Data and analyses from: Context matters: A meta-analysis of the variable impacts of transgenerational and developmental plasticity on responses to stress

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 in shaping 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. All included studies featured clear “control” and “stress” treatments and a fully factorial design across both parents and offspring. We performed meta-regressions with contextual moderators 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, and under what conditions we may find legacy effects to be adaptive or maladaptive.

We found that there was not a strong, overall effect of either parental or early-life exposure on subsequent offspring performance. However, experimental context (what stressor was used and what traits were measured) as well as biological context (taxonomy, life history traits) were important predictors 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 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.

Methods
This dataset was collected from published research papers as part of a meta-analysis examining the effects of transgenerational and developmental plasticity on organism stress tolerance. Raw data was collected from published manuscripts that fit a pre-determined set of criteria from either 1) raw data provdided by authors in a repository or via personal communicatio, 2) data presented in tables, 3) data mined using the MetaDigitise package in R from figures. These raw data were then analyzed using a meta-analytic model and a series of meta-regression models to determine factors/moderators that significantly contributed to patterns in offspring trait measures. We used two designs and analyzed them separately. The aim for Design A was to determine if there were significant effects of parental treatment (transgenerational plasticity) and offpspring early-life treatment (developmental plasiticity) and their potential interactions on later offspring traits. The aim for Design B was to determine if the timing of parental exposure to stress (in early life or later in life) impacted transgenerational patterns.