Previous in-vivo studies have shown that the tonotopically-organized hearing organ, the crista acustica, of the bushcricket Mecopoda elongata is a promising model for investigations of basic hearing mechanics. This linearly arranged organ with a length of <1 mm consists of about 45 receptor units and processes frequencies from about 4 up to at least 80 kHz. Pure-tone stimulation of the crista acustica leads to travelling waves along the longitudinal axis of the hearing organ. We found that the amplitude maximum of the sound-induced travelling waves is shifted in the radial direction during the propagation of the travelling wave. The overall amplitude maximum was found to be located always on one side (anterior) in respect to the transduction place. This mechanical biasing presumably optimizes the signal transduction. Additionally, the amplitude response maximum of the travelling wave during one cycle of motion exhibits different degrees in the radial shift. During broad-band noise stimulation, the mechanical response of the crista acustica exhibits a low-frequency dominance. When using the conspecific chirp of M. elongata (2-90 kHz), as stimulus frequencies above 30 kHz do not lead to large responses even though the hearing organ is able to detect frequencies up to at least 80 kHz, covering the frequency range of the chirp with its amplitude maximum at about 70 kHz. [ABSTRACT FROM AUTHOR]