Gut microbiota influences female choice and fecundity in the nuptial gift-giving species, Drosophila subobscura (Diptera: Drosophilidae)

Benjamin S Walsh,Zenobia Lewis,Chloe Heys

doi:10.14411/eje.2017.056

Abstract

Recently, there has been rapidly growing interest in the effects of the microbiota on host physiology and behaviour. Due to the nutritional value of bacteria, gut microflora may be particularly important in species that present nuptial gifts during courtship. Here, we explore whether the presence or absence of gut microbiota in males and females of the nuptial gift-giving species Drosophila subobscura (Collin, 1936) alters mating behaviour in terms of female preference, male investment, and female fecundity. We found that females that had been fed antibiotics, compared to females with intact gut bacteria, were more willing to mate with a male that had been fed normally. However female fecundity was higher when both males and females lacked gut bacteria compared to both individuals having a full complement of gut bacteria. This implies that the presence of the microbiota acts to reduce female fecundity in this species, and that male gut bacterial content influences female fecundity. Our results provide further evidence to the growing consensus that the microbiota of an individual may have important effects on both reproductive behaviour and physiology, and suggest that it may also contribute to the nutritional value of the nuptial gift in this system.

Highlights

There has been rapidly growing interest in the effects of the microbiota: the parasitic, commensal, and symbiotic microorganisms residing within and on their host
This study suggests that gut bacteria can have an important impact on both the behaviour and the physiology of Drosophila subobscura
We found that female treatment had a significant impact on their mating behaviour. Females that had their gut microbiota suppressed mated faster with males that had an intact microbiota, whereas females with an intact gut microbiota were less willing to mate with males with an intact microbiota

Summary

Introduction

There has been rapidly growing interest in the effects of the microbiota: the parasitic, commensal, and symbiotic microorganisms residing within and on their host (reviewed in Lewis & Lizé, 2015). The community of bacteria residing in the gut of the host has, in particular, received attention as it has been shown to have important effects on the fitness (e.g. Rosengaus et al, 2011), behaviour (e.g. Sharon et al, 2010), and evolution (e.g. Brucker & Bordenstein, 2013) of the host. When naturally occurring gut bacteria in D. melanogaster are removed, males transfer less sperm to related females as compared to unrelated females, which reduces the potential costs of inbreeding. This suggests the presence of a naturally occurring kin recognition ability that is suppressed by gut bacteria. It is of great importance to examine any other potential physiological and behavioural effects that commensal gut bacteria can have on its host species. One area that remains underexplored with regards to the microbiome and both mating behaviour and physiology is the potential link between microbes in the gut, and the composition of nuptial gifts

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