01453nas a2200121 4500008004100000245008400041210006900125520101100194100003201205700002001237700002101257856005301278 2014 eng d00aLateralization of Travelling Wave Response in the Hearing Organ of Bushcrickets0 aLateralization of Travelling Wave Response in the Hearing Organ 3 a

Travelling waves are the physical basis of frequency discrimination in many vertebrate and invertebrate taxa, including mammals, birds, and some insects. In bushcrickets (Tettigoniidae), the crista acustica is the hearing organ that has been shown to use sound-induced travelling waves. Up to now, data on mechanical characteristics of sound-induced travelling waves were only available along the longitudinal (proximal-distal) direction. In this study, we use laser Doppler vibrometry to investigate in-vivo radial (anterior-posterior) features of travelling waves in the tropical bushcricket Mecopoda elongata. Our results demonstrate that the maximum of sound-induced travelling wave amplitude response is always shifted towards the anterior part of the crista acustica. This lateralization of the travelling wave response induces a tilt in the motion of the crista acustica, which presumably optimizes sensory transduction by exerting a shear motion on the sensory cilia in this hearing organ.

1 aUdayashankar, Arun, Palghat1 aKössl, Manfred1 aNowotny, Manuela uhttps://dx.plos.org/10.1371/journal.pone.008609002049nas a2200121 4500008004100000245009000041210006900131520160100200100003201801700002001833700002101853856005301874 2012 eng d00aTonotopically Arranged Traveling Waves in the Miniature Hearing Organ of Bushcrickets0 aTonotopically Arranged Traveling Waves in the Miniature Hearing 3 a

Place based frequency discrimination (tonotopy) is a fundamental property of the coiled mammalian cochlea. Sound vibrations mechanically conducted to the hearing organ manifest themselves into slow moving waves that travel along the length of the organ, also referred to as traveling waves. These traveling waves form the basis of the tonotopic frequency representation in the inner ear of mammals. However, so far, due to the secure housing of the inner ear, these waves only could be measured partially over small accessible regions of the inner ear in a living animal. Here, we demonstrate the existence of tonotopically ordered traveling waves covering most of the length of a miniature hearing organ in the leg of bushcrickets in vivo using laser Doppler vibrometery. The organ is only 1 mm long and its geometry allowed us to investigate almost the entire length with a wide range of stimuli (6 to 60 kHz). The tonotopic location of the traveling wave peak was exponentially related to stimulus frequency. The traveling wave propagated along the hearing organ from the distal (high frequency) to the proximal (low frequency) part of the leg, which is opposite to the propagation direction of incoming sound waves. In addition, we observed a non-linear compression of the velocity response to varying sound pressure levels. The waves are based on the delicate micromechanics of cellular structures different to those of mammals. Hence place based frequency discrimination by traveling waves is a physical phenomenon that presumably evolved in mammals and bushcrickets independently.

1 aUdayashankar, Arun, Palghat1 aKössl, Manfred1 aNowotny, Manuela uhttps://dx.plos.org/10.1371/journal.pone.003100802311nas a2200181 4500008004100000245006200041210006200103520174300165653002101908653001301929653001901942100002101961700003201982700001902014700002102033700002002054856005502074 2011 eng d00aSound Transduction in the Auditory System of Bushcrickets0 aSound Transduction in the Auditory System of Bushcrickets3 a

Place based frequency representation, called tonotopy,is a typical property of hearing organs for the discrimination of different frequencies. Due to its coiled structure and secure housing, it is difficult access the mammalian cochlea. Hence, our knowledge about in vivo inner-ear mechanics is restricted to small regions. In this study, we present in vivo measurements that focus on the easily accessible, uncoiled auditory organs in bushcrickets, which are located in their foreleg tibiae. Sound enters the body via an opening at the lateral side of the thorax and passes through a horn-shaped acoustic trachea before reaching the high frequency hearing organ called crista acustica. In addition to the acoustic trachea as structure that transmits incoming sound towards the hearing organ, bushcrickets also possess two tympana, specialized plate-like structures, on the anterior and posterior side of each tibia. They provide a secondary path of excitation for the sensory receptors at low frequencies. We investigated the mechanics of the crista acustica in the tropical bushcricket Mecopoda elongata. The frequency-dependent motion of the crista acustica was captured using a laser-Doppler-vibrometer system. Using pure tone stimulation of the crista acustica, we could elicit traveling waves along the length of the hearing organ that move from the distal high frequency to the proximal low frequency region. In addition, distinct maxima in the velocity response of the crista acustica could be measured at ̃7 and ̃17 kHz. The travelling-wave-based tonotopy provides the basis for mechanical frequency discrimination along the crista acustica and opens up new possibility to investigate traveling wave mechanics in vivo.

10aLDV-measurements10atonotopy10atraveling wave1 aNowotny, Manuela1 aUdayashankar, Arun, Palghat1 aWeber, Melanie1 aHummel, Jennifer1 aKössl, Manfred uhttp://aip.scitation.org/doi/abs/10.1063/1.365813100620nas a2200181 4500008004100000245009100041210006900132653002300201653001900224653001200243653002700255100002100282700002100303700001900324700002000343700002000363856005500383 2010 eng d00aAcoustic-induced motion of the bushcricket (Mecopoda elongata, Tettigoniidae) tympanum0 aAcousticinduced motion of the bushcricket Mecopoda elongata Tett10aAcoustic resonance10ainsect hearing10atrachea10aVibration measurements1 aNowotny, Manuela1 aHummel, Jennifer1 aWeber, Melanie1 aMöckel, Doreen1 aKössl, Manfred uhttp://link.springer.com/10.1007/s00359-010-0577-602386nas a2200193 4500008004100000245009800041210006900139520176800208653001901976653001201995653002902007653002202036653001302058653001902071100001502090700001402105700001602119856005702135 2011 eng d00aSound-induced tympanal membrane motion in bushcrickets and its relationship to sensory output0 aSoundinduced tympanal membrane motion in bushcrickets and its re3 a

n the auditory system of bushcrickets, sound can reach the receptors via two different paths: (i) by acting on the outside of the tympana situated on both sides of each foreleg or (ii) through the acoustic trachea that opens at a spiracle on the thorax. While the spiracle is considered to be the main point of sound entry for higher audio and ultrasonic frequencies, the role of the tympana is still unclear. The tympana border the air-filled acoustic trachea as well as the fluid-filled haemolymph channel containing the receptor organs. To understand their role during sound transduction, the sound-induced neuronal response of the hearing organ was recorded in combination with measurement of tympanal membrane motion using laser-Doppler vibrometry. For far-field stimulation, the frequency of the most sensitive hearing (∼16 kHz) matched the frequency of a pronounced maximum of tympanal membrane vibration. A second maximum of tympanum motion at lower frequencies (∼7 kHz) was correlated with an increased nerve activity at higher intensities (>70 dB sound pressure level, SPL). These correlations support the hypothesis of functional coupling between tympanum motion and nerve activity. When sound stimuli were applied locally, through either the tympanum or the spiracle, significant differences between tympanum motion and nerve activity were found. These discrepancies show that tympanum motion and neuronal response are not coupled directly and that there is no linear relationship with the applied SPL. Taken together, these data verify a functional, albeit indirect, coupling of tympanum motion and sensory cell activity for one of the pronounced vibration maxima, which appears to represent a resonance frequency of the tympanum.

10ainsect hearing10akatydid10alaser-Doppler vibrometer10aMecopoda elongata10aspiracle10atympanal nerve1 aHummel, J.1 aKossl, M.1 aNowotny, M. uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.05444501600nas a2200193 4500008004100000245012200041210006900163300001200232490000600244520097200250653001001222653003101232653001501263653001501278653001801293100003001311700002401341856004101365 2017 eng d00aFirst record of subfamily Mecopodinae (Orthoptera: Tettigoniidae) from Bihar along with description of Indian species0 aFirst record of subfamily Mecopodinae Orthoptera Tettigoniidae f a803-8070 v53 aThe present study was based on the specimens of Mecopodinae during the course of a survey from (01/03/2015 to 30/03/2015) from various agricultural areas of different regions of Bihar. Four male specimens were collected from different localities and identified as a species Mecopoda elongata elongata (Linnaeus, 1758) (Orthoptera: Tettigoniidae), was newly recorded from Bihar, India. The description was based on both conventional morphological and genitalic characters. The identifying features of the species were body very large, brown in color, tibial tympana opened on both the sides, stridulatory file having 98 teeth arranged in lamelliform manner under the side of left tegmen, male subgenital plate developed conically from region of bifurcation with short styli and hind femur & tibiae very long and large. A morphological description, as well as detailed illustrations of this species is presented. Distribution and morphometrically data is also provided.10aIndia10aMecopoda elongata elongata10anew record10aOrthoptera10aTettigoniidae1 aFarooqi, Mohd, Kaleemulla1 aUsmani, Mohd, Kamil uhttps://bio.acousti.ca/ja/node/5146900559nas a2200133 4500008004100000245009200041210006900133260002000202300001100222490000600233100002700239700002100266856013800287 2015 eng d00aPosition-dependent hearing in three species of bushcrickets (Tettigoniidae, Orthoptera)0 aPositiondependent hearing in three species of bushcrickets Tetti cOct-26-20152016 a1404730 v21 aLakes-Harlan, Reinhard1 aScherberich, Jan uhttp://rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.140473https://syndication.highwire.org/content/doi/10.1098/rsos.140473