Insect Science最新文献

Bemisia tabaci is a complex of cryptic agro-economically important pest species characterized by diverse clades, substantial genetic diversity along with strong phylogeographic associations. However, a comprehensive phylogenomic analysis across the entire complex has been lacking, we thus conducted phylogenomic analyses and explored biogeographic patterns using 680 single-copy nuclear genes (SCNs) obtained from whole-genome sequencing data of 58 globally sourced B. tabaci specimens. We constructed both concatenation and coalescent trees using 680 SCNs, which produced highly supported bootstrap values and nearly identical topologies for all major clades. When comparing these concatenation trees with those constructed using mitochondrial cytochrome oxidase I (mtCOI) and mitochondrial genome, we found conflicting phylogenetic relationships, with the later trees recovering fewer major clades. In a separate comparison between concatenation and coalescent trees, particularly those generated using IQ-TREE, they were found to delineate population relationships more effectively than RaxML. In contrast, coalescent phylogenies were proficient in elucidating geographical dispersal patterns and the reorganization of biological species. Furthermore, we provided a strict consensus tree that clearly defines relationships within most clades, laying a solid foundation for future research on the evolution and taxonomy of B. tabaci. Ancestral range estimates suggested that the ancestral region of the complex is likely situated in equatorial Africa, the Middle East, and Mediterranean regions. Subsequently, the expansion occurred into part of the Palearctic and further into the Nearctic, Neotropical, Indomalayan, and Australasian regions. These findings challenge both previous classifications and origin hypotheses, offering a notably more comprehensive understanding of the global distribution, evolutionary history, diversification, and biogeography of B. tabaci.

Black soldier fly larvae (BSFL) were reared on mixtures of swine manure and circulating fluidized bed fly ash (CFA) in different ratios. The aim was to evaluate the impacts of insoluble inorganic matter on BSFL and larval frass. The growth performance and nutrient composition of the BSFL were measured under different treatments. The intestinal microbiota structure, morphological characteristics, and total proteolytic activity of the gut were analyzed. The larval frass was tested for nutrients and analyzed using energy-dispersive spectroscopy and scanning electron micrographs. In particular, the surface areas of microparticles from the larval frass (diameter < 0.0074 mm) were measured using Brunauer-Emmett-Teller method. It was found that CFA addition prolonged larval development and reduced the maximum larval weights. The mean larval length, crude protein, and highest larval weight showed negative regression with an increase in the CFA ratio (P < 0.05). Morphological images indicated that physical clogging might be the main influencing factor on larval growth. Moreover, the microbial diversity and complexity in the larval gut increased with CFA addition, but CFA addition had little effect on the composition of dominant phyla or genera (P > 0.05). Finally, the nutrient composition revealed that the frass met the organic fertilizer standard when the CFA addition ratio was less than 7.5%. The optimal addition ratio was 5%, at which the larvae had a more stable and healthier gut environment, but there was less of an effect on larval growth and nutrient composition. Moreover, particles from 5% CFA mixture had the highest surface area.

The escalating demand for sustainable and eco-friendly pest management strategies has raised interest in harnessing the pathogenic potential of microorganisms. Serratia marcescens, a Gram-negative bacterium, has emerged as a potential biological control agent for sustainable pest management. This review critically examines the history, biology, identification, and pathogenicity of S. marcescens strain with their potential application in pest management. The diverse mechanisms employed by the strain to exert control over pests, including the production of metabolites and the induction of systemic resistance in plants, are examined. The review also summarizes the ecological significance and global distribution of S. marcescens associated with the use of S. marcescens in biological control strategies. Furthermore, the usage efficacy of S. marcescens over other conventional chemicals is discussed. A comprehensive understanding of the pathogenic potential of S. marcescens strains as biological control agents is crucial for developing effective and sustainable pest management strategies. This review consolidates current research advances on S. marcescens, and provides insights into the prospects and challenges of using S. marcescens for integrated pest management.

Arthropod melanization is a crucial defense mechanism mediated by a complex cascade of CLIP domain serine proteases (CLIPs). In this study, it was confirmed that microRNA-11903a (miR-11903a) targets Aedes-CLIPB9 (AeCLIPB9) by bioinformatics prediction and dual-luciferase reporter assays. Following intrathoracic injection of miR-11903a agomir and antagomir, Real-time quantitative polymerase chain reaction confirmed that AeCLIPB9 is negatively regulated by miR-11903a. Spatiotemporal expression analysis revealed that miR-11903a is most abundant in 4th instar larvae, followed by pupae and adults, and highly expressed in the wings, head, and midgut of female adults. Following pathogen infection, AeCLIPB9 and miR-11903a exhibited opposite expression trends, indicating their potential roles in mosquito innate immunity. To further investigate the relationship between AeCLIPB9 and miR-11903a, double-strand CLIPB9 was synthesized and RNA interference was performed. Seven-d survival assays revealed that both AeCLIPB9 and miR-11903a were crucial immune factors in fighting pathogens. Finally, longevity assays demonstrated that miR-11903a influenced mosquito lifespan.

Cimex species are ectoparasites that exclusively feed on warm-blooded animals such as birds and mammals. Three cimicid species are known to be persistent pests for humans, including the tropical bed bug Cimex hemipterus, common bed bug Cimex lectularius, and Eastern bat bug Leptocimex boueti. To date, genomic information is restricted to the common bed bug C. lectularius, which limits understanding their biology and to provide controls of bed bug infestations. Here, a chromosomal-level genome assembly of C. hemipterus (495 Mb [megabase pairs]) contained on 16 pseudochromosomes (scaffold N50 = 34 Mb), together with 9 messenger RNA and small RNA transcriptomes were obtained. In comparison between hemipteran genomes, we found that the tetraspanin superfamily was expanded in the Cimex ancestor. This study provides the first genome assembly for the tropical bed bug C. hemipterus, and offers an unprecedented opportunity to address questions relating to bed bug infestations, as well as genomic evolution to hemipterans more widely.

The silk gland of the silkworm Bombyx mori serves as a valuable model for investigating the morphological structure and physiological functions of organs. Previous studies have demonstrated the notable regulatory role of let-7 microRNA in the silk gland, but its specific molecular mechanism remains to be elucidated across different segments of this organ. In this study, we further investigated the functional mechanism of let-7 in the middle silk gland (MSG). The MSG of a let-7 knockout strain was analyzed using a combined proteomic and metabolomic technique, revealing the enrichment of differential proteins and metabolites in the DNA synthesis and energy metabolism pathways. BmCentrin was identified as a novel target gene of let-7 in the MSG, and its downregulation inhibited the proliferation of BmN4-SID1 cells, which is exactly opposite to the role of let-7 in these cells. CRISPR/Cas9 genome editing and transgenic technologies were employed to manipulate BmCentrin in the MSG. Knockout of BmCentrin led to severe MSG atrophy, whereas the overexpression of BmCentrin resulted in beaded MSG. Further measurements of these knockout or overexpression strains revealed significant changes in the expression levels of sericin protein genes, the weight of the cocoon and the mechanical properties of the silk. Investigating the biological role of BmCentrin in the silk gland offers valuable insights for elucidating the molecular mechanisms by which let-7 controls silk gland development and silk protein synthesis in the silkworm.

C-type lectins (CTLs) act as pattern recognition receptors (PRRs) to initiate the innate immune response in insects. A CTL with dual carbohydrate recognition domains (CRDs) (named immulectin-4 [IML-4]) was selected from the Ostrinia furnacalis transcriptome dataset for functional studies. We cloned the full-length complementary DNA of O. furnacalis IML-4 (OfIML-4). It encodes a 328-residue protein with a Glu-Pro-Asn (EPN) and Gln-Pro-Asp (QPD) motifs in 2 CRDs, respectively. OfIML-4 messenger RNA levels increased significantly upon the bacterial and fungal infection. Recombinant OfIML-4 (rIML-4) and its individual CRDs (rCRD1 and rCRD2) exhibited the binding ability to various microorganisms including Escherichia coli, Micrococcus luteus, Pichia pastoris, and Beauveria bassiana, and the cell wall components including lipopolysaccharide from E. coli, peptidoglycan from M. luteus or Bacillus subtilis, and curdlan from Alcaligenes faecalis. The binding further induced the agglutination of E. coli, M. luteus, and B. bassiana in the presence of calcium, the phagocytosis of Staphylococcus aureus by the hemocytes, in vitro encapsulation and melanization of nickel-nitrilotriacetic acid beads, and a significant increase in phenoloxidase activity of plasma. In addition, rIML-4 significantly enhanced the phagocytosis, nodulation, and resistance of O. furnacalis to B. bassiana. Taken together, our results suggest that OfIML-4 potentially works as a PRR to recognize the invading microorganisms, and functions in the innate immune response in O. furnacalis.

The vast majority of all global species have circadian rhythm cycles that allow them to adapt to natural environments. These regular rhythms are regulated by core clock genes and recent studies have also implicated roles for microRNAs in this regulation. Oviposition is an important circadian behavior in the reproductive cycle of insect vectors of diseases, and little is known about the rhythm or its regulation in mosquitoes. Aedes albopictus is a diurnal mosquito that transmits arboviruses and is the major cause of outbreaks of dengue fever in China. We analyzed the oviposition rhythm patterns of A. albopictus under different light/dark conditions and show that the mosquitoes have an oviposition peak between zeitgeber time 9 (ZT 9) and ZT 12. Furthermore, the antagomir-mediated knockdown of expression of the microRNA miR-2940-1 affected the oviposition rhythm of A. albopictus. These data support the conclusion that miR-2940-1 is involved in the regulation of oviposition rhythm in A. albopictus and provide a foundation for using oviposition rhythms as a new target for vector mosquito control.

Given the limited availability of resources in nature, sexual attractiveness may trade off with immunocompetence, as the immunocompetence handicap hypothesis (ICHH) posits. In invertebrates, a direct link between trade-offs through hormonal/molecular effectors in sexual signals and immunity has not been found so far. Here, we assessed how variation in sexual signals affected parasite infection in two sex pheromone selected lines of the moth Chloridea virescens: an attractive line with a low ratio of 16:Ald/Z11-16:Ald and an unattractive line with a high ratio. When infecting these lines with an apicomplexan parasite, we found that the attractive Low line was significantly more susceptible to the parasite infection than the unattractive High line. Since the ratio difference between these two lines is determined by a delta-11-desturase, we hypothesized that this desaturase may have a dual role, i.e., in the quality of the sexual signal as well as an involvement in immune response, comparable to testosterone in vertebrates. However, when we used CRISPR/cas9 to knockout delta-11-desturase in the attractive Low line, we found that the pheromonal phenotype did change to that of the High line, but the infection susceptibility did not. Notably, when checking the genomic location of delta-11-desaturase in the C. virescens, we found that mucin is adjacent to delta-11-desaturase. When comparing the mucin sequences in both lines, we found four nonsynonymous SNPs in the coding sequence, as well as intronic variation between the two lines. These differences suggest that genetic hitchhiking may explain the variation in susceptibility to parasitic infection.