Cereal leaf beetles (CLBs), a group of chrysomelid beetles of the genus Oulema (Coleoptera: Chrysomelidae), are well-known pest insects of small-grain cereals in many countries of the Northern hemisphere. Due to the small differences in morphology of species within this genus, classification up to species level remains a challenging task. Since an accurate view of species composition is important for developing targeted control strategies, the goal of this study was to unravel the Oulema species composition in Flanders' wheat fields. During three subsequent years at a series of different fields, Oulema species were collected and classified up to species level (2016: 28 fields, 2017: 30 fields, and 2018: 23 fields). This study reveals that the population consists of four different species: Oulema melanopus, Oulema duftschmidi, and Oulema obscura were most frequently encountered, while Oulema rufocyanea was only marginally present. Furthermore, the population was highly dynamic, as the population share of each species varied between different growing seasons and between the various sampling events within each season. The distance from the field edge had a minor influence on the species composition, but the abundance of beetles increased with the distance to the field edge. A discriminant analysis revealed that based on the measurements of various body parts, an accurate classification up to species level is possible. In conclusion, we observed that the population densities fluctuated within and between years, resulting in variable incidence of CLB in winter wheat fields in the Flanders region.

Simulium damnosum (Theobald) sensu lato (s.l.) is a complex of many species of black flies that transmit Onchocerca volvulus (Leuckart) to varying capacities based on their ecological zones in Africa. The presence of three ecological zones in Osun, an onchocerciasis endemic state in Nigeria, is the basis of this study that is aimed at determining the population dynamics of S. damnosum s.l. in the state. Adult S. damnosum s.l. were collected fortnightly in the wet and dry seasons for 2 yr between October 2014 and September 2016 in the Guinea savanna (Iwo), derived savannah (Ede), and rainforest (Obokun) zones. Temperature, relative humidity, and rainfall of the study area were measured. The results showed that in the first year, Ede had 62.8% of the total black fly population while Obokun had the lowest (1.5%). In the second year, Iwo had 94.1% of the total black fly population while Obokun had the least population.The black fly population was significantly higher during the wet season than dry season in Iwo and Ede, but was not significant in Obokun. The results further showed that black fly populations were strongly correlated with ambient temperature and rainfall in Iwo, whereas no relationships were recorded for Ede and Obokun. The results suggest that abundance of black flies during the wet season was due to increased rainfall which in turn created rapids and conditions suitable for development of preimaginal stages into adults.These vector surveillance findings will guide control decisions necessary for endemic communities to meet elimination targets.

Overgrazing by large mammalian herbivores has led to significant adverse impacts on ecosystems globally. Insects are often a key taxon affected by large herbivores because the plants that are grazed provide crucial food and habitat. By changing vegetation, overgrazing by herbivores could affect aspects of insect morphology, including through changes to larval development due to reduced food availability, and adult dispersal ability due to habitat fragmentation. We investigated the wing morphology of moth species in two contrasting sites at Lake Toya in Hokkaido, Japan. We compared moths on Nakajima Island where deer are overabundant, with moths from the lakeshore 3 km away where deer are far less abundant. We compared forewing size and aspect ratio (length/width) of 13 moth species from both lakeshore and island sites. Four species, three of which were herb-feeding generalists, had significantly smaller wings on the island compared with the lakeshore. Seven species demonstrated a reduction in wing aspect ratio, whereas one species, the largest we measured, showed an increase in wing aspect ratio. We suggest that these morphological changes could be induced by overgrazing by deer (i.e., a reduction in moth host plant biomass and quality) and/or the isolation of moth populations on Nakajima Island. Further work is needed to reveal how these confounded but potentially interacting effects contribute to the morphological changes we found in the moths on the island. Our results show that habitat isolation and overabundance of deer populations can affect moth wing morphology, with potential implications for their population dynamics and community structure.

Arthropods are key components of grassland ecosystems. Though arthropod communities are often strongly influenced by plant communities, plants and arthropods may respond differently to disturbance. Studying plant responses alone may, therefore, not fully capture altered ecosystem dynamics; thus multi-trophic approaches are critical to fully understand ecosystem responses to disturbance. Energy development is a large-scale driver of disturbance in northern Great Plains rangelands, and recovery of arthropod communities following reclamation is not well understood. We sampled Orthoptera and spiders in western North Dakota, United States, in 2016. Samples were collected from 14 reclaimed oil well sites (‘reclaims’) 2–33 yr since reclamation, and native prairie at two distances (50 and 150 m) from reclaim edges. Overall Orthopteran and spider abundances on reclaims and native prairie did not differ; however, Orthopteran community composition and species abundances were distinct on reclaims versus native prairie, including increased abundances of Melanoplus femurrubrum (De Geer) (Orthoptera: Acrididae) (a noted crop pest) on reclaims. In contrast, NMS analyses revealed no differences in spider community composition between reclaims and native prairie, although abundances of one group (Salticidae) strongly decreased on reclaims. We present one of the first studies to investigate impacts of energy development and reclamation on arthropod communities. While reclamation efforts successfully recovered abundances and biomass of arthropod herbivores and predators, Orthopteran (but not spider) community composition on reclaims has not recovered to match that of intact prairie even 30 yr after reclamation.These findings suggest that energy development may have long-term or potentially irreversible impacts to rangeland arthropod communities.

By the end of 2017, kudzu bug was reported in 652 counties in the United States since it was first observed in Georgia in 2009. Modeling its invasion dynamics is valuable to guide management through early detection and prevention of further invasion. Herein, we initially estimated the spread rate of kudzu bug with county-level invasion records and then determined important spatial factors affecting its spread during years 2010–2016. As kudzu bug infests a large heterogeneous area and shows asymmetric spread, we first utilized spatially constrained clustering (SCC), an unsupervised machine learning method, to divide the infested area into eight spatially contiguous and environmentally homogenous neighborhoods. We then used distance regression and boundary displacement methods to estimate the spread rates in all neighborhoods. Finally, we applied multiple regression to determine spatial factors influencing the spread of kudzu bug. The average spread rate reached 76 km/yr by boundary displacement method; however, the rate varied largely among eight neighborhoods (45–144 km/yr). In the southern region of the infested area, host plant density and wind speed were positively associated with the spread rate, whereas mean annual temperature, precipitation in the fall, and elevation had inverse relationships. In the northern region, January minimum temperature, wind speed, and human population density showed positive relationships. This study increases the knowledge on the spread dynamics of kudzu bug. Our research highlights the utility of SCC to determine natural clustering in a large heterogeneous region for better modeling of local spread patterns and determining important factors affecting the invasions.

Planthoppers (Nilaparvata lugens, Sogatella furcifera, and Laodelphax striatellus) (Hemiptera: Delphacidae) are the most important pests affecting rice production. Pesticide spraying for its control may cause harmful effects on human health and the environment, especially the loss of biodiversity. The consequences of these changes on biodiversity and ecological services are well studied in tropical irrigated paddy fields, but are largely unknown in subtropical areas. Organic regime provides an environment-friendly method for biodiversity conservation; however, it is unclear whether this regime can suppress planthopper populations effectively in paddy fields. Consequently, we compared species richness, abundance, community structure, and evenness of natural enemies and planthoppers between organic and conventional rice fields (n = 35) distributed across four sites in China. The results showed that species richness was higher in organic fields than in conventional fields. Shannon index and evenness of predators and parasitoids were higher in most of the organic fields than their conventional counterparts. Furthermore, planthopper density showed a significant negative relationship with increased richness and evenness for both predators and parasitoids.These results underscore the notion that management regimes influence biodiversity in rice field. Most importantly, this has direct implications on the efficacy of natural pest control services rendered by predators and parasitoids associated with planthoppers in China and potentially other rice production regions in Asia.

Aphids (Hemiptera: Aphididae) have provided a suitable model to study endosymbionts, their community, and dynamics since the discovery of the obligate endosymbiont Buchnera aphidicola in these organisms. In previous studies, Wolbachia was found in some aphid species. In the present study, we report the prevalence of Wolbachia in aphids sampled from a geographically isolated region (Azores Islands), aiming at a better understanding and characterization of the two newly reported supergroups, M and N. The description of the supergroup M was based on 16S rRNA as well as some protein-coding genes. However, the assignment of the supergroup N was according to 16S rRNA gene sequences of a very few samples. We collected aphid samples and performed phylogenetic analysis of 16S rRNA gene as well as four protein-coding genes (gatB, ftsZ, coxA, and hcpA). The results demonstrate that the 16S rRNA gene data can unambiguously assign the strain supergroup and that the two supergroups, N and M, are equally prevalent in Azorean aphids. The available sequence data for the protein-coding markers can identify supergroup M but the status of supergroup N is inconclusive, requiring further studies. The data suggest that horizontal transmission of Wolbachia (Hertig and Wolbach) between two phylogenetically distant aphid species cohabiting the same plant host.

Under winter and early spring greenhouse growing conditions, suppression of thrips by predatory mites can vary considerably on a species basis. For certain mite species, shorter photoperiods, cooler temperatures, and lower vapor pressures translate to reductions in predation, oviposition, and survival. Therefore, predator species need to be assessed simultaneously to identify those most suitable for use under short-season conditions. In this study, laboratory trials were first conducted to compare rates of Frankliniella occidentalis (Pergande) thrips predation, and oviposition by the phytoseiid predator Transeius montdorensis (Schicha) under simulated summer and winter conditions. Transeius montdorensis consumed similar numbers of first instar thrips, and laid a similar number of eggs under both conditions. In short-season greenhouse cage trials, crop establishment and predatory capacity of T. montdorensis were compared to those for three other predatory mites: Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae), Amblydromalus limonicus (Garman & McGregor) (Acari: Phytoseiidae) and Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae). Over 4–5-wk trials performed in early spring in 2014 and 2016, the number of T. montdorensis mites on pepper plants was either equal or greater to levels in other treatments. In T. montdorensis cages, high levels of thrips suppression were observed, equal to those achieved by A. swirskii or A. limonicus treatments in the 2016 trial, and superior to those by N. cucumeris in both trial years. These findings show that T. montdorensis is a good thrips predator, and provides rationale for the development of this species as a new agent for greenhouse pest management in an expanded temperate area of the world.

Sunn hemp, Crotalaria juncea L., is a warm-season legume that can be planted in rotation to cash crops to add nitrogen and organic matter to the soils, for weed growth prevention, and to suppress nematode populations. Sunn hemp flowers also provide nectar and pollen for pollinators and enhance biological control by furnishing habitat for natural enemies. Experiments were conducted in Northern and North Central Florida to evaluate bee populations that visited flowers within mixed plots of sunn hemp and sorghum-sudangrass and plots of two sunn hemp germplasm lines. Collections of bees that visited ‘AU Golden’ and Tillage Sunn flowers indicated that Xylocopa virginica (L.) (Hymenoptera: Apidae), Xylocopa micans Lepeletier (Hymenoptera: Apidae), Megachile sculpturalis Smith (Hymenoptera: Megachilidae), Megachile mendica (Cresson) (Hymenoptera: Megachilidae), and Megachile georgica Cresson (Hymenoptera: Megachilidae) were present in large numbers in May through July and then again in October. AlthoughTillage Sunn seeds planted in March flowered in May, percent bloom and number of bee visits were low. Compared with short day sunn hemp cultivars, ‘AU Golden’ plants produced flowers early in the season to provide food and habitat for pollinators and have the potential to produce an abundant seed crop in Northern and North Central Florida.

Worldwide studies have used the technique of pollen trapping, collecting pollen loads from returning honey bee (Apis mellifera L.) (Hymenoptera: Apidae) foragers, to evaluate the exposure of honey bees to pesticides through pollen and as a biomonitoring tool. Typically, these surveys have found frequent contamination of pollen with multiple pesticides, with most of the estimated risk of acute oral toxicity to honey bees coming from insecticides. In our survey of pesticides in trapped pollen from three commercial ornamental plant nurseries in Connecticut, we found most samples within the range of acute toxicity in a previous state pollen survey, but a few samples at one nursery with unusually high acute oral toxicity. Using visual sorting by color of the pollen pellets collected in two samples from this nursery, followed by pesticide analysis of the sorted pollen and palynology to identify the plant sources of the pollen with the greatest acute toxicity of pesticide residues, we were able to associate pollen from the plant genus Spiraea L. (Rosales: Rosaceae) with extraordinarily high concentrations of thiamethoxam and clothianidin, and also with high concentrations of acephate and its metabolite methamidophos. This study is the first to trace highly toxic pollen collected by honey bees to a single plant genus. This method of tracking high toxicity pollen samples back to potential source plants could identify additional high-risk combinations of pesticide application methods and timing, movement into pollen, and attractiveness to bees that would be difficult to identify through modeling each of the contributing factors.

Sophonia orientalis (Matsumura), also known as the two-spotted leafhopper, is a widespread exotic pest of many economically important crop plants and ornamental plants in Hawaii. Sophonia orientalis is highly polyphagous and is a major threat to some of the native endemic plants. Despite the successful establishment in Hawaii, interactions of S. orientalis with its host plants remain poorly understood. Previous studies primarily focused on distribution, parasitism, and oviposition of S. orientalis in Hawaii, whereas plant physiological responses to the leafhopper's injury, and, specifically, gas exchange rates in plants, have not yet been described. In this study, we examined a short-term physiological response of a native Hawaiian plant, Hibiscus arnottianus (A. Gray), to injury by S. orientalis. We also explored whether Camellia sinensis (L.) Kuntze, a native host plant of S. orientalis in Asia, exhibits a similar response. We found that H. arnottianus plants demonstrated a rapid (2-d) physiological response to injury accompanied by 40% reduction in rate of photosynthesis and 42% reduction in rate of transpiration, whereas C. sinensis did not exhibit any reduction in gas exchange rates. We did not record any changes in plant chlorophyll levels after plant injury in either species. Our results suggest that H. arnottianus is responding to the leafhopper feeding with a generalized wound response predicted for novel plant–insect herbivore associations. We discuss potential future directions for studies which might focus on host plant responses to S. orientalis in its native versus introduced range.

Most plants form mutualistic associations with arbuscular mycorrhizal (AM) fungi that are ubiquitous in soils. Through this symbiosis, plants can withstand abiotic and biotic stresses. The underlying molecular mechanisms involved in mediating mycorrhiza-induced resistance against insects needs further research, and this is particularly true for potato (Solanum tuberosum L. (Solanales: Solanaceae)), which is the fourth most important crop worldwide. In this study, the tripartite interaction between potato, the AM fungus Rhizophagus irregularis (Glomerales: Glomeraceae), and cabbage looper (Trichoplusia ni Hübner) (Lepidoptera: Noctuidae) was examined to determine whether potato exhibits mycorrhiza-induced resistance against this insect. Plant growth, insect fitness, AM fungal colonization of roots, and transcript levels of defense-related genes were measured in shoots and roots after 5 and 8 d of herbivory on mycorrhizal and nonmycorrhizal plants. AM fungal colonization of roots did not have an effect on potato growth, but root colonization levels increased by herbivory. Larval weight gain was reduced after 8 d of feeding on mycorrhizal plants compared with nonmycorrhizal plants. Systemic upregulation of Allene Oxide Synthase 1 (AOS1), 12-Oxo-Phytodienoate Reductase 3 (OPR3) (jasmonic acid pathway), Protease Inhibitor Type I (PI-I) (anti-herbivore defense), and Phenylalanine Ammonia Lyase (PAL) transcripts (phenylpropanoid pathway) was found during the tripartite interaction. Together, these findings suggest that potato may exhibit mycorrhiza-induced resistance to cabbage looper by priming anti-herbivore defenses aboveground. This study illustrates how mycorrhizal potato responds to herbivory by a generalist-chewing insect and serves as the basis for future studies involving tripartite interactions with other pests.

Specialized interactions between insects and the plants that they consume are one of the most ubiquitous and consequential ecological associations on the plant. Decades of investigation suggest that a narrow diet favors an individual phytophagous insect's performance relative to a dietary generalist. However, this body of research has tended to approach questions of diet breadth and host usage from the perspective of temperate plant–insect associations. Relationships between diet breadth, host usage, and variation in tropical insect preference and performance remain largely uninvestigated. Here we characterize how variation in diet breadth and host usage affect oviposition preference, development, survival, and gain in mass of a Neotropical tortoise beetle Chelymorpha alternans Boheman 1854 (Coleoptera: Chrysomelidae), using a split-brood, sibling experimental design. Host performance was measured after splitting broods among four no-choice host diets. Groups consuming single hosts varied among themselves in developmental time and survival from larva to adult. Performance did not vary among groups consuming multiple and single hosts. Oviposition preference was measured in choice and no-choice tests. Females displayed preference for the original host in both experiments. Developmental time and survival of offspring sourced from the no-choice experiment was measured for two complete generations to explore correlations with female oviposition preference. Preference for the original host correlated with high survivorship and an intermediate developmental time. Survivorship and time to develop were also high on an alternative host that was less preferred. Departures from predictions of prevailing preference–performance hypotheses suggest that host usage presents C. alternans with fitness trade-offs.

Soil meso- and microfauna (<2 mm in size) play an important role in the decomposition and nutrient release of litter. However, most research has focused on the influences of soil fauna on decomposition rates, while the impact of soil fauna on nutrient release has not been fully understood. We evaluated the influence of soil meso- and microfauna communities on nutrient release from decomposing Tilia amurensis Rupr. (Malvales:Tiliaceae) and Acer mono Maxim. (Sapindales:Aceraceae) leaves from the coniferous and broadleaved mixed forests of the Changbai Mountains. Litter decomposition and nutrient release were assessed using litterbags placed at the surface of the litter and using designs both with and without 2-mm mesh to either permit or exclude soil meso- and microfauna. The soil meso- and microfauna increased the decomposition of T. amurensis (not significantly) and A. mono (significantly, by 15%) litters. Presence of the soil meso- and microfauna accelerated the release rate of Mn in the A. mono litter by 59%, whereas it significantly decreased the release rates of Ca (in the T. amurensis litter) and P (in the A. mono litter) by 28 and 48%, respectively.These results suggest that a stronger understanding of the influence of soil fauna on nutrient cycling is necessary to understand the mechanisms of matter circulation.

The outcomes of interspecific interactions between parasitoids depend on a variety of factors. Understanding the influence of these factors is important for classical biological control, where the success of parasitoid releases partly depends on interactions with native and other introduced species. However, results from laboratory experiments may not always reflect those in the field, as densities may be artificially inflated. To mitigate this problem, we examined the effects of multiple densities on interspecific competition between two larval parasitoids of emerald ash borer (Agrilus planipennis Fairmaire): Spathius galinae Belokobylskij and Tetrastichus planipennisi Yang. Parasitoid species were housed individually or together at two different densities, and we measured the effects on percent parasitism and progeny production, before calculating the interaction strengths. We found no significant effects of parasitoid density on percent parasitism, but the effect of competition on parasitism generally was reduced at lower densities. However, there were significant differences in parasitism by species, with S. galinae parasitizing more larvae than T. planipennisi. There were also no significant effects of parasitoid density on the number of progeny produced by each species, though the effect of competition on progeny production was greater at higher densities. Similarly, though, there were significant differences between species in the number of progeny produced. Specifically, T. planipennisi consistently produced larger broods than S. galinae. Our findings complement existing research suggesting that competition between these two species in the field will likely be negligible.

The scale insect, Ericerus pela Chavannes, shows a typical sexual dimorphism. Males and females are different not only in morphology, but also in their ability to secrete wax and ecological adaptability. Here we report the morphological and structural characteristics of wax glands on E. pela females and males. The differences in wax glands and wax secretion between females and males reflect their different needs for living habitats and different ecological strategies. Sciophilous male nymphs are with five types of wax glands, and the wax glands on the dorsum secrete a layer of wax filaments plausibly for protection against direct light irradiation. On the other hand, five types of wax glands were found on the abdomen of females. Heliophilous female nymphs hardly secrete any wax, but the wax glands located along the spiracle on the abdomen may help this insect to breathe. Female adults secrete wax filaments on eggs to protect them from predators and prevent themselves from sticking to each other. In summary, males appear to secreted wax for creating a shaded niche that fits their sciophilous life style, whereas females are likely to adopt an ecological strategy with thickened epidermis for heliophilous acclimatization and overwintering.

Green plants emit green leaf volatiles (GLVs) as a general damage response. These compounds act as signals for the emitter plant, neighboring plants, and even for insects in the ecosystem. However, when oral secretions from certain caterpillars are applied to wounded leaves, GLV emissions are significantly decreased or modified. We examined four caterpillar species representing two lepidopteran families for their capacity to decrease GLV emissions from Zea mays leaf tissue. We also investigated the source of the GLV modifying components in the alimentary tract of the various caterpillars. In Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), and Manduca sexta (Linnaeus) (Lepidoptera: Sphingidae), we found three distinct mechanisms to modify GLV emission: a heat-stable compound in the gut, a heat-labile enzyme in salivary gland homogenate (previously described in Bombyx mori (Linnaeus) (Lepidoptera: Bombycidae), and an isomerase in the salivary gland homogenate, which catalyzes the conversion of (Z)-3-hexenal to (E)-2-hexenal (previously described in M. sexta). These mechanisms employed by caterpillars to suppress or modify GLV emission suggest a counteraction against the induced indirect volatile defenses of a plant and provides further insights into the ecological functions of GLVs.

Minute pirate bugs of genus Orius (Wolff) are known important generalist predators of microinvertebrate pests and are therefore useful in many agricultural contexts. Effective sampling methods are thus of great importance to monitor Orius spp. populations. Sticky traps are one such sampling method; however, trap color must be carefully selected for the target insect species. In this study, we examined the most suitable sticky trap color (i.e., white, blue, or yellow) to capture Orius spp. individuals in eggplant Solanum melongena (Linnaeus) (Solanales: Solanaceae), Italian ryegrass Lolium multiflorum (Lamarck) (Poales: Poaceae), soybean Glycine max (Linnaeus) (Fabales: Fabaceae), and white clover Trifolium repens (Linnaeus) (Fabales: Fabaceae) fields. More Orius spp. adults were caught on blue and white traps than on yellow traps. The white traps also caught other insects, which hampered the counting of Orius spp. individuals and, therefore, reduced trapping efficiency. In addition, seasonal prevalence investigations showed that blue sticky traps had similar patterns to those of field observations. Thus, as the blue sticky trap can avoid capturing nontarget insects, we concluded that blue was the most suitable trap color for monitoring Orius spp. In addition, because blue sticky traps are more efficient and less-labor intensive, they can be useful as an alternative to field observations.

Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae), is a serious pest of vegetable, ornamental, and fruit crops. As a potential component of an integrated pest management (IPM) program, different plastic mulches including white-on-black, black-on-white, black-on-black, two metalized ultraviolet (UV)-reflective mulches, and a no mulch control were evaluated for managing T. palmi on six field-grown vegetable crops (eggplant, cucumber, squash, snap bean, Jalapeno pepper, and tomato) during the Fall of 2015 and 2016. Metalized reflective mulch significantly reduced the number of T. palmi in all vegetable crops compared with the other treatments. The highest numbers of T. palmi were observed on the white-on-black mulch and control treatments. The numbers of adults and larvae were highest on eggplant followed by cucumber, snap bean, squash, and Jalapeno pepper. The lowest numbers of T. palmi were observed on tomato plants. This study indicated that growing vegetable crops on metalized mulch is an effective method of reducing T. palmi populations in vegetable crops and should be considered in IPM programs for this insect species.

Brown stink bug, Euschistus servus (Say), is a damaging pest of corn, Zea mays L. (Cyperales: Poaceae), in the southeastern United States. In North Carolina, during the spring, winter-planted wheat, Triticum aestivum L. (Cyperales: Poaceae), serves as the earliest available crop host, and E. servus seems to prefer this crop over seedling corn. In the absence of wheat in the agroecosystem, weeds serve as a bridge host for a portion of overwintered E. servus populations until they move to corn and other subsequent crops. Our objective was to reduce densities of E. servus in corn by manipulating the weedy field borders with mowing and applications of dicamba herbicide. During the study, multiple species of stink bugs (n =16) were found associated with weed plots. However, E. servus was the predominant (>94%) stink bug species in the corn. In this farmscape, density of E. servus adults in the unmanaged weed plots began declining around the second week of May, followed by an increase in density in adjacent corn plots. This movement coincided with the seedling growth of corn. In 2016, applications of dicamba in the weedy field border resulted in a lower density of E. servus in herbicide-treated weed plots compared with untreated plots. Despite this difference, manipulations of weeds did not lead to any significant changes in density of E. servus adults in corn. Further evidence suggested that a prominent external source of E. servus, other than field-bordering weeds, in the farmscape was likely driving densities in corn.

Drosophila suzukii Matsumura is an invasive species affecting berry crops and cherries throughout North America, South America, and Europe. Previous research suggests that in temperate climates, the overwintering success of D. suzukii is likely dependent on access to food, shelter, and adequate cold hardening. We performed a multi-state study under field conditions for two winters to determine whether D. suzukii sex, phenotype (summer-morphotype, winter-morphotype), and life stage (adults, pupae) affected survival over time while recording naturally-occurring spatial and temporal variation in temperature. Access to food was provided and the flies were buried under leaf litter. Baited traps were deployed to determine whether local populations of D. suzukii were active throughout the winter season.The duration of exposure, mean daily temperature, and cumulative time below freezing significantly affected survival. Below freezing, D. suzukii survival was significantly reduced, particularly in northern locations. In contrast, we observed sustained survival up to 10 wk in southern locations among adults and pupae. Biotic factors also significantly affected survival outcomes: female survival was greater than male survival, winter-morphotype survival was greater than summer-morphotype survival, and adult survival was greater than pupal survival. In the north, wild D. suzukii were captured only in early winter, while in the south they were found throughout the winter. These data suggest that although adult D. suzukii may overwinter in sheltered microclimates, this ability may be limited in regions where the ground temperature, or site of overwintering, falls below freezing for extended durations.

Bollworm (Helicoverpa zea Boddie) (Lepidoptera: Noctuidae) can cause economic losses in both non-Bt and Bt cotton. Larvae modify their behavior in the presence of Bt by moving away from terminals faster in Bt cotton compared to non-Bt cotton and avoiding Bt-treated diets. Our objectives were to understand differences in bollworm egg and larvae populations within, and dispersal away from, non-Bt and Bt pyramided-toxin cotton. We conducted small plot experiments in 2016 and 2017 to monitor on-plant egg and larval numbers, and off-plant dispersal of larvae, from non-Bt and different Bt toxin pyramided cotton. Bollworm adults preferred to oviposit in most Bt toxin pyramids compared to non-Bt; this was likely unrelated to detection of Bt by adults, but rather density-dependent aversion from high larval populations. First instar numbers were similar in all non-Bt/Bt toxin pyramids and dispersed at a similar rate. Second through fifth instar numbers were higher in non-Bt than Bt toxin pyramids but dispersed equally from all non-Bt/Bt toxin pyramids, regardless of Bt pyramid type. Development times of larvae were often slower in Bt toxin pyramids compared to non-Bt. Fifth instars were found in, and dispersing from, Bt toxin pyramids containing Vip3A, raising concerns of resistance development. Furthermore, differences in oviposition rate among non-Bt/Bt toxin pyramids and slowed development rate of larvae on Bt varieties could create inconsistencies in generation times emerging from Bt and non-Bt hosts, which could contribute to resistance development.