The Free-Running Circasemilunar Period Is Determined by Counting Circadian Clock Cycles in the Marine Midge .

Semilunar rhythms are found in numerous marine organisms, but the molecular mechanism and functional principles of endogenous circasemilunar clocks remain elusive. Here, we explore the connection between the free-running circasemilunar clock and the circadian clock in the marine midge with three different chronobiological assays. First, we found that the free-running circasemilunar period of the adult emergence rhythm in changes linearly with diel T-cycle length, supporting a day-counting mechanism.

Circalunar clocks-Old experiments for a new era.

Circalunar clocks, which allow organisms to time reproduction to lunar phase, have been experimentally proven but are still not understood at the molecular level. Currently, a new generation of researchers with new tools is setting out to fill this gap. Our essay provides an overview of classic experiments on circalunar clocks.