Behavioral plasticity offers one mechanism through which organisms can immediately respond to changes in their environment. But why are some individuals more plastic than others? What determines the extent and direction of behavioral plasticity? EERREC REU students will study how experience with early-life stress can shape the expression of behavioral plasticity and thus an individual's ability to cope with later environmental change. Using the naturally clonal fish, the Amazon molly (Poecilia formosa), will allow students to pinpoint the effects of plasticity while controlling for genetic variation. Students will observe live animals, apply ecologically relevant stressors, and perform behavioral coding and data analysis.