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 environmental manipulation as a guide to evolutionary responses to selection, the relationship between phenotypic plasticity and genetic change is not generally well-established. The life-histories of laboratory Drososphila populations are among the few experimental systems which simultaneously afford information on phenotypic plasticity and evolutionary trajectories. We employed a combination of two replicated selectively differentiated stocks (postponed aging stocks and their controls; 10 populations in total) and two different environmental manipulations (nutrition and mating) to explore the empirical relationship between phenotypic plasticity and evolutionary trajectories. While there are a number of parallels between the results obtained using these two approaches, there are important differences. In particular, as the detail of the biological characterization of either type of response increases, so their disparities multiply. Nonetheless, the combination of environmental manipulation with evolutionary divergence provides valuable information about the biological connections between life-history, calorie reserves, and reproductive physiology in Drososphila.