@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 = {<p>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 \&ndash; when stimulated sympathetically with broadband sound \&ndash; 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.</p>
},
	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 {51479,
	title = {Covert stridulation: Novel sound generation by a South American Katydid},
	journal = {Naturwissenschaften},
	volume = {82},
	year = {1995},
	month = {Jan-02-1995},
	pages = {96 - 98},
	issn = {0028-1042},
	doi = {10.1007/BF01140151},
	url = {http://link.springer.com/10.1007/BF01140151},
	author = {Glenn K. Morris and Mason, A. C.}
}
@article {50909,
	title = {Morphological determinants of carrier frequency signal in katydids (Orthoptera): a comparative analysis using biophysical evidence},
	journal = {Journal of Evolutionary Biology},
	year = {2017},
	month = {Apr-09-2018},
	abstract = {<p>Male katydids produce mating calls by stridulation using specialized structures on the forewings. The right wing (RW) bears a scraper connected to a drum-like cell known as the mirror and a left wing (LW) that overlaps the RW and bears a serrated vein on the ventral side, the stridulatory file. Sound is generated with the scraper sweeping across the file, producing vibrations that are amplified by the mirror. Using this sound generator, katydids exploit a range of song carrier frequencies (CF) unsurpassed by any other insect group, with species singing as low as 600 Hz and others as high as 150 kHz. Sound generator size has been shown to scale negatively with CF, but such observations derive from studies based on few species, without phylogenetic control, and/or using only the RW mirror length. We carried out a phylogenetic comparative analysis involving 94 species of katydids to study the relationship between LW and RW components of the sound generator and the CF of the male\&$\#$39;s mating call, while taking into account body size and phylogenetic relationships. The results showed that CF negatively scaled with all morphological measures, but was most strongly related to components of the sound generation system (file, LW and RW mirrors). Interestingly, the LW mirror (reduced and non-functional) predicted CF more accurately than the RW mirror, and body size is not a reliable CF predictor. Mathematical models were verified on known species for predicting CF in species for which sound is unknown (e.g. fossils or museum specimens).</p>
},
	doi = {10.1111/jeb.13179},
	url = {http://doi.wiley.com/10.1111/jeb.13179},
	author = {Fernando Montealegre-Zapata and Ogden, Jessica and Jonsson, Thorin and Soulsbury, Carl D.}
}
