Münster Drosophila Mini-Symposium

The circadian clock allows organisms to stay in sync with their ecological niche. Virtually, all organisms from bacteria to humans, have an endogenous circadian clock that ticks with a period of about 24h. In order to stay synchronised, the circadian clock uses rhythmic environmental parameters (also called Zeitgeber) for its resetting (entrainment), the main ones being light and temperature. However, both light and temperature varies in an unpredictable manner and depending on the time of day, organisms can respond differently to these changes. How does the circadian system distinguish between Zeitgeber and non-Zeitgeber input?
To tackle this important question and yet still unresolved today, I am entraining the flies using temperature cycles (25°C-16°C) as Zeitgeber and study how the light input modulates the rhythmic and synchronised locomotor activity pattern. Both the canonical visual pathway and the circadian blue light photoreceptor CRYPTOCHROME can entrain to light-dark cycle the circadian clock in the brain and synchronised the locomotor activity. However, we do not know whether and how the light information they are providing can be taken as a non-Zeitgeber input.