Shiny wing scales cause spec(tac)ular camouflage of the angled sunbeam butterfly, Curetis acuta

Authors

  • Bodo D. Wilts,

    Corresponding author
    1. Computational Physics, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
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  • Primož Pirih,

    1. Department of Biology, Faculty of Biotechnical Sciences, University of Ljubljana, Ljubljana, Slovenia
    2. Department of Materials and Metallurgy, Faculty of Natural Sciences and Engineering, University of Ljubljana, Ljubljana, Slovenia
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  • Kentaro Arikawa,

    1. Laboratory of Neuroethology, Sokendai-Hayama (The Graduate University for Advanced Studies), Hayama, Japan
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  • Doekele G. Stavenga

    1. Computational Physics, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
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Abstract

The angled sunbeam butterfly, Curetis acuta (Lycaenidae), is a distinctly sexually dimorphic lycaenid butterfly from Asia. The dorsal wings of female and male butterflies have a similar pattern, with a large white area in the female and an orange area in the male, framed within brown–black margins. The ventral wings of both sexes are silvery white, which is caused by stacks of overlapping, non-pigmented, and specular-reflecting scales. With oblique illumination, the reflected light of the ventral wings is strongly polarized. We show that the silvery reflection facilitates camouflage in a shaded, foliaceous environment. The ecological function of the silvery reflection is presumably two-fold: for intraspecific signalling in flight, and for reducing predation risk at rest and during hibernation. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 279–289.

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