Natural selection can act against maladaptive hybridization between co-occurring divergent populations leading to evolution of reproductive isolation among them. A critical unanswered question about this process that provides a basis for the theory of speciation by reinforcement, is whether natural selection can cause hybridization rates to evolve to zero. Here we investigated this issue in two sibling mosquitoes species, Aedes mariae and Ae. zammitii, that show post-mating reproductive isolation (F1 males sterile) and partial pre-mating...