Browsing by Author "Moller, Anders P."

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High Levels of Liver Antioxidants Are Associated With Life-History Strategies Characteristic of Slow Growth and High Survival Rates in Birds
(Springer Heidelberg, 2012) Galvan, Ismael; Erritzoe, Johannes; Karadas, Filiz; Moller, Anders P.
Antioxidants have a large potential to coevolve with life-histories because of their capacity to counteract the negative effects of free radicals on fitness. However, only a few studies have explored the association between antioxidant levels and life-history strategies comparing a large number of species. Here we used an extensive dataset of 125 species of birds to investigate the association between concentrations of antioxidants (carotenoids and vitamin E) in the liver, which is the main storage organ for fat-soluble antioxidants, and life-history and morphology. We found that high liver antioxidant concentrations were associated with life-history strategies characterized by "live slow, die old", in clear contrast to previous studies reporting a relationship between high plasma antioxidants and life-histories characterized by "live fast, die young". Thus, high carotenoid concentrations were present in species with large body, brain and egg sizes, high absolute metabolic rate and a resident lifestyle, while high vitamin E concentrations were present in species with large brain size and long life span and incubation period. Our results indicate that antioxidants and life-histories coevolve, and that this may be mediated by positive fitness consequences of the accumulation of liver antioxidants, as species with higher antioxidant levels live longer.
Maternal Effects Mediated by Antioxidants and the Evolution of Carotenoid-Based Signals in Birds
(Univ Chicago Press, 2009) Biard, Clotilde; Gil, Diego; Karadas, Filiz; Saino, Nicola; Spottiswoode, Claire N.; Surai, Peter F.; Moller, Anders P.
Bright yellow to red signals used in mate choice or intrasexual competition are based on carotenoid pigments that are hypothesized to be traded between physiological functions and coloration. These signals have recently been shown to be influenced by maternal effects. Indeed, yolk-derived carotenoids are essential for embryos to develop efficient carotenoid metabolism in posthatching life. Maternal effects facilitate adaptation to environmental variability and influence the evolution of phenotypic traits such as secondary sexual signals. Here we propose that maternal investment in yolk carotenoids promotes the evolution of carotenoid-based ornaments. We conducted a comparative analysis of lipid-soluble antioxidants (carotenoids and vitamins A and E) in the eggs of 112 species of bird. Species with large clutch sizes deposited higher yolk concentrations of the three antioxidants. There was a significant positive relationship between yolk carotenoids and the expression of male carotenoid-based signals, but not between yolk carotenoids and sexual dichromatism in these signals. These relationships were specific to carotenoids, as they were not found for vitamins A and E. This provides evidence consistent with the hypothesis that maternal effects mediated by yolk carotenoids play a role in the evolution of carotenoid-based signals as a response to sexual selection, likely based on organizational effects of carotenoids during embryo development.
A Nondestructive Method for Extracting Maternally Derived Egg Yolk Carotenoids
(Wiley, 2007) Cassey, Phillip; Ewen, John G.; Boulton, Rebecca L.; Karadas, Filiz; Moller, Anders P.; Blackburn, Tim M.
Maternally deposited carotenoids are a prominent component of egg yolk and are vital for the development and growth of the embryo. In most studies of avian yolk carotenoids, eggs are destructively sampled and this may limit both the number of clutches studied and the research questions addressed. We describe an empirical field trial for a nondestructive biopsy method to extract small samples (0.05 ml) of egg yolk for high-performance liquid chromatography (HPLC) analysis of yolk carotenoid concentrations. We sampled 180 clutches (N= 44 biopsies) of two species of introduced thrushes (genus Turdus) from agricultural habitats in central North Island, New Zealand. Once the protocol was established, all biopsied eggs from clutches that were not depredated or deserted before candling were found to be developing normally after 3-5 d of incubation (N= 28) and all hatched. Biopsy samples (> 0.02 g) produced concentrations of yolk carotenoids (and variances) that were statistically indistinguishable from whole yolk destructive samples. In addition, our samples (> 0.02 g) confirmed previously reported differences in yolk carotenoid concentrations between the two thrush species and revealed a significant decline in yolk carotenoid concentration with laying order. Further examination of how variability in yolk carotenoid concentration and identity influences offspring sex, success, and survival or, later in life, reproductive success and ability to efficiently incorporate dietary carotenoids into both integument and immune tissues will require larger sample sizes. Studies to date have been restricted by the number of destructive samples that investigators are willing (or permitted) to obtain from wild species. Thus, we hope that our nondestructive method of sampling yolk will promote further examination of the links between carotenoid uptake from the environment and maternal investment in the avian yolk.