Acclimatization in the physiological performance of an introduced ectotherm

Area of Science:

• Ecology
• Evolutionary Biology
• Physiology

Background:

• Phenotypic flexibility aids species in adapting to novel environments, potentially facilitating range expansion.
• Behavioral thermoregulation can be costly; physiological acclimatization offers an alternative for maintaining performance.
• The northern curly-tailed lizard (Leiocephalus carinatus) is an introduced species established in Florida.

Purpose of the Study:

• To investigate seasonal variations in the morphology and performance of Leiocephalus carinatus.
• To determine the role of phenotypic flexibility, specifically reversible acclimatization, in the success of introduced species.

Main Methods:

• Measured bite force and thermal sensitivity of sprinting in Leiocephalus carinatus during winter and spring.
• Generated thermal reaction norms to analyze physiological performance across temperatures.
• Compared performance metrics at common temperatures and assessed seasonal morphology-performance relationships.

Main Results:

• Seasonal variations in physiological performance were detected, particularly when using thermal reaction norms.
• Lizards in spring exhibited faster sprinting and higher temperature tolerance.
• Winter lizards maintained high performance across a broader temperature range, unlike spring lizards.
• Sprint and bite force did not differ seasonally at a common temperature.
• No seasonal links between morphology and performance were found.

Conclusions:

• Leiocephalus carinatus demonstrates reversible acclimatization, enabling high performance across seasons outside its native thermal range.
• Thermal physiology plasticity may mitigate the effects of suboptimal temperatures without relying on behavioral thermoregulation.
• Evaluating performance using reaction norms is crucial for understanding introduced species' ecological impacts.