Thermal Biology Of Cold-Climate Distributed Heilongjiang Grass Lizard, Takydromus Amurensis

Thermal biology traits reflect thermal adaptations to an environment and can be used to infer responses to climate warming in animal species. Within a widespread genus or species, assessing the latitudinal or attitudinal gradient of thermal physiological traits is essential to reveal thermal adaptations and determine future vulnerability to climate warming geographically. We determined the thermal biology traits of a cold-climate distributed lizard, Takydromus amurensis, and integrated published thermal biology traits within the genus Takydromus to reveal a preliminary geographical pattern in thermal adaptation. The mean selected body temperature (cloaca temperature; T-sel), critical thermal maximum (CTmax), critical thermal minimum (CTmin), and optimal temperature for locomotion (i.e., sprint speed; T-opt) of T. amurensis were 32.6, 45.1, 3.1, and 33.4 degrees C, respectively. The resting metabolic rates of T. amurensis were positively related to temperature from 18 degrees C to 38 degrees C. We compared the traits of tropical T. sexlineatus, subtropical T. septentrionalis, and T. wolteri with T. amurensis and found that the CTmax and thermal tolerance range (the difference between CTmax and CTmin; TTR) increased toward high latitudes, whereas CTmin increased toward low latitudes in these four Takydromus lizards. According to this preliminary pattern, we speculate the species at medium and low latitudes would be more vulnerable to extreme heat events caused by ongoing climate warming. We highlight the importance of integrating thermal biology traits along geographical clues, and its potential contribution to evaluate the vulnerabilities of species in the context of climate warming.