Structure of the Gut and Ovary, with Associated Microbiota Across Life Stages in the Striped Stem Borer Chilo suppressalis (Lepidoptera: Crambidae)

The striped stem borer Chilo suppressalis (Lepidoptera: Crambidae) is one of the most serious pests of water bamboo Zizania latifolia. Microbiota dynamics across the life cycle of C. suppressalis are a prerequisite for comprehending the symbiotic relationship between C. suppressalis and its microbiota. In this study, we characterized the structural features of the gut and ovary, as well as the associated microbiota of C. suppressalis. The gut is anatomically divided into the foregut, midgut and hindgut. Notable structural and ultrastructural differences were observed between adults and larvae, the details of which have not been previously documented. Microbial sequencing of gut, ovary, and egg samples revealed variations in relative sequence abundances among these tissues. At the phylum level, Proteobacteria and Firmicutes were the predominant groups. At the family level, Bacillaceae, Enterobacteriaceae, Enterococcaceae, Halomonadaceae, Moraxellaceae, and Streptococcaceae were detected in the gut, ovary, and egg, albeit with different relative sequence abundances. The larval midgut exhibited the highest bacteria diversity among all samples examined. The compositional distribution of bacterial genera varied considerably across developmental stages, diet, and gut compartment, and some genera were identified as core microbial taxa. These findings provide a descriptive account of the microbial community structure associated with different tissues and life stages of C. suppressalis. They also provided important insights into the investigation of insect–bacteria symbioses, thereby facilitating effective biocontrol of this species.