Original researchIncreased food intake after starvation enhances sleep in Drosophila melanogaster

Feeding and sleep are highly conserved, interconnected behaviors essential for survival. Starvation has been shown to potently suppress sleep across species; however, whether satiety promotes sleep is still unclear. Here we use the fruit fly, Drosophila melanogaster, as a model organism to address the interaction between feeding and sleep. We first monitored the sleep of flies that had been starved for 24 h and found that sleep amount increased in the first 4 h after flies were given food. Increased sleep after starvation was due to an increase in sleep bout number and average sleep bout length. Mutants of translin or adipokinetic hormone, which fail to suppress sleep during starvation, still exhibited a sleep increase after starvation, suggesting that sleep increase after starvation is not a consequence of sleep loss during starvation. We also found that feeding activity and food consumption were higher in the first 10-30 min after starvation. Restricting food consumption in starved flies to 30 min was sufficient to increase sleep for 1 h. Although flies ingested a comparable amount of food at differing sucrose concentrations, sleep increase after starvation on a lower sucrose concentration was undetectable. Taken together, our results suggest that increased food intake after starvation enhances sleep and reveals a novel relationship between feeding and sleep.