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Barbara Tschirren - One of the best experts on this subject based on the ideXlab platform.
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proximate mechanisms of variation in the Carotenoid based plumage coloration of nestling great tits parus major l
Journal of Evolutionary Biology, 2003Co-Authors: Barbara TschirrenAbstract:Many vertebrates use Carotenoid-based signals in social or sexual interactions. Honest signalling via Carotenoids implies some limitation of Carotenoid-based colour expression among phenotypes in the wild, and at least five limiting proximate mechanisms have been hypothesized. Limitation may arise by Carotenoid-availability, genetic constraints, body condition, parasites, or detrimental effects of Carotenoids. An understanding of the relative importance of the five mechanisms is relevant in the context of natural and sexual selection acting on signal evolution. In an experimental field study with Carotenoid supplementation, simultaneous cross-fostering, manipulation of brood size and ectoparasite load, we investigated the relative importance of these mechanisms for the variation in Carotenoid-based coloration of nestling great tits (Parus major). Carotenoid-based plumage coloration was significantly related to genetic origin of nestlings, and was enhanced both in Carotenoid-supplemented nestlings, and nestlings raised in reduced broods. We found a tendency for ectoparasite-induced limitation of colour expression and no evidence for detrimental effects of Carotenoids on growth pattern, mortality and recruitment of nestlings to the local breeding population. Thus, three of the five proposed mechanisms can generate individual variation in the expression of Carotenoid-based plumage coloration in the wild and thus could maintain honesty in a trait potentially used for signalling of individual quality.
Staffan Andersson - One of the best experts on this subject based on the ideXlab platform.
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parental effects on Carotenoid based plumage coloration in nestling great tits parus major
Behavioral Ecology and Sociobiology, 2006Co-Authors: Caroline Isaksson, Tobias Uller, Staffan AnderssonAbstract:Carotenoid pigments have attracted much interest in behavioural and evolutionary ecology because of their dual function in immune physiology and as color signals. In vertebrates, Carotenoids must ultimately be obtained from the diet, and the mechanisms and magnitude of this environmental dependence are central for understanding Carotenoid signal functions and evolution. In the present cross-fostering experiment with great tits Parus major, we investigate pre- and postnatal parental effects (egg yolk Carotenoids, parental coloration) on nestling size and Carotenoid coloration, using HPLC analysis of egg yolk Carotenoids, and a reflectance-based measure of ‘chroma’ that reflects the plumage pigment concentration. Both rearing environment and origin influenced offspring size and plumage chroma. Maternal allocation of Carotenoids to eggs had a weak positive effect on nestling plumage chroma, whereas we found no prenatal maternal effects (egg size or yolk Carotenoid concentration) on size. Nestling plumage chroma was also significantly predicted by the chroma of the rearing father, but not by the color of the rearing mother or either of the original (genetical) parents. Thus, both prenatal maternal effects and postnatal paternal effects influence the Carotenoid-based plumage coloration of nestling great tits. Future studies will reveal if parental effects have long-term consequences for plumage development and associated fitness components.
Tobias Uller - One of the best experts on this subject based on the ideXlab platform.
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parental effects on Carotenoid based plumage coloration in nestling great tits parus major
Behavioral Ecology and Sociobiology, 2006Co-Authors: Caroline Isaksson, Tobias Uller, Staffan AnderssonAbstract:Carotenoid pigments have attracted much interest in behavioural and evolutionary ecology because of their dual function in immune physiology and as color signals. In vertebrates, Carotenoids must ultimately be obtained from the diet, and the mechanisms and magnitude of this environmental dependence are central for understanding Carotenoid signal functions and evolution. In the present cross-fostering experiment with great tits Parus major, we investigate pre- and postnatal parental effects (egg yolk Carotenoids, parental coloration) on nestling size and Carotenoid coloration, using HPLC analysis of egg yolk Carotenoids, and a reflectance-based measure of ‘chroma’ that reflects the plumage pigment concentration. Both rearing environment and origin influenced offspring size and plumage chroma. Maternal allocation of Carotenoids to eggs had a weak positive effect on nestling plumage chroma, whereas we found no prenatal maternal effects (egg size or yolk Carotenoid concentration) on size. Nestling plumage chroma was also significantly predicted by the chroma of the rearing father, but not by the color of the rearing mother or either of the original (genetical) parents. Thus, both prenatal maternal effects and postnatal paternal effects influence the Carotenoid-based plumage coloration of nestling great tits. Future studies will reveal if parental effects have long-term consequences for plumage development and associated fitness components.
Anders Møller - One of the best experts on this subject based on the ideXlab platform.
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Carotenoid availability in diet and phenotype of blue and great tit nestlings
Journal of Experimental Biology, 2006Co-Authors: Clotilde Biard, P F Surai, Anders MøllerAbstract:Carotenoids are biologically active pigments of crucial importance for the development of avian embryos and nestlings. Thus parental ability to provide nestlings with a Carotenoid-rich diet may enhance offspring fitness. However, very little is known about the possible effects of Carotenoid availability in the diet on growing nestlings in natural populations. We experimentally manipulated dietary intake of Carotenoids by nestlings of two closely related passerine species, the great tit Parus major and the blue tit Parus caeruleus, and measured nestling antioxidants, body condition, immunity and plumage colour. There was no detectable increase in plasma Carotenoids after treatment in Carotenoid-fed nestlings of either species despite regular supply of dietary Carotenoids. However, in Carotenoid-fed blue tit nestlings, plasma vitamin E concentration increased with plasma Carotenoid concentration, while that was not the case for control nestlings. In both species, there was no significant effect of Carotenoid supply on immune function. Carotenoid supplementation enhanced yellow feather colour in great tit nestlings only. In both species a strong effect of Carotenoid supply was found on body condition with an increase in body mass for small Carotenoid-fed nestlings compared to similarly sized control nestlings. Dietary availability of Carotenoids may thus have important fitness consequences for tits. We hypothesise that the difference in effect of dietary Carotenoids on the two species is due to relatively larger clutch size and higher growth rates of blue tits compared to great tits, leading to blue tit nestlings being more in need of Carotenoids for antioxidant function than great tit nestlings.
Geoffrey E Hill - One of the best experts on this subject based on the ideXlab platform.
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plumage redness signals mitochondrial function in the house finch
bioRxiv, 2019Co-Authors: Geoffrey E Hill, Wendy R Hood, Zhiyuan Ge, Rhys Grinter, Chris Greening, James D Johnson, Noel R Park, Halie A Taylor, Victoria A AndreasenAbstract:Abstract Carotenoid coloration is widely recognized as a signal of individual condition in various animals, but despite decades of study, the mechanisms that link Carotenoid coloration to condition remain unresolved. Most birds with red feathers convert yellow dietary Carotenoids to red Carotenoids in an oxidation process requiring the gene encoding the putative cytochrome P450 enzyme CYP2J19. Here, we tested the hypothesis that the process of Carotenoid oxidation and feather pigmentation is functionally linked to mitochondrial performance. Consistent with this hypothesis, we observed high levels of red ketolated Carotenoids associated with the hepatic mitochondria of molting wild house finches (Haemorhous mexicanus), and upon fractionation, we found the highest concentration of ketolated Carotenoids in the inner mitochondrial membrane. We further found that the redness of growing feathers was positively related to the performance of liver mitochondria. Structural modeling of CYP2J19 supports a direct role of this protein in Carotenoid ketolation that may be functionally linked to cellular respiration. These observations suggest that feather coloration serves as a signal of core functionality through inexorable links to cellular respiration in the mitochondria.
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no evidence that Carotenoid pigments boost either immune or antioxidant defenses in a songbird
Nature Communications, 2018Co-Authors: Wendy R Hood, Rebecca E Koch, Andreas N Kavazis, Dennis Hasselquist, Matthew B Toomey, Yufeng Zhang, Geoffrey E HillAbstract:Dietary Carotenoids have been proposed to boost immune system and antioxidant functions in vertebrate animals, but studies aimed at testing these physiological functions of Carotenoids have often failed to find support. Here we subject yellow canaries (Serinus canaria), which possess high levels of Carotenoids in their tissue, and white recessive canaries, which possess a knockdown mutation that results in very low levels of tissue Carotenoids, to oxidative and pathogen challenges. Across diverse measures of physiological performance, we detect no differences between Carotenoid-rich yellow and Carotenoid-deficient white canaries. These results add further challenge to the assumption that Carotenoids are directly involved in supporting physiological function in vertebrate animals. While some dietary Carotenoids provide indirect benefits as retinoid precursors, our observations suggest that Carotenoids themselves may play little to no direct role in key physiological processes in birds.
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dietary Carotenoids predict plumage coloration in wild house finches
Proceedings of The Royal Society B: Biological Sciences, 2002Co-Authors: Geoffrey E Hill, Caron Y Inouye, Robert MontgomerieAbstract:Carotenoid pigments are a widespread source of ornamental coloration in vertebrates and expression of Carotenoid-based colour displays has been shown to serve as an important criterion in female mate choice in birds and fishes. Unlike other integumentary pigments, Carotenoids cannot be synthesized; they must be ingested. Carotenoid-based coloration is condition-dependent and has been shown to be affected by both parasites and nutritional condition. A controversial hypothesis is that the expression of Carotenoid-based coloration in wild vertebrates is also affected by the amount and types of Carotenoid pigments that are ingested. We tested this Carotenoid-limitation hypothesis by sampling the gut contents of moulting house finches and comparing the concentration of Carotenoid pigments in their gut contents with the colour of growing feathers. We found a positive association: males that ingested food with a higher concentration of Carotenoid pigments grew brighter ornamental plumage. We also compared the concentration of Carotenoids in the gut contents of males from two subspecies of house finches with small and large patches of Carotenoid-based coloration. Consistent with the hypothesis that Carotenoid access drives the evolution of Carotenoid-based colour displays, males from the population with limited ornamentation had much lower concentrations of Carotenoids in their gut contents than males from the population with extensive ornamentation. These observations support the idea that Carotenoid intake plays a part in determining the plumage brightness of male house finches.
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the influence of Carotenoid acquisition and utilization on the maintenance of species typical plumage pigmentation in male american goldfinches carduelis tristis and northern cardinals cardinalis cardinalis
Physiological and Biochemical Zoology, 2001Co-Authors: Kevin J. Mcgraw, Geoffrey E Hill, Riccardo Stradi, Robert S. ParkerAbstract:Abstract Birds display a tremendous variety of Carotenoid‐based colors in their plumage, but the mechanisms underlying interspecific variability in Carotenoid pigmentation remain poorly understood. Because vertebrates cannot synthesize Carotenoids de novo, access to pigments in the diet is one proximate factor that may shape species differences in Carotenoid‐based plumage coloration. However, some birds metabolize ingested Carotenoids and deposit pigments that differ in color from their dietary precursors, indicating that metabolic capabilities may also contribute to the diversity of plumage colors we see in nature. In this study, we investigated how the acquisition and utilization of Carotenoids influence the maintenance of species‐typical plumage pigmentation in male American goldfinches (Carduelis tristis) and northern cardinals (Cardinalis cardinalis). We supplemented the diet of captive goldfinches with red Carotenoids to determine whether males, which are typically yellow in color, were capable of g...
