The Blue Morpho Butterfly; its color comes not from the pigments on its wings, but from the way the light refracts on the microstructures of its wings (see image below).
I really like the sound of plasmonic pixels. But let’s not forget the biomimetic method of structural color vs. chemicals and pigments. The Morpho butterfly is an example where the colors are not a matter of surface treatment but of the structure of the wings themselves. They refract light differently to create a colorful pattern, although the wing is really all the same “color.”
phys.org, Jun 2016
Here’s a book about where color came from:
The Color Revolution, Regina Lee Blaszczyk, MIT Press 2012
And here’s my review