@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 {51475, title = {Wing resonances in a new dead-leaf-mimic katydid (Tettigoniidae: Pterochrozinae) from the Andean cloud forests}, journal = {Zoologischer Anzeiger - A Journal of Comparative Zoology}, volume = {270}, year = {2017}, month = {Jan-09-2017}, pages = {60 - 70}, abstract = {

Day-camouflaged leaf-mimic katydids Typophyllum spp. have a remarkable way of evading predators as male and female forewings appear as bite-damaged leaves complete with necrotic spots. As in all other katydids, males produce sound signals to attract females by rubbing their forewings together. The biophysical properties of these special leaf-like forewings remain obscure. Here we study the wing mechanics and resonances of Typophyllum spurioculis, a new species of leaf-mimic katydid with a broad distribution in the Andes from Western Ecuador to the middle Central Cordillera in Colombia. This species performs an unusual laterally directed aposematic display, showing orange spots that simulate eyes at the leg base. At night, males are conspicuous by their loud, audible calling songs, which exhibit two spectral peaks at ca. 7 and 12 kHz. Using micro-scanning laser Doppler vibrometry we find the effective sound radiators of the wings (speculae) vibrate with three modes of vibration, two of which include the frequencies observed in the calling song. Remarkably, this resonance is preserved in the parts of the wings mimicking necrotic leaves, which are in theory not specialised for sound production. The eyespot function is discussed.

}, keywords = {bush-cricket, katydid, mimetism, resonance, stridulation}, issn = {00445231}, doi = {10.1016/j.jcz.2017.10.001}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0044523117300748}, author = {Baker, Andrew and Sarria-S, Fabio A. and Glenn K. Morris and Jonsson, Thorin and Montealegre-Z, Fernando} } @article {50916, title = {Quality calls: phylogeny and biogeography of a new genus of neotropical katydid (Orthoptera: Tettigoniidae) with ultra pure-tone ultrasonics}, journal = {Systematics and Biodiversity}, volume = {9}, year = {2011}, month = {Sep-03-2012}, pages = {77 - 94}, abstract = {

This paper describes Artiotonus, a new genus of tropical katydid from Colombia and Ecuador. These acoustic ensiferans are represented by three species with a geographic distribution generally restricted to the rainforest of the Bolivar geosyncline of northwestern South America (Pacific). A phylogenetic analysis based on 28 morphological and six behavioural characters produced a tree (A. artius, (A. tinae, A. captivus)) with a consistency index of 0.9. All species are defined by a few autapomorphic changes. The most reliable character for identification is the temporal pattern of the calling song, suggesting a recent genetic divergence. Biogeographic analysis indicates that such genetic divergence began with geographic isolation produced before the Holocene transgression. Species of this genus are remarkable in that the calling song of males exhibits a narrow spectrum with a high quality factor (37\–42), unusual values for such ultrasonic signals. A broad discussion on the evolution of tonal calls and pulse trains is offered.

}, keywords = {Biogeography, calling song, Conocephalinae, high-Q, pure tone, ultrasound}, issn = {1477-2000}, doi = {10.1080/14772000.2011.560209}, url = {http://www.tandfonline.com/doi/abs/10.1080/14772000.2011.560209}, author = {Fernando Montealegre-Zapata and Glenn K. Morris and Sarria-S, Fabio A. and Mason, Andrew C.} } @article {47624, title = {Non-invasive biophysical measurement of travelling waves in the insect inner ear}, journal = {Royal Society Open Science}, volume = {4}, year = {2017}, month = {Jul-18-2017}, pages = {170-171}, abstract = {

Frequency analysis in the mammalian cochlea depends on the propagation of frequency information in the form of a travelling wave (TW) across tonotopically arranged auditory sensilla. TWs have been directly observed in the basilar papilla of birds and the ears of bush-crickets (Insecta: Orthoptera) and have also been indirectly inferred in the hearing organs of some reptiles and frogs. Existing experimental approaches to measure TW function in tetrapods and bush-crickets are inherently invasive, compromising the fine-scale mechanics of each system. Located in the forelegs, the bush-cricket ear exhibits outer, middle and inner components; the inner ear containing tonotopically arranged auditory sensilla within a fluid-filled cavity, and externally protected by the leg cuticle. Here, we report bush-crickets with transparent ear cuticles as potential model species for direct, non-invasive measuring of TWs and tonotopy. Using laser Doppler vibrometry and spectroscopy, we show that increased transmittance of light through the ear cuticle allows for effective non-invasive measurements of TWs and frequency mapping. More transparent cuticles allow several properties of TWs to be precisely recovered and measured in vivo from intact specimens. Our approach provides an innovative, non-invasive alternative to measure the natural motion of the sensilla-bearing surface embedded in the intact inner ear fluid.

}, doi = {10.1098/rsos.170171}, url = {http://rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.170171https://syndication.highwire.org/content/doi/10.1098/rsos.170171}, author = {Sarria-S, Fabio A. and Soulsbury, Carl D. and Fernando Montealegre-Zapata} } @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} } @article {20919, title = {Functional morphology of tegmina-based stridulation in the relict species Cyphoderris monstrosa (Orthoptera: Ensifera: Prophalangopsidae)}, journal = {The Journal of Experimental Biology}, volume = {220}, year = {2017}, month = {Dec-28-20172143}, pages = {1112 - 1121}, abstract = {

Male grigs, bush crickets and crickets produce mating calls by tegminal stridulation: the scraping together of modified forewings functioning as sound generators. Bush crickets (Tettigoniidae) and crickets (Gryllinae) diverged some 240 million years ago, with each lineage developing unique characteristics in wing morphology and the associated mechanics of stridulation. The grigs (Prophalangopsidae), a relict lineage more closely related to bush crickets than to crickets, are believed to retain plesiomorphic features of wing morphology. The wing cells widely involved in sound production, such as the harp and mirror, are comparatively small, poorly delimited and/or partially filled with cross-veins. Such morphology is similarly observed in the earliest stridulating ensiferans, for which stridulatory mechanics remains poorly understood. The grigs, therefore, are of major importance to investigate the early evolutionary stages of tegminal stridulation, a critical innovation in the evolution of the Orthoptera. The aim of this study is to appreciate the degree of specialization on grig forewings, through identification of sound radiating areas and their properties. For well-grounded comparisons, homologies in wing venation (and associated areas) of grigs and bush crickets are re-evaluated. Then, using direct evidence, this study confirms the mirror cell, in association with two other areas (termed \‘neck\’ and \‘pre-mirror\’), as the acoustic resonator in the grig Cyphoderris monstrosa. Despite the use of largely symmetrical resonators, as found in field crickets, analogous features of stridulatory mechanics are observed between C. monstrosa and bush crickets. Both morphology and function in grigs represents transitional stages between unspecialized forewings and derived conditions observed in modern species.

}, issn = {0022-0949}, doi = {10.1242/jeb.153106}, url = {http://jeb.biologists.org/lookup/doi/10.1242/jeb.153106https://syndication.highwire.org/content/doi/10.1242/jeb.153106}, author = {B{\'e}thoux, Olivier and Sarria-S, Fabio A. and Jonsson, Thorin and Mason, Andrew C. and Fernando Montealegre-Zapata} } @article {12664, title = {Shrinking Wings for Ultrasonic Pitch Production: Hyperintense Ultra-Short-Wavelength Calls in a New Genus of Neotropical Katydids (Orthoptera: Tettigoniidae)}, journal = {PLoS ONE}, volume = {9}, year = {2014}, month = {May-06-2014}, pages = {e98708}, abstract = {

This article reports the discovery of a new genus and three species of predaceous katydid (Insecta: Orthoptera) from Colombia and Ecuador in which males produce the highest frequency ultrasonic calling songs so far recorded from an arthropod. Male katydids sing by rubbing their wings together to attract distant females. Their song frequencies usually range from audio (5 kHz) to low ultrasonic (30 kHz). However, males of Supersonus spp. call females at 115 kHz, 125 kHz, and 150 kHz. Exceeding the human hearing range (50 Hz\–20 kHz) by an order of magnitude, these insects also emit their ultrasound at unusually elevated sound pressure levels (SPL). In all three species these calls exceed 110 dB SPL rms re 20 m Pa (at 15 cm). Males of Supersonus spp. have unusually reduced forewings (,0.5 mm 2 ). Only the right wing radiates appreciable sound, the left bears the file and does not show a particular resonance. In contrast to most katydids, males of Supersonus spp. position and move their wings during sound production so that the concave aspect of the right wing, underlain by the insect dorsum, forms a contained cavity with sharp resonance. The observed high SPL at extreme carrier frequencies can be explained by wing anatomy, a resonant cavity with a membrane, and cuticle deformation.

}, doi = {10.1371/journal.pone.0098708}, url = {http://dx.plos.org/10.1371/journal.pone.0098708}, author = {Sarria-S, Fabio A. and Glenn K. Morris and James F.C. Windmill and Joseph Curt Jackson and Fernando Montealegre-Zapata}, editor = {Etges, William J.} }