A holocenic and dynamic hybrid zone between two cactophilic Drosophila species in a coastal lowland plain of the Brazilian Atlantic Forest

Hybridization and introgression are processes that contribute to shaping biological diversity. The factors promoting the formation of these processes are multiples but poorly explored in a biogeographical and ecological context. In the southeast coastal plain of the Brazilian Atlantic Forest, a hybrid zone was described between two closely related cactophilic species, Drosophila antonietae and D. serido. Here, we revisited and analyzed specimens from this hybrid zone to evaluate its temporal and spatial dynamic. We examined allopatric and sympatric populations of the flies using independent sources of data such as mitochondrial and nuclear sequences, microsatellite loci, morphometrics of wings and male genitalia, and climatic niche models. We also verified the emergence of the flies from necrotic tissues of collected cacti to verify the role of host association for the population dynamics. Our results support the existence of a hybrid zone due to secondary contact and limited to the loc...