Ovipositor transcriptomes reveal an evolutionary conserved mechanism of oviposition substrate choice in Drosophila

Introduction: Proper selection of oviposition site is a fundamental animal behaviour that highly affects the survival of the progeny. In insects, females use different environmental cues, such as odorants or tastants, to choose the best possible site; the molecular bases of this key behaviour are complex, involving different chemoreceptors scattered through the insect body, and part of them remains still mostly unexplored. Methods: In this study, we analyzed the whole-gene expression of four Drosophila species ovipositors, including that of D. suzukii, an invasive pest which oviposits on fresh rather than fermenting fruits, and three Drosophila species which served as successive outgroups (D. subpulchrella, D. biarmipes and D. melanogaster). Results/Conclusion: We found that all species express various taste-related genes, such gustatory and ionotropic receptors, as well as odorant binding-proteins. While some genes are expressed in all the Drosophila species tested, others are species-specific. Overall, our results reveal a conserved mechanism of oviposition site choice in Drosophila, which is likely modulated in different species by the expression of species-specific receptors or binding proteins which we suggest are involved with adaptation to specific ecological niches.