Cutaneous Evaporative Water Loss in Lizards Changes Immediately with Temperature

Area of Science:

• Physiology
• Ecology
• Herpetology

Background:

• Cutaneous evaporative water loss (CEWL) is crucial for water balance in terrestrial vertebrates.
• CEWL is known to vary with evolutionary and acclimatory changes in temperature and humidity.
• The rapid, short-term lability of CEWL has not been previously investigated.

Purpose of the Study:

• To investigate the acute effects of body temperature changes on CEWL in western fence lizards (Sceloporus occidentalis).
• To determine if CEWL exhibits plasticity on short timescales (seconds to minutes).

Main Methods:

• Western fence lizards were subjected to rapid heating or cooling over 15 minutes.
• Cutaneous evaporative water loss was continuously measured using a handheld evaporimeter.
• CEWL was also measured in deceased lizards for comparison.

Main Results:

• CEWL increased significantly with heating and decreased with cooling on the order of seconds.
• A notable difference in CEWL was observed between heating and cooling groups at common body temperatures.
• A positive relationship between CEWL and body temperature was found, consistent in both live and deceased lizards.
• Deceased lizards exhibited more extreme CEWL values compared to live individuals.

Conclusions:

• CEWL demonstrates significant acute lability in response to rapid body temperature fluctuations.
• Both physiological mechanisms and structural adaptations likely contribute to the regulation and plasticity of CEWL.
• These findings have implications for understanding water balance and thermoregulation in reptiles under dynamic environmental conditions.