Seasonal variation in daily patterns of social contacts in the European badger Meles meles.

Matthew J Silk,Mike Boots,Lucy C Steward,David J Hodgson,Darren P Croft,Robbie A Mcdonald,Nicola Weber,Richard J Delahay

doi:10.1002/ece3.3402

Abstract

Social interactions among hosts influence the persistence and spread of infectious pathogens. Daily and seasonal variation in the frequency and type of social interactions will play an important role in disease epidemiology and, alongside other factors, may have an influence on wider disease dynamics by causing seasonal forcing of infection, especially if the seasonal variation experienced by a population is considerable. We explored temporal variation in within‐group contacts in a high‐density population of European badgers Meles meles naturally infected with Mycobacterium bovis (the causative agent of bovine tuberculosis). Summer contacts were more likely and of longer duration during the daytime, while the frequency and duration of winter contacts did not differ between day and night. In spring and autumn, within‐group contacts peaked at dawn and dusk, corresponding with when they were of shortest duration with reduced potential for aerosol transmission of pathogens. Summer and winter could be critical for transmission of M. bovis in badgers, due to the high frequency and duration of contacts during resting periods, and we discuss the links between this result and empirical disease data. This study reveals clear seasonality in daily patterns of contact frequency and duration in species living in stable social groups, suggesting that changes in social contacts could drive seasonal forcing of infection in wildlife populations even when the number of individuals interacting remains similar.

Highlights

The social behavior of animals can vary across space and time in a predictable manner (Sueur et al, 2011; Silk, Croft, Tregenza, & Bearhop, 2014)
The latter is of particular interest as seasonal forcing of infection can play an important role in infectious disease dynamics (Altizer et al, 2006; Grassly & Fraser, 2006)
The proximity-logger data collected during the present study suggests that previously established reductions in activity during winter have a substantial influence on daily patterns of social dynamics

Summary

| INTRODUCTION

The social behavior of animals can vary across space and time in a predictable manner (Sueur et al, 2011; Silk, Croft, Tregenza, & Bearhop, 2014). For many species, there may be considerable seasonal variation in the drivers of social and spatial behavior that result in substantial differences in how they interact with conspecifics (Couzin, 2006; Sueur et al, 2011; Silk et al, 2014) This seasonal variation in the nature of social interactions could have important implications for dynamic processes occurring within these populations, such as disease transmission (Altizer et al, 2006; White, Forester, & Craft, 2017). | 9008 during winter (Gallagher & Clifton-Hadley, 2000; Buzdugan et al, 2017), and concurrent peaks in contact frequency and duration occurred during this period would be consistent with a potential role for seasonal changes in social behavior in contributing to this pattern

| MATERIALS AND METHODS

Findings

| DISCUSSION

| CONCLUSIONS