How vibrational signals can guide mating behaviour in Scaphoideus titanus

The development of sustainable control methods of insects requires detailed knowledge about the biology of the pest and how it communicates with conspecifics. For example, when developing a mating disruption strategy to control vibrational communicating pest species, it is important to understand the mechanisms of its mating behaviour. We have studied the leafhopper Scaphoideus titanus, which is a vector of the severe phytoplasma grapevine disease Flavescense doreé. In laboratory experiments, males and females were positioned on different parts of the same grapevine cutting and male searching behaviour was recorded with video camera and laser vibrometry. The communication started with an identification phase in which there was an increased male pulse period and random walking after female reply. Thereafter followed a location phase, in which male calls became shorter, with more regular pulse period and correct directional decisions towards the female leaf. When a searching male reached the leaf with the female the perceived intensity of female reply increased significantly and a courtship phase was shown until copulation. With these experiments we have shown for the first time that intensity is an important parameter in vibrational communication of plant-dwelling insects. Different phases of mating behaviour are associated with different levels of perceived signal intensity and accordingly, males adjust the emission of vibrational signals and searching behaviour. Consequently, external interferences may result in loss of information necessary either for identification or location and thus preventing mating. It is possible that mating disruption with vibrations can target successfully the more susceptible behavioural phases of S. titanus