Gut microbiota provide co-existing strategies for two species of symmetrically distributed rodents in competition for food

The adaptability of gut microbiota provides an effective strategy for sympatric proximal species to coexist in interspecific competition. In the present study, 16SrDNA was used to investigate the gut microbial composition, diversity, co-occurrence networks, and metabolic functions of the long-tailed dwarf hamster (Cricetulus longicaudatus) and the striped field mouse (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 rodents in the wild. Specifically, the voles demonstrated high alpha diversity and abundance of Lactobacillus, whereas the mice shown 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 adaption between the two species. C. longicaudatus exhibited a greater microbial adaptability under high-fat and high-fiber dietary conditions than A. agrarius, as indicating by a significant rise in the Firmicutes/Bacteroidetes ratio. While A. agrarius demonstrated reduced adaptation to dietary changes, and it had a stronger ability to adapt to high-fat food than to high-fiber food. These data reveled that C. longicaudatus employed microbial diversity for dietary adaptability, whereas A. agrarius relied on microbial interactions for rapid adaptation, indicating that the two species employed distinct ecological adaptation strategies. Finally, our data revealed significant alterations in carbohydrate metabolism pathways, such as sucrose-6-phosphatase, between the two species in wild, while, after varying dietary situations, there was no significant change in the functional prediction. 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 for food.