Structural colouration of avian skin: convergent evolution of coherently scattering dermal collagen arrays

Author:

Prum Richard O.1,Torres Rodolfo2

Affiliation:

1. Department of Ecology and Evolutionary Biology, and Natural History Museum, Dyche Hall, University of Kansas, Lawrence, KS 66045-7561,USA

2. Department of Mathematics, University of Kansas, Lawrence, KS 66045-2142,USA

Abstract

SUMMARYStructural colours of avian skin have long been hypothesized to be produced by incoherent (Rayleigh/Tyndall) scattering. We investigated the colour,anatomy, nanostructure and biophysics of structurally coloured skin,ramphotheca and podotheca from 31 species of birds from 17 families in 10 orders from across Aves. Integumentary structural colours of birds include ultraviolet, dark blue, light blue, green and yellow hues. The discrete peaks in reflectance spectra do not conform to the inverse fourth power relationship predicted by Rayleigh scattering. The dermis of structurally coloured skin consists of a thick (100–500 μm) layer of collagen that is usually underlain by a layer of melanin granules. Transmission electron micrographs(TEMs) of this colour-producing dermal collagen layer revealed quasi-ordered arrays of parallel collagen fibres. Two-dimensional (2-D) Fourier analysis of TEMs of the collagen arrays revealed a ring of peak spatial frequencies in the spatial variation in refractive index that are the appropriate size to make the observed ultraviolet–yellow colours by coherent scattering alone. One species, Philepitta castanea (Eurylaimidae), has exceptionally ordered, hexagonal arrays of collagen fibres that produce a hexagonal pattern of spatial frequency peaks in the power spectra. Ultraviolet, blue, green and yellow structural colours of avian skin are produced by coherent scattering(i.e. constructive interference) by arrays of collagen fibres in the dermis. Some yellow and orange skin colours are produced with a combination of structural and pigmentary mechanisms. These combined colours can have reflectance spectra with discrete peaks that are more saturated than hues produced by carotenoid pigments alone. Bluish facial skin from two species of Neotropical antbirds (Thamnophilidae) are nanostructurally too small to produce visible light by coherent scattering, and the colour production mechanism in these species remains unknown. Based on the phylogenetic distribution of structurally coloured skin in Aves, this mechanism of colour production has evolved convergently more than 50 independent times within extant birds.

Publisher

The Company of Biologists

Subject

Insect Science,Molecular Biology,Animal Science and Zoology,Aquatic Science,Physiology,Ecology, Evolution, Behavior and Systematics

Reference61 articles.

1. Auber, L. (1957). The distribution of structural colors and unusual pigments in the Class Aves. Ibis99,463-476.

2. Bagnara, J. T. (1998). Comparative anatomy and physiology of pigment cells in nonmammalian tissues. In The Pigmentary System – Physiology and Pathophysiology (ed. J. J. Nordlund, R. E. Boissy, V. J. Hearing, R. A. King and J. P. Ortonne), pp.9-40. Oxford: Oxford University Press.

3. Bagnara, J. T. and Hadley, M. E. (1973). Chromatophores and Color Change. New Jersey: Prentice Hall.

4. Bellairs, R., Harkness, M. L. and Harkness, R. D.(1975). The structure of the tapetum of the eye of the sheep. Cell Tissue Res.157,73-91.

5. Benedek, G. B. ( 1971). Theory of transparency of the eye. Appl. Optics10,459-473.

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