Disentangling physiological and physical explanations for body size-dependent thermal tolerance

Area of Science:

• Ecology
• Physiology
• Climate Change Biology

Background:

• Climate change effects are often body size dependent.
• Size-dependent thermal tolerance (SDTT) is a key factor, where heat and cold tolerance vary with body size.
• SDTT can stem from physiological differences or physical factors influencing body temperature dynamics.

Purpose of the Study:

• To outline the mechanisms of physical SDTT and contrast them with physiological SDTT.
• To explain how physical SDTT influences thermal tolerance experiments and organismal responses to thermal variation.
• To provide a framework for distinguishing between physical and physiological SDTT and its implications for thermal ecology.

Main Methods:

• Conceptual outlining of physical SDTT mechanisms.
• Comparison of physical and physiological SDTT predictions.
• Presentation of an experimental framework to disentangle physical and physiological SDTT, using Anolis lizards as a case study.

Main Results:

• Physical SDTT arises from differences in body temperature dynamics related to size, distinct from physiological SDTT.
• Physical SDTT can confound thermal tolerance experiments.
• An experimental framework was proposed and tested using Anolis lizard data to differentiate between physical and physiological SDTT.

Conclusions:

• Differentiating physical and physiological SDTT is crucial for accurate interpretation of thermal tolerance experiments.
• Understanding physical SDTT is vital for predicting organismal responses to climate change and anthropogenic warming.
• This distinction advances fundamental knowledge in thermal ecology and adaptation.