Energy Deficit is a Key Driver of Sleep Homeostasis
Sleep and feeding are vital homeostatic behaviors, and disruptions in either can result in substantial metabolic consequences. The precise interplay between these fundamental behaviors remains incompletely understood. Here, we investigate concomitant changes in feeding and sleep behaviors that accompany various types of sleep loss. To understand the circuitry involved in sleep-feeding interactions, we measured changes in sleep and food intake in individual animals, as well as respiratory metabolic expenditure, that accompany behavioral and genetic manipulations that induce sleep loss in Drosophila melanogaster. We found that sleep disruptions resulting in energy deficit through increased metabolic expenditure and manifested as increased food intake were consistently followed by rebound sleep. In contrast, "soft" sleep loss, which does not induce rebound sleep, was not accompanied by increased metabolism and food intake. Our results support the notion that sleep functions to conserve energy and that sleep debt is linked to energy debt. These findings highlight the potential for novel therapeutic approaches to treating sleep or metabolic disorders through the manipulation of the other.