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Black soldier fly (BSF), Hermetia illucens (Diptera: Stratiomyidae), is a prominent insect for the bioconversion of various organic wastes. As a saprotrophic insect, the BSF inhabits microbe‐rich environments. However, the influences of the intestinal microorganisms on BSF growth and development are not very clear. In this study, the dynamics of the intestinal bacterial community of BSF larvae (BSFL) were analyzed using pyrosequencing. Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria were the most prevalent bacterial phyla in the intestines of all larval instars. The dynamic changes in bacterial community compositions among different larval instars were striking at the genus level. Klebsiella, Clostridium, Providencia, and Dysgonomonas were the relatively most abundant bacteria in the 1st‐ to 4th‐instar BSFL, respectively. Dysgonomonas and Providencia also dominated the 5th‐ and 6th‐instar larvae, at ratios of 31.1% and 47.2%, respectively. In total, 148 bacterial strains affiliated with 20 genera were isolated on different media under aerobic and anaerobic conditions. Among them, 6 bacteria, BSF1–BSF6, were selected for further study. The inoculation of the 6 isolates independently into germ‐free BSFL feeding on an artificial diet showed that all the bacteria, except BSF4, significantly promoted BSF growth and development compared with the germ‐free control. Citrobacter, Dysgonomonas, Klebsiella, Ochrobactrum, and Providencia promoted BSF development significantly by increasing the weight gains of larvae and pupae, as well as increasing the prepupae and eclosion rates. In addition, Citrobacter, Klebsiella and Providencia shortened the BSF life cycle significantly. The results illustrate the promotive effects of intestinal bacteria on BSF growth and development. [ABSTRACT FROM AUTHOR]

Sex determination has been studied in the model lepidopteran species Bombyx mori, but it remains poorly understood in lepidopteran pests. In the present study, we identified and characterized the Masculinizer (Masc) gene in a Noctuidae pest species, Agrotis ipsilon. Sequence analysis revealed that AiMasc encodes a protein of 658 amino acids that has two CCCH‐type zinc finger domains and two conserved cysteine residues (Cys‐277 and Cys‐280). We assessed the masculinizing activity of AiMasc in BmN cells and found that AiMasc induced expression of the male‐specific doublesex isoform. Disruption of Masc via clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated protein 9 (Cas9) in A. ipsilon caused abnormalities in abdominal segments and external genitalia, resulting in male‐specific sterility. These results suggest that Masc participates in the process of sex determination in A. ipsilon. Successful identification of sex‐determination gene in a pest species may enable the development of novel genetic approaches for pest control. [ABSTRACT FROM AUTHOR]