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dc.contributor.authorPrum, Richard O.
dc.contributor.authorCole, Jeffrey A.
dc.contributor.authorTorres, Rodolfo H.
dc.date.accessioned2007-05-15T14:58:47Z
dc.date.available2007-05-15T14:58:47Z
dc.date.issued2004-10
dc.identifier.citationPrum, RO; Cole, JA; Torres, RH. Blue integumentary structural colours in dragonflies (Odonata) are not produced by incoherent Tyndall scattering. JOURNAL OF EXPERIMENTAL BIOLOGY. October 2004. 207(22) : 3999-4009
dc.identifier.otherhttp://jeb.biologists.org/
dc.identifier.urihttp://hdl.handle.net/1808/1601
dc.description.abstractFor nearly 80 years, the non-iridescent, blue, integumentary structural colours of dragonflies and damselflies (Odonata) have been attributed to incoherent Tyndall or Rayleigh scattering. We investigated the production of the integumentary structural colours of a damselfly - the familiar bluet, Enallagma civile (Coenagrionidae) - and a dragonfly - the common green darner, Anax junius (Aeshnidae) - using fibre optic spectrophotometry and transmission electron microscopy (TEM). The reflectance spectra of both species showed discrete reflectance peaks of similar to30% reflectance at 475 and 460 nm, respectively. These structural colours are produced by light scattering from closely packed arrays of spheres in the endoplasmic reticulum of box-shaped epidermal pigment cells underlying the cuticle. The observed reflectance spectra do not conform to the inverse fourth power relationship predicted for Tyndall/Rayleigh scattering. Two-dimensional (2-D) Fourier analysis of the TEM images of the colour-producing arrays reveals ring-shaped distributions of Fourier power at intermediate spatial frequencies, documenting a quasiordered nanostructure. The nanostructured Fourier power spectra falsify the assumption of spatial independence of scatterers that is required for incoherent scattering. Radial averages of the Fourier power spectrum indicate that the spheres are substantially nanostructured at the appropriate spatial scale to produce visible colours by coherent scattering. However, the spatial periodicity of the arrays is apparently too large to produce the observed colour by coherent scattering. The nanospheres could have expanded substantially (similar to50%) during preparation for TEM. Alternatively, coherent light scattering could be occurring both from the surfaces and from structures at the centre of the spheres. These arrays of colour-producing spheres within pigment cells have convergently evolved at least 11-14 times independently within the Odonata. Structural colouration from arrays in living cells has also fostered the convergent evolution of temperature-dependent colour change in numerous odonate lineages.
dc.language.isoen_US
dc.publisherCOMPANY OF BIOLOGISTS LTD
dc.subjectstructural colour
dc.subjectdragonfly
dc.subjectdamselfly
dc.subjectcoherent scattering
dc.subjectTyndall scattering
dc.subjectRayleigh scattering
dc.subjectpigment cells
dc.subjectEnallagma civile
dc.subjectAnax junius
dc.titleBlue integumentary structural colours in dragonflies (Odonata) are not produced by incoherent Tyndall scattering
dc.typeArticle
dc.rights.accessrightsopenAccess


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