SOCIAL, ENVIRONMENTAL AND GENETIC-FACTORS IN THE ONTOGENY OF PHENOTYPIC DIFFERENTIATION IN A LIZARD WITH ALTERNATIVE MALE REPRODUCTIVE STRATEGIES

Adult male tree lizards, Urosaurus ornatus, practise alternative (terr itorial or sneaker/satellite) reproductive strategies that are correla ted with differences in throat color and body size. In this study we r aised tree lizards from hatching in the laboratory to examine the ques tion of whether the phenotypic expression of secondary sex coloration and body size can be facultatively influenced by social or abiotic env ironmental factors. We compared males reared in the laboratory under d ifferent social and environmental conditions to males in the field and found no effect of different conditions on phenotypic differentiation (Figs. 2-4). Thus, phenotypic differences between morphs probably res ult largely from nonfacultative expression of different genotypes. Thi s suggests that alternative male morphs practise a mixed evolutionary stable strategy (ESS) rather than one morph making the best of a bad s ituation. However, in the context of ESS theory it is difficult to exp lain our further result that the nonterritorial morph in this species grows faster and reaches a larger adult body size than the territorial morph (Fig. 5).