Bug's-Eye View

Scientist Jenny Read shows action-packed 3-D movies in her lab at Newcastle University in England. But they aren’t Hollywood blockbusters you may have seen. These films were made for insects! 

Read uses the movies to test the vision of praying mantises. She recently did an experiment to find out if the insects can see in 3-D.

Scientist Jenny Read shows action-packed 3-D movies in her lab. She’s a scientist at Newcastle University in England. Read’s movies aren’t Hollywood blockbusters you may have seen. These films were made for insects! 

Read uses the movies to test the vision of praying mantises. She recently did an experiment to find out if the insects can see in 3-D.

Like humans, many animals with front-facing eyes have binocular (bye-NOK-yoo-luhr) vision. Each eye sees a different, but overlapping, view. The brain combines the two images into one 3-D picture. This creates a sense of depth, or ability to tell how far away things are.

Animals without binocular vision see completely different images in each eye. They don’t see the world in 3-D. 

Read and other scientists suspected that mantises have binocular vision. But Read wanted to know for sure. To find out, she fitted the insects with bug-sized 3-D glasses. “They’re similar to the glasses you’d wear at a 3-D movie,” she says. 

During a 3-D movie, two images are projected onto a screen at once. Each lens of the glasses blocks a certain type of light. That means a viewer’s left eye sees one image while the right eye sees the other. Together, the two views make objects appear to leap off the screen. 

If mantises had binocular vision, they’d react to 3-D movies as if objects were right in front of them. If not, they wouldn’t fall for the 3-D effect.

Humans have binocular (bye-NOK-yoo-luhr) vision. Many animals with front-facing eyes do too. Each eye sees a different but overlapping view. The brain combines the two images. It forms one 3-D picture. This creates a sense of depth. That’s the ability to tell how far away things are.

Some animals don’t have binocular vision. They see completely different images in each eye. They don’t see in 3-D. 

Read thought mantises might have binocular vision. She wanted to know for sure. So she fitted the insects with bug-sized 3-D glasses. “They’re similar to the glasses you’d wear at a 3-D movie,” she says. 

Two images are projected onto a screen at once during a 3-D movie. Each lens of the glasses blocks a certain type of light. That means a viewer’s left eye sees one image. The right eye sees another. Together, the two views make objects appear to leap off the screen. 

If mantises had binocular vision, they’d see 3-D movies the way people do. They’d react as if the images were right in front of them. Otherwise, they wouldn’t fall for the effect.

After placing glasses on the mantises, Read showed them movies of a black dot. The dot darted around like a bug a mantis would eat. 

When the fake prey 
was shown in 2-D, the mantises ignored it. They knew the dot on the screen was too far off to catch. But when the film was in 3-D, the mantises swiped at the dot. That’s because it seemed to hover within their reach. The insects really could see in 3-D!

Not only did Read prove that mantises have binocular vision, but she also thinks she knows why they need it. Mantises are stealthy hunters. They sit perfectly still until a bug passes by. Then they attack. “They only have one chance to strike,” says Read. “So judging depth is really important to them.”

Read placed the glasses on the mantises. Then she showed them movies of a black dot. The dot darted around like a bug a mantis would eat. 

The mantises ignored the fake prey when it was shown in 2-D. They knew the dot on the screen was too far off to catch. But the mantises swiped at the dot when the film was in 3-D. That’s because it seemed to hover within their reach. The insects really could see in 3-D!

Read proved that mantises have binocular vision. She also thinks she knows why they need it. Mantises are stealthy hunters. They sit perfectly still until a bug passes by. Then they attack. “They only have one chance to strike,” says Read. “So judging depth is really important to them.”