Molecular evolution of the cacophony IVS6 region in sandflies.

A number of insects produce acoustic signals during courtship. Genes involved in the control of the courtship song are particularly interesting from an evolutionary viewpoint because interspecific variation in this signal is potentially important as a reproductive isolation mechanism and, as a consequence, in the speciation process. The cacophony gene was identified by a mutation affecting the "lovesong" in Drosophila melanogaster. Phlebotomine sandflies (Diptera: Psychodidae) also produce acoustic stimuli during courtship and therefore cacophony can be used as an interesting molecular marker in evolutionary studies in these important disease vectors. In this paper we have studied the molecular evolution of the IVS6 region of cacophony in sandflies. We compared the level of divergence in the exon sequences encoding this conserved domain in Drosophila and Phlebotomines. We also analysed the high level of variation in an intron that is present in sandflies but that was lost in Drosophila during evolution. The available cacophony sequences were also used for a phylogenetic analysis of some species of the Neotropical genus Lutzomyia.