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Re: Bioacoustics in Biological Journal of the Linnean Society

To: Cornell BIOACOUSTICLIST <>
Subject: Re: Bioacoustics in Biological Journal of the Linnean Society
From: Jérôme Sueur <>
Date: Fri, 12 Jan 2007 20:03:01 +0100
and also:

Acoustic adaptations of periodical cicadas (Hemiptera: Magicicada)

UTA OBERDÖRSTER & PETER R. GRANT

Biological Journal of the Linnean Society, 2007, 90, 15–24.

Abstract

We studied the trade-off between traits that function in mate attraction and those that function in enemy avoidance by contrasting features of acoustic communication in cicadas differentially at risk to predators in the same environment. Two genera of North American cicadas were studied: Magicicada and Tibicen. Magicicada species of periodical cicadas, with
17-year life cycles, seek mates in dense aggregations of calling males
that are made possible by the relative ineffectiveness of predators to
control their numbers. During the breeding season, Magicicada are so
abundant that they satiate their predators. From their relative freedom
from predation, it is to be expected that traits for attracting mates
are emphasized in Magicicada compared with the more solitary genus
Tibicen, which reproduce at much lower densities. Males of solitary
species are expected to sing more loudly and at low pitch because both
features enhance long-distance transmission. These two features were
confirmed by measurement. Magicicada septendecim appears to be the most
divergent species, evolutionarily, in terms of an unusually sharply
tuned sound resonating system, low resonant frequency, and quietness of
its song that cannot be entirely explained by body size. These
characteristics represent adaptations to the problem of communicating
unambiguously to females at close range in a loud and heterogeneous
sound environment. Sensitivity to predators, parasitoids, and congeneric species may also have shaped the evolution of their communication systems.




Alan McElligott a écrit :
Song divergence at the edge of Amazonia: an empirical test of the
peripatric speciation model
NATHALIE SEDDON
Biological Journal of the Linnean Society, 2007, 90, 173-188.

Abstract
 The evolutionary divergence of mating signals provides a powerful basis for 
animal speciation. Divergence in sympatry strengthens reproductive isolation, and 
divergence in allopatry can reduce or eliminate gene flow between populations on 
secondary contact. In birds, the first of these processes has empirical support, 
but the second remains largely hypothetical. This is perhaps because most studies 
have focused on oscine passerines, whose song learning ability may reduce the 
influence of vocalizations in reproductive isolation. In suboscine passerines, the 
role of learning in song development is thought to be minimal, and the resultant 
signals are relatively fixed. To investigate the role of song in the early stages 
of peripatric speciation, we therefore studied a suboscine, the chestnut-tailed 
antbird Myrmeciza hemimelaena. We recorded male songs in a natural forest island 
(isolated for < 3000 years) at the southern fringe of Amazonia, and at two 
nearby sites in continuous
 forest. A previous study found the isolated population to be weakly 
differentiated genetically from the ancestral population suggesting that 
peripatric speciation was underway. In support of this, although we detected 
minor but significant differences in song structure between each site, the most 
divergent songs were those of island birds. On simulating secondary contact 
using playback, we found that pairs from the forest island responded more 
strongly to island (i.e. local) songs than to those from both non-island sites, 
and vice versa. This pattern was not observed in pairs from one non-island 
site, which responded with equal strength to local songs and songs from the 
other non-island site. Island females were more likely to approach and sing 
after hearing local male songs, rather than songs from the non-island 
populations, and vice versa; non-island females did not appear to discriminate 
between local songs and those from the other non-island site. These findings 
are cons
 istent with the idea that vocal divergence arising in small populations at the 
edge of Amazonia may result in partial reproductive isolation when contact is 
resumed. They also suggest the possibility that song divergence in peripatry 
may, after much longer time-frames, act as a barrier to gene flow in 
suboscines, perhaps because of an inability to learn or recognize divergent 
songs on secondary contact.


~ ~  ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Dr. Alan McElligott
The School of Biology
Biology Building
The University of Nottingham
University Park
Nottingham NG7 2RD
UK

Tel + 44 (0) 115 951 3231
Fax + 44 (0) 115 951 3251
http://www.nottingham.ac.uk/biology/





--

__________________________________________________

Institut de Recherche sur la Biologie de l'Insecte
CNRS UMR 6035
Université de Tours, faculté des Sciences
Parc Grandmont
37200 Tours

http://www.univ-tours.fr/irbi/
http://sueur.jerome.neuf.fr




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