Local thermal adaptation detected during multiple life stages across populations of Drosophila melanogaster.

Thermal adaptation is typically detected by examining the tolerance of a few populations to extreme temperatures within a single life stage. However, the extent to which adaptation occurs among many different populations might depend on the tolerance of multiple life stages and the average temperature range that the population experiences. Here, we examined local adaptation to native temperature conditions in eleven populations of the well-known cosmopolitan fruit fly, Drosophila melanogaster. These populations were sampled from across the global range of D. melanogaster. We measured traits related to fitness during each life stage to determine whether certain stages are more sensitive to changes in temperature than others. D. melanogaster appeared to show local adaptation to native temperatures during the egg, larval and adult life stages, but not the pupal stage. This suggests that across the entire distribution of D. melanogaster, certain life stages might be locally adapted to native temperatures, whereas other stages might use phenotypic plasticity or tolerance to a wide range of temperatures experienced in the native environment of this species.