Prior hormetic priming is costly under environmental mismatch

Area of Science:

• Environmental science
• Stress biology
• Evolutionary biology

Background:

• Hormetic environmental priming of stress responses is recognized to enhance resilience to later life stress.
• Phenotypic adjustments to environmental stressors can incur costs, especially if future conditions mismatch the priming environment.

Purpose of the Study:

• To investigate the consequences of hormetic priming to mild heat stress in early life on subsequent survival under different adult stress conditions.
• To understand the adaptive significance and potential costs associated with hormetic stress responses.

Main Methods:

• Experimental manipulation of early life environment with mild heat stress.
• Exposure to different environmental conditions (heat stress or no stress) in adulthood.
• Assessment of survival rates as the primary outcome measure.

Main Results:

• Hormetic priming to mild heat stress in early life significantly increased adult survival exclusively when heat stress was re-experienced in adulthood.
• Conversely, early life heat stress priming reduced adult survival when the adult environment did not involve heat stress.

Conclusions:

• The benefits of hormetic priming are conditional on the match between the priming and subsequent environments.
• The observed costs of mismatched priming explain the evolutionary regulation of stress response systems, preventing constant upregulation and favoring adaptive adjustments.