Nighttime sleep modulates mechanosensory habituation in Drosophila

Organisms must focus their attention on ethologically relevant stimuli to maximise survival and reproduction. This is achieved, in part, through a process termed habituation, in which responses to repeated or constant sensory inputs are sequentially dampened, favouring robust responses to novel stimuli. Prior investigations in the fruit fly, Drosophila , have uncovered genes and neural mechanisms that facilitate habituation. However, these works have primarily focused on habituation to visual, olfactory, and gustatory, stimuli. In contrast, neurogenetic processes promoting habituation to mechanosensory stimuli have been less studied. Here we develop an automated system that yields long-term analogue measurements of mechanosensory habituation in adult fruit flies. Using this platform, we reveal a role for the neuronal calcium sensor Neurocalcin in habituation to mechanical stimuli. Loss of Neurocalcin disrupts nighttime but not daytime sleep, particularly under long-night conditions. Mimicking a method used to treat insomnia, we show that compressing nighttime duration restores consolidated night sleep in Neurocalcin mutants. Surprisingly, this manipulation also renormalises mechanosensory habituation in this background, suggesting a link between sleep and mechanosensory habituation. Indeed, we show that limiting night sleep duration in wild type flies similarly impairs habituation to mechanosensory stimuli. Collectively, our findings reveal a previously unappreciated link between nighttime sleep and mechanosensory habituation in Drosophila .