Bidirectional regulation between circadian feeding behavior and specialized midgut clocks in Drosophila

Feeding is a fundamental animal behavior. Increasing evidence suggests that the timing of food intake--rather than the amount or quality alone--contributes to maintaining health. Although mistimed eating can reset peripheral clocks and desynchronize them from central pacemakers to affect physiology and metabolism, how peripheral clocks can in turn shape rhythmic feeding behavior is less well understood. Here, we investigated the contribution of peripheral clocks to circadian feeding behavior in Drosophila males. Using high-resolution feeding assays combined with complementary analytical approaches that assess both rhythmicity and time-resolved dynamics, we examined the roles of distinct peripheral cell types in feeding regulation. This study reveals the involvement of midgut enteroendocrine cells (EECs) and enterocytes (ECs) in maintaining the stability and strength of feeding rhythms, whereas the fat body clock modulates baseline levels of food intake. Beyond serving as an output behavior of circadian rhythms, feeding also acts as an effective behavioral Zeitgeber that drives molecular clocks. In the absence of the dominant Zeitgeber--light--midgut oscillations decay during prolonged ad libitum feeding in constant darkness, whereas feeding/fasting cycles enable the autonomous persistence of clock oscillations in EECs but not in ECs. These findings are suggestive of regulatory feedback between midgut EECs and feeding, highlighting how timed feeding or dietary interventions could influence metabolic health via specialized gut cells.