title: Geographic variation in breeding system and environment predicts melanin-based plumage ornamentation of male and female Kentish plovers.
abstract: Sexual selection determines the elaboration of morphological and behavioural traits and thus drives the evolution of phenotypes. Sexual selection on males and females can differ between populations, especially when populations exhibit different breeding systems. A substantial body of literature describes how breeding systems shape ornamentation across species, with a strong emphasis on male ornamentation and female preference. However, whether breeding system predicts ornamentation within species and whether similar mechanisms as in males also shape the phenotype of females remains unclear. Here, we investigate how different breeding systems are associated with male and female ornamentation in five geographically distinct populations of Kentish ploversCharadrius alexandrinus. We predicted that polygamous populations would exhibit more elaborate ornaments and stronger sexual dimorphism than monogamous populations. By estimating the size and intensity of male (n= 162) and female (n= 174) melanin-based plumage ornaments, i.e. breast bands and ear coverts, we show that plumage ornamentation is predicted by breeding system in both sexes. A difference in especially male ornamentation between polygamous (darker and smaller ornaments) and monogamous (lighter and larger) populations causes the greatest sexual dimorphism to be associated with polygamy. The non-social environment, however, may also influence the degree of ornamentation, for instance through availability of food. We found that, in addition to breeding system, a key environmental parameter, rainfall, predicted a seasonal change of ornamentation in a sex-specific manner. Our results emphasise that to understand the phenotype of animals, it is important to consider both natural and sexual selection acting on both males and females.
authors.affiliation: Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY UK.
authors.forename: Araceli
authors.initials: A
authors.lastname: Argüelles-Ticó
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN UK ; Institute of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
authors.forename: Clemens
authors.initials: C
authors.lastname: Küpper
authors.affiliation: Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY UK.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Kelsh
authors.affiliation: Department of Ecology, Faculty of Veterinary Science, Szent Istvan University, Rottenbiller u. 50, H-1077 Budapest, Hungary ; MTA-DE "Lendület" Behavioural Ecology Research Group, Department of Evolutionary Zoology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Kosztolányi
authors.affiliation: Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY UK.
authors.forename: Tamás
authors.initials: T
authors.lastname: Székely
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN UK.
authors.forename: René E
authors.initials: RE
authors.lastname: van Dijk
keywords: Breeding system; Kentish plover; Melanin; Ornamentation; Sexual selection