The Herpetological Journal

pp. 41-47
Authors: López-Alcaide, Saúl; Nakamura, Miguel; Macip-Ríos, Rodrigo & Martínez-Meyer, Enrique

Abstract: The physiological performance of reptiles is subject to specific body temperature ranges, which are frequently similar between closely-related species even when they inhabit sites with different thermal conditions. Pregnant females should be particularly efficient for thermoregulation because healthy embryos develop at a narrow temperature range, a potential problem in the context of current global warming. To test the idea that pregnant lizards adjust their thermoregulatory behaviour to rising temperatures, we set up an experiment with 40 pregnant Sceloporus adleri and measured daily activity and basking time at different treatments (22, 24, 26 and 28°C) for six consecutive days. Basking time significantly decreased with increasing temperature. Lizards were more active in the earliest two time periods of the day (0800–1030 and 1030–1300 hours) when compared to later hours (1530–1800) for all treatments, although the trend was less pronounced at 24 and 26°C. Unexpectedly, the probability of activity for lizards increased at 28°C. All lizards maintained a body temperature without significant differences across treatments. These results suggest that pregnant S. adleri females are able to adjust their behavioural thermoregulation to different thermal environments in a short period of time to maintain an adequate body temperature for key physiological processes such as development and growth of their offspring.

Keywords: THERMAL TREATMENTS, LABORATORY, REPTILES, CLIMATE CHANGE, ECTOTHERMS