Glasses reveal how the mantis can see in 3D even when humans can't

9 February 2018, 09:23

Researchers using miniature 3D glasses have discovered how the praying mantis' unique vision allows them to spot objects in three dimensions even when humans cannot.

A study by scientists at Newcastle University compared the vision of the mantis - the only known insect which can see in 3D - to that of humans, and found the creatures performed better at detecting the distance to a moving object.

The glasses were attached to the eyes of the insects by beeswax, with the mantises suspended upside down in front of a computer screen showing 3D footage of prey.

:: Praying mantises given 3D specs by scientists

The insects would try to catch the prey, so the researchers subjected them to vision tests typically given to people to try and determine how the mantises reach their 3D perception.

With humans, each eye sees a slightly different view of the world. The brain merges those two images to create one, which helps us work out the distance to objects.

People and animals including monkeys, cats, horses and owls compare the brightness of the two images to visualise 3D space. This process is known as stereo vision, or stereopsis.

But mantises focus on where the brightness is actively changing between the two images, allowing them to tell the distance to their target even when it is camouflaged against a similar background, the study found.

Vivek Nityananda, lead author of the study, said: "This is a completely new form of 3D vision, as it is based on change over time instead of static images.

"In mantises, it is probably designed to answer the question 'Is there prey at the right distance for me to catch?'"

Professor Jenny Read, of the university's institute of neuroscience, said she believes the research could have a wider impact in automation.

She said: "Reducing the amount of computer power necessary means smaller, lightweight robots could use mantis stereo algorithms to detect depth."

Mantis cannot see in 3D if the image is static, but their visual technique means they can detect distance to a moving object better than humans under certain circumstances, including when there is a difference in brightness between images from both eyes, according to the study.

The findings were published online on Friday in the journal Current Biology.