Temperature Variability Has Limited Effects on Phenotypic Plasticity in Ectotherms-A Meta-Analysis

Area of Science:

• Ecology
• Evolutionary Biology
• Physiology

Background:

• Phenotypic plasticity allows ectotherms to cope with environmental changes.
• Understanding how thermal variability impacts plasticity is vital for predicting species' responses to climate change.

Purpose of the Study:

• To synthesize current knowledge on how thermal variability affects phenotypic plasticity in ectotherms.
• To compare plasticity under constant versus fluctuating temperatures across traits, ecosystems, and plasticity types.

Main Methods:

• Quantitative synthesis of 46 studies on phenotypic plasticity in ectotherms.
• Comparison of plasticity in response to constant and fluctuating temperatures with identical means.
• Analysis across different traits, terrestrial and aquatic ecosystems, and acclimation vs. developmental plasticity.

Main Results:

• Most studies (98%) used diel temperature fluctuations, with data primarily from invertebrates.
• No significant difference in phenotypic plasticity was observed between constant and fluctuating temperature environments.
• A minor effect of fluctuating temperatures was noted on developmental time.

Conclusions:

• Phenotypic plasticity in ectotherms is more strongly influenced by shifts in mean temperatures than by temperature fluctuations.
• Longer-term temperature changes are likely the dominant factor driving plastic responses in ectothermic animals.