Abstract: Hyalesthes obsoletus Signoret is a vector of the stolbur phytoplasma (group 16SrXIIA),causal agent of the grapevine disease ‘Bois Noir’. In planthoppers the intraspecificcommunication is based on substrate-borne vibrational signals. The aim of this study was toinvestigate the mating behaviour of H. obsoletus. Vibrational signals were detected from nettlecuttings by laser vibrometer. Both male and female can start the mating process by the emissionof calling signals. The male calling signal is a single short syllable (Male Syllable 1) whereas thefemale’s is a train of pulses of variable length. Initially, the male/female duet is based on thealternating emission of calling signals (recognition phase). In a second step, the male startsemitting long syllable trains (male courtship signal) in which the female occasionally insertssingle pulses (courtship phase). The male courtship signal is made of two different types ofsyllables (Male Syllable 2 and 3), the switch from one to another often triggered by the emissionof a female pulse. When partners are in close vicinity the male emits a specific pre-copula signalthat precedes the copula (pre-copula phase). Rivalry tests, either pairs of males or trios, showed astrong competition between males, expressed in the form of chorusing, rivalry signals andaggressiveness.