Acoustic Communication

<html> <head><script type="text/javascript" src="https://web-static.archive.org/_static/js/bundle-playback.js?v=msCHzjBE" charset="utf-8"></script> <script type="text/javascript" src="https://web-static.archive.org/_static/js/wombat.js?v=txqj7nKC" charset="utf-8"></script> <script>window.RufflePlayer=window.RufflePlayer||{};window.RufflePlayer.config={"autoplay":"on","unmuteOverlay":"hidden"};</script> <script type="text/javascript" src="https://web-static.archive.org/_static/js/ruffle/ruffle.js"></script> <script type="text/javascript"> __wm.init("https://web.archive.org/web"); __wm.wombat("http://www.cals.ncsu.edu/course/ent425/tutorial/Communication/sound.html","20110720011820","https://web.archive.org/","web","https://web-static.archive.org/_static/", "1311124700"); </script> <link rel="stylesheet" type="text/css" href="https://web-static.archive.org/_static/css/banner-styles.css?v=p7PEIJWi" /> <link rel="stylesheet" type="text/css" 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size="5" face="Arial, Helvetica, sans-serif"> <center> <b>General Entomology<br>ENT 425</b> </center> </td> <td width="33%" align="right"><br> <form action="/web/20110720011820/http://www.cals.ncsu.edu/course/ent425/tutorial/cgi-bin/redirect.pl" method="POST" onsubmit="return dropdown(this.gourl)"> <select name="gourl"> <option value="">Choose a Destination... <option value="../../index.html">      HomePage      </option> <option value="../../weekly.html">      Weekly Schedule      </option> <option value="../../syllab1.html">      Course Syllabus      </option> <option value="../../people.html">      Personnel      </option> <option value="../../compendium/index.html">      Compendium      </option> <option value="../index.html">      Course Tutorial      </option> <option value="../../spotID/index.html">      Spot ID      </option> <option value="../../glossary.html">      Glossary      </option> <option value="../../pestframe.html">      NC Pest List      </option> <option 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means of communication. <p> Sound serves as a very effective communication modality.  It can be made to vary in <b>frequency</b> (high pitch vs. low pitch), <b>amplitude</b> (loudness), and <b>periodicity</b> (the temporal pattern of freqency and amplitude).  Together, these three variables can create an extremely wide and complex range of signals -- from an insect's mating call to human speech and vocal music.  Since sound waves move rapidly through air (about 331 m/sec), acoustic signals can be quickly started, stopped, or modified to send a time-sensitive message. <p> <table width="450" align="right"><tr><td> <table width="425" border="1" cellpadding="10" align="right" bgcolor="DDEEFF"> <tr><th><h3>Pros and Cons of Acoustic Communication</th></tr> <tr><td> <dl> <dt><b>     Advantages:</b> <dd><li>Not limited by environmental barriers <dd><li>Effective over distances and around corners <dd><li>Highly variable, fast change -- high information content </dl><dl> <dt><b>     Disadvantages:</b> <dd><li>May reveal location of sender to a potential predator <dd><li>Less effective in "noisy" environments (e.g. seashore) <dd><li>May be metabolically "expensive" to produce <dd><li>Attenuation -- intensity falls rapidly with distance from source (cube-root function) </dl> </td></tr> </table> </td></tr></table> <p> At best, the human ear is able to detect sound frequencies only within the range of about 20-20,000 hertz (vibrations per second).  But some insects (as well as other animals like bats and dolphins) produce and detect sounds that are well above this frequency range.  Some grasshoppers and moths, for example, produce ultrasonic sounds as high as 80,000 hertz.  Entomologists study these high-pitch sounds by using an <a href="https://web.archive.org/web/20110720011820/http://cibra.unipv.it/insec.html">audio transducer</a>, an electronic device that converts inaudible high frequencies to lower audible frequencies. <p> Most insects detect sound with a <b>tympanic mambrane</b> in the abdomen (e.g. grasshoppers and moths) or in the tibiae of the front legs (e.g. crickets and katydids).  Mosquitoes have antennal hairs that resonate to certain frequencies of sound.  But sound vibrations can also travel through solid objects, and some insects (e.g. some species of ants, bees, termites, and treehoppers) can sense <b>substrate vibrations</b> with <a href="/web/20110720011820/http://www.cals.ncsu.edu/course/ent425/tutorial/mechano.html">mechanoreceptors</a> (chordotonal organs) in their legs.  Since these signals are "felt" rather than "heard", they are usually regarded as a form of <a href="tactcomm.html">tactile communication</a>. <p> <big><b>See and hear each insect in the table below by clicking on its common name.</b></big> <br><br> <center> <object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="https://web.archive.org/web/20110720011820oe_/http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,0,0" width="650" height="400" id="insects3a" align="middle"> <param name="allowScriptAccess" value="sameDomain"/> <param name="movie" value="insects3a.swf"/> <param name="quality" value="high"/> <param name="bgcolor" value="#ffffff"/> <embed src="/web/20110720011820oe_/http://www.cals.ncsu.edu/course/ent425/tutorial/Communication/insects3a.swf" quality="high" bgcolor="#ffffff" width="650" height="400" name="insects3a" align="middle" allowscriptaccess="sameDomain" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"/> </object> </center> <p> </td></tr></table> <br><br><br> <table width="250" border="1" cellpadding="10" bgcolor="DDEEFF"><tr><td><center><h3><a href="index.html">Communication</a></td></tr></table> <table width="375" border="1" cellpadding="10" bgcolor="DDEEFF"><tr> <td width="125"><center><h3><a href="tactcomm.html">Tactile</a></td> <td width="125"><center><h3><a href="chemcomm.html">Chemical</a></td> <td width="125"><center><h3><a href="viscomm.html">Visual</a></td> </tr></table> </center> <br><br><br> <hr> <table width="100%"><tr><td width="33%"> <table> Return to <a href="/web/20110720011820/http://www.cals.ncsu.edu/course/ent425/index.html">ENT 425 HomePage</a> <br> Return to <a href="/web/20110720011820/http://www.cals.ncsu.edu/course/ent425/tutorial/index.html">Tutorial Index</a> <br> <i>Last Updated:   16 January 2006</i> </td></tr></table> </td><td width="34%" valign="top"> <center> <table><tr><td> © Copyright 2006<br>All rights reserved </td></tr></table> </center> </td><td width="33%"> <table width="175" align="right"><tr> <td> <a href="https://web.archive.org/web/20110720011820/mailto:john_meyer@ncsu.edu">John R. Meyer</a> <br> Department of Entomology <br>NC State University</td></tr></table> </td></tr></table> <script> Image1 = new Image(); Image1.src = "gryllid.jpg"; Image2 = new Image(); Image2.src = "oecanthus.jpg"; Image3 = new Image(); Image3.src = "femur.gif"; Image4 = new Image(); Image4.src = "tibia.gif"; Image5 = new Image(); Image5.src = "tarsus.gif"; </script> </body> </html>

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Acoustic Communication