Female ornamentation influences male courtship investment in a lizard

Female signals of reproductive status often comprise both distinctive color patches and behaviors but their relative influence on male courtship investment is unclear. We examined the role of female-specific coloration in signaling reproductive condition and quality to males in the Lake Eyre dragon lizard, Ctenophorus maculosus. Females of this species develop intense orange ventral coloration when sexually receptive, which fades to white only after laying. To separate the effect of color and behavior, we manipulated the presence of female orange ventral coloration within different periods of the reproductive cycle in which females display qualitatively different behaviors. In a separate manipulation, we tested whether the presence of an ultraviolet (UV) component, size and intensity of female orange patches influenced male courtship investment. Males tended to chase, bite, and copulate more with orange than white females, irrespective of reproductive state. However, males copulated much more frequently with receptive females than non-receptive or gravid females, consistent with females' behavioral acceptance of copulations during this stage. Males courted females with small orange patches the most, and had an overall preference for intense color patches (as opposed to pale orange patches), regardless of the presence of UV. Our results suggest that female orange coloration signals reproductive condition, specifically receptivity, and that small, intensely orange patches signal that females are more likely to be receptive. Female ornamentation therefore encodes information used by males to make decisions regarding courtship investment.