Mechanisms For Environmental Temperature And Light Modulation Of Feeding Behavior In Drosophila Melanogaster

Feeding behavior is the action of an animal to obtain the food needed for survival.When to feed is determined to some extent by the animal’s hunger state and is also controlled by the internal circadian clock.Under natural conditions,feeding behavior is influenced by environmental conditions.The mechanisms for how animals adapt their feeding rhythms to environmental changes are largely unknown.Here we used Drosophila as a model to investigate how the nervous system adjusts the feeding rhythms when temperature and light conditions change.We estimated the food intake by quantifying the amount of undigestible blue dye excreted by the flies.We found that when the temperature increased from 25°C to 29°C,flies still maintained the circadian feeding rhythm,but their feeding peak shifted from daytime to nighttime.Mutations in circadian clock genes disrupted this phenomenon,suggesting that increasing temperature alters the phase of feeding rhythms driven by the circadian clock.We also examined the effect of light on feeding behavior.In the wild type and circadian mutants,flies ate more during the day than at night.Increasing the intensity of the light elevated the amount of food intake during the day while reducing nighttime feeding.Red light was less powerful than white light in inducing daytime food intake.These results suggest that light is dominant in driving food intake.Taken together,we found that temperature alters the phase of circadian clock-driven feeding rhythms,whereas light regulates feeding rhythms in a clockindependent manner.Our findings provide new insights into how changes in environmental conditions cause disrupted feeding rhythms and related metabolic diseases.