01942nas a2200205   4500008004100000245008000041210006900121520124300190653001701433653001201450653002901462653002101491653001401512653002101526653001301547100001401560700002701574700001501601856012001616       2008                        eng d00aSexual dimorphism in auditory mechanics: tympanal vibrations of Cicada orni0 aSexual dimorphism in auditory mechanics tympanal vibrations of C3 a<p>In cicadas, the tympanum is anatomically intricate and employs complex vibrations as a mechanism for auditory frequency analysis. Using microscanning laser Doppler vibrometry, the tympanal mechanics of Cicada orni can be characterized in controlled acoustical conditions. The tympanum of C. orni moves following a simple drum-like motion, rather than the travelling wave found in a previous study of Cicadatra atra. There is a clear sexual dimorphism in the tympanal mechanics. The large male tympanum is unexpectedly insensitive to the dominant frequency of its own calling song, possibly a reflection of its dual purpose as a sound emitter and receiver. The small female tympanum appears to be mechanically sensitive to the dominant frequency of the male calling song and to high-frequency sound, a capacity never suspected before in these insects. This sexual dimorphism probably results from a set of selective pressures acting in divergent directions, which are linked to the different role of the sexes in sound reception and production. These discoveries serve to indicate that there is far more to be learnt about the development of the cicada ear, its biomechanics and evolution, and the cicada&#39;s acoustic behaviour.</p>
10abiomechanics10ahearing10ahigh-frequency reception10alaser vibrometry10apredation10aselective forces10atympanum1 aSueur, J.1 aWindmill, James, F. C.1 aRobert, D.  uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.018804https://syndication.highwire.org/content/doi/10.1242/jeb.01880401726nas 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<p>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.</p>
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.033019