Fiddler on the Tree - A Bush-Cricket Species with Unusual Stridulatory Organs and Song
Insects of the order Orthoptera are well-known for their acoustic communication. The structures used for this purpose show a high diversity which obviously relates to differences in song parameters and to the physics of sound production. Here we describe song and morphology of the sound producing organs of a tropical bush-cricket, Ectomoptera nepicauda, from East Africa. It has a very unusual calling song consisting of frequency-modulated, pure-tone sounds in the high ultrasonic range of 80 to120 kHz and produced by extremely fast wing movements. Concerning morphology, it represents the most extreme state in the degree of left-right fore-wing differentiation found among Orthoptera: the acoustic parts of the left fore-wing consist exclusively of the stridulatory file, comparable in function to the bow of a violin, while the right wing carries only the plectrum ( =  string) and mirror ( =  soundbox).
Sound Production in Cyphoderris monstrosa (Orthoptera: Prophalangopsidae)
Cyphoderris monstrosa Uhler, one of only 2 species of Prophalangopsidae in the United States, produces intense short trills at about 13 kilohertz at 25°C. Pulse rate averages 71.4 per second and trill duration ranges from 0.5 to 2.0 second. Males switch wings regularly while calling, a phenomenon not typical in Gryllidae and Tettigoniidae.
Sex-specific spectral tuning for the partner's song in the duetting bushcricket Ancistrura nigrovittata (Orthoptera: Phaneropteridae)
The song of the male bushcricket Ancistrura nigrovittata consists of a sequence of verses. Each verse comprises a syllable group, plus, after about 400 ms a single syllable serving as a trigger for the female response song. The carrier frequency of the male song spectrum peaks at around 15 kHz, while the female song peaks at around 27 kHz. The thresholds of female responses to models of male songs are lowest for song frequencies between 12 and 16 kHz and therefore correspond to the male song spectrum. The threshold curve of the female response to the trigger syllable at different frequencies has the same shape as the tuning for the syllable group. Phonotactic thresholds of male Ancistrura nigrovittata to synthetic female responses at different frequencies are lowest between 24 and 28 kHz and thereby correspond to the female song spectrum and clearly differ from female response thresholds. Activity of the tympanic fibre bundle of both sexes is most sensitive between 15 and 35 kHz and therefore not specifically tuned to the partner's song. Individual behavioural thresholds have their minimum within 10 dB of the values of tympanic thresholds.