TY - JOUR T1 - Sleep in populations of <em>Drosophila melanogaster</em> JF - eneuro JO - eneuro DO - 10.1523/ENEURO.0071-15.2015 SP - ENEURO.0071-15.2015 AU - Chang Liu AU - Paula R. Haynes AU - Nathan C. Donelson AU - Shani Aharon AU - Leslie C. Griffith Y1 - 2015/08/13 UR - http://www.eneuro.org/content/early/2015/08/13/ENEURO.0071-15.2015.abstract N2 - The fruit fly Drosophila melanogaster is a diurnal insect active during the day with consolidated sleep at night. Social interactions between pairs of flies have been shown to affect locomotor activity patterns, but effects on locomotion and sleep patterns have not been assessed for larger populations. Here, we use a commercially available Locomotor Activity Monitor (LAM25H) system to record and analyze sleep behavior. Surprisingly, we find that same-sex populations of flies synchronize their sleep/wake activity, resulting in a population sleep pattern which is similar, but not identical to that of isolated individuals. Like individual flies, groups of flies show circadian and homeostatic regulation of sleep as well as sexual dimorphism in sleep pattern and sensitivity to starvation and a known sleep-disrupting mutation (amnesiac). Populations of flies, however, exhibit distinct sleep characteristics from individuals. Differences in sleep appear to be due to olfaction-dependent social interactions and change with population size and sex ratio. These data support the idea that it is possible to investigate neural mechanisms underlying the effects of population behaviors on sleep by directly looking at a large number of animals in laboratory conditions.Significance Statement: Most species live in an interactive environment in their natural habitats, and sleep can be affected by social cues. Although flies have been widely used to understand the mechanisms of sleep in recent years, sleep in large populations has not been systematically studied. Here we report both similarities and differences between sleep in populations of flies compared to individuals as well as provide a new method for the study of social behavior under constant environmental conditions. ER -