Both maize and cotton genetically engineered to express Bt toxins are widely planted and important pest management tools in the United States. Recently, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) has developed resistance to two toxin Bt maize and cotton (Cry1A and Cry2A). Hence, growers are transitioning to three toxin Bt cotton and maize that express both Cry toxins and the Vip3Aa toxin. H. zea susceptibility to Vip3Aa is threatened by 1) a lack of availability of non-Bt refuge crop hosts, including a 1–5% annual decline in the number of non-Bt maize hybrids being marketed; 2) the ineffectiveness of three toxin cultivars to function as pyramids in some regions, with resistance to two out of three toxins in the pyramid; and 3) the lack of a high dose Vip3Aa event in cotton and maize. We propose that data should be collected on current Cry-resistant H. zea in the field to inform future Bt resistance models and that the deployment of Bt toxins and non-Bt refuge crops should be adjusted to favor susceptibility of H. zea to Bt toxins such as Vip3Aa. Finally, maize growers should be incentivized to plant non-Bt structured refuge and have access to hybrids with high-yielding genetic potential at a reasonable price.

Drosophila suzukii (Matsumura) is an invasive pest of soft-skinned fruits that has caused significant economic damage worldwide. In this study, we focused on the seasonal abundance of D. suzukii during the early years of establishment in Wisconsin. We explored the seasonal patterns of summer and winter morphs, their reproductive output, and the effect temperature and humidity may have on their seasonal phenology. The seasonal abundance of D. suzukii during 2 yr (2014–2015) revealed that flies were detected in Wisconsin from early July to late December, with winter morphs being trapped from August through December. The adult populations trapped spanned 1 mo longer in 2015 than in 2014. The peak proportional abundance of D. suzukii in 2015 was recorded in August which was about 2 mo earlier than that in 2014. The combined factor [maximum temperature and maximum humidity] explained the most amount of variation in D. suzukii abundance consistently across the 2 yr in Wisconsin. We did not find significant differences in the fat content, number of mature eggs, proportion of females with immature eggs, or proportion of mated females between summer morph females at the beginning, summer and winter morph females during the middle, or winter morph females at the end of the collecting season in 2015. Our results build on the body of work providing a better understanding of the D. suzukii–overwintering abilities and strengthen the importance of early crop risk assessment and targeted control strategies.

The study of diversity gradients is a frequent approach to understand evolutionary processes that structure communities. Altitudinal gradients allow the analysis of community spatial responses to environmental fluctuations. One interesting place to study altitudinal gradients is the Andes system because of the coexistence of isolated and continuous mountain ranges. We investigated the altitudinal turnover of species in peripheral mountainous systems by analyzing the structure of dung beetle assemblages along a complete gradient in the Sierra Nevada de Santa Marta, Colombia. Seven sites ranging from 480 to 2,890 m were evaluated, using linear transects of pitfall traps. A total of 2,992 individuals and 46 species were collected. Abundance, richness, and diversity diminished with altitude, revealing significant differences among sites. Some genera appeared at certain altitudes and most species appeared at unique sites, indicating a marked altitudinal turnover. A similarity analysis demonstrated the existence of separate lowland and high mountain groups with a turnover at 1,200–1,600 m asl. We registered for the first time a species replacement between Scarabaeinae (low-lands) and Aphodiinae (high-lands) in the Neotropical region. Our results largely agree with the species pattern described for Mesoamerica, although, in this case the altitudinal turnover is more evident, unveiling a transition zone between lowland and high mountain fauna elements. This result suggests an equilibrium between a weak horizontal colonization and a strong vertical turnover, that appears to be higher in isolated mountains. Future investigations with other insect groups are necessary to corroborate this altitudinal pattern in isolated mountains.

Termites and fungi are the primary decomposers of dead wood. Interactions between wood-feeding termites and wood-rot fungi are inevitable given their shared food source. Termites have developed multiple defense strategies against infectious fungi, such as Metarhizium spp., that include antifungal proteins in their saliva and fungal inhibition properties in their gut. The antifungal properties of termite salivary secretions depend on β-1,3-glucanases that are likely to be effective against a broad spectrum of filamentous fungi. Given the overlap in niches, there is opportunity for interference competition between termites and wood-rot fungi to occur. Here we demonstrate that β-1,3-glucanases in the saliva and the antifungal properties of the gut of the eastern subterranean termite Reticulitermes flavipes (Kollar) (Blattodea: Rhinotermitidae) affects the growth of two common wood-rot fungi, Gloeophyllum trabeum Persoon (Murrill) (Gloeophyllales: Gloeophyllaceae) and Phanerochaete chrysosporium (Burdsall) (Polyporales: Phanerochaetaceae).

The use of soil and litter arthropods as biological indicators is a way to assess environmental changes, where ant species in particular may serve as important indicators of soil quality. This study aimed at relating the abundance of soil and litter ant species to soil parameters under different tree species, both native and exotic, and varieties of coffee and banana plantations. Variations were found in soil physicochemical parameters. A total of 30 species belonging to 14 genera, and four subfamilies, the Formicinae, Dorylinae, Myrmicinae, and Ponerinae were identified. Higher abundance was found in coffee plantations compared to banana plantations, exotic and native tree species. Species of Camponotus cinctellus and Odontomachus troglodytes occurred in all land uses which is a sign of tolerance to a wide range of soil properties. In addition, these species, together with Myrmicaria SP02, Phrynoponera gabonensis, Camponotus SP06, Myrmicaria opaciventris, Pheidole SP03, Tetramorium simillimum, Pheidole SP01, and Tetramorium laevithorax were not strongly correlated with soil physicochemical parameters. Species of Pheidole SP02 and Camponotus SP05 were restricted to specific soil physicochemical properties, while species of Tetramorium zonacaciae and Bothroponera talpa discriminated between native tree species, coffee plantations, soil organic carbon, sandy soil texture, and aggregate stability. We concluded that these ant species can differently indicate the soil quality depending on the land use. We recommended further studies in order to generalize these findings.

Ants are abundant and ecologically dominant insects in most terrestrial communities. In subtropical ecosystems, there is a high turnover of species from the canopy to the top layers of the soil. Additionally, ant communities are often influenced by inter-specific competition. Collectively, these two processes (abiotic filtering and competition) make ants ideal for studies of community structure. We examined composition, co-occurrence, and species interactions in a sub-tropical forest ant community to examine how ground-foraging ant species partition microhabitats. We used four methods: pitfall traps, litter samples, surface baits, and subterranean baits. Surface baiting was employed at three different time periods to examine how foraging activity and species interactions at baits varied with time of day and temperature. Each method sampled a particular assemblage of the 97 total ant species. Pitfall traps shared ∼50% of species with surface baits and litter samples. Subterranean baits had the fewest total species but included some uncommonly sampled ants. The majority of interactions between species at baits were neutral, but a few agonistic interactions were also observed when bait occupancy was highest. Species co-occurrence patterns suggest that this ant community may not be heavily influenced by interspecific competition. Our results reinforce the advantages of applying complementary sampling techniques to examine ant community structure, and suggest that competition and dominance is best considered in the context of resource type, foraging strategy and time of sampling. Finally, we discuss the lack of two conspicuous Neotropical groups in our samples, leaf-cutting ant and army ants.

The longhorn beetles play important roles in the forest ecosystem processes and their diversity is affected by many environmental disturbances worldwide.This study aimed at understanding how the structural heterogeneity of the habitat can affect the longhorn beetle assemblage in three areas of an Atlantic Forest, which suffered differential impacts in the past and are now in different successional stages.The area in the most advanced successional stage had mainly lower density of trees, but with greater availability of dead wood, especially larger diameter classes. They are important forest components that contribute to the structural diversity of the habitat providing resources for a variety of dependent species. This area has also shown the greatest richness and abundance of longhorn beetles. Our results suggest that these beetles are closely associated with the structural heterogeneity of forests and can be valuable indicators for assessing biodiversity and quality of forest habitat. It also shows that old-growth forest remnants can be the key to the maintenance of the diversity of the longhorn beetles and, consequently, of the ecosystem services they provide.

Tropical forests account for 7% of the earth's surface harboring more than 50% of the biodiversity on Earth. Unfortunately, deforestation continues at high rates with negative consequences for biodiversity. With the decrease of natural habitats, biodiversity maintenance in areas degraded by human activity is a challenge. In order to maintain biodiversity, both in natural areas and in agro-ecosystems, knowledge of the structure and function of organism communities is important. Dung beetles (Scarabaeidae) play an important role in tropical ecosystems by recycling organic matter. Dung beetle diversity was appraised during 1 yr in an Atlantic forest remnant and five anthropic adjacent vegetation systems. In total, 1,047 individuals were sampled representing 17 species. Scybalocanthon nigriceps was the most abundant (523 individuals: 50%) almost exclusively in forest areas. Ataenius aff. platensis (48 individuals: 4.6%), and Canthon aff. luctuosus (109 individuals: 10.4%) were observed in all areas, while Canthon virens chalybaeus (111 individuals: 10.6%) was limited to anthropic areas. Dung beetle diversity was affected by microclimatic conditions concerning precipitation and air temperature. The greatest abundance and richness was found in the rainy season with a striking reduction in the dry period. The pasture sustained the lowest species diversity and abundance. However, there are clear signs that tree structure and microclimatic conditions similar to forests, as found in agroforestry, can help preserve biodiversity by creating a propitious habitat for native species. This is especially important in the forest regions of the Neotropics where dung beetles exhibit their greatest diversity. As dung beetles greatly depend on mammal feces and carrion, it is suggested that future studies incorporate the occurrence of mammals in investigations of the effects of landscape structure on scarab diversity.

Mutualistic associations between insects and microorganisms must imply gains for both partners, and the emphasis has mostly focused on coevolved host–symbiont systems. However, some insect hosts may have evolved traits that allow for various means of association with opportunistic microbial communities, especially when the microbes are omnipresent in their environment. It was previously shown that colonies of the subterranean termite Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae) build nests out of fecal material that host a community of Streptomyces Waksman and Henrici (Actinomycetales: Streptomycetaceae).These Actinobacteria produce an array of bioactive metabolites that provides a level of protection for termites against certain entomopathogenic fungi. How C. formosanus acquires and maintains this association remains unknown. This study shows that the majority of Streptomyces isolates found in field termite fecal nest materials are identical to Streptomyces isolates from soils surrounding the nests and are not vertically inherited. A survey of Streptomyces communities from C. formosanus fecal nest materials sampled at 20 locations around the world revealed that all nests are reliably associated with a diverse Streptomyces community.The C. formosanus fecal nest material therefore provides a nutritional framework that can recruit beneficial Streptomyces from the soil environment, in the absence of long-term coevolutionary processes. A diverse Streptomyces community is reliably present in soils, and subterranean termite colonies can acquire such facultative symbionts each social cycle into their fecal nest. This association probably emerged as an exaptation from the existing termite nest structure and benefits both the termite and the opportunistic colonizing bacteria.

We describe approaches to addressing the perennial challenge of collecting a sufficient diversity of nontarget insects for host-specificity testing of candidate biocontrol agents of invasive wood-borers such as the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae). Multifunnel and intercept traps, retrofitted to maintain live insects and baited with cerambycid-specific pheromone lures, were deployed in diverse forests in southeastern Massachusetts. We collected 1,288 adult beetles comprising 56 species, mostly from the subfamilies targeted by the lures (Cerambycinae and Lamiinae). The type of trap and tree species in which the trap was hung did not seem to affect the species caught. Methods used to induce egg laying and techniques to rear cerambycid larvae are described. Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is the most common Asian longhorned beetle parasitoid in China; therefore, we conducted tests to determine whether cerambycids native to North America would be at risk should this species be released. D. helophoroides attacked all six species tested: Monochamus scutellatus (Say) (Coleoptera: Cerambycidae: Lamiinae), Monochamus notatus (Drury) (Coleoptera: Cerambycidae: Lamiinae), Apriona rugicollis Chevrolat (Coleoptera: Cerambycidae: Lamiinae), Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae: Cerambycinae), Graphisurus fasciatus (DeGeer) (Coleoptera: Cerambycidae: Lamiinae), and Neoclytus acuminatus (F.) (Coleoptera: Cerambycidae: Cerambycinae). Parasitism of native cerambycids was not statistically different from parasitism of Asian longhorned beetle, except for N. acuminatus, which is a considerably smaller species than Asian longhorned beetle, and for M. notatus and M. scutellatus, which attack pine trees rather than hardwood trees like Asian longhorned beetle and the other native species tested. Our testing indicates that many native cerambycids would be vulnreable to D. helophoroides and we conclude that D. helophoroides should not be considered for release as a biocontrol agent in North America.

This study evaluated how the size of the egg mass and the parasitoids prior exposure to eggs influenced parasitism rates by Gryon pennsylvanicum Ashmead (Hymenoptera: Scelionidae) on egg masses of two squash bug species, Anasa tristis DeGeer and Anasa armigera Say (Hemiptera: Coreidae). G. pennsylvanicum is the primary egg parasitoid of A. tristis. There were no published reports available on egg parasitism of A. armigera. In choice tests, there was no difference in host acceptance by G. pennsylvanicum of egg masses of the two squash bug species. In no-choice tests, overall parasitism rates were significantly higher on A. armigera egg masses than on A. tristis egg masses. Naive parasitoids had significantly higher parasitism rates than experienced parasitoids on egg masses of both squash bug species. In a comparison of parasitism rates of field-collected and laboratory-tested A. tristis egg masses of different sizes, parasitism rates were similar in the field and in the laboratory, with the exception of egg masses with > 25 eggs. Only 17.9% of eggs were parasitized in the laboratory, compared with 36.4% in the field. Results of this study indicate that transient egg limitation prevents G. pennsylvanicum from ovipositing in every available host egg in large squash bug egg masses. The low parasitism rate of G. pennsylvanicum on large egg masses may limit its effectiveness as a biological control agent of squash bugs.

Stink bugs are important insect pests of soybean, Glycine max (L.), in Louisiana. Scouting, economic thresholds, and insecticide applications are the main strategies used in the integrated pest management of soybean insect pests. However, biological control of stink bug eggs by parasitoids has the potential to reduce populations of these pests. A survey of stink bug egg parasitoids was conducted at different sites in Louisiana from 2008 to 2010. Similarly, a study on the incidence of stink bug egg parasitoids within soybean vertical strata and plant structures was conducted in 2009 to 2011. Species of stink bug eggs collected during the studies included the redbanded stink bug, Piezodorus guildinii (Westwood), the brown stink bug species complex, Euschistus spp., the southern green stink bug, Nezara viridula L., the spined soldier bug, Podisus maculiventris (Say), and the green stink bug, Chinavia hilaris (Say). The percentage of stink bug eggs parasitized in the central location of Louisiana was higher compared with the northwest location during the 2008 to 2010 growing seasons. There were no differences in percentage of stink bug egg parasitism within soybean plant strata between 2009 and 2011. Telenomus podisi Ashmead (Hymenoptera: Platygastridae) was the most abundant parasitoid, and it showed preference for P. guildinii. Other platygastrid species that emerged included Trissolcus euschisti Ashmead (Hymenoptera: Platygastridae), Gryon obesum Masner (Hymenoptera: Platygastridae), and Telenomus longicornis Johnson (Hymenoptera: Platygastridae). This study is the first to report the parasitization of P. guildinii eggs on soybeans in the United States.

Honey bees (Apis mellifera L. (Hymenoptera: Apidae)) are effective pollinators of many crops but are thought to be inefficient in pollinating blueberries (Vaccinium corymbosum L.) due to their inability to buzz pollinate. Nonetheless, commercial growers rent honey bee hives for pollination, resulting in the dominance of honey bee workers visiting flowers during bloom.The objective of this study was to examine where on the honey bee pollen is carried and how it is transferred from flower to bee to the stigma of other flowers. Examination of 90 honey bee workers foraging on blueberry flowers documented that blueberry pollen tetrads were present on all body parts. Relative amounts were as follows: head 12%, body 6%, legs 19%, and tarsi 63%. Quantities on the body subregions ranged from an average of 400 tetrads on the basitarsi to 16 on the fore tarsal claws. Thus, a single contact between many of the pollen-carrying body parts and a stigma has the potential to transfer significant amounts of pollen. The study also revealed that bee behaviors unrelated to the intentional collection of nectar and pollen, such as the frequent touching of stigmas by the claws, tarsi, or legs, while foraging, grooming, and walking across flower clusters, could result in pollen transfer. These contacts occurred 65.9% of the time a honey bee landed on a flower cluster. These findings have broad implications for future assessments of the efficiencies of various bee species in pollinating diverse crops and plants.

Pathogen spread by arthropod vectors is the outcome of pathogen–vector–plant interactions, as well as how these interactions are impacted by abiotic and biotic factors. While plant water stress impacts each component of the Pierce's disease pathosystem (Xylella fastidiosa Wells et al., insect vectors, and grapevines), the outcome of interactions in relation to pathogen spread is unknown. The objectives of this study were 1) to determine the role of plant water stress on vector acquisition and inoculation of X. fastidiosa under choice and no-choice conditions for source or recipient vines, and 2) to provide insights into the effects of vineyard irrigation regimes on spread of X. fastidiosa by using a host–vector epidemic model. Under no-choice conditions, pathogen acquisition increased as water stress increased in source plants, while inoculation was not affected by water status of recipient vines. Thus, under no-choice conditions, plant water stress increased transmission of X. fastidiosa. However, when vectors had a choice of an uninfected well-watered versus an infected water-stressed grapevine, transmission efficiency declined as water stress levels increased. While our experimental results produced wide uncertainty estimates, the epidemiological modeling suggested a non-linear relationship between water stress and pathogen spread: moderate water stress enhances pathogen spread but severe or no stress produce equivalent spread. In summary, both host plant condition and vector host preference interacted to determine transmission efficiency of X. fastidiosa.

Fluctuating asymmetry (FA) is a widely used tool to detect developmental instability and plants under stressful conditions are expected to exhibit increased values of asymmetry, as well as higher levels of herbivory. This study evaluated whether dust from roads can cause major deviations in the axis of symmetry of leaves of the pioneer plant species Cecropia pachystachya Trécul (Urticaceae). It was also investigated whether plants exposed to dust have greater nitrogen content and higher levels of herbivory levels. Ten leaves of 20 individuals of C. pachystachya were collected on two roads with different levels of dust deposition and a control area. FA was calculated as the size-scaled difference between the right (RW) and left (LW) leaf widths and leaf area removed was determined by the ratio between leaf area removed and total leaf area. C. pachystachya plants in areas under strong influence of dust pollution exhibited the highest FA values (0.279 cm), whereas plants in the control area exhibited the lowest. A positive relationship between levels of leaf area removed by insects and a gradient of dust pollution was also observed. Differences in foliar nitrogen concentration among sampling areas indicated differences in leaf quality and influenced herbivory levels of Cecropia. This study indicated that FA can be used as an indicator of developmental instability of plants and those individuals under the impact of road dust and pollution might be more susceptible to insect attack.

The foraging patterns of insects reflect a combination of biotic and abiotic constraints. Pieris rapae (L.) (Lepidoptera: Pieridae) larvae exhibit plasticity in their foraging behavior, and their movements in response to flowers, young foliage, light, and gravity were studied. As predicted for palatable cryptic larvae, young instars of P. rapae exhibited predator avoidance behaviors. First- and second-instar larvae fed underneath the leaves where their eggs were oviposited, while late second- and third-instar larvae migrated away from their feeding damage. Using taxis experiments and choice tests, the direction of larval movement was significantly influenced by a hierarchy of three cues. Third-instar larvae exhibited negative gravitaxis, which could be supplanted by positive trophotaxis to young leaves and flowers. The larvae exhibited a significantly greater attraction to the inflorescence than to young foliage. For both the inflorescence and young foliage, visual cues were sufficient to direct larval movement. Understanding the cues that guide larval foraging may lead to more efficient trap crops for pest management.

Parasitoid wasps released as biological control agents may experience strong interspecific competition, which can lead to a reduction in pest control. The effects of competition can be mitigated if niche partitioning exists between species, such as parasitism preferences for different host stages. We examined host stage preferences for the parasitoids Encarsia noyesi Hayat (Hymenoptera: Aphelinidae), Idioporus affinis LaSalle and Polaszek (Hymenoptera: Pteromalidae), and Entedononecremnus krauteri Zolnerowich and Rose (Hymenoptera: Eulophidae). These parasitoids were introduced to the United States to control the giant whitefly Aleurodicus dugesii Cockerell (Hemiptera: Aleyrodidae), a pest of many economically important plants. Host stage preferences were examined using multiple metrics including: parasitism rates, relative preferences, handling times, and initial stage parasitism frequency. The data indicated differences in parasitoid preference hierarchies for the four A. dugesii nymphal stages. All A. dugesii nymphal stages were parasitized by I. affinis, which exhibited preference for the third instar. Unlike I. affinis, the first instar was not parasitized by E. noyesi, and its preference hierarchy differed with the fourth instar being the most preferred stage. The observed host-use breadth of E. krauteri was the narrowest observed of the three parasitoid species, only parasitizing the fourth and third instars, with a clear preference for the former. The observed differences in host-use breadth and stage preferences between parasitoid species in this system may promote their long-term coexistence in the field and facilitate biological control. Potential factors underlying the preferences exhibited by these parasitoids and their implications for biological control are discussed.

Brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a serious agricultural pest and can be a significant nuisance when it invades human dwellings during its fall dispersal to overwintering sites. Methods informed by behavioral data to exclude or reduce its entry into buildings are needed. The temporal and spatial distribution of adults on an invaded building was assessed over multiple years, revealing its seasonal dispersal pattern and that its numbers varied by wall aspect. Moreover, its density was higher in recessed doorways than on associated walls, raising questions about its behavioral response to dark, contrasting surfaces. This response was evaluated using black, framed panels of deltamethrin-incorporated netting, non-treated netting, and an open frame with no netting, deployed in pairs on the wall of a private residence. More dispersing adults landed on panels of non-treated netting than on open panels, but there was no difference between panels with treated and non-treated netting. Adults remained on treated panels for less time than on non-treated panels, and most walked rather than flew from both. Adult male and female H. halys collected during the dispersal period were exposed to panels of treated and non-treated netting in a laboratory, using durations derived from field recordings. Exposures to treated panels intoxicated but did not kill them over a 7-d assessment period. The deployment of insecticidetreated netting, guided by the behavior of adult H. halys alighting on buildings, is discussed in relation to potential options to mitigate homeowner issues from this serious annual problem.

Fungus-growing termites are major contributors to litter decomposition and an agriculture pest in tropical and subtropical Africa and Asia. The foraging behavior of fungus-growing termites was hypothesized to be seasonal and may associate with climatic factors and the occurrence of natural enemies. In this study, we tested the effects of climatic factors and the presence of ants on the foraging activity of the fungus-growing termite Odontotermes formosanus (Shiraki) (Blattodea: Termitidae). Termite-foraging activities were quantified monthly based on the number of wood stakes occupied, amount of wood consumed, and foraging population size. The rate of wood-stake decomposition was measured by monitoring 484 wood stakes in a tropical forest over the course of nearly 6 yr. The results revealed that temperature and rainfall are the major climatic factors influencing the foraging seasonality of O. formosanus. Termites occupied fewer wood stakes during hot–wet seasons when fewer ants were present. The results of a path analysis supported that termite-foraging seasonality correlated mainly with climatic factors rather than the presence of ants. A new foraging hypothesis, the eat-and-run strategy, is proposed to explain the inconsistent seasonal foraging behaviors observed in fungus-growing termites.

Winter canola Brassica napus L. (Brassicales: Brassicaceae) was introduced to U.S. Southern Great Plains (Kansas, Oklahoma, Texas) growers to manage some difficult-to-control grassy weeds in winter wheat Triticum aestivum L. (Poales: Poaceae). Two braconid parasitoids, Diaeretiella rapae (M’Intosh) and Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae) are active in this cropping landscape. Both wasps move between crops but D. rapae has a limited ability to develop in the main wheat aphid hosts, so L. testaceipes could influence D. rapae's ability to maintain itself when canola is absent in the landscape. We compared behavioral responses of naturally emerged D. rapae and wasps that were excised before emergence to odor volatiles of host plant, aphid host and aphid-infested plants using two plant/aphid combinations (wheat/Rhopalosiphum padi (L.) and canola/Brevocoryne brassicae L. (Hemiptera: Aphididae). We also compared parasitism rates of D. rapae that were naturally emerged and excised from R. padi or B. brassicae on subsequent parasitism rates of R. padi or B. brassicae hosts. Naturally emerged wasps responded more strongly to host plant and host plant + aphid odors compared to excised wasps regardless of the host origin. Neither wasp group responded to odors from aphids alone. Both wasp groups were most attracted to odors from aphid-infested host plants, regardless of the combination. D. rapae parasitism rates on canola-reared aphids were higher than on wheat-reared aphids. D. rapae parasitism rates were lower when switched from its original host to the alternate host. Results suggest that D. rapae faces challenges to maintain significant populations in the wheat/canola landscape of the Southern Great Plains, especially in years when canola is not locally present.

The annual bluegrass weevil, Listronotus maculicollis Kirby, is a severe pest of short-mown turfgrasses in eastern North America. Previous research has demonstrated that adults can be removed from golf course putting greens during mowing. However, the impact of mechanical control on adult removal diminishes with increases in mowing height. Therefore, to optimize adult removal we sought to describe adult presence on top of the turfgrass canopy to identify periods when mowing would be most effective. Growth chamber studies using time-lapse photography revealed that greatest activity occurred between 15 and 20°C, with few weevils active on the surface when temperatures were less than 10°C. A mark-release technique combining fluorescent marks with still photography was used to assess adult movement in the field.This novel mark-recapture system confirmed laboratory findings that adult activity on top of the turfgrass canopy was greatest during the day and strongly correlated with temperature early in the season (April, May). However, adult presence on the surface in early summer was greatest briefly after sunrise, then declined during the mid-morning when temperatures exceeded 21°C. The effect of temperature on surface activity was best described by a second-order polynomial function, which predicts maximum adult surface activity between 14 and 17°C. Our findings suggest that adult surface activity is strongly associated with temperature and not photophase, and therefore, monitoring populations and scheduling mowing with the intent to remove adults need to be adjusted seasonally with changes in temperature.

In the Central American region, the aggressive, sibling bark beetles Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) and Dendroctonus mesoamericanus Armendáriz-Toledano & Sullivan (Coleoptera: Curculionidae: Scolytinae) commonly colonize pines concurrently, and in nature they avoid heterospecific pairing, although it can be produced in the lab. We performed walking arrestment bioassays in the lab to examine the capacity of both sexes of both species to discriminate odors from frass expelled from gallery entrances of either solitary females or conspecific pairs of either species. Males of both species strongly preferred odors of frass from solitary, conspecific females over those of heterospecific females or pairs of either species. Female D. frontalis did not discriminate among these frass categories, whereas female D. mesoamericanus preferred frass of conspecific females. In gas chromatography–electroantennographic detection and gas chromatography–mass spectrometry analyses, we determined that males of both species could sense a nearly identical spectrum of approximately 16 host- and beetle-produced compounds present in frass of females of one or both species. Only two of these compounds, endo-brevicomin and ipsdienol, which were present in frass of female D. mesoamericanus and pairs of either species but absent in frass of solitary D. frontalis females, qualitatively distinguished these categories. Several known attractants and synergists for either species declined in concentration postpairing. Our results complement earlier research and indicate how semiochemical composition and concentration in frass might mediate male discrimination of attack sites of conspecific, unpaired females. Furthermore, our data indicate that semiochemical responses for walking females differ from those of males and between species.

A series of bioassays involving a four-choice olfactometer were conducted to assess the behavioral responsiveness of adult hunting billbugs (Sphenophorus venatus vestitus Chittenden) towards odors emanating from samples of three different turfgrasses: tall fescue (Festuca arundinacea Schreb. (Poales: Poaceae)), Kentucky bluegrass (Poa pratensis L. (Poales: Poaceae)), and zoysiagrass (Zoysia japonica Steud. (Poales: Poaceae)). When exposed to the three turf species simultaneously, the majority of billbugs preferred the zoysiagrass treatment over the tall fescue and Kentucky bluegrass treatments. When billbugs of both sexes were added to the three turf treatments, their presence with the turf did not enhance the released billbugs preference towards any of the treatments. Without the presence of turf, the released female billbugs were strongly attracted towards the male-only billbug treatment; however, a similar phenomenon was not observed for males. When a single turf type and/or mixed-sex adult billbugs were presented, treatments that contained the turf, especially zoysiagrass and tall fescue, strongly attracted the released billbugs compared with treatments that contained billbugs only. In the final bioassay experiment when billbugs were exposed to treatments of zoysiagrass and zoysiagrass + billbugs (with either sex), the released billbugs showed a significant preference towards the zoysiagrass + male billbugs treatment. Collectively, this series of experiments demonstrated the hunting billbugs preference to all three turf species tested, and their attraction to male conspecifics. This overall study was the first to investigate some basic aspects of the chemical ecology of the hunting billbug; specifically, the role turfgrass and adult billbug volatiles might have in billbug orientation and host selection.

We report here the pheromone of Megacyllene antennata (White) (Coleoptera: Cerambycidae), a species native to southwestern North America whose larvae feed in woody tissues of mesquite (Prosopis species; Fabaceae). Adult males sex-specifically produced a blend of eight common natural products, including the monoterpene alcohol (S)-α-terpineol; the monoterpenes (S)-limonene and terpinolene; the aromatic alcohols (R)-1-phenylethanol and 2-phenylethanol; and (E)-2-hexenol, (E)-2-hexenal, and 1-hexanol. Individual males produced the components in varying amounts, but (S)-α-terpineol and (E)-2-hexenal were always present and together constituted the majority of the blend. A synthetic reconstruction of the complete blend attracted both males and females of M. antennata during field bioassays, as did all subsets of the blend that included (S)-α-terpineol and (E)-2-hexenol. Adults were most strongly attracted to blends of the latter two compounds when in ratios approaching parity. Neither of the compounds were present in the bouquet of volatiles emitted by host plants of the larvae.

Previously, we showed that the symbiotic yeast Lachancea thermotolerans (Filippov) (Saccharomycetales: Saccharomycetaceae) is attractive to its Vespula (Hymenoptera: Vespidae) yellowjacket hosts when grown on media supplemented with grape juice. We hypothesized that “Concerto”, a commercial strain of this yeast, could be combined with fruit powder to form a shelf-stable bait for trapping yellowjackets. Using molecular techniques, we first confirmed that Concerto yeast is indeed the species L. thermotolerans. We then tested whether: 1) Concerto yeast produces volatiles similar to those produced by L. thermotolerans isolated from yellowjackets, 2) Concerto yeast enhances attraction of yellowjackets to fruit powder, 3) a Concerto yeast/fruit powder bait interacts synergistically with a yellowjacket semiochemical lure, and 4) a synthetic analog blend of Concerto-produced volatiles attracts yellowjackets. Using gas chromatography–mass spectrometry, we demonstrated that the chemical composition of Concerto-produced volatiles closely resembles that produced by a yellowjacket-isolated strain of L. thermotolerans. In field experiments, addition of Concerto to fruit powder doubled its attractiveness to yellowjackets. Addition of the Concerto/fruit powder bait to a heptyl butyrate–based wasp lure revealed a weak additive effect. A threecomponent synthetic analog blend of volatiles identified from the Concerto/fruit powder bait attracted Vespula pensylvanica (Saussure), but no other yellowjacket species. Our results suggest that commercial L. thermotolerans in combination with fruit powder could be used as a yellowjacket bait, and that addition of yeast-produced volatiles to a commercial wasp lure may improve its attractiveness to V. pensylvanica. Further research should determine why the synthetic volatile blend failed to attract Vespula species other than V. pensylvanica.

The onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a polyphagous pest that causes serious damage to agricultural crops, vegetables, and ornamental plants worldwide. Farmers rely on the extensive usage of synthetic chemical insecticides to control T. tabaci. There is a dire need to develop alternative control strategies to overcome the problems posed by chemical insecticides. Efficient traps would allow sensitive monitoring and possibly mass trapping. A field experiment was conducted to evaluate the potential of three plant compounds with known release rates (ranging from 6–30 mg/d); eugenol (Eug), 1, 8-cineole (eucalyptol), and linalool in all possible combinations with a thrips attractant, ethyl iso-nicotinate (EI). A combination of EI with Eug increased the effect of EI by attracting 100% more thrips (effect size, 1.95) as compared to the control of EI alone. Catches in remaining treatments were lower and or not significantly different from EI alone. The results from our study could be used to develop improved volatile blends to be used for monitoring traps. Our data suggests that these traps could be effective even at very low populations.

Understanding how biodiversity is distributed across space and time is one of the main challenges of biological conservation. Moreover, the choice of an adequate sampling methodology is crucial since this must provide an efficient overview of species diversity. We assessed the effectiveness and complementarity of three sampling methods (hand collection [HC], pitfall trapping [PT], and light trapping [LT]) for collecting ground beetles, which are known as a robust ecological indicator sensitive to habitat modifications. Our results varied in the number of species and abundance thereof caught by each sampling method. Both HC and LT were the most efficient and showed the highest species complementarity. HC recorded the highest number of ground beetle individuals, whereas the largest number of species were recorded with LT, but most represented by few individuals. Furthermore, the results revealed that PT do not work efficiently to provide reliable inventories in the remnant riparian cloud forests, which are characterized to be a highly heterogeneous environment. Our results might provide guidelines to choose the most efficient standardized sampling protocol for future inventory and monitoring of ground beetle (Coleoptera: Carabidae) diversity as a tool for the conservation planning in this threatened ecosystem.

Neonate pigs have been used as decomposition models in experimental forensic entomology studies. Their small size, however, poses challenges to traditional sampling methods of necrophilous insects, like the sweep net, the most commonly used sampling method in forensic entomology research and practice. Previous research experimentally demonstrated the potential for sticky traps as an effective sampling method for collecting necrophilous insects from neonate pigs. While sticky traps effectively sampled fly diversity from the pigs, they shared with the sweep net low sample diversity and abundance, particularly of necrophilous beetles. Motivated by chemosensory host-finding of necrophilous insects and the architecture of carrion-mimicking thermogenic flowers, we developed a ‘ventedchamber’ method and optimized its design experimentally. In this approach, a neonate pig was transiently enclosed in a chamber. The decomposition process thermally convected the natural decomposition odors in the headspace above the pig toward a pair of sticky traps. The vented-chamber method collected significantly more necrophilous flies, representing a greater diversity, than the sweep net. Nevertheless, this approach caught few beetles, and hand collections must be used as well to most effectively sample beetle diversity.

Megaselia scalaris (Loew) (Diptera: Phoridae) provides great evidential value in estimating the postmortem interval (PMI) compared with other dipterans due to its common occurrence on human corpses both indoors and in concealed environments. Studies have focused on the effect of temperature, larval diet, and photoperiod on the development of the species; however, knowledge of M. scalaris development at different moisture levels is insufficient. This study aimed to investigate the effects of substrate moisture on the larval development time, pupal recovery, pupal weight, adult emergence, and adult head width of M. scalaris. The larvae were reared in five replicates on substrates with six moisture levels ranging from 50 to 90%. Larvae and puparia were sampled daily, and the collection time, number, and weight were recorded, measured, and then compared using multivariate analysis of variance with a post hoc least significant difference test. Larvae developed most quickly (3.75 ± 0.04 d) at 50% substrate moisture; the larvae were able to survive in extremely wet substrates (90% moisture), but the development time was significantly longer (6.48 ± 0.19 d). Moisture greatly influenced the pupation rate and adult emergence but showed a weak effect on the pupae weight and adult head width. Due to the significance of moisture on the development of M. scalaris, PMI estimation using M. scalaris with cadavers of different moisture content must be carefully conducted to avoid inaccuracy.

The invasive giant whitefly Aleurodicus dugesii Cockerell (Hemiptera: Aleyrodidae) is a pest of over 300 plants species in the United States, many of which are economically important ornamentals and crops. Development and survival of A. dugesii was assessed at seven constant temperatures ranging from 10 to 35°C to provide a basis for phenological forecasting and assist in enhancing current biological control strategies. Complete development occurred from 15 to 28°C, with partial development occurring at 30°C. Development time differed between sexes, with males developing 2 (at 25°C) to 6 (at 15 and 28°C) d faster than females. Adult survival was highest at 25°C (65.4%), with survival rate declining rapidly at other temperatures. The relationship between temperature and development was evaluated using five nonlinear models (Lactin-2, Brière-1 and 2, Beta, and LRF). Additionally, the simple linear regression was used to calculate developmental degree-days (DDs). While all five nonlinear models evaluated fit the data well, the Brière-1 model provided the best fit of the data and estimated the optimal (25.3°C), lower (9.9°C), and upper (30.0°C) developmental thresholds for male and female complete development. Using linear regression, DDs for complete development were calculated as 408 and 435 for males and females, respectively. The results of this study emphasize A. dugesii survival and development under varied temperature conditions.

Characterization of intraspecific variation is required to assess the potential nontarget effects of augmentative releases of Hippodamia convergens (Guerin) (Coleoptera: Coccinellidae) from the Western United States on local populations of this species in the Eastern United States. Adults of this predatory lady beetle species overwinter in adult reproductive diapause, thus examining responses to photoperiods can characterize geographic variation influencing their seasonal biology. This laboratory study quantified the induction and duration of adult reproductive diapause in five North American populations of H. convergens in response to four constant photoperiods (16:8, 14:10, 12:12, and 10:14 [L:D] h) at 22°C. Three populations were collected over a range of latitudes (31° N to 42° N) in the central portion of the United States (Texas, Kansas, and Iowa); two populations were purchased from commercial sources in the Western United States. All populations exhibited a long-day response to photoperiods: ≤17% of females reared at 16:8 (L:D) h entered diapause, whereas shorter photoperiods (12:12 and 10:14 [L:D] h) induced diapause in 82 to 100% of females. The response to 14:10 (L:D) h showed significant variation among the populations, ranging from 0 to 89% of females in reproductive diapause. Both the phenotypic variation in response to diapause inducing photoperiods and the genetic variation in North American populations of H. convergens document the geographic variability in this widely distributed predatory species.

Many organisms exhibit changes in phenotypic traits as a response to seasonal environmental variation. We investigated the role of habitat in generating seasonal polyphenism in different populations of the light bush brown butterfly Bicyclus dorothea (Cramer, 1779) (Lepidoptera: Nymphalidae) in Cameroon. Butterflies were caught during the wet and dry seasons across four localities representing two distinct habitats, namely forest and ecotone (forest–savanna transition zone) over a 2-yr period (2015–2016). We found distinct variation in the wing pattern characteristics of butterflies in response to seasonality and habitat. Specifically we observed that: 1) all wing characters are not seasonally plastic in B. dorothea; 2) populations from ecotone tend to be more variable, with individuals exhibiting wings with large spots during the wet season and very reduced spots in the dry season while in forest populations, individuals exhibit wings with large spots during the wet season, but in the dry season, spots are not as greatly reduced as their ecotone counterparts; 3) this polyphenism in B. dorothea alternated consistently during the wet and dry seasons over the 2 yr of sampling. Bicyclus species have become a textbook example of seasonal polyphenism while this study extends this model system to the unique forest–ecotone gradient of Central Africa and demonstrates the complexity of seasonal forms in different habitats.

This study aimed to determine the suitability of several organic waste substrates to be processed by the larvae of the black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae) (BSFL) in a value-added bioconversion system. Three types of organic waste (brewer's waste, solid phase of pig manure, and semidigested grass) were tested and compared with a standard larval diet, broll (wheat middling). Larval survival and growth, chemical composition of the resulting prepupae, conversion ratios of nutrients and waste dry matter, and waste reduction rate were measured. Larval survival was high in all tested substrates. Compared with the larvae fed pig manure or semidigested grass, those fed standard diet or brewer's waste showed shorter development time, higher weight gain, and higher prepupal crude protein and crude fat content. BSFL also reduce more dry matter in the standard diet or in brewer's waste than in the other two substrates. On the other hand, larvae fed semidigested grass took 70 d to complete development and suffered fat loss. Thus, we suggest that brewer's waste is the most suitable substrate among the selected wastes for being processed by BSFL, whereas semidigested grass is an unsuitable substrate. We found that lignin had a significantly negative effect on larval growth, and emphasized the importance of applying lignindigesting microorganisms to lignin-rich substrates being converted by BSFL. Moreover, a protein:fat:digestible carbohydrate ratio of 2:1:2 was hypothesized to benefit larval development.

Animals rely on carotenoids as fundamental precursors for hormones and antioxidants, and animals must acquire carotenoids from their diet. Previous research has shown that insects often absorb carotenoids in amounts proportional to those in their diet, and that carotenoids play key roles in multitrophic interactions.The consumption of diets that provide high levels of antioxidant compounds is associated with high levels of immune responses; however, it is unknown whether individual carotenoids directly influence immune response. Here, the objective of this study was to examine the effect of the carotenoid β-carotene on melanization, a measure of immune response, and growth rate of Trichoplusia ni Hübner (Lepidoptera: Noctuidae).To fulfill the objective, a low, medium, and high concentration of β-carotene, representing the range found in typical host plants, were mixed in an artificial diet, and immune response and growth rate were assessed in fifth instar larvae. Immune response was induced by injection of chromatography beads in to the abdomen of the larvae, and percent melanization was measured after injection. Melanization was greatest when larvae were reared on high β-carotene diets. Mass was measured at 5 and 10 d to assess growth rate. Larvae reared on high β-carotene diets initially gained little mass, but after 10 d larvae reared on no and high β-carotene diets were larger than those reared on other diets.This research has shown that β-carotene has the potential to influence the immune response and growth rate of T. ni.

As global temperatures rise, thermal limits play an increasingly important role in determining the persistence and spread of invasive species. Gypsy moth (Lymantria dispar L. Lepidoptera: Erebidae) in North America provides an ideal system for studying the effect of high temperatures on invasive species performance. Here, we used fluctuating temperature regimes and exposed gypsy moth at specific points in development (first–fourth instar, pupa) to cycles of favorable (22–28°C) or high-temperature treatments (30–36°C, 32–38°C, 34–40°C) for either 2 or 7 d. We measured survival, growth, and prolonged effects of exposure on development time and pupal mass. Survival generally decreased as the experimental temperature treatment and duration of exposure increased for all instars and pupae, with a narrow threshold for lethal effects. In response to increasing temperature and magnified by longer exposure times, growth abruptly declined for third instars and development time increased for pupae. For those surviving the 2-d exposure treatment, development time to pupation increased for all instars, but we did not find consistent effects on final pupal mass. These negative effects of high temperature provide important data on the susceptibility of gypsy moth to heat at different points in development. This work improves our understanding of thermal limits to growth and development in gypsy moth and can aid in determining invasion potential under current and future climates.

Marsh flies are a diverse family that provide valuable ecosystem services, including the biological control of mollusks that are agricultural pests and vectors of animal and human parasitic diseases. In addition, some species may serve as important ecological bioindicators. Despite the extensive research on this family, most have centered on larval diet and behavior, as this is the life stage primarily used for biological control; virtually nothing is known about the natural dietary components of adult marsh flies. Our study aimed to close this knowledge gap by examining the dietary range and preference of adult marsh fly species. Individual flies were provided with five food choices in cafeteria-style food choice trials, consisting of crushed snail, freshly killed slug, glucose solution, honey-yeast mixture (the standard laboratory rearing diet), or water. Sciomyzidae at family level displayed significant differences in food selection (P = 0.0212), with carbohydrates (honey-yeast and glucose solution) significantly preferred over protein options (mollusk tissue) or the water control (P < 0.001). This suggests that marsh flies may naturally maintain a carbohydrate-rich diet. Because many plants typical at field sites produce little or no nectar, a second experiment aimed to determine the source of these carbohydrates in nature. When presented with honeydew harvested from aphids (Hemiptera: Auchenorrhycha), Tetanocera elata Fabricius (Diptera: Sciomyzidae) individuals were observed to feed on dry honeydew and honeydew solution significantly more frequently than the water control (P < 0.001 and P = 0.01969, respectively), suggesting that honeydew may play an important role in adult marsh fly diet.