Fruit flies sleep, but some individual flies hardly rest at all, according to a study published recently in Science Advances. In contrast to the devastating effects seen among other animals when they experience sleep deprivation, fruit flies handle it pretty well.
“[W]e report two surprising findings . . . challenging the notion that sleep is a vital necessity: the discovery of virtually sleepless flies and the finding that chronic sleep restriction in Drosophila melanogaster has notably less pronounced effects on longevity than previously thought,” the authors write in their paper.
For one part of the project, the researchers videotaped fruit flies behaving in the lab for four days and had a machine-learning program calculate the time the flies were moving or were still, presumably asleep. Typically, the flies slept several hours, but there was great variation among individuals, with some consistently sleeping only a few minutes each day. “[F]lies (and, in fact, animals) sleeping as little as few minutes a day were never identified before,” the authors write.
To see how flies would fare if they were forced to stay awake, the researchers rigged a tube so that it would spin if the fly settled down, thereby flipping it over and nudging it awake. This went on for the duration of the flies’ lives. Again, surprising results: sleep-deprived males lived just as long as unperturbed males, while sleep-deprived females lived slightly shorter lives, 37.5 days on average compared with 41 days among female flies allowed to sleep.