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

First published online July 14, 2008
Journal of Experimental Biology 211, 2379-2387 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.018804

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. Social Bookmarking                         What's this?

Sexual dimorphism in auditory mechanics: tympanal vibrations of Cicada orni

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

¹ Muséum National d'Histoire naturelle, Département Systématique et Evolution, UMR 5202 CNRS & USM 601 MNHN, 75005 Paris, France
² School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK

View larger version (77K): [in this window] [in a new window]   Fig. 1. Anterior and posterior (after removing the abdomen) views of male and female C. orni right tympanal membrane (TM). The male TM consists of three distinct parts, two of them are outlined with blue and green lines, respectively, and the third part is the area between. Female TM can be divided in two parts, one of them being shown in red. For both male and female the ridge area is indicated with a yellow dotted line. The shape of these parts differs slightly between anterior and posterior views as access and angle of view to the surface of the TM also differ. Scale bars, 0.5 mm.

View larger version (43K): [in this window] [in a new window]   Fig. 2. Frequency magnitude spectra of the male calling song, and of the TM vibrations of both sexes. (A) Calling song spectra of 10 distinct males (grey lines) and their mean (black line), 50% of the male calling song energy is highlighted with a light grey shading. (B) TM vibrations spectra of 11 males and seven females (thin lines) and their respective mean (bold lines) at low frequencies (1–22.05 kHz), vertical dotted lines show the correspondence between maximal TM resonance and male calling song spectra. (C) TM vibrations spectra of six males and eight females and their respective mean (bold lines) at high frequencies (20–80 kHz). Originally expressed as amplitude data (mV for recorded songs) or gain data (nm Pa–1 for TM vibrations), spectra were normalized between 0 and 1 and then transformed in decibels (dB) for the purpose of comparison.

View larger version (63K): [in this window] [in a new window]   Fig. 3. Deflection shapes of a male right TM and of a female left TM. The TM was stimulated with a FM sweep signal. (A) Oscillations are shown at eight different phases (45° increment) along the oscillation cycle at the best resonance frequency in the low frequency domain (2.075 kHz for the male, 4.1 kHz for the female) and at 50 kHz. Deflections are expressed as displacement gain following the colour scale (nm Pa–1). Red indicates outward tympanal deflections and green inward tympanal deflections. Note the difference in scale for each sex, and each driving frequency. Orientation is indicated by a 3D space reference (P, post; A, ant). The yellow line indicates the approximate position of the ridge and the green, blue and red lines show the limits of the different TM parts (see Fig. 1). (B) Corresponding envelopes of mechanical deflections (nm Pa–1) across TM along the W–Z transect line. The position of the ridge apex is indicated by a vertical yellow line. Green and red curves are minimum and maximum values, respectively. Note the difference in scale.

View larger version (43K): [in this window] [in a new window]   Fig. 4. Frequency response of the female tympanal ridge (TR). A line of scan points was taken along the ridge, and the frequency response was measured at each point. (A) A typical frequency response of the TR at its apex (red) and at its base (blue). Both frequency spectra show two main bands, one around 6 kHz, one around 17 kHz. Grey shading highlights 50% of the male calling song energy to show the match with the lowest frequency peak. Spectra were normalized between 0 and 1 to allow profile comparison. (B) Frequency of the two main spectra peaks. Filled circle indicate the lowest frequency peak and open circles, the highest peak. Different colours indicate different females. The number of scan points was not the same for all females. Grey area as in A. (C) Variation of the relative amplitude of both peaks on a linear scale normalized between 0 and 1. The relative amplitude of 17 kHz peak is linear and maximal whereas the relative amplitude of the 6 kHz peak increases along the ridge.

View larger version (37K): [in this window] [in a new window]   Fig. 5. Deflection shapes along the female TR from its apex to its base. The ridge was driven at its best resonance frequency in the low frequency domain (4.1 kHz) and at 50 kHz for the high frequency domain. Green and red curves are minimum and maximum values, respectively.

View larger version (24K): [in this window] [in a new window]   Fig. 6. Phase response of the female TR. (A) Phase response along the ridge from its apex to its base. (B) Difference between the phase response measured at the apex and at the base. There is no significant increasing phase lag with frequency, the maximal difference being 74° at 8.225 kHz. For comparison similar data measured for a Cicadatra atra female are shown, where travelling waves occur along the ridge. In this case the phase lag reaches 204° at 19.912 kHz. C. atra data are modified from Sueur et al. (Sueur et al., 2006).

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

Twitter