[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-149239-105":59,"doc-detail-149239-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","structural-colouration-of-avian-skin-convergent-evolution-of-coherently-scattering-dermal-collagen-arrays","Structural colouration of avian skin - convergent evolution of coherently scattering dermal collagen arrays","","Structural colours of avian skin are investigated as a coherent-scattering mechanism rather than incoherent Rayleigh/Tyndall scattering. Using colour measurements, anatomical study, nanostructure imaging, and biophysical analysis across 31 bird species in 17 families, the work links reflectance peaks to quasi-ordered dermal collagen arrays. Two-dimensional Fourier analysis identifies spatial frequencies sized to generate ultraviolet–yellow hues, with one species showing exceptionally ordered hexagonal collagen patterns. A phylogenetic assessment indicates convergent evolution over 50 independent times among extant birds, with pigment–structure combinations explaining some saturated yellows and oranges.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":40,"@type":76,"position":81},"https://docshare.wps.com/document/research-report/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/structural-colouration-of-avian-skin-convergent-evolution-of-coherently-scattering-dermal-collagen-arrays/149239/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/structural-colouration-of-avian-skin-convergent-evolution-of-coherently-scattering-dermal-collagen-arrays/149239.png","ImageObject",300,407,{"name":92,"@type":93},"Đào","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-09-14","2026-08-27",true,{"@type":102,"interactionType":103,"userInteractionCount":24},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What mechanism is proposed for structural colours in avian skin?","Question",{"text":112,"@type":113},"The study argues that ultraviolet–yellow structural colours are produced by coherent scattering, specifically constructive interference from coherently arranged dermal collagen fibre arrays.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How do the reflectance spectra relate to Rayleigh scattering predictions?",{"text":117,"@type":113},"The discrete peaks in reflectance spectra do not follow the inverse fourth power relationship expected from Rayleigh scattering, supporting a coherent-scattering origin.",{"name":119,"@type":110,"acceptedAnswer":120},"What role does two-dimensional Fourier analysis play in the results?",{"text":121,"@type":113},"Two-dimensional Fourier analysis of TEM images reveals a ring of peak spatial frequencies in refractive index variation, whose size matches the wavelengths needed to produce the observed structural colours.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},149239,1787797107,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":24,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":139,"language":140,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":67,"update_tm":129,"read_time":144},1374402968488,"https://ap-avatar.wpscdn.com/davatar_29158cc5080c5b710cf443261637dec0","The Journal of Experimental Biology 206, 2409-2429 2409  \n© 2003 The Company of Biologists Ltd doi:10.1242/jeb.00431  \nStructural colouration of avian skin: convergent evolution of coherently  \nscattering dermal collagen arrays  \nRichard O. Prum 1,* and Rodolfo Torres2  \n1Department of Ecology and Evolutionary Biology, and Natural History Museum, Dyche Hall, University of Kansas, Lawrence, KS 66045-7561, USA and 2Department of Mathematics, University of Kansas, Lawrence,  \nKS 66045-2142, USA  \n*Author for correspondence ([e-mail: prum@ku.edu](e-mail: prum@ku.edu))  \nAccepted 4 April 2003  \nSummary  \nStructural 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 colourproducing dermal collagen layer revealed quasi-ordered arrays of parallel collagen fibres. Two-dimensional (2-D) Fourier analysis of TEMs ofthe 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  \nthat 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) arenanostructurally 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.  \nKey words: structural colour, colour, collagen, integument, nanostructure, Fourier analysis, Aves.  \nIntroduction  \nThe colours of organisms are produced by molecular pigments or by optical interactions with biological nanostructures. The latter structural colours form an important part of the phenotype of many animals (Fox, 1976; Herring, 1994; Parker, 1999) and even some plants (Lee, 1997) . Although descriptions ofthe physical mechanisms of structural colour production are diverse and often redundant (Fox, 1976; Nassau, 1983; Parker, 1999; Srinivasarao, 1999), most mechanisms of structural colour production can be well understood as variations of light scattering at the interfaces of objects that differ in refractive index. (For a fascinating exception in insect cuticle, see Neville, 1975, 1993.)  \nAccordingly, structural colour production mechanisms can be classified as forms of either incoherent or coherent scattering (van de Hulst, 1981; Bohren and Huffman, 1983) .  \nIncoherent scattering occurs when individual light-scattering objects differentially scatter visible wavelengths (Fig. 1A) . Incoherent scattering models require that the light-scattering objects are spatially independent (i.e. randomly dis","cbCaiudKWdUOWaGN","https://ap.wps.com/l/cbCaiudKWdUOWaGN","pdf",1983627,21,"English","# Summary\n# Key findings\n## Coherent scattering mechanism\n## Collagen nanostructure and Fourier analysis\n# Introduction\n## Structural vs pigmentary colour production\n## Incoherent vs coherent scattering","[{\"question\":\"What mechanism is proposed for structural colours in avian skin?\",\"answer\":\"The study argues that ultraviolet–yellow structural colours are produced by coherent scattering, specifically constructive interference from coherently arranged dermal collagen fibre arrays.\"},{\"question\":\"How do the reflectance spectra relate to Rayleigh scattering predictions?\",\"answer\":\"The discrete peaks in reflectance spectra do not follow the inverse fourth power relationship expected from Rayleigh scattering, supporting a coherent-scattering origin.\"},{\"question\":\"What role does two-dimensional Fourier analysis play in the results?\",\"answer\":\"Two-dimensional Fourier analysis of TEM images reveals a ring of peak spatial frequencies in refractive index variation, whose size matches the wavelengths needed to produce the observed structural colours.\"}]","Structural colouration of avian skin - convergent evolution of coherently scattering dermal collagen arrays | PDF",53]