POPULATION FREQUENCIES OF ALTERNATIVE MALE PHENOTYPES IN TREE LIZARDS- GEOGRAPHIC-VARIATION AND COMMON-GARDEN REARING STUDIES

Tree lizards (Urosaurus ornatus) vary in throat fan (dewlap) color. Ea rlier, we described five dewlap types (Orange, Orange-Blue, Yellow, Ye llow-Blue, and Blue), and reported that only males had blue in the dew lap and that presence or absence of a discrete blue patch was correlat ed with male alternative reproductive phenotypes in a central Arizona population. Here, with a modified scheme characterizing two dewlap ele ments, background color (orange, yellow, blue) and blue patch occurren ce, we assessed: (1) sexual, annual, and geographic variation in the f requencies of dewlap elements; (2) simple habitat correlates; and (3) the effects of laboratory rearing regime on dewlap type. Within a popu lation, frequencies of males and females expressing orange or yellow b ackgrounds did not differ, suggesting that control of background is si milar in the sexes. Within several populations, frequencies of the dew lap elements did not differ across years (and probably generations), i ndicating that phenotype frequencies are relatively stable. Among five populations frequencies of background colors varied, as did frequenci es of male types (blue patch present or absent). Dewlap frequencies di d not correlate with habitat (boulders or mesquite trees), although fe w populations were sampled. In male and female offspring reared from e ggs to sexual maturity in a common-garden laboratory study, background color frequencies in both sexes and blue patch frequencies in males d iffered among offspring from different populations. Offspring frequenc ies matched respective parental population frequencies. Results sugges t that among-population variation in frequencies of the two dewlap ele ments are mediated by differences in genetics, in maternal effects, or both. Thus, differences in male behavior functionally linked to the b lue patch also may be controlled by genetic or maternal effects.