title: Iridophores and not carotenoids account for chromatic variation of carotenoid-based coloration in common lizards (Lacerta vivipara).
abstract: Abstract Carotenoids typically need reflective background components to shine. Such components, iridophores, leucophores, and keratin- and collagen-derived structures, are generally assumed to show no or little environmental variability. Here, we investigate the origin of environmentally induced variation in the carotenoid-based ventral coloration of male common lizards (Lacerta vivipara) by investigating the effects of dietary carotenoids and corticosterone on both carotenoid- and background-related reflectance. We observed a general negative chromatic change that was prevented by β-carotene supplementation. However, chromatic changes did not result from changes in carotenoid-related reflectance or skin carotenoid content but from changes in background-related reflectance that may have been mediated by vitamin A1. An in vitro experiment showed that the encountered chromatic changes most likely resulted from changes in iridophore reflectance. Our findings demonstrate that chromatic variation in carotenoid-based ornaments may not exclusively reflect differences in integumentary carotenoid content and, hence, in qualities linked to carotenoid deposition (e.g., foraging ability, immune response, or antioxidant capacity). Moreover, skin carotenoid content and carotenoid-related reflectance were related to male color polymorphism, suggesting that carotenoid-based coloration of male common lizards is a multicomponent signal, with iridophores reflecting environmental conditions and carotenoids reflecting genetically based color morphs.
authors: Department of Ecology and Evolution, University of Lausanne, Biophore, 1015 Lausanne, Switzerland. luis.sanjosegarcia@unil.ch
authors: Luis M
authors: LM
authors: San-Jose
authors: Fernando
authors: F
authors: Granado-Lorencio
authors: Barry
authors: B
authors: Sinervo
authors: Patrick S
authors: PS
authors: Fitze
mesh_terms: D000704:Analysis of Variance; D000819:Animal Communication; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002856:Chromatophores / Q000502:physiology*; D003116:Color; D003345:Corticosterone / Q000008:administration & dosage / Q000097:blood; D019587:Dietary Supplements; D008116:Lizards / Q000502:physiology*; D014975:Lutein / Q000097:blood; D008297:Male; D015233:Models, Statistical; D012727:Sex Characteristics; D012880:Skin Pigmentation / Q000502:physiology*; D013030:Spain; D013057:Spectrum Analysis; D024341:Xanthophylls / Q000008:administration & dosage / Q000097:blood / Q000502:physiology; D019207:beta Carotene / Q000097:blood
chemical_list: D024341:Xanthophylls; D019207:beta Carotene; D003345:Corticosterone; D014975:Lutein