Multiple Environmental Stressors Induce an Adaptive Maternal Effect.
The American Naturalist
|September 24, 2020
Summary
Maternal stress pathways influence offspring aggression in western bluebirds. General stress responses, like the hypothalamic-pituitary-adrenal axis, may help adaptive maternal effects evolve in changing environments.
Area of Science:
- Evolutionary biology
- Behavioral ecology
- Physiological ecology
Background:
- Adaptive evolution requires predictable environmental cues, yet environments are dynamic.
- Adaptive maternal effects, where mothers influence offspring traits, are thought to need reliable cues.
- General maternal pathways may resolve this by responding to various cues.
Purpose of the Study:
- To investigate if maternal stress pathways mediate adaptive maternal effects in western bluebirds.
- To determine if multiple environmental stressors impact maternal physiology and offspring traits.
Main Methods:
- Long-term (18 years) hormone sampling in western bluebirds across different environmental contexts.
- Experimental manipulation of the competitive environment.
- Analysis of maternal corticosterone levels and their influence on offspring aggression.
Main Results:
- Multiple environmental factors affected maternal corticosterone levels.
- Maternal corticosterone influenced a maternal effect on sons' adult aggression.
- This maternal effect was induced by multiple stressors.
Conclusions:
- General maternal physiological pathways, like the hypothalamic-pituitary-adrenal axis, can integrate variable environmental conditions.
- Activation of these general pathways may facilitate the evolution of adaptive maternal effects.
- This provides a mechanism for how complex adaptations evolve despite environmental unpredictability.
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