Drosophila melanogaster flies communicate using substrate-borne vibrations during courtship. Caroline C. G. Fabre^1*, Berthold Hedwig², Graham Conduit², Peter A. Lawrence², Stephen Goodwin³, José Casal². 1) Department of Zoology, Cambridge University and Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, United Kingdom; 2) Department of Zoology, Cambridge University, Cambridge, United Kingdom; 3) Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, United Kingdom.

   Courtship in Drosophila melanogaster consists of a series of stereotyped actions by the male to first assess the female's suitability and then elicit her acceptance of copulation, which is signaled by her ceasing to walk. The male and female communicate via vision, air-borne sounds and by pheromones, but it remained unclear what cues trigger female immobility. We describe a further component of Drosophila courtship behaviour that has, surprisingly, been overlooked. We show by video recordings and laser vibrometry that the abdomen of the male vibrates rhythmically ("quivers") to generate substrate-borne vibrations that have a repetition rate of about 6 pulses per second. We present evidence that the female stops walking and becomes receptive mainly because she senses these vibrations and not, as had previously been suggested, as a response to the air-borne song produced when the male extends and flutters one wing. We also show that the neural circuits expressing the sex determination genes fruitless and doublesex are required for the quivering behaviour. Moreover, we show that these abdominal quivers and associated vibrations, as well as their presumed effect on female receptivity, are conserved in other Drosophila species. Substrate-borne vibrations are an ancient form of communication that is widespread in invertebrates and vertebrates. We are now also investigating the neuromuscular circuitry responsible for the generation of these substrate-borne signals and the sensory systems needed for their reception.