Revisiting the History and Biogeography of Bactrocera oleae and Other Olive-Feeding Fruit Flies in Africa and Asia

<i>Bactrocera oleae</i> Rossi causes important agricultural losses in olive growing regions. Despite its economic relevance, the expansion history and biogeography of <i>B. oleae</i> and other olive-feeding fruit flies remain unclear. We used mitogenomic data of <i>Bactrocera</i> species from a broad geographic range to explore possible historical biogeographic patterns in <i>B. oleae</i> and other olive-feeding fruit flies. Our data suggest that (1) the transition from stenophagy on Oleaceae to oligophagy on <i>Olea</i> most likely occurred in Africa more than 6 million years ago (MYA), and (2) the subsequent transition to monophagy on <i>Olea europaea</i> took place in Asia or in Africa in the Early Pleistocene. Our results support equally the hypotheses that the ancestors of modern <i>B. oleae</i> underwent two waves of migration from Asia to Africa or that they zigzagged between Asia and Africa.