Body: <p>There are 2 types of ears in insects (see <a href="https://doi.org/10.1146/annurev-ento-010715-023631" rel="nofollow noreferrer">here</a>):</p>
  <ul>
  <li><strong>tympanal ears</strong> to detect the sound pressure (force exerted by air particles on a surface)</li>
  <li><strong>hairs/antennal ears</strong> to detect the air particle-velocity component of sound through air particle friction to free-standing hairs</li>
  </ul>
  <p>A spherical sound source creates 2 components (see this <a href="https://www.acs.psu.edu/drussell/demos/burns_phd_animations/burns_phd_anim.html" rel="nofollow noreferrer">animation</a>):</p>
  <ul>
  <li>a <strong>reactive</strong> one which is present locally only (~ 1 wave length far from the source); it does not create any pressure field and the particle-velocity <strong>attenuates with the inverse of distance square</strong> (ref: table 4 of <a href="https://doi.org/10.1098/rstb.1998.0219" rel="nofollow noreferrer">Bennet-Clark 1998</a>)</li>
  <li>an <strong>active</strong> one which propagates; both particle-velocity and pressure <strong>attenuates with the inverse of distance</strong> (ref: table 4 of <a href="https://doi.org/10.1098/rstb.1998.0219" rel="nofollow noreferrer">Bennet-Clark 1998</a>)</li>
  </ul>
  <p>I can understand why all species that use short-range communication have antennal ears because it is more efficient to detect particle-velocity when they are in the near-field where the particle-velocity level increases far more than the pressure level when getting close to the sound source (1/r^2 vs 1/r; see <a href="https://doi.org/10.1098/rstb.1998.0219" rel="nofollow noreferrer">table 4</a>)</p>
  <p>However, in terrestrial vertebrates and insects (e.g. crickets) that use long-range communication, they all have tympanal ears. I don't understand because both particle-velocity and pressure attenuates with 1/r, <strong>so why would it be more efficient to have tympanal ears to hear at long range</strong>?</p>
  
Tags: <particle-velocity><pressure><evolution>
Title: Tympanal versus antennal hearing: Why is tympanal hearing preferred for long-range?
ThreadText: # Tympanal versus antennal hearing: Why is tympanal hearing preferred for long-range?
  
  (Asked by: username_0 on 2022-07-01)
  
  There are 2 types of ears in insects (see [here](https://doi.org/10.1146/annurev-ento-010715-023631)):
  
  * **tympanal ears** to detect the sound pressure (force exerted by air particles on a surface)
  * **hairs/antennal ears** to detect the air particle-velocity component of sound through air particle friction to free-standing hairs
  
  A spherical sound source creates 2 components (see this [animation](https://www.acs.psu.edu/drussell/demos/burns_phd_animations/burns_phd_anim.html)):
  
  * a **reactive** one which is present locally only (~ 1 wave length far from the source); it does not create any pressure field and the particle-velocity **attenuates with the inverse of distance square** (ref: table 4 of [Bennet-Clark 1998](https://doi.org/10.1098/rstb.1998.0219))
  * an **active** one which propagates; both particle-velocity and pressure **attenuates with the inverse of distance** (ref: table 4 of [Bennet-Clark 1998](https://doi.org/10.1098/rstb.1998.0219))
  
  I can understand why all species that use short-range communication have antennal ears because it is more efficient to detect particle-velocity when they are in the near-field where the particle-velocity level increases far more than the pressure level when getting close to the sound source (1/r^2 vs 1/r; see [table 4](https://doi.org/10.1098/rstb.1998.0219))
  
  However, in terrestrial vertebrates and insects (e.g. crickets) that use long-range communication, they all have tympanal ears. I don't understand because both particle-velocity and pressure attenuates with 1/r, **so why would it be more efficient to have tympanal ears to hear at long range**?
  
  **Tags:** particle-velocity, pressure, evolution
  
  
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  ## 0 answers
  
  