2+ bat echolocation articles in Nature

[Matt Heavner <>]

<tt>Nature has published two articles on bat echolocation, along with a 
 commentary/summary of the articles.</tt><br>
 <br>
 <pre style="margin: 0em;">The summary is:</pre><br>
 <pre style="margin: 0em;">Nature 429, 612 - 613 (10 June 2004); 
doi:10.1038/429612a</pre><br>
 <pre style="margin: 0em;">Animal Behaviour: Eavesdropping on bats</pre><br>
 <pre style="margin: 0em;">BROCK FENTON AND JOHN RATCLIFFE</pre><br>
 <tt>1 Brock Fenton is in the Department of Biology, University of Western 
 Ontario, London, Ontario N6A 5B7, Canada.<br>
 e-mail: [EMAIL PROTECTED]<br>
 2 John Ratcliffe is in the Department of Zoology, University of Toronto 
 at Mississauga, Ontario L5L 1C6, Canada.<br>
 e-mail: [EMAIL PROTECTED]</tt><br>
 <br>
 <tt>Two investigations into bat echolocation provide striking examples of 
 the sophistication and the possible evolutionary and ecological 
 consequences of variability in call design.</tt><br>
 <br>
 <pre style="margin: 
0em;">---------------------------------------------------------------</pre><br>
 <pre style="margin: 0em;">The two articles are:</pre><br>
 <pre style="margin: 0em;">Nature 429, 657 - 661 (10 June 2004); 
doi:10.1038/nature02547</pre><br>
 <tt>Echolocation signals reflect niche differentiation in five sympatric 
 congeneric bat species</tt><br>
 <br>
 <pre style="margin: 0em;">BJ&#xD6;RN M. SIEMERS AND HANS-ULRICH 
SCHNITZLER</pre><br>
 <tt>Animal Physiology, Zoological Institute, University of T&#xFC;bingen, 
 Morgenstelle 28, 72076 T&#xFC;bingen, Germany</tt><br>
 <br>
 <tt>Correspondence and requests for materials should be addressed to B.M.S. 
 ([EMAIL PROTECTED]).</tt><br>
 <br>
 <tt><br>Echolocating bats can be divided into guilds according to their 
 preferred habitat and foraging behaviour1-4, which coincide with 
 distinct adaptations in wing morphology5 and structure of echolocation 
 signals6. Although coarse structuring of niche space between different 
 guilds is generally accepted, it is not clear how niches differ within 
 guilds7-10, or whether there is fine-grained niche differentiation 
 reflected in echolocation signal structure11, 12. Using a standardized 
 performance test, here we show clutter-dependent differences in 
 prey-capture success for bats from five species of European Myotis. 
 These species are morphologically similar, sympatric13, and all belong 
 to the guild labelled "edge space aerial/trawling foragers"4. We further 
 demonstrate a strong correlation between the prey-detection ability of 
 the species and the respective search-call bandwidth. Our findings 
 indicate that differences in echolocation signals contribute to 
 within-guild niche differentiation. This is the first study relating 
 sensory abilities of a set of potentially competing animal species to a 
 direct measure of their respective foraging performance, suggesting an 
 important role of sensory ecology in the structuring of animal 
communities.</tt><br>
 <br>
 <pre style="margin: 
0em;">------------------------------------------------------</pre><br>
 <pre style="margin: 0em;">Nature 429, 654 - 657 (10 June 2004); 
doi:10.1038/nature02487</pre><br>
 <pre style="margin: 0em;">Harmonic-hopping in Wallacea's bats</pre><br>
 <pre style="margin: 0em;">TIGGA KINGSTON AND STEPHEN J. ROSSITER</pre><br>
 <tt>1 Department of Geography, Boston University, Massachusetts 02215, USA<br>
 2 School of Biological Sciences, Queen Mary, University of London, 
 London E1 4NS, UK<br>
 3 School of Biological Sciences, University of Bristol, Bristol BS8 1UG, UK<br>
 * These authors contributed equally to this work</tt><br>
 <br>
 <tt>Correspondence and requests for materials should be addressed to T.K. 
 ([EMAIL PROTECTED]). Accession numbers for new and published sequences are 
 AY568637&#x2013;AY568646, and AF065069&#x2013;AF065073 and AF065090 (ref. 12), 
 respectively.</tt><br>
 <br>
 <tt>Evolutionary divergence between species is facilitated by ecological 
 shifts, and divergence is particularly rapid when such shifts also 
 promote assortative mating. Horseshoe bats are a diverse Old World 
 family (Rhinolophidae) that have undergone a rapid radiation in the past 
 5 million years. These insectivorous bats use a predominantly pure-tone 
 echolocation call matched to an auditory fovea (an over-representation 
 of the pure-tone frequency in the cochlea and inferior colliculus) to 
 detect the minute changes in echo amplitude and frequency generated when 
 an insect flutters its wings. The emitted signal is the accentuated 
 second harmonic of a series in which the fundamental and remaining 
 harmonics are filtered out. Here we show that three distinct, sympatric 
 size morphs of the large-eared horseshoe bat (Rhinolophus 
 philippinensis) echolocate at different harmonics of the same 
 fundamental frequency. These morphs have undergone recent genetic 
 divergence, and this process has occurred in parallel more than once. We 
 suggest that switching harmonics creates a discontinuity in the bats' 
 perception of available prey that can initiate disruptive selection. 
 Moreover, because call frequency in horseshoe bats has a dual function 
 in resource acquisition and communication, ecological selection on 
 frequency might lead to assortative mating and ultimately reproductive 
 isolation and speciation, regardless of external barriers to gene 
flow.</tt><br>
 <br>
 <pre style="margin: 0em;"><br>--
 | Matt Heavner, Assistant Professor of Physics
 | University of Alaska Southeast
 | 11120 Glacier Highway, Juneau, AK 99801
 | Phone: (907) 465-6403
 | If Heisenberg was uncertain, why are you so sure?</pre><br>