Gut Microbiota Provide Co-Existing Strategies for Two Species of Symmetrically Distributed Rodents in Competition for Food.

Gut microbiota provides an effective strategy for sympatric proximal species to coexist in interspecific competition. In the present study, 16S rRNA gene sequencing was used to investigate the gut microbial of the Cricetulus longicaudatus and Apodemus agrarius, which are two species distributed in the same domain, under natural ambient and varying dietary situations. Our data revealed that there were significant differences in gut microbial structure and diversity between the two species. Specifically, the C. longicaudatus demonstrated high alpha diversity and an abundance of Lactobacillus, whereas A. agrarius showed substantial enrichment of Verrucomicrobiota. Wild C. longicaudatus had a more complex co-occurrence network, with a low level of positive correlation rate; however, after being fed various diets, the network structure was simplified, and the positive correlation rate increased. On the contrary, wild A. agrarius had a simple co-occurrence network, with a high level of positive correlation rate; after exposure to different diets, the network structure became more complex, accompanied by a decrease in the positive correlation rate. Our results also revealed differences in dietary adaptation between the two species. C. longicaudatus exhibited a greater microbial adaptability under a high-fat and high-fiber diet than A. agrarius, as indicated by a significant rise in the Firmicutes/Bacteroidetes ratio. While A. agrarius demonstrated reduced adaptation to dietary changes, it had a stronger ability to adapt to a high-fat diet than to a high-fiber diet. Finally, our data revealed significant alterations in carbohydrate metabolism pathways between the two species. This study provides new insights into how the gut microbiota of symmetrically distributed rodents provides effective survival strategies for species in the face of competition.