# Anthropogenic Factors and Social Organisation Drive Picobirnavirus Communities in Wild Rhesus Macaques

## TL;DR

Human impact and social behavior strongly shape picobirnavirus communities in wild rhesus macaques in Bangladesh.

## Contribution

This study identifies anthropogenic factors and social organization as key drivers of picobirnavirus community structure in wild primates.

## Key findings

- Human and livestock densities were the strongest predictors of picobirnavirus community composition.
- Host social organization influenced viral communities at the group and site levels.
- Anthropogenic factors had opposing effects on different picobirnavirus taxa.

## Abstract

Biologists are increasingly interested in the ecological and evolutionary factors that influence microbial communities. Yet compared to bacterial communities, our understanding of viral community ecology remains limited. Here, we investigated the factors influencing viral community composition and structure among wild rhesus macaques (
Macaca mulatta
) in human‐modified environments in Bangladesh, focusing on assemblages of picobirnaviruses (PbVs) as a model system. We found that anthropogenic factors—particularly human and livestock densities—were the strongest predictors of viral community composition. Host social organisation played a secondary role, shaping viral communities at the group and site levels. Virus–virus associations influenced co‐occurrence patterns primarily within individual hosts, but their effect became less evident at broader scales. In contrast, individual host traits (age, sex and physiological stress) and viral phylogenetic relationships had minimal effects on viral co‐occurrence. Notably, anthropogenic factors had opposing effects on different PbV taxa: While some viruses were more prevalent in areas with higher human and livestock densities, others were less common, possibly due to their association with wildlife or natural environments. This suggests that macaques may acquire certain PbVs from anthropogenic sources while experiencing reduced exposure to others in human‐modified landscapes. Together, these findings reveal the dominant role of environmental and social factors in shaping viral communities and highlight the hierarchical nature of virus community assembly—with different ecological processes operating at individual, group and site scales.

We assessed the relative importance of host‐related, environmental and virus‐specific factors in influencing viral communities among wildlife hosts. Among wild rhesus macaques, we found that picobirnaviral communities were most strongly influenced by macaques' exposure to human impact, followed by their sociality and group living, and finally by virus–virus associations within hosts. Our study addresses critical gaps in our understanding of viral community ecology, adding to a growing perception of viruses as being integral components of host ecology and ecosystems.