In some species, the appearance of the male or his courtship displays influences a female's decision to mate with him as much or more than material considerations. It is theorized that females take these cues as indications of virility and what the male is able to offer in return for copulations. The information the female gains from hearing potential mates call allows her to select the male that will offer the most in return for copulations. Hear the mating call of the water frog, Rana lessona. Symmetry also can play a role in female selection of mates.
Females tend to prefer symmetrical males over asymmetrical ones.
Thus body asymmetry is associated with poor health or bad genes by females, forming the basis for their preference for symmetrical mates. Film actor Mel Gibson is a good example of facial symmetry and corresponding attractiveness. Selection Hypotheses Three alternative theories purport to explain the evolution of extreme sexual ornamentation and courtship displays by males. States that male courtship and appearance inform females of a potential sex partner's health or parasite load. Females could then use this information to mate with males less likely to pass on parasites or microbial pathogens.