No detectable effect of P2 neurons on female post-mating changes in sleep and feeding in Drosophila melanogaster.

UNLABELLED: In many insects, females exhibit behavioral changes after mating. This plasticity can be mediated by interactions between male-derived seminal fluid proteins (SFPs) and the female nervous system. The Drosophila melanogaster seminal fluid protein Sex Peptide (SP) causes mated females to sleep less during the day and consume more food than unmated females, among other behavioral changes. Although the SP-sensing neural circuits that convey information to the female's brain are known, the downstream neurons that affect post-mating behaviors remain unknown. P2 neurons in the fly's central brain are good candidates for regulating post-mating changes in sleep and food consumption, as they express feeding- and sleep-responsive neuropeptide F (NPF), directly innervate the fly's sleep center (the dorsal fan-shaped body, dFB), and are responsible for social-isolation-induced changes in sleep and food consumption. Using the GAL4/UAS system, we activated or silenced P2 neurons in mated and unmated females. We measured sleep duration using Drosophila Activity Monitors (DAM) and food consumption using Capillary Feeder (CAFE) and blue-dye assays. We found that P2-neurons are not responsible for post-mating changes in sleep and food consumption: mated females slept less during the day and ate more compared to unmated females irrespective of P2 neuron perturbation. Together, these results indicate that P2 neurons are unlikely to be primary downstream neurons through which male-transferred SP regulates post-mating sleep and food consumption. Future studies could determine whether P2 neurons regulate other post-mating behaviors or modulate sleep and feeding behaviors in a context-dependent manner. ARTICLE SUMMARY: Post-mating female Drosophila melanogaster sleep less and consume more food, initiated by male-transferred Sex Peptide. But the neurons involved in these post-mating behavioral changes are unknown. P2 neurons may modulate post-mating sleep and food consumption, similar to their known role in a social-isolation context. Ectopic activation and silencing of P2 neurons did not affect post-mating female sleep and food consumption: mated females slept less and consumed more food than unmated females. This study eliminates P2 neurons as targets of female post-mating sleep and feeding, thereby opening new avenues to investigate the roles of other neurons in modulating these post-mating behaviors.