01444nas a2200205 4500008004100000245006500041210006500106520072400171653002400895653002900919653001200948653002900960653001300989100001901002700002501021700002001046700002201066700001901088856013101107 2014 eng d00aEnergy localization and frequency analysis in the locust ear0 aEnergy localization and frequency analysis in the locust ear3 a

Animal ears are exquisitely adapted to capture sound energy and perform signal analysis. Studying the ear of the locust, we show how frequency signal analysis can be performed solely by using the structural features of the tympanum. Incident sound waves generate mechanical vibrational waves that travel across the tympanum. These waves shoal in a tsunami- like fashion, resulting in energy localization that focuses vibrations onto the mechanosensory neurons in a frequency-dependent manner. Using finite element analysis, we demonstrate that two mechanical properties of the locust tympanum, distributed thickness and tension, are necessary and sufficient to generate frequency-dependent energy localization.

10aenergy localization10afrequency discrimination10atension10atravelling flexural wave10atympanum1 aMalkin, Robert1 aMcDonagh, Thomas, R.1 aMhatre, Natasha1 aScott, Thomas, S.1 aRobert, Daniel uhttps://royalsocietypublishing.org/doi/10.1098/rsif.2013.0857https://royalsocietypublishing.org/doi/pdf/10.1098/rsif.2013.085701726nas a2200193 4500008004100000245008300041210006900124520106900193653001201262653001701274653001101291653002901302653001201331653001301343100002701356700001401383700001501397856012001412 2009 eng d00aThe next step in cicada audition: measuring pico-mechanics in the cicada's ear0 anext step in cicada audition measuring picomechanics in the cica3 a

Female cicadas use sound when they select a mate from a chorus of singing males. The cicada has a tympanal ear; and the tympanal membrane, and constituent tympanal ridge, act as both acousto-mechanical transducers and frequency filters. The tympanal ridge is physically connected to a large number of mechanoreceptor neurons via a cuticular extension known as the tympanal apodeme. Using microscanning laser Doppler vibrometry, we measured for the first time the in vivo vibrations of the apodeme of female Cicadatra atra in response to the motion of the tympanum driven by sound. These measurements reveal that the nanoscale motion of the tympanal membrane is over a magnitude greater than that of the apodeme. Furthermore, the apodeme acts as an additional mechanical frequency filter, enhancing that of the tympanal ridge, narrowing the frequency band of vibration at the mechanoreceptor neurons to that of the male calling song. This study enhances our understanding of the mechanical link between the external ear of the cicada and its sensory cells.

10aapodeme10abiomechanics10aCicada10afrequency discrimination10ahearing10atympanum1 aWindmill, James, F. C.1 aSueur, J.1 aRobert, D. uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.033019https://syndication.highwire.org/content/doi/10.1242/jeb.03301901885nas a2200193 4500008004100000245009700041210006900138520127800207653001701485653001101502653002901513653001201542653002001554653001301574100001801587700002601605700001901631856004101650 2006 eng d00aTuning the drum: the mechanical basis for frequency discrimination in a Mediterranean cicada0 aTuning the drum the mechanical basis for frequency discriminatio3 a

Cicadas are known to use sound to find a mate. While the mechanism employed by male cicadas to generate loud calling songs has been described in detail, little information exists to explain how their ears work. Using microscanning laser Doppler vibrometry, the tympanal vibrations in the cicada Cicadatra atra are measured in response to acoustic playbacks. The topographically accurate optical measurements reveal the vibrational behaviour of the anatomically complex tympanal membrane. Notably, the tympanal ridge, a distinct structural element of the tympanum that is a link to the receptor cells, undergoes mechanical vibrations reminiscent of a travelling wave. In effect, the frequency for which the maximum deflection amplitude is observed regularly decreases from the apex to the base of the ridge. It is also shown that whilst female ears are mechanically tuned to the male's song, the male's tympanum is only partially tuned to its own song. This study establishes the presence of a peripheral auditory mechanism that can potentially process auditory frequency analysis. In view of the importance of acoustic signalling in cicadas, this unconventional tympanal mechanism may be employed in the context of species recognition and sexual selection.

10abiomechanics10aCicada10afrequency discrimination10ahearing10atravelling wave10atympanum1 aSueur, Jerome1 aWindmill, James, F.C.1 aRobert, Daniel uhttps://bio.acousti.ca/uk/node/57622