9623479 Rice The Dissertation Research funded by this award will test basic theory on adaptive evolution. Natural selection can be divided into two components - sexual selection (competition by males to fertilize eggs) and non-sexual selection (survival of both sexes and egg production by females). Theory predicts that these two forms of selection can be either reinforcing or antagonistic. If the latter case is common, sexual selection will slow a population's adaptation to a changing environment. Research funded by this award will establish how these two forms of natural selection interact in nature. To do this, a laboratory population of Drosophila melanogaster will be challenged with a new environmental factor, heat stress. The rate of adaptation by the population to the new environment will then be determined with and without sexual selection imposed, providing a direct measure of the regime under which adaptation accrues most rapidly. The relationship between sexual selection and non-sexual selection is of practical concern in all breeding enterprises involving animals or plants (e.g. agriculture, zoological parks, and conservation biology). This research will also shed light on how fast can populations adapt to thermally changing environments. Findings will provide practical information for predicting the ability of insect populations to respond to a protracted and substantial increase in temperature, as anticipated under global climate change.
