The adaptive advantage of phenotypic memory in changing environments

TLDR

The study investigates the adaptive value of carry‑over effects—phenotypic persistence across generations—and proposes extending plasticity to include temporal stability across clonal and sexual generations. Using a simple model, the authors compare three organismal strategies—non‑inducible, fully inducible, and intermediate carry‑over—in fitness across three environments, and extend plasticity to include temporal stability across clonal and sexual generations. Analytical and simulation results demonstrate that carry‑over effects confer an advantage in stochastic environments, acting as an adaptive mechanism bridging short‑term individual adaptations and long‑term evolutionary changes.

Abstract

The adaptive value of carry-over effects, the persistence of induced phenotypes for several generations despite the change in the conditions that first induced these phenotypes, is studied in the framework of a simple model. Three different organismal strategies - non-inducible (genetic), completely inducible (plastic), and intermediate (carry-over) - are compared in fitness terms within three different environments. Analytical results and numerical simulations show that carry-over effects can have an advantage in stochastic environments even over organisms with high adaptive plasticity. We argue that carry-over effects represent an adaptive mechanism on the ecological timescale that fills the gap between short-term individual adaptations and long-term evolutionary adaptations. An extension of the concept of plasticity to incorporate the time dimension and include the stability of induced phenotypes through both clonal and sexual generations, is suggested.