Recent northward range expansion promotes song evolution in a passerine bird, the Light-vented Bulbul

Authors

  • X. Y. Xing,

    1. Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
    2. University of Chinese Academy of Sciences, Beijing, China
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  • P. Alström,

    Corresponding author
    1. Swedish Species Information Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden
    • Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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  • X. J. Yang,

    1. School of Environmental Studies, China University of Geosciences, Wuhan, China
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  • F. M. Lei

    Corresponding author
    • Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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  • Data deposited at Dryad: doi: 10.5061/dryad.dm821

Correspondence: Fumin Lei and Per Alström, Institute of Zoology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China. Tel.: +86 6 480 7159; fax: +86 6 480 7159; e-mails: leifm@ioz.ac.cn, per.alstrom@slu.se

Abstract

In common with human speech, song is culturally inherited in oscine passerine birds (‘songbirds’). Intraspecific divergence in birdsong, such as development of local dialects, might be an important early step in the speciation process. It is therefore vital to understand how songs diverge, especially in founding populations. The northward expansion of the Light-vented Bulbul Pycnonotus sinensis (J. F. Gmelin, 1789) into north China in the last 30 years provides an excellent opportunity to study birdsong evolution. We compared ~4400 songs from newly established northern populations with ~2900 songs from southern populations to evaluate song divergence after recent expansion. The total pool of syllables and especially song types was considerably smaller in the north than in the south, indicating ‘founder effects’ in the new population. The ancestral pattern of mosaic song dialects changed into a pattern of wide geographical sharing of a few song types and syllables, likely the result of fewer geographical barriers to ‘meme flow’, and the recent spread across a large area in the north. Our results suggest that song evolution and vocal trait shifts can arise rapidly after range expansion, and that in the Light-vented Bulbul ‘founder effects’, geographical isolation, and recent rapid expansions played important roles in the evolution of song dialects.

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