Individual reversible plasticity as a genotype-level bet-hedging strategy

Area of Science:

• Evolutionary biology
• Quantitative genetics
• Ecology

Background:

• Phenotypic plasticity allows organisms to adjust traits in response to environmental changes.
• Costs associated with plasticity can limit its adaptive value.
• Plasticity may also serve as a bet-hedging strategy to stabilize fitness over time.

Purpose of the Study:

• To model the evolution of plasticity, specifically reaction norm slopes, considering both individual optimization and bet-hedging.
• To investigate how environmental grain and time steps influence the optimal level of plasticity.
• To explore the impact of plasticity costs on fitness variation.

Main Methods:

• Development of a mathematical model for the evolution of reaction norm slopes.
• Analysis of scenarios with varying environmental grain and time steps.
• Incorporation of plasticity costs and their effect on fitness variance.

Main Results:

• Increased investment in plasticity (steeper reaction norms) is favored under bet-hedging conditions (coarse environments, fewer time steps) due to reduced fitness variance.
• Individual optimization favors shallower reaction norms in fine-grained environments with many time steps.
• Plasticity costs that increase fitness variation can reverse these patterns.

Conclusions:

• The evolution of optimal plasticity levels depends on a trade-off between short-term individual benefits and long-term bet-hedging advantages.
• Environmental unpredictability and the nature of plasticity costs are key factors shaping adaptive plasticity.
• This framework enhances understanding of plasticity evolution across diverse biological examples.