Insects最新文献

During a late-winter field survey in Baihuashan National Nature Reserve, Beijing, several noctuid moths were observed flying during the daytime at low temperatures and being actively preyed upon by Marsh tits, which removed the heads and wings of captured individuals. These observations indicate that adults of this noctuid lineage are active in late winter, providing a critical nutritional resource for insectivorous birds during the ecologically constrained, food-limited winter period. Here, we formally describe this lineage as a new genus, Shoudus gen. nov., based on a new species, S. baihuashanus sp. nov., collected from Baihuashan reserve, including three specimens retrieved during active interception of tit predation, along with detached wings and heads recovered from the snow. The new genus is placed in the tribe Orthosiini Guenée, 1837, primarily based on adult external morphology, including large compound eyes with long interfacetal hairs and bipectinate male antennae, as well as forewing patterning similar to certain orthosiine genera such as Perigrapha and Clavipalpula. Notably, the dark reddish-brown forewings with sharply contrasting pale markings, as seen in the new genus and these related genera, appear well adapted for camouflage against bark, leaf litter, and exposed soil in their habitats-potentially functioning as both background matching and disruptive coloration. To further assess its phylogenetic placement, we conducted a molecular analysis based on mitochondrial COI sequences (13 newly generated and 6 retrieved from BOLD/NCBI). The resulting maximum likelihood and Bayesian trees consistently support the monophyly of the new genus and reveal a close phylogenetic relationship with Orthosia, the type genus of Orthosiini. This integrative evidence strongly supports the recognition of Shoudus as a distinct lineage within Orthosiini.

Laodelphax striatellus is one of the most destructive rice pests. However, the functions of TARs in rice pests remain largely unknown. Here, we cloned LsTAR1 from L. striatellus. LsTAR1 shares considerable sequence identity with its orthologous receptors, and clusters closely with its corresponding receptor groups. LsTAR1 was most highly expressed in the egg stage and brain of L. striatellus. Knockdown of LsTAR1 by RNA interference (RNAi) prolonged the preoviposition and oviposition period, and reduced the fecundity. Furthermore, LsTAR1 knockdown significantly decreased the mRNA levels of vitellogenin (LsVg) in the fat body and ovary, and increased the transcript levels of Vg receptor (LsVgR) in the ovary, as well as altered the expression levels of genes related to juvenile hormone (JH) and 20-hydroxyecdysone (20E) pathway. Additionally, LsTAR1 knockdown markedly reduced the honeydew excretion of the adults and affected the expression of neuropeptide signaling genes involved in insect feeding. Notably, disruption of LsTAR1 signaling via RNAi or an antagonist reduced the survival rates of L. striatellus. This study uncovers the crucial roles of LsTAR1 in reproduction, feeding, and survival in L. striatellus, and highlights its potential as a promising target for developing novel pest management strategies.

Chitinases are crucial in the molting process of insects and represent potential targets for the development of RNA interference (RNAi)-based insecticidal strategies. In this study, we identified and characterized 11 chitinase genes (TaChts) in T. absoluta, each harboring at least one GH18 catalytic domain. Phylogenetic analysis placed these proteins into 11 established groups (I-X and h), revealing conserved lineage-specific patterns. Spatiotemporal expression profiling showed that most TaChts peak during key developmental transitions. TaCht1, TaCht2, TaCht3, TaCht5, TaCht6, TaCht7, TaCht10, TaCht-h, and TaIDGF were predominantly expressed in the integument, whereas TaCht8 and TaCht11 showed gut-enriched expression, indicating functional specialization. Stage-tailored RNAi assays demonstrated that silencing TaCht5, TaCht7, TaCht10, and TaIDGF caused pronounced mortality in both larvae and pupae. In larvae, delivery of dsRNA using carbon quantum dots (CQDs) disrupted molting: knockdown of TaCht7, TaCht10, and TaIDGF prevented shedding of the old cuticle, whereas TaCht5 silencing produced severe cuticular shrinkage and blackening. Hematoxylin and eosin staining revealed detachment of epidermal cells from the cuticle, providing cytological evidence of disrupted cuticle-epidermis remodeling. In pupae, microinjection of dsRNA induced cuticular collapse, melanization, and eclosion failure due to persistent adhesion of the pupal case, accompanied by marked reductions in chitinase activity. Together, our findings highlight the critical roles of four key chitinases in endocuticular turnover and metamorphic progression in T. absoluta, offering mechanistic insight into chitin-mediated developmental processes. The identified genes represent strong candidates for RNAi-based, species-specific pest management strategies against this globally significant insect.

The use of acoustic communication and the relatively small antennae possessed by cicadas has led to the suggestion that antennal functions, specifically olfaction, are poorly developed in cicadas. The first step in determining antennal functions is to investigate the fine antennal structure. Scanning electron microscopy was used to visualize the morphology of the antennal sensilla in a diverse group of North American cicadas. The sensilla types and their distribution on the antennae of 30 species representing 12 genera, 6 tribes, and 3 subfamilies of North American cicadas are described and/or illustrated. Seven main classes and several subclasses of antennal sensilla were found: sensilla trichodea, sensilla chaetica, sensilla coeloconica, sensilla styloconica, foramina olfactoria, sensilla campaniformia, and sensilla cavitata-peg. Unique sensilla types and/or organizations of sensilla were found in many of the genera and differences between species of some genera were also present. No sexual dimorphism within species was found in the types or organizational patterns of the sensilla. The diversity of sensilla provides additional data for taxonomy and phylogenetic analyses. The potential function of the various sensilla types is hypothesized. Although relatively small, the antennae of cicadas are likely to provide significant information about their environment and increase their survival, including the selection of specific host plants and microhabitat selection observed in many species.

In Europe, due to reduced availability and efficacy of active ingredients, strategies against grapevine pests based on alternative tools to synthetic pesticides need to be developed. So far, attention has been mainly focused on biological control (arthropod natural enemies and entomopathogens) and mating disruption, but other means can also help keep pests below economic injury levels. This paper aims to review information on the direct effects of farmers' choices on grapevine pest populations, ranging from vineyard design (e.g., growing habitat, grapevine cultivar, and training system) to annual agronomic practices (e.g., fertilization, irrigation, and pruning), and specific cultural and physical methods. Information was based on the CABI Digital Library, websites and books on grapevine pests. The data presentation is based on control strategies rather than pests, as it was considered more important to focus on the mode of action of different practices and to know which pests they affect simultaneously. The widespread availability of insecticides has long led to the neglect of the potential of cultural practices, which can effectively integrate other pest control tools.

The predatory mite Neoseiulus womersleyi is a key natural enemy in Integrated Pest Management (IPM), but its efficacy is threatened by non-target effects of acaricides like pyridaben. This study evaluated the transgenerational sublethal effects of pyridaben (LC₃₀ and LC₅₀) on N. womersleyi and explored the role of vitellogenin (Vg) genes. Using two-sex life table analysis, we found that exposure reduced longevity, fecundity, and oviposition period in F₀ females, while prolonging immature development and suppressing population growth parameters (r, λ) in F₁. Two Vg genes (NwVg1 and NwVg2) were cloned and characterized; their expression was significantly downregulated by pyridaben. RNAi-mediated silencing of NwVg1 or NwVg2 recapitulated the pyridaben-induced reproductive impairments, confirming their functional role. Our results demonstrate that pyridaben imposes multigenerational costs and that its reproductive toxicity is mediated, at least in part, through the suppression of Vg synthesis.

The rapid evolution of insecticide resistance in Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) threatens effective pest management in key crops. This study characterized B. tabaci populations from cotton and tomato fields in Kashgar (September-October 2024) using mtCOI-RFLP for cryptic species identification, leaf-dip bioassays with 13 insecticides, and PCR detection of tomato yellow leaf curl virus (TYLCV). All analyzed individuals belonged to the Mediterranean (MED) cryptic species. Extreme resistance was observed to imidacloprid (RR = 320.65) and pyridaben (RR = 331.29), while nitenpyram (RR = 1.77) and the emamectin benzoate-chlorantraniliprole mixture (RR = 2.13) remained effective. TYLCV was detected in 97.5% of adults from tomato greenhouses. These findings provide a concise assessment of resistance status, species identification, and virus prevalence in B. tabaci, informing sustainable management strategies in cotton and tomato production.

The fall armyworm (FAW), Spodoptera frugiperda, poses a major threat to global maize production. Reliance on synthetic pesticides has contributed to pest resistance and environmental degradation, underscoring the need for sustainable alternatives. In this study, ethanolic extracts of neem (Azadirachta indica) and moringa (Moringa oleifera), together with maize-associated bacterial isolates, were evaluated for their biocontrol potential against fall armyworm. Gas chromatography-mass spectrometry (GC-MS) analysis for bioextract identification revealed tissue-specific chemical diversity, identifying eight key phytochemicals, including octadecanoic acid, trimethyl fluorosilane, and hexadecanoic acid in neem, and trimethyl fluorosilane, ethyl oleate, ethyl (9Z,12Z), octadecanoic acid, and benzenedicarboxylic acid in moringa extracts. Eighty-nine bacterial isolates were screened for extracellular enzyme activities (cellulase, chitinase, glucanase, and protease) and siderophore production, among which four strains, DR-55 (Bacillus subtilis), HL-7 (Bacillus cereus), HL-37 (Bacillus cereus), and DR-63 (Enterobacter sp.), exhibited >50% biocontrol efficacy under greenhouse conditions. A strong correlation (r = 0.88) was observed between in vitro antagonistic activity and greenhouse performance, validating the screening approach. Fall armyworm mortality was the highest in larvae (up to 80%), moderate in pupae (15-17%), and the lowest in adults (6-7%), respectively. Overall, plant bio-extracts and maize-associated microbial isolates represent a promising, non-hazardous strategy for sustainable fall armyworm management while preserving maize plant health.

Rice is a key food crop worldwide, but its yield and quality are severely constrained by insect pests. As environmental and regulatory restrictions on chemical pesticides grow, developing insect-resistant rice varieties has become a sustainable way to protect food security. This review covers recent progress in functional genomics and molecular marker mapping related to insect resistance in rice. We highlight the identification, cloning, and functional analysis of resistance genes targeting major pests, including the brown planthopper, rice gall midge, white-backed planthopper, small brown planthopper, and rice leaf roller. Several important resistance genes (such as Bph14, Bph3, and Bph29) have been cloned, and their roles in rice immunity have been clarified-covering insect feeding signal recognition, activation of salicylic acid and jasmonic acid pathways, and regulation of MAPK cascades, calcium signaling, and reactive oxygen species production. We also discuss how molecular marker-assisted selection, gene pyramiding, and transgenic techniques are used in modern rice breeding. Finally, we address future challenges and opportunities, stressing the importance of utilizing wild rice germplasm, understanding insect effector-plant immune interactions, and applying molecular design breeding to create long-lasting insect-resistant rice varieties that can withstand changing pest pressures and climate conditions.

Spodoptera frugiperda is a major agricultural pest both in Brazil and worldwide, with widespread resistance to synthetic insecticides. This study evaluated the toxicity and residual activity of toxic bait formulations combining 17 insecticides with the plant-based kairomone attractant Noctovi^® 43SB against S. frugiperda adults. Bioassays were conducted with 48 h-old, food-deprived adults. Toxicity was assessed by incorporating insecticides at 2% concentration into Noctovi^® 43SB. Residual activity was measured by applying toxic baits on cotton leaves and testing at 3, 7, 15, 21, and 30 days after application (DAA). Insecticides based on methomyl, spinetoram, spinosad, indoxacarb, malathion, and zeta-cypermethrin induced over 95% mortality. Methomyl showed the greatest toxicity (LC₅₀ = 322 mg a.i. L^-1; LC₉₀ = 1160 mg a.i. L^-1). Eleven insecticides maintained residual activity (≥70%) after 30 DAA, except malathion. Overall, toxic bait formulations combining Noctovi^® 43SB with methomyl, spinosad, spinetoram, or indoxacarb proved highly effective, offering both rapid and prolonged control of S. frugiperda adults. These findings highlight attract-and-kill as a promising tool for sustainable management of this pest.