Response of conspecifics to reproductive color of female striped plateau lizards, Sceloporus virgatus

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Journal of Negative Results




Several hypotheses have been posed to explain the evolution and current function of bright reproductive color found among females in over 30 species of iguanian lizards. I use the orange reproductive color of female striped plateau lizards (Sceloporus virgatus) to address two of the lesser examined hypotheses: the female signal and sex recognition hypotheses. The female signal hypothesis suggests that female reproductive color functions as a communication signal to conspecific females and predicts that females with more developed color will dominate over females with less developed color. I addressed this hypothesis by examining competition for basking sites and food resources among groups of females painted to express dark orange, pale orange, or no orange reproductive color. I found no consistent pattern to suggest that color affects these interactions: dark orange females had a slight and non-significant advantage in obtaining preferred basking sites, pale orange females were significantly more likely to obtain the first available prey item, yet there was no effect of female color on total number of prey eaten or on feeding sequence. The sex recognition hypothesis suggests that female color functions to improve gender identification. Resident males interacted with male intruders painted to express either male-typical color or female reproductive color in a sequential stimulus design. Intruder color had no significant effect on behavior of the resident. I suggest that other cues, including chemosensory signals, are more important than female reproductive color in close-range sex recognition among S. virgatus.