Illegitimate exploitation of sexual signalling systems and the origin of species

Abstract

The sexual signals passed between conspecific males and females in the context of mate attraction and stimulation also are available for exploitation by predators and parasites. These «illegitimate» receivers have profoundly influenced the evolution of sexual signalling systems within populations, as briefly reviewed in this paper. I then extend this concept to groups of conspecific populations exposed to different communities of exploiters. I hypothesize that selection in the form of arms-races among «exploited» and «exploiter» species may cause divergence of sexual signalling systems in the former (in both traits and preferences). This divergence may be sufficient to generate sexual isolation among populations, permitting further population differentiation and, perhaps, the origin of new species. Results of recent research on the ethology and ecology of male sexual signals and female preferences in the guppy Poecilia reticulata are used to test this hypothesis.