Overview
This lecture covers a study on how desert short-horned lizards adjust their use of light environments through phenotypic plasticity when transplanted to different elevations, offering insights into their potential resilience against climate change.
Thermoregulatory Behaviour in Lizards
- Thermoregulatory behaviour allows ectotherms to maintain preferred body temperatures in varying environments.
- In lizards, this behaviour often involves selecting specific light environments to regulate body temperature.
- Phenotypic plasticity, or the ability of an organism to alter its physiology or behaviour in response to environmental changes, underlies this thermoregulatory variation.
Study Design: Reciprocal Transplant Experiment
- Researchers studied two populations of Phrynosoma hernandesi (desert short-horned lizards) at low (warm) and high (cool) elevations.
- Lizards from each population were transplanted to the opposite elevation (reciprocal transplant).
- Light-environment use was continuously recorded before and after the transplant in both populations.
Key Findings
- After being moved to a novel climate, transplanted lizards quickly adjusted their light-environment use to match the local lizards.
- This immediate adjustment demonstrates phenotypic plasticity in thermoregulatory behaviour.
- The ability to rapidly change behaviour may buffer lizard populations against the impacts of climate warming.
Implications for Climate Change
- Phenotypic plasticity in thermoregulatory behaviour suggests these lizards may cope with increasing temperatures by altering their light-environment use.
- Accurate models predicting outcomes of climate change for ectotherms should incorporate this behavioural flexibility.
Key Terms & Definitions
- Ectotherm — an organism that relies on external sources to regulate its body temperature.
- Thermoregulatory behaviour — actions taken by organisms to control their internal temperature.
- Phenotypic plasticity — the capacity of an organism to alter its behaviour or physiology in response to environmental changes.
- Reciprocal transplant — an experiment where organisms are swapped between different environments to study adaptation or plasticity.
Action Items / Next Steps
- Review details of reciprocal transplant experimental design.
- Read about implications of phenotypic plasticity for climate change resilience in ectotherms.