Dresden 2017 – wissenschaftliches Programm
CPP 10.1: Vortrag
Montag, 20. März 2017, 15:00–15:15, ZEU 114
Extreme refractive index wing scale beads cause the bright colors of pierid butterflies — •Bodo Wilts1, Bas Wijnen2, Ullrich Steiner1, and Doekele Stavenga2 — 1Adolphe Merkle Institute, University of Fribourg, Switzerland — 2University of Groningen, Groningen, the Netherlands
Butterflies feature strong, vivid colours due to photonic structures on their surface. Butterflies of the family Pieridae are brightly colored, ranging from white to red, caused by various pterin pigments concentrated in scattering spheroidal beads in the wing scales. Given the sparsity of the beads in the wing scales, the high brightness suggests a scattering strength of the beads that significantly surpasses that of typical cuticular chitin beads with the aereal density found in the wing scales. To elucidate this apparent contradiction, we have analyzed the optical signature of the pierids* highly saturated pigmentary colors by using Jamin-Lebedeff interference microscopy combined with Kramers-Kronig theory and light scattering modeling. We show that extreme pterin pigment concentrations cause a very high refractive index of the beads with values above 2 across the visible wavelength range, thus creating one of the most highly light scattering media thus far discovered in the animal kingdom.