Change in relative trait size is a primary mechanism by which adaptation and diversification occurs. This study will rigorously test the hypothesis that selection on ecological performance has produced an observed pattern frequently cited as one of the most compelling cases of adaptation known. Fruit flies vary in wing size such that in cooler environments flies are larger with disproportionately large wings. This study will (1) impose artificial selection on flight performance in warm and cool environments to evolve populations of flies possessing morphology suited to flight at each temperature, (2) assess the adaptive nature of the those flies in flight and survival assays, and (3) determine the strength and pattern of selection acting on each trait. In addition, the proposed work will involve the training of four undergraduates, including individuals from groups that are underrepresented in the sciences.
