Ecology Colloquium Series - Female lizards with male-typical ornamentation have survival-enhancing strategies to offset reproductive costs
Braulio de Almeida Assis (Penn State)
The role of male ornamental traits is generally well understood within the context of sexual selection. However, females of some species display conspicuous ornamentation, the function of which is unclear. Some female fence lizards, Sceloporus undulatus, possess blue badges that are similar to, but less dramatic, than those displayed by males during courtship and dominance contests. Females bearing these badges face reproductive costs, including lower reproductive output and desirability as mates. These reproductive costs are difficult to reconcile with the maintenance of this trait and its high prevalence in some populations. To investigate the adaptive significance of this female trait, we compared performance and behavior of ornamented and unornamented female fence lizards and their offspring. Ornamented females achieved faster sprinting speeds, performed fewer agonistic displays, and had offspring that were more likely to flee from attacks by predatory invasive fire ants. These results suggest that ornamented females may have competitive advantages that may offset the reproductive costs associated with this trait. Future research will examine the mechanisms driving ornamentation, such as testosterone, and the environmental conditions that may maintain intrasexual variation in the expression of this female ornament in wild populations (e.g., resource availability and operational sex ratio).