Plasticity-led evolution: evaluating the key prediction of frequency-dependent adaptation.

Area of Science:

• Evolutionary Biology
• Developmental Biology
• Ecology

Background:

• Plasticity-led evolution proposes that environmental changes induce phenotypic plasticity, which is then refined by natural selection.
• A key prediction is that traits expressed more frequently experience greater selection and adaptive refinement.

Purpose of the Study:

• To test if the frequency of a phenotype's expression correlates with the rate and magnitude of evolutionary change.
• To investigate the role of trait expression frequency in adaptive evolution.

Main Methods:

• Spadefoot toad tadpoles from populations with varying frequencies of a carnivore ecomorph were used.
• Laboratory experiments compared tadpole competition for fairy shrimp, a specialized resource.

Main Results:

• Tadpoles from populations expressing the carnivore ecomorph more frequently were superior competitors for fairy shrimp.
• These tadpoles showed enhanced efficiency in capturing and consuming shrimp, with more exaggerated carnivore traits.
• Carnivore-like traits were present even without the environmental cue, indicating genetic assimilation.

Conclusions:

• The frequency of trait expression is a significant driver of adaptive refinement.
• Findings support the plasticity-led evolution model and general principles of adaptive evolution.
• Genetic assimilation may play a role in extreme cases of plasticity-led evolution.