Nature provides a multitude of nanostructures that have been finely tuned by natural selection and produce structural colourations that play a role in many biological functions such as mating, signalling or camouflage. A recurring design that is found both in the animal and plant kingdoms is the helicoidal structure, i.e. a multi-layer structure where adjacent layers rotate along a helical screw. Examples of such structures have been found in different plant tissues, in algae, and also in fishes and insects. This review focuses on the structural colour produced by these natural structures, discusses their common morphology and connects their mor- phological characteristics to their optical properties. We show that their biological importance suggests convergent evolution of an optimised, left-handed multi-layered structure.

This article originally appeared in Materials Today: Proceedings 1, Supplement, 2014, Pages 177-185