Speciation, sexual selection, and the macroevolution of cricket mating signals

Abstract

Animal mating signals can communicate both species-specific recognition information and male phenotypic quality persuasion information to females. Using a comparative framework across an entire clade, we show that mating signal traits specifically associated with conspecific signal recognition show fast initial divergence during speciation, followed by relative stasis at equilibrium, and that this effect is enhanced among species pairs with the potential for gene flow. In contrast, sexually selected persuasion mating signal evolution is not associated with initial species divergence. These results reveal mechanistically how and when rapid mating signal evolution facilitates speciation and challenge the prevailing view that traits experiencing intrapopulation sexual selection are likely to be the major traits which promote interspecific divergence. In particular, the results suggest that the mechanistic link between sexual selection and speciation is ephemeral. We expect that the distinction between recognition and persuasion traits, and the particular importance of divergence in recognition traits for speciation, should be a widespread phenomenon.