Intraspecific variations in coloration may represent a compromise between selection for intraspecific communication and selection for thermoregulation and predator avoidance. Iberian wall lizards, Podarcis hispanica, exhibit substantial levels of intraspecific variation that cannot be necessarily attributed to genetic differences. We compared variations in coloration and habitat use of three phenotypically distinct populations of P. hispanica in Central Spain. Results suggested that differences in coloration may be related to habitat characteristics and climatic conditions. Thus, lizards from populations with colder temperatures were darker and larger, which may favor thermoregulation. Lizards that lived in habitats with more vegetation and darker granite rocks showed a dark brown to black dorsal coloration. In contrast, lizards from habitats with gypsum and light sandy soil without vegetation or large rocks had a brighter yellow to green dorsal coloration. These differences may increase crypsis to predators in each habitat. There were also differences in the characteristics and relative importance of sexual visual signals (i.e., ventrolateral coloration and number of lateral blue spots) and chemical signals (i.e., number of femoral pores) that might increase efficiency of communication in each environment. Natural selection for traits that allow a better thermoregulation, predator avoidance, and communication might lead to population divergence. 1. Introduction Intraspecific variation in coloration is an intriguing phenomenon found in a widespread number of animal taxa, particularly vertebrates [1–3]. Animal coloration represents a compromise between selection for signaling functions in intraspecific communication (i.e., sexual signals) and selection for thermoregulation and defense against visually oriented predators [2, 4–10]. According to this, differences in coloration between species and populations or between sexes and age classes are the result of subtle differences in the balance between natural and sexual selection [4, 5, 9, 11]. Variation in coloration on a large geographical scale is essentially found in response to variations in climate, habitat, and predators [3, 12–14]. Correlational selection will promote that coloration will become associated genetically and developmentally with other traits . In reptiles, color variations have long been studied as examples of adaptive evolution [14, 16, 17]. On the one hand, coloration impacts thermoregulation in ectotherms because darker reptiles are able to warm faster and maintain higher body
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