Sleep parameters during night and day in all flies. Values are mean + SEM (eleven 12-hour intervals averaged per each fly, and then averaged across all flies). The number of flies tested at each age is shown below each bar. Genotype (g) effects were tested across all ages (Kruskal-Wallis test, p < 0.05). Horizontal bars indicate significant age-related effects within each genotype (Friedman test followed by Wilcoxon signed-rank test, p < 0.05).