Figure 2.

Populations of flies exhibit sleep patterns distinct from individual flies. A, Individual fly sleep for males and females. B, Sleep in populations of males and females. C, Quantification of total sleep from A and B. Individual males slept more than females. In populations males slept longer during the day, but less at night. D, Activity levels during wake periods. Males had more beam breaks than females in populations. E, Number of sleep episodes. Individual females had more sleep episodes than males, but populations were indistinguishable. F, Mean episode length. Females had shorter episodes than individual males, but no significant difference was detected in populations. G, Sleep Latency. Individual male flies took shorter time to fall asleep after light transitions than individual female flies, but no significant difference was found between populations of males and females. n = 32 for individuals and n = 8 groups for populations. Statistically similar groups are marked by the same letter, with different letters indicating significant differences between groups. F, female; M, male; ZT, Zeitgeber time.