title: Sexual differences in behavioral thermoregulation of the lizard Scelarcis perspicillata.
abstract: Temperature determines all aspects of the biology of ectotherms. Although sexual differences in thermal ecology are not the rule in lizards, some species exhibit such differences. We studied the effect of sex and reproductive condition on the thermoregulation of an introduced population of Scelarcis perspicillata during the summer in Menorca (Balearic Islands, Spain). These lizards live in the wall surfaces of a limestone quarry, where the sun is scarce because of the narrowness of the quarry walls. The population is sexually dimorphic, with larger males than females. We measured body temperature (Tb) of adult males and females in the field, and air (Ta) and substrate temperature (Ts) at the capture sites, and recorded exposure to sunlight, height of the perch, and type of substrate. We also recorded operative temperatures (Te) as a null hypothesis of thermoregulation. Finally, we studied the thermal preferences of adult males and females in a laboratory thermal gradient. Thermal preferences were similar for pregnant and non-pregnant females, and sex did not affect the thermal preferences of lizards, even after controlling for the effect of body size. However, in the field, females achieved higher Tbthan males, and occupied microhabitats with higher Taand Tsand lower perch heights than males. Furthermore, females selected perches in full sun at a higher frequency than males. As a consequence, females achieved a higher accuracy and effectiveness of thermoregulation (0.89) than males (0.84). Thus, all else being equal, females would achieve a higher performance than males. The observed results are attributable to sexual differences in behaviour, probably in relation with the reproductive season.
authors.affiliation: Department of Animal Biology, University of Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain. Electronic address: zaidaortega@usal.es.
authors.forename: Zaida
authors.initials: Z
authors.lastname: Ortega
authors.affiliation: Department of Animal Biology, University of Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain.
authors.forename: Abraham
authors.initials: A
authors.lastname: Mencía
authors.affiliation: Department of Animal Biology, University of Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain.
authors.forename: Valentín
authors.initials: V
authors.lastname: Pérez-Mellado
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D049628:Body Size; D001831:Body Temperature; D001833:Body Temperature Regulation; D017753:Ecosystem; D005260:Female; D008116:Lizards / Q000502:physiology*; D008297:Male; D012727:Sex Characteristics
keywords: Heliothermy; Lacertidae; Scelarcis perspicillata; Selection of microhabitat; Sex; Thermoregulation