The Phylogenetic Distribution of a Female Preference

Robust phylogenetic information can be instrumental to the study of the evolution of female mating preferences and preferred male traits. In this paper, the evolution of a preexisting female bias favoring a sword in male swordtail fish and the evolution of the sword, a complex character, are used to demonstrate how the evolution of mating preferences and preferred traits can be examined in a phylogenetic context. Phylogenetic information suggests that a preference for a sword arose prior to the evolution of the sword in the genus Xiphophorus and that the sword was adaptive at its origin. A phylogenetic approach to the study of female preferences and male traits can also be informative when used in conjunction with mate choice theory in making predictions about evolutionary changes in an initial bias, both prior to the appearance of the male trait it favors and subsequent to the appearance of the trait. (Mate choice; female preference; preexisting biases; Priapella; swordtail; sword; Xiphophorus.) The study of the evolution of mating preferences is an area of much contention. Until relatively recently, there was dis- agreement over the importance of female mate choice. In the past 15 years, however, many studies have shown that females ex- hibit mating preferences and that these mating preferences can have an important