Ancestral genetic variation in phenotypic plasticity underlies rapid evolutionary changes in resurrected populations of waterfleas
J. Alex Landy, Alixander Oschmann, Stephan B. Munch, Matthew Walsh
Abstract
Significance It has long been hypothesized that environmentally-induced shifts in phenotype (i.e., “phenotypic plasticity”) are central to adaptation and population persistence. This study tracked evolutionary changes over short time periods by resurrecting populations of waterfleas from lakes in Wisconsin following the invasion of a novel predator. The resurrection approach revealed extensive genetic variation in plasticity in ancestral waterfleas. Such variation provided the opportunity for predator-mediated selection to then drive rapid genetic changes in life history and behavioral traits. Surprisingly, shifts in trait values proceeded in the absence of changes in trait plasticity or the erosion of genetic variation in plasticity. Such results illustrate that ancestral variation in phenotypic plasticity is an important requirement for evolutionary responses to natural selection.