Aging changes were examined in Drosophila melanogaster. Lifespan was determined in two strains of male and female Drosophila raised at 19 degrees, 24 degrees, and 29 degrees C. The results show an inverse relationship between lifespan and temperature. In addition, lipid peroxidation rates and superoxide dismutase activity were measured in homogenates and phospholipase A2 activity was determined in crude membrane samples prepared from this species. Temperature was found to be directly correlated with the rate of lipid peroxidation in each group. The longest-lived group, wild-type females, exhibited the lowest rate of lipid peroxidation at each temperature; whereas the shortest-lived group, vestigial wing males, displayed the highest rates of lipid peroxidation. Older (40-53 day) vestigial wing males also exhibited significantly higher superoxide dismutase activity than younger vestigial wing males (0-5 day) and higher phospholipase A2 activity than wild-type females of the same age. These results indicate that there is an association between lipid peroxidation rates and lifespan in Drosophila, and that aging changes may include an increase in superoxide dismutase and phospholipase A2 activity. These findings agree with the hypothesis that free radicals are involved in the aging process in Drosophila.