Sensory drive speciation and patterns of variation at selectively neutral genes

Speciation by sensory drive can occur if divergent adaptation of sensory systems causes rapid evolution of mating traits and the resulting development of assortative mating. Previous theoretical studies have shown that sensory drive can cause rapid divergent adaptive evolution from one to two phenotypes. In this study, we examined two topics: the possibility of adaptive radiation by sensory drive from one to more than two phenotypes and the relationships of patterns of variation at selectively neutral genes to levels of viability selection, habitat and mating preferences and migration. We conducted individual-based simulations assuming a sensory trait and a mating trait controlled by a small number of loci. We found that adaptive radiation is possible when the number of loci controlling the sensory trait is small; the levels of viability selection, habitat and mating preferences are intermediate; and the emigration rate is high. We also found that emigration rates as well as the levels of habitat and mating preferences are related to F _ST values at neutral loci, but F _ST proved to be insensitive to a small change in the number of loci controlling the mating trait. This suggests that an estimation of the past population history is possible without an accurate genetic model.