Journal of Insect Science最新文献

Species spread in a new environment is often associated with founders' effect, and reduced effective population size and genetic diversity. However, reduced genetic diversity does not necessarily translate to low establishment and spread potential. Paracoccus marginatus Williams and Granara de Willink is a polyphagous pest that has invaded 4 continents in around 34 years. It was first detected in the Northern Territory, Australia in July 2023. Following this, we collected 45 specimens from 20 suburbs across 3 regions. Using mitochondrial cytochrome oxidase I and nuclear ribosomal RNA genes (18S and 28S), we examined molecular diagnostics robustness, genetic diversity, haplotype network, and demographics (Tajima D) of the recently detected Australian population. We compared our samples with publicly available sequences deposited on GenBank. All 3 genes were suitable for molecular diagnosis with a 100% identity score. For all 3 genes, we found low nucleotide diversity, haplotype diversity, and negative Tajima D in the newly detected P. marginatus population, suggesting a recent single founder event by a few individuals. Comparing our study's sequences with global sequences showed low haplotype diversity, nucleotide diversity, and Tajima's D, suggesting that despite low genetic diversity at the 3 genes, P. marginatus has successfully invaded South America, Africa, Asia, and Oceania. Our study highlights the role of demographic and life history traits in the species' invasion success. We provide a baseline dataset from the first detection of P. marginatus in Australia. Further analysis of the spread can provide insights into invasive species' adaptation in a novel environment.

The role of flood and drought stress on Xylosandrus ambrosia beetle attacks and colonization in nursery trees with varying levels of water stress tolerance has not yet been studied. This study aimed to examine ambrosia beetle preference for tree species varying in their tolerance to water stress. Container-grown dogwoods, redbuds, and red maples were exposed to flood, drought, or sufficient water treatments for 28 d and beetle attacks were counted every third day. Stem tissues were collected at 7 and 14 d after imposing water stress to measure ethanol content using SPME-GC-MS. Trees were dissected to record gallery formation, fungal colonization, presence of eggs, larvae, and adults within the gallery. Additionally, gallery depth was measured. Under flood stress, beetle attacks were found exclusively in dogwood and redbud, with no attacks in red maple. There was a higher number of attacks in dogwood compared to redbud. Gallery formation and depth, fungal colonization, and presence of eggs, larvae, and adults in galleries were higher in dogwood than redbud. About 85% of the adults recovered from galleries were X. crassiusculus and the rest were X. germanus. Among the trees subjected to drought stress, only one dogwood tree had attacks, while the redbuds and red maples had no beetle attack. Tree species assigned to sufficient water were not attacked. Higher ethanol content was detected in dogwood and redbud subjected to flood stress compared to flooded red maples and tree species assigned to drought and sufficient water. This understanding can help growers and landscapers in making informed management decisions.

The Lepidopteran pest Trichoplusia ni and the parasitoid wasp Trichogramma brassicae represent a fascinating biological system, important for sustainable agricultural practices but challenging to observe. We present a nondestructive method based on micro-CT scanning technology (CT: computed tomography) for visualizing the internal parts of caterpillar embryos and of emerging parasitoids from infected eggs. Traditional methods of microscopic observation of the opaque egg contents require staining or dissection. To explore the biological system nondestructively, we optimized the application of micro-CT scanning to construct 3-D images of insects in vivo.

House flies, Musca domestica L., are pests at livestock facilities. House fly numbers are controlled mainly by manure management and chemical controls, like use of toxic baits. Some toxic baits contain denatonium benzoate as a bittering agent, to avoid poisoning of children. House fly behavioral response to denatonium benzoate was examined, using 2 different diluents, sucrose solution or orange juice. Response of flies to quinine and sucrose octaacetate, 2 other bittering agents, was also examined in sucrose. Sucrose is the sweetener in commercially available toxic house fly baits. The proboscis extension response of both male and female flies was significantly reduced by addition of 1,000 ppm of denatonium benzoate to sucrose. Response in males was also reduced at 100 ppm. Consumption of sucrose by both male and female flies was reduced by addition of 100, 500, and 1,000 ppm of denatonium benzoate, but consumption by males was also reduced at 10 ppm. Addition of sucrose octaacetate had no detectable effect on consumption of sucrose at 100, 500, or 1,000 ppm. In contrast, addition of quinine reduced consumption by both male and female flies in all tested concentrations. In orange juice, 10 ppm of denatonium benzoate is often avoided by children. With orange juice, fly proboscis extension response patterns were the same for both sexes, with a reduction at 1,000 ppm of denatonium benzoate. Orange juice consumption by flies was reduced significantly at 1,000 ppm of denatonium benzoate for females but not at any of the concentrations tested for males.

Mitochondrial genomes are a rich source of data for various downstream analyses such as population genetics, phylogeny, and systematics. Today it is possible to assemble rapidly large numbers of mitogenomes, mainly employing next-generation sequencing and third-generation sequencing. However, verification of the correctness of the generated sequences is often lacking, especially for noncoding, length-variable parts. Here we have assembled the mitochondrial genome (mitogenome) from four specimens of Agabus bipustulatus (L.) using long-read nanopore sequence data. The use of the latest nanopore chemistry (V14) combined with a comprehensive error correction workflow enabled the generation of mitogenomes with high accuracy and reproducibility, as tested on four samples. The resulting mitogenome is 17,876 bp long, including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region. Differences in the control region length between samples were minimal. The arrangement of protein-coding genes, transfer RNAs, and ribosomal RNAs is similar to that of the ancestral insect mitogenome. Finally, we used the assembled, well-supported mitogenomes in the phylogenetic analysis of a part of the Dytiscidae related to the studied species and confronted the results with previous hypotheses. Conflicting estimates of their phylogeny suggest that considerably more robust data are required for a plausible sketch of their evolutionary history. Our research has confirmed that readily available third-generation sequencing technologies, such as Oxford Nanopore Technologies, combined with long-read sequencing, offer a highly efficient, reliable, and cost-effective approach to generate complete mitogenomes and potentially other longer regions of the genome. The use of reliable data will ultimately contribute to a deeper understanding and improved conservation strategies for diving beetles and other organisms.

Insects perceive and respond to carboxylic acids (CAs), amines, and aldehydes primarily via conserved ionotropic receptors (IRs). These receptors form the basis for a second olfactory system distinct from the well-characterized odorant receptors. Neurons expressing IRs are housed in dedicated sensilla and innervate glomeruli, separate from those innervated by odorant receptor neurons. The IR8a co-receptor is highly conserved across insect orders and, together with ionotropic receptor tuning receptors, primarily detects CAs. The conservation of genes and the anatomical separation of neural pathways underscore the importance of these compound classes and CAs, specifically in insect chemical ecology. We provide a summary of carboxylic acid detection in insects, focusing on dipteran and lepidopteran species of significance to public health and agriculture. An overview of insect behavior toward CAs is provided, as well as a comprehensive update on carboxylic acid receptor function in insects. Phylogenetic analysis of publicly available genome databases reveals several species that encode and express homologs of previously deorphanized carboxylic acid receptors, highlighting avenues for future research.

Radio frequency identification (RFID) technology and marker recognition algorithms can offer an efficient and non-intrusive means of tracking animal positions. As such, they have become important tools for invertebrate behavioral research. Both approaches require fixing a tag or marker to the study organism, and so it is useful to quantify the effects such procedures have on behavior before proceeding with further research. However, frequently studies do not report doing such tests. Here, we demonstrate a time-efficient and accessible method for quantifying the impact of tagging on individual movement using open-source automated video tracking software. We tested the effect of RFID tags and tags suitable for marker recognition algorithms on the movement of Argentinian wood roaches (Blapicta dubia, Blattodea: Blaberidae) by filming tagged and untagged roaches in laboratory conditions. We employed DeepLabCut on the resultant videos to track cockroach movement and extract measures of behavioral traits. We found no statistically significant differences between RFID tagged and untagged groups in average speed over the trial period, the number of unique zones explored, and the number of discrete walks. However, groups that were tagged with labels for marker recognition had significantly higher values for all 3 metrics. We therefore support the use of RFID tags to monitor the behavior of B. dubia but note that the effect of using labels suitable for label recognition to identify individuals should be taken into consideration when measuring B.dubia behavior. We hope that this study can provide an accessible and viable roadmap for further work investigating the effects of tagging on insect behavior.

Asian longhorned beetle (Anoplophora glabripennis Motschulsky), a wood borer (Coleoptera: Cerambycidae) native to China, has been unintentionally and repeatedly introduced to North American and European landscapes as a stow-away in the wood packing material commonly used in international trade. Asian longhorned beetle causes extensive damage and mortality in multiple deciduous tree species and in response, countries in both North America and Europe have adopted policies of eradication. Models that integrate patterns of Asian longhorned beetle dispersal with records of infested trees are critical in optimizing survey and eradication efforts and tracking eradication progress. While these tools continue to be developed, they have been limited by the availability of experimental dispersal data. Existing data is restricted to observations made in the beetle's native range in China or based on inference of dispersal in invaded landscapes. Direct observation of beetle dispersal behavior in invaded landscapes could provide critical behavioral information, but the experimental release of gravid females has been incompatible with eradication program efforts. To fill this knowledge gap, there is a need to identify field-portable methods of effectively sterilizing mated females that do not alter ovipositional behavior. Here, we present a protocol for cauterizing a beetle's ovipositor to prevent successful oviposition. Results of lab trials demonstrate the efficacy of ovipositor cauterization in inhibiting successful oviposition without altering the egg-laying behavior of gravid Asian longhorned beetle females. This method enables research to inform models of beetle dispersal and infestation risk without adding to actual or perceived risk of exacerbating infestations in an eradication program.

The granulate ambrosia beetle, Xylosandrus crassiusculus (Motschulsky), and the black stem borer, Xylosandrus germanus (Blandford) are important pests in ornamental nurseries in the eastern USA. These beetles are managed mainly using preventative trunk applications of pyrethroids, such as permethrin or bifenthrin when females typically fly out of woodlots and attack young trees in the spring. Verbenone and methyl salicylate are potential phytochemicals reported as repellants but not completely validated in ornamental nurseries for ambrosia beetle management as an alternative option. Thus, this study aimed to compare the efficacy of verbenone alone or with methyl salicylate and permethrin on ambrosia beetle attacks. In 2023 and 2024, a study was conducted where verbenone (with methyl salicylate) and permethrin were combined with 10% and 50% ethanol-infused maple bolts. Verbenone alone or combined with methyl salicylate did not reduce ambrosia beetle attacks on bolts compared to permethrin. Permethrin was effective in reducing ambrosia beetle attacks on bolts. This suggests that permethrin is still the best option to prevent ambrosia beetle attacks on young trees in ornamental nurseries.

Navel orangeworm, Amyelois transitella (Walker), is a key pest in California's almonds, pistachios, and walnuts. This insect's strong dispersal capacity can potentially undermine the efficacy of localized management efforts. The timing and extent of A. transitella movement between orchards remain unclear, and more studies are needed to better characterize its landscape ecology. Mark-release-recapture studies offer a potential solution but require a reliable insect marker that is durable, easily identifiable and has minimal impacts on A. transitella longevity and flight ability. To address this, we evaluated 4 colors (red, blue, green, and yellow) of a fluorophore marker (SmartWater) for adult A. transitella. We conducted laboratory assays to assess moth flight ability and mortality, as well as marker persistence over time using both quantitative (plate reader) and qualitative (visual observation) fluorophore detection methods. Results demonstrated that none of the 4 colors negatively affected A. transitella flight ability or mortality. Green and yellow markers were persistent and readily identified by both detection methods, unlike blue and red markers. Although marker degradation was observed over time with the quantitative method, a high percentage of moths (70.3%) retained green and yellow markers after 14 days. In contrast, these markers did not show significant degradation using the qualitative method, with over 94.2% of moths showing fluorescence 14 days postmarking. These findings highlight the strong potential of green and yellow markers for field studies with A. transitella. We discuss their use in future mark-release-recapture studies and compare the 2 fluorophore detection methods.