Geographical trends in the yolk carotenoid composition of the pied flycatcher (Ficedula hypoleuca).
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.
Eeva
Tapio
T
Department of Biology, University of Turku, Turku, Finland. tapio.eeva@utu.fi
Ruuskanen
Suvi
S
Salminen
Juha-Pekka
JP
Belskii
Eugen
E
Järvinen
Antero
A
Kerimov
Anvar
A
Korpimäki
Erkki
E
Krams
Indrikis
I
Moreno
Juan
J
Morosinotto
Chiara
C
Mänd
Raivo
R
Orell
Markku
M
Qvarnström
Anna
A
Siitari
Heli
H
Slater
Fred M
FM
Tilgar
Vallo
V
Visser
Marcel E
ME
Winkel
Wolfgang
W
Zang
Herwig
H
Laaksonen
Toni
T
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
D000975:Antioxidants; D024341:Xanthophylls; D019207:beta Carotene; D002338:Carotenoids; D014975:Lutein