Dynamic changes and functional analysis of gut bacteria in Plutella xylostella under different physiological conditions

Abstract BACKGROUND Insect gut bacterial communities dynamically respond to host physiology and mediate key functions, yet a holistic view of how Plutella xylostella (a devastating cruciferous pest) gut bacteria shift across developmental stages, sexes, and mating statuses remains unclear. This study applied DNA/RNA‐based 16S rRNA sequencing to capture high‐resolution dynamics of its gut microbiota and decode functional correlations. RESULTS Phylum‐level structure of P. xylostella stayed stable across both sequencing methods (Proteobacteria and Firmicutes as dominants). The top 50 high‐abundance bacterial genera annotated by both methods are also consistent, while RNA‐based 16S rRNA sequencing reveals that a greater count of high‐abundance bacteria exhibited vibrant, physiological state‐driven shifts: Eggs thrived with Streptococcus and Enhydrobacter . Larvae boasted the highest diversity (fueled by active feeding, with Ruminococcus , Prevotella may aid cellulose digestion in fed 1st‐instars and Massilia , Comamonas may boost breakdown of hard‐to‐digest food in 4th‐instars). Pupae dropped to the lowest diversity (a ‘reset’ stage, may rely on Enterobacter for energy metabolism). Non‐feeding adults had peaking Bifidobacterium and Sphingomonas (may support immune regulation). Feeding adults saw Klebsiella flourish. Sex dimorphism was striking: Males had consistent Delftia enrichment (may enhance pathogen resistance) across stages; females showed stage‐specific biases. Mating triggered marked shifts: the abundances of Lactobacillus and Faecalibacterium accumulated in mated females, potentially related to reproduction. CONCLUSION P. xylostella gut bacteria form a dynamically adaptive community, with taxa may flexibly tune to developmental, sexual, and mating demands, which is of great significance for understanding the association between the gut microbiota and their host. © 2025 Society of Chemical Industry.