Seeking voluntary passive movement in flies is play-like behavior

Play-like behaviour (PLB) is pervasive across the animal kingdom, especially in vertebrate species. Invertebrate PLB has been restricted to social or object interaction. Here we examined individual PLB in the vinegar fly Drosophila melanogaster by providing voluntary access to a spinning platform – a carousel. We demonstrate that flies exhibit idiosyncratic carousel interactions that qualify as play-like behaviour. While some flies show spontaneous avoidance, others actively seek stimulation, engaging in repeated, prolonged visits to the carousel. We propose that flies voluntarily expose themselves to external forces to intentionally receive exafferent stimulation. Self stimulation provides an efficient way to improve self-perception via internal model training and can shape multisensory integration.