Nature's raincoat in monochrome

In Nature, keeping dry is sometimes a matter of life and death. A flying insect can literally drown if engulfed by falling raindrops. To avoid this, the wings of a Morpho butterfly are precisely sculpted, with highly ordered micro- and nano- structures on their scales, to trap an air layer and repel water. Droplets of water will ball up on the wings into perfect spheres and will roll off even with the tiniest flick. The highly-ordered nanostructures also give the wings of a morpho butterfly a brilliant blue colour, which does not fade with time unlike typical colour pigments