The Gut Bacterial Community of Chlaenius pallipes (Coleoptera: Carabidae) Associates with Their Habitat and Morphology

SIMPLE SUMMARY: This study aimed to determine i the gut microbiome could be used as an indicator of an organism’s health or the health of the population using the Chlaenius pallipes (Carabid beetle) as a model organism from the terraced paddy fields and the large-sized paddy fields. The composition of the gut bacterial community associated with habitat types. Gut bacterial community of C. pallipes differed in diversity, similarity, and composition between the habitat conditions. Additionally, food resource quality derived from the stable nitrogen isotope ratio was significantly correlated with richness of the gut bacterial community. ABSTRACT: We investigated whether the gut bacterial community of Chlaenius pallipes could represent the health conditions of individuals or populations based on where these beetles inhabit. Considering the ecological traits of the species, the gut bacterial communities of carabid populations inhabiting stable or unstable habitats were compared. Food resource quality (δ(15)N) and morphological shape, especially body and wing size, may be significant factors that directly or indirectly affect the gut bacterial community of carabid beetles. Firmicutes (51.7%) and Proteobacteria (36.3%) were the predominant phyla in the gut bacterial community of C. pallipes. A significant difference in the gut bacterial community structure was observed between organisms inhabiting unstable and stable habitats in this study. Wing size, as estimated by centroid size, was correlated with differences in the gut bacterial community composition of the species. Even if a factor is not strong enough to determine the survival of carabid beetles, the composition of the gut bacterial community can change. We found that although each individual has a large variation in the gut bacterial community composition, the gut bacterial community can be used to evaluate the condition of each habitat through consistent investigation. Habitat assessment based on changes in the number of carabid beetle species and their composition requires relatively long-term research; however, the gut bacterial community of carabid beetles can help identify short-term environmental changes.