02345nas a2200265 4500008004100000022001400041245013100055210006900186260002000255300001600275490000800291520145900299653002301758653001701781653001701798653002901815653002901844653003001873100002001903700002401923700002401947700002001971700002801991856006002019 2017 eng d a0022-094900aChamber music: an unusual Helmholtz resonator for song amplification in a Neotropical bush-cricket (Orthoptera, Tettigoniidae)0 aChamber music an unusual Helmholtz resonator for song amplificat cSep-15-20172153 a2900 - 29070 v2203 a

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.

10aacoustic resonator10abioacoustics10abush-cricket10afinite element modelling10alaser Doppler vibrometry10amicro computed tomography1 aJonsson, Thorin1 aBrown, Kate, Robson1 aSarria-S, Fabio, A.1 aWalker, Matthew1 aMontealegre-Z, Fernando uhttp://jeb.biologists.org/lookup/doi/10.1242/jeb.16023402038nas a2200253 4500008004100000022001300041245011500054210006900169260001600238300001200254490000800266520125900274653001701533653001201550653001301562653001401575653001701589100001801606700002401624700002201648700002001670700002801690856006601718 2017 eng d a0044523100aWing resonances in a new dead-leaf-mimic katydid (Tettigoniidae: Pterochrozinae) from the Andean cloud forests0 aWing resonances in a new deadleafmimic katydid Tettigoniidae Pte cJan-09-2017 a60 - 700 v2703 a

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.

10abush-cricket10akatydid10amimetism10aresonance10astridulation1 aBaker, Andrew1 aSarria-S, Fabio, A.1 aMorris, Glenn, K.1 aJonsson, Thorin1 aMontealegre-Z, Fernando uhttp://linkinghub.elsevier.com/retrieve/pii/S004452311730074802036nas a2200157 4500008004100000245008500041210006900126260001600195300001200211490000600223520143000229100002401659700002401683700003301707856013801740 2017 eng d00aNon-invasive biophysical measurement of travelling waves in the insect inner ear0 aNoninvasive biophysical measurement of travelling waves in the i cJul-18-2017 a170-1710 v43 a

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.

1 aSarria-S, Fabio, A.1 aSoulsbury, Carl, D.1 aMontealegre-Zapata, Fernando uhttp://rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.170171https://syndication.highwire.org/content/doi/10.1098/rsos.17017102623nas a2200193 4500008004100000022001400041245014900055210006900204260002000273300001600293490000800309520186800317100002202185700002402207700002002231700002202251700003302273856012302306 2017 eng d a0022-094900aFunctional morphology of tegmina-based stridulation in the relict species Cyphoderris monstrosa (Orthoptera: Ensifera: Prophalangopsidae)0 aFunctional morphology of tegminabased stridulation in the relict cDec-28-20172143 a1112 - 11210 v2203 a

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.

1 aBĂ©thoux, Olivier1 aSarria-S, Fabio, A.1 aJonsson, Thorin1 aMason, Andrew, C.1 aMontealegre-Zapata, Fernando uhttp://jeb.biologists.org/lookup/doi/10.1242/jeb.153106https://syndication.highwire.org/content/doi/10.1242/jeb.153106