[Show abstract][Hide abstract] ABSTRACT: The identification of differential patterns of change across the lifespan in quantitative traits is of abiding interest in the biological and gerontological research communities. These differential phenotypic patterns in complex systems illuminate developmental processes and form the foundation for the identification of putative biomarkers of aging. The goal of the present study was to explore changes in locomotor activity through the lifespan of Drosophila melanogaster. A replicated serial cross-sectional sampling design was used to test activity in five genetically independent inbred strains at 7, 14, 21, 28, 35, and 42 days of age. Differences were observed in activity level across ages and strains, suggesting that patterns of activity throughout the lifespan of D. melanogaster are influenced by genetic factors. Observed sex differences in change in activity level indicate that the aging processes may proceed differently in males and females.