Adaptive seasonal shifts in the thermal preferences of the lizard Iberolacerta galani (Squamata, Lacertidae)

The León rock lizard, Iberolacerta galani, lives in isolated mountains of Spain. We studied the seasonal changes in the thermal biology of I. galani between spring and summer. We calculated precision, accuracy and effectiveness of thermoregulation and the habitat thermal quality for spring, and compared with the values of summer. In addition, we studied how the shift in the thermal preferences of lizards would contribute to achieve a higher effectiveness of thermoregulation. Thermal preferences of León rock lizards are among the lowest in lacertids, and are also very narrow, maintaining the narrowness among seasons. As for summer (27.90-29.70 °C, mean value =28.76 °C), the thermal preferences of I. galani are also low in spring (29.60-31.10 °C, mean value =30.38 °C), supporting the idea that this species is adapted to cold environments. The habitat thermal quality is lower in spring (10.99 °C) than in summer (9.36 °C), while the effectiveness of thermoregulation is higher in spring (0.92) than in summer (0.80). We found that the seasonal shift in thermal preferences contributes significantly to enhance the effectiveness of thermoregulation in both seasons, more in spring (0.45 °C) than in summer (0.16 °C). Because I. galani inhabits isolated mountains, where the activity period is reduced from April to October, we hypothesize that the observed adaptation of the thermal preferences, which enhance thermoregulation to a larger extent in spring, may evolved to maximize performance during the reproductive season.