2026/03/04 by Sanja Drakulić, Anne Stephan, Mark-Oliver Rödel +2 · 1 voice
Environmental Science · Agricultural and Biological Sciences · #Physiological and biochemical adaptations #Bat Biology and Ecology Studies #Amphibian and Reptile Biology
paper · doi:10.1016/j.cbpa.2026.111990
Amphibians, like other ectotherms, must balance conflicting demands for energy expenditure, physiological processes, and behaviour in response to environmental temperature variations that influence their survival and reproduction. Understanding these dynamics is crucial for assessing amphibians' resilience to climate change and identifying the stressors they face in their thermal environments. Our study investigated the influence of ambient temperature (T a ) on RMR in adult Rana temporaria and how the frogs' thermoregulatory reality in the field (field body temperature, T b ) while being active aligns with their responses to a wider range of temperatures in a thermal gradient (preferred temperature, T pref ). As anticipated for ectotherms, the RMR increased with T a , doubling with each 10 °C increment, in accordance with the Q 10 coefficient. Consequently, absolute changes in RMR increased with increasing temperature. In the thermal gradient experiment, frogs primarily selected temperatures around 25 °C. At this temperature, which is not too far from the critical maximum temperature (CT max ) of 30 °C, RMR was 0.106 mL O2 g −1 h −1 . The mismatch between actual field T b and laboratory T pref highlights the constraining influence of other environmental factors such as favourable microhabitat availability or hygric conditions. This study suggests an effective balance between energy requirements and thermoregulatory behaviour in R. temporaria , if favourable conditions are available. However, it also shows that the environmental reality of animals often deviates from unimpeded preference of active individuals and thus results from experimental procedures might not necessarily reflect the situation in the field.