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Richard O. Prum - One of the best experts on this subject based on the ideXlab platform.
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constraint and function in the predefinitive Plumages of manakins aves pipridae
Integrative and Comparative Biology, 2021Co-Authors: Laura M Schaedler, Richard O. Prum, Liam U Taylor, Marina AnciaesAbstract:Birds with delayed Plumage maturation exhibit a drab predefinitive Plumage, often despite gonad maturation, before developing the definitive Plumage associated with increased reproductive success. Manakins are a diverse clade of neotropical lekking birds with extreme sexual dichromatism, radical sexual displays, and a unique diversity in the predefinitive Plumages of males across species. Here, we provide the first full review of the natural history of manakin predefinitive Plumages as the basis for qualitatively addressing the six major hypotheses about the production and function of predefinitive Plumages. We find little evidence to support the possibilities that manakin predefinitive Plumages are directly constrained by inflexible molt schedules, resource limitations to definitive coloration, or hormonal ties to reproductive behaviors. There is little evidence that could support a crypsis function, although direct experimentation is needed, and mimicry is refuted except for one unusual species in which predefinitive males sire young. Instead, evidence from a handful of well-studied species suggests that predefinitive Plumages help young males explicitly signal their social status, and thereby gain entry to the social hierarchies which dictate future reproductive success. Our conclusions are especially influenced by the unique fact that males of at least 11 species throughout the family exhibit multiple predefinitive Plumage stages with distinctively male patches. For each hypothesis, we highlight ways in which a better knowledge of female and young male birds offers critical opportunities for the use of manakins as a model clade.
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convergent evolution of super black Plumage near bright color in 15 bird families
The Journal of Experimental Biology, 2019Co-Authors: Dakota E. Mccoy, Richard O. PrumAbstract:ABSTRACT We examined extremely low-reflectance, velvety black Plumage patches in 32 bird species from 15 families and five orders and compared them with 22 closely related control species with normal black Plumage. We used scanning electron microscopy to investigate microscopic feather anatomy, and applied spectrophotometry and hyperspectral imaging to measure Plumage reflectance. Super black Plumages are significantly darker and have more broadband low reflectance than normal black Plumages, and they have evolved convergently in 15 avian families. Super black feather barbules quantitatively differ in microstructure from normal black feathers. Microstructural variation is significantly correlated with reflectance: tightly packed, strap-shaped barbules have lower reflectance. We assigned these super black feathers to five heuristic classes of microstructure, each of which has evolved multiple times independently. All classes have minimal exposed horizontal surface area and 3D micrometer-scale cavities greater in width and depth than wavelengths of light. In many species, barbule morphology varied between the super black exposed tip of a feather and its (i) concealed base or (ii) iridescently colored spot. We propose that super black Plumages reduce reflectance, and flatten reflectance spectra, through multiple light scattering between the vertically oriented surfaces of microscale cavities, contributing to near-complete absorption of light by melanin. All super black Plumage patches identified occur adjacent to brilliant colored patches. Super black Plumage lacks all white specular reflections (reference points used to calibrate color perception), thus exaggerating the perceived brightness of nearby colors. We hypothesize that this sensory bias is an unavoidable by-product of color correction in variable light environments.
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Structural absorption by barbule microstructures of super black bird of paradise feathers
Nature communications, 2018Co-Authors: Dakota E. Mccoy, Teresa J. Feo, Todd Alan Harvey, Richard O. PrumAbstract:Many studies have shown how pigments and internal nanostructures generate color in nature. External surface structures can also influence appearance, such as by causing multiple scattering of light (structural absorption) to produce a velvety, super black appearance. Here we show that feathers from five species of birds of paradise (Aves: Paradisaeidae) structurally absorb incident light to produce extremely low-reflectance, super black Plumages. Directional reflectance of these feathers (0.05-0.31%) approaches that of man-made ultra-absorbent materials. SEM, nano-CT, and ray-tracing simulations show that super black feathers have titled arrays of highly modified barbules, which cause more multiple scattering, resulting in more structural absorption, than normal black feathers. Super black feathers have an extreme directional reflectance bias and appear darkest when viewed from the distal direction. We hypothesize that structurally absorbing, super black Plumage evolved through sensory bias to enhance the perceived brilliance of adjacent color patches during courtship display.
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Molecular diversity, metabolic transformation, and evolution of carotenoid feather pigments in cotingas (Aves: Cotingidae)
Journal of Comparative Physiology B, 2012Co-Authors: Richard O. Prum, Mary Caswell Stoddard, Amy M. Lafountain, Julien Berro, Harry A. FrankAbstract:Carotenoid pigments were extracted from 29 feather patches from 25 species of cotingas (Cotingidae) representing all lineages of the family with carotenoid Plumage coloration. Using high-performance liquid chromatography (HPLC), mass spectrometry, chemical analysis, and ^1H-NMR, 16 different carotenoid molecules were documented in the Plumages of the cotinga family. These included common dietary xanthophylls (lutein and zeaxanthin), canary xanthophylls A and B, four well known and broadly distributed avian ketocarotenoids (canthaxanthin, astaxanthin, α-doradexanthin, and adonixanthin), rhodoxanthin, and seven 4-methoxy-ketocarotenoids. Methoxy-ketocarotenoids were found in 12 species within seven cotinga genera, including a new, previously undescribed molecule isolated from the Andean Cock-of-the-Rock Rupicola peruviana, 3′-hydroxy-3-methoxy-β,β-carotene-4-one, which we name rupicolin. The diversity of cotinga Plumage carotenoid pigments is hypothesized to be derived via four metabolic pathways from lutein, zeaxanthin, β-cryptoxanthin, and β-carotene. All metabolic transformations within the four pathways can be described by six or seven different enzymatic reactions. Three of these reactions are shared among three precursor pathways and are responsible for eight different metabolically derived carotenoid molecules. The function of cotinga Plumage carotenoid diversity was analyzed with reflectance spectrophotometry of Plumage patches and a tetrahedral model of avian color visual perception. The evolutionary history of the origin of this diversity is analyzed phylogenetically. The color space analyses document that the evolutionarily derived metabolic modifications of dietary xanthophylls have resulted in the creation of distinctive orange-red and purple visual colors.
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how colorful are birds evolution of the avian Plumage color gamut
Behavioral Ecology, 2011Co-Authors: Mary Caswell Stoddard, Richard O. PrumAbstract:The avian Plumage color gamut is the complete range of Plumage colors, as seen by birds themselves. We used a tetrahedral avian color stimulus space to estimate the avian Plumage color gamut from a taxonomically diverse sample of 965 Plumage patches from 111 avian species. Our sample represented all known types of Plumage coloration mechanisms. The diversity of avian Plumage colors occupies only a portion (26–30%, using violet-sensitive and ultraviolet-sensitive models, respectively) of the total available avian color space, which represents all colors birds can theoretically see and discriminate. For comparison, we also analyzed 2350 plant colors, including an expansive set of flowers. Bird Plumages have evolved away from brown bark and green leaf backgrounds and have achieved some striking colors unattainable by flowers. Feather colors form discrete hue ‘‘continents,’’ leaving vast regions of avian color space unoccupied. We explore several possibilities for these unoccupied hue regions. Some Plumage colors may be difficult or impossible to make (constrained by physiological and physical mechanisms), whereas others may be disadvantageous or unattractive (constrained by natural and sexual selection). The Plumage gamut of early lineages of living birds was probably small and dominated by melanin-based colors. Over evolutionary time, novel coloration mechanisms allowed Plumages to colonize unexplored regions of color space. Pigmentary innovations evolved to broaden the gamut of possible communication signals. Furthermore, the independent origins of structural coloration in many lineages enabled evolutionary expansions into places unreachable by pigmentary mechanisms alone. Key words: bird vision, flower, gamut, morphospace, Plumage, structural color, tetrahedral color space. [Behav Ecol]
Geoffrey E. Hill - One of the best experts on this subject based on the ideXlab platform.
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effect of prenatal and natal administration of testosterone on production of structurally based Plumage coloration
Physiological and Biochemical Zoology, 2013Co-Authors: Lynn Siefferman, Mark Liu, Kristen J Navara, Mary T Mendonca, Geoffrey E. HillAbstract:AbstractTestosterone has been implicated as a developmental mechanism involved in the organization and expression of sexually dimorphic traits, such as Plumage coloration, in birds. Although research findings relating testosterone levels to Plumage expression is equivocal, few studies have investigated how testosterone may influence the expression of structurally based Plumage coloration. Here, we use experimental and correlational evidence to test the hypothesis that testosterone influences the development and maintenance of structurally based Plumage coloration in a wild-breeding population of eastern bluebirds (Sialia sialis). First, we experimentally manipulated yolk testosterone and measured the effect on the development of Plumage coloration of nestlings. Second, we implanted juvenile bluebirds with testosterone and measured the effect on nestling growth, body condition, and Plumage coloration of nestlings. Third, we measured covariation between circulating testosterone and Plumage coloration of bre...
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delayed Plumage maturation and delayed reproductive investment in birds
Biological Reviews, 2012Co-Authors: Gerard L Hawkins, Geoffrey E. Hill, Austin MercadanteAbstract:Delayed Plumage maturation is the delayed acquisition of a definitive colour and pattern of Plumage until after the first potential breeding period in birds. Here we provide a comprehensive overview of the numerous studies of delayed Plumage maturation and a revised theoretical framework for understanding the function of delayed Plumage maturation in all birds. We first distinguish between hypotheses that delayed Plumage maturation is attributable to a moult constraint with no adaptive function and hypotheses that propose that delayed Plumage maturation is a component of an adaptive life-history strategy associated with delayed reproductive investment. We then recognize three potential benefits of delayed Plumage maturation: crypsis, mimicry and status signaling. Evidence suggests that delayed Plumage maturation is not a consequence of developmental constraints and instead represents a strategy to maximize reproductive success in circumstances where young adults cannot effectively compete with older adults for limited resources, particularly breeding opportunities. A multi-factorial explanation that takes into account lifespan and the degree of competition for limited breeding resources and that combines the benefits of an inconspicuous appearance with the benefits of honest signaling of reduced competitiveness provides a general explanation for the function of delayed Plumage maturation in most bird species. Delayed Plumage maturation should be viewed as a component of alternative reproductive strategies that can include delay in both Plumage and sexual development. Such strategies are frequently facultative, with individuals breeding prior to the acquisition of definitive Plumages when conditions are favourable. Presumably, the benefits of delayed Plumage maturation ultimately enhance lifetime reproductive success, and studying delayed Plumage maturation within the context of lifetime reproductive success should be a goal of future studies.
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Carotenoid-based Plumage coloration predicts resistance to a novel parasite in the house finch
Naturwissenschaften, 2005Co-Authors: Geoffrey E. Hill, Kristy L. FarmerAbstract:The Hamilton-Zuk hypothesis proposes that the bright colours displayed by many species of birds serve as signals of individual resistance to parasites. Despite the popularity of this hypothesis, only one previous study has tested whether Plumage coloration predicts how individuals respond to a disease challenge. We inoculated 24 male house finches ( Carpodacus mexicanus ) of variable Plumage hue with a novel bacterial pathogen, Mycoplasma gallicepticum (MG). We found no relationship between Plumage hue and time to first symptoms following inoculation, but we found a significant negative relationship between Plumage hue and clearance of disease: males with redder Plumage cleared MG infection significantly better than did males with yellower Plumage. The hue of carotenoid-based Plumage coloration has been shown to be a primary criterion in female mate choice in the house finch. These observations suggest that one benefit to females for choosing redder males is obtaining mates with better resistance to parasites.
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structural and melanin coloration indicate parental effort and reproductive success in male eastern bluebirds
Behavioral Ecology, 2003Co-Authors: Ly Siefferma, Geoffrey E. HillAbstract:Male eastern bluebirds (Sialia sialis) have two types of ornamental Plumage coloration: a brilliant blue-ultraviolet head, back, and wings, and a patch of chestnut breast feathers. The blue-UV coloration is produced from feather microstructure, whereas the chestnut coloration is produced by a combination of pheaomelanin and eumelanin pigments deposited in feathers. We tested the hypothesis that Plumage coloration reflects male quality in eastern bluebirds, a socially monogamous, sexually dichromatic bird. We investigated whether male ornamentation correlates with mate quality and parental effort. We quantified three aspects of male ornament coloration: (1) size of the patch of chestnut breast feathers, (2) reflectance properties of the chestnut Plumage coloration, and (3) reflectance properties of the blue-ultraviolet Plumage coloration. We found that males with larger breast patches and brighter Plumage provisioned nestlings more often, fledged heavier offspring, and paired with females that nested earlier. Males with Plumage coloration that exhibit more ultraviolet hues fledged more offspring. These results suggest that Plumage coloration is a reliable indicator of male mate quality and reproductive success. Both melanin-based and structural-based Plumages appear to be honest signals of male quality and parental care that can be assessed by competitors or by potential mates. Copyright 2003.
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a red bird in a brown bag the function and evolution of colorful Plumage in the house finch
2002Co-Authors: Geoffrey E. HillAbstract:Part 1: Prelude 1. Darwinism and Wallacism: A Brief Account of the Long History of the Study of Plumage Coloration 2. A Red Bird in a Brown Bag: An Introduction to the House Finch 3. In the Eye of the Beholder: Color Vision and the Quantification of Colour Part 2: The Proximate Control and Function of Red Plumage 4. You Are What You Eat: Plumage Pigments and Carotenoid Physiology 5. A Matter of Condition: The Effect of Environment on Plumage Coloration 6. Darwin Vindicated: Female Choice and Sexual Selection in the House Finch 7. Fine Fathers and Good Genes: The Direct and Indirect benefits of female choice 8. Studs, Duds, and Studly Duds: Plumage Coloration, Hormones, and Dominance 9. The Feeling's Mutual: Female Plumage Coloration and Male Mate Choice Part 3: Biogeography and the Evolution of Colorful Plumage 10. From the Halls of Montezuma, to the Shores of Tripoli (New York): Populations, Subspecies, and Geographic Variation in Ornamental Coloration 11. Why Red?: The Evolution of Color Display Epilogue Glossary
Mary Caswell Stoddard - One of the best experts on this subject based on the ideXlab platform.
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Molecular diversity, metabolic transformation, and evolution of carotenoid feather pigments in cotingas (Aves: Cotingidae)
Journal of Comparative Physiology B, 2012Co-Authors: Richard O. Prum, Mary Caswell Stoddard, Amy M. Lafountain, Julien Berro, Harry A. FrankAbstract:Carotenoid pigments were extracted from 29 feather patches from 25 species of cotingas (Cotingidae) representing all lineages of the family with carotenoid Plumage coloration. Using high-performance liquid chromatography (HPLC), mass spectrometry, chemical analysis, and ^1H-NMR, 16 different carotenoid molecules were documented in the Plumages of the cotinga family. These included common dietary xanthophylls (lutein and zeaxanthin), canary xanthophylls A and B, four well known and broadly distributed avian ketocarotenoids (canthaxanthin, astaxanthin, α-doradexanthin, and adonixanthin), rhodoxanthin, and seven 4-methoxy-ketocarotenoids. Methoxy-ketocarotenoids were found in 12 species within seven cotinga genera, including a new, previously undescribed molecule isolated from the Andean Cock-of-the-Rock Rupicola peruviana, 3′-hydroxy-3-methoxy-β,β-carotene-4-one, which we name rupicolin. The diversity of cotinga Plumage carotenoid pigments is hypothesized to be derived via four metabolic pathways from lutein, zeaxanthin, β-cryptoxanthin, and β-carotene. All metabolic transformations within the four pathways can be described by six or seven different enzymatic reactions. Three of these reactions are shared among three precursor pathways and are responsible for eight different metabolically derived carotenoid molecules. The function of cotinga Plumage carotenoid diversity was analyzed with reflectance spectrophotometry of Plumage patches and a tetrahedral model of avian color visual perception. The evolutionary history of the origin of this diversity is analyzed phylogenetically. The color space analyses document that the evolutionarily derived metabolic modifications of dietary xanthophylls have resulted in the creation of distinctive orange-red and purple visual colors.
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how colorful are birds evolution of the avian Plumage color gamut
Behavioral Ecology, 2011Co-Authors: Mary Caswell Stoddard, Richard O. PrumAbstract:The avian Plumage color gamut is the complete range of Plumage colors, as seen by birds themselves. We used a tetrahedral avian color stimulus space to estimate the avian Plumage color gamut from a taxonomically diverse sample of 965 Plumage patches from 111 avian species. Our sample represented all known types of Plumage coloration mechanisms. The diversity of avian Plumage colors occupies only a portion (26–30%, using violet-sensitive and ultraviolet-sensitive models, respectively) of the total available avian color space, which represents all colors birds can theoretically see and discriminate. For comparison, we also analyzed 2350 plant colors, including an expansive set of flowers. Bird Plumages have evolved away from brown bark and green leaf backgrounds and have achieved some striking colors unattainable by flowers. Feather colors form discrete hue ‘‘continents,’’ leaving vast regions of avian color space unoccupied. We explore several possibilities for these unoccupied hue regions. Some Plumage colors may be difficult or impossible to make (constrained by physiological and physical mechanisms), whereas others may be disadvantageous or unattractive (constrained by natural and sexual selection). The Plumage gamut of early lineages of living birds was probably small and dominated by melanin-based colors. Over evolutionary time, novel coloration mechanisms allowed Plumages to colonize unexplored regions of color space. Pigmentary innovations evolved to broaden the gamut of possible communication signals. Furthermore, the independent origins of structural coloration in many lineages enabled evolutionary expansions into places unreachable by pigmentary mechanisms alone. Key words: bird vision, flower, gamut, morphospace, Plumage, structural color, tetrahedral color space. [Behav Ecol]
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how colorful are birds evolution of the avian Plumage color gamut
Behavioral Ecology, 2011Co-Authors: Mary Caswell Stoddard, Richard O. PrumAbstract:The avian Plumage color gamut is the complete range of Plumage colors, as seen by birds themselves. We used a tetrahedral avian color stimulus space to estimate the avian Plumage color gamut from a taxonomically diverse sample of 965 Plumage patches from 111 avian species. Our sample represented all known types of Plumage coloration mechanisms. The diversity of avian Plumage colors occupies only a portion (26--30%, using violet-sensitive and ultraviolet-sensitive models, respectively) of the total available avian color space, which represents all colors birds can theoretically see and discriminate. For comparison, we also analyzed 2350 plant colors, including an expansive set of flowers. Bird Plumages have evolved away from brown bark and green leaf backgrounds and have achieved some striking colors unattainable by flowers. Feather colors form discrete hue "continents," leaving vast regions of avian color space unoccupied. We explore several possibilities for these unoccupied hue regions. Some Plumage colors may be difficult or impossible to make (constrained by physiological and physical mechanisms), whereas others may be disadvantageous or unattractive (constrained by natural and sexual selection). The Plumage gamut of early lineages of living birds was probably small and dominated by melanin-based colors. Over evolutionary time, novel coloration mechanisms allowed Plumages to colonize unexplored regions of color space. Pigmentary innovations evolved to broaden the gamut of possible communication signals. Furthermore, the independent origins of structural coloration in many lineages enabled evolutionary expansions into places unreachable by pigmentary mechanisms alone. Copyright 2011, Oxford University Press.
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evolution of avian Plumage color in a tetrahedral color space a phylogenetic analysis of new world buntings
The American Naturalist, 2008Co-Authors: Mary Caswell Stoddard, Richard O. PrumAbstract:Abstract: We use a tetrahedral color space to describe and analyze male Plumage color variation and evolution in a clade of New World buntings—Cyanocompsa and Passerina (Aves: Cardinalidae). The Goldsmith color space models the relative stimulation of the four retinal cones, using the integrals of the product of Plumage reflectance spectra and cone sensitivity functions. A color is represented as a vector defined by the relative stimulation of the four cone types—ultraviolet, blue, green, and red. Color vectors are plotted in a tetrahedral, or quaternary, plot with the achromatic point at the origin and the ultraviolet/violet channel along the Z‐axis. Each color vector is specified by the spherical coordinates θ, φ, and r. Hue is given by the angles θ and φ. Chroma is given by the magnitude of r, the distance from the achromatic origin. Color vectors of all distinct patches in a Plumage characterize the Plumage color phenotype. We describe the variation in color space occupancy of male bunting Plumages, u...
Dakota E. Mccoy - One of the best experts on this subject based on the ideXlab platform.
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microstructures amplify carotenoid Plumage signals in tanagers
Scientific Reports, 2021Co-Authors: Dakota E. Mccoy, Allison J Shultz, Charles Vidoudez, Emma Van Der Heide, Sunia A Trauger, Jacqueline E Dall, David HaigAbstract:Brilliantly-colored birds are a model system for research into evolution and sexual selection. Red, orange, and yellow carotenoid-colored Plumages have been considered honest signals of condition; however, sex differences in feather pigments and microstructures are not well understood. Here, we show that microstructures, rather than carotenoid pigments, seem to be a major driver of male–female color differences in the social, sexually-dimorphic tanager genus Ramphocelus. We comprehensively quantified feather (i) color (using spectrophotometry), (ii) pigments (using liquid chromatography–mass spectrometry (LC–MS)), and (iii) microstructures (using scanning electron microscopy (SEM) and finite-difference time-domain (FDTD) optical modeling). Males have significantly more saturated color patches than females. However, our exploratory analysis of pigments suggested that males and females have concordant carotenoid pigment profiles across all species (MCMCglmm model, female:male ratio = 0.95). Male, but not female, feathers have elaborate microstructures which amplify color appearance. Oblong, expanded feather barbs in males enhance color saturation (for the same amount of pigment) by increasing the transmission of optical power through the feather. Dihedral barbules (vertically-angled, strap-shaped barbules) in males reduce total reflectance to generate “super black” and “velvet red” Plumage. Melanin in females explains some, but not all, of the male–female Plumage differences. Our results suggest that a widely cited index of honesty, carotenoid pigments, cannot fully explain male appearance. We propose that males are selected to evolve amplifiers—in this case, microstructures that enhance appearance—that are not necessarily themselves linked to quality.
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microstructures amplify carotenoid Plumage signals in colorful tanagers
bioRxiv, 2020Co-Authors: Dakota E. Mccoy, Allison J Shultz, Charles Vidoudez, Emma Van Der Heide, Sunia A Trauger, David HaigAbstract:Red, orange, and yellow carotenoid-colored Plumages have been considered honest signals of condition. We comprehensively quantified carotenoid signals in the social, sexually-dimorphic tanager genus Ramphocelus using scanning electron microscopy (SEM), finite-difference time-domain (FDTD) optical modeling, liquid chromatography-mass spectrometry (LC-MS), and spectrophotometry. Despite males having significantly more saturated color patches, males and females within a species have equivalent amounts and types of carotenoids. Male, but not female, feathers have elaborate microstructures which amplify color appearance. Expanded barbs enhance color saturation (for the same amount of pigment) by increasing the transmission of optical power through the feather. Dihedral barbules (vertically-angled, strap-shaped barbules) reduce total reflectance to generate "super black" Plumage, an optical illusion to enhance nearby color. Dihedral barbules paired with red carotenoid pigment produce "velvet red" Plumage. Together, our results suggest that a widely cited index of honesty--carotenoid pigments--cannot fully explain male appearance. We propose that males are selected to evolve amplifiers of honest signals--in this case, microstructures that enhance appearance-- that are not necessarily themselves linked to quality.
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convergent evolution of super black Plumage near bright color in 15 bird families
The Journal of Experimental Biology, 2019Co-Authors: Dakota E. Mccoy, Richard O. PrumAbstract:ABSTRACT We examined extremely low-reflectance, velvety black Plumage patches in 32 bird species from 15 families and five orders and compared them with 22 closely related control species with normal black Plumage. We used scanning electron microscopy to investigate microscopic feather anatomy, and applied spectrophotometry and hyperspectral imaging to measure Plumage reflectance. Super black Plumages are significantly darker and have more broadband low reflectance than normal black Plumages, and they have evolved convergently in 15 avian families. Super black feather barbules quantitatively differ in microstructure from normal black feathers. Microstructural variation is significantly correlated with reflectance: tightly packed, strap-shaped barbules have lower reflectance. We assigned these super black feathers to five heuristic classes of microstructure, each of which has evolved multiple times independently. All classes have minimal exposed horizontal surface area and 3D micrometer-scale cavities greater in width and depth than wavelengths of light. In many species, barbule morphology varied between the super black exposed tip of a feather and its (i) concealed base or (ii) iridescently colored spot. We propose that super black Plumages reduce reflectance, and flatten reflectance spectra, through multiple light scattering between the vertically oriented surfaces of microscale cavities, contributing to near-complete absorption of light by melanin. All super black Plumage patches identified occur adjacent to brilliant colored patches. Super black Plumage lacks all white specular reflections (reference points used to calibrate color perception), thus exaggerating the perceived brightness of nearby colors. We hypothesize that this sensory bias is an unavoidable by-product of color correction in variable light environments.
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Structural absorption by barbule microstructures of super black bird of paradise feathers
Nature communications, 2018Co-Authors: Dakota E. Mccoy, Teresa J. Feo, Todd Alan Harvey, Richard O. PrumAbstract:Many studies have shown how pigments and internal nanostructures generate color in nature. External surface structures can also influence appearance, such as by causing multiple scattering of light (structural absorption) to produce a velvety, super black appearance. Here we show that feathers from five species of birds of paradise (Aves: Paradisaeidae) structurally absorb incident light to produce extremely low-reflectance, super black Plumages. Directional reflectance of these feathers (0.05-0.31%) approaches that of man-made ultra-absorbent materials. SEM, nano-CT, and ray-tracing simulations show that super black feathers have titled arrays of highly modified barbules, which cause more multiple scattering, resulting in more structural absorption, than normal black feathers. Super black feathers have an extreme directional reflectance bias and appear darkest when viewed from the distal direction. We hypothesize that structurally absorbing, super black Plumage evolved through sensory bias to enhance the perceived brilliance of adjacent color patches during courtship display.
Paulo Gama Mota - One of the best experts on this subject based on the ideXlab platform.
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colourful male european serins serinus serinus are more careful with their Plumage
Ibis, 2015Co-Authors: Paulo Gama Mota, Ana V LeitaoAbstract:Ornamental traits typically advertise individual condition and can be costly to maintain. Plumage maintenance behaviour can increase Plumage quality and positively influence female mate preference. We investigated this prediction by performing female mate-choice trials and measuring male Plumage maintenance behaviour in the European Serin Serinus serinus. More colourful males spent more time in Plumage maintenance than less colourful males, but this was not correlated with body condition or ectoparasite load. Females preferred more colourful males, although this was not influenced by male Plumage maintenance. Our findings highlight the fact that investment in Plumage maintenance depends on individual coloration and this may reinforce the honesty of ornamental Plumage and convey positive information for mate choice.
