Predator-induced Contemporary Evolution, Phenotypic Plasticity, and the Evolution of Reaction Norms in Guppies

An increasingly large number of studies have demonstrated the ability of populations to undergo contemporary or rapid evolution. Little explored in this regard is the role of phenotypic plasticity, although it can influence ecoevolutionary dynamics and hence evolutionary rates. Here we quantify the evolution of life history and plasticity in Trinidadian guppies transplanted from high to novel low predation environments. Common-garden results show that after only nine years, or 13-27 generations, the introduced guppies have diverged from their ancestral population in both litter size and offspring weight and in the plastic response of both traits to food availability. Given these findings, it is clear that local adaptation includes both changes in mean traits and changes in plasticity.