title: Egg-laying capacity is limited by carotenoid pigment availability in wild gulls Larus fuscus.
abstract: In birds, experimentally increased egg production can reduce maternal condition, parenting ability and survival, and the quality of the eggs themselves. Such costs probably reflect resource limitation, but the identity of the resource(s) in question remains unclear. Carotenoids are antioxidants and immunomodulants that birds can only obtain in their diet. Trade-offs in the allocation of limiting carotenoids between somatic maintenance and egg production could therefore be an important factor underlying reproductive costs. We show that in wild lesser black-backed gulls, Larus fuscus, dietary carotenoid availability (i) constrained the capacity to re-lay following clutch removal; and (ii) affected the relationship between yolk mass and egg mass. However, whether carotenoids are limiting for egg production directly, by stimulating the synthesis or antioxidant protection of yolk precursors, or indirectly via effects on maternal health, requires further study.
authors.affiliation: Division of Environmental and Evolutionary Biology, Graham Kerr Building, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK. j.blount@bio.gla.ac.uk
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Blount
authors.forename: David C
authors.initials: DC
authors.lastname: Houston
authors.forename: Peter F
authors.initials: PF
authors.lastname: Surai
authors.forename: Anders Pape
authors.initials: AP
authors.lastname: Møller
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001717:Birds / Q000502:physiology*; D002338:Carotenoids / Q000494:pharmacology*; D008098:Litter Size; D010058:Oviposition / Q000187:drug effects* / Q000502:physiology; D010063:Ovum / Q000166:cytology* / Q000502:physiology; D006113:United Kingdom
chemical_list: D002338:Carotenoids