Speciation is a rare phenomenon. Yet in Mayotte scientists (among them Jean David, IGGIPOP) described a population of D. yacuba drosophila feeding on the fruit of the Morinda tree which is toxic to flies on the african continent. This could provides the geographic isolation and the ecological specialization that are necessary to speciation.
The article was published in PNAS. It was also the subject of a short article on the INEE site.