Thermal constraints and the influence of reproduction on thermoregulation in a high-altitude gecko (Quedenfeldtia trachyblepharus)

Temperature plays a crucial role for ectotherm performance and thus for fitness. Terrestrial ectotherms, including reptiles, regulate their body temperature mainly by behavioural means. At high altitude, however, thermal constraints make precise thermoregulation costly. The cost–benefit model of lizard thermoregulation predicts that thermally challenging environments should favour the evolution of thermoconformity. Yet, several species maintain high and stable body temperatures even in cool environments. We studied the Atlas Day Gecko, Quedenfeldtia trachyblepharus, a cold‐adapted lizard endemic to the High Atlas Mountains of Morocco. We quantified thermoregulation in gravid females, non‐gravid adult females, and adult males during the active season. Geckos thermoregulated during their active season, and thermoregulated with more effectiveness early in the season than late in the season. In the laboratory, the preferred body temperature ranges of gravid females, non‐gravid females, and males were not significantly different. In the field, however, gravid females had smaller deviations from the preferred body temperature and maintained higher body temperatures than males and non‐gravid females. Our study suggests that cold‐adapted reptiles adjust their thermoregulatory behaviour in response to thermal constraints and reproductive status. Cold climates are particularly challenging for ectothermic animals because thermal conditions constrain physiological performance and activity. The Atlas Day Gecko, Q. trachyblepharus, is the only Mediterranean gecko specialized in high mountain habitats. We demonstrated that this species has high thermal preferences and that gravid females thermoregulate more precisely compared to males and non‐gravid females.