title: Worldwide patterns of bird colouration on islands.
abstract: Island environments share distinctive characteristics that offer unique opportunities to investigate parallel evolution. Previous research has produced evidence of an island syndrome for morphological traits, life-history strategies and ecological niches, but little is known about the response to insularity of other important traits such as animal signals. Here, we tested whether birds' plumage colouration is part of the island syndrome. We analysed with spectrophotometry the colouration of 116 species endemic to islands and their 116 closest mainland relatives. We found a pattern of reduced brightness and colour intensity for both sexes on islands. In addition, we found a decrease in the number of colour patches on islands that, in males, was associated with a decrease in the number of same-family sympatric species. These results demonstrate a worldwide pattern of parallel colour changes on islands and suggest that a relaxation of selection on species recognition may be one of the mechanisms involved.
authors.affiliation: CEFE UMR 5175, CNRS - Univ. Montpellier - Univ. Paul-Valéry Montpellier- EPHE, 1919 route de Mende, 34293, Montpellier, Cedex 5, France.|Percy FitzPatrick Institute, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa.
authors.forename: Claire
authors.initials: C
authors.lastname: Doutrelant
authors.affiliation: CEFE UMR 5175, CNRS - Univ. Montpellier - Univ. Paul-Valéry Montpellier- EPHE, 1919 route de Mende, 34293, Montpellier, Cedex 5, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Paquet
authors.affiliation: ACTE UMR 8218, CNRS-Univ. Paris 1 Panthéon-Sorbonne, 47 rue des bergers, 75015, Paris, France.
authors.forename: Julien P
authors.initials: JP
authors.lastname: Renoult
authors.affiliation: CEFE UMR 5175, CNRS - Univ. Montpellier - Univ. Paul-Valéry Montpellier- EPHE, 1919 route de Mende, 34293, Montpellier, Cedex 5, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Grégoire
authors.affiliation: CEFE UMR 5175, CNRS - Univ. Montpellier - Univ. Paul-Valéry Montpellier- EPHE, 1919 route de Mende, 34293, Montpellier, Cedex 5, France.
authors.forename: Pierre-André
authors.initials: PA
authors.lastname: Crochet
authors.affiliation: Percy FitzPatrick Institute, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa.|CIBIO-InBio, University of Porto, Rua Monte-Crasto, 4485-661, Vairão, Portugal.|Department of Biology, Science Faculty, University of Porto, Porto, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Covas
mesh_terms: D000818:Animals; D001717:Birds / Q000502:physiology*; D005260:Female; D062312:Islands; D008297:Male; D010858:Pigmentation / Q000502:physiology*; D012641:Selection, Genetic
keywords: Colouration; Goldsmith tetrahedral colour space; Insularity syndrome; Parallel evolution; Sexual selection; Species recognition