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

Plasticity-led evolution occurs when a change in the environment triggers
a change in phenotype via phenotypic plasticity, and this pre-existing
plasticity is subsequently refined by selection into an adaptive
phenotype. A critical, but largely untested prediction of plasticity-led
evolution (and evolution by natural selection generally) is that the rate
and magnitude of evolutionary change should be positively associated with
a phenotype’s frequency of expression in a population. Essentially, the
more often a phenotype is expressed and exposed to selection, the greater
its opportunity for adaptive refinement. We tested this prediction by
competing against each other spadefoot toad tadpoles from different
natural populations that vary in how frequently they express a novel,
environmentally induced carnivore ecomorph. As expected, lab-reared
tadpoles whose parents were derived from populations that express the
carnivore ecomorph more frequently were superior competitors for the
resource for which this ecomorph is specialized—fairy shrimp. These
tadpoles were better at utilizing this resource both because they were
more efficient at capturing and consuming shrimp and because they produced
more exaggerated carnivore traits. Moreover, they exhibited these more
carnivore-like features even without experiencing the inducing cue,
suggesting that this ecomorph has undergone an extreme form of
plasticity-led evolution––genetic assimilation. Thus, our findings provide
evidence that the frequency of trait expression drives the magnitude of
adaptive refinement, thereby validating a key prediction of plasticity-led
evolution specifically and adaptive evolution generally.