Natural waveguides on Hoplia argentea elytra

Abstract

Light waveguides are structures with a role in receiving and channeling light and filtering certain wavelengths of the electromagnetic spectrum [1]. That's how it comes to light capturing and local reinforcement of its intensity, which can be further utilized for various purposes (e.g conducting light to pigments in the eye, forming structural coloration, etc.) [2]. Based on their geometric structure waveguides can be planar or linear (banded or fibrous) [3]. Microstructures with a waveguide role have been studied a lot in the living world [4]. Structures with a function of optical waveguides have also been discovered in insects. They can be found on antennae, in complex eyes, on wing scales and other parts of the body [5], and can work as integral part of light or IR receptors, thermoregulatory systems, or can play an important role in the formation of structural coloration [6]. Here we present cuticular structures on beetle elytra (Insecta: Coleoptera) that produce structural coloration thanks to morphology and function of light waveguides. Hoplia argentea from family Rutelidae was used as a model organism. We found out that individuals of this species posses linear type of waveguides on its front hardened wings, which are responsible for the production of structurally green coloration.