects in a high altitude tropical stream during both dry and wet seasons. In particular we studied 1) richness and abundance of adult forms of aquatic insects flying and ovipositing; 2) number of eggs (oviposition pattern), egg mass identity, and morphology; and 3) substrate preferences by ovipositing females. We found 2,383 aquatic insects corresponding to 28 families, with dipterans representing 89% of total individuals collected. Adult insects had lower richness (28 taxa) than larval diversity (up to 52 taxa) and distinct community composition. Richness and relative abundance of most taxa (adults) were not significantly different between seasons, behaviors, diel period, or all three. During both sampling periods we found females with eggs in a total of 15 different families (13 in the dry season and 14 in the wet season). There were no significant differences in the proportion of females with eggs between seasons, diel periods, or different behaviors (flying versus ovipositing traps) of the different female taxa. Few types of egg masses were found in rocks at the stream during both seasons, and most egg masses found corresponded to families Baetidae and Chironomidae. Finally, we provide the first description of eggs masses (size, shape, color, and number of eggs per female) of gravid females (10 taxa) and those found in the stream substrate (six taxa) of Andean macroinvertebrates. This is the first study reporting oviposition, adult diversity, and oviposition patterns of aquatic insects in the Andean region.

Surveys in 1974 of bumble bee species distributions along elevational gradients (Pyke 1982) were revisited to reevaluate the original conclusion that coexistence of bumble bee species can be ascribed to niche differentiation, primarily on the basis of proboscis lengths and the associated corolla lengths of visited flowers. Each bee species largely visited a few plant species, which were preferred relative to other species. Bee proboscis length was correlated with average corolla length of visited flowers, but not when species with relatively long and short proboscises were considered separately. Bumble bee abundance was affected by presence or absence of major plant species and, contrary to the interpretation of Pyke (1982), elevation, with neither factor dominating. Multimodal distributions of proboscis lengths and altitudinal replacement of bee species of similar proboscis length were consistent with the original hypothesis that bumble bee species compete for floral resources, especially nectar, and cannot coexist if proboscis lengths are too similar, unless one species is a “nectar robber” and hence has exclusive use of some floral resources. However, observed overlap in elevational distributions of bumble bee species with similar proboscis length cannot be reconciled with this hypothesis unless other phenomena are invoked.

In September of 2004, Sirex noctilio F. (Hymenoptera: Siricidae) was detected in New York State and later found to be established over a larger area, including parts of southeastern Canada and the northeastern United States. A key component of S. noctilio detection and management plans in other parts of the world where S. noctilio has become established are chemically girdled trap trees. Trap tree usage in North America is confounded by the presence of diverse communities of organisms that inhabit dead and dying trees. We trapped a portion of the arboreal insect community arriving at Pinus resinosa Ait. and Pinus sylvestris L., trap trees girdled 3 mo before (April), one month before (June), and at S. noctilio flight (July) in central New York. Multiple-funnel traps attached to trap trees captured 30,031 individuals from 109 species of Scolytinae, Cerambycidae, and Siricidae. Ipspini (Say) and Ips grandicollis (Eichhoff) accounted for almost 50% of the scolytines captured at trap trees and were present on all girdling dates. Significantly more scolytines and cerambycids were captured on P. sylvestris compared with P. resinosa, but species richness of captured insects did not differ between the two trees. More total and conifer-inhabiting scolytines and cerambycids were captured in traps on trees girdled in April and June and higher observed species richness was found on trees girdled in April and controls. Results from this study suggest a large community of arboreal insects and associated organisms are attracted to chemically girdled trap trees and likely interact with S. noctilio.

Woolly apple aphid, Eriosoma lanigerum (Hausmann), has become a pest of increasing importance in Washington apple orchards in the past decade. The increase in aphid outbreaks appears to be associated with changes in pesticide programs and disruption of biological control. We sampled woolly apple aphid colonies in central Washington apple orchards for natural enemies of this pest from 2006 to 2008. The most common predators encountered were Syrphidae (Syrphus opinator Osten Sacken, Eupeodes fumipennis Thomson, and Eupeodes americanus Wiedemann); Chrysopidae (Chrysopa nigricornis Burmeister); and Coccinellidae (Coccinella transversoguttata Brown and Hippodamia convergens Guérin-Méneville). The specialist syrphid Heringia calcarata Loew was recorded for the first time occurring in Washington apple orchards. The only parasitoid found in aerial colonies of woolly apple aphid was Aphelinus mali Haldeman; root colonies, however, were not parasitized. Identification of important natural enemies provides a better basis for conservation biological control of this pest.

Bronze birch borer (Agrilus anxius Gory) (Coleoptera: Buprestidae), a specialist wood-borer endemic to North America, is prone to periodic outbreaks that have caused widespread mortality of birch (Betula spp.) in boreal and north temperate forests. It is also the key pest of birch in ornamental landscapes. Amenity plantings have extended the distribution of birch in North America, for which we report an updated map. Life history and phenology also are summarized. Larvae feed primarily on phloem tissue of stems and branches, which can girdle and kill trees. Stressors such as drought, elevated temperature, and defoliation predispose trees to bronze birch borer colonization and trigger outbreaks, which implicates the availability of suitable host material in the bottom-up regulation of populations. Stress imposed by climate change may increase the frequency of outbreaks and alter the distribution of birch. Bronze birch borer has a diverse array of natural enemies, but their role in top-down population regulation has not been studied. There is substantial interspecific variation in resistance to this insect. North American species share a coevolutionary history with bronze birch borer and are much more resistant than Eurasian species, which are evolutionarily naive. Potential resistance mechanisms are reviewed. The high susceptibility of Eurasian birch species and climatic similarities of North America and Eurasia create high risk of widespread birch mortality in Eurasia if the borer was inadvertently introduced. Bronze birch borer can be managed in amenity plantings through selection of resistant birch species, plant health care practices, and insecticides.

Aphids harbor a community of bacteria that include obligate and facultative endosymbionts belonging to the Enterobacteriaceae along with opportunistic, commensal, or pathogenic bacteria. This study represents the first detailed analysis of the identity and diversity of the bacterial community associated with the cabbage aphid, Brevicoryne brassicae (L.). 16S rDNA sequence analysis revealed that the community of bacteria associated with B. brassicae was diverse, with at least four different bacterial community types detected among aphid lines, collected from widely dispersed sites in Northern Britain. The bacterial sequence types isolated from B. brassicae showed little similarity to any bacterial endosymbionts characterized in insects; instead, they were closely related to freeliving extracellular bacterial species that have been isolated from the aphid gut or that are known to be present in the environment, suggesting that they are opportunistic bacteria transmitted between the aphid gut and the environment. To quantify variation in bacterial community between aphid lines, which was driven largely by differences in the proportions of two dominant bacterial orders, the Pseudomonales and the Enterobacteriales, we developed a novel real-time (Taqman) qPCR assay. By improving our knowledge of aphid microbial ecology, and providing novel molecular tools to examine the presence and function of the microbial community, this study forms the basis of further research to explore the influence of the extracellular bacterial community on aphid fitness, pest status, and susceptibility to control by natural enemies.

Newly introduced phytophagous insects can affect native and introduced plant species. If the native plant species evolved without undergoing selective pressure from these insects, insectplant interactions may be different for native and introduced plant species. In particular, this difference may involve mechanisms of plant defense against herbivores. If native plants lack such mechanisms, they may be more palatable to insects than exotic plants. On isolated sub-Antarctic islands, native plant species have evolved in the absence of sap-feeding insects, subsequently introduced a few decades ago. In this study, performance of an introduced aphid species, Myzus ascalonicus Doncaster, was experimentally compared on three native [Pringlea antiscorbutica Hook.f, Acaena magellanica (Lam) Vah, and Leptinella plumosa Hook.f.] and three exotic plant species (Taraxacum officinale F.H. Wigg, Cerastium fontanum Baumg., and Senecio vulgaris L.) found on the Kerguelen Islands. Counts and weights of aphid colonies were 2–7 times higher on native plants than on exotic plants depending on experimental conditions. The results are discussed in light of the possibility of an absence or ineffective defense mechanisms in native plants.

Myrmecochory is a facultative, mutualistic interaction in which ants receive a proteinrich food reward (elaiosome) in return for dispersing plant seeds. In North American northeastern hardwood forests, Aphaenogaster ants are the primary genus dispersing myrmecochorous plants. In these forests, myrmecochores occur in plant guilds of understory spring ephemerals or seasonal greens. This mutualism has been demonstrated tor Aphaenogaster rudis (Emery) and individual plant species, but it has not been demonstrated for other Aphaenogaster species or guilds of myrmecochores as they naturally occur. Aphaenogaster picea (Wheeler) colonies were fed three treatments over 5 mo: 1) a mixture of only elaiosomes from an entire plant guild, 2) a diet of only insect protein and 3) a combination diet of both elaiosomes and insect protein. This experiment investigated two potential hypotheses through which elaiosomes can benefit ants: 1) elaiosome proteins can substitute for protein nutritional requirements when ants are prey-limited, and 2) elaiosome nutrition can supplement insect protein when prey is ample. First, a mixture of elaiosomes from four myrmecochorous plant species provided to A. picea colonies was sufficient to maintain worker production, larval growth, and fat stores when no other food was available. A. picea colonies consuming elaiosomes as their only protein source could be sustained for a growing season (5 mo). Second, colonies fed both elaiosomes and protein did not yield more productive colonies than a control diet of just insect protein. These results support the hypothesis that myrmecochory is indeed a facultative mutualism in which ants take advantage of the protein content of elaiosomes when it is favorable, but when they are not limited by insect prey they do not gain any additional benefit from elaiosomes.

Within a plant species, leaf traits can vary across environmental, genetic, spatial, and temporal gradients, even showing drastic differences within individuals. Herbivory can also induce variation in leaf morphology, defensive structure, and chemistry including nutritional content. Indirect effects of prior insect herbivory on later herbivores have been well documented, but the induction of trait changes after vertebrate herbivory has been little explored. Here, we examined how browsing of spicebush (Lindera benzoin L.), a dominant understory shrub in eastern mesic forests, by whitetailed deer (Odocoileus virginianus L.) altered plant quality and subsequent foliar herbivory by insects. Browsing history explained ≈10% of overall leaf trait variation; regenerated leaves had greater water content and specific leaf area (P = 0.009), but were lower in nitrogen and greater in carbon (P < 0.001), than leaves on unbrowsed plants. However, browsing did not shift terpene chemistry as revealed by GC-MS. In the lab, caterpillars of the specialist spicebush swallowtail (Papilio troilus L.) preferred (P = 0.02) and grew 20% faster (P = 0.02) on foliage from browsed plants; whereas total herbivory in the field, including generalist insect herbivory, was twice as high on unbrowsed plants (P = 0.016). These results suggest that the ecological impacts of deer in forest understories can have cascading impacts on arthropod communities by changing the suitability of host-plants to insect herbivores.

Host plant resistance and biological control are important components of integrated pest management programs. However, plants expressing resistance to herbivores may also have direct or indirect negative effects on natural enemies simultaneously providing pest suppression. Soybean aphids (Aphis glycines Matsumura) are invasive and serious pests of soybean (Glycine max L.) in the United States. Several soybean lines with aphid resistance have been identified, but the long-term impact of these resistant plants on soybean aphid biological control agents is uncertain. In a previous study, we reported that a soybean aphid parasitoid, Binodoxys communis (Gahan) had lower mummy production on resistant plants compared with a near isogenic susceptible soybean line, but the reason for this was unclear. Therefore, we examined three possible mechanisms to explain these findings: 1) resistant plants directly impact wasp emergence and longevity, 2) varying aphid density influences parasitism rates, and 3) resistant plants indirectly affect wasp development through reduced aphid longevity. We found that parasitoids in this study were not directly influenced by resistant cultivais, as there was no difference in wasp adult emergence or longevity between resistant and susceptible plants. There was also no significant effect of aphid density on mummy production over the range of aphid densities we tested. However, aphids on resistant plants had significantly shorter lifespans and were unable to survive long enough to develop into mummies compared with aphids on susceptible plants. We discuss these results and possible implications for integrating biological control and host plant resistance within soybean aphid integrated pest management programs.

Herbivorous insects often move and distribute according to the quality of the plant they are on, and this behavior could influence interactions with plants bred for herbivore resistance. However, when an insect is normally considered sedentary, less is known about the potential importance of movement. We performed experiments to determine if a resistant soybean variety alters the movement and distribution, both within and between plants, of the soybean aphid Aphis glycines Matsumura. We did this by counting apterous aphids on leaves of resistant and susceptible soybean plants across several days. In individual plant tests aphid distribution was different between susceptible and resistant soybeans. Most notably aphids on resistant plants were quickly found off the original leaf on which they were placed and were ultimately distributed throughout the resistant soybean. Aphids on susceptible plants, however, tended to stay on their initial leaf of placement. Follow up experiments indicated this was primarily because of the movement of individuals and not differential demography on various plant parts. In experiments where aphids were able to walk to an adjacent plant there appeared to be a net movement of aphids off resistant plants and on to susceptible plants. Aphid populations on susceptible plants were higher when the plant was adjacent to a resistant plant than when adjacent to another susceptible plant. The effect of resistant plants on aphid movement and distribution could lead to unintended side-effects such as greater spread of plant viruses or altered effectiveness of biological control agents.

Concentrations of carbon dioxide (CO₂) are increasing in the atmosphere, affecting soybean (Glycine max L.) phytohormone signaling and herbivore resistance. Whether the impact of elevated CO₂ on phytohormones and induced defenses is a generalized response within this species is an open question. We examined jasmonic acid (JA) and salicylic acid (SA) under ambient and elevated CO₂ concentrations with and without Japanese beetle (Popilliajaponica Newman) damage and artificial damage across six soybean cultivars (HS93–4118, Pana, IA 3010, Loda, LN97–15076, and Dwight). Elevated CO₂ reduced constitutive levels of JA and related transcripts in some but not all soybean cultivars. In contrast to the variation in JA, constitutive levels of salicylic were increased universally among soybean cultivars grown under elevated CO₂. Variation in hormonal signaling may underpin observed variation in the response of insect herbivores and pathogens to plants grown under elevated CO₂.

The effect of previous infestation (preconditioning) by the whitefly Bemisia tabaci (Gennadius) biotype B on the population fitness of subsequent infestations that fed on three isogenic tomato genotypes (wild-type [Wt], a jasmonic acid [JA] defense-enhanced genotype [35S], and a JA-deficient genotype [spr2]) was examined. We tested the hypotheses that whiteflies fed on preconditioned tomatoes (Solanum lycopersicum L.) would have reduced fitness and that the effect would be mediated via the JA-dependent systemic plant defense pathway. Preconditioning by the whitefly resulted in decreased levels of soluble sugars and free amino acids and increased salicylic acid (SA), total phenolics, and condensed tannins for all three genotypes. The durations of the larval and pupal stages were prolonged in whiteflies fed on the preconditioned plants compared with those that fed on control plants. Furthermore, preconditioning resulted in reduced fecundity and intrinsic rate of increase (r_m) of the whiteflies that subsequently fed on the three tomato genotypes. Whiteflies were more likely to feed and deposit eggs on control plants than on preconditioned plants. Our results indicate that preconditioning induced decreases in leaf nutrients and increased induction of an SA based defense that degraded the quality of the substrate as evidenced by an increased developmental time and reduced fecundity of whiteflies that subsequently fed on them.

Plutella xylostella (L.) is susceptible to both the entomopathogen Bacillus thuringiensis and the predator, Brazilian spined soldier bug [Podisus nigrispinus (Dallas)]. The objective of this study was to measure the interaction between the bacterium B. thuringiensis and the predator P. nigrispinus. We also studied the behavior of P. nigrispinus in relation to its choice between B. thuringiensis-infected and healthy P. xylostellais larvae. In the first treatment, P. nigrispinus nymphs were fed daily with B. thuringiensis-infected P. xylostella larvae and distilled water. In the second treatment, nymphs were fed daily with healthy larvae and a suspension of B. thuringiensis as a source of water. The control nymphs were fed daily with healthy larvae and water. Adult P. nigrispinus were separated by sex, couples were formed, and they were fed daily with P. xylostelL• larvae derived from the treatments. We followed the development of P. nigrispinus and measured its biological characteristics. On the basis of these data, parameters were determined for the construction of life tables. A choice test was used to compare infected and healthy larvae. The HD1 strain of B. thuringiensis does not affect the biological characteristics of P. nigrispinus when fed infected larvae and water or healthy larvae and B. thuringiensis suspension. Our study shows that integrated management of P. xylostella, a pest of the Brassicaceae, is feasible by using the HD1 strain of B. thuringiensis and the predator P. nigrispinus, because the predator shows no preference for infected or healthy P. xylostella larvae.

A crowdsourced dataset of 1,335 honey bee (Apis mellifera L.) swarm events in Germany in 2011 was created by beekeepers, public institutions, and members of the public and analyzed with respect to prevailing weather. The emergence of swarms appeared to be influenced by temperature and rainfall. On successive warm days in May the number of swarming events increased noticeably, but during a mid-month frost event the number of swarming events dropped markedly. Swarming events also occurred only rarely on rainy days. This study showed how crowdsourcing can be used to generate large, useful, phenological datasets.

Understanding the behavioral basis of dispersal and colonization is critical in biological control systems, where success of a natural enemy depends in part on its ability to find and move to new host patches. We studied behavior of the specialist weevil Rhinoncomimus latipes Korotyaev, a biological control agent of mile-a-minute weed, Persicaria perfoliata (L.) H. Gross, by releasing weevils at the forest edge and monitoring their colonization of potted host plants arrayed along the edge, out into the open field, and into the forest. Both distance from the release cage and habitat where plants were located affected colonization, with more than twice as many weevils found on plants at 2 m than at 6 or 14 m; at 14 m, 6–8 times as many weevils colonized plants along the forest edge compared with plants in the open field or within the forest. In a second experiment, weevils that were released in an open field 12 m from the forest edge initially flew in all directions, but again ultimately colonized more plants at the edge than out in the open field. This species may be adapted to seek host plants at the forest edge, because P. perfoliata generally is found in riparian corridors in its native range and along forest edges in North America. Results suggest that R. latipes will move successfully to new P. perfoliata patches along wooded edges, but may not readily locate isolated patches in the open or those embedded in forests.

An animal's body size plays a predominant role in shaping its interspecific interactions, and, in encounters between two predators, often determines which shall be predator and which shall be prey. Spiders are top predators of insects, yet can fall prey to mud-dauber wasps that provision their larval nests with paralyzed spiders. Here we examined predator-prey interactions between Chalybion californicum (Saussure) (Sphecidae), a mud-dauber wasp, and Parasteatoda tepidariorum C. L. Koch (Theridiidae), a cobweb spider. We examined whether a spider's size influences its response to an attacking wasp, and report a size-dependent change in spider behavior: small-sized spiders fled, whereas medium- and large-sized spiders fought in response to wasp attacks. From the wasps' perspective, we examined whether spider size influences a wasp's hunting behavior and capture success. We found that wasps commonly approached small spiders, but were much less likely to approach medium and large spiders. However, wasp capture success did not vary with spider size. We also report a strategy used by Chalybion wasps toward cobweb spiders that is consistent with an interpretation of aggressive mimicry.

Sexual behavior of male moths after prolonged exposure to the 1-ng pheromone/m³ air previously measured in orchards treated with pheromone for mating disruption was examined in a flight tunnel. The exposure of Grapholita molesta (Busck) to 1-ng (Z)-8-dodecen-l-yl acetate (Z8–12:OAc) /m³ air for 15 min had no effect on their ability to fly upwind to a conspecific, virgin calling female. After 30 min of exposure, males exposed to a control treatment were 1.4× more likely orient to a female than males exposed to pheromone-treated air. Some G. molesta males retained the ability to orient to a female after a 30-min exposure period when the aerial concentration of Z8-12:OAc was increased 500,000× to 0.5 gm/m³. Prolonged exposure to Z8–12:OAc did not affect response to a synthetic pheromone lure. The time required to initiate behavioral responses to a female or a lure was not affected by pheromone exposure. Male Choristoneura rosaceana (Harris) exposed to a control treatment for 15 min were 38.5× more likely to orient to a conspecific, virgin calling female than males exposed to 1-ng (Z)-11-tetradecen-1-yl acetate (Z11-14:OAc)/m³ air for 15 min. After 30 min of exposure males were unable to fly upwind to a female. Males exposed to a control treatment for 15 min were 4.3× more likely to fly upwind to a synthetic pheromone lure than males exposed to 1-ng Z11–14:OAc/m³ air for 15 min. The time required to initiate behavioral responses to a female or a lure was not affected by exposure to pheromone.

Western bean cutworm, Striacosta albicosta (Smith), has undergone a recent eastward expansion from the western U.S. Corn Belt to Pennsylvania and parts of Canada. Little is known about its ecology and behavior, particularly during the early instars, on corn (Zea mays L.). There is a narrow treatment window for larvae, and early detection of the pest in the field is essential. An understanding of western bean cutworm larval feeding and early-instar dispersal is essential to understand larval survival and establishment in corn. Studies were conducted in 2009 through 2011 in Nebraska to determine the feeding and dispersal of early-instar western bean cutworm on corn. The treatment design was a factorial with three corn stages (pretassel, tassel, and posttassel) and five corn plant zones (tassel, above ear, primary ear, secondary ear, and below ear) in a randomized complete block design. The effects of different corn tissues on larval survival and development were investigated in laboratory studies in a randomized complete block design during 2009 and 2011. Treatments were different corn tissues (leaf alone, leaf with developing tassel, pollen, pollen plus silk, and silk alone). Results demonstrated that neonate larvae move to the upper part of the plant, independent of corn stage. Larval growth was optimal when fed on tassel tissue. Overall results indicated a selective benefit for movement of the early instar to upper part of the plant.

Cannibalism is a very important factor regulating population dynamics of the red flour beetle. After several days of feeding, the flour becomes conditioned by the beetles, which can affect rates of cannibalism. Flour conditioning is caused by an accumulation of feces, pheromones, and ethylquinone, which is a repellent produced by the beetles. We determined the effect of five different levels of flour conditioning on cannibalism of red flour beetle eggs and pupae by adult and larval stages. Larvae had the highest rates of egg cannibalism (12 eggs eaten over the 4-d period) followed by female adults (seven eggs consumed). Adult males had the lowest rates of cannibalism with only two eggs consumed. Cannibalism of eggs by females was correlated negatively with the level of flour conditioning. There was no effect of flour conditioning on egg or pupal cannibalism by larvae or adult males. Cannibalism by adult females may decrease as the level of flour conditioning increases because females may spend less time tunneling in highly conditioned flour and more time trying to disperse to other areas that are better for oviposition.

Wheat, the most important cereal crop in the Northern Hemisphere, is at-risk for an approximate 10% reduction in worldwide production because of animal pests. The potential economic impact of cereal crop pests has resulted in substantial research efforts into the understanding of pest agroecosystems and development of pest management strategy. Management strategy is informed frequently by models that describe the population dynamics of important crop pests and because of the economic impact of these pests, many models have been developed. Yet, limited effort has ensued to compare and contrast models for their strategic applicability and quality. One of the most damaging pests of wheat in North America is the Russian wheat aphid, Diuraphis noxia (Kurdjumov). Eighteen D. noxia population dynamic models were developed from the literature to describe pest intensity. The strongest models quantified the negative effects of fall and spring precipitation on aphid intensity, and the positive effects associated with alternate food source availability. Population dynamic models were transformed into spatially explicit models and combined to form a spatially explicit, model averaged result. Our findings were used to delineate pest intensity on winter wheat across much of the Great Plains and will help improve D. noxia management strategy.

A 2-yr study was conducted in wheat, Triticum aestivum L., in South Carolina involving weekly sampling of cereal leaf beetle, Oulema melanopus (L.). According to the Spatial Analysis by Distance IndicEs (SADIE) aggregation index, adults (80% of sampling date-field combinations) were more frequently aggregated than eggs (26%) and larvae (57%). Spatial and temporal stability, as indicated by positive association indices among sampling dates, was significant in 27, 30, 33 and 31% of analyses for adults in fields A, B, C, and D, respectively. Peak densities of adults were also spatially associated with peak densities of eggs and larvae in all fields, except for larvae in fields C and D. Spike numbers were greater in interior portions of the field compared with field edges. All stages of O. melanopus were positively associated with spike counts on at least one sampling date, generally corresponding to peak densities of each life stage. This study provides insight into the importance of wheat stand as a potential major factor influencing the spatial distribution of O. melanopus. Determining when and where O. melanopus accumulate in wheat fields in the southeastern United States can provide useful information that could lead to improved sampling plans and more efficient use of insecticides.

Immunoproteins are markers that are useful for monitoring dispersal and/or pest consumption, but current application techniques are less effective for the large guild of piercing-sucking predators important in biocontrol. We quantified the use of protein immunomarks in tracking emigration of spined soldier bug, Podisus maculiventris Say (Hemiptera: Pentatomidae) and predation on the hornworm caterpillar, Manduca sexta L. (Lepidoptera: Sphingidae). An external protein mark was topically applied to adult P. maculiventris to assess persistence under field conditions for >2 wk. Internal marks were incorporated into the artificial diet of M. sexta to test retention of the internal mark in the prey and uptake of the mark by predators. External marks remained detectable in 100% of individuals after 3 d and >50% still tested positive at 12 d after application in the field. Internal diet-based marking was also effective in tracking feeding by P. maculiventris on M. sexta, especially using rabbit IgG that was far more persistent than chicken IgY. Nearly 90% of stink bugs fed caterpillars previously reared on protein-enriched diet retained their mark for 24 h. Surprisingly, diet concentration and time reared on diet had comparatively little impact on mark retention. Development on unmarked tomato leaves clearly diluted the initial diet mark, but plant-reared individuals that were marked were still successfully detected in 35 and 20% of the predators.

Empirical studies using visual search methods to investigate spider communities were conducted with different sampling protocols, including a variety of plot sizes, sampling efforts, and diurnal periods for sampling. We sampled 11 plots ranging in size from 5 by 10 m to 5 by 60 m. In each plot, we computed the total number of species detected every 10 min during 1 hr during the daytime and during the nighttime (0630 hours to 1100 hours, both a.m. and p.m.). We measured the influence of time effort on the measurement of species richness by comparing the curves produced by sample-based rarefaction and species richness estimation (first-order jackknife). We used a general linear model with repeated measures to assess whether the phase of the day during which sampling occurred and the differences in the plot lengths influenced the number of species observed and the number of species estimated. To measure the differences in species composition between the phases of the day, we used a multiresponse permutation procedure and a graphical representation based on nonmetric multidimensional scaling. After 50 min of sampling, we noted a decreased rate of species accumulation and a tendency of the estimated richness curves to reach an asymptote. We did not detect an effect of plot size on the number of species sampled. However, differences in observed species richness and species composition were found between phases of the day. Based on these results, we propose guidelines for visual search for tropical web spiders.

When assessing the species richness of a taxonomic group in a specific area, the choice of sampling method is critical. In this study, the effectiveness of three methods for sampling syrphids (Diptera: Syrphidae) in tropical forests is compared: Malaise trapping, collecting adults with an entomological net, and collecting and rearing immatures. Surveys were made from 2008 to 2011 in six tropical forest sites in Costa Rica. The results revealed significant differences in the composition and richness of syrphid faunas obtained by each method. Collecting immatures was the most successful method based on numbers of species and individuals, whereas Malaise trapping was the least effective. This pattern of sampling effectiveness was independent of syrphid trophic or functional group and annual season. An advantage of collecting immatures over collecting adults is the quality and quantity of associated biological data obtained by the former method. However, complementarity between results of collecting adults and collecting immatures, showed that a combined sampling regime obtained the most complete inventory. Differences between these results and similar studies in more open Mediterranean habitats, suggest that for effective inventory, it is important to consider the effects of environmental characteristics on the catchability of syrphids as much as the costs and benefits of different sampling techniques.

Knowledge of the Colorado potato beetle's, Leptinotarsa decemlineata (Say), relationship to previous potato crops has contributed to the development of a pest management strategy focused upon crop rotation. Previous investigations revealed that potato rotations exceeding 0.4 km were effective in reducing colonization in current season potato. The current study examines the relationship between beetle abundance in potato (Solanum tuberosum L.) and distance from multiple, previous year potato fields in Wisconsin, and integrates information about the influence of natural habitats adjacent to previous season potato. Colorado potato beetle count data were collected in 1998 and 2008 and distance to previous potato, field areas, and landscape classes were estimated using maps from 1997 and 2007. Poisson regression was used to relate counts to combinations of distance and local landscape characteristics calculated for all fields within 1,500 m of sampled potato. In 1998, beetle counts measured in current season potato declined significantly with increasing distance from previous potato fields and field size did not influence these counts. However, there was no relationship between beetle abundance and distance to prior year potatoes in 2008. In both years, increased proportions of surrounding habitats, previously described as preferred for diapause sites (e.g., wooded field boundaries), did not relate significantly to counts. However, grassland habitat was negatively correlated with counts. Results indicate that distance from previous potato remains an important factor to reduce the magnitude of colonization. This analysis further suggests that certain landscape components (e.g., grassland) may influence infestation, which may be useful for refining future integrated pest management programs.

Natural enemies of the invasive pest Aphis glycines Matsumura can prevent its establishment and population growth. However, current A. glycines management practices include the application of broad-spectrum insecticides that affect pests and natural enemies that are present in the field at the time of application. An alternative is the use of selective insecticides that affect the targeted pest species, although having a reduced impact on the natural enemies. We tested the effects of esfenvalerate, spirotetramat, imidacloprid, and a combination of spirotetramat and imidacloprid on the natural enemies in soybean during the 2009 and 2010 field season. The natural enemy community that was tested differed significantly between 2009 and 2010 (F = 87.41; df = 1, 598; P < 0.0001). The most abundant natural enemy in 2009 was Harmonia axyridis (Pallas) (56.0%) and in 2010 was Orius insidiosus (Say) (41.0%). During 2009, the abundance of natural enemies did not vary between the broad-spectrum and selective insecticides; however, the abundance of natural enemies was reduced by all insecticide treatments when compared with the untreated control. In 2010, the selective insecticide imidacloprid had more natural enemies than the broad-spectrum insecticide. Although we did not observe a difference in the abundance of the total natural enemy community in 2009, we did observe more H. axyridis in plots treated with spirotetramat. In 2010, we observed more O. insidiosus in plots treated with imidacloprid. We suggest a couple of mechanisms to explain how the varying insecticides have different impacts on separate components of the natural enemy community.

In an attempt to improve semiochemical-based treatments for protecting forest stands from bark beetle attack, we compared push—pull versus push-only tactics for protecting lodgepole pine (Pinus contorta Douglas ex Loudon) and whitebark pine (Pinus albicaulis Engelm.) stands from attack by mountain pine beetle (Dendroctonus ponderosae Hopkins) in two studies. The first was conducted on replicated 4.04-ha plots in lodgepole pine stands (California, 2008) and the second on 0.81-ha plots in whitebark pine stands (Washington, 2010). In both studies, D. ponderosae population levels were moderate to severe. The treatments were 1) push-only (D. ponderosae antiaggregant semiochemicals alone); 2) push—pull (D. ponderosae antiaggregants plus perimeter traps placed at regular intervals, baited with four-component D. ponderosae aggregation pheromone); and 3) untreated controls. We installed monitoring traps baited with two-component D. ponderosae lures inside each plot to assess effect of treatments on beetle flight. In California, fewer beetles were collected in push—pull treated plots than in control plots, but push-only did not have a significant effect on trap catch. Both treatments significantly reduced the rate of mass and strip attacks by D. ponderosae, but the difference in attack rates between push—pull and push-only was not significant. In Washington, both push—pull and push-only treatments significantly reduced numbers of beetles caught in traps. Differences between attack rates in treated and control plots in Washington were not significant, but the push-only treatment reduced attack rates by 30% compared with both the control and push—pull treatment. We conclude that, at these spatial scales and beetle densities, push-only may be preferable for mitigating D. ponderosae attack because it is much less expensive, simpler, and adding trap-out does not appear to improve efficacy.

In recent years, several attractant pheromones have been identified for cerambycid beetles, including 2-(undecyloxy)-ethanol (hereafter monochamol) for Monochamus galloprovincialis (Olivier), M. alternatus Hope, and M. scutellatus (Say). This study screened eight known cerambycid pheromones or their analogues (including monochamol) as potential attractants for M. carolinensis Olivier and M. titillator (F.), in the presence and absence of the host volatile α-pinene. Monochamol attracted M. carolinensis in the presence and absence of α-pinene, whereas M. titillator was only attracted to the combination of monochamol and α-pinene. (2R*,3R*)-2,3-Hexanediol also attracted both M. carolinensis and M. titillator, but only in the presence of α-pinene. Subsequent coupled gas chromatography—mass spectrometry and gas chromatography—electroantennogram detection analyses of extracts of volatiles collected from both sexes demonstrated that male M. carolinensis and M. titillator release monochamol, and that antennae of males and females of both species detect it. These results indicate that monochamol is a male-produced pheromone for both M. carolinensis and M. titillator.

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is an exotic wood-boring insect that vectors the mycopathogen responsible for laurel wilt, a lethal vascular disease of trees in the Lauraceae, including avocado (Persea americana Mill.). Effective semiochemical-based detection and control programs for X. glabratus will require an understanding of the chemical ecology and host-seeking behaviors of this new invasive pest. This study 1) presents an electroantennography (EAG) method developed for assessment of olfactory responses in ambrosia beetles; 2) uses that new method to quantify EAG responses of X. glabratus, X. affinis, and X. ferrugineus to volatiles from three host-based attractants: manuka oil (essential oil extract from Leptospermum scoparium Forst. & Forst.), phoebe oil (extract from Phoebe porosa Mex.), and wood from silkbay (Persea humilis Nash); and 3) documents temporal differences in host-seeking flight of the sympatric Xyleborus species. Field observations revealed that X. glabratus engages in flight several hours earlier than X. affinis and X. ferrugineus, providing a window for selective capture of the target pest species. In EAG analyses with X. glabratus, antennal response to phoebe oil was equivalent to response to host Persea wood, but EAG response elicited with manuka oil was significantly less. In comparative studies, EAG response of X. glabratus was significantly higher than response of either X. affinis or X. ferrugineus to all three host-based substrates. Future research will use this EAG method to measure olfactory responses to synthetic terpenoids, facilitating identification of the specific kairomones used by X. glabratus for host location.

With widespread planting of Bt cotton and an associated reduction in the use of broad-spectrum insecticides, the mirid bugs Apolygus lucorum (Meyer-Dür) and Adelphocoris suturalis Jakovlev (Hemiptera: Miridae) become major pests of cotton in northern China in recent years. Both species overwinter as diapausing eggs that may enhance ability to survive the cold winter. The effects of photoperiod and temperature on diapause induction in A. lucorum and A. suturalis were investigated under laboratory conditions. Egg diapause was induced primarily by short photoperiod. Temperatures ranging between 17 and 26°C had little effect on diapause induction for both species. The impact of photoperiod (x) on diapause incidence (y) was described with modified Michaelis—Menten models y = 1.1(14 - x)/(14.82 - x) for A. lucorum and y = 1.07(14 - x)/(14.79 - x) for A. suturalis. The critical photoperiod for diapause induction in the first instars of parental A. lucorum and A. suturalis calculated from the models above was almost identical, at 13.3 h (13 h, 18 min) in a 24-h cycle. The parental nymphal stage was sensitive to short photoperiod for diapause induction in both species, with the first-instar nymphs the most sensitive. The sensitivity to short photoperiod decreased gradually as the A. suturalis nymphs developed, whereas the sensitivity dropped sharply at the second instar of A. lucorum. The adults of both species exhibited little sensitivity to photoperiod for diapause induction.

Many insects survive cold winter temperatures by entering into a transient, dormant state. Social wasp queens in the genus Vespula undergo such a state of physiological dormancy known as diapause to survive winter conditions. We experimentally investigated the effects of size, shape, genotype, and matedness on the overwintering survival of Vespula maculifrons Buysson (Hymenoptera: Vespidae) queens in two study years. Queens first were mated in the laboratory and then subjected to overwintering conditions. The sizes of several morphological traits of each queen were measured, and the genotype of each queen was determined at polymorphic microsatellite loci allowing queens to be assigned to distinct patrilines. We found that overall large body size resulted in high overwintering survival for queens in one study year. In addition, queen thinness was positively and significantly associated with overwintering survival in both years. In contrast, we found no evidence for an effect of patriline on overwintering survival, which is consistent with the idea that natural selection removes genetic variation associated with traits directly linked to fitness. We also found no effect of queen matedness on overwintering survival, as expected under models suggesting that mating should not adversely affect female viability in social hymenopteran insects. Overall, our study demonstrates that some aspects of body size and shape are significantly associated with overwintering survival in V. maculifrons queens. However, variation in survival arising from genotypic differences or mating effects is limited due, in part, to the way selection operates in social insect species.

The influence of simulated climate change on body weight and depletion of fat body reserves was studied during diapause in the European solitary bee Osmia rufa L. (Hymenoptera: Megachilidae). Insects (females) were reared and collected from outdoor nests from September to March. One cohort of females was weighed and dissected immediately for analyses, whereas another cohort was subjected to simulated warmer temperature (15°C for 7 d) before analyses. A gradual decline in body mass and fat body content was recorded with declining temperatures from September to January in female bees from natural conditions. Temperature increased gradually from January to March with a further decline in body mass and fat body content. The fat body development index dropped from five in September—October (≈89% individuals) to four for the period from November to February (≈84% individuals) and further to three in March (95% individuals) before emergence. Simulated warmer winter temperature also resulted in a similar decline in body weight and fat body content; however, body weight and fat body content declined faster. The fat body development index dropped to three in December in the majority of individuals and continued at this level until March just before emergence. Taken together, our data indicate an earlier depletion of fat body reserves under simulated climate change conditions that may impact ovarian development and reproductive fitness in O. rufa.

Temperature affects all levels of biological organization and multiple aspects of ecological performance and fitness. Descriptions of thermal biology are, therefore, essential pieces of information for studying ecology in varying thermal environments. This paper describes the thermal biology of the spider Rabidosa rabida by using three common descriptive measures. Spiders were collected from two populations on mountains in Arkansas that share similar climate and vegetation. Maximum sprint speed across temperature was used to calculate an estimate of thermal sensitivity of locomotor ability. Spiders were placed in a thermal gradient to determine thermal preference. Spiders' body temperatures were increased or decreased until the ability to move was lost. Results were compared between the populations to describe intraspecific variation. Maximum sprint speed increased across temperatures showing moderate sensitivity (Q_{10 all spiders} = between 1.74 and 2) except at the highest temperatures in males, and the lowest temperatures in both sexes. Maximum sprint speeds differed between populations (P < 0.05). The critical thermal maximum was shown to be 42.9°C ± 0.70. The critical thermal minimum was estimated at 0°C. Thermal preference of R. rabida was determined to be 31.9°C ± 0.44 showing no significant variation between populations. This study provides a first description of thermal biology in an ecologically important spider, and shows evidence of variation between thermal biology measures between populations with similar climate but no gene flow. Having adapted to various and changing conditions in the past, this spider and others like it can provide many ecologically and evolutionarily interesting lines of inquiry.

The cabbage aphid Brevicoryne brassicae (L.) (Hemiptera: Aphididae), one of the most important pests of cruciferous crops, overwinters as nymph and adult on winter cabbages in Tehran, Iran, and forms large populations on these plants during winter. To determine the cold hardiness of this aphid, adults and first-instar nymphs were collected monthly from ornamental cabbages planted in the field from October of 2009 to May of 2010. Supercooling points and LT₅₀ values (the temperature at which 50% of population died after 24-h exposure to subzero temperatures) were investigated. To elucidate the relation between cold hardiness and cryoprotectants, sugars and polyols were determined by high performance liquid chromatography. Changes of mean supercooling point were small during sampling dates. LT₅₀ values of adults decreased gradually from -6.9°C in October to -12.2°C in January, showing the increase in cold hardiness during cold seasons. Moreover, nymphs showed similar trends in LT₅₀ values. Glucose, mannitol, myo-inositol, and trehalose were identified in overwintering aphids. Total amount of the cryoprotectants increased to the highest (72.8 ± 9.2 µmol/g fresh weight) in January. There was a significant correlation between LT₅₀ values and the cryoprotectant contents, suggesting their important role in aphid cold hardiness. Results have shown that B. brassicae is sufficiently cold tolerant to survive mild winter temperatures and is able to form large populations on winter cabbages, causing it to be considered a threat to early season crops, especially oilseed rape.

Climate change will result in warmer temperatures and an increase in the frequency and severity of extreme weather events. Given that higher temperatures increase the reproductive rate of temperate zone insects, insect population growth rates are predicted to increase in the temperate zone in response to climate. This consensus, however, rests on the assumption that food is freely available. However, under conditions of limited food, the reproductive output of the Texan cricket Gryllus texensis (Cade and Otte) was highest at its current normal average temperature and declined with increasing temperature. Moreover, low food availability decreased survival during a simulated heat wave. Therefore, the effects of climate change on this species, and possibly on many others, are likely to hinge on food availability. Extrapolation from our data suggests that G. texensis will show larger yearly fluctuations in population size as climate change continues, and this will also have ecological repercussions. Only those temperate zone insects with a ready supply of food (e.g., agricultural pests) are likely to experience the predicted increase in population growth in response to climate change; food-limited species are likely to experience a population decline.

Laboratory studies were conducted to determine the effects of constant temperatures (7, 22, and 30°C) and corresponding fluctuating temperatures (0–14, 15–29, and 23–37°C) on the development of diamondback moth, Plutella xylostella (L.), and its North American parasitoid Diadegma insulare (Hellén). Parasitized third-instar diamondback moth larvae were reared until adult mortality in individual thermal gradient cells at different temperature regimes. Larval mortality, parasitism success, pupal mortality, larval and pupal developmental time, adult longevity, and pupal and adult dry weight were recorded. Overall diamondback moth larval mortality was low. The pupal mortality of D. insulare increased with increasing temperature; however, diamondback moth did not show such a response. Greatest parasitism success (67%) was found at constant and fluctuating 22°C and fluctuating 7°C, and the lowest (30%) at fluctuating 30°C. Longer development times and greater pupal body masses occurred at lower temperatures for both insects. Significant differences occurred between constant and fluctuating temperature regimes for most parameters of both insects. Fluctuating compared with constant temperatures caused shorter development times, similar body mass, and higher adult longevity for both insects at optimal and lower temperature ranges. Both insects experienced 0°C at fluctuating 7°C (0–14°C) and survived. These results have important implications for extrapolating temperature effects on insects in laboratory studies with constant temperatures. Comparing successful parasitism capacity of the wasp and pupal survival and body mass of both host and parasitoid, we conclude that D. insulare is a more effective parasitoid at lower temperatures.

Three sequential studies were conducted on the interacting effects of exposure to low (5°C) temperature for 0, 7, 28, 56, or 84 d followed by incubation at 10, 15, or 20^°C on the egg diapause of Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae). This beetle was imported from China as a potential biological control agent for hemlock woolly adelgid, Adelges tsugae (Annand) (Hemiptera: Adelgidae). Very few eggs laid and held at a constant 15 or 20°C showed any indication of development. Only eggs exposed to temperature combinations of 5 and 10°C had >50% hatch. Highest percent hatch and fastest development occurred when eggs were held at 5°C for 56 or 84 d followed by holding at 10°C. A model estimated the lower threshold for postdiapause development to be 2°C. The effect of temperature on egg hatch was similar at photoperiods of 12:12 and 16:8 (L:D) h, suggesting egg development is not governed by photoperiod or light exposure. Collectively these data indicate that S. camptodromus eggs laid in the spring and summer go through an aestivo-hibernal diapause that is maintained by warm temperatures and that development resumes when temperatures drop, in parallel with the development of hemlock woolly adelgid. This concurrent development allows S. camptodromus eggs to hatch while hemlock woolly adelgid is laying eggs. This synchrony between the development of S. camptodromus eggs and the overwintering adelgid suggest this beetle may be a good candidate for the biological control of the hemlock woolly adelgid.

Much attention has been focused on insects' ability to survive long-term high-temperature stress and on their resulting population distributions under global warming. In this study, life tables of the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype B, were collected over five consecutive generations at 27, 31, and 35°C and for one generation at 37°C. At 37°C, the intrinsic rate of increase (r) and the net reproductive rate (R₀) of the whitefly were 0.0383 d^-1 and 2.8 offspring, respectively. These results demonstrate that the lethal high temperature for B. tabaci is >37°C. At 27°C, neither R₀ nor r decreased over the generations studied. However, both of these values decreased over time at 31 and 35°C, and the decrease was more evident at 35°C. Our results on the ability of B. tabaci biotype B to survive long-term high-temperature stress are important for understanding its population distribution under global warming.

Social insects are among the world's most successful species at invading new environments. Their characteristic division of labor can influence their capacity to colonize new habitats, often with negative ecological or economic impact. The social Hymenoptera (i.e., ants, bees, and wasps), are well studied in this regard, but much less is known about the invasive biology of termites (Isoptera). In this study we use province-wide sampling and a population genetic analysis to infer the minimum number of eastern subterranean termite [Reticulitermes flavipes (Kollar) ] introductions into Ontario (Canada). Structure analysis of multilocus microsatellite genotypes grouped the 30 collection points into K = 3 genetic clusters, suggesting as many three independent introductions into southern Ontario. Levels of genetic diversity were higher in termites from the Pelee region than in termites from Toronto and other Ontario cities, suggesting that these Pelee termite populations are potentially older and native to Ontario. A single origin scenario, in which all populations stem from a single source, therefore is not supported by the genetic data. Instead, our analysis suggests multiple independent introductions of this highly social, subterranean termite into Ontario, where the species is now well established as a structural pest of urban habitats.

Early-tier studies are the initial step in the environmental risk assessment of genetically engineered plants on nontarget arthropods. They are conducted in the laboratory where surrogate species are exposed to higher concentrations of the arthropod-active compound than those expected to occur in the field. Thus, early-tier tests provide robust data and allow to make general conclusions about the susceptibility of the surrogate to the test substance. We have developed an early-tier test for assessing the toxicity of orally-active insecticidal compounds to larvae of the ladybird beetle Coccinella septempunctata L. (Coleoptera: Coccinellidae). Using potassium arsenate and the protease inhibitor E-64 as model compounds, we validated the bioassay set-up for C. septempunctata. Sucrose solution containing the test compound was offered to larvae for 24 h on the first day of each of its four larval instars. Subsequently, larvae were fed ad libitum with Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs. Both compounds negatively affected C. septempunctata larval survival and development, and adult weight, indicating that the bioassay setup was able to detect dietary effects of insecticidal substances on the ladybird. Power analyses revealed that sample sizes of 20 or 45 per treatment are sufficient to detect 50 or 20% differences between the control and treatment groups, respectively, for the various measurement endpoints.