The marine midge Clunio marinus times its life cycle to the rhythm of the tides by means of circadian and circalunar clocks. While circadian clocks are well understood the molecular level, the molecular basis of circalunar clocks is entirely unknown.

The Baltic species C. balticus has diverged from C. marinus in the last 8000 years and in the absence of tides in the Baltic Sea it has lost the circalunar clock. This project will investigate differences between both species in order to get insights into the molecular basis and evolution of circalunar clocks. Samples will be taken at Askö and we will establish a lab culture of C. balticus to compare it to C. marinus.

There are regular cycles in nature that all organisms can rely on: tides, the change of day and night, the moon phases and the seasons. Organisms can predict these regular cycles by using so-called biological clocks. Circadian clocks, which control daily rhythms, are well examined in model organisms like mice or fruit flies. Circalunar clocks on the other hand, which control rhythms according to the moon phases, are still not understood at the molecular level.

Clunio marinus is a model organism to study circalunar clocks. Interestingly, in the Baltic sea, where tides are absent, the species Clunio balticus evolved, which has lost its circalunar clock. During mating season the adult animals emerge from the bottom of the sea and mate every night after sunset. Comparing C. marinus and C. balticus can give insights into the molecular basis and evolution of circalunar clocks.

For more information:
Nico Fuhrmann, Max Planck Institute for Evolutionary Biology