The compound eyes of insects consist of multiple units, called ommatidia. The units are covered by a thin layer of cuticle called the “facet.” Facets that are smooth and flat create a reflective surface (like a mirror) that flashes light from a source such as the sun. Reflective surfaces are not desirable in moths that fly at night and rest during the day. Reflection of light by the facets of the eyes might signal their location to predators.
Perhaps this is why the facets of the compound eyes of moths are not smooth and reflective, but covered with protuberances of the cuticle called “corneal nipples”. The corneal nipples reduce glare and reflection. These optical properties can be reproduced in synthetic films that are not smooth, but contain surfaces with synthetic nipples. These moth-eye films have a variety of uses including window coatings, camera lenses, cell phone displays and computer screens.
Most recently, moth-eye films are finding uses in solar cells. The films reduce the reflectance of the surface. Less light lost to reflectance translates into more light entering the solar cell, increasing its efficiency.
Insects have evolved many solutions to challenges posed by nature. By studying these insect adaptations, we can apply the insect solutions to our own technological challenges.