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Published online: 6 February 2008 | doi:10.1038/nchina.2008.30

Colour structures: Beetle blue

Tim Reid

Introduction

© (2008) APS

Colouration in nature, particularly in insects such as beetles and butterflies, can inspire the development of optical structures for camouflage and signal communication technology. A recent investigation by Xiaohan Liu and Jian Zi at Fudan University in Shanghai and co-workers¹ has shown how tiny three-dimensional surface structures create iridescence on the wing casings of the coleoptera beetle.

Male coleoptera beetles were analysed under electron microscopes. The researchers found that the wing-casing surfaces comprise a hexagonal array of round pits like a honeycomb. Ridges of the hexagonal frame and the base of each pit are green and cyan in colour, respectively (pictured), whereas the inclined sides are dull blue.

When viewed from above with the naked eye, the mixture of these colours gives the wing casings a bluish green colour. Seen from shallower angles, however, the colour of the inclined sides dominates, which gives the wing casings a deeper blue iridescence.

Similar structural colourings have been observed in wings of tiger beetles and butterflies, but coleoptera beetle wings can reflect incident light in a much wider range of viewing angles. This feature may inspire designs of novel optical structures.

The authors of this work are from:
Surface Physics Laboratory and Department of Physics, Fudan University, Shanghai, China; T-Life Research Centre, Fudan University, Shanghai, China; College of Life Sciences, Chongqing Normal University, Chongqing, China.

Reference

1. Liu, F. et al. Inconspicuous structural coloration in the elytra of beetles Chlorophila obscuripennis (Coleoptera). Phys. Rev. E 77, 012901 (2008). | Article |