Sympatric Speciation by Sexual Conflict

Sergey Gavrilets† and David Waxman‡

Proceedings of the National Academy of Sciences 99, 10533–10538 (2002)

†Departments of Ecology and Evolutionary Biology and Mathematics, University of Tennessee, Knoxville, TN 37996-1610 USA;
‡Centre for the Study of Evolution, School of Biological Sciences, University of Sussex, Brighton BN1 9QG, Sussex UK

It is well established that sexual conflict can drive an endless coevolutionary chase between the sexes potentially leading to genetic divergence of isolated populations and allopatric speciation. We present a simple mathematical model that shows that sexual conflict over mating rate can result in two other general regimes.First, rather than "running" away from males, females can diversify genetically into separate groups effectively "trapping" the males in the middle at a state characterized by reduced mating success. Female diversification brings coevolutionary chase to the end. Second, under certain conditions males respond to females diversification by diversifying themselves. This results in the formation of reproductively isolated clusters of genotypes which emerge sympatrically.