Meeting Abstract

P1.90  Tuesday, Jan. 4  Evolution of membrane acclimation in experimentally evolved populations of Drosophila melanogaster COOPER, Brandon S.*; HAMMAD, Loubna A.; KARTY, Jonathan A.; MONTOOTH, Kristi L.; Indiana University; Indiana University; Indiana University; Indiana University brascoop@indiana.edu

Temperature dramatically impacts the fluidity of cellular membranes. Because membranes play key roles in vital cellular processes, cells must respond to thermal change by adaptively shifting the composition of membranes in heterogeneous environments. Yet, we know very little about how the capacity to alter cellular structure evolves. Models of optimal plasticity predict that the capacity to acclimate physiology during development should evolve when temperature varies across generations. Experimental tests in natural populations of Drosophila melanogaster have failed to support this idea; populations from environments with high and low variation in temperature across generations failed to acclimate their thermal optima of daily fecundity suggesting that populations might be developmentally or genetically constrained. Here, we explicitly evaluate this idea using fifteen experimentally evolved populations of D. melanogaster. These populations have evolved for more than three years in either constant or temporally fluctuating thermal environments. Flies were allowed to develop from egg to adult at 16° and 25°C. We then measured glycerophospholipid content and saturation of fatty acyl chains within the cell membranes of acclimated flies. We predicted that flies evolved in the temporally variable environment should have a higher capacity to alter cellular structure during development than flies evolved in constant environments. Our study represents the first explicit test of the theory and enables us to begin to elucidate the mechanisms and underlying genetics of acclimation.