Pair formation mediated by substrate-borne vibrations: how signal spectral properties can drive the mating behaviour in small insects

The ability to identify and locate conspecifics depends on reliable transfer of information between emitter and receiver. Vibrational signals are known to encode information about identity in their temporal pattern and can also enable localization of a partner. Much less is known about mechanisms of decision making in the context of mating behaviour. In Auchenorrhyncha (Hemiptera: Fulgoromorpha and Cicadomorpha) pair formation is commonly accompanied with the emission of calling and courtship signals and constant exchange of information between sexes in a duet. Different signals appear to be behaviourally specific; however, what elicits the shift from one signal type to another one in a certain context is still unknown. Here we present our studies about pair formation in two model species, the leafhopper Scaphoideus titanus and the planthopper Hyalesthes obsoletus. We investigated how individuals responded to different mating signals played back in plant tissues after manipulation of spectral components (intensity and frequency pattern). We showed that even minor changes in the signal spectral composition could radically modify the behavioural response of individuals and, consequently, that decision making was related to the signal partner perception. Our conclusion is that, in Auchenorrhyncha, different phases of pair formation, from the establishment of a duet to the partner location, can be regulated by emission/perception of substrate-borne signals and that mating success can strongly depend on the quality of these signals.