@article {51480, title = {Chamber music: an unusual Helmholtz resonator for song amplification in a Neotropical bush-cricket (Orthoptera, Tettigoniidae)}, journal = {The Journal of Experimental Biology}, volume = {220}, year = {2017}, month = {Sep-15-20172153}, pages = {2900 - 2907}, abstract = {

Animals use sound for communication, with high-amplitude signals being selected for attracting mates or deterring rivals. High amplitudes are attained by employing primary resonators in sound producing structures to amplify the signal (e.g., avian syrinx). Some species actively exploit acoustic properties of natural structures to enhance signal transmission by using these as secondary resonators (e.g., tree-hole frogs). Male bush-crickets produce sound by tegminal stridulation and often use specialised wing areas as primary resonators. Interestingly, Acanthacara acuta, a Neotropical bush-cricket, exhibits an unusual pronotal inflation, forming a chamber covering the wings. It has been suggested that such pronotal chambers enhance amplitude and tuning of the signal by constituting a (secondary) Helmholtz resonator. If true, the intact system \– when stimulated sympathetically with broadband sound \– should show clear resonance around the song carrier frequency which should be largely independent of pronotum material, and change when the system is destroyed. Using laser Doppler vibrometry on living and preserved specimens, micro computed tomography, 3D printed models, and finite element modelling, we show that the pronotal chamber not only functions as a Helmholtz resonator due to its intact morphology but also resonates at frequencies of the calling song on itself, making song production a three-resonator system.

}, keywords = {acoustic resonator, bioacoustics, bush-cricket, finite element modelling, laser Doppler vibrometry, micro computed tomography}, issn = {0022-0949}, doi = {10.1242/jeb.160234}, url = {http://jeb.biologists.org/lookup/doi/10.1242/jeb.160234}, author = {Jonsson, Thorin and Robson Brown, Kate and Sarria-S, Fabio A. and Walker, Matthew and Montealegre-Z, Fernando} } @article {47329, title = {Wing mechanics, vibrational and acoustic communication in a new bush-cricket species of the genus Copiphora (Orthoptera: Tettigoniidae) from Colombia}, journal = {Zoologischer Anzeiger - A Journal of Comparative Zoology}, volume = {263}, year = {2016}, month = {Jan-07-2016}, pages = {55 - 65}, 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 Copiphora 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. 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. The broadband calling song spectrum results from several wing resonances activated simultaneously during stridulation. Under laboratory conditions the calling song duty cycle is very low and males spend more time tremulating than singing.

}, keywords = {bioacoustics, biotremology, bush-cricket, laser Doppler vibrometer, resonance, tremulation, ultrasound}, issn = {00445231}, doi = {10.1016/j.jcz.2016.04.008}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0044523116300584}, author = {Sarria-S, Fabio A. and Buxton, Kallum and Jonsson, Thorin and Fernando Montealegre-Zapata} }