LAUSR

BACKGROUND Spodoptera frugiperda is an important invasive agricultural pest, that causes huge economic losses worldwide. Gut microorganisms play a vital role in host feeding, digestion, nutrition, immunity, growth, and insecticide resistance. Illumina high-throughput sequencing was used to study the gut microbial community dynamics across the life cycle (egg, first to sixth instar larvae, pupae, and male and female adults) of S. frugiperda fed on maize leaves. Furthermore, the gut microbial community and food intake of the fifth instar S. frugiperda larvae were studied after feeding them antibiotics. RESULTS Enterobacteriaceae and Enterococcaceae dominated the gut during growth and feeding of the larvae. The relative abundance of Enterobacteriaceae was higher in the fourth and sixth instar larvae. With the increase in larval feeding, the relative abundance of Enterococcaceae gradually increased. In addition, principal coordinate analysis and linear discriminant effect size analysis confirmed differences in the structure of gut microbiota at different developmental stages. After antibiotic treatment, the relative abundance of Firmicutes, Proteobacteria, and Fusobacteriota decreased. The relative abundance of Enterococcus and Klebsiella decreased significantly. Antibiotic treatment inhibited the gut flora of S. frugiperda, which decreased larval food intake and body weight gain, and prolonged the larval stage. CONCLUSION The composition of the gut bacterial community plays an important role in the growth, development, and feeding of S. frugiperda. The results have a certain theoretical value for the development of bio-pesticides targeting intestinal flora. This article is protected by copyright. All rights reserved.