Abstracts (first author)
Effect of Wolbachia infection on the courtship song of Drosophila paulistorum and D. equinoxialis
Understanding the processes that can lead to speciation are one of the main goals in evolutionary biology. It has been proposed that coevolution between parasite and its host can potentially drive speciation. A good model for studies of infectious speciation is the neotropical fly Drosophila paulistorum spp.. This species complex is currently under incipient speciation in nature and consists of six semispecies that are in an obligatory mutualistic relationship with bacteria of the Wolbachia genus. Previous studies have determined that infection with Wolbachia is associated with hybrid inviability and male sterility. Interesting enough, Wolbachia not only cause postzygotic isolation in the D. paulistorum complex but also prezygotic isolation through an influence on assortative mating between the different semispecies. These data suggest that the infection is modulating some courtship signal that allows self-recognition among the semispecies. Among the different male signals involved in mate recognition in Drosophila species, courtship song is one of the most studied and is well known to affect isolation between close related species. Here we recorded the courtship song of males from three D. paulistorum semispecies and also of its sibling species D. equinoxialis comparing wild type infected lines with lines treated with antibiotics where the bacteria titer were reduced. Our result shows a significant variation in the interpulse interval (IPI) associated with the infection with Wolbachia in all groups. We discuss whether the changes are likely to influence sexually selection or are more likely to reflect changes in male condition following curing of the Wolbachia infection.