The acoustic communication system in six species of armoured ground crickets (Orthoptera: Tettigoniidae: Hetrodinae): Commonalities and species-specific differences

The taxon Hetrodinae includes species of highly diverse morphology. Here, the acoustic communication system of six species is investigated. Males of Acanthoplus discoidales, Acanthoplus longipes, Acanthoproctus cervinus, Acanthoproctus diadematus, Enyaliopsis sp. and Spalacomimus liberiana produce long lasting calling songs to attract females. The frequency spectra of these songs are rather similar, while the temporal pattern differs largely. A continuous song, which is a train of verses, is produced by two species, while the other investigated Hetrodinae produce a song with periodical interruptions, which separates the verses into groups. The songs contain species specific numbers of impulses per verse or of verses per group. The stridulatory files have a different number of stridulatory teeth. Investigations of the neuronal system showed similarities in the central projections of the auditory fibres, while the number of sensory cells varies between the species. The greatest sensitivity of the hearing range is between 4 and 12 kHz, with a broader range in Acanthoproctus. In conclusion, the auditory communication system of the Hetrodinae species is similar to that of other Tettigoniids and exhibits species specific characters.