Lock-and-key structural isolation between sibling Drosophila species

摘要: Drosophila santomea Lachaise & Harry, which is endemic to the African island of Sao Tome, and its sibling D. yakuba Burla comprise a new model system speciation. They are morphologically distinguishable only by slight differences in male genitalia body coloration. As previously undescribed difference, aedeagus bears pair stout spines (the ventral branches basal processes (VB)), instead paired humps found D. santomea. Here, we show that this difference works as lock-and-key isolating mechanism between siblings. During conspecific copulation, females receive pocket-shaped structures, protected hardened plates, genitalia. The D. santomea, lack such pockets, wounded VB when mated with males. This genital mismatching resulted leakage ejaculate, making 80% matings infertile causing prolonged struggle separate pairs glued together ejaculate.