Abstract
Decision-making under uncertain conditions favors bet-hedging (avoidance of fitness variance), whereas predictable environments favor phenotypic plasticity. However, entirely predictable or entirely unpredictable conditions are rarely found in nature. Intermediate strategies are required when the time lag between information sensing and phenotype induction is large (e.g., transgenerational plasticity) and when cues are only partially predictive of future conditions. Nevertheless, current theory regards plasticity and bet-hedging as distinct entities. We here develop a unifying framework: based on traits with binary outcomes like seed germination or diapause incidence we clarify that diversified bet-hedging (risk-spreading among one’s offspring) and transgenerational plasticity are mutually exclusive strategies, arising from opposing changes in reaction norms (allocating phenotypic variance among or within environments). We further explain the relationship of this continuum with arithmetic mean maximization vs. conservative bet-hedging (a risk-avoidance strategy), and canalization vs. phenotypic variance in a three-dimensional continuum of reaction norm evolution. We discuss under which scenarios costs and limits may constrain the evolution of reaction norm shapes.
Highlights
Changing conditions can promote evolutionary change in various ways (Botero et al, 2015; Tufto, 2015)
We identified the mean phenotype frequency f and the variance composition r as two summary statistics of reaction norms that allow distinguishing between arithmetic mean maximization (AMM), conservative bethedging (CBH), diversified bet-hedging (DBH) and plasticity, and the sum s of the variance components as a measure of phenotypic variance
In section “Arithmetic Mean Maximization, Diversified Bethedging and Conservative Bet-hedging” we described AMM, DBH and CBH as a linear gradient of strategies to cope with a single environment
Summary
Changing conditions can promote evolutionary change in various ways (Botero et al, 2015; Tufto, 2015). When environments are constant throughout an organism’s life time but change from one generation to the phenotypic change can be induced in the offspring generation These are referred to as anticipatory parental effects (Burgess and Marshall, 2014) or intergenerational inheritance (Perez and Lehner, 2019). When environmental fluctuations last for several generations, epigenetic modifications may be integrated into the germ line and affect multiple succeeding generations This is referred to as transgenerational plasticity or non-genetic inheritance (Perez and Lehner, 2019; Adrian-Kalchhauser et al, 2020). For the remainder of the article we will refer to all these irreversible changes as phenotypic plasticity, ignoring the potential physiological constrains that may limit their evolution They all have in common that there is a long delay between information sensing and phenotype induction
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
