A new study led by Orie Shafer, Indiana University biology professor and a Linda and Jack Gill Chair at the Gill Institute for Neuroscience, with IU postdoctoral fellow Abhilash Lakshman, Ph.D., and IU undergraduate student Reed Evans, is reshaping how scientists study sleep by revealing that fruit flies experience multiple distinct sleep states rather than a unitary state.
Published in Current Biology, the research uncovers previously hidden mechanisms of sleep regulation and renews the promise of fruit flies as a powerful genetic model for understanding sleep in humans.
“At the heart of this is one of the stars of IU Bloomington Biology, the fruit fly, Drosophila,” Shafer said. The Bloomington Drosophila Stock Center houses the world’s largest collection of fruit flies. “The fruit fly has been a powerhouse for revealing fundamental mechanisms that ultimately prove to be broadly relevant to all animals.”
There are two major mechanisms of sleep regulation. One of them is the clock in your brain, the circadian clock. The other is the homeostatic control of sleep. That is, if you've been awake a long time, you get sleepy. And if you miss a night of sleep, you're even sleepier. The longer you've been awake, the stronger the drive is to sleep. Shafer said, “It's like a temperature homeostat. It's there to ensure the right amount of sleep.”
The study, “Recognition of distinct sleep states in Drosophila uncovers previously obscured homeostatic and circadian control of sleep,” appears online in Current Biology and will be published in the February 23, 2026 issue.
