Tuning the drum: the mechanical basis for frequency discrimination in a Mediterranean cicada

Jerome Sueur, J.F.C. Windmill, Daniel Robert

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Cicadas are known to use sound to find a mate. While the mechanism employed by male cicadas to generate loud calling songs has been described in detail, little information exists to explain how their ears work. Using microscanning laser Doppler vibrometry, the tympanal vibrations in the cicada Cicadatra atra are measured in response to acoustic playbacks. The topographically accurate optical measurements reveal the vibrational behaviour of the anatomically complex tympanal membrane. Notably, the tympanal ridge, a distinct structural element of the tympanum that is a link to the receptor cells, undergoes mechanical vibrations reminiscent of a travelling wave. In effect, the frequency for which the maximum deflection amplitude is observed regularly decreases from the apex to the base of the ridge. It is also shown that whilst female ears are mechanically tuned to the male's song, the male's tympanum is only partially tuned to its own song. This study establishes the presence of a peripheral auditory mechanism that can potentially process auditory frequency analysis. In view of the importance of acoustic signalling in cicadas, this unconventional tympanal mechanism may be employed in the context of species recognition and sexual selection.
Original languageEnglish
Pages (from-to)4115-4128
Number of pages14
JournalJournal of Experimental Biology
Volume209
DOIs
Publication statusPublished - 2006

Keywords

  • biomechanics
  • hearing
  • tympanum
  • travelling wave
  • frequency discrimination
  • cicada

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