INTRODUCTION: Exposure to blue-enriched light from electronic devices is an emergent disruptor of human sleep, especially at particular times of day. Further dissection of this phenomenon necessitates modeling in a tractable model organism.

METHODS: Thus, we investigated the effects of light color on sleep in . We measured sleep in red-eyed Canton-S (CS) and white-eyed flies in baseline 12:12 light/dark conditions and experimental conditions with light-color (blue, red, or green) exposure for all 12 h of daylight or 3 h in the morning or evening.

RESULTS: Blue light reduced daytime and nighttime sleep in CS but not in , potentially indicating a role for the compound eye in blue light's effects on fruit fly sleep. Red light, especially in the evening, reduced sleep during exposure in both strains. Green light had minimal effects on sleep in CS flies, but evening exposure reduced sleep in flies, mimicking red light's effects.

DISCUSSION: In conclusion, light's effects on sleep in are dependent on wavelength and time-of-day. Future studies will aim to dissect these mechanisms genetically.