Transgenic corn has been modified to express a gene derived from the bacterium Bacillus thuringiensis (Bt) to combat lepidopteran pests. Bt proteins and the altered chemical composition of Bt crops may affect the role the soil fauna plays in the decomposition of Bt plants. A 2-y field study and a laboratory feeding experiment using corn leaves were conducted in northeastern China to investigate the effect of Bt corn—consisting of Bt corn (Bt 38) and a near-isoline of non-Bt corn (Z 58)—on the abundance, species richness, morphological traits, community structure, and fitness of soil Collembola. A total of 4,419 collembolans, comprised of 22 species, were recovered in this study. We found that Bt corn cultivation did not significantly affect abundance, species richness, or community structure of Collembola. Some rare isotomids of the genera Desoria Nicolet, 1841 (Collembola: Isotomidae) and Folsomia Willem, 1902 (Collembola: Isotomidae) were only recorded in non-Bt corn varieties and not in Bt corn varieties. Morphological traits, including the number of ocelli, body size, body pigmentation level, furca development, antennal length, and antenna:head ratio of Collembola were not changed by transgenic corn cultivation in the 2-y field study. Our results clearly found that the Bt corn did not affect community characteristics or traits of Collembola during this 2-y field study.

Self-repair in the animal world typically involves regeneration of body parts. We present an example featuring the proboscis of butterflies and moths, which after separation of the galeae, undergoes nonregenerative repair. We demonstrated the ability of representative species to completely reunite (repair) the proboscis after total separation of the two galeae, and we showed that the repaired proboscis can take up fluid. Movements of the proboscis during repair were similar to the initial proboscis assembly after emergence from the pupa. We tested the influence of labial palps, wing movements, coiling, and fluid immersion on self-repair. These factors showed no statistically significant influence on the ability to repair the proboscis, with the exception of wing movements in one species. We suggest that the major selection forces driving assembly and repair have been the need to insert the proboscis into restricted openings of floral tubes to obtain nectar and the need for a united, compactly coiled proboscis to reduce air resistance during flight.

Neotropical butterflies in the nymphalid genera Pierella Herrich-Schäffer, 1865 (Lepidoptera, Nymphalidae) and Cithaerias Hübner, 1819 (Lepidoptera, Nymphalidae) are known to glide near ground level, and have a high forewing aspect ratio.The hind wings of Pierella are proportionately larger than those of Cithaerias, suggesting a potential role in gliding flight. We show that Pierella helvina (Hewitson, 1860) (Lepidoptera, Nymphalidae) is capable of gliding for longer periods of time than Cithaerias pireta (Stoll, 1780) (Lepidoptera, Nymphalidae) both in the field and a laboratory setting. Experimental reduction of hind wing area in P. helvina led to a decrease in male gliding performance, and an increase in female wing-beat frequency. We also found that escape velocity decreased in both sexes after hind wing area reduction, but the effect was strongest in females. Although the increased drag associated with large hind wings could be detrimental to gliding flight, the large hind wing area of P. helvina effectively enhances gliding performance in ground effect.This study is the first to investigate the role of hind wings on butterfly gliding performance.

The attraction of entomopathogenic nematodes (EPNs) to herbivore-injured plant roots has been documented recently to be a common tritrophic interaction. Belowground tritrophic interactions are especially subject to modulation by many abiotic factors including drought. In this study, complementary greenhouse experiments were conducted to understand how drought stress might affect a potato plant's impact on EPN behavior. In separate trials, the responses of the EPN Steinernema diaprepesi (Nguyen and Duncan) (Rhabditida: Steinernematidae) to root herbivory by larvae of the weevil Diaprepes abbreviatus (Linnaeus) (Coleoptera: Curculionidae), in well-watered and drought stressed potato plants, were measured using soil-matrix olfactometers with two arms. The drought treatments were initiated in 30-d old plants. Drought-stressed potato plants received water when potentiometers read approximately 20 kPa, while for well-watered plants, the number was 8 kPa. Four weeks after initiating the treatments, 400 ml water was added to all pots, immediately before starting the experiments. The experiments revealed that S. diaprepesi infective juveniles (IJs) did not migrate preferentially toward drought-stressed or well-watered plants when neither were subjected to herbivory [t₍₂₁₎ = 1.13, P = 0.269]. However, plants with roots damaged by herbivory attracted more S. diaprepesi IJs if they were well watered than if they were drought stressed [t₍₂₄₎ = 3.19, P = 0.004]. If both plants in the olfactometers were drought stressed, EPNs moved preferentially toward those with root herbivory than those with undamaged roots [t₍₂₃₎ = 3.19, P = 0.004]. No difference was detected in gas chromatography profiles between droughted and well-watered plant roots subjected to herbivory [F_{(24, 336)} = 0.68, P = 0.87]. GC analysis showed that three compounds, including 3-nonanone [t₍₆₎ = 4.83, P = 0.003], artemisyl ketone [t₍₇₎ = 6.21, P = 0.000], and benzoic acid, 4-ethoxy-, ethyl ester [t₍₇₎ = –4.22, P = 0.004] were significantly higher in drought stressed than control plant roots. These results indicate that potatoes, like other plants, can recruit EPNs in response to root herbivory, and that drought stress dampens this tritrophic interaction where choice is involved. Additional research that resolves the mechanisms of these interactions may provide insights to exploit EPNs for crop protection.

Fruits of Miconia calvescens DC. (Melastomataceae) were dissected to study insect frugivory in this plant in its native habitat in Costa Rica. Larvae of an unknown Mompha species (Lepidoptera: Momphidae), Anthonomus monostigma Champion (Coleoptera: Curculionidae), and unidentified Diptera and Hymenoptera were found in M. calvescens fruits. The Mompha species, described here as new as Mompha luteofascia Koster & Badenes-Pérez, was the most abundant insect frugivore in M. calvescens, infesting up to 38.1% of the fruits sampled. Feeding damage by M. luteofascia was positively correlated with fruit maturity, and resulted in significantly reduced numbers of seeds and rates of seed germination. Miconia calvescens fruits with medium damage (50–75% of the pulp missing) and high damage (75–100% of the pulp missing) had an average of 96 and 99 seeds, respectively, whereas undamaged fruits contained an average of 127 seeds per fruit. In fruits with medium and high fruit damage, only 1.9 and 0.1% of the seeds germinated, respectively, whereas 34.8% of the seeds germinated in undamaged fruits. Mompha luteofascia developed through three instars, as determined from measurement of head capsules. Larvae usually fed as one individual per each fruit attacked, exiting fruit to pupate in foliage or litter. Parasitism of M. luteofascia larvae was substantial, averaging 64 and 38% at the two study sites. Although host specificity of M. luteofascia has not been evaluated, the significant reductions in seed numbers and seed germination caused by its larvae indicate that this species deserves further assessment as a potential biological control agent of M. calvescens.

The epicuticular compounds (ECs) of insects serve both to waterproof the cuticle and, in many taxa, as pheromones that are important for various social interactions, including mate choice within populations. However, ECs have not been individually identified in many species and most studies of their role in mate choice have been performed in a laboratory setting. Here we newly identify and quantify the ECs of the antler fly, Protopiophila litigata Bonduriansky, and use a cross-sectional selection analysis to quantify their association with male mating success in the wild across two years (2013 and 2017).The ECs of antler flies include straight-chain and methylated alkanes, alkenes, and a family of branched wax esters. We find all ECs to be shared between males and females but also demonstrate sexual dimorphism in the abundance of several. Male EC relative abundances were significantly associated with mating success in both years, although the multivariate direction of selection differed significantly between the years. Surprisingly, only two of the 18 compounds (or groups of compounds) we identified were similarly associated with mating success across the sampling years. In 2017, we further partitioned sexual selection into intra- and intersexual components, revealing selection on ECs to be significant via female choice but not male–male competition. Our study is one of few to investigate the potential role of ECs in mating success in the wild and adds to a growing body of evidence demonstrating significant temporal variability in selection in natural populations.

Blaptostethus pallescens Poppius is an important predator of vegetable pests in tropical regions. The correct identification of the stages of the life cycle of predatory species is crucial, since different stages may present different rates of pest consumption. Artificial neural networks (ANNs) are computational tools with a structure based on the human brain. With applications in several fields, ANNs have been applied in pest management for identification of pest species, spatial distribution modeling, and insect forecasting. The objective of this study was to apply ANNs as a method for the instar determination of B. pallescens using three morphometric measures (head width, body width, and body length). Cluster analysis was performed to categorize the insects in instars according to the morphometric variables. Subsequently, the ANNs were trained for instar determination using the morphometric measures as input variables. The ANNs tested (with 2, 4, 6, 8, 10, and 12 hidden neurons) provided proper data fitting (R² > 98%). However, due to the parsimony principle, the network with hidden layer size 6 was selected. This study shows the successful application of ANNs in the instar determination of B. pallescens, which would not be possible using classical methods.

Diapause is a common phenomenon during which organisms suspend development to overcome difficult environmental conditions. The silkworm is a classical model for the study of egg diapause. Our previous study showed that gene expression is similar in silkworm eggs treated with hyperoxia or HCl. In the present study, to further explore the mechanism of diapause prevention, nondiapause eggs and hyperoxia-/HCl-activated diapause eggs were treated with hypoxia. Embryo morphology, hatching time, and reactive oxygen species (ROS) levels were analyzed across different developmental stages. The results showed that hypoxia may inhibit the embryonic development of silkworm eggs.The morphology of nondiapause eggs under hypoxia differed from that of nondiapause eggs under normoxia during embryonic development, which, in turn, was similar to that of diapause eggs. Meanwhile, the hatching time of nondiapause eggs under hypoxia was delayed significantly. Moreover, the ROS levels of nondiapause eggs changed under hypoxia, showing a pattern similar to that of diapause eggs. Interestingly, when activated diapause eggs were treated with hypoxia, some eggs hatched in the following spring. These results suggest that early embryogenesis is largely dependent on oxygen levels and that hypoxia may induce a diapause-like state in activated diapause eggs. Additionally, ROS levels may play a key role in diapause.Thus, this study provides valuable information on the mechanisms of diapause and diapause prevention in silkworms.