Are frog calls modulated by the environment? An analysis with anuran species
from Bolivia
J. Bosch and I. De la Riva
Pages 880-888
Abstract:
Studies have shown that long-range songs of birds and primates are
structurally adapted to local habitat acoustics. The evolution of frog
calls, however, seems to be less influenced by habitat. Frogs are extremely
dependent on energetically costly acoustic signals, which frequently have to
be transmitted over large distances to elicit an encounter with the opposite
sex. Different acoustic properties of advertisement calls from 95 Bolivian
anuran species were analyzed according to their taxonomic position and the
habitat characteristics where each species occurred. The majority of call
characteristics, such as diversity of notes, number of pulses per note, or
dominant frequency, appear strongly related to taxonomic position.
Large-scale habitat characteristics (ecoregion and macrohabitat type) were
not related to call characteristics, whereas small-scale habitat
(microhabitat) complexity appeared to explain some of the variation in
dominant frequency modulation. Species that call in closed microhabitats are
more likely to use frequency-modulated calls, which may allow for more
efficient sound transmission. To further the understanding of frog-call
evolution in response to habitat selection, this and other studies have
indicated that studies at finer spatial scales are needed, as well as
additional studies restricted to the genus or species level.
Conspecifics influence call design in the Brazilian free-tailed bat,
Tadarida brasiliensis
John M. Ratcliffe, Hannah M. ter Hofstede, Rafa Avila-Flores, M. Brock
Fenton, Gary F. McCracken, Stephania Biscardi, Jennifer Blasko, Erin Gillam,
Jasmine Orprecio, and Genvieve Spanjer
Pages 966-971
Abstract:
The Brazilian free-tailed bat, Tadarida brasiliensis (Saint-Hilaire, 1824),
uses calls that represent a broad continuum of design variation which is
dependent upon habitat and situation, and exhibits characteristic changes in
call design as bats close in on airborne targets. Here we demonstrate the
influence of conspecifics on call design. We found that the peak frequency
used in calls varies more as the number of bats flying in the same space
increases (measured from single bats and pairs of bats). We investigated
this phenomenon through comparing call-parameter differences found between
two bats recorded flying together (actual pairs) with call-parameter
differences between two bats each recorded flying alone at different
locations that were randomly assigned to one another (virtual pairs). We
found that actual pairs of bats used calls which differed in peak frequency
more so than did virtual pairs. This result is particularly striking given
that these frequency differences were greater between bats in the same space
than between bats in two different habitats. We argue that these differences
indicate that this species is practicing jamming avoidance, air traffic
control, or both.
>From Tue, 05 Oct 2004 23:51:56 -0700
From: Dave Mellinger <>
To:
Date: Tue, 05 Oct 2004 23:51:56 -0700
Subject: Marine Mammal Science Articles
Message-Id:
From: "Jason Gedamke" <[EMAIL PROTECTED]>
Marine Mammal Science
Volume 20, Number 4
October 2004
TEMPORARY THRESHOLD SHIFTS AFTER NOISE EXPOSURE IN THE BOTTLENOSE DOLPHIN
(TURSIOPS
TRUNCATUS) MEASURED USING EVOKED AUDITORY POTENTIALS. Paul E. Nachtigall,
Alexander
Ya. Supin, Jeffrey Pawloski, and Whitlow W. L. Au, pages 673-687.
EFFECTS OF WATERCRAFT NOISE ON THE ACOUSTIC BEHAVIOR OF BOTTLENOSE DOLPHINS,
TURSIOPS
TRUNCATUS, IN SARASOTA BAY, FLORIDA. Kara C. Buckstaff, pages 709-725.
ABUNDANCE AND POPULATION TREND (1978-2001) OF WESTERN ARCTIC BOWHEAD WHALES
SURVEYED
NEAR BARROW, ALASKA. J. C. "Craig" George, J. Zeh, R. Suydam, and C. Clark,
pages
755-773.
Abstracts available online:
<a
href="http://apt.allenpress.com/aptonline/?request=get-toc&issn=0824-0469&volume=020&issue=04";
rel="nofollow">http://apt.allenpress.com/aptonline/?request=get-toc&issn=0824-0469&volume=020&issue=04</a>
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