Beco evolutivo sem saída nas ilhas Galápagos: divergência de sinais sexuais nos mais raros dos tentilhões de Darwin

terça-feira, junho 29, 2010

Evolutionary Dead End in the Galápagos: Divergence of Sexual Signals in the Rarest of Darwin's Finches

Henrik Brumm1*, Heather Farrington2, Kenneth Petren2,Birgit Fessl3,4

1 Communication and Social Behaviour Group, Max Planck Institute for Ornithology, Seewiesen, Germany, 2 Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, United States of America, 3 Charles Darwin Research Station, Puerto Ayora, Santa Cruz, Galápagos, Ecuador, 4Durrell Wildlife Conservation Trust, Jersey, Channel Islands, United Kingdom

Mangrove finch Cactospiza heliobates
Source/Fonte: Darwin Foundation

Abstract Top

Understanding the mechanisms underlying speciation remains a challenge in evolutionary biology. The adaptive radiation of Darwin's finches is a prime example of species formation, and their study has revealed many important insights into evolutionary processes. Here, we report striking differences in mating signals (songs), morphology and genetics between the two remnant populations of Darwin's mangrove finch Camarhynchus heliobates, one of the rarest species in the world. We also show that territorial males exhibited strong discrimination of sexual signals by locality: in response to foreign songs, males responded weaker than to songs from their own population. Female responses were infrequent and weak but gave approximately similar results. Our findings not only suggest speciation in the mangrove finch, thereby providing strong support for the central role of sexual signals during speciation, but they have also implications for the conservation of this iconic bird. If speciation is complete, the eastern species will face imminent extinction, because it has a population size of only 5–10 individuals.

Citation: Brumm H, Farrington H, Petren K, Fessl B (2010) Evolutionary Dead End in the Galápagos: Divergence of Sexual Signals in the Rarest of Darwin's Finches. PLoS ONE 5(6): e11191. doi:10.1371/journal.pone.0011191

Editor: David Reby, University of Sussex, United Kingdom

Received: March 17, 2010; Accepted: May 20, 2010; Published: June 23, 2010

Copyright: © 2010 Brumm et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: Funding was provided by the United Kingdom government's Darwin Initiative Fund (project #15005), the German Research Foundation (award Br 2309/6-1), and the Association for the Study of Animal Behaviour (Christopher Barnard Award for Outstanding Contributions by a New Investigator to HB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

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