On the tympanic membrane impedance of the katydid Copiphora gorgonensis (Insecta: Orthoptera: Tettigoniidae)

Celiker, Emine, Montealegre-Z, Fernando and Jonsson, Thorin (2020) On the tympanic membrane impedance of the katydid Copiphora gorgonensis (Insecta: Orthoptera: Tettigoniidae). The Journal of the Acoustical Society of America, 148 (4). pp. 1952-1960. ISSN 0001-4966

Full content URL: https://doi.org/10.1121/10.0002119

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On the tympanic membrane impedance of the katydid Copiphora gorgonensis (Insecta: Orthoptera: Tettigoniidae)
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Abstract

Katydids (bush-crickets) are endowed with tympanal ears located in their forelegs' tibiae. The tympana are backed by an air-filled tube, the acoustic trachea, which transfers the sound stimulus from a spiracular opening on the thorax to the internal side of the tympanic membranes (TM). In katydids the sound stimulus reaches both the external and internal side of the membranes, and the tympanal vibrations are then transferred to the hearing organ crista acoustica (CA) that contains the fluid-immersed mechanoreceptors. Hence the tympana are principally involved in transmitting and converting airborne sound into fluid vibrations that stimulate the auditory sensilla. Consequently, what is the transmission power to the CA? Are the TM tuned to a certain frequency? To investigate this, the surface normal acoustic impedance of the TM is calculated using finite-element analysis in the katydid Copiphora gorgonensis. From this, the reflectance and transmittance is obtained at the TM. Based on the results obtained in the frequency range 5-40 kHz, it is concluded that the tympana have considerably higher transmission around 23 kHz, corresponding to the dominant frequency of the male pure-tone calling song in this species.

Keywords:tympanic membrane, acoustic impedance, katydid hearing, finite element analysis
Subjects:F Physical Sciences > F380 Acoustics
C Biological Sciences > C100 Biology
Divisions:College of Science > School of Life Sciences
ID Code:42636
Deposited On:02 Nov 2020 13:03

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