Scientists have discovered a unique kind of 3D vision in praying mantis, which could eventually help researchers develop more effective eyes for robots. Many animals, like humans, are capable of perceiving three-dimensional objects and structures. However, the only known insect to have 3D vision or stereo vision is the praying mantis.

However, a new study uncovered that the praying mantis' 3D vision is unique – which means it works differently than stereo vision works for humans. The new study involved scientists at the Newcastle University creating a customised pair of 3D glasses that were temporarily glued on to the praying mantis with beeswax.

The researchers showed the bespectacled praying mantis movies, using a simplified version of the same technology that allows us humans to watch movies in 3D, in order to determine their depth perception.

The mantis was shown two types of movies – one which showed video clips of moving prey, while the other featured static patterns of dots and a moving spiral of dots. The researchers discovered that not only could the praying mantis identify the prey in the movies but the creature also tried to capture the prey.

The researchers uncovered that while humans are fairly good at seeing in 3D in still images, mantises don't really need 3D vision to work in still images, since they attack only moving prey. In other words, mantises' depth perception only focuses on objects or things that are changing. The scientists discovered that the praying mantises were able to spot changes in the movies that human eyes were incapable of identifying.

praying mantis 3D vision
Scientists discovered that the praying mantises were able to spot changes in the movies that human eyes were incapable of identifying University of Newcastle

"This is a completely new form of 3D vision as it is based on change over time instead of static images," Dr Vivek Nityananda, behavioural ecologist at Newcastle University, said in a statement. "In mantises it is probably designed to answer the question 'is there prey at the right distance for me to catch?'"

"Many robots use stereo vision to help them navigate, but this is usually based on complex human stereo. Since insect brains are so tiny, their form of stereo vision can't require much computer processing," said Dr Ghaith Tarawneh at Newcastle University's school of engineering, who was also involved in the research. "This means it could find useful applications in low-power autonomous robots."

The findings of the new research have been published in the journal Current Biology.