Thermal ecology of Podarcis siculus (Rafinesque-Schmalz, 1810) in Menorca (Balearic Islands, Spain)

Abstract

We studied the thermal ecology of an introduced population of the Italian wall lizard, Podarcis siculus , in Menorca (Balearic Islands, Spain). We measured field body temperatures of adult lizards, as well as air and substrate temperatures at their capture places, during spring and summer. We assessed the relations between body and air temperatures, and between body and substrate temperatures, for both seasons. We studied the preferred temperature range of P. siculus in a laboratory thermal gradient. In addition, we recorded the operative temperatures of the habitat of the Italian wall lizard during summer. Then, we calculated the three indexes of behavioural thermoregulation for summer: thermal quality of the habitat, accuracy of thermoregulation, and effectiveness of thermoregulation. As expected, our results show that Italian wall lizards achieved significantly higher body temperatures during summer than during spring. Body temperatures were not significantly related to air temperatures in spring, but the correlation was significant in summer. In addition, body temperatures were not significantly related to substrate temperatures for any season. The preferred temperature range of the species was similar for males and females: 28.40-31.57 °C. Introduced Italian wall lizards of Menorca are effective thermoregulators, with an effectiveness of 0.82 during summer.