Developmental shifts in symbiotic bacterial composition and abundance in Spodoptera frugiperda (Lepidoptera: Noctidae)

Abstract

The fall armyworm (Spodoptera frugiperda) is a significant invasive pest that poses serious threats to global agriculture and food security. Microorganisms are essential for the growth and development of insects, yet the diversity and dynamics of hemolymph microbes across different developmental stages of S. frugiperda remain poorly understood. Our study reveals how the microbiome of S. frugiperda changes throughout its life cycle, with Proteobacteria and Firmicutes being the predominant bacterial phyla. Notably, the larval stage displayed a markedly different community composition compared to other stages. Fifth-instar larvae showed higher bacterial diversity than the pupal and adult stages. Among the dominant phyla, Pseudomonadota constituted 73.34%, while Bacillota accounted for 26.66%. The Enterobacteriaceae family was most prevalent, representing 33.34%. Genera such as Klebsiella, Acinetobacter, Mammaliicoccus, and Enterococcus were prominent across all developmental stages. Specifically, Klebsiella pneumoniae and Mammaliicoccus sciuri demonstrated a 50% trans-stage transmission rate from larva to pupa and from pupa to adult.