We all know that we shouldn’t make fun of people with glasses, but now it appears that bugs with bifocals deserve our respect too. Researchers from the University of Cincinnati (UC) have discovered that the larvae of the sunburst diving beetle (Thermonectus marmoratus) have bifocal eyes. As far as they are aware, this is the first known example of truly bifocal lenses in the animal kingdom. Previously, only prehistoric trilobites were suspected of having had bifocal vision. Besides being a big hairy deal in the bug world, this news could also have implications for human technology.
The larvae have two retinas and two distinct focal planes, in each of at least four of their eyes (the study concentrated on one set of two eyes). That means that each eye is processing two images, essentially acting as two eyes in one. Like humans with bifocal glasses, the larvae can switch between close-up and distance vision, although their system works much more efficiently than ours. In their version,the unfocused image from one lens is shifted away from the focused image from the other, which the scientists believe could improve their visual contrast. The insects use their bifocal vision mainly for stalking and catching prey, as there aren’t many tiny books or cars in their natural habitat.
At first the scientists doubted their findings, but confirmed them by actually looking the eyes of the larvae with a microscope, and by studying the refraction of a laser beam shone through the eyes.
The discovery was made in the lab of Elke K. Buschbeck, a UC associate professor of biology. “We’re hoping this discovery could hold implications for humans, pending possible future research in biomedical engineering,” she said. Fellow researcher Annette Stowasser added that the discovery could also have uses in imaging technology.
The research was recently published in the journal Current Biology.