Context matters: A meta‐analysis of the variable impact of transgenerational and developmental plasticity on responses to stress

Abstract Understanding organisms' abilities to adapt and acclimate to stressors in their environments is essential for predicting the distributions and persistence of species and populations during environmental change. Beyond genetic adaptation, prior experiences with a given stressor across life stages can dictate how an individual will fare when exposed to that stressor again. There is now a robust literature on the impacts of parental experiences on offspring traits (transgenerational plasticity), plus an even broader literature on the carry‐over effects of early‐life experience on phenotypic outcomes (within‐generational or developmental plasticity); however, less is understood about the relative strengths of these two forms of plasticity and how they interact to shape stress tolerance. We explored these questions by conducting a meta‐analysis of peer‐reviewed studies that tested both within‐ and transgenerational effects of naturally occurring environmental stressors. In particular, we explored contextual moderators or predictor variables including the traits measured, the type of stressor, taxonomic group and organismal life‐history traits to elucidate patterns and develop a predictive framework for when we should expect to see effects of transgenerational plasticity, within‐generational plasticity, both or neither. We found that there was not a strong or consistent directional effect of either parental or early‐life exposure on subsequent offspring traits. Instead, experimental context (what stressor was used and what traits were measured) as well as biological context (taxonomy, life‐history traits) was an important predictor for understanding the strength and direction of plasticity. We found several contexts where there were meaningful effects of parental and early‐life stress exposure and where there was evidence that these may interact to impact phenotypic and fitness outcomes. Our study highlights the need for careful consideration of context when exploring patterns of plasticity. We hope to underscore the need for additional, fully factorial studies that measure the interaction between these forms of plasticity across a variety of systems and stressors to better understand how stress may carry forward across life stages and generations. Read the free Plain Language Summary for this article on the Journal blog.