S6-2.2 Sunday, Jan. 6 Plasticity, selection, and the potential for adaptation in newly established populations GHALAMBOR, C.K.*; HANDELSMAN, C.A.; RUELL, E.W.; Colorado State. Univ.; Colorado State. Univ.; Colorado State. Univ. email@example.com
Novel environments often impose directional selection for a new phenotypic optimum. However, new environments can also be a source of phenotypic variation by inducing plasticity and changing the distribution of phenotypes exposed to selection. Plasticity can either be cogradient, where the plastic response is in the same direction favored by selection, or countergradient, where the response deviates from the direction of selection. Cogradient plasticity is thought to be adaptive, as it provides a better pairing between the phenotype and local ecological conditions, but results in weaker directional selection. In contrast, countergradient plasticity is thought to be non-adaptive, as there is a greater mismatch between the expressed phenotype and the optimum favored by selection, resulting in strong directional selection. Thus, understanding how phenotypic plasticity and selection in new environments jointly shape suites of morphological, physiological, and behavioral traits is critical to predicting evolutionary responses and population differentiation. Here we review plastic responses in a diversity of traits for Trinidadian guppy populations adapted to high and low predation environments. Specifically, we examined plasticity in response to the presence or absence of predator cues during development and suggest that the type of plasticity a trait exhibits can be used to predict how it will respond to selection.