Drosophila Sexual Attractiveness in Older Males Is Mediated by Their Microbiota.

Chloe Heys,Tom A R Price,Anne Lizé,Zenobia Lewis

doi:10.3390/microorganisms8020168

Abstract

Age is well known to be a basis for female preference of males. However, the mechanisms underlying age-based choices are not well understood, with several competing theories and little consensus. The idea that the microbiota can affect host mate choice is gaining traction, and in this study we examine whether the male microbiota influences female preference for older individuals in the fruit fly Drosophila pseudoobscura. We find that an intact microbiota is a key component of attractiveness in older males. However, we found no evidence that this decrease in older male attractiveness was simply due to impaired microbiota generally reducing male quality. Instead, we suggest that the microbiota underlies an honest signal used by females to assess male age, and that impaired microbiota disrupt this signal. This suggests that age-based preferences may break down in environments where the microbiota is impaired, for example when individuals are exposed to naturally occurring antibiotics, extreme temperatures, or in animals reared in laboratories on antibiotic supplemented diet.

Highlights

Choosing the right mate can have a major impact on a female’s fitness [1]
Female preference for old males has been documented in a number of species of Drosophila [13,14,15], with preference for both young males [16] and males of an intermediate age [4] shown in a variety of other insects
Copulation duration was directly affected by male age (Figure 2), with older males copulating for significantly longer than young males

Summary

Introduction

Choosing the right mate can have a major impact on a female’s fitness [1]. Where males only provide sperm to females, females often choose mates in order to gain genetic benefits for their offspring [2,3]. Older males may be genetically superior to young males as they are proven survivors, potentially indicating that they possess fewer maladaptive alleles [7,8]. Another suggestion is that signals of quality are more reliable in older males [9]. A preference for older males could be a true preference, with females benefiting from mating with older males, and using some honest signal of male age to make their choice. Older males may be better at harassing or manipulating females into mating, despite this not benefitting the female

Methods

Results

Conclusion