Aggregations of Thaumatomyia glabra (Diptera: Chloropidae) were observed on flowers of Iris pallida Lamarck (Asparagales: Iridaceae), whereas no T. glabra (Meigen) were observed on nearby Iris germanica L. flowers. Sampling of T. glabra on I. pallida flowers revealed the presence of males only. In a previous study, T. glabra males were attracted to methyl anthranilate. We found methyl anthranilate in extracts of I. pallida flowers on which T. glabra aggregated, but not in extracts of I. germanica flowers. Applying methyl anthranilate to I. germanica flowers elicited attraction of T. glabra to the flowers. This study suggests that I. pallida flowers may attract T. glabra males to aggregate because they release the known attractant, methyl anthranilate, whereas I. germanica flowers may not be attractive because they do not release methyl anthranilate.

Recent theoretical work suggests that two ineffective control agents can provide effective biological control when coupled together. We explore the implications of this work with the system of coffee leaf rust (CLR), caused by the fungal agent Hemileiae vastatrix, and two of its natural enemies, a fungal pathogen (Lecanicillium lecanii) and a spore predator (Mycodiplosis hemileiae). Here we report on comparative surveys of the CLR and its two natural enemies in Mexico, where the CLR has been at epidemic status since 2012, and Puerto Rico, where the CLR is present but has not reached epidemic densities. We found that the densities of the two control agents per CLR lesion is higher in Puerto Rico than in Mexico, and we hypothesize that their joint presence at higher densities is contributing to the suppression of the CLR in Puerto Rico but not in Mexico. Furthermore, we found that the presence of Azteca sericeasur, a keystone ant species that occurs in Mexico but not Puerto Rico, significantly reduces the prevalence of M. hemileiae on coffee plants. Our work provides data that allows us to hypothesize that the joint presence of these two control agents may potentially provide control of the CLR and also highlights the importance of regionally specific communities within agroecosystems, and how variation in community composition may lead to varying outcomes for biological control. Additionally, this is the first report of the presence of a potentially important biological control agent, M. hemileiae, in Latin America and the Caribbean.

We identified 41 species of native bees from a total of 1,083 specimens collected at cultivated highbush blueberry plantings throughout Rhode Island in 2014 and 2015. Andrena spp., Bombus spp., and Xylocopa virginica (L.) were collected most often. Bombus griseocollis (DeGeer), B. impatiens Cresson, B. bimaculatus Cresson, B. perplexus Cresson, and Andrena vicina Smith collected the largest mean numbers of blueberry pollen tetrads. The largest mean percent blueberry pollen loads were carried by the miner bees Andrena bradleyi Viereck (91%), A. carolina Viereck (90%), and Colletes validus Cresson (87%). The largest mean total pollen grain loads were carried by B. griseocollis (549,844), B. impatiens (389,558), X. virginica (233,500), and B. bimaculatus (193,132). Xylocopa virginica was the fourth and fifth most commonly collected bee species in 2014 and 2015, respectively. They exhibit nectar robbing and females carried relatively low blueberry pollen loads (mean 33%). Overall, we found 10 species of bees to be the primary pollinators of blueberries in Rhode Island.

We conducted a survey to examine parasitism, predation, and the species composition of native parasitoids attacking sentinel egg masses of the invasive pest, the brown marmorated stink bug, Halyomorpha halys (Stål), in bell pepper, squash, and tomato. A 2-yr survey was conducted for each crop. The species composition of parasitoids was determined for parasitoids that successfully emerged from eggs, parasitoids that were identified from dissections, and parasitoids that were found attending egg masses at the time of collection. The overall rate of brown marmorated stink bug nymphal emergence was 82.7% from laboratory-reared control egg masses compared with only 23.4% from sentinel egg masses due to a combination of predation, parasitism, and unknown mortality causes. Overall, 12.4% of sentinel eggs were parasitized. Parasitoids emerged successfully from only 2.3% of eggs, but they were dissected from an additional 10.1% of eggs. Telenomus podisi Ashmead was the predominant species identified from emerged parasitoids (57.4%), dissected parasitoids (90.2%), and parasitoids attending egg masses (77%). This study provides further evidence that the impact of native parasitoids on brown marmorated stink bug egg mortality may be greatly underestimated based solely on parasitoid emergence rates alone.

The eastern cherry fruit fly, Rhagoletis cingulata Loew (Diptera: Tephritidae), is an economically important pest of cherries in North America. In 1983 it was first reported in Europe where it shares its ecological niche with the native European cherry fruit fly, Rhagoletis cerasi L. (Diptera: Tephritidae). Their coexistence in Europe led to the recent horizontal transmission of the Wolbachia strain wCer1 from R. cerasi to R. cingulata. Horizontal Wolbachia transmission is mediated by either sharing of ecological niches or by interacting species such as parasitoids. Here we describe for the first time that two braconid wasps, Psyttalia rhagoleticola Sachtleben (Hymenoptera: Braconidae) and Utetes magnus Fischer (Hymenoptera: Braconidae), naturally parasitizing R. cerasi, use the invasive R. cingulata in Europe as a new host. In contrast, no parasitoids that parasitize R. cingulata in its native American range were detected in the introduced European range. Diagnostic Wolbachia PCR screening and sequence analyses demonstrated that all P. rhagoleticola individuals were infected with the newly described Wolbachia strain wRha while all U. magnus individuals were uninfected. wRha is different from wCer1 but had an Wolbachia surface protein (wsp) gene sequence that was identical to wCer2 of R. cerasi and wCin2 of R. cingulata. However, multi locus sequence typing revealed differences in all loci between wRha and the tephritid's strains. The horizontal transmission of wCer1 between the two tephritid species did not result in fixed heritable infections in the parasitoids. However, the parasitoids may have acted as a transient wCer1 vector.

The rice stem stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is a primary insect pest of paddy rice in South America. Knowledge of its spatial distribution can support sampling plans needed for timely decisions about pest control. This study aimed to investigate the spatial distribution of adults and nymphs of T. limbativentris and determine the spatial coexistence of these stages of development. Fifteen paddy rice fields were scouted once each season to estimate insect densities. Scouting was performed on regular grids with sampling points separated by ∼50 m. Moran's I and semivariograms were used to determine spatial distribution patterns. Spatial coexistence of nymphs and adults was explored via spatial point process. Here, adults and nymphs had typically contrasting spatial distribution patterns within the same field; however, the frequency of aggregation was not different between these developmental stages. Adults and nymphs were aggregated in seven fields and randomly distributed in the other eight fields. Uniform distribution of adults or nymphs was not observed. The study-wide semivariogram ranges were ∼40 m for adults and ∼55 m for nymphs. Nymphs and adults spatially coexisted on 67% of the fields. Coexisting patterns were classified using one of the following processes: stage-independent, bidirectional attractive, unidirectional attractive, bidirectional inhibiting, or unidirectional inhibiting. The information presented herein can be important for developing sampling plans for decision-making, implementing tactics for site-specific management, and monitoring areas free of T. limbativentris.

Three main hypotheses have been postulated over the past century to explain the outbreaking population dynamics of eastern spruce budworm, Choristoneura fumiferana (Clemens). The Silviculture Hypothesis first arose in the 1920s, with the idea that outbreaks were driven by forestry practices favoring susceptible softwood species. In the 1960s, it was proposed that populations were governed by Multiple Equilibria, with warm weather conditions releasing low-density populations from the regulatory control of natural enemies. Dispersal from outbreak foci, or “epicenters,” was seen as causing widespread outbreaks that eventually collapsed following resource depletion. However, in the 1980s, following the re-analysis of data from the 1940s outbreak in New Brunswick, this interpretation was challenged. The alternative Oscillatory Hypothesis proposed that budworm population dynamics were governed by a second-order density-dependent process, with oscillations being driven by natural enemy–victim interactions. Under this hypothesis, weather and resource availability contribute to secondary fluctuations around the main oscillation, and weather and moth dispersal serve to synchronize population cycles regionally. Intensive, independent population studies during the peak and declining phases of the 1980s outbreak supported the principal tenet of the Oscillatory Hypothesis, but concluded that host plant quality played a more important role than this hypothesis proposed. More recent research on the early phase of spruce budworm cycles suggests that mate-finding and natural-enemy-driven Allee effects in low-density populations might be overcome by immigration of moths, which can facilitate the onset of outbreaks. Even more recent research has supported components of all three hypotheses attempting to explain spruce budworm dynamics. In the midst of a new rising outbreak (2006-present), we discuss the evolution of debates surrounding these hypotheses from a historic perspective, examine gaps in current knowledge, and suggest avenues for future research (e.g., intensive studies on low-density populations) to better understand and manage spruce budworm populations.

Wheat stem sawfly (Cephus cinctus Norton, Hymenoptera: Cephidae) has long been a significant insect pest of spring, and more recently, winter wheat in the northern Great Plains. Wheat stem sawfly was first observed infesting winter wheat in Colorado in 2010 and, subsequently, has spread rapidly throughout wheat production regions of the state. Here, we used maximum entropy modeling (MaxEnt) to generate habitat suitability maps in order to predict the risk of crop damage as this species spreads throughout the winter wheat-growing regions of Colorado. We identified environmental variables that influence the current distribution of wheat stem sawfly in the state and evaluated whether remotely sensed variables improved model performance. We used presence localities of C. cinctus and climatic, topographic, soils, and normalized difference vegetation index and enhanced vegetation index data derived from Moderate Resolution Imaging Spectroradiometer (MODIS) imagery as environmental variables. All models had high performance in that they were successful in predicting suitable habitat for C. cinctus in its current distribution in eastern Colorado. The enhanced vegetation index for the month of April improved model performance and was identified as a top contributor to MaxEnt model. Soil clay percent at 0–5 cm, temperature seasonality, and precipitation seasonality were also associated with C. cinctus distribution in Colorado. The improved model performance resulting from integrating vegetation indices in our study demonstrates the ability of remote sensing technologies to enhance species distribution modeling. These risk maps generated can assist managers in planning control measures for current infestations and assess the future risk of C. cinctus establishment in currently uninfested regions.

Insect populations are affected by density-dependent and density-independent factors, and knowing how these factors affect long-term population growth is critical to pest management. In this study, we experimentally manipulated densities of the hemlock woolly adelgid on eastern and western hemlock trees in the western USA to evaluate the effects of density and host species on hemlock woolly adelgid crawler colonization. We then followed development of hemlock woolly adelgid on each hemlock species. Settlement of crawlers was strongly density-dependent and consistent between host species. In addition, a period of hot days that coincided with the settlement of hemlock woolly adelgid crawlers put our experimental and naturally occurring populations into diapause during April. Diapause resulted in one generation that yr in our experimental population. Analyses of long-term air temperature records indicated that diapause-inducing temperatures in April similar to those observed in our experiment have occurred rarely since 1909 and the frequency of these events has not changed over time. Prior work suggests that hemlock woolly adelgid completes two generations per yr in the western USA with a diapause occurring in the summer. This typical life history reflects the long-term influence of regional average seasonal temperature patterns on development and the timing of diapause-inducing temperatures. However, the timing of unseasonal weather, such as the hot days observed in our experiment, occasionally changes life history trajectories from this normal pattern. Our results show that density-dependent and density-independent factors have strong effects on generational mortality and life history of hemlock woolly adelgid that are important to its population dynamics and management.

Efforts to manage and eradicate invasive species can benefit from an improved understanding of the physiology, biology, and behavior of the target species, and ongoing efforts to eradicate the Asian longhorned beetle (Anoplophora glabripennis Motschulsky) highlight the roles this information may play. Here, we present a climate-driven phenology model for A. glabripennis that provides simulated life-tables for populations of individual beetles under variable climatic conditions that takes into account the variable number of instars beetles may undergo as larvae. Phenology parameters in the model are based on a synthesis of published data and studies of A. glabripennis, and the model output was evaluated using a laboratory-reared population maintained under varying temperatures mimicking those typical of Central Park in New York City. The model was stable under variations in population size, simulation length, and the Julian dates used to initiate individual beetles within the population. Comparison of model results with previously published field-based phenology studies in native and invasive populations indicates both this new phenology model, and the previously published heating-degree-day model show good agreement in the prediction of the beginning of the flight season for adults. However, the phenology model described here avoids underpredicting the cumulative emergence of adults through the season, in addition to providing tables of life stages and estimations of voltinism for local populations. This information can play a key role in evaluating risk by predicting the potential for population growth, and may facilitate the optimization of management and eradication efforts.

From 2010 through 2013, adult emergence and seasonality of Laricobius nigrinus Fender, an introduced predatory species native to western North America, as well as hybridization with the native species Laricobius rubidus (LeConte), were evaluated using emergence traps and beat-sheet sampling in areas of previous release against hemlock woolly adelgid, Adelges tsugae Annand. The shortest emergence period of adult L. nigrinus was 7 wk beginning 22 October 2010, and the longest emergence was 15 wk beginning 17 October 2012. Native L. rubidus also were collected from emergence traps placed on the ground surface and beat-sheet samples all 3 yr, with emergence of L. rubidus initiating later than L. nigrinus each season. Seasonality of both Laricobius species was similar across a 44-mo study period. Adult L. nigrinus were present from October through April, and larvae of Laricobius spp. were collected from February to May. The average number of L. nigrinus from emergence traps was significantly greater than the average number of beetles collected from beat-sheet samples in 2010, while the converse was observed during 2012. Hybridization between L. nigrinus and L. rubidus was documented from 10.75% of specimens collected during 2010 and 2011, indicating periodic interbreeding between the introduced and native species. These findings suggest emergence trapping may be a useful method to assess establishment, population densities, and seasonality of Laricobius species in areas of release to enhance their use in management of A. tsuage.

The brown widow spider, Latrodectus geometricus C. L. Koch, 1841, is a large spider of the family Theridiidae that belongs to a genus of medical interest owing to its potent neurotoxic venom, which causes severe pain in humans. In America, this alien spider has been found in virtually all countries in the region, mainly associated with human dwellings, but also in agricultural sectors. However, the invasive process and potential distribution of this invasive species across the American continent are completely unknown. In this context, using a combination of both global and regional niche models, it is possible to hypothesize the invasive phase of the species as well as the geographic space where these different phases occur. By comparing the global and regional niches of L. geometricus, we examined its invasive process and potential distribution across the American continent. This work is an innovative approach to understanding the invasion of the brown widow spider in this area and the ecological processes that underlie this invasion. In this context, the global and regional niche comparison constitutes an appropriate tool to account for the complexities of the invasive process, generating different hypotheses amenable to being tested in future studies.

Bees and flies are the main pollinators responsible for the maintenance of plant diversity and crop production. Studies of pollinator communities have focused on bees; however, community structures may vary among groups of pollinators. We describe and compare the diversity and resource use patterns of six Apoidea and two Diptera anthophile families in Cuatro Ciénegas in the northeast of Mexico. We sampled insects in two distinct geographic units (valley and mountains) and two seasons (rainy and dry). Spatial and temporal patterns in species composition and abundance of these families were identified and the diversity in each family compared. The spatial and temporal patterns in species composition, diversity, and resource use were different for each family. Overall, diversity was higher during the rainy season. Only fly families and the Andrenidae presented season-specific differences in species composition, in contrast with the other Apoidea. Two bee families visited more plant species per insect species during the rainy season, whereas flies visited the same number of plant species in both seasons. Apidae, Megachilidae, and Bombyliidae visited more plant species in the mountains, while the other families exhibited no differences between the mountains and the valley. The variation in the community structures of each group may reflect distinct life histories, resources needs during larval stages, and foraging behaviors. These differences are relevant in management and conservation programs that could benefit one group of pollinators while harming others with different characteristics. The traits of some families indicate their potential value as pollinators.

Nonconsumptive effects of predators on prey are well known, but similar effects among competing predators are not. Aphidophagous insect larvae are notorious for cannibalism and intraguild predation, as they compete for aggregated but ephemeral prey. We tested for indirect effects of competitors on the development of Coleomegilla maculata DeGeer and Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae), and a green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), with all larvae reared on eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Control larvae were reared singly, while treatment larvae were reared pairwise, with either a conspecific or heterospecific, in partitioned Petri dishes that allowed the passage of chemical cues. Larvae of C. maculata, a dietary generalist, appeared stressed by the presence of competing larvae, whether con- or heterospecific, and suffered fitness costs (longer pupation times, lower male adult mass). In contrast, H. convergens and C. carnea, both aphid specialists, responded to competing larvae with accelerated development, and without any apparent costs in terms of adult size or reproductive performance. Adult C. carnea in some treatments were heavier than solitary controls, suggesting a higher consumption rate by the induced phenotype, and those exposed to H. convergens began oviposition earlier. Thus, the phenotypes induced in the specialized aphid predators were adaptive for development in aphid colonies, whereas that induced in the generalist was not. These results indicate that nonconsumptive effects are not simply a vertical force acting on prey, but can also impact conspecific and heterospecific competitors on the same trophic level.

We describe the spatial variation in the structure and composition of the communities of insects visiting the inflorescences of Flaveria ramosissima Klatt, Florestina pedata (Cav.) Cass., and Parthenium bipinnatifidum (Ort.) Rollins (Asteraceae) in a xeric environment in Central Mexico. Inflorescences of the three Asteraceae were visited by a total of 96 species of Hymenoptera, Diptera, Lepidoptera, Coleoptera, and Hemiptera. Total species richness of floral visitors to the three Asteraceae and total abundance of insects of Fl. pedata and P. bipinnatifidum did not differ between low and high vegetation cover sites. Total abundance of insects visiting the inflorescences of F. ramosissima and abundance of Hymenoptera in all three Asteraceae were higher at the low vegetation coverage (LVC) site than at the high vegetation coverage (HVC) one. Diversity of insects of Fl. pedata and P. bipinnatifidum was higher at the HVC site. However, in F. ramosissima diversity was higher at the LVC site. The communities of insects of each Asteraceae were dissimilar between sites. These differences can be attributed to variation in the abundance of Lepidophora (Diptera: Bombyliidae), Miridae (Hemiptera), Melyridae (Coleoptera), Tiphiidae (Hymenoptera), Myrmecocystus mexicanus Wesmael, and Dorymyrmex grandulus (Forel) (Hymenoptera: Formicidae). The first three insect groups were sensitive to LVC, high temperature, and low humidity, whereas the last three tolerated those same environmental conditions. Changes in temperature, humidity, and resources associated with vegetation coverage seem to differentially affect each species of floral visitors of the three Asteraceae species studied.

Subterranean termites need to minimize potentially pathogenic and competitive fungi in their environment in order to maintain colony health. We examined the ability of Actinobacteria isolated from termite guts in suppressing microorganisms commonly encountered in a subterranean environment. Guts from two subterranean termite species, Reticulitermes flavipes (Kollar) and Reticulitermes tibialis Banks, were extracted and plated on selective chitin media. A total of 38 Actinobacteria isolates were selected for in vitro growth inhibition assays. Target microbes included three strains of Serratia marcescens Bizio, two mold fungi (Trichoderma sp. and Metarhizium sp.), a yeast fungus (Candida albicans (C.P. Robin) Berkhout), and four basidiomycete fungi (Gloeophyllum trabeum (Persoon) Murrill, Tyromyces palustris (Berkeley & M.A. Curtis) Murrill, Irpex lacteus (Fries) Fries, and Trametes versicolor (L.) Lloyd). Results showed both broad and narrow ranges of antimicrobial activity against the mold fungi, yeast fungus, and S. marcescens isolates by the Actinobacteria selected. This suggests that termite gut-associated Actinobacteria produce secondary antimicrobial compounds that may be important for pathogen inhibition in termites. Basidiomycete fungi were strongly inhibited by the selected Actinobacteria isolates, with G. trabeum and T. versicolor being most inhibited, followed by I. lacteus and T. palustris. The degree of inhibition was correlated with shifts in pH caused by the Actinobacteria. Nearly all Actinobacteria isolates raised pH of the growth medium to basic levels (i.e. pH ∼8.0–9.5). We summarize antimicrobial activity of these termite gut-associated Actinobacteria and examine the implications of these pH shifts.

The rice water weevil, Lissorhoptrus oryzophilus Kuschel, is the most important insect pest of rice in the United States. Management of L. oryzophilus mainly depends upon the use of insecticides due to the lack of effective alternative management tactics. A 3-yr field study was conducted to determine if difference exists among rice genotypes and cultivars of inbred tropical japonica subspecies commercially grown in the southern United States [Cocodrie (PI 606331), CL171, and CL151 (PI 654463)] and the germplasm lines of indica subspecies adapted to tropical climates of Asia [WC 4644 (PI 312777), TNI (PI 495830), Rondo (PI 615022), 4612 (PI 615039), TeQing (PI 536047), and 4593 (PI 615031)] for resistance to L. oryzophilus. Experiments were established as a split-plot design with cultivars as main plots and insecticide treatment as subplots. No significant differences were observed in number of L. oryzophilus larvae recovered across cultivars and genotypes, indicating no significant variation in their preference to L. oryzophilus oviposition. Insecticide treatment had a significant impact on L. oryzophilus larval density. However, grain yield did not vary significantly between treated and untreated plots for any of the cultivars and genotypes. The amount of yield loss in response to L. oryzophilus infestation did not vary significantly across genotypes and cultivars, indicating no variation among these genotypes for resistance to L. oryzophilus.

Potato virus Y (PVY) is a major concern for potato production in the United States given its impact on both crop quality and yield. Although green peach aphid, Myzus persicae (Sulzer), is the most efficient PVY vector, it may be less abundant in potato-growing areas of Idaho relative to non-potato-colonizing aphid vectors of PVY that may disperse from nearby cereal fields and other crops. A field study was conducted during 2012–2013 to examine if noncolonizing aphids disperse to nearby potato fields as cereal crops dry down before harvest. The aphid fauna was sampled weekly in four different potato fields in south-central and southeastern Idaho using yellow sticky traps and yellow pan traps. Potato fields were chosen with an adjacent cereal field such that the prevailing westerly wind would facilitate aphid dispersal from cereal fields to potato. Non-potato-colonizing aphids sampled included 10 cereal aphid species, the most abundant of which were Rhopalosiphum padi L. and Metopolophium dirhodum (Walker). More than 35 species from noncereal hosts also were found. Overall, green peach aphid abundance was relatively low, ranging from 0.5–2.5% of the total aphid capture between years and among fields. In both years and all locations, cereal aphid abundance peaked in mid- to late July (cereal ripening stage) and decreased thereafter as cereal crops dried. PVY prevalence in the potato fields increased following these increases in aphid abundance. This study suggests that cereal aphids and other noncolonizing aphids are important contributors to PVY prevalence in potato in southern Idaho.

Recent outbreaks of forest insects have been directly linked to climate change-induced warming and drought, but effects of tree stored resources on insects have received less attention. We asked whether tree stored resources changed following mountain pine beetle (Dendroctonus ponderosae Hopkins) attack and whether they affected beetle development. We compared initial concentrations of stored resources in the sapwood of whitebark pine (Pinus albicaulis Engelmann) and lodgepole pine (Pinus contorta Douglas ex. Louden) with resource concentrations one year later, in trees that were naturally attacked by beetles and trees that remained unattacked. Beetles did not select host trees based on sapwood resources—there were no consistent a priori differences between attacked versus unattacked trees—but concentrations of nonstructural carbohydrate (NSC), lipids, and phosphorus declined in attacked trees, relative to initial concentrations and unattacked trees. Whitebark pine experienced greater resource declines than lodgepole pine; however, sapwood resources were not correlated with beetle success in either species. Experimental manipulation confirmed that the negative effect of beetles on sapwood and phloem NSC was not due to girdling. Instead, changes in sapwood resources were related to the percentage of sapwood with fungal blue-stain. Overall, mountain pine beetle attack affected sapwood resources, but sapwood resources did not contribute directly to beetle success; instead, sapwood resources may support colonization by beetle-vectored fungi that potentially accelerate tree mortality. Closer attention to stored resource dynamics will improve our understanding of the interaction between mountain pine beetles, fungi, and host trees, an issue that is relevant to our understanding of insect range expansion under climate change.

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is an invasive pest in North America and Europe that attacks soft-skinned ripening fruit such as raspberries, blackberries, and blueberries. Little is known regarding the specific cues D. suzukii utilizes to locate and select host fruit, and inconsistencies in trap performance indicate the need for the development of improved monitoring and management techniques for this insect. Our studies focused on identifying attractive visual cues for adult D. suzukii and incorporating these cues into a potential attract-and-kill tactic for D. suzukii management. We evaluated D. suzukii response to color, shape, and size-specific stimuli. For color, we evaluated 10.2-cm-diameter spheres painted black, red, purple, orange, green, yellow, blue, or white. Shape stimuli (254 cm³ surface area) included sphere, cube, pyramid, inverted pyramid, vertical or horizontal cylinder and were painted red. Size stimuli included red 2.5-, 10.2-, 15.2-, and 25.4-cm-diame-ter spheres. Trials were conducted under laboratory, semifield, and field conditions. For color, adults preferred black and red spheres to all other colors evaluated. Among shapes, there was no significant preference. For size, larger spheres captured significantly more D. suzukii compared with a small 2.5-cm-diameter sphere. Determining D. suzukii visual preference will aid in trapping and behaviorally based management programs.

Cues from emergence sites may be predictive of mating opportunities if potential mates are slow to disperse after emergence, and particularly if emergence sites are clumped, as in the solitary parasitoid wasp Urolepis rufipes Ashmead. Males emerge before females, and the present study suggests that males may use emergence sites of conspecific males to locate mates. In choice experiments, virgin males spent more time on a male-emerged host (a host from which a male had recently emerged) than on a female-emerged host. Relative to when no host was present, virgin males also marked more in the presence of a male-emerged host, but did not mark more in the presence of a female-emerged host. Females, but not other males, are known to be attracted to male marks. Unlike for males, there was no evidence that females distinguished between male-emerged and female-emerged hosts. Virgin females preferred areas where multiple males had marked over areas where a single male had marked. Such areas had more total marks, yet marks per male did not differ between aggregated and solitary males. Thus, through his own attraction to male-emerged hosts and by marking near other males a male may find and attract females, and with no apparent increase in the cost of attraction.

Behaviors and mortality of two filth fly parasitoid wasps, Spalangia endius Walker and Urolepis rufipes Ashmead, were tested in response to granular fly baits containing one of the three active ingredients (AI): Golden Malrin (methomyl), QuickBayt (imidacloprid), or Quikstrike (dinotefuran). Behavioral responses to each of the two components of the baits, the AIs and the fly attractant pheromone (Z)-9-tricosene, were also examined independently. Spalangia endius avoided contact with bait granules, regardless of bait type. However, when S. endius contacted bait residue, the imidacloprid bait appeared to be the least harmful of the baits for S. endius, at least in the short term. Spalangia endius was attracted to imidacloprid by itself. However, S. endius avoided (Z)-9-tricosene. In contrast to S. endius’ attraction to imidacloprid, S. endius neither avoided nor was attracted to methomyl or dinotefuran. For U. rufipes, the methomyl bait appeared to be especially harmful. Urolepis rufipes avoided bait granules with imidacloprid or dinotefuran but not with methomyl, died quickly in the presence of methomyl bait residue, and had a methomyl LC₅₀ that was lower than that for S. endius. The avoidance by U. rufipes of granules with imidacloprid or dinotefuran appears to be related to components other than the AIs or the (Z)-9-tricosene because U. rufipes did not avoid either individually. The behavioral avoidance of the parasitoids in the present study occurred despite no exposure recently, if ever, to these pesticides.

Sirex nigricornis F. (Hymenoptera: Siricidae) is an innocuous pine-inhabiting woodwasp native to eastern North America, utilizing dead or dying pine trees as hosts. Although S. nigricornis F. does not cause economic damage, a closely related species, Sirex noctilio, was discovered in New York in 2004 and has continually spread throughout the northeastern United States and southern Canada, threatening the multi-billion-dollar pine timber industry of the southeastern United States and raising interest about potential interactions with native woodwasps and associated mortality agents. A non-sterilizing strain of the biological control agent, Deladenus siricidicola Bedding (Tylenchida: Neotylenchidae), was introduced along with S. noctilio but is not inhibiting the spread or establishment of S. noctilio. A North American congener, Deladenus proximus Bedding, has been recently isolated from S. noctilio and shows promise as a biological control agent. To better understand the potential of D. proximus as a control agent for S. noctilio, we measured and dissected nearly 1,200 S. nigricornis females from Arkansas and Mississippi and evaluated differences among collection location with regard to nematode virulence, woodwasp body size, and egg load. Body size and egg load were related to collection location, and nematode infestation resulted in significantly smaller females who produced significantly fewer eggs. Female woodwasps, especially those collected in Arkansas, were often fully sterilized by nematodes, and a higher percent sterilization was inversely related to body size and fewer eggs. We propose field studies to test the nematode's ability to sterilize S. noctilio in the northeastern United States.

The hemlock woolly adelgid, Adelges tsugae Annand, is an invasive pest of eastern (Tsuga canadensis (L.) Carrière) and Carolina hemlock (Tsuga caroliniana Engelmann) forests in the eastern United States. Scymnus (Pullus) coniferarum Crotch (Coleoptera: Coccinellidae) is a lady beetle that preys on A. tsugae in the western United States, where A. tsugae infestations on western hemlocks are not lethal. It is thought that S. coniferarum could be an important predator that helps keep A. tsugae populations from reaching damaging levels in this region. This study assesses the potential of this predator as a biological control agent for A. tsugae in the eastern United States. S. coniferarum predation, reproductive potential, and survival were evaluated in field-cages on adelgid-infested T. canadensis at two sites in southwestern Virginia. Sampling was conducted between December 2012 and June 2014 to evaluate the impact of S. coniferarum on both generations of A. tsuage (sistens and progrediens). Adult S. coniferarum fed on both generations and all life stages of A. tsugae during both field trials at rates comparable to other adelgid-specific predators. Evidence of S. coniferarum oviposition was minimal, and may be attributed to low temperatures and prey availability. S. coniferarum mortality was greatest when exposed to winter temperatures at the higher elevation site in 2013, and least throughout the 2014 spring sample period. S. coniferarum demonstrated a high predation rate on A. tsugae and survived for extended periods of time at sites in southwest Virginia, indicating that this species could be an effective predator of hemlock woolly adelgid in similar climates.

Conservation tillage combined with cover crops or mulching may enhance natural enemy activity in agroecosystems by reducing soil disturbance and increasing habitat structural complexity. In particular, weed seed predation can increase with vegetation cover and reduced tillage, indicating that mulches may improve the quality of the habitat for weed seed foraging. The purpose of this study was to quantify the effects of tillage and mulching for conservation biological control in cucurbit fields. The effects of mulch and reduced tillage on arthropods and rates of weed seed loss from arenas were examined in field trials on sandy soils in 2014 and 2015. Experimental factors included tillage and cover crop, each with two levels: strip-tillage or full-tillage, and cover crop mulch (rye residue) or no cover crop mulch (unmulched). Arthropod abundance on the crop foliage was not affected by tillage or cover crops. Contrary to expectations, epigeal natural enemies of insects and rates of weed seed removal either did not respond to treatments or were greater in full-tilled plots and plots without mulch. Our study demonstrates the potential importance of weed seed predators in reducing weed seedbanks in vegetable agroecosystems, and suggests that early-season tillage may not be detrimental to epigeal predator assemblages.

After injury many insects could regenerate lost limb. In this study, Helicoverpa armigera Hubner and Locusta migratoria manilensis (Meyen, 1835) were chosen to compare the regeneration potency of holometabolous and hemimetabolous insects. We employed the classical approach of surgical excision to verify the regeneration ability and to investigate the factors that affect the extent of regeneration. The results found that H. armigera could regenerate intact legs when the larval legs were excised at the first and second instar and that legs of adult H. armigera had a close relationship with their larval counterparts. However, the adult legs became malformed or disappeared when excised at other older instars. For the L. migratoria, we found the legs have weak partial regeneration ability when amputation was conducted at the joint of two segments. The regeneration potency might be stronger the more proximal the operation. Regeneration process had a negative impact on the larval development. This is the first report of complete leg regeneration capacity having a strong correlation with the instar but not with the position where amputation occurred for H. armigera, while for the L. migratoria, partial regenerative ability had a close relationship with the position where amputation occurred but not with instars.

The ability to predict key phenological events, such as the timing of flight periods, is useful for the monitoring and management of insect pests. We used empirical data to describe the flight period of mountain pine beetle, Dendroctonus ponderosae Hopkins, in its recently expanded range east of the Rocky Mountains in Canada and developed a degree-day model based on the number of trapped beetles. Data were collected over four degrees of latitude and six years. The main flight period, when the middle 70% of the total number of beetles were caught, started during the second or third week of July, lasted 26 d, and peaked within 2 wk of starting. The best model accounted for 89% of the variation in the data. Mountain pine beetle's flight tended to start later and be more contracted at higher latitudes. The synchrony of mountain pine beetle's flight period in the expanded range appears to be comparable to the limited reports from the historic range, although it may start earlier. This suggests that conditions in the new range are suitable for a coordinated dispersal flight, which is critical for the beetle's strategy of overwhelming tree defenses by attacking en masse. Forest managers can use the model to support operational decisions, e.g., when to impose hauling restrictions to reduce the risk of spread through the transport of infested material, or the time frame for control programs. Understanding the flight period may also improve our ability to assess the response of mountain pine beetle to novel and changing climates in the future.

Adult females of the two-spotted spider mite (Tetranychus urticae Koch) enter diapause under conditions of short-day length and low temperature. A conspicuous body color change, from greenish yellow to bright orange, accompanies diapause induction. This pigmentation is attributed to accumulation of keto-carotenoids produced internally from β-carotene, which is a precursor of vitamin A essential for inducing diapause. The quantity of β-carotene transferred from females to eggs has been considered sufficient to induce diapause. Moreover, carotenoid biosynthesis genes were recently found in this mite. Therefore, imaginal feeding is not likely to be necessary to progress to diapause. In contrast, diapause-induced adult females have been known to feed between the last molt and the time of body color changes. Consequently, the function of imaginal feeding in diapause-induced females was largely unknown. We aimed to clarify whether imaginal feeding was essential to enter diapause. First, we verified that body color change occurred in connection with the feeding behavior, and also verified the change in the composition of carotenoids in diapausing females. Subsequently, we tested the effects of restraints on feeding after molting on carotenoid composition and diapausing rates. Body color change required imaginal feeding. Fed, but not unfed, females accumulated astaxanthin. Moreover, starvation reduced diapausing rates. We concluded that imaginal feeding between the last molt and the time of body color change was necessary to progress to the diapausing phenotype and that starvation at the adult stage reduced the percentage of adults entering reproductive diapause.

Environmental stress can lead to a decrease in the body size of insects. As social insects, ants have a complex caste system; each caste has its own morphological traits and functions in the colony, hence the effects of stress may manifest differentially among different ant castes. Here we investigated the body size of males of the common garden ant, Lasius niger L., 1758, living in a postmining area polluted mainly by Zn, Cd, and Pb. We examined if individual body size decreases with the pollution gradient. The ants were sampled from 39 wild colonies originating from 17 sites located along the metal pollution gradient; head width was used as the estimator of body size. We failed to show a significant correlation between pollution and male body size, indicating no direct effect of pollution on the body size of males of the investigated ant. However, we found a significant dependence with the colony of origin, which is in line with a previous study performed on this species in unpolluted sites. These results further strengthen a general conclusion that morphological traits in ants, such as body size or fluctuating asymmetry, are relatively invariable and stable across gradients of metal pollution.