Sexual selection and speciation

The power of sexual selection to drive changes in mate recognition traits g ives it the potential to be a potent force in speciation. Much of the evide nce to support this possibility comes from comparative studies that examine differences in the number of species between clades that apparently differ in the intensity of sexual selection. We argue that more detailed studies are needed, examining extinction rates and other sources of variation in sp ecies richness. Typically, investigations of extant natural populations hav e been too indirect to convincingly conclude speciation by sexual selection . Recent empirical work, however, is beginning to take a more direct approa ch and rule out confounding variables.