&lt;i&gt;Wolbachia&lt;/i&gt; induces sexual isolation in &lt;i&gt;Drosophila melanogaster&lt;/i&gt; and &lt;i&gt;Drosophila simulans&lt;/i&gt;

Ialah Gazla,María C Carracedo

doi:10.4236/ojgen.2011.12005

Abstract

Wolbachia are a group of intracellular bacteria, ma-ternally transmitted from infected females to their offspring, which affect a wide range of arthropods. Their presence is associated with Cytoplasmic Incompatibility (CI) in crosses between infected males and uninfected females and between populations carrying different strains of Wolbachia. The negative influence of Wolbachia a infection on progeny fitness in incompatible crosses can be considered a first step in the appearance of reproductive isolation between infected and uninfected individuals. In this work, we examined the possibility of assortative mating in response to Wolbachia infection, a response that evolved as an incipient mechanism of sexual isolation in the species D. melanogaster and D. simulans. We found that the females of each species could detect the presence of the bacterium in the other sex and chose to mate with males who had the same state of infection, whereas the males randomly attempted to mate with both infected and uninfected females. Thus, Wolbachia may act as an additive factor influencing sexual isolation in Drosophila populations and may play a role in speciation events.

Highlights

Species are groups of individuals that mate between themselves and share genes but are reproductively isolated from other populations and species
Wolbachia are a group of intracellular bacteria, maternally transmitted from infected females to their offspring, which affect a wide range of arthropods
We examined the possibility of assortative mating in response to Wolbachia infection, a response that evolved as an incipient mechanism of sexual isolation in the species D. melanogaster and D. simulans

Summary

Introduction

Species are groups of individuals that mate between themselves and share genes but are reproductively isolated from other populations and species. Speciation depends on the establishment of reproductive isolation between populations of the same species. Two mechanisms can establish reproductive isolation: postmating, which prevents gene flow between populations by progeny sterility and/or inviability, and premating, which prevents mating between individuals [1,2]. Sexual isolation is a premating mechanism that occurs when individuals meet but do not mate. Sexual isolation is total between remote species but partial between related species, at least under laboratory conditions. Sexual isolation can be viewed as an incompatibility or disharmony between the sexual behaviour of two populations or species, a situation that favours homospecific over heterospecific matings (assortative mating)

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