The Function and Mechanisms of Female Ornamentation in a Lekking Bird

The study of male ornamentation has been fundamental to advancing the understanding of sexual selection, yet we are only now beginning to examine elaborate ornamentation of females. Although female ornamentation was once thought to be non-adaptive, recent studies have provided evidence demonstrating that female ornamentation functions in both intrasexual competition and male mate choice; however, few studies have examined the role of female ornamentation in lekking species. I investigated the function and mechanisms of female ornamentation in Indian peafowl (Pavo cristatus), a lekking species in which females exhibit an elaborate ornament (iridescent green neck plumage). I quantified the brightness, chroma, and hue of neck plumage from 24 captive peahens. I tested whether female ornamentation correlates with dominance order within the female social hierarchy. I also tested whether female dominance affects courtship behavior. Finally, I tested whether the steroid hormones, estradiol and corticosterone, are predictive of variation in female ornamentation and dominance. I found that more dominant females have brighter ornaments, but there was no evidence of a relationship between dominance and either chroma or hue. Additionally, dominant females copulated more, and prevented subordinate females from interacting with displaying males. Our data did not reveal a significant relationship for estradiol or corticosterone with ornamentation or social status. This study provides insight into the evolution and function of conspicuous female traits by suggesting a role for female ornamentation in intrasexual competition in a lekking species