title: Orange reflection from a three-dimensional photonic crystal in the scales of the weevil Pachyrrhynchus congestus pavonius (Curculionidae).
abstract: The three-dimensional structure that causes the coloration of the tropical weevil Pachyrrhynchus congestus pavonius was studied, using a combination of electron microscopy, optical spectroscopy, and numerical modeling. The orange scales that cover the colored rings on the animal's body were opened, to display the structure responsible for the coloration. This structure is a three-dimensional photonic polycrystal, each grain of which showing a face-centered cubic symmetry. The measured lattice parameter and the observed filling fraction of this structure explain the dominant reflected wavelength in the reddish orange. The long-range disorder introduced by the grain boundaries explains the paradoxical observation that the reflectance, although generated by a photonic crystal, is insensitive to changes in the viewing angle.
authors.affiliation: Laboratoire de Physique du Solide, Facultés Universitaires Notre-Dame de la Paix, 61 rue de Bruxelles, B-5000 Namur, Belgium.
authors.forename: Victoria
authors.initials: V
authors.lastname: Welch
authors.forename: Virginie
authors.initials: V
authors.lastname: Lousse
authors.forename: Olivier
authors.initials: O
authors.lastname: Deparis
authors.forename: Andrew
authors.initials: A
authors.lastname: Parker
authors.forename: Jean Pol
authors.initials: JP
authors.lastname: Vigneron
mesh_terms: D000818:Animals; D001703:Biophysics / Q000379:methods; D003198:Computer Simulation; D003460:Crystallization; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D015233:Models, Statistical; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D017785:Photons; D048889:Weevils / Q000378:metabolism*