Daytime Color Preference in Drosophila Depends on the Circadian Clock and TRP Channels

Abstract

By guiding animals towards food and shelter and repelling them from potentially harmful situations, light discrimination according to colour can confer survival advantages1,2. Such colour-dependent behaviour may be experiential or innate. Data on innate colour preference remain controversial in mammals3 and limited in simpler organisms4-7. Here we show that when given a choice among blue, green and dim light, fruit flies exhibit an unexpectedly complex pattern of colour preference that changes with the time of day. Flies show a strong preference for green in the early morning and late afternoon, a reduced green preference at midday and a robust avoidance of blue throughout the day. Genetic manipulations reveal that the peaks in green preference require rhodopsin-based photoreceptors, and are controlled by the circadian clock. The midday reduction in green preference in favour of dim light depends on the Transient Receptor Potential (TRP) channels dTRPA1 and Pyrexia (Pyx), and is also timed by the clock. In contrast, blue avoidance is primarily mediated by class IV multidendritic neurons, requires the TRP channel Painless (Pain) and is independent of the clock. With unexpected roles for several TRP channels in Drosophila colour-specific phototransduction, our results reveal distinct pathways of innate colour preference that coordinate the flys behavioural dynamics in ambient light.