Insects最新文献

The global migratory pest, Spodoptera frugiperda, has garnered widespread attention due to the serious damage it inflicts on agricultural productivity, particularly in maize. Thymol is a phytochemical that exhibits functional diversification in plant defense, encompassing antibacterial activities and insect pest management. However, the impact of thymol on S. frugiperda is still undetermined. This study examined the growth inhibition and mortality induction in S. frugiperda larvae after thymol exposure. The detrimental effects of 2.0 and 4.0 mg/g thymol treatments on the growth and development of S. frugiperda were also examined. RNA-Seq was used to investigate the probable toxicological mechanism of thymol on S. frugiperda, resulting in the identification of 1754 and 1022 DEGs impacted by 2.0 and 4.0 mg/g thymol treatments, respectively. The DEGs associated with chitin metabolism and cuticle synthesis, hormone biosynthesis, and protein and fat digestion were subjected to additional analysis. Our findings demonstrate the efficacy of thymol in controlling S. frugiperda and lay the groundwork for understanding the molecular toxicological mechanisms of thymol on larvae.

The widespread cultivation of transgenic Bt cotton has elevated Apolygus lucorum (Meyer-Dür) to a major pest in cotton agroecosystems. Its rapidly developing resistance to insecticides poses a serious challenge to sustainable agriculture. In this study, we assessed the susceptibility of a field-collected population from Anyang, Henan Province, in relation to a laboratory-susceptible strain, to elucidate the present status and molecular basis of resistance to beta-cypermethrin. First, the toxicity of beta-cypermethrin to A. lucorum was assessed through a diet-incorporation method. Subsequently, the enzymatic activities of carboxylesterase (CarE) and glutathione S-transferase (GST) were measured, and the expression levels of CarE1 and GST1 were quantified by quantitative real-time PCR (qRT-PCR). Finally, the function of candidate genes was confirmed using RNA interference (RNAi) technology. The bioassays results indicated that the median lethal concentration (LC₅₀) for the laboratory and Anyang field strain were 343.34 mg/L and 700.45 mg/L, respectively. Following 48 h of exposure to the LC₃₀ of the susceptible strain, the mortality rate of the field population (20.00%) was significantly lower than that of the laboratory population (33.33%), suggesting an increase in resistance. The field population of A. lucorum exhibited significantly higher activities of CarE (1.61-fold) and GST (1.71-fold) compared to the laboratory strain, accompanied by 3.63- and 4.23-fold overexpression of the corresponding genes CarE1 and GST1. Spatiotemporal expression profiling revealed that CarE1 expression was highest in 4th-5th instar nymphs and adults, with predominant localization in the midgut, while GST1 expression peaked in 4th-5th instar nymphs and was abundant in the midgut and fat body. RNAi-mediated knockdown of CarE1 and GST1 significantly enhanced susceptibility to beta-cypermethrin in field populations, resulting in elevated mortality 48 h post-treatment compared to controls. In conclusion, the field population of A. lucorum has developed considerable resistance to beta-cypermethrin, strongly correlated with overexpression of CarE1 and GST1. These results deepen our understanding of metabolic resistance mechanisms and offer valuable insights for developing targeted pest control strategies.

To control maize weevils (Sitophilus zeamais), a major pest of stored grains, this study explores the use of essential oils from Eucalyptus globulus and Lantana camara as natural biopesticides. Given the risks of synthetic pesticides, these oils offer a sustainable alternative. The research first identified ten fungal pathogens associated with the weevils, including the dominant species, Fusarium solani. Preliminary results showed that both oils were then tested for their ability to kill the fungi and the weevils. Eucalyptus globulus oil proved to be a superior antifungal agent, inhibiting fungal growth by up to 93%, significantly outperforming Lantana camara oil. Both oils demonstrated potent insecticidal properties, achieving 100% weevil mortality at a 10% concentration within 24 hrs. However, Eucalyptus oil was more effective, maintaining 100% mortality even at a lower 5% concentration, unlike Lantana oil. Chemical analysis showed that Eucalyptus oil's high effectiveness may be associated with its main component, eucalyptol (52.8%). Lantana oil had a more varied composition, with caryophyllene (31%) as its primary constituent. The findings suggest that Eucalyptus globulus essential oil is a promising, two-in-one biopesticide capable of controlling both maize weevils and their associated fungal pathogens.

The repellent activities (Periplaneta americana) of lone and binary mixtures of terpenoids-geranial, trans-anethole, and trans-cinnamaldehyde-against adult American cockroaches were evaluated in this study. The respective efficacies of these mixtures were compared with that of 12% (w/w) DEET. Safety bioassays for all formulations on non-target species, namely, earthworms (Eudrilus eugeniae) and guppy fish (Poecilia reticulata), were conducted to identify natural compounds with repellent efficacy equal to or surpassing that of DEET while ensuring ecological safety for non-target organisms such as fish and earthworms. All mixtures (RC₅₀ of 0.3 to 1.6 µL/cm³) were more effective than all lone terpenoids (RC₅₀ of 6.2 to 9.1 µL/cm³) and DEET (RC₅₀ of 3.0 µL/cm³), demonstrating strong synergy, with an increased repellent value (IV) of 79 to 96%. The strongest repellency, 98.0% at 72 h and an RC₅₀ of 0.3 µL/cm³, was achieved using geranial + trans-cinnamaldehyde (1:1). This mixture was 5.9 to 10 times more effective as a repellent than DEET. The toxicity of every lone terpenoid and terpenoid mixture to non-target species was low; hence, these mixtures can be considered safe, whereas DEET was highly toxic to non-target species (100% mortality). The terpenoid mixture geranial + trans-cinnamaldehyde showed strong repellency against P. americana.

In Qinghai Province, Evergestis extimalis is an important pest of spring rape and is primarily controlled using chemical pesticides. Sex pheromones offer an alternative method for pest management in relatively non-polluted environments. In this study, the sex of E. extimalis pupae was identified, followed by isolation and structural characterization of female pheromone components using GC-EAD and GC-MS. A field attraction assay was then performed. The results showed that female pupae possess a longitudinal crack on the upper central ventral surface of the eighth abdominal segment, which connects the seventh and ninth abdominal segments. The two sides of this crack are open and flat, without protruding semicircles. Male pupae lack this longitudinal crack on the eighth abdominal segment but display one on the central ninth ventral segment, accompanied by semicircular tubercles on each side. The primary component extracted from female sex glands was identified as E11-14Ac. In field trials, E11-14 displayed a stronger attractive effect on E. extimalis males than the other tested attractants. In conclusion, E11-14Ac was preliminarily identified as the main component of the sex pheromone of E. extimalis, providing a foundation for its control using sex pheromones.

Peanut (Arachis hypogaea L.) is a globally important oilseed and food legume, yet its productivity is persistently constrained by devastating diseases and insect pests that thrive under changing climates. This review aims to provide a comprehensive synthesis of advances in precision breeding and molecular approaches for enhancing disease and pest resistance in peanut. Traditional control measures ranging from crop rotation and cultural practices to chemical protection have delivered only partial and often unsustainable relief. The narrow genetic base of cultivated peanut and its complex allotetraploid genome further hinder the introgression of durable resistance. Recent advances in precision breeding are redefining the possibilities for resilient peanut improvement. Multi-omics platforms genomics, transcriptomics, proteomics, and metabolomics have accelerated the identification of resistance loci, effector-triggered immune components, and molecular cross-talk between pathogen, pest, and host responses. Genome editing tools such as CRISPR-Cas systems now enable the precise modification of susceptibility genes and defense regulators, overcoming barriers of conventional breeding. Integration of these molecular innovations with phenomics, machine learning, and remote sensing has transformed resistance screening from manual assessment to real-time, data-driven prediction. Such AI-assisted breeding pipelines promise enhanced selection accuracy and faster deployment of multi-stress-tolerant cultivars. This review outlines current progress, technological frontiers, and persisting gaps in leveraging precision breeding for disease and pest resistance in peanut, outlining a roadmap toward climate-resilient, sustainable production systems.

Ladybird beetle, Serangium japonicum (Coleoptera: Coccinellidae), is an important predatory natural enemy of whiteflies, and its mass rearing is crucial for biological control. This study evaluated the suitability of Corcyra cephalonica (Lepidoptera: Pyralidae) eggs as an alternative diet for adult S. japonicum by directly comparing it to the natural prey, Bemisia tabaci (Hemiptera: Aleyrodidae) nymphs. Results showed that, compared to a B. tabaci diet, feeding on C. cephalonica eggs supported normal development and significantly extended the lifespan of adult S. japonicum, without compromising offspring quality (hatching rate, development, survival, or predatory capacity). However, the moth egg diet significantly impaired reproduction, causing delayed ovarian development, reduced vitellogenesis, and altered gene expression: downregulation of methoprene-tolerant, Juvenile hormone acid O-methyltransferase, Vitellogenin, and Vitellogenin receptor, and upregulation of Juvenile hormone esterase and Copper/zinc superoxide dismutase. Practically, this work defines C. cephalonica eggs as a suboptimal but viable supplementary diet for colony maintenance, but unsuitable as a sole diet for mass-rearing reproductively robust populations. Our findings explain the physiological and molecular mechanisms underlying the "reproduction-lifespan trade-off" in S. japonicum induced by feeding on C. cephalonica eggs, providing a mechanistic basis for its rational application in the mass production of natural enemies.

The polyphagous pest Oxycetonia jucunda Faldermann can cause substantial damage to a range of economically important crops, with the adult beetles feeding directly on floral tissues and young leaves. RT-qPCR is widely used to analyze gene expression, for which the selection of stable reference genes is essential for enabling an accurate normalization of expression. However, no systematic evaluations of suitable reference genes for RT-qPCR analysis using different tissues of O. jucunda have been conducted. To assess their applicability as reliable normalization controls, we used five computational methods to examine the stability of seven potential reference genes (GAPDH, EF1α, RPS3, RPS18, RPL18, RPS31, and UBC5A) across six adult tissues, with three biological replicates per tissue. The findings revealed RPS3 and RPS31 to be the most stably expressed. This pair of reference genes was further validated by normalizing the expression of the odorant-binding protein 3 (OBP3) target gene. Our findings will provide important foundational data for the accurate analysis of functional gene expression in O. jucunda.

Species delimitation in Charipinae hyperparasitoids (Hymenoptera: Figitidae) is notoriously difficult due to their minute size and limited morphological variability. Traditional diagnostic characters sometimes show intraspecific variation, raising concerns about their reliability. Here, we applied an integrative taxonomic framework to evaluate species boundaries among six species of Alloxysta Förster and four species of Phaenoglyphis Förster. We combined a morphological dataset of 53 characters with data from three molecular markers (COI, ITS2, and 16S rRNA) and reconstructed phylogenies under maximum-likelihood criteria. Phylogenies consistently recovered morphologically defined taxa as well-supported clades, confirming the overall reliability of traditional characters (pronotal and propodeal carinae, radial cell shape, and flagellomere proportions). On the other hand, molecular evidence refined certain species limits and highlighted cases of potential cryptic variation. Our results demonstrate that morphology still provides a strong baseline for Charipinae taxonomy, but integration with molecular data yields more robust and stable classifications. This study underscores the value of multi-locus approaches for resolving taxonomic ambiguities and provides a framework for future ecological and evolutionary research on these hyperparasitoid wasps.

To systematically investigate how the olfactory system of Bombus terrestris adapts to its social division of labor and reproductive strategies, this study integrated the micromorphology of antennal sensilla and the expression profiles of olfactory receptor (OR) genes from the heads of its three castes (workers, drones, and queens) for a multi-level analysis. Scanning electron microscopy (SEM) revealed that drones possess significantly longer chaetic sensilla (Sch), sensilla trichodea (Str A/B), and sensilla basiconica (Sba A), as well as larger-diameter sensilla coeloconica (Sco) compared to workers and queens, indicating structural and functional specialization for sensitive detection of single key signals (e.g., queen pheromones). In contrast, workers and queens exhibited a more complete composition of sensilla types and a higher sensilla distribution density, suggesting the construction of a perceptual system capable of processing multiple chemical signals simultaneously. RNA-seq combined with qRT-PCR confirmed the significant upregulation of seven OR genes (e.g., BterOR3, BterOR4) in drones, while workers showed upregulation of BterOR3/5/7 accompanied by enrichment of P450 detoxification pathways. Phylogenetic analysis suggested that BterOR5 serves as a conserved co-receptor, and some OR genes may originate from recent duplication events. In summary, distinct differences were observed in the morphological structure and molecular expression of the olfactory system among B. terrestris castes. Drones exhibited structural and gene expression features consistent with specialization in queen pheromone detection, while workers and queens demonstrated sensilla diversity and olfactory receptor expression patterns indicative of a broader response capacity to diverse chemical signals. These findings support the view that the olfactory system has undergone multi-level adaptive evolution driven by social division of labor and reproductive roles.