Praying Mantises Use 3D Vision

A new research done by the Newcastle University proved that the praying mantises use 3D vision. The mantises are also known as Mantodea are a species of insects that contain around 2,400 other species. Mantises live in the temperate and tropical areas of the world. They have triangular heads and very big eyes. Their bodies are long and adapted for catching prey. Because they were usually found with the arms folded, they were named praying mantises.

The first time that the 3D vision of the praying mantises was tested was in 1980. Back then, researchers used occluders and prisms in order to prove their theory. Those devices could only show a few images, but it proved to be successful nonetheless.  The method they used was putting prisms that had different powers in front of the mantis’s eyes. This caused many errors, and it was not a direct test.The praying mantis is actually the only invertebrate to have a 3D perception.

The team of researchers from the Newcastle University wanted to take that 1980 study a step further, so they thought of using 3D glasses fit for the mantis. They also created a mini cinema and wanted to see if the insects would move accordingly. The mantises did, but only for one type of images.

Firstly, the team used tiny 3D modern glasses, but the experiment was unsuccessful. For the modern glasses, each lens either blocks, either lets through a certain polarized light. This way, two images can be seen at the same time. Although they work for humans, they didn’t work for the mantises.

When they tried the second time, they used the traditional 3D glasses and the theory that the mantises have a 3D vision was proven once more. Because mantises can’t see the red light well, the blue and red lenses were changed with green and blue ones. After that, mantises were shown an image of a dark prey. When the image was 2D, the mantises didn’t strike, but when it changed back to 3D, the mantises struck, as the prey appeared to come out of the screen.

The researchers believe that one of the reasons why the more modern glasses didn’t work because the first time, the insects were positioned too close to the screen, and they couldn’t separate the images correctly.

The conclusion of the study is that not only do the praying mantises use 3D vision, but they can also be stimulated by 3D images. The team of researchers believes that the findings could help create new algorithms for future 3D perception.

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