Archives of Insect Biochemistry and Physiology最新文献

Mosquitoes spread a range of life-threatening illnesses such as malaria, dengue, zika virus, chikungunya, yellow fever, and many others, and cause up to 1 million deaths and 1 billion infections across the world every year. There has been growing interest in plant-based repellents that display bioactive compounds with insecticidal and repellent activities. In this review, the focus is on a natural monoterpene that has gained therapeutic properties, including antifungal, antibacterial, antioxidant, anticancer, and neuropharmacological activity, including anti-anxiety and sedative activity. The efficacy of linalool was assayed against mosquitoes in larvicidal and repellent bioassays. Larvicidal assays exhibited dose-dependent mortality: 82% at 1%, 87.4% at 2%, and 90.8% at 4% concentration after 24 h. Repellency cage assays exhibited good initial efficacy, with 1% linalool repelling 82.2% of mosquitoes, 2% repelling 81.8%, and 4% repelling 90.8%, very close to DEET's (N,N-diethyl-meta-toluamide) 93.4%. After 210 min, the 4% concentration had 82.2% repellency, while DEET had 89.6%. Tunnel tests revealed 4% linalool provided 90.2% repellency at 1 h and 84% at 3 h. The findings show that linalool, especially at high levels, is extremely effective as a repellent and larvicide. Its activity is as effective as that of DEET, the present synthetic repellent, and hence linalool can be utilized as an effective natural substitute for long-lasting mosquito control.

The taxon Paraneoptera, comprising Condylognatha (Hemiptera e Thysanoptera) and Psocodea (Phthiraptera and Psocoptera), is paraphyletic, according to recent genomic studies. The midgut morphology and digestive physiology of Haematopinus suis (Phtiraptera) are described here and compared with similar data from Hemiptera and Holometabola. H. suis (Phtiraptera) midgut cells, in contrast to Hemiptera, lack microvillar-associated membranes and have a digestive enzyme secretory mechanism of the type microapocrine, like many Holometabola. Also, like Holometabola, and different from Hemiptera, the main endopeptidases of H. suis are serine endopeptidases (trypsin and chymotrypsin), instead of cysteine endopeptidases. The major difference of H. suis in relation to Holometabola is the absence of a peritrophic membrane (PM), thought to be a consequence of the fact of PM cost of production in this minute insect out weights the benefit of midgut compartmentalization. Our data favor the view that Phthiraptera is closer to Holometabola than to Hemiptera, agreeing with the alleged paraphilia of Paraneoptera.

Honey bees, as indispensable pollinators, can promote agricultural production and maintain ecological balance. Because of honey bees' eusociality, studying honeybee colonies is of great importance. RNA interference (RNAi) has emerged as a powerful tool for honey bee research. However, the application of RNAi in honey bee colonies is frequently impeded by challenges related to the efficient delivery and mass synthesis of dsRNA. In this study, we developed a novel field-based RNAi method for Apis mellifera ligustica Spinola (Hymenoptera: Apidae) colonies by feeding them nanomaterial-encapsulated dsRNA (SPc-loaded dsRNA) synthesized using the pET28-BL21(DE3) RNase III- system. Firstly, we demonstrated that A. mellifera preferred honey solutions containing ultrasonically disrupted E. coli to the original solutions. Secondly, we found that SPc not only effectively protected dsRNA from degradation by honey bee intestinal fluids but also enhanced RNAi efficiency. Finally, we observed a significant reduction in target gene expression levels after implementing RNAi in small hives equipped with automatic feeders, by delivering SPc-loaded dsRNA in a field setting. This is an innovative method to implement RNAi on honey bee colonies based on E. coli and the SPc in the field. The approach provides valuable insights into dsRNA synthesis for honey bees and RNAi implementation in honey bee colonies. This approach holds promise for promoting honey bee research on colony level, ultimately contributing to ecological balance and biodiversity.

Bemisia tabaci MED is one of the major cryptic species that infests various horticultural crops. Over the years, insecticide resistance has developed in this species due to overuse, yet there is a lack of research on resistance rates among individual insecticides. In this study, the age-specific effects of eight insecticides with different modes of action (acetamiprid [4a], flupyradifuron [4b], spinetoram [5], emamectin benzoate [6], pyrifluquinazon [9b], pyridaben [21a], spiromesifen [23], cyantraniliprole [28]) were tested on B. tabaci eggs of different ages. Insecticides at different doses were applied to eggs on tomato plants via leaf dipping assays, and the mortality until shortly after hatching (1st instar nymphs) was determined. Among the tested compounds, pre-hatch mortality was substantially higher for neonicotinoid compounds (55.8 ± 3.8% and 88.6% ± 4.7% for flupyradifuron and acetamiprid, respectively), hatch failure was greatest for pyridaben (57% ± 6.5%), and 1st instar nymph mortality was higher for emamectin benzoate (74.1% ± 7.9%), pyrifluquinazon (69.9% ± 2.5%), cyantraniliprole (67.9% ± 7.5%), and spinetoram (66.6% ± 3.3%). This suggests that neonicotinoids are highly lethal at the embryonic stage, while pyridaben induced hatch failure, and a variety of other insecticides induced lingering lethality after hatching. Our results provide essential information for understanding each insecticide's developmental and physiological effects and improving the chemical control of B. tabaci.

The prevalent environmental contaminant cadmium threatens ecosystems, yet the lack of high-resolution behavioral kinematics hinders assessment of cadmium neurotoxicity in ecologically critical insect larvae. This study integrated machine learning-based trajectory tracking methodologies, to meticulously quantify dose-dependent effects of cadmium on the locomotion velocity, angular velocity, directional preference, and trajectory alterations, using Drosophila larvae as a model organism. Results demonstrated that cadmium exposure not only increased the larval movement speed and the proportion of active duration but also substantially diminished the angular velocity and the duration of high angular velocity. Notably, the average speed curve among the cadmium treatment groups exhibited a “U”-shaped distribution. At a lower concentration (1 mg/L), an increase in speed and the duration of straight movement were prominent. The medium concentrations (4 and 8 mg/L) were characterized by the highest trajectory complexity and the largest individual disparities, respectively. Despite the enhanced activity at the high concentration (16 mg/L), there was a concurrent increase in movement complexity. These behavioral changes are likely related to factors such as neurotransmitter regulation, visual damage, and antioxidant mechanisms. This study not only reveals the complex effects of cadmium on the movement behavior of insects, but also provides a reference basis for the research on the neurotoxic mechanism of cadmium on organisms and the assessment of the ecological risks of heavy metal pollution.

To investigate the functional role of the nicotinic acetylcholine receptor (nAChR) α6 subunit in Megalurothrips usitatus and its involvement in insecticide resistance, we cloned the nAChR α6 gene (Muα6) using RACE technology and analyzed its spatiotemporal expression patterns via RT-qPCR. Functional studies were further conducted under spinetoram stress. The results showed that Muα6 (GenBank accession: PQ441948) has a full-length sequence of 1569 bp, encoding 523 amino acids with four transmembrane domains (TM1-TM4), six extracellular loops (Loop A-F), and two N-glycosylation sites (Asn100 and Asn144). Multiple sequence alignment revealed 95.53% similarity between Muα6 and the α6 subunit of Frankliniella occidentalis (AOT81842.1). Alternative splicing analysis identified four isoforms (3a8a/3a8b/3b8a/3b8b), with 3b8a being the dominant type (58.3%). Spatiotemporal expression profiling demonstrated the highest Muα6 expression in pupae and the lowest in second-instar nymphs. In adults, Muα6 expression in the abdomen was significantly lower than in the head and thorax. After 48 h exposure to spinetoram (LC₅₀ = 1.243 mg·L⁻¹), Muα6 expression was significantly upregulated to 2.05-fold the control level (p < 0.05). This study is the first to elucidate the molecular characteristics and expression regulation of the Muα6 in M. usitatus. The insecticide-induced upregulation suggests its potential role in target-site resistance, providing a theoretical basis for understanding the mode of action of spinosyns and guiding field resistance management strategies.

Bumblebees are a group of approximately 265 species of large-bodied bees adapted to cold climates, widely distributed in diverse regions like subarctic, temperate, subtropical, and tropical areas. However, the decline in bumblebee populations and induced risks in pollination services has stimulated growth in related research. This study conducted a comprehensive bibliometric analysis of bumblebee research over four decades (1980–2024), tracing its historical evolution, current hotspots, and emerging trends. Key findings reveal a consistent increase in both publications and citations related to bumblebees over the past four decades. A total of 1005 scholarly journals published articles on the application of bumblebees, with 200,185 co-citation counts. The United States, the United Kingdom, and several European countries are at the forefront of bumblebee research, with major institutions such as University of California System contributing significantly to the field. The analysis identifies emerging research hotspots in ecology, plant, zoology and molecular biology, highlighting a shift towards interdisciplinary approaches. The analysis of authors and co-cited authors networks revealed 1398 authors contributed to the total number of papers. Dave Goulson ranks first with 160 publications and 2576 co-citations. The keyword co-occurrence network of bumblebee showed three periods, and the strongest citation burst linked to research on pollination and ecosystem services. The evolution of bumblebee research highlights ‘wild bee,’ ‘foraging distance,’ and ‘social learning’ as key emerging topics. The study identifies trends with significant implications, including a growing interest in pollinator conservation and the ecological role of bumblebees, and suggests new directions for future bumblebee research.