Mueller 9410281 This proposal describes experiments for studying the evolution of population stability. The experimental research described will utilize Drosophila melanogaster as a model organism. Specifically, 20 populations will be created to study the evolution of life histories that affect the stability of a population around its carrying capacity. Two source populations will be used: the UU populations that have been kept at low larval and adult densities and the CU populations that have been kept at high larval and low adult density. Each of these populations, which is replicated fivefold, will be kept in two different environments: the HL environment provides high levels of food for larvae but low levels to adults, and the LH environment, which provides low levels of food to the larvae and high levels to the adults. The LH environment has been shown previously to produce cycles about the equilibrium point. The stability properties of these populations will be determined in the LH environment at the start of the experiment and after 24 generations of selection. Additionally the populations will be sampled periodically for life history characters that are known to respond to density-dependent natural selection that are important for the stability of the population. These characters include, (1) larval feeding rates, (2) larval pupation height, and (3) female fecundity in the LH environment at high adult densities.
