SUMMARY
Hungry animals consistently show a desire to obtain food. Even a brief sensory detection of food can trigger bursts of physiological and behavioral changes. However, the underlying mechanisms by which the sensation of food triggers the acute behavioral response remain elusive. We have previously shown in Drosophila that hunger drives a preference for low temperature. Because Drosophila is a small ectotherm, a preference for low temperature implies a low body temperature and a low metabolic rate. Here, we show that taste sensing triggers a switch from a low to a high temperature preference in hungry flies. We show that taste stimulation by artificial sweeteners or optogenetics triggers an acute warm preference, but is not sufficient to reach the fed state. Instead, nutrient intake is required to reach the fed state. The data suggest that starvation recovery is controlled by two components: taste-evoked and nutrient-induced warm preferences, and that taste and nutrient quality play distinct roles in starvation recovery. Animals are motivated to eat based on time of day or hunger. We found that clock genes and hunger signals profoundly control the taste-evoked warm preferences. Thus, our data suggest that the taste-evoked response is one of the critical layers of regulatory mechanisms representing internal energy homeostasis and metabolism.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
↵4 Lead contact
Main points: 1.We have added data for fructose in Fig. 1 2.We have added statistics (red stars and NS) comparing Tp between fed and refed flies. 3.We have modified the figure for each point to the opened small circles. 4.We have moved the data from Fig. S3 to Fig. 2 and 3. 5.We have added the schematic diagrams depicting behavioral assay in Fig. S1. 6.We have added heatmaps for WT and Gr64f-Gal4>UAS-CsChrimson flies in Fig. S2. 7.We have added Orco1 mutant data in Fig. S4.
