Decreased Fecal Corticosterone Levels Due to Domestication: A Comparison Between the White-Backed Munia (Lonchura striata) and Its Domesticated Strain, the Bengalese Finch (Lonchura striata var. domestica) With a Suggestion for Complex Song Evolution

Authors

  • Kenta Suzuki,

    1. JST, ERATO, Okanoya Emotional Information Project, Wako, Saitama, Japan
    2. Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama, Japan
    3. Laboratory for Biolinguistics, RIKEN Brain Science Institute, Wako, Saitama, Japan
    4. Emotional Information Joint Research Laboratory, RIKEN Brain Science Institute, Wako, Saitama, Japan
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  • Hiroko Yamada,

    1. Laboratory for Biolinguistics, RIKEN Brain Science Institute, Wako, Saitama, Japan
    2. Department of Ocean Science, Tokyo University of Marine Science and Technology, Minato-ku, Tokyo, Japan
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  • Tetsuya Kobayashi,

    1. Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama, Japan
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  • Kazuo Okanoya

    Corresponding author
    1. JST, ERATO, Okanoya Emotional Information Project, Wako, Saitama, Japan
    2. Laboratory for Biolinguistics, RIKEN Brain Science Institute, Wako, Saitama, Japan
    3. Emotional Information Joint Research Laboratory, RIKEN Brain Science Institute, Wako, Saitama, Japan
    • Department of Life Sciences, Graduate School of Arts and Sciences, the University of Tokyo, Meguro-ku, Tokyo, Japan
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ERATO, Okanoya Emotional Information Project, Hirosawa 2-1, Wako, Saitama 351-0198, Japan. Email: kazuookanoya@gmail.com

Abstract

The Bengalese finch (BF; Lonchura striata var. domestica) is a domesticated strain of the white-backed munia (WBM; Lonchura striata). Environmental stresses activate the hypothalamic–pituitary–adrenal (HPA) axis and release corticosterone (CORT). We hypothesized that domesticated songbirds have reduced CORT levels because of reduced levels of environmental stresses (compared to wild conditions) and reductions in the role of CORT, which is necessary for survival in the wild. However, no study has examined the effects of domestication on songbird CORT levels. To explore the domestication effects, we compared CORT levels between domesticated BFs and their wild ancestors WBMs. We also compared CORT levels between bought and aviary-raised BFs, and between wild-caught and captive-raised WBMs to examine the influence of being raised. However, blood collection causes stress, which affects endocrine dynamics and makes continuous sampling difficult in small birds. Therefore, we used a non-invasive method to measure fecal CORT. Parallelism between diluted fecal extracts and a CORT standard, extraction efficiency, and ACTH challenge demonstrated the effectiveness of this method. This study demonstrates that BFs have lower fecal CORT than do WBMs, regardless of whether the WBMs were wild-caught or captive-raised. In addition, BFs sing more complex songs than WBMs. Considerable evidence suggests that song complexity is related to CORT levels. Previously, we found that the corticosteroid receptors were expressed in song-control areas of the BF brain. Based on these results, we hypothesize that reduced CORT levels through domestication might be one factor allowing for the development of more complex songs in BFs. J. Exp. Zool. 317A:561–570, 2012. © 2012 Wiley Periodicals, Inc.

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