Composition and diversity of the gut microbiota across different life stages of American cockroach (Periplaneta americana)

Periplaneta americana, one of the most widely distributed insects all over the world, can survive and reproduce in harsh environment which may be closely related to the critical roles of intestinal microorganisms in its multiple physiological functions. However, the composition and structure of gut microbiota throughout different life stages and its effects on the strong resilient and environmental adaptability of P. americana remain unclear. In this study, the gut microbiota across life stages including ootheca (embryos), nymph and adult of P. americana were investigated by 16S rRNA high-throughput sequencing. Multivariate statistical analysis showed the richness and diversity of bacterial communities were significantly different among ootheca, nymph and adult stage of P. americana. Taxonomic analysis showed Blattabacterium was the dominant genus in bacterial community of ootheca while the nutrient absorption-related genera including Christensenellaceae and Ruminococcaceae showed high relative abundance in nymph samples. Moreover, functional prediction analysis showed the metabolic categories in ootheca might have more influence on the basic life activities of the host than improved production and viability, while it was more associated to the society activities, reproduction and development of host in nymph and adult. It was suggested that the gut microbiota in each life stage might meet the requirements for environmental adaptability and survival of P. americana via transforming the composition and structure with specific metabolic capabilities. Overall, these results provided a novel sight to better understand the strong vitality and adaptability throughout life stages of P. americana.