Linked biological clocks control morning and evening movement in fruit flies

The timing of morning and evening activity in Drosophila melanogaster is regulated by two distinct groups of circadian neurons.

• Morning activity is controlled by ventral lateral neurons expressing the neuropeptide PDF.
• Evening activity arises from a different group of neurons, including dorsal lateral neurons.
• Both neuronal groups can operate independently but are functionally linked.
• Cell-specific ablation techniques reveal the distinct roles of these neuronal populations in regulating daily rhythms.

Simplified