Meeting Abstract

61.4  Wednesday, Jan. 6  Bigger is better: The effect of female ornamentation on male mate choice in the striped plateau lizard, Sceloporus virgatus BALBAG, B.S.; WEISS, S.L.*; Univ. of Puget Sound; Univ. of Puget Sound sweiss@pugetsound.edu

When females vary in reproductive quality, they may be selected to honestly signal that quality and males may be selected to express mate choice based on this variation. In the striped plateau lizard, females with larger and more saturated orange throat patches are of higher phenotypic quality, and males more closely associate with females painted to express deeper orange ornaments. More recently, it has been found that only ornament size, and not ornament color, can predict female allocation of antioxidants to egg yolk and offspring quality. Thus, we hypothesized that males should be more responsive to variation in ornament size than to variation in ornament color. We examined male response to natural variation in female ornamentation by housing males in large outdoor tents with two females and measuring their spatial relationships as well as male courtship intensity toward each of the two females. Female ornamentation was quantified in terms of size, brightness, chroma and hue. As predicted, we found that males prefer to associate with females with larger ornaments and that aspects of ornament color (i.e., brightness, chroma and hue) had no effect on male association patterns. Courtship behavior was low during our trials and was unrelated to any aspect of female color. These data suggest that males are attending to the aspect of female ornamentation that best predicts a female’s reproductive value and support the hypothesis that this ornament is sexually selected.