Insects最新文献

Chitin is a critical component of both the exoskeleton and internal structures of insects, which can protect insects from mechanical damage, dehydration and pathogen infection, and plays a significant role in the molting process. Chitin deacetylases (CDAs), key enzymes involved in chitin metabolism, are widely distributed among arthropods and microorganisms. In this study, we identified a CDA gene, TaCDA1, in the invasive insect species Tuta absoluta (Meyrick). Sequence analysis demonstrated a high degree of similarity to CDAs in other insects, revealing the presence of three conserved domains. Quantitative analysis showed that the TaCDA1 gene exhibited peak expression during the pupal stage, particularly within the epidermis. The suppression of TaCDA1 expression through RNA interference in T. absoluta pupae significantly impacted the expression of genes associated with chitin metabolism, increasing mortality and developmental abnormalities during the pupa-adult transition and reducing the pupal weight. Furthermore, soaking gene-specific dsRNA resulted in elevated mortality rates during the larva-pupa transition, causing the inability to form new cuticles or undergo ecdysis, as confirmed by subsequent histological observations. The oral administration of dsTaCDA1 + sucrose solution did not significantly impact NtCDA1 expression or the mortality rate compared to the dsGFP + sucrose solution control in the non-target insect Nesidiocoris tenuis. This study demonstrated that TaCDA1 is a potential and safe target for pest control of T. absoluta.

Insecticides are widely used to boost crop yields, but their effects on non-target insects like Vespa magnifica are still poorly understood. Despite its ecological and economic significance, Vespa magnifica has been largely neglected in risk assessments. This study employed physiological, biochemical, and transcriptomic analyses to investigate the impact of sublethal concentrations of thiamethoxam, avermectin, chlorfenapyr, and β-cypermethrin on Vespa magnifica. Although larval survival rates remained unchanged, both pupation and fledge rates were significantly reduced. Enzymatic assays indicated an upregulation of superoxide dismutase and catalase activity alongside a suppression of peroxidase under insecticide stress. Transcriptomic analysis revealed increased adenosine triphosphate-related processes and mitochondrial electron transport activity, suggesting elevated energy expenditure to counter insecticide exposure, potentially impairing essential functions like flight, hunting, and immune response. The enrichment of pathways such as glycolysis, hypoxia-inducible factor signaling, and cholinergic synaptic metabolism under insecticide stress highlights the complexity of the molecular response with notable effects on learning, memory, and detoxification processes. These findings underscore the broader ecological risks of insecticide exposure to non-target insects and highlight the need for further research into the long-term effects of newer insecticides along with the development of strategies to safeguard beneficial insect populations.

Effective postharvest management is crucial for the U.S. peanut industry, given the humid-subtropical climate that promotes insect pests, Aspergillus mold, and aflatoxin contamination in peanut-producing states. This study surveyed five conventional metal warehouses (CMWs) and thirteen flat storage facilities (FSFs) in northeastern, southeastern, and southwestern Georgia, USA, from December 2022 to July 2023. Peanuts were sampled monthly to assess the temporal abundance and diversity of storage insect pests, damage variables, and aflatoxin levels in farmers' stock peanuts. A monoclonal antibody-based affinity chromatographic assay determined the total aflatoxin levels in samples. The most common insect species, accounting for ~85.73 of the total captured, included Cryptolestes ferrugineus, Tribolium castaneum, Ahasverus advena, Plodia interpunctella, Cadra cautella, Ephestia elutella, Liposcelis spp., and Lachesilla pedicularia. Insect populations peaked in June and July, with similar diversity trends across CMWs and FSFs. Insect-damaged kernels, weight loss, discolored kernels, loose-shelled kernels, moisture content, and aflatoxin levels ranged from 3.02 to 11.45%, 1.11 to 3.60%, 2.11 to 11.20%, 1.56 to 4.91%, 6.89 to 8.85%, and 0.43 to 27.59 ppb, respectively. The high prevalence of insect pests, their damage capabilities, and the aflatoxin levels of infested peanuts highlight the need for an improved IPM strategy in warehouses to ensure safe and sustainable peanut storage in the USA.

In the Białowieża Forest, Norway spruce is the preferred host tree species for wood ants, both in coniferous and mixed stands; thus, spruce mortality as a consequence of a continuous spruce bark beetle outbreak in the Białowieża Forest since 2012 could have severe consequences for wood ant colonies, as well as their vitality and distribution. The main aim of this study was to assess whether the bark beetle outbreak had any effects on wood ant nest density and abundance and whether we could find any factors affecting the dead spruce distribution around ant nests. A re-inventory of active and abandoned wood ant nests in our study area was conducted from April to July 2022, using the same procedure as the previous inventory performed in 2016. The wood ant nest density was 0.11 per ha and remained practically the same relative to that determined in 2016. Our results indicate that, despite the importance of spruce for wood ants, in situations when only part of the spruce trees die, natural forest disturbances such as bark beetle outbreaks can actually have positive effects because more light can reach the forest floor, thereby promoting the establishment of new nests.

Citrus rust mites (Phyllocoptruta oleivora Ashmead) are a major pest in citrus orchards, significantly affecting fruit quality and yield. Effective management of these mites is crucial for maintaining the economic viability of citrus production. This study investigated the ecological distribution of citrus rust mites and their natural predator, A. largoensis, in a mandarin orchard in Zengcheng District, Guangzhou City, of China. This research focused on population densities across different orchard sections and assessed the impact of mite infestations on the biochemical composition of mandarins, including vitamin C, soluble solids, acidity, and mineral content. Results showed that citrus rust mite populations were highest in the southern and western sections of the orchard. Infested fruits had reduced vitamin C and soluble solids but increased acidity and calcium levels. A. largoensis exhibited a strong functional (Type II) and numerical response, with higher predation rates and reproductive output for moderate prey densities. The findings emphasize the importance of targeted pest management strategies in citrus rust mite hotspots and highlight A. largoensis as a promising biological control agent. Future research should optimize its use in integrated pest management programs by focusing on areas of the orchard with high mite densities.

This study considered using insect families as bioindicators to establish the health status of an ecosystem of lentic bodies. The water quality in urban lentic bodies in the Metropolitan Region, Chile, was evaluated from aquatic insect family assemblages and physicochemical variables for conserving aquatic life. Evaluations were carried out in parallel at four sampling stations of three water bodies (Batuco Wetland, Carén Lagoon, and Chada Reservoir) in a 2-3-year series, spring (2015, 2017, and 2018) and fall (2016 and 2018), with three replicates. Families were randomly sampled and aquatic insects were identified; abundance and richness differences were compared with non-parametric tests. Physicochemical variables were measured using portable multiparametric and laboratory chemical analyses to determine the water quality. A Canonical Correspondence Analysis was applied for insect families and the physical-chemical variable. In order to categorize the health of these water bodies based on aquatic insect composition and abundance, the Family Biotic Index (FBI), British Biological Monitoring Work Party (BMWP), and Stream Invertebrate Grade Number-Average Level (SIGNAL), adapted for Chile by Figueroa et al. (2007), were calculated. The eudominant insect families were Corixidae and Chironomidae in Batuco, Chironomidae and Corixidae in Carén, and Corixidae in Chada. Baetidae was dominant in Carén and Chada. The water bodies were classified in descending order of water quality by Chilean physicochemical standards: Chada > Carén > Batuco. The TSS (total suspended solids), phosphorus, and electrical conductivity were strongly positively correlated and negatively associated with dissolved oxygen. The TSS level was the most significant influential factor. The BMWP value and the SIGNAL differed from the FBI, but the first was more restrictive, contributing to the conservation of these ecosystems. Based on the nitrogen and phosphorus levels in the water bodies, all of them were eutrophic. Given the ecosystem diversity and complexity, studies should delve deeper into wetlands to establish methods that contribute to determining water quality, using insect families as bioindicators and physicochemical variables.

Adults and immatures of Aedes epactius were collected in July and December 2022 at sites of high elevation in the states of Chihuahua (2300 masl) and Zacatecas (2182 and 2595 masl), Mexico, respectively. Mosquitoes were identified morphologically and sequenced for a DNA barcode of the cytochrome c oxidase I (COX1). This is the first distributional record of Ae. epactius in Zacatecas and provides evidence of the highest altitude in the Americas, including Mexico. The geographical distribution of Ae. epactius in Mexico was reviewed, and the COX1 analysis, using phylogenetic Bayesian analysis to confirm species identification, was performed.

The hindwing geometry, aspect ratio, and numerical modeling of susceptible, Bt-Corn- and rotation-resistant western corn rootworm (WCR) wings was investigated. All variants had similar hindwing geometries and aspect ratio (AR: 6-7). These AR values correspond to wings suited to lower altitude flights of a shorter distance. These AR values are characteristic of wings that can carry heavier loads and are capable of precision flying. Numerical modeling using the finite element method (FEM) showed that the Bt-Corn-resistant and rotation-resistant WCR hindwings could potentially resist higher wind speeds with minimal deformations compared to conspecific susceptible WCR. Understanding the physiology and dispersal of resistant WCR enables a better understanding of how these variants spread their alleles across large scale agricultural landscapes. This may have important implications for integrated resistant management strategies for WCR.

In this study, honeybee viruses were identified in naturally infected honeybee colonies (Apis mellifera carnica). From nine selected samples of clinically affected and ten samples of healthy honeybee colonies, different strains of honeybee viruses were first detected using quantitative real-time RT-PCR methods. Twenty-two nucleotide sequences of the complete genomes of honeybee viruses were identified using the Illumina Next-Generation Sequencing (NGS) method: acute bee paralysis virus (ABPV) (n = 4), black queen cell virus (BQCV) (n = 3), chronic bee paralysis virus (CBPV) (n = 2), deformed wing virus (DWV) (n = 5), Lake Sinai virus (LSV) (n = 4), sacbrood bee virus (SBV) (n = 1), Apis rhabdovirus-1 (ARV-1) (n = 1), bee macula-like virus (BeeMLV) (n = 1) and Hubei partiti-like virus 34 (HPLV34) (n = 1). The nucleotide sequences of ABPV, BQCV, DWV and SBV are the first complete genomes of these viruses identified in Slovenia and they represent an important contribution to our understanding of the genetic diversity of honeybee viruses. ARV-1, BeeMLV and HPLV34 were detected and sequenced for the first time in Slovenia.

Dacnusini is a species-rich tribe in the subfamily Alysiinae, with most species exclusively serving as parasitoids of leaf-mining Diptera (Agromyzidae). The number of genera discovered in China remains limited, which is apparently insufficient considering the global diversity of species and genera within this tribe, particularly given the vast and ecologically diverse landscapes of China. In the present study, three new record genera, Victorovita Tobias, Coloneura Foerster, and Laotris Nixon, were documented for the first time in China. In addition, the species delimitation approach and haplotype network analyses based on the COI sequences, combined with morphological evidence, were employed to delimit species. The findings indicated three new species: Laotris glabella sp. nov., Laotris aethidentata sp. nov., and Victorovita aequalis sp. nov. Additionally, K2P divergences showed no overlap between intra- and interspecific genetic distances in the Laotris and Victorovita species. Detailed descriptions for new species and keys to the species of Laotris and Victorovita are provided in this paper, along with the documentation of two new species records for China: Victorovita caudata (Szépligeti, 1901) and Coloneura stylata Foerster, 1863.