Song modification in the Orthoptera I. Proclamation songs of Platycleis spp. (Tettigoniidae)

Orthopteran song terminology is briefly reviewed taking into account new proposals concerning the term ‘chirp’ by Broughton (1976). The song of Platycleis intermedia is analysed in detail. Synchronous or unison singing between conspecifics of this species is maintained, despite ambient temperature differences, by the individual at the lower temperature instantaneously extending its echeme interval. The normal songs of P.afinis, P.falx, P.sabulosa and P.albopunctata are described and compared with each other and with the song of P.intermedia. The songs of all five species are similar at the syllable level but different at the echeme level. It appears to be these similarities and differences that are responsible for song modification on the part of P.intermedia when it hears the song of one of the other four species.