A Random Walk in the Park: An Individual-Based Null Model for Behavioral Thermoregulation

Area of Science:

• Ecology
• Animal Behavior
• Physiological Ecology

Background:

• Behavioral thermoregulation is crucial for ectotherms, directly influencing performance and fitness.
• Habitat thermal quality significantly impacts the energetic costs and effectiveness of thermoregulation.
• Understanding the interplay between environment and behavior is key to predicting species' responses to changing climates.

Purpose of the Study:

• To develop a null model for behavioral thermoregulation to assess habitat thermal quality.
• To quantify the 'thermal benefit' of thermoregulation as a proxy for fitness.
• To compare thermal quality and thermal benefit in two distinct tropical habitats for lizards.

Main Methods:

• A null model simulating a random walk in a thermal landscape was developed to predict body temperature.
• Thermal quality was defined as a temporally dynamic distribution, an ergodic property of random walks.
• Thermal benefit was calculated by linking body temperature to performance curves, and applied to real lizard data.

Main Results:

• The model successfully estimated habitat thermal quality and the impact of behavioral thermoregulation on body temperature.
• Lizard thermal benefit varied between the two tropical habitats studied.
• The model revealed daily shifts in thermoregulatory effort, from active thermoregulation to passive thermal conformity.

Conclusions:

• The random walk model provides a robust framework for evaluating habitat thermal quality and thermoregulatory effectiveness.
• Behavioral thermoregulation significantly influences lizard fitness through its impact on body temperature and performance.
• This approach offers insights into the adaptive strategies of ectotherms in complex thermal environments.