QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online October 5, 2006
Journal of Experimental Biology 209, 4115-4128 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02460

This Article Summary Full Text Full Text (PDF) Supplementary Material Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sueur, J. Articles by Robert, D. Search for Related Content PubMed PubMed Citation Articles by Sueur, J. Articles by Robert, D.

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

Jérôme Sueur^1,*, James F. C. Windmill² and Daniel Robert²

¹ NAMC-CNRS UMR 8620, Bât. 446, Université Paris XI, 91405 Orsay Cedex, France
² School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK

View larger version (119K): [in a new window]   Fig. 1. Male Cicadatra atra emitting a calling song in a typical upside-down position. The white arrow on the male shows the localization of the auditory sensory organ. Scale=5 mm. Picture by Stéphane Puissant/OPIE-LR.

View larger version (100K): [in a new window]   Fig. 2. Posterior view of female left tympanum and male right tympanum with close-up on the ridge. The membrane and the ridge are shown on male tympanum, the red dots indicating the laser positions where frequency measurements were made. X and Y, respectively, indicate the apex and the base of the ridge. Scale=0.5 mm.

View larger version (44K): [in a new window]   Fig. 3. Calling song of Cicadatra atra. (A) Spectra of four distinct males (grey lines) and their mean (black line). (B) Oscillogram and spectrogram corresponding to the zone delimited by the vertical red lines on the bottom oscillogram. (C) Oscillogram showing successive calls. Red lines show the part of the song enlarged in B.

View larger version (38K): [in a new window]   Fig. 4. Deflection shapes of a female right tympanal membrane. TM was stimulated with a FM sweep signal. The oscillations are shown for four different driving frequencies (5, 10, 15, 20 kHz) at four different phases (0, 90, 180, 270°) along the oscillation cycle. For 10 kHz, the dominant frequency of male calling song, deflections are shown as profiles, as if looking at the tympanum from its side. Deflections are expressed as displacement gain following the colour scale. Red indicates outward tympanal deflections and green inward tympanal deflections. Note the difference in scale for each driving frequency. Orientation is indicated by a 3D space reference (D, dorsal; V, ventral; P, posterior; A, anterior; L, left; R, right). The horizontal black arrow indicates the direction of wave propagation. The ridge is visible as a black elongated teardrop (blue arrow) on the scan map.

View larger version (50K): [in a new window]   Fig. 5. Deflection shapes of a male left tympanal membrane. TM was stimulated with a FM sweep signal (0–30 kHz). The horizontal arrow indicates the direction of wave propagation. See Fig. 4 for details.

View larger version (55K): [in a new window]   Fig. 6. Deflection shapes of a male left tympanal ridge as revealed by high resolution scanning. Stimulation was done with a FM sweep stimulus. The horizontal arrow indicates the direction of wave propagation. See Fig. 4 for details.

View larger version (40K): [in a new window]   Fig. 7. Deflection shapes of a male left tympanal ridge and female right tympanal ridge. TM was stimulated with a natural male calling song. Deflections are shown for a 10 kHz frequency sine wave (calling song dominant frequency). Horizontal arrows indicate the direction of wave propagation. Note the difference in scale range between male and female. See Fig. 4 for details.

View larger version (42K): [in a new window]   Fig. 8. Phase response along the ridge (TR). The phase response shows an increasing lag with both frequency and distance along the ridge. The phase lag increases to –300° for females and to –900° for males. X=TR apex, Y=TR base (see Fig. 2).

View larger version (49K): [in a new window]   Fig. 9. Envelopes of mechanical deflections along the tympanal ridge. Top: for a 10 kHz driving frequency (calling song dominant frequency), deflections are shown for phase increments of 10° in the full oscillation cycle. Minimal and maximal values are plotted in red. Bottom: minimal and maximal deflection shapes for different driving frequencies: 5 kHz (black), 10 kHz (red), 15 kHz (green), 20 kHz (blue). Coloured dots indicate the position along the ridge where the deflection envelope is maximum for the frequency coding by colour. X, apex of the TR; Y, base of the TR.

View larger version (64K): [in a new window]   Fig. 10. Frequency response of the ridge when stimulated with a FM sweep stimulus. Frequency spectra of ridge resonance were computed at each point of a 35-point line scan from the apex of the ridge to its base. Spectra were then plotted successively on a density plot ranging from 0 to –50 dB.

View larger version (18K): [in a new window]   Fig. 11. Frequency of maximal mechanical response measured along the ridge, from apex to base, in response to FM sweep stimulus. Grey area corresponds to the frequency band containing 50% of calling song spectral energy. Values are means ± s.d. for 9 males (blue) and 6 females (red).

View larger version (21K): [in a new window]   Fig. 12. Travelling wave parameters of the ridge: (A) Phase difference, (B) travel time, (C) wave velocity, (D) wavelength. Values are means ± s.d. for 9 males and 6 females.

View larger version (17K): [in a new window]   Fig. 13. Oscillations of the tympanum ridge after the broadcast of an intense short click. Oscillations are shown for one female and one male at three positions along the ridge: apex, middle and base. Note the difference in amplitude and period of the oscillations.

View larger version (16K): [in a new window]   Fig. 14. Frequency response of the ridge from apex to base, stimulated with clicks. Grey area corresponds to 50% of calling song spectral energy. Values are means ± s.d. for 6 males (blue) and 3 females (red).

View larger version (18K): [in a new window]   Fig. 15. Response velocity of the tympanal membrane at 11.7 kHz as a function of a continuous increase in forcing. Sound pressure was linearly increased from 1 mPa to 30 mPa in the time span of 5 s. Black curve: vibration velocity measured on the ridge (between the apex and the base). Green curve: time profile of sound stimulus.