Traditionally, investigators and theorists have supposed that mate choice is directional and fixed within a species as well as static within individuals over time. Lately, accumulating evidence shows that mate choice is often flexible, so that individuals change their behavior, depending on the social or ecological situation they experience or their condition. Recent theory proposes that animals should change their mate choice adaptively moment by moment in response to changes in environmental, internal, and social factors. Mate choice plasticity should be explored more in empirical studies as well as its implications for mate choice evolution and sexual selection.
This is an updated version of the chapter published in 2010.