Body Size and Paternity in a Teiid Lizard (Ameiva exsul)

Male and female Ameiva exsul share overlapping home ranges. As a consequence sexually receptive females may have access to several males. We studied the effect of relative male size on paternity in five experimental populations of adult male and female A. exsul that were held in naturalistic 100 m2 enclosures. Each population, which initially consisted of three males and three females, was followed for a breeding season. Behavior was tallied from data gathered by focal animal observation. Progeny were ob- tained by harvesting clutches of eggs from the sand piles in which the animals denned. DNA samples from embryonic tissue and from blood of adults were compared to determine parentage using RAPD-PCR with bands scored as dominant markers. Body size was strongly associated with male reproductive success in the enclosures: the largest male in each enclosure sired the most progeny, and overall, with enclosures as sta- tistical blocks, large males sired significantly more progeny than did medium or small males. Nevertheless, small males obtained some paternity, and so were not completely excluded from reproduction. We detected multiple paternity in one of the clutches. Contemporary views of Darwinian sexual se-