MATING STRATEGY AND REPRODUCTIVE SUCCESS IN THE TEIID LIZARD, AMEIVA-PLEI

Current selection on sexual size dimorphism was studied in a widely fo raging non-territorial lizard, Ameiva plei. Males were significantly l arger than females. Large males won intrasexual agonistic encounters a nd guarded females during their entire receptive period (1-4 days). Gu arding males spent significantly less time foraging than males who wer e alone. Only males that guarded females were observed to mate. Mating success was highly skewed with only six of 21 mature males in the stu dy site observed mating. All six males who mated were greater than or equal to 141 mm SVL (males mature at 62 mm SVL). The four largest male s obtained 84% of all observed matings and were estimated to have fert ilized 88% of the eggs. Sexual selection appears to favor large size i n males due to competition among males to guard females. Large females on Anguilla also had higher reproductive success because SVL as posit ively correlated with clutch size and number of clutches in a season. It appears that natural selection has favored different trade-offs bet ween growth and reproduction in males and females.