Sociosexual interactions with the opposite sex are universal, prevalent even in the lives of solitary animals - presenting a prototype to assess the impact of elemental social interactions on the circadian clock that dictates the daily time of behavioural activity. We employed male Spodoptera littoralis moth as our model, leveraging its adult life singularly dedicated to sex, and hence providing an ideal context to explore the impact of sociosexual cues on the circadian clock. We reveal surprisingly strong influence of pheromone-mediated sociosexual interactions on the circadian rhythms of a solitary insect.