Ruspolia nitidula

The calling son, produced almost entirely at night, is a long, continuous buzz, often lasting for 10 minutes or more without pause. Oscillographic analysis shows that it consists of a uniform sequence of syllables repeated at the rate of about 70-100/s. The sound is often produced entirely by the closing strokes of the fore wings, but there are sometimes quieter opening hemisyllables; the closing hemisyllables usually last about 5-7 ms. The song is resonant, the audible sound produced being an almost pure tone of about 13-20 kHz (see Figs 186, 187). The frequency usually becomes lover during the course of each hemisyllable, beginning at about 15-20 kHz and ending at about 13-16 kHz.

Bellmann (1985a) describes (p. 90) and illustartes (p. 67) squeaking ('quietschende') sounds occurring at intervals during the song, and these can be heard in his cassette recording (Bellmann, 1985b). Such sounds do not, however, occur in any of our recordings.

The song of this species is superficially similar to those of Metrioptera roeselii and Gampsocleis glabra, which also produce prolonged buzzes, However, the songs of these two species are non-resonant, comprising a broad band of frequencies, and confusion is in any case unlikely in the field as they sing mainly during the daytime.

Males occassionally produce short echemes lasting only a second or two, but this is almost always in reaction to other males or some other disturbance and cannot be regarded as a normal part of the calling song. [1]
 

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