PHENOTYPIC PLASTICITY AND SELECTION IN DROSOPHILA LIFE-HISTORY EVOLUTION .2. DIET, MATES AND THE COST OF REPRODUCTION

While it is commonplace for biologists to use the response to environm ental manipulation as a guide to evolutionary responses to selection, the relationship between phenotypic plasticity and genetic change is n ot generally well-established. The life-histories of laboratory Drosos phila populations are among the few experimental systems which simulta neously afford information on phenotypic plasticity and evolutionary t rajectories. We employed a combination of two replicated selectively d ifferentiated stocks (postponed aging stocks and their controls; 10 po pulations in total) and two different environmental manipulations (nut rition and mating) to explore the empirical relationship between pheno typic plasticity and evolutionary trajectories. While there are a numb er of parallels between the results obtained using these two approache s, there are important differences. In particular, as the detail of th e biological characterization of either type of response increases, so their disparities multiply. Nonetheless, the combination of environme ntal manipulation with evolutionary divergence provides valuable infor mation about the biological connections between life-history, calorie reserves, and reproductive physiology in Drososphila.