Melanie Weber
Doctoral student

Research project Active hearing in the bushcricket Mecopoda elongata

The tympanal hearing organs of insects emit distortion-product otoacoustic emissions (DPOAEs) whose characteristics are similar to those measured in vertebrates. In vertebrates such emissions provide evidence of nonlinearities in the cochlear mechanics and of active sound amplification. In contrast to vertebrates, the exact cellular origin of DPOAEs in insects is still unknown.

In my doctoral thesis I use the ear of the bushcricket Mecopoda elongata as an experimental model to answer the following questions: Do the sensory cells of the tympanal organ (or its accessory structures) act as active force amplifiers? And do such activities generate the DPOAEs? To detect the cellular elements (such as tubulin, myosin, prestin) which may potentially be involved in DPOAE generation, I apply immunohistochemical, histological, and biomolecular techniques.

In collaboration with Doreen Moeckel, we test whether the DPOAEs depend on intrinsic properties of the tympanal sensilla. Hence we evoke and record DPOAEs while manipulating the sensory cells of the tympanal organ mechanically or with pharmacological substances

Fig 1 (a) Adult female of the tropical bushcricket M. elongata raised in our laboratory. The auditory organ is situated in the tibia of each foreleg (arrow). (b) The sensory neurons (sn) are linearly arranged next to the tympanum (tym) while the cap cells (cc) are arranged above the auditory trachea.

Support by a stipend from the Jürgen Manchot Foundation.

Further readings

Weber M (2004): Untersuchungen über neuroaktive Substanzen in tympanalen Hörorganen der Laubheuschrecke Mecopoda elongata. Diplomarbeit, Fachbereich Biologie und Informatik, J.W. Goethe-Universität, Frankfurt a. M. pp81.

Publications

Nowotny, M. ; Möckel, D. ; Weber, M. ; Kössl, M. (2009):
Sound induced vibration pattern on the tympanal membranes of the bushcricket Mecopoda elongata.
8th Göttingen Meeting of the German Neuroscience Society: T17-1C.

Kössl, M. ; Möckel, D. ; Weber, M. ; Seyfarth, E.-A. (2008):
Otoacoustic emissions from insect ears: evidence of active hearing?
J Comp Physiol A 194: 597-609.

Kössl, M.; Möckel, D.; Weber, M.; Seyfarth, E.-A. (2008):
Schallemissionen aus Insektenohren: Hinweis auf aktives Hören?
Neuroforum 08 (1): 166-173.

Weber, M. ; Baumgarten, D. ; Winter; H. ; Kössl, M. ; Seyfarth, E.-A. (2006):
Active hearing in the bushcricket, Mecopoda elongata.
FENS Abstr 3: A 038.24.

Weber, M. ; Kössl, M. ; Volknandt, W. ; Seyfarth, E.-A. (2005)
Acetylcholine is a transmitter candidate in sensory neurons of the bushcricket ear (Mecopoda elongata).
Neuroforum 05, (9 Suppl): 94 A.