Mate Choice

In many species one sex, usually the female is choosy selecting a mate from individuals of the opposite sex. Often the sex competing for mates, usually the male, is more colorful and showier such as male peacocks with their bright plumage than the plainer females.

Females in these species tend to have a preference for showier males in part because bright coloration can indicate good health increasing the chance that she will have healthy offspring with her chosen mate.

Because these males are more likely to reproduce their elaborate traits are passed down to future generations increasing the phenotype in the population over time. Although being colorful can raise the risk of predation, this cost is often outweighed by the benefit of increased reproductive success.

Besides appearance females often base their mate choice on male behavior such as the complexity of a male bird's song. Males of some species exhibit complex courtship behaviors such as the male bowerbird that builds a bower, a structure decorated with brightly colored objects to attract a female.

Behaviors such as these may indicate good health or the ability of the male to provide resources. For instance, a well defended territory which would give their offspring an advantage making these males more attractive as mates.