Songs and the function of song elements in four duetting bushcricket species (ensifera, phaneropteridae, Barbitistes)

The structure of male songs and the timing of female replies with respect t o the male songs are described for four species of the palaearctic bushcric ket genus Barbitistes (B. constrictus, B. ocskayi, B. serricauda, B. yersin i). In a male song, 3 to 16 syllables form a chirp followed by a "trigger s yllable" after a longer interval. The trigger syllable releases a female re ply with a latency of 30 to 50 ms in all four species. In B. serricauda son gs, there is no clearly separated trigger syllable. Instead, the first syll able of a chirp functions as a trigger syllable. Some B. serricauda males m ay produce a short female-type syllable just at the moment, when a female w ould reply. The possible function of such a syllable is acoustical mimicry. When comparing at least two song parameters, each species occupies a speci fic combination of values. According to the overlap of parameters a close p hylogenetic relationship between B. constrictus and B. serricauda and betwe en B. ocskayi and B. yersini is assumed. This interpretation is compared wi th a hypothesis based on morphological investigations.