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Color signals in the Black Grouse (Tetrao tetrix) : signal properties and their condition dependency

journal contribution
posted on 01.01.2007, 00:00 authored by H Siitari, R Alatalo, P Halme, Kate BuchananKate Buchanan, J Kilpimaa
Recent progress in techniques of quantifying between‐individual differences of color‐based ornaments has revealed undiscovered possibilities for research in sexual selection. We present how the color spectra data can be comprehensively used for studying the importance of sexual ornaments in the black grouse and how these ornaments are related to a male condition. For this, we used both correlative field and experimental data. Field data indicated that older males had more chromatic coloration than yearlings. Blue chroma of males was correlated with male mating success. We experimentally manipulated yearling birds with testosterone implants and found that testosterone‐implanted males had impaired expression of several sexual ornaments: 10 months after the implantation, both structural‐based blue and carotenoid‐based red eye comb coloration were diminished, as well as lyre (tail) length. However, the manipulation did not affect vital traits under natural selection (wing length or body mass). Our data indicate that structural color is an important trait in sexual selection in this lekking species. Importantly, the data also indicate that male sexual ornaments are more susceptible to environmental conditions than the other male traits, thus showing their heightened condition dependency compared with the other traits mediating the honesty of signaling.

History

Journal

American naturalist

Volume

169

Issue

supplement

Publisher

University of Chicago Press

Location

Chicago, Ill.

ISSN

0003-0147

eISSN

1537-5323

Language

eng

Notes

(published January 2007)

Publication classification

C1.1 Refereed article in a scholarly journal; C Journal article

Copyright notice

2007, The University of Chicago