Evolutionary and Ecological Drivers of Gut Microbiota in Wild Rodent Species from the Yucatán Peninsula

The host-microbiome association is considered a coevolutionary process, in which the microbiome provides important functions for host development, physiology and health. However, the ecological and evolutionary forces shaping the diversity and structure of the bacterial communities that form the microbiome are still being elucidated. We assessed the composition of gut microbiota in six rodent species from three geographic regions across the Yucatán peninsula, Mexico. We evaluated the contribution of host species identity, phylogenetic relationships, and geography to the rodents' gut microbiota, using 16S rRNA V4 sequences. We performed a comprehensive set of analytical approaches, including Hill numbers, machine learning, and phylogenetic comparative frameworks. Our results show that phylosymbiosis is one of the main mechanisms driving microbiota dissimilitude across species and specific microbiota diversity traits. Additionally, the microbial pool in each region was geographically differentiated, shaped by the rodent community ensemble, while ecological filtering rendered a microbial pool characteristic of each species. The environment also played a significant role for some species like Heteromys gaumeri, while dietary habits showed a stronger signal for Oryzomys couesi. Rodents with more specialized habits like Ototylomys phyllotis (semi-arboreal, folivorous) had higher bacterial diversity. The abundance of eight bacterial families determined key differences of the gut microbiota which, in addition to phylogeny and geography, are associated with distinct diet and metabolic functions among rodents. Distinct metabolic functions were related, among others, to toxins metabolism and digestion of complex food components. Overall findings show that both evolutionary and ecological drivers influence these rodents gut microbial structure and composition.