title: Geographical trends in the yolk carotenoid composition of the pied flycatcher (Ficedula hypoleuca).
abstract: Carotenoids in the egg yolks of birds are considered to be important antioxidants and immune stimulants during the rapid growth of embryos. Yolk carotenoid composition is strongly affected by the carotenoid composition of the female's diet at the time of egg formation. Spatial and temporal differences in carotenoid availability may thus be reflected in yolk concentrations. To assess whether yolk carotenoid concentrations or carotenoid profiles show any large-scale geographical trends or differences among habitats, we collected yolk samples from 16 European populations of the pied flycatcher, Ficedula hypoleuca. We found that the concentrations and proportions of lutein and some other xanthophylls in the egg yolks decreased from Central Europe northwards. The most southern population (which is also the one found at the highest altitude) also showed relatively low carotenoid levels. Concentrations of β-carotene and zeaxanthin did not show any obvious geographical gradients. Egg yolks also contained proportionally more lutein and other xanthophylls in deciduous than in mixed or coniferous habitats. We suggest that latitudinal gradients in lutein and xanthophylls reflect the lower availability of lutein-rich food items in the northern F. hypoleuca populations and in montane southern populations, which start egg-laying earlier relative to tree phenology than the Central European populations. Similarly, among-habitat variation is likely to reflect the better availability of lutein-rich food in deciduous forests. Our study is the first to indicate that the concentration and profile of yolk carotenoids may show large-scale spatial variation among populations in different parts of the species' geographical range. Further studies are needed to test the fitness effects of this geographical variation.
authors.affiliation: Department of Biology, University of Turku, Turku, Finland. tapio.eeva@utu.fi
authors.forename: Tapio
authors.initials: T
authors.lastname: Eeva
authors.forename: Suvi
authors.initials: S
authors.lastname: Ruuskanen
authors.forename: Juha-Pekka
authors.initials: JP
authors.lastname: Salminen
authors.forename: Eugen
authors.initials: E
authors.lastname: Belskii
authors.forename: Antero
authors.initials: A
authors.lastname: Järvinen
authors.forename: Anvar
authors.initials: A
authors.lastname: Kerimov
authors.forename: Erkki
authors.initials: E
authors.lastname: Korpimäki
authors.forename: Indrikis
authors.initials: I
authors.lastname: Krams
authors.forename: Juan
authors.initials: J
authors.lastname: Moreno
authors.forename: Chiara
authors.initials: C
authors.lastname: Morosinotto
authors.forename: Raivo
authors.initials: R
authors.lastname: Mänd
authors.forename: Markku
authors.initials: M
authors.lastname: Orell
authors.forename: Anna
authors.initials: A
authors.lastname: Qvarnström
authors.forename: Heli
authors.initials: H
authors.lastname: Siitari
authors.forename: Fred M
authors.initials: FM
authors.lastname: Slater
authors.forename: Vallo
authors.initials: V
authors.lastname: Tilgar
authors.forename: Marcel E
authors.initials: ME
authors.lastname: Visser
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Winkel
authors.forename: Herwig
authors.initials: H
authors.lastname: Zang
authors.forename: Toni
authors.initials: T
authors.lastname: Laaksonen
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D001947:Breeding; D002338:Carotenoids / Q000032:analysis* / Q000378:metabolism; D004032:Diet / Q000662:veterinary*; D004530:Egg Yolk / Q000737:chemistry*; D005060:Europe; D005260:Female; D020387:Food Chain; D005843:Geography; D014975:Lutein / Q000032:analysis / Q000378:metabolism; D011157:Population Dynamics; D025341:Principal Component Analysis; D020308:Songbirds / Q000502:physiology*; D014197:Trees / Q000145:classification / Q000502:physiology; D024341:Xanthophylls / Q000032:analysis / Q000378:metabolism; D019207:beta Carotene / Q000032:analysis / Q000378:metabolism
chemical_list: D000975:Antioxidants; D024341:Xanthophylls; D019207:beta Carotene; D002338:Carotenoids; D014975:Lutein