Journal of Insect Science最新文献

Generalist arthropod predators have historically contributed to the suppression of arthropod pests in many agroecosystems. The successful implementation of integrated pest management (IPM) programs hinges on the incorporation of insecticides that are compatible with the biological attributes of natural enemies of pests. A potentially promising pathway is improving biological control by natural enemies through the timely application of selective insecticides. In our study, adult predators were exposed to commercially available insecticides (cyantraniliprole and pyriproxyfen) using a combined laboratory and field approach to assess their effects on survivorship and predation. We isolated 2 predators, Hippodamia convergens Guérin-Méneville and Geocoris punctipes (Say), in the laboratory to estimate the survivorship and consumption of whitefly nymphs, Bemisia tabaci (Gennadius). In the field, we deployed whitefly nymph-infested potted cotton plants in replicated cotton plots with both insecticide treatments. We enumerated whitefly nymph populations on enclosed (predator-exclusion) and open (predator-accessible) potted plants. While pyriproxyfen had a negligible effect on the predators, cyantraniliprole exposure directly affected H. convergence by reducing survivorship duration and indirectly influenced both predators by reducing prey consumption and altering the consumption of alternative prey. In field conditions, regardless of pesticide exposure, whitefly-infested potted plants that excluded predators had more whiteflies than predator-accessible potted plants. Overall, pyriproxyfen demonstrated minimal impact on the predators in the laboratory or field, while cyantraniliprole adversely influenced mortality and indirect foraging under controlled laboratory conditions but did not have a significant impact in the field.

Glenea cantor (Fabricius) is an important forest pest that mainly attacks kapok trees, breaking down cellulose and lignin through 3 enzyme activities: endoglucanase, filter paper enzyme, and cellobiase. In this study, we unveiled the cloning and expression of 10 endoglucanase genes, GcEGase5A1, GcEGase5A2, GcEGaseZ2, GcEGaseZ3, GcEGaseZ4, GcEGaseZ5, GcEGaseZ7, GcEGaseZ8, GcEGaseZ9, and Cellulase, all of which exhibit enzymatic activities in G. cantor. These findings indicated that Cellulase shares sequence homology with beetle GHF45, whereas the other 9 endoglucanase genes are homologous to beetle GHF5. GcEGaseZ4 presented the highest expression in the foregut. In contrast, GcEGase5A2 and Cellulase presented peak expression in the midgut. Furthermore, GcEGaseZ7 was identified as the most highly expressed endoglucanase in the hindgut. Functional assays confirmed the ability of GcEGaseZ7 and Cellulase to degrade cellulose, and their cellulase activities were 75.57 ± 1.21 U/mg and 344.79 ± 6.91 U/mg, respectively. These results enhance our understanding of the complex cellulase system in insects and provide insights into the efficient digestion of cellulosic materials by wood-consuming insects. This research also has potential applications in bioenergy production and the development of biomaterials from lignocellulosic biomass.

In parasitoid wasps, body size is a key predictor of reproductive success, as size is often correlated with increased gamete production. In Hymenoptera, due to haplodiploid sex determination, sperm are required to produce daughters but not sons, so sex allocation relies on a female's ability to obtain and manage a finite supply of sperm. Body size may, therefore, affect sex allocation if smaller males provide fewer sperm, or if larger, more fertile females deplete their sperm supplies by fertilizing more eggs. We examined the importance of male and female body size on offspring production and sex allocation in the parasitoid, Nasonia vitripennis (Walker). We predicted larger females would experience constrained sex allocation due to limited sperm, especially if mated with smaller males. We categorized 80 males and 80 females by size (large or small) into 4 mating groups: large females with large or small males, and small females with large or small males. We analyzed brood size and offspring sex ratios after each female oviposited on 12 pupae of Sarcophaga bullata (Parker). Overall, larger females produced more offspring and a greater proportion of males. Sex ratios became more male-biased with increased offspring production, indicating that sperm depletion had affected sex allocation in larger females. In contrast, male size did not affect sex allocation, but exhibited a small positive effect on females' offspring production. Our study highlights a complex relationship between body size, fecundity, and sex allocation, enhancing our understanding of reproductive strategies in haplodiploid organisms.

The American cockroach Periplaneta americana (L.) (Blattodea, Blattidae) has been a model organism for biochemical and physiological study for almost a century, however, its use does not benefit from the genetic tools found in key model species such as Drosophila melanogaster. To facilitate the use of the cockroach as a model system in neuroscience and to serve as a foundation for functional and translational experimentation, a transcriptome of the cephalic ganglia was assembled and annotated, and differential expression profiles between these ganglia were assessed. The transcriptome assembly yielded >400 k transcripts, with >40 k putative coding sequences. Gene ontology and protein domain searches indicate the cerebral and gnathal ganglia (GNG) have distinct genetic expression profiles. The developmental Toll signaling pathway appears to be active in the adult central nervous system (CNS), which may suggest a separate role for this pathway besides innate immune activation or embryonic development. The catabolic glycolytic and citric acid cycle enzymes are well represented in both ganglia, but key enzymes are more highly expressed in the GNG. Both ganglia express gluconeogenic and trehaloneogenic enzymes, suggesting a larger role of the CNS in regulating hemolymph sugar homeostasis than previously appreciated. The annotation and quantification of the cephalic ganglia transcriptome reveal both canonical and novel pathways in signaling and metabolism in an adult insect and lay a foundation for future functional and genetic analysis.

The predaceous fly Neoditomyia farri Coher is currently regarded as having an unknown population distribution in Jamaica. The larvae are known for their production of sticky "fishing lines" that are covered in adhesive droplets for prey capture and hang down from cave walls and ceilings. Published research beyond early observational records of the species is limited to one site-Dromilly Cave in the parish of Trelawny. The Jamaican Caves Organisation has observed larvae of the species at 26 caves visited over the last 2 decades and compiled a database with details of approximate numbers, internal and external environmental conditions, and accurate positions. Based on these records, we present evidence that the species is not cave obligate and describe factors that may suggest potential additional sites where the species can be found. Taken together, our observations paint a picture of a species which is ubiquitous and not under discernible threat, making it an excellent candidate for further research on its unique life history and behavior, which remain poorly understood.

Ecological disturbance can promote or reduce community biodiversity depending on its severity. Beekeeping activities represent a type of ecological disturbance when large numbers of honey bees are introduced to a landscape and interact with the local plant and pollinator community. In this study, we characterized the effect of immediate and long-term low-density migratory beekeeping on the diversity and abundance of native bees in the Qinghai-Tibet Plateau (China). We found that the presence of apiaries and the number of honey bees reduced native bee abundances in the local bee community, likely through displacement from floral resources. However, in locations where apiaries were previously kept for decades but are not currently present, native bee abundances recovered, and phylogenetic diversity increased; yet community relative abundances and dominant species were distinct from those that had never been stocked. Our results suggest that the presence of a transient, intermediate number of migratory honey bee colonies (60-100 colonies spaced ≥15 km from each other) may represent an intermediate ecological disturbance and not permanently reduce native bee abundances past a critical threshold that may lead to local extirpation. Yet, our study demonstrates the potential for even intermediate-scale low-density beekeeping to alter native bee communities in the long-term.

Honey bees and other pollinators face threats from pesticides, imperfect nutrition, and a diverse set of parasites and pathogens. Honey bees are also a research model for development, social behavior, microbiology, and aging. Tackling these questions requires a mix of in-hive and controlled laboratory experiments. We have perfected small-scale, inexpensive, disposable, and rearing arenas for honey bees that have proved useful for hundreds of bioassays with thousands of bees. We describe those arenas here, show their advantages over current hoarding cages, and provide videos demonstrating their many uses.

Many species are experiencing drastic and multidimensional changes to their environment due to anthropogenic events. These multidimensional changes may act nonadditively on physiological and life history responses, and thus may not be predicted by responses to single dimensional environmental changes. Therefore, work is needed to understand species' responses to multiple aspects of change. We used whole-transcriptomic RNA-Sequencing and life history assays to uncover responses to singly-applied shifts in resource or temperature environmental dimensions, in comparison to combined, multidimensional change, in the crop pest seed beetle, Callosobruchus maculatus. We found that multidimensional change caused larger fecundity, developmental period and offspring viability life history changes than predicted by additive effects of 1-dimensional changes. In addition, there was little overlap between genes differentially expressed under multidimensional treatment versus under altered resource or temperature conditions alone. Moreover, 115 genes exhibited significant resource × temperature interaction effects on expression, including those involved in energy metabolism, detoxification, and enhanced formation of cuticle structural components. We conclude that single dimensional changes alone cannot determine life history and transcriptomic responses to multidimensional environmental change. These results highlight the importance of studying multidimensional environmental change for understanding the molecular and phenotypic responses that may allow organisms including insects to rapidly adapt simultaneously to multiple aspects of environmental change.

The genus Merodon Meigen (Diptera: Syrphidae) is one of the most species-rich hoverfly genera distributed across the Palaearctic and Afrotropical regions. In the Palaearctic, the genus Merodon boasts 195 described species, while its Afrotropical region pales in comparison, with a mere 17 species documented thus far. As a result of 8 years of fieldwork conducted in the Republic of South Africa, in this paper, we present the description of 11 new species for science with a description of immature stages for 2 species, which increases the diversity of this genus in the Afrotropical region by remarkable 39%. These revelations are based on integrating morphology, molecular analysis (COI gene and 28S rRNA) and geometric morphometry. All described species belong to the Merodon planifacies subgroup, the Merodon desuturinus lineage and, within that, to the Afrotropical Merodon melanocerus group. Additionally, we provide an illustrated key to 15 species belonging to the subgroup, a detailed discussion on relevant taxonomic characters, a morphological diagnosis, a distribution map and clarification of the association between M. capi complex and host plants from the genus Merwilla.

Outdoor spatial mosquito repellents, such as mosquito coils or heating devices, release pyrethroid insecticides into the air to provide protection from mosquitoes within a defined area. This broadcast discharge of pyrethroids into the environment raises concern about the effect on non-target organisms. A previous study found that prallethrin discharged from a heating device did not affect honey bee (Apis mellifera L.) [Hymenoptera: Apidae] foraging or recruitment. In this second study, there was no significant difference in foraging frequency (our primary outcome), waggle dance propensity, or persistency in honey bees collecting sucrose solution between those exposed to metofluthrin from a different heating device and bees exposed to a non-metofluthrin control. One measure, waggle dance frequency, was higher in the metofluthrin treatment than the control but this outcome was likely a spurious result due to the small sample size. The small particle size of the emissions, averaging 4.43 µm, from the heated spatial repellent products, which remain airborne with little settling, may play an important role in the lack of effect found on honey bee foraging.