An insect’s eye inspires a new camera for smartphones

MALES of a species called Xenos peckii have an unusual eye for the ladies. X. peckii is a member of the Strepsiptera, a group of insects that parasitise other insects. Its victim of choice is the paper wasp, inside the abdomen of which it develops from larva to adult by eating its host from the inside. Females of the species are blind—there is, after all, little to see in their abode. But males have a pair of eyes (see picture) that are unique to the Strepsiptera, and vital for one brief and important task. When he matures, a male X. peckii must leave his host and find a mate quickly, because he will die within a few hours. A group of researchers working for the Fraunhofer Society, a German government research organisation, have now copied the way male X. peckii eyes work, and used the method as the basis of a new miniature camera for smartphones.

Many animals (human beings and octopuses are good examples), have eyes that use a single lens to focus light onto a sheet of receptor cells at the back of the eye, called a retina, to form an image. This is similar to the way that a digital camera’s lens focuses such an image onto a retina-like light-sensor made up of millions of individual detectors. Other creatures, though—insects among them—have compound eyes. These are composed of units called ommatidia. Each ommatidium consists of a tiny lens, called a facet, and a few receptor cells. The eye itself is a bulbous structure composed of many of these ommatidia arrayed together. Individual ommatidia detect points of light, which act as the pixels from which the creature’s brain weaves a complete image. Compound eyes generally have worse resolutions than single-lens eyes, but their shape provides a wider field of view, which is useful for spotting food and predators.