Fisher’s model of evolution of female preferences
The evolutionary mechanism of the emergence of secondary sexual traits – sexual selection – is relatively simple. This is true both for traits occurring on the basis of direct competition between the members of one sex (most frequently between males) and also for traits occurring on the basis of selection performed by the members of the opposite sex (most frequently females). However, an important question remains: what is the mechanism in females that fixes the tendency to prefer a certain type of male? This is especially true for those species where the striking sexual trait entails a reduction in the viability of the males and the actual process of selection of a male constitutes, at the very least, a loss of time for the females.
At the present time, there are a number of theories that explain the emergence of female preferences. The oldest theory is based on Fisher’s model of co-evolution of male traits and female preferences; however, models of sensory drive, intraspecies recognition and models included in the group of hypotheses of good genes are also popular. It is very probable that all the considered mechanisms are valid to different degrees in various species.