MEASURING FEMALE MATING PREFERENCES

Interest in the evolution of female mating preferences has increased g reatly in recent years, and numerous hypotheses have been proposed to explain how mating preferences evolve. Despite this interest, little i s known about how selection acts on mating preferences in natural popu lations. One reason for this lack of information may be that experimen tal designs commonly used for testing female preferences make it diffi cult to quantify the preferences of individual females. Most commonly used designs share three features: they examine the preferences of pop ulations of females, they test female responses when they are presente d simultaneously with two stimuli, and they infer information on femal e preferences by observing female choices between alternative stimuli. Population-level choice tests, in which each female is tested only on ce with a set of stimuli, do not evaluate within-female variation in p reference, which is necessary to document between-female variation in I,reference. Two-stimulus designs test only for directional preference s if female responses are tested with only a single pair of stimuli. I n addition, dichotomous scoring of female responses makes detection of between-female variation in preference difficult. Simultaneous stimul us presentations can confound female preference and female sampling be haviour. An alternative method to assess female preferences is to meas ure repeatedly the preference functions of individual females using a single-stimulus design. The shape of a female's preference function in dicates how a female's mating response varies with male trait value, a nd repeated measures of individual preference functions allow measurem ent of within-and between-female variation in preferences. (C) 1998 Th e Association for the Study of Animal Behaviour.