Journal of Insect Science最新文献

Aphids exhibit wing dimorphism: apterous morphs remain on hosts to sustain reproduction, while alates facilitate colonization of new habitats. The success of alates relies on antennal sensilla mediating olfactory cues for host location, yet such adaptations remain uncharacterized in Semiaphis heraclei (Takahashi). In this study, differences in antennal morphology between morphs were compared by scanning electron microscopy. Alates had significantly longer antennae than apterous morphs due to flagellar elongation and also uniquely had secondary rhinaria, densely distributed across flagellomeres I to III. They also had significantly larger primary rhinaria, but trichoid and campaniform sensilla showed no differences between morphs. These results indicate that antennal dimorphism underlies ecological specialization in S. heraclei: alates display enhanced sensory traits likely facilitating host detection and dispersal, while apterous morphs retain a conservative morphology. This study provides the first detailed characterization of antennal sensilla in the parthenogenetic alate and apterous morphs of S. heraclei. The morph-specific sensory adaptations we identified, particularly in olfactory sensilla, establish a morphological basis for future research aimed at developing olfaction-based pest management strategies.

The red flour beetle, Tribolium castaneum (Herbst), is a major pest of stored products. Microsatellite markers offer valuable tools for population genetic studies; however, existing markers often exhibit limited polymorphism or lack validation in field-collected populations. In this study, microsatellite loci were identified from whole-genome sequencing data of T. castaneum and tested for their utility in Malaysian populations. A total of 13.8 million sequence reads yielded 108,318 primer pairs, from which 20 markers were selected for screening. Of these, 7 loci consistently amplified and exhibited high levels of polymorphism, producing 14 to 28 alleles per locus. Expected heterozygosity values ranged from 0.798 to 0.962, and polymorphic information content exceeded 0.750 for all loci, indicating their high informativeness. Population differentiation analysis revealed moderate genetic structuring among populations (mean FSt = 0.162), suggesting restricted gene flow across sampled regions. These results demonstrate that the newly developed microsatellite markers are robust and highly polymorphic, providing a valuable resource for population genetic studies of T. castaneum and supporting efforts to understand pest dispersal and management in Malaysia.

A decline in global forest health, due in part to the spread of insect pests, has prompted research into effective, sustainable, and economically feasible solutions to manage forest pests, including the use of classical biological control. Among the top 5 imperiled tree species in North America, eastern hemlock (Tsuga canadensis (L.) Carriere) is impacted by the invasive hemlock woolly adelgid, Adelges tsugae Annand, accidentally introduced from southern Japan. Three specialist natural enemies of A. tsugae found on western hemlock woolly adelgid in western North America have been deemed promising biological control agents and approved for release-2 species of silver fly, Leucotaraxis argenticollis (Zetterstedt) and Leucotaraxis piniperda (Malloch), and a beetle, Laricobius nigrinus Fender. Supplying quantities of these predators needed for research and release has special challenges given their dietary and habitat needs. We have developed novel collection and rearing methods for producing these 3 predators simultaneously in large numbers as part of a rearing and release strategy in eastern North America.

Citizen science (CS) has been proven to be a powerful approach for biodiversity monitoring, offering large-scale and long-term data collection opportunities. This study explores the possibility of reusing images collected under a CS initiative aimed at mapping the distribution of the European stag beetle (Lucanus cervus [L.]) in Italy for ethological purposes. Volunteers contributed 2,090 photographic records and, among them, more than one-third were valid for ethological purposes. These records were analyzed to investigate specific behaviors, exploited substrate and seasonal preferences, considering specimen number and sex. Single males represent the majority of the sample, and the most represented couple is male-female. Regarding the ethological traits, the most recorded one is standing/walking for single specimens (both males and females) and reproductive behavior for couples. In addition, a sex-related seasonal variation has been observed with single individuals recorded mainly in July and couples in June. Moreover, substrate preferences indicated males' affinity for natural wood and females' inclination toward bare ground. However, the lack of detailed environmental cues limited additional behavioral insights. This being given, the present study underscores the possibility of leveraging volunteer-collected data from an existing CS initiative for ethological purposes, even if some limitations were encountered. For this reason, good practices are provided in order to ensure a broader applicability of ecological and behavioral research in current or future CS projects.

The legume pod borer, Maruca vitrata (F.) poses a significant threat to leguminous crops, necessitating sustainable management approaches to mitigate damage and maintain productivity. This study evaluated sunn hemp, Crotalaria juncea (L.) (Fabaceae), as a potential dead-end trap crop for managing M. vitrata infestations in cowpea, Vigna unguiculata subsp. sesquipedalis (L.) (Fabaceae), and lablab bean, Lablab purpureus (L.) (Fabaceae). Laboratory oviposition assays indicated that sunn hemp was significantly less preferred than cowpea in dual-choice conditions, whereas no significant preference was detected relative to lablab bean. Interestingly, sunn hemp received more eggs than cowpea under no-choice conditions but fewer than lablab bean. Larvae feeding on sunn hemp suffered complete mortality, failing to develop beyond the fourth instar. In contrast, cowpea and lablab beans equally supported complete larval and pupal development without significant differences in developmental parameters, pupal weight, or sex ratio. Field experiments demonstrated that sunn hemp effectively reduced pest infestation relative to untreated controls, showing comparable efficacy to chemical treatments. Marketable yield proportions differed significantly between the crops, with lablab bean consistently achieving higher marketable yields than cowpea. Sunn hemp significantly enhanced the marketable yield of lablab beans, reinforcing its value as a tool for ecological pest management. Overall, sunn hemp effectively disrupted M. vitrata populations, reduced pest pressure, and improved yield quality, thus highlighting its potential as a sustainable and ecologically beneficial component in integrated pest management programs for leguminous crops.

Accurate normalization of gene expression data in real-time quantitative polymerase chain reaction (RT-qPCR) relies on the identification of stably expressed reference genes, which remains uncharacterized in Pieris melete Ménétriés, a cruciferous crop pest with agricultural significance. This study systematically evaluated eight candidate reference genes (GAPDH, α-tub, β-actin, 18S, β-tub, EF1α, RPL27, RPS15) across four experimental conditions: developmental stages, tissues, temperature stresses, and diapause stages. Stability rankings were determined using four algorithms (geNorm, NormFinder, BestKeeper, ΔCt method) integrated via RefFinder. Results revealed that at different condition-specific stability patterns, RPL27 and EF1α were optimal for developmental stages, RPL27 paired with 18S were suitable for tissue analyses; EF1α and α-tub were stable at different temperature stresses, and RPL27 combined with RPS15 were stably expressed during diapause. Pairwise variation analysis confirmed that dual reference genes sufficiently enhanced normalization accuracy. This work provides the validated reference genes panel for P. melete, addressing a critical gap in molecular studies of this pest and ensuring robust gene expression analyses for future research on diapause regulation and pest control strategies.

Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) is a major pest of the Chinese honey bees. Real-time quantitative Polymerase Chain Reaction (RT-qPCR) is a stable method for quantifying gene expression, and the selection of appropriate reference genes is necessary for standardizing gene expression analysis. In this study, the expression profiles of 12 candidate reference genes (GAPDH2, TUBB2B, TBP, RPL7, RPL13, RPL22, SOD, AK1, RPS7, RPS20, RPS25, and PKG21D) were analyzed via 5 different treatments. The stability of candidate reference gene expression was assessed using geNorm, NormFinder, BestKeeper, ΔCt, and RefFinder. Significant differences in optimal reference gene combinations were observed under diverse experimental conditions. Based on different developmental stages, larval tissues, UV irradiation of males, low- and high-temperature treatments of females, high-temperature treatments of males, and insecticide applications, the most suitable reference gene combinations were RPL13 + RPS20, RPL7 + RPL13, RPL22 + RPL7, RPS7 + SOD, RPS25 + RPL22, RPL22 + RPS20, and TBP + RPS25. For UV irradiation to females and low-temperature treatment to males, the best reference gene combination was consistently identified as RPL22 + RPL13. These results laid the foundation for the standardization of RT-qPCR analysis and provided crucial support for developing targeted control strategies for the greater wax moth, such as RNA interference and gene editing, for future studies.

Protohermes species are among the top aquatic predators in benthic invertebrate communities. Their ability to perceive mechanical stimuli may be functional in mediating responses to freshwater environmental cues. In this study, we performed a transcriptome analysis of the antennae, maxillae, and labium of Protohermes xanthodes Navás larvae (Megaloptera: Corydalidae), identifying 2 transmembrane protein genes (PxanPiezo and PxanNompC), which are phylogenetically related to mechanosensory transduction channels in other insects. PxanPiezo is a large transmembrane protein featuring 38 transmembrane helices that mediate its association with the cytoplasm. PxanNompC is another transmembrane protein containing an extensive intracellular ankyrin repeat domain, a structural feature that enables potential interactions with the cytoskeleton. PxanPiezo is widely expressed in the internal tissues, such as nerve tissue, the digestive organs, the excretory organ, and the energy storage tissue, as well as in the body surface tissues, including the antennae, maxillae, labium, legs, lateral filaments, anal prolegs, and the abdominal integument. In contrast, PxanNompC exhibits tissue-specific expression in body surface structures and is highly expressed in the abdominal integument. These results suggest that PxanPiezo and PxanNompC possess the structural basis required to convert mechanical stimuli into signal currents. Their distinct structural features and expression profiles imply potential differences in their mechanoelectrical transduction mechanisms. Furthermore, identifying mechanoelectrical transduction channel genes in P. xanthodes could facilitate the studies on the sensory mechanisms of this aquatic insect adapting the freshwater environments.

Reticulitermes is a genus of subterranean termites that experienced a rapid radiation during the late Miocene, resulting in a widespread distribution across the Holarctic region. Despite decades of phylogenetic research that has delineated some well-supported lineages, relationships among them remain unresolved. Previous studies based on a handful of mitochondrial or nuclear markers have produced conflicting topologies and failed to robustly resolve deep nodes within the genus, particularly among the East European-West Asian (EE + WA) and Western Europe lineages. More recently, despite improved resolution achieved through mitochondrial phylogenomics, a major limitation in Reticulitermes studies has been the complete absence of mitochondrial genomes for the EE+WA lineage. To address this, we sequenced 6 new mitochondrial genomes from 5 Reticulitermes taxa, including the first representatives of the EE + WA clade, and analyzed them alongside previously published data. Phylogenies were inferred across a range of analytical conditions. All analyses supported the monophyly of Reticulitermes, though the placement of EE + WA varied depending on the data and model. Analysis of the nucleotide dataset recovered EE + WA as sister to all other clades. In contrast, the amino acid dataset found it nested within the genus, placing East Asia as the earliest diverging lineage. Our results underscore the sensitivity of phylogenetic inference to dataset and model choice in the context of Reticulitermes rapid radiation and provide new insights for resolving the evolutionary history of this genus. The inclusion of EE + WA fills a key geographic gap and suggests a complex history of diversification, consistent with either an ancient refugial split in southeastern Europe-Western Asia or an extraordinarily rapid westward expansion.

This study investigates the mechanisms governing the formation and transfer of microbial communities associated with the honey bee (Apis mellifera L.) superorganism, focusing on the interplay between plant, in-hive, and bee environments. By analyzing 16S rRNA sequencing data from multiple public datasets through bioinformatics and statistical modeling, we characterized the structure and transmission pathways of these microbiota. Our analysis reveals that each environment hosts a distinct and specialized microbial community, with significant barriers to free microbial exchange. Alpha and beta-diversity analyses confirmed the uniqueness of the bee gut microbiota and the mixed, intermediate nature of the honey microbiome. Structural equation modeling identified that direct microbial transfer from plants to bees is negligible. Instead, honey serves as an obligate intermediary and selective filter, with microorganisms transitioning from plants to honey before a lower-probability transfer to bees occurs. Furthermore, we identified key bacterial taxa, including Apilactobacillus kunkeei, Acinetobacter, and Pseudomonas, that potentially act as generalists capable of persisting across multiple environments. These findings underscore the possibility of the selective bacterial transfer between hives, which may play roles in both pathogens transfer and maintaining hive microbiome stability.