FEMALE CHOICE ON MALE QUANTITATIVE TRAITS IN LIZARDS - WHY IS IT SO RARE

Female choice on the basis of male traits has been described in an arr ay of taxa but has rarely been demonstrated in reptiles. In the sand l izard (Lacerta agilis), and possibly in other non-territorial reptiles , a male's contribution to a female's fitness is restricted to his gen es. In order to choose males of high genetic quality, females have to trade the fitness gain against the costs of active choice. In a Swedis h population of sand lizards, long-lived males sired offspring with hi gher embryonic survival compared to offspring sired by short-lived mal es. In spite of this female sand lizards did not mate selectively with older and/or larger males. There appeared to be no reliable cues to m ale longevity; age-specific male body size was highly variable. Furthe rmore, estimates of male nuptial coloration did not covary with ectopa rasite load and, hence, females cannot use male coloration as a cue to heritable resistance to pathogenic parasite effects. When cues to mal e genetic quality are poor, or inaccurate, and males make no parental investment, we predict that female choice will be rare. Sand lizard fe males mating with many partners lay clutches with higher hatching succ ess. Thus, females may obtain ''good genes'' for their young by multip le mating, thereby avoiding costs associated with mate choice.