Cloacal Bacterial Diversity Increases with Multiple Mates: Evidence of Sexual Transmission in Female Common Lizards

Joël White,Sandrine Meylan,Manuel Massot,Murielle Richard

doi:10.1371/journal.pone.0022339

Abstract

Sexually transmitted diseases have often been suggested as a potential cost of multiple mating and as playing a major role in the evolution of mating systems. Yet there is little empirical data relating mating strategies to sexually transmitted microorganisms in wild populations. We investigated whether mating behaviour influences the diversity and composition of cloacal assemblages by comparing bacterial communities in the cloaca of monandrous and polyandrous female common lizards Zootoca vivipara sampled after the mating period. We found that polyandrous females harboured more diverse communities and differed more in community composition than did monandrous females. Furthermore, cloacal diversity and variability were found to decrease with age in polyandrous females. Our results suggest that the higher bacterial diversity found in polyandrous females is due to the sexual transmission of bacteria by multiple mates. The impact of mating behaviour on the cloacal microbiota may have fitness consequences for females and may comprise a selective pressure shaping the evolution of mating systems.

Highlights

Multiple mating by females has been the focus of numerous theoretical and empirical studies for many years [1,2,3,4]
We investigated the relationship between bacterial diversity in the cloaca of female lizards and several characteristics of these females
We found that cloacal bacterial diversity was not significantly related to body size (F1,37 = 1.60, p = 0.21), body condition (F1,37 = 0.25, p = 0.62), date of capture (F1,34 = 1.45, p = 0.24) or age (F1,34 = 3.31, p = 0.08)

Summary

Introduction

Multiple mating by females has been the focus of numerous theoretical and empirical studies for many years [1,2,3,4]. The potential benefits of polyandry for females may be direct, such as nuptial gifts or paternal care, or indirect, arising from an increase in genetic quality or diversity of the offspring [2]. Among the many suggested costs of polyandry, which include predation, energy loss, and harmful paternity assurance tactics [5], sexual transmission of pathogens is predominantly cited and has the potential for substantially reducing the benefits of multiple mating. We investigate whether mating behaviour influences the diversity and composition of cloacal assemblages by examining bacterial communities in the cloaca of female common lizards Zootoca vivipara sampled after the mating period. Two alternative female mating strategies, i.e. monandry and polyandry, coexist in this species [11]

Methods

Results

Conclusion