A specialized gut microbiota reflecting the unique diet of Kurixalus eiffingeri tadpoles

The importance of symbiotic microbial communities in shaping the traits and behaviors of organisms is widely recognized. Especially, in species that utilize specific food resources, gut microbiota tend to exhibit unique specialization. In the Eiffinger’s tree frog (Kurixalus eiffingeri), tadpole exclusively feeds on trophic unfertilized eggs. This carnivorous dietary specialization is exceptional among anuran larvae, and therefore, we predict that K. eiffingeri larvae may possess a specialized gut microbiota, compared to larva of other species. Our analysis using 16S rRNA amplicon sequencing revealed that the gut microbiota of K. eiffingeri tadpoles is markedly specialized compared to other species, showing a simplified microbial composition that corresponds to their specialized diet. Additionally, in K. eiffingeri, the gut microbiota of tadpoles closely resembled that of adults, suggesting the possibility of vertical transmission of gut microbiota from parent to offspring via trophic eggs. Furthermore, based on the bacterial composition identified through the analysis, bacteria belonging to the genera Bacteroides and Akkermansia were found to be characteristic of the gut microbiota of K. eiffingeri. The specialization of the gut microbiota in this species likely reflects its unique dietary habits.