Circadian clocks coordinate physiology and behavior with the daily light-dark cycle through dedicated neuronal outputs. In Drosophila, egg-laying is a reproductive behavior regulated by both mating status and the circadian clock. The lateral posterior neurons (LPNs) constitute a small subset of circadian clock neurons in Drosophila. Using the Drosophila hemibrain connectome, we recently identified reciprocal synaptic connections between LPNs and inhibitory oviposition neurons (oviINs), suggesting that LPNs may provide circadian input to the reproductive circuitry. Here, we investigated the contribution of LPNs to the circadian and reproductive regulation of egg-laying. We found that disruption of the molecular clock specifically in LPNs does not affect the daily rhythm of oviposition, indicating that these neurons are dispensable for circadian timing of egg-laying. In contrast, manipulating LPN neuronal activity markedly alters female fecundity, demonstrating that LPNs selectively regulate reproductive output rather than its temporal organization. These results suggest that LPNs contribute to the neural control of female reproductive output independently of the mechanisms regulating the daily timing of egg-laying.
