Different age-dependent performance in Drosophila wild-type Canton-S and the white mutant w1118 flies

Aging has significant effects on the locomotor performance of insects including Drosophila. Using a protocol for the high-throughput analysis of fly locomotion in a circular arena, we examined age-dependent behavioral characteristics in adult flies. There are widely used wild-type and genetically engineered background lines including the Canton-S strain and the w1118 strain, which has a null mutation of the white gene. Under standard rearing conditions, we found similar survival and median lifespans in Canton-S (50 days) and w1118 (54 days) strains, however, w1118 flies maintained stable body mass for up to 43 days, whereas Canton-S flies gained body mass at young age, followed by a gradual decline. We also tested the behavioral performance of young and old flies. Compared with young w1118 flies (5-10 days), old w1118 flies (40-45 days) had an increased boundary preference during locomotion in small circular arenas, and increased speed of locomotor recovery from anoxia. Old Canton-S files, however, exhibited unchanged boundary preference and reduced recovery speed from anoxia relative to young flies. In addition, old w1118 flies showed decreased path length per minute and reduced 0.2 s path increment compared with young flies, whereas old Canton-S flies displayed the same path length per minute and the same 0.2 s path increment compared with young flies. We conclude that age-dependent behavioral and physiological changes differ between Canton-S and w1118 flies. These results illustrate that phenotypic differences between strains can change qualitatively, as well as quantitatively, as the animals age.