Abstract

Male bush-crickets produce acoustic signals by wing stridulation to call females. Several species also alternate vibratory signals with acoustic calls for intraspecific communication, a way to reduce risk of detection by eavesdropping predators. Both modes of communication have been documented mostly in neotropical species, for example in the genus Copiphora. In this article, we studied vibratory and acoustic signals and the biophysics of wing resonance in C. vigorosa, a new species from the rainforest of Colombia. Different from other Copiphora species in which the acoustic signals have been properly documented as pure tones, C. vigorosa males produce a complex modulated broadband call peaking at ca. 30 kHz. Such a broadband spectrum results from several wing resonances activated simultaneously during stridulation. Since males of this species do rarely sing, we also report that substratum vibrations have been adopted in this species as a persistent communication channel. Wing resonances and substratum vibrations were measured using a μ-scanning Laser Doppler Vibrometry. We found that the stridulatory areas of both wings exhibit a relatively broad-frequency response and the combined vibration outputs fits with the calling song spectrum breadth. Under laboratory conditions the calling song duty cycle is very low and males spend more time tremulating than singing.