Costs of phenotypic plasticity.

Area of Science:

• Evolutionary Biology
• Ecology
• Developmental Biology

Background:

• Phenotypic plasticity allows organisms to adapt to different environments, but the costs associated with this ability are not well understood.
• Evolutionary models suggest plasticity costs could limit the development of optimal phenotypes, yet empirical evidence is scarce.

Purpose of the Study:

• To investigate the fitness costs of phenotypic plasticity in larval wood frogs (Rana sylvatica).
• To determine if increased plasticity leads to reduced growth, increased developmental instability, or limits extreme phenotype expression.

Main Methods:

• Larval wood frogs were reared in outdoor mesocosms and exposed to dragonfly predators (Anax longipes).
• Behavioral, morphological, and life-historical traits were measured to assess predator-induced changes and plasticity.
• Fitness effects of plasticity were evaluated across different sibships and environments.

Main Results:

• Predators induced reduced activity, larger tails, and smaller bodies in tadpoles, leading to decreased growth and development.
• Increased plasticity had varied fitness effects (positive, negative, or none) on tadpole mass, development, and survivorship.
• No relationship was found between increased plasticity and developmental instability; highly plastic genotypes produced the most extreme phenotypes.

Conclusions:

• Costs of phenotypic plasticity may be common in nature and significantly influence the evolution of adaptive traits in variable environments.
• Plasticity does not inherently limit an organism's ability to produce extreme phenotypes when needed.
• This research provides empirical support for the pervasive impact of plasticity costs on evolutionary trajectories.