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If you've stalked six-legged pests and been frustrated by how tricky it is to get the jump on them, here's why: you can't sneak up on insects. No matter which direction you're coming from, they can see you and take evasive action. Their bulging convex eyes, each containing thousands of mini-eyes, give bugs wraparound vision. In that capacity, human vision can't compete—but our eyes deliver a much deeper and more detailed picture of our surroundings. Today some researchers are striving to advance artificial visual technology by combining the best of both ways of seeing.
In an essay on the differences between human and animal vision, Jonathan T. Erichsen and J. Margaret Woodhouse of the Cardiff School of Optometry caution, "We must never make the mistake of thinking that only we see the world as it really is." The capacity for vision is common to almost all living creatures and despite adaptations for differing circumstances, eyesight helps animals—and people—recognize the necessities of life: food, danger, mates and shelter. In his 2004 book "In the Blink of an Eye," Oxford zoologist Andrew Parker argues that the evolution of complex eyes, which he describes as "the most dramatic event in the history of life," fast-tracked the evolution of species more than 540 million years ago.
When we focus our eyes on something and "see" it, the process feels instantaneous but is actually the outcome of a complex series of actions. As Macalester College explains it, when light enters our eyes, the cornea projects it onto the retina at the back of the eyeball. After the pattern is analysed by cells connected to the brain, the occipital lobe translates that information into images our conscious mind can interpret. Our forward-looking eyes excel at depth perception and discernment of details but are sensitive only to a narrow range of wavelengths, don't function well in low light and are useless for detecting predators approaching from behind.
In contrast to inset human eyes, the compound eyes of insects "bug" outward, allowing them to see in all directions simultaneously. Insects' eyes generally contain between 3,000 and 9,000 ommatidia, or optical units, although darting insects like dragonflies can have as many as 25,000 in each eye. The more ommatidia, the better the image resolution, but unlike human eyes, insects tend to perceive shapes and outlines rather than crisp details. Human eyes are unable to detect the shorter wavelengths of ultraviolet light but many insects, including bees, can. According to Australian bee expert Adrian Dyer, to attract bees, certain flowers have evolved patterns that are visible only to creatures with UV light vision.
Applications for Technology
After Adrian Dyer discovered that bees could be trained to solve visual problems, he realized that brain size isn't necessarily a reliable indicator of functional capability in animals. In 2008 he suggested that the miniature brains of insects might offer more useful insights into the development of artificial visual technology than the complex brains of primates. In May 2013, one validation of this prediction was unveiled by optical engineers at the University of Illinois at Urbana–Champaign—the world's first camera designed to mimic the way insects perceive the world. Compared to the eyes of most bugs, this camera is primitive, capable of taking only black-and-white photos with 180-pixel resolution. Ultimately, though, its creators intend to work up to the "full dragonfly-eye experience."
- University of Minnesota–Duluth: Evolution of the Insect Eye
- Smithsonian.com: This Camera Looks at the World through an Insect’s Eyes
- Springer Reference: Human and Animal Vision
- Humboldt Foundation: Interview: Through the Eyes of a Bee
- Anthony Campbell Book Review: Andrew Parker: "In the Blink of an Eye"
- In the Blink of an Eye: How Vision Kick-Started the Big Bang of Evolution; Andrew Parker
- John Foxx/Stockbyte/Getty Images