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 (50days) and w1118 (54days) strains, however, w1118 flies maintained stable body mass for up to 43days, 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 (5-10days), old w1118 flies (40-45days) 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 0.2s path increment compared with young flies, whereas old Canton-S flies displayed the same path length per minute and the same 0.2s 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.