The Circadian Clock Gates Drosophila Adult Emergence By Controlling The Timecourse Of Metamorphosis

Significance In holometabolous insects, the circadian clock restricts the time of adult emergence. Although this daily gating of behavior is one of the first circadian rhythms to be studied, little is known about the mechanism underlying the gating process itself. Here, we show that the circadian clock imposes a daily rhythmicity to the pattern of adult emergence by controlling the timing of the completion of metamorphosis. Thus, our findings reveal that the basis of gating is a developmental process and not an acute on/off activational switch and fundamentally changes our understanding of how this circadian control is accomplished. It also provides evidence of a mechanism by which the circadian clock imposes a daily rhythmicity to behavior through the control of the pace of development.