02436nas a2200229   4500008004100000022001400041245008800055210006900143260001600212300001600228490000800244520157900252653002701831653001901858653002701877653002901904653002001933653002301953100002501976700001902001856018602020       2016                        eng d  a0022-094900aFunctional relevance of acoustic tracheal design in directional hearing in crickets0 aFunctional relevance of acoustic tracheal design in directional   cMar-10-2017  a3294 - 33000 v2193 a<p>Internally coupled ears (ICEs) allow small animals to reliably determine the direction of a sound source. ICEs are found in a variety of taxa, but crickets have evolved the most complex arrangement of coupled ears: an acoustic tracheal system composed of a large cross-body trachea that connects two entry points for sound in the thorax with the leg trachea of both ears. The key structure that allows for the tuned directionality of the ear is a tracheal inflation (acoustic vesicle) in the midline of the cross-body trachea holding a thin membrane (septum). Crickets are known to display a wide variety of acoustic tracheal morphologies, most importantly with respect to the presence of a single or double acoustic vesicle. However, the functional relevance of this variation is still not known. In this study, we investigated the peripheral directionality of three co-occurring, closely related cricket species of the subfamily Gryllinae. No support could be found for the hypothesis that a double vesicle should be regarded as an evolutionary innovation to (1) increase interaural directional cues, (2) increase the selectivity of the directional filter or (3) provide a better match between directional and sensitivity tuning. Nonetheless, by manipulating the double acoustic vesicle in the rainforest cricket Paroecanthus podagrosus, selectively eliminating the sound-transmitting pathways, we revealed that these pathways contribute almost equally to the total amount of interaural intensity differences, emphasizing their functional relevance in the system.</p>
10aacoustic communication10ainsect hearing10aInternally coupled ear10alaser Doppler vibrometry10aMatched filters10aSound localization1 aSchmidt, Arne, K. D.1 aRömer, Heiner  uhttp://jeb.biologists.org/lookup/doi/10.1242/jeb.145524https://syndication.highwire.org/content/doi/10.1242/jeb.145524https://syndication.highwire.org/content/doi/10.1242/jeb.145524