# Gut Microbiome of Two Rodent Species (Niviventer confucianus and Apodemus agrarius) from Two Regions Exhibit Different Structures and Assembly Mechanisms

## TL;DR

This study shows that the gut microbiomes of two rodent species differ between two Chinese regions due to geographic influences on their microbial communities.

## Contribution

The study reveals how geographic regions shape gut microbiome structure and assembly mechanisms in conspecific rodent hosts.

## Key findings

- Geographic region significantly influences gut microbiome alpha diversity and co-occurrence networks in rodents.
- The Anhui region's rodent gut microbiome shows 'small world' network characteristics, facilitating rapid microbial interaction.
- Dispersal limitations and heterogeneous selection dominate microbiome assembly in Anhui and Hubei regions, respectively.

## Abstract

The influence of different regions on the structure and assembly mechanisms of the animal gut microbiome has long been of interest to scientists. This study investigated the gut microbiome of Niviventer confucianus and Apodemus agrarius collected from Anhui and Hubei provinces. We aimed to characterize the bacterial co-occurrence networks and elucidate the assembly mechanisms of the gut microbiota in conspecific hosts across different geographical regions. We found that the geographic region shaped the gut microbiome of conspecific rodents by altering the alpha diversity, co-occurrence networks, and assembly processes. However, further analysis is needed to determine which factor of the two geographical regions is the main factor affecting the gut microbiota of the two rodent species.

The structure and assembly mechanism of wild animal gut microbiota represent persistent research hotspots. Among, the impact of geographic factors on the bacterial co-occurrence network characteristics and assembly mechanism of the gut microbiome remains unclear. Therefore, this study analyzed the gut microbiome of Niviventer confucianus and Apodemus agrarius from Anhui and Hubei provinces. The same alpha diversity pattern was found in the gut microbiome of species from the same region. The gut microbiome of the two rodent species in Anhui region exhibited “small world” characteristics, such as nodes with more local connections to allow interaction information (such as metabolites) to rapidly spread throughout the entire microbial community. In addition, dispersal limitations and heterogeneous selection accounted for higher proportions of the gut microbiome in the rodents from the Anhui and Hubei regions, respectively. The higher proportion of heterogeneous selection may exacerbate selection pressure in the Hubei region. Multiple regression on distance matrices analysis revealed that geographic region exerted a limited but significant influence (0 < R2 < 0.2, * p < 0.05) on the gut microbiome, surpassing the effects of host phylogeny, gender, and weight. Nevertheless, the roles of regional factors—such as environmental microbes, pollutants, and diet—remain unexamined, and their potential as key drivers of microbiota variation in these rodents warrants further investigation.