The evolution of female choice when the preference and the preferred trait are linked to the same inversion system

Abstract

This study reports results of computer simulations of the evolution of female mating preferences when both the preference and the preferred character are associated with the same chromosomal inversion system. When there is strong heterosis associated with the inversion system and no direct selection acting on mating preferences, a pattern of disassortative mating with respect to the inversion is predicted to evolve. Females mating disassortatively produce highly fit heterokaryotypic offspring. However, when heterosis is weak, Fisherian sexual selection can maintain strong assortative preferences, but the inversion polymorphism is lost. Assortative preferences are only likely to be maintained in conjunction with a polymorphic inversion system if direct sexual selection is operating. The results of this study are discussed with respect to the seaweed fly, Coelopa frigida, in which the preference and preferred trait are associated with the αβ inversion system.