Praying Mantises Use 3D Vision To Hunt, Study Confirms

After taking the seemingly outlandish action of fitting miniature glasses to insects, researchers from Newcastle University say they have confirmed that praying mantises have 3D vision. This find could help scientists understand how vision evolved in humans, and ultimately improve visual perception in robots. 

"Despite their minute brains, mantises are sophisticated visual hunters which can capture prey with terrifying efficiency. We can learn a lot by studying how they perceive the world," Jenny Read, study leader and professor of vision science, said in a news release. "Better understanding of their simpler processing systems helps us understand how 3D vision evolved, and could lead to possible new algorithms for 3D depth perception in computers."

Here's more about those glasses. The researchers fitted mantises with custom-made 3D glasses and tested their visual response in a specially-designed insect cinema. Compared to the "old-school" red and blue lenses of human 3D glasses, the 3D glasses used on the mantises had one blue and one green lens because they are unable to see red light. The tiny lenses were attached to the insects using beeswax.

Stereopsis, or 3D perception, was first observed in mantises in the 1980s by Samuel Rossel of the University of Zurich. However, his work featured only prisms and occluders (vision blockers), which limited the amount of images that could be shown.

Using miniature glasses, on the other hand, allowed researchers to project any number of images. This includes short videos of simulated bugs moving around a computer screen. While mantises did not try to catch the bugs that were projected in 2D, they did attack the ones shown in 3D, proving the insects effectively use 3D vision to hunt. (Scroll to read more...)

"We definitively demonstrated 3D vision or stereopsis in mantises and also showed that this technique can be effectively used to deliver virtual 3D stimuli to insects," Dr. Vivek Nityananda, one of the study researchers and a sensory biologist at Newcastle, added in the university's release.

Next researchers plan to use their findings to further explore depth perception in insects, which will help them better understand how human vision evolved and develop new ways of adding 3D technology to computers and robots.

Their study was recently published in the journal Scientific Reports. 

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