The twig beetle, Pityophthorus pulchellus tuberculatus Eichhoff, infests dead branches of pines in western United States and Canada, including lodgepole pine, Pinus contorta Douglas, in northern Idaho. Adult broods overwintered in their host and emerged and colonized new hosts in late April. Males initiated galleries and were joined by up to seven females, each of which constructed an egg gallery radiating from a central chamber. Galleries had an average of 4.7 egg niches each with an egg that was large relative to the mother beetle. Two larval instars were recognized. Dentition of larval mandibles differed in shape from that in literature. Mature larvae pupated either in a cell excavated on the wood surface or in a cell below the wood surface. First-generation adults mined extensively in the inner bark and wood before emerging to infest new trees in late June. Their progeny became adults beginning in early August and likewise mined and fed on the inner bark and wood before overwintering. Predacious beetles present as larvae in the galleries included Enoclerus lecontei (Wolcott) (Coleoptera: Cleridae) and Lasconotus sp. (Coleoptera: Zopheridae). Parasitoid Hymenoptera reared from infested trees were Cosmophorus pityophthori Rohwer (Braconidae), Phasmidiasta n. sp. (Braconidae), Spathius sp. (Braconidae), Acerocephala n. sp. (Pteromalidae), Metacolus fasciatus Girault (Pteromalidae), Rhaphitelus maculatus Walker (Pteromalidae), Rhopalicus sp. (Pteromalidae), and an unidentified pteromalid.

With the recent increase in planting of fruit trees in southern Xinjiang, the intercropping of fruit trees and cotton has been widely adopted. From 2014 to 2016, a large-scale study was conducted in Aksu, an important agricultural area in southern Xinjiang, to compare the abundance and species composition of spider mites in cotton fields under jujube-cotton, apple-cotton, and cotton monocrop systems. The abundance of spider mites in cotton fields under both intercropping systems was generally higher than in the cotton monocrop. The species composition of spider mites also differed greatly between cotton intercropped with apple or jujube compared to the cotton monocrop. The relative proportion of Tetranychus truncates Ehara (Acari: Tetranychidae) in the species complex generally increased while that of another spider mite, Tetranychus dunhuangensis Wang (Acari: Tetranychidae), decreased under fruit tree-cotton systems. More attention should be paid to the monitoring and management of spider mites, especially T. truncates in this important region of China.

Carrot rust fly (CRF), Psila rosae (Fabricius, 1794) (Psilidae: Diptera) and carrot weevil (CW), Listronotus oregonensis (Le Conte, 1857) (Curculionidae: Coleoptera) are economic pests of carrot; larval tunneling on roots results in direct damage rendering the carrot unmarketable.The Holland Marsh in Ontario, Canada, is a major carrot production area. The ground-dwelling beetle (Coleoptera) fauna in commercial carrot fields in this region has not been described. In 2015 and 2016, eight commercial carrot fields were surveyed using pitfall traps to determine abundance and diversity of the ground-dwelling beetle complex. Research sites, which were used to evaluate the effectiveness of an existing integrated pest management (IPM) program, were also surveyed to determine the impacts of the IPM program on the natural enemy diversity, compared to insecticide-free sites. In total, 50 taxa and 4,127 individual ground-dwelling beetles were identified over the course of the 2 y. Known natural enemies of CRF and CW were identified and recovered in abundance. The abundance and diversity of ground-dwelling beetles among the commercial carrot fields varied greatly in 2015 and 2016 but was similar on research sites sprayed according to the IPM program compared to insecticide-free sites in both years. The importance of this research to promote conservation biological control through the naturalization of nonagricultural areas is discussed.

Japanese barberry (Berberis thunbergii de Candolle; Ranunculales: Berberidaceae) is an exotic shrub that has invaded woodland understories in the northeastern United States. It forms dense thickets providing ideal structure and microclimate for questing blacklegged ticks (Ixodes scapularis Say; Acari: Ixodidae). While there have been studies on the favorable habitat barberry provides blacklegged ticks, little has been studied on the relationship between barberry, vectors (ticks), and reservoirs (white-footed mice; Peromyscus leucopus Rafinesque; Rodentia: Cricetidae); specifically, the influence Japanese barberry has on the abundance of blacklegged ticks and Borrelia burgdorferi infection (Johnson, Schmid, Hyde, Steigerwalt, and Brenner; Spirochaetales: Spirochaetaceae) in mice. We studied the impacts of barberry treatment over the course of 6 yr to determine influence on encounter abundance with white-footed mice, encounter abundance with B. burgdorferi-infected mice, and juvenile blacklegged ticks parasitizing mice. Results from our study suggest that while both white-footed mouse and B. burgdorferi-infected mouse encounters remained similar between barberry treatment areas, juvenile tick attachment to mice was significantly greater in intact barberry stands ( x̄ = 4.4 ticks per mouse ± 0.23 SEM) compared with managed ( x̄ = 2.8 ± 0.17; P < 0.001) or absent ( x̄ = 2.2 ± 0.16; P < 0.001) stands. Results of this study indicated that management of barberry stands reduced contact opportunities between blacklegged ticks and white-footed mice. Continued efforts to manage Japanese barberry will not only allow for reestablishment of native plant species, but will also reduce the number of B. burgdorferi-infected blacklegged ticks on the landscape.

Winter wheat is Oklahoma's most widely grown crop, and is planted during September and October, grows from fall through spring, and is harvested in June. Winter wheat fields are typically interspersed in a mosaic of habitats in other uses, and we hypothesized that the spatial and temporal composition and configuration of landscape elements, which contribute to agroecosystem diversity also influence biological control of common aphid pests. The parasitoid Lysiphlebus testaceipes (Cresson; Hymenoptera: Aphidiinae) is highly effective at reducing aphid populations in wheat in Oklahoma, and though a great deal is known about the biology and ecology of L. testaceipes, there are gaps in knowledge that limit predicting when and where it will be effective at controlling aphid infestations in wheat. Our objective was to determine the influence of landscape structure on parasitism of cereal aphids by L. testaceipes in wheat fields early in the growing season when aphid and parasitoid colonization occurs and later in the growing season when aphid and parasitoid populations are established in wheat fields. Seventy fields were studied during the three growing seasons. Significant correlations between parasitism by L. testaceipes and landscape variables existed for patch density, fractal dimension, Shannon's patch diversity index, percent wheat, percent summer crops, and percent wooded land. Correlations between parasitism and landscape variables were generally greatest at a 3.2 km radius surrounding the wheat field. Correlations between parasitism and landscape variables that would be expected to increase with increasing landscape diversity were usually positive. Subsequent regression models for L. testaceipes parasitism in wheat fields in autumn and spring showed that landscape variables influenced parasitism and indicated that parasitism increased with increasing landscape diversity. Overall, results indicate that L. testaceipes utilizes multiple habitats throughout the year depending on their availability and acceptability, and frequently disperses among habitats. Colonization of wheat fields by L. testaceipes in autumn appears to be enhanced by proximity to fields of summer crops and semi-natural habitats other than grasslands.

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), has spread across North America and is causing serious economic damages. Current management of this pest is based primarily on use of insecticides, which can disrupt integrated pest management programs. Alternatively, biological control is a more benign management tactic. This study provides the first examination of potential impact of parasitoids and predators of pentatomid eggs in Minnesota. Over 2 yr, 10,074 fresh and 9,870 frozen H. halys eggs were deployed in two forest and two soybean habitats in St. Paul, Minnesota from June to August. Our results demonstrate that rates of parasitism and predation were low, accounting for only 0.4 and 3.7%, respectively, across years, habitats, and egg states. In general, the parasitoid Telenomus podisi Ashmead (Hymenoptera: Scelionidae), had higher impacts on H. halys eggs in soybean, and generalist predators were more prevalent in forest habitats. Overall, predation was higher on fresh versus frozen eggs, and parasitism was not consistent across egg states. Although the rates of H. halys mortality due to natural enemies were low, results of our study may be conservative estimates of their true impact. Also, sentinel egg mass surveys should account for undeveloped parasitoids to better quantify H. halys egg mortality by native parasitoids. Alternative management tactics, such as the introduction of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), could be considered to improve biological control of H. halys. Our findings serve as the foundation for future work on biological control of this pest and other pentatomids.

Supporting managed honey bees by pasturing in natural landscapes has come under review due to concerns that honey bees could negatively impact the survival of wild bees through competition for floral resources. Critique and assessment of the existing body of published literature against our criteria focussing on studies that can support best management resulted in 19 experimental papers. Indirect measures of competition examining foraging patterns and behavior yielded equivocal results. Direct measures of reproduction and growth were investigated in only seven studies, with six indicating negative impacts to wild bees from the presence of managed honey bees. Three of these studies examined fitness impacts to Bombus Latreille and all three indicated reduced growth or reduced reproductive output. Because there is a severe lack of literature, yet potential that honey bee presence could negatively impact wild bees, exemplified with bumble bee studies, we advocate for further research into the fitness impacts of competition between managed and wild pollinators. Conservative approaches should be taken with respect to pasturing honey bees on natural lands with sensitive bumble bee populations. Correspondingly, forage opportunities for honey bees in managed, agricultural landscapes, should be increased in an effort to reduce potential pressure and infringement on wild bee populations in natural areas.

The maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), is a major insect pest of stored grain. This study evaluated resistance of grain of 26 sorghum genotypes, Sorghum bicolor (L.) Moench, to maize weevil under laboratory conditions. Three female and two male newly emerged maize weevils were reared with 5 g of grain in each of 10 vials for each of the 26 sorghum genotypes in a laboratory experiment. The weevils and grain of each genotype were scored once every 3 wk for a total of five times during 105 d. The numbers of live and newly emerged maize weevils, dead weevils from the initial population, damage score (scale of 1–5), and grain weight loss were used to indicate resistance. The least percentage weight loss of 23.9 and 24.1% was recorded for sorghum genotypes Sureño and (5BRON151*Tegemeo)-HG7, respectively. Genotypes B.HF8 and (A964*P850029)-HW6 had the most weight loss, 70.6 and 67.7%, at 105 d after infestation. Genotypes B.HF8 and (A964*P850029)-HW6 consistently exhibited the highest numbers of maize weevil, 63 and 84, per vial at 105 d after infestation. Sorghum genotypes Sureño, (SV1*Sima/IS23250)-LG15, (5BRON151*Tegemeo)-HG7, and (B35*B9501)-HD9 ranked among the top four genotypes with least damage rating more often than any other genotype across the five sampling dates. On the other hand, genotypes B.HF8, (A964*P850029)-HW6, (Segaolane*WM#322)LG2, and (Tx2880*(Tx2880*(Tx2864*(Tx436*(T x2864*PI550607)))))-PR3-CM1 were more often ranked among the top four genotypes with the highest damage rating. Our results indicate that grain of genotype Sureno is most resistant to the maize weevil among screened genotypes.

Gall formation is induced by an insect, which changes normal plant development and results in the formation of a new organ, following distinct stages of metabolic and developmental alterations. Research on mechanisms of recognition and responses to biotic stress may help to understand the interactions between galling aphids and their host plants. In this study, Tetraneura ulmi L. (Hemiptera: Eriosomatinae) galls and Ulmus pumila L. (Rosales: Ulmaceae) leaves were used as a model. Concentrations of hydrogen peroxide (H₂O₂) and thiobarbituric acid reactive substances, electrolyte leakage, as well as the activity of ascorbate peroxidase, guaiacol peroxidase, and catalase (CAT) were determined in galls and two parts of galled leaves (with and without visible damage). Biochemical analyses were performed at three stages of gall development: initial, fully developed, and mature galls. A slight increment in H₂O₂ content with a strong enhancement of ascorbate peroxidase and CAT activities were observed in galls and galled leaves in the first stage. In subsequent stages of gall development, a progressing increase in H₂O₂ production and cell membrane damage was associated with declining antioxidant enzyme activities, especially in gall tissues. The stages of gall development are likely to be part of cell death triggered by aphid feeding. It seems that the gall is the result of a biochemical struggle between the host plant and the gall inducer.

Atmospheric CO₂ level arising is an indisputable fact in the future climate change, as predicted, it could influence crops and their herbivorous insect pests. The growth and development, reproduction, and consumption of Spodoptera litura (F.) (Lepidoptera: Noctuidae) fed on resistant (cv. Lamar) and susceptible (cv. JLNMH) soybean grown under elevated (732.1 ± 9.99 μl/liter) and ambient (373.6 ± 9.21 μl/liter) CO₂ were examined in open-top chambers from 2013 to 2015. Elevated CO₂ promoted the above- and belowground-biomass accumulation and increased the root/ shoot ratio of two soybean cultivars, and increased the seeds' yield for Lamar. Moreover, elevated CO₂ significantly reduced the larval and pupal weight, prolonged the larval and pupal life span, and increased the feeding amount and excretion amount of two soybean cultivars. Significantly lower foliar nitrogen content and higher foliar sugar content and C/N ratio were observed in the sampled foliage of resistant and susceptible soybean cultivars grown under elevated CO₂, which brought negative effects on the growth of S. litura, with the increment of foliar sugar content and C/N ratio were greater in the resistant soybean in contrast to the susceptible soybean. Furthermore, the increment of larval consumption was less than 50%, and the larval life span was prolonged more obvious of the larvae fed on resistant soybean compared with susceptible soybean under elevated CO₂. It speculated that the future climatic change of atmospheric CO₂ level arising would likely cause the increase of the soybean yield and the intake of S. litura, but the resistant soybean would improve the resistance of the target Lepidoptera pest, S. litura.

Atmospheric temperature increases along with increasing atmospheric CO₂ concentration.This is a major concern for agroecosystems. Although the impact of an elevated temperature or increased CO₂ has been widely reported, there are few studies investigating the combined effect of these two environmental factors on plant–insect interactions. In this study, plant responses (phenological traits, defensive enzyme activity, secondary compounds, defense-related gene expression and phytohormone) of Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae) -susceptible and resistant rice under various conditions (environment, soil type, variety, C. medinalis infestation) were used to examine the rice–C. medinalis interaction. The results showed that leaf chlorophyll content and trichome density in rice were variety-dependent. Plant defensive enzyme activities were affected environment, variety, or C. medinalis infestation. In addition, total phenolic content of rice leaves was decreased by elevated CO₂ and temperature and C. medinalis infestation. Defense-related gene expression patterns were affected by environment, soil type, or C. medinalis infestation. Abscisic acid and salicylic acid content were decreased by C. medinalis infestation. However, jasmonic acid content was increased by C. medinalis infestation. Furthermore, under elevated CO₂ and temperature, rice plants had higher abscisic acid content than plants under ambient conditions. The adult morphological traits of C. medinalis also were affected by environment. Under elevated CO₂ and temperature, C. medinalis adults had greater body length in the second and third generations. Taken together these results indicated that elevated CO₂ and temperature not only affects plants but also the specialized insects that feed on them.

The genus Monochamus Dejean (Coleoptera: Cerambycidae) includes large, woodboring, longhorned beetles, which colonize pine trees in North America. Many authors have classified the genus as saprophagous, but one recent study reported successful colonization of standing jack pine trees (Pinus banksiana Lamb.) (Pinales: Pinaceae) following severe wind disturbance in Minnesota. We tested whether two Monochamus species native to the southeastern United States (M. titillator (Fabricius) and M. carolinensis (Olivier)) could successfully colonize healthy shortleaf pines (Pinus echinata Mill.) (Pinales: Pinaceae) in recently harvested stands without coincident abiotic or biotic stressors, such as lightning strikes or bark beetle attacks. We attached commercially available semiochemical lures, including monochamol, ethanol, and ipsenol, to healthy shortleaf pine trees and observed Monochamus spp. oviposition response. Egg development was monitored following oviposition by harvesting attacked trees and dissecting oviposition pits. High numbers of oviposition pits were observed on trees treated with lures containing the bark beetle pheromone ipsenol and pits were highly concentrated on the tree bole near lures. Although egg deposition occurred, pit dissection revealed large amounts of resin present in almost all dissected pits and that egg hatch and subsequent larval development were rare. Our results demonstrate that southeastern Monochamus spp. are unlikely to be primary pests of healthy shortleaf pines due to resinosis.To better understand the host finding behavior of these two Monochamus species, we also conducted trapping trials with several semiochemical combinations. Both species and sexes demonstrated similar attraction to compounds, and the most attractive lure combined host volatiles, pheromone, and sympatric insect kairomone.

We know numerous abiotic factors strongly influence crop plants.Yet we often know much less about abiotic effects on closely interacting organisms including herbivorous insects.This lack of a whole-system perspective may lead to underestimating the threats from changing factors. High soil salinity is a specific example that we know threatens crop plants in many places, but we need to know much more about how other organisms are also affected. We investigated how salinity affects the soybean aphid (SBA; Aphis glycines Matsumura; Hemiptera: Aphididae) on soybean plants (Glycine max [L.] Merr.; Fabales: Fabaceae) grown across a range of saline conditions. We performed four complementary greenhouse experiments to understand different aspects of how salinity might affect SBA. We found that as salinity increased both population size and fecundity of SBA increased across electrical conductivity values ranging from 0.84 to 8.07 dS m^-1. Tracking individual aphids we also found they lived longer and produced more offspring in high saline conditions compared to the control. Moreover, we found that salinity influenced aphid distribution such that when given the chance aphids accumulated more on high-salinity plants.These results suggest that SBA could become a larger problem in areas with higher salinity and that those aphids may exacerbate the negative effects of salinity for soybean production.

This project investigated associational interactions (associational resistance or susceptibility) between native and non-native trees commonly found in urban landscapes in the southeastern United States. Non-native plants offer limited ecological services because few native herbivore species are capable of feeding on them. In a 2-yr field study, abundance and species richness of caterpillars, plant damage, and herbivore natural enemies were evaluated in plots where a native red maple (Acer rubrum L. [Sapindales: Aceraceae]) was planted singly (no neighbors) or interplanted with either non-native non-congeneric crepe myrtles (Lagerstroemia indica L. [Myrtales: Lythraceae]), non-native congeneric Norway maples (Acer platanoides L. [Sapindales: Aceraceae]), or other red maples. Dryocampa rubicunda Fabricius (Lepidoptera: Saturniidae) accounted for most of the damage and caterpillar abundance.There were few significant differences between treatment groups in the establishment year of 2014, but in 2015 there was greater tree defoliation, caterpillar abundance, and caterpillar species richness when red maples were surrounded by crepe myrtles. We describe this as a biological fence effect in which the presence of crepe myrtle causes caterpillars to accumulate on the focal red maples over multiple generations. Red maples interplanted with Norway maple neighbors hosted an intermediate abundance and species richness of caterpillars compared to red maples interplanted with crepe myrtles and those with other red maples, indicating a spillover of herbivores to the related maple. No significant trends in insect natural enemy abundance or diversity between treatment groups were detected. These results highlight the necessity of considering plant associational interactions in context of species origin to alleviate pest outbreaks and develop sustainable landscape designs.

Because of concerns over recent declines in overall biodiversity in suburban areas, homeowners are attempting to improve the ecological functioning of their landscapes by incorporating native plants. Native plants are important for supporting native herbivorous insects, but it is unknown whether the native plants that are commercially available, typically cultivated varieties (cultivars) of a single genotype, are equally effective as food sources as the local, wildtype plants. We compared the hemipteran communities feeding on cultivars and wild-propagated plants for four species of native perennials commonly used as ornamentals. Of 65 hemipteran species collected, 35 exhibited a preference for some plant species over others, indicating a high degree of host-plant specialization. Moreover, the insect community associated with cultivars was distinct from the insect community associated with wild-type plants for each plant species, with three to four insect species accounting for most of the observed difference. Total insect abundance and insect biomass differed between cultivars and wild-propagated plants, but the direction of the difference changed over time and was not consistent among plant species. Species richness and a diversity index (the Q statistic) did not differ between cultivars and wild-type plants. These data suggest that abundance and diversity of hemipteran insects does not depend on the source of the plant material per se, but rather on the particular characteristics of cultivars that distinguish them from the wild type.

The effects of climate change and extreme weather conditions on plants and animals have been documented extensively. However, the possible effects of these factors on plant–insect interactions in subtropical regions are relatively unexplored. The present study investigated the consequences of elevated CO₂ and temperature on a tritrophic system (plant–insect–parasitoid) in subtropical regions. The experimental conditions were as follows: ambient CO₂, 500 ppm; elevated CO₂, 1,000 ppm; ambient temperature, 24/21°C (day/night); and elevated temperature, 29/26°C (day/night). Brassica oleracea var. italica foliar primary metabolites were quantified 6 wk after germination and insect feeding bioassays were subsequently conducted. Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) larvae were fed directly on these plants until pupal development. In addition, the second instar S. litura larvae were exposed to the parasitoid Snellenius manilae (Ashmead) (Hymenoptera: Braconidae) under the same plant treatment conditions. The results suggested that elevated CO₂ has a major influence on plant performance and foliar quality. Elevated CO₂ also affected the leaf area, foliar fresh and dry weights, and total nitrogen and carbohydrate contents. Elevated temperature reduced the larval development time and increased the growth rate of S. litura. Sn. manilae had a higher parasitism rate and shorter development time at elevated temperature compared with ambient temperature. These results suggested that the dynamic and communal structure of S. litura and its parasitoids requires comprehensive evaluation in terms of the changes in nutritional quality (bottom-up control) caused by the interactive effects of CO₂ and temperature.

We investigated the impact of an invasive ant species from Europe, Myrmica rubra (L.), on a myrmecochorous system (seeds dispersed by ants) in its invaded range in North America. We assessed: 1) how M. rubra process the myrmecochorous diapsores (seeds and elaiosome as a single dispersal unit transported by ants) in comparison with native ants; 2) its preference for common native and invasive diaspore species relative to native ants; 3) how far they disperse diaspores in the field; and 4) the diaspore removal rate by invertebrates and vertebrates in infested areas compared to noninvaded sites. Field experiments demonstrated higher diaspore removal rates over a 10-min and 24-h period by M. rubra compared to native ants. M. rubra’s diaspore dispersal distance was 40% greater compared to native ants. In two of three laboratory studies and one field study, there was no significant difference between the seed species which M. rubra and native ants selected. Our data suggest no long-term deleterious effects of M. rubra’s invasion on diaspore dispersal in the Maine plant community that is comprised of both native and invasive species. This implies that M. rubra benefits from the myrmechorous plant lspecies' diaspores by increasing their dispersal range away from the parent plant and potentially reducing seed predation. However, it is not known whether the fact that the native ant fauna and M. rubra are attracted to the same plant lspecies' diaspores creates a high level of competition between the ants with deleterious effects on the native ant community.

The neural constraint hypothesis is one of the central ideas for the understanding of insect–plant interaction but there are still knowledge gaps in the data for foraging behavior and the performance of herbivores, and particularly florivores.We used a floriphilic katydid, Phaneroptera brevis (Serville, 1838) (Orthoptera:Tettigoniidae) and a naturalized weed, Bidens pilosa L. (Asteraceae) in caged experiments in an insectary to answer these questions: 1) How does the foraging performance of the floriphilic katydid vary when exposed to a choice in the number of capitula and types of florets of B. pilosa? 2) Does the foraging performance of the katydid, when exposed to multiple choices, improve with time, and are between-individual differences in foraging performance consistent? We observed that having more choices in the floret types and number of capitula is generally associated with a reduced foraging performance of the katydids. Floret types and number of capitula, however, did not have an interactive effect on foraging performance. We also found that the differences in foraging performance in response to choice tend to be consistent between katydids but each katydid became more efficient and decisive over time.That learning and experience can improve the foraging performance of the katydid has provided us with some insights as to how a continuum of efficient and inefficient katydids can be maintained in a population.

The spotted clover moth, Protoschinia scutosa (Denis & Schiffermüller) (Lepidoptera: Noctuidae), is an important polyphagous pest that is widely distributed in the world. P. scutosa overwinters as pupae in agricultural soils in Northern China. Yet, it is unclear whether P. scutosa also engages in seasonal migration over mid- to long-range distances. In this study, we employ light trapping, field surveys, and ovarian dissection of captured adults over a 2003–2015 time period to assess P. scutosa migration in Northern China. Our work shows that P. scutosa migrates across the Bohai Strait seasonally; the mean duration of its windborne migration period was 121.6 d, and the mean trapping number was 1053.6 moths. Nightly catches of P. scutosa were significantly different between months, but the differences between years were not significant. During 2009–2011 and 2013, the monthly proportion of migrating females (65.5%) was significantly higher than that of males and showed no difference between months. In May to June, the majority of females (May: 63.0%; June: 61.1%) were mated individuals with relatively high level of ovarian development; however, in August and September, most females were unmated. The mean proportion of mated females was significantly different across months but did not differ between years. The results of longterm searchlight trapping and ovarian dissection indicate that P. scutosa exhibits a seasonal characteristic of typical population dynamics and reproductive development of migratory insects. Our work sheds light upon key facets of P. scutosa ecology and facilitates the future development of pest forecasting systems and pest management schemes.

Spotted-wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), is an invasive pest of softskinned fruits across the globe. Effective monitoring is necessary to manage this pest, but suitable attractants are still being identified. In this study, we combined lures with fermenting liquid baits to improve D. suzukii trapping specificity and attractiveness. We also measured the efficiency and specificity of baits/lures during different times of the season; the reproductive status of females among baits/lures; and the effects of locations and crop type on these response variables. We developed a metric that combined mating status and fat content to determine differences in types of females attracted. Lures utilizing yeast and sugar-based volatiles trapped the most D. suzukii. The addition of a commercial lure to yeast and sugar-based lures increased catches in most locations, but was also the least specific to D. suzukii. Apple juice-based chemical lures tended to be most specific to D. suzukii, while lures comprised of a singular attractant tended to trap more D. suzukii with a higher reproductive potential than combinations of attractants. Trap catch and lure specificity was lower during fruit development than fruit ripening. While catch amounts varied by geographic location and crop type, attractants performed similarly relative to each other in each location and crop. Based on the metrics in this study, the yeast and sugar-based attractants were the most effective lures. However, further work is needed to improve early season monitoring, elucidate the effects of physiological status on bait attraction, and understand how abiotic factors influence bait attraction.

Fermentation volatiles attract a wide variety of insects and are used for integrated pest management. However, identification of the key behavior modifying chemicals has often been challenging due to the time consuming nature of thorough behavioral tests and unexpected discrepancies between laboratory and field results. Thus we report on a multiple-choice bioassay approach that may expedite the process of identifying field-worthy attractants in the laboratory. We revisited the four-component key chemical blend (acetic acid, ethanol, acetoin, and methionol) identified from 12 antennally active wine and vinegar chemicals for Drosophila suzukii (Matsumura) (Diptera: Drosophilidae). The identification of this blend took 2 yr of continuous laboratory two-choice assays and then similarly designed field trials. This delay was mainly due to a discrepancy between laboratory and field results that laboratory two-choice assay failed to identify methionol as an attractant component. Using a multiple-choice approach, we compared the co-attractiveness of the 12 potential attractants to an acetic acid plus ethanol mixture, known as the basal attractant for D. suzukii, and found similar results as the previous field trials. Only two compounds, acetoin and, importantly, methionol, increased attraction to a mixture of acetic acid and ethanol, suggesting the identification of the four-component blend could have been expedited. Interestingly, the co-attractiveness of some of the 12 individual compounds, including a key attractant, methionol, appears to change when they were tested under different background odor environments, suggesting that background odor can influence detection of potential attractants. Our findings provide a potentially useful approach to efficiently identify behaviorally bioactive fermentation chemicals.

Hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an exotic pest of eastern hemlock, Tsuga canadensis (L.) Carrière (Pinales: Pinaceae), in the eastern United States.Two commonly used insecticides to manage adelgid are imidacloprid, a systemic neonicotinoid insecticide, and horticultural oil, a refined petroleum oil foliar spray. We have investigated the influence of imidacloprid and horticultural oil on spider abundance at different canopy strata in eastern hemlock. In total, 2,084 spiders representing 11 families were collected from the canopies of eastern hemlock. In beat-sheet and direct observation samples, the families Theridiidae, Araneidae, Salticidae, and Anyphaenidae were the most abundant. Significantly higher numbers of spiders were recorded on untreated control trees compared with trees treated with imidacloprid using soil drench and soil injection applications. Spider abundance in trees injected with imidacloprid and horticultural oil applications did not significantly differ from control trees. Spider abundance was significantly greater in the top and middle strata of the canopy than in the bottom stratum, where imidacloprid concentrations were the highest. Regression analysis showed that spider abundance was inversely associated with imidacloprid concentration.This research demonstrates that imidacloprid, when applied with selected methods, has the potential to result in reductions of spider densities at different strata. However, slight reductions in spider abundance may be an acceptable short-term ecological impact compared with the loss of an untreated hemlock and all the associated ecological benefits that it provides. Future studies should include investigations of long-term impact of imidacloprid on spiders associated with eastern hemlock.

We investigated associative learning of food odors by the European paper wasp Polistes dominula Christ (Hymenoptera: Vespidae) because of consistent low rates of attraction to food materials in laboratory assays. We hypothesized that wasps in nature exhibit nonspecific food-finding behavior until locating a suitable food, and then respond more strongly and specifically to odors associated with that food reward. Female P. dominula workers exhibited higher rates of attraction in a flight tunnel to piped odors of fermented fruit purees following previous experience with that puree, compared to wasps with no prior experience with the fermented fruits. Attraction behavior included upwind-oriented flight and casting within the odor plume, indicative of chemoanemotaxis. Synthetic chemicals representative of volatiles P. dominula may encounter in nature while foraging was also tested. Similar increases in attraction responses occurred following feeding experience with a sugar solution that included either 3-methyl-1-butanol or pear ester, but not eugenol. These experimental results support the hypothesis of associative learning of food odors in P. dominula. We discuss the ecological relevance of our results and suggest an alternative approach to trap paper wasps in pest situations utilizing learned chemical attractants.

The coffee white stemborer, Xylotrechus quadripes Chevrolat (Coleoptera: Cerambycidae), feeds primarily on Coffea arabica L. (Gentianales: Rubiaceae) with its egg, larva, and pupa being developed within the trunk. The detection of chemosensory-related cues linked to adult mating, host seeking, and recognition is driven by three chemoreceptor gene repertoires of odorant (ORs), gustatory (GRs), and ionotropic (IRs) receptors as well as sensory neuron membrane proteins (SNMPs). Yet, information on these genes involved in chemoreception is unavailable in X. quadripes and relatively poor in the cerambycid beetles. Here, we presented the identification of four chemosensory transmembrane proteins from the antennal transcriptome of X. quadripes, including 33 ORs, five GRs, 18 IRs, and four SNMPs. Phylogenetic analysis classified the ORs into groups 1, 2, 3, 7, and olfactory coreceptor (Orco), showing three potential candidates (OR13, OR17, and OR21) for the sensing of male sex pheromones. The IRs were clustered into 10 orthologous groups, with additional copies for IR41a, IR64a, and IR75 clades. Four SNMPs were distributed in four independent clades, possibly representing a complete set in this species. Expression profiles revealed that all the genes were highly expressed in antennae, suggesting their olfactory roles. In addition, most of the genes showed the expression in nonantennal tissues including thoraxes, abdomens, wings, and legs, suggesting their involvement in nonchemosensory functions. Of notice, a highly conserved coreceptor IR25a displayed male-biased expression in the antennae, as the first presence in the cerambycid beetles. This study has established reference resources for understanding the mechanisms underlying the interactions between/within this beetle and its host plants.

Biological invasions provide a unique opportunity to gain insight into basic biological processes occurring under new circumstances. During the process of establishment, exotic species are exposed to various stressors which may affect their development. Presence of the stressors is often detected by measurements of left–right body asymmetry, which consists of two main components: fluctuating asymmetry and directional asymmetry. Fluctuating asymmetry constitutes random differences between the two body sides, whereas directional asymmetry occurs when a particular trait is bigger on one of the sides. The relation between these two asymmetry components is still not fully understood. Our goal was to investigate the potential differences in asymmetry patterns between native and invasive populations of Tetropium fuscum (Fabr. 1787) (Coleoptera: Cerambycidae), a harmful forest pest native to Europe and introduced to North America. Wing asymmetry assessment was based on the geometric morphometrics of hind wings. We found that specimens from invaded area were markedly smaller and have more asymmetric wings than individuals from native population, suggesting some unfavorable conditions in the invaded area. Moreover, we found significant directional asymmetry in the native but not in the invasive population. On the other hand, differences between left and right hind wings were similar in the native and invasive populations, in terms of direction. This suggests that a high level of fluctuating asymmetry in the invasive population may blur the intrinsic directional asymmetry and hinder its detection. Our data show that fluctuating asymmetry has a potential as an indicator of developmental stress in invasive species.

Heterobostrychus aequalis (Waterhouse) (Coleoptera: Bostrychidae) and Lyctus africanus Lesne (Coleoptera: Lyctidae) are distributed mainly in tropical regions. The primary mechanism allowing these beetles to survive in cold and arid habitats beyond the native tropical region is a reduced water loss rate. This study investigated the water relations of these two beetles in relation to their size, ontogenetic traits, and behavioral characteristics to determine how they can survive in desiccated wood. H. aequalis and L. africanus share similar water characteristic with beetles living in desert and woodlands. They have high percentage total body water (%TBW) content (58.38 ± 1.86% to 63.20 ± 1.38%), but low %TBW loss (4.28 ± 1.02% to 48.26 ± 8.28%) due to their impermeable cuticle (cuticular permeability [CP] value: 0–15.57 ± 4.90 μg cm^–2 h^–1 mmHg^–1) at all life stages. Although the larvae of L. africanus exhibited relatively high %TBW loss, they had relatively shorter development times that minimized prolonged exposure to dry conditions inside the wood. The aggregative behavior of the adult could be responsible for maintaining a low water loss rate to compensate for their small body size. In contrast, the larvae of H. aequalis had larger body size and significantly lower CP values, allowing them to survive in the desiccated wood for a longer period of time. These results demonstrate the remarkably sophisticated strategies that insects employ as a trade-off between body size, ontogenetic development, and insect sociality (aggregative and non-aggregative behavior) to maintain their water balance in xeric environments.

Diapause and cold tolerance can profoundly affect the distribution and activity of temperate insects. Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), an alien invasive species from Asia, enters a winter dormancy in response to environmental cues. We investigated the nature of this dormancy and its effects on H. halys cold tolerance, as measured by supercooling points, lower lethal temperatures, and overwintering field mortality. Dormancy was induced by rearing individuals in the laboratory or under field conditions. We confirmed H. halys dormancy to be a state of diapause and not quiescence, and the life stage sensitive to diapause-inducing cues is between the second and fifth instar. In the laboratory, supercooling points of diapausing adults reached significantly lower temperatures than nondiapausing adults, but only when given enough time after imaginal ecdysis. Supercooling points of diapausing adults in overwintering microhabitats also decreased over time. Diapause increased adult survival after acute cold exposure in the laboratory and prolonged cold exposure in the field. Following diapause induction in the laboratory, changes to temperature and photoperiod had no significant effect on lower lethal temperatures and changes to photoperiod had no effect on supercooling points. Additionally, induction of diapause in the laboratory did not result in significantly different cold tolerance than natural field induction of diapause. This work demonstrates that H. halys diapause confers greater cold tolerance than a nondiapausing state and likely improves the probability of successful overwintering in some temperate climates. Hence, knowledge of diapause status could be used to refine forecasts of H. halys overwintering field mortality.

Although laboratory observations provide basic knowledge of the development and reproduction of predacious and phytophagous mites, little is known of their behavior under natural conditions. Using a closed system designed to simulate natural climate patterns, we investigated the development and reproduction of the predatory mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) and the pest mite Tetranychus urticae Koch (Acari: Tetranychidae) at air temperatures typical of June to October at three latitudes (Aomori,Tottori, and Naha) in Japan. The peaks of development in both species showed similar trends at each location. The shortest developmental times for both species were observed during August in Aomori, from July to September in Tottori and during August and September in Naha. Development of T. urticae was not completed during October in Aomori due to the decreased air temperature. High reproduction (number of eggs produced during 5 d from the first oviposition) of N. californicus was attained at the conditions that shortened the developmental times (i.e., high-temperature months). T. urticae showed a reproduction trend similar to that of N. californicus except for the low number of eggs produced during August in Naha due to the high mortality of adult females and during October in Tottori due to diapause incidence. This information is in agreement with field observations and together might be useful for planning biological control programs for phytophagous mites and for successful establishment of predacious mites in new habitats.

Environmental challenges presented by temperature variation can be overcome through phenotypic plasticity in small invasive ectotherms. We tested the effect of thermal exposure to 21, 18, and 11°C throughout the whole life cycle of individuals, thermal exposure of adults reared at 25°C to 15 and 11°C for a 21-d period, and long (14:10 hr) and short (10:14 hr) photoperiod on ovary size and development in Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) cultured from a recently established population in Topeka, Kansas (United States). Examination of the response to temperature and photoperiod variation in this central plains population provides insight into the role of phenotypic plasticity in a climate that is warmer than regions in North America where D. suzukii was initially established. We found both low temperature and short photoperiod resulted in reduced ovary size and level of development. In particular, reduced ovary development was observed following exposure to 15°C, indicating that ovary development in females from the central plains population is more sensitive to lower temperature compared with populations examined from the northern United States and southern Canada. We also provide evidence that D. suzukii reared at 25°C are capable of short-term hardening when exposed to -6°C following 4°C acclimation, contrary to previous reports indicating flies reared at warm temperatures do not rapidly-cold harden. Our study highlights the central role of phenotypic plasticity in response to winter-like laboratory conditions and provides an important geographic comparison to previously published assessments of ovary development and short-term hardening survival response for D. suzukii collected in cooler climates.

Agelastica alni L. (Coleoptera: Chrysomelidae) is a common beetle pest of alder trees (Alnus incana L.) in forests and parks across Estonia.The supercooling ability and capacity to survive low temperature exposure changes temporally. Relatively high unimodal supercooling point (SCP) levels (with a mean value of -6 to -8°C) were characteristic of the beetles in September during their diapause induction period, in April when the beetles had terminated their diapause development and in May when they started to reproduce. During their deep diapause period the SCPs of beetles had a bimodal distribution. Some beetles decreased their SCPs to -14 to -19°C while others retained a high SCP value of -6 to -8°C. Most vulnerable to low temperature were overwintered active beetles in May; after 1 h exposure their LTemp₅₀ (median lethal temperature) was -6.3°C. In September with the onset of diapause tolerance of beetles started to increase, LTemp₅₀ = -7.7°C. Beetles were most cold tolerant during their deep diapause period with LTemp₅₀ < -12.0°C. A. alni beetles use one of two different strategies for overwintering, some are freeze-tolerant while others are freeze-avoidant. The freeze-avoidant beetles with low SCP (-12 to -15°C) acquired greater cold tolerance than those with higher SCP (-6 to -8°C), with LTemp₅₀ = -13.7°C and LTemp₅₀ = -11°C, respectively.

Many lady beetles expel an autogenously produced alkaloid-rich ‘reflex blood’ as an antipredator defense. We conducted an experiment to determine whether there was a measurable fitness cost associated with the daily induction of this defensive behavior, and whether costs differed between native (Coccinella novemnotata Herbst (Coleoptera: Coccinellidae)) and invasive species (Coccinella septempunctata L. (Coleoptera: Coccinellidae) and Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)). Newly mated females were provided a restricted or unrestricted amount of aphids and were bled for 10 d. We measured the mass of reflex blood produced and the total number and viability of eggs laid per day. The amount of reflex blood released per day increased for C. septempunctata at the restricted level and did not change for any other species-diet level combination. We did not detect a significant cost of reflex bleeding on the quantity or viability of eggs laid by any species, even at the restricted aphid level. Remarkably, bled individuals at the ad libitum level laid significantly more viable eggs compared to controls. All species laid significantly fewer total eggs (49–69% fewer) at the low versus high aphid level.These results demonstrate that while resource scarcity has a negative impact on fecundity, repeated use of the reflex bleeding defense system does not. These results support the findings of other reports and strongly suggest that adult lady beetles incur no measurable physiological costs related to the induction of the reflex-bleeding defense.

Cereal leaf beetles (CLBs) are described as an invasive pest of small grain cereals in many regions worldwide. Prediction models aimed to prevent yield losses caused by these feeding insects have been developed by researchers all over the world. As a foundation for many of these prediction models, it is known that a specific number of heat units, or growing degree days (GDDs), is required for an insect to complete a certain physiological process. In this paper, we overview the existing GDD models for CLBs. Furthermore, we used our Belgian input data to compare model predictions with our own observations.Though, the existing models were not able to predict the seasonal trends present in our data: the occurrence of various life stages were monitored earlier then the model predicted. Hence, a weighted GDD model was tested on the data as well: the accumulated GDDs during certain periods were balanced according to the significance of this period for the insect. Rainfall and/or relative humidity were included as well. Based on these selected variables, multiple linear regression models, ridge regression models, and regression trees were fitted. This approach performed considerably better compared to the simple accumulation of GDD. However, based on cross-year cross-location validation method, to gain insight in the future performance of the models, the accuracy was still too low to serve as an accurate warning tool.

The American serpentine leaf miner, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae), is a perennial pest of leguminous crops in the Mediterranean region. A life table was constructed for L. trifolii infesting broad bean, Vicia faba L., in northern Egypt. Key factor analysis was used to rank sources of immature mortality over two seasons. Leaf miners had three successive generations, and a partial fourth, in each year, with peak abundance in March–April. Less than 15 and 22% of L. trifolii survived to adult in seasons one and two, respectively. The largest contributor of immature leaf miner mortality in both seasons was unknown (41.2 and 39.1% of total mortality, respectively), and likely comprised a combination of abiotic factors, parasitoid-inflicted mortality (host-feeding), and predation. Parasitism was second, contributing 36.2 and 35.6% of total mortality in the two seasons, respectively, primarily due to larval parasitism by Diglyphus isaea (Walker) (Hymenoptera: Eulophidae), and low levels of larval–pupal parasitism by Opius pallipes Wesmael (Hymenoptera: Braconidae) and Halticoptera circulus (Walker) (Hymenoptera: Pteromalidae). Residual mortality resulted from malformed pupae or failed adult emergence. Key factor analysis revealed malformation to be the major cause of pupal mortality. Sequential regression confirmed that unknown mortality and D. isaea were the top stage-specific factors, both acting on larvae. Parasitoid abundance tracked host abundance across generations, but density dependence was not observed for any mortality factor, and the magnitudes of regression slopes were small. The results indicate the potential importance of conservation biological control in management of L. trifolii, given that naturally occurring parasitoids and other biotic/abiotic factors exert significant mortality on immature leaf miners.