Phenotypic plasticity can allow organisms to respond to environmental changes by producing better matching phenotypes without any genetic change. Because of this, plasticity is predicted to be a major mechanism by which a population can survive the initial stage of colonizing a novel environment. We tested this prediction by challenging wild Drosophila melanogaster with increasingly extreme larval environments and then examining expression of alcohol dehydrogenase (ADH) and its relationship to larval survival in the first...