The Herpetological Journal

pp. 51-55
Authors: Carretero, M. A.; Roig, J. M. & Llorente, G. A.

Abstract: The intraspecific variation of preferred temperatures (Tp) was analysed in an oviparous population of Lacerta vivipara and compared with viviparous populations. Lizards collected in central Pyrenees were exposed to a thermal gradient and Tp was measured at four time intervals. Tp was strongly dependent on lizard condition (males > non-pregnant females > pregnant females = immatures) and more weakly with time of day (early morning > mid-day). Individual females increased their Tp after egg-laying. Class-by-class comparisons did not reveal substantial differences with viviparous populations as expected for the thermal rigidity hypothesis. Nevertheless, on a short time scale, Tp should be interpreted as a compromise between different selective pressures including not only thermal environment but also reproductive condition and energy allocation.

Keywords: LIZARD, BEHAVIOUR, THERMOREGULATION