Scientists make tiny 3D glasses for insects to understand how they see the world

Putting 3D glasses on praying mantises has given researchers insights into the unusual stereo vision of the insects.

Some of the same group of scientists had created a spectacle in 2016 by outfitting praying mantises with miniature 3D specs. They went a step further this time, taking a closer look at how mantises perceive objects in three dimensions.

Whereas earlier research had shown that mantises could see in 3D the only known insects to do so - the scientists' new study describes experiments comparing mantises' vision to human vision.

According to their findings, mantises arrive at their 3D perception by processing visual information differently than people do, an unusual technique that allows mantises to see some objects in 3D even when humans cannot.

Stereo vision, also known as stereopsis, allows some animals including humans and mantises, to perceive their distance from objects.

Slight differences in the images of what they see are relayed to the brain and processed into a single image and the subtle variations in the two original views help the brain pinpoint the location of the object in three dimensions, the scientists wrote in the study.  

The mantises that were fitted with 3D glasses using beeswax were shown 3D footage. The researchers studied the response of the insects to 3D video of prey insects which they tried to catch.

According to the team at Newcastle University's Institute of Neuroscience, their findings on the insects' unique form of ''stereo'' sight, in which two views are merged to create a single image, could lead to important advances in robotics.

''Mantises only attack moving prey, so their 3D doesn't need to work in still images,'' said behavioural ecologist Vivek Nityananda, one of the authors of the study. ''We found mantises don't bother about the details of the picture, but just look for places where the picture is changing.''