Summary: Widemo & Sæther (1999)

Individuals differ in (most often) predictable ways. However, many studies investigating mate choice and mating preferences have often ignored individual variation in mating preferences, blaming this variation on errors in mate assessment, limited availability of mates or even poor observational or experimental methods. Widemo & Sæther (1999) suggest that an understanding of individual variation in mating preferences is necessary to make predictions about evolutionary change and is crucial for advancing understanding of the processes of mate choice and sexual selection. They suggest that mate choice behaviour will evolve when access to mates, or the resources they provide, are limited by the reproductive success (females) or the number of available mates (males). Furthermore, the outcomes of mate choice depend on individual mating preferences and the extent of their expression and these preferences are determined by preference functions and the degree of choosiness of individuals. Widemo & Saether (1999) regarded preference functions as being determined by ‘innate predispositions’ or flexible reference templates, or a combination of both, and suggest that individual differences in preference functions could result from phenotypic differences in sensory apparatus. Preference functions can indicate the potential for selection on a preferred trait. Choosiness is a trait that is dependent on the physiological condition of the individual and environmental and social factors. These constraints can affect the expression of preference functions. The shape of the preference function and the mate sampling tactic of an individual interact because mate-sampling tactics rely on threshold criteria for acceptance or rejection of mates. Widemo & Sæther (1999) note that to understand variation in mating preferences, there needs to be an awareness of the cues used and their relative importance.