Iridescent structurally based coloration of eyespots correlates with mating success in the peacock

Loyau, Adeline; Gomez, Doris; Moureau, Benoît; Théry, Marc; Hart, Nathan S.; Jalme, Michel Saint; Bennett, Andrew T. D.; Sorci, Gabriele

doi:10.1093/beheco/arm088

Cited by 103 publications

(82 citation statements)

References 65 publications

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“…They create the metallic and polarized reflections of, for example, the skin of cephalopods [9] and fishes [11], the elytra of jewel beetles [12 -15], scarabs [16,17], and the breast feathers of birds of paradise [18]. Two-dimensional photonic crystals, that is, structures with periodicity in two dimensions, underlie the coloration of peacock feathers [19,20]. Three-dimensional photonic crystals have been found in the scales of many weevils and beetles [1,21 -24], but also in butterflies [25 -28].…”

Section: Introductionmentioning

confidence: 99%

Brilliant camouflage : photonic crystals in the diamond weevil, Entimus imperialis

et al. 2012

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The neotropical diamond weevil, Entimus imperialis, is marked by rows of brilliant spots on the overall black elytra. The spots are concave pits with intricate patterns of structural-coloured scales, consisting of large domains of three-dimensional photonic crystals that have a diamond-type structure. Reflectance spectra measured from individual scale domains perfectly match model spectra, calculated with anatomical data and finite-difference time-domain methods. The reflections of single domains are extremely directional (observed with a point source less than 58), but the special arrangement of the scales in the concave pits significantly broadens the angular distribution of the reflections. The resulting virtually angle-independent green coloration of the weevil closely approximates the colour of a foliaceous background. While the closedistance colourful shininess of E. imperialis may facilitate intersexual recognition, the diffuse green reflectance of the elytra when seen at long-distance provides cryptic camouflage.

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Section: Introductionmentioning

confidence: 99%

Brilliant camouflage : photonic crystals in the diamond weevil, Entimus imperialis

et al. 2012

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“…It is thus surprising that, despite numerous studies examining both the condition-dependence and sexual selection of structurally coloured traits in birds [7,[14][15][16][17][18], their developmental mechanisms are still largely unknown. Only recently has a hypothesis for the organization of non-iridescent spongy layers been proposed [19,20].…”

Section: Introductionmentioning

confidence: 99%

Nanostructural self-assembly of iridescent feather barbules through depletion attraction of melanosomes during keratinization

Maia

Macêdo

Shawkey

2011

J. R. Soc. Interface.

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Avian plumage colours are model traits in understanding the evolution of sexually selected ornamental traits. Paradoxically, iridescent structural colours, probably the most dazzling of these traits, remain the most poorly understood. Though some data suggest that expression of bright iridescent plumage colours produced by highly ordered arrays of melanosomes and keratin is condition-dependent, almost nothing is known of their ontogeny and thus of any developmental mechanisms that may be susceptible to perturbation. Here, we use light and electron microscopy to compare the ontogeny of iridescent male and non-iridescent female feathers in blue-black grassquits. Feather barbules of males contain a single layer of melanosomes bounded by a thin layer of keratin-producing blue iridescent colour, while those of females contain disorganized melanosomes and no outer layer. We found that nanostructural organization of male barbules occurs late in development, following death of the barbule cell, and is thus unlikely to be under direct cellular control, contrary to previous suggestions. Rather, organization appears to be caused by entropically driven self-assembly through depletion attraction forces that pin melanosomes to the edge of barbule cells and to one another. These forces are probably stronger in developing barbules of males than of females because their melanosomes are (i) larger, (ii) more densely packed, and (iii) more homogeneously distributed owing to the more consistent shape of barbules during keratinization. These data provide the first proposed developmental pathway for iridescent plumage colours, and suggest that any condition dependence of iridescent barbules is likely driven by factors other than direct metabolic cost.

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“…For example, in mallards, male bill colour signals immunocompetence [28]. Thus, females could use carotenoid-based signals to evaluate male genetic quality and may invest more in those advertising good genes for immune status or antioxidant system efficiency [44,71,72]. Third, it was demonstrated in mallards that male bill coloration, and particularly relative UV reflectance, is negatively correlated with sperm velocity [28].…”

Section: Discussionmentioning

confidence: 99%

“…Reflectance was calculated relative to a white standard and the three spectra obtained for each bird were averaged and summarized over 1 nm steps. From these spectrum measurements, we extracted hue, chroma, UV-chroma and brightness as response variables to assess variation in true coloration (see Loyau et al [44] for a full description of these colour variables). Computations were conducted with the AVICOL software [45].…”

Section: Methodsmentioning

confidence: 99%

Maternal investment of female mallards is influenced by male carotenoid-based coloration

et al. 2010

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The differential allocation hypothesis predicts that females modify their investment in a breeding attempt according to its reproductive value. One prediction of this hypothesis is that females will increase reproductive investment when mated to high-quality males. In birds, it was shown that females can modulate pre-hatch reproductive investment by manipulating egg and clutch sizes and/or the concentrations of egg internal compounds according to paternal attractiveness. However, the differential allocation of immune factors has seldom been considered, particularly with an experimental approach. The carotenoid-based ornaments can function as reliable signals of quality, indicating better immunity or ability to resist parasites. Thus, numerous studies show that females use the expression of carotenoid-based colour when choosing mates; but the influence of this paternal coloration on maternal investment decisions has seldom been considered and has only been experimentally studied with artificial manipulation of male coloration. Here, we used dietary carotenoid provisioning to manipulate male mallard (Anas platyrhynchos) bill coloration, a sexually selected trait, and followed female investment. We show that an increase of male bill coloration positively influenced egg mass and albumen lysozyme concentration. By contrast, yolk carotenoid concentration was not affected by paternal ornamentation. Maternal decisions highlighted in this study may influence chick survival and compel males to maintain carotenoid-based coloration from the mate-choice period until egg-laying has been finished.

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Iridescent structurally based coloration of eyespots correlates with mating success in the peacock

Cited by 103 publications

References 65 publications

Brilliant camouflage : photonic crystals in the diamond weevil, Entimus imperialis

Brilliant camouflage : photonic crystals in the diamond weevil, Entimus imperialis

Nanostructural self-assembly of iridescent feather barbules through depletion attraction of melanosomes during keratinization

Maternal investment of female mallards is influenced by male carotenoid-based coloration

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