By Mark Brown, Wired UK

Think nuts and bolts are exclusive to mechanics and engineers? Think again. The Trigonopterus oblongus weevil has been using the mechanism in its hips for 100 million years.

Using samples from the Karlsruhe State Museum of Natural History and the instruments at the Institute for Synchrotron Radiation at the Karlsruhe Institute of Technology (ANKA), biologists have made computed tomography (CT) scans of the Papua New Guinea bug.

They found that the weevil didn’t have the classic ball-and-joint or hinged appendages seen in other animals and insects. The beetle instead has a distinctly spiral-shaped tip to the leg, and a threaded coxa, which acts like a hip.

The two body parts screw in together, and then allow for around 130 degrees of rotation on the back legs, and 90 degrees on the front. It doesn’t make them better walkers — weevils are rather clumsy beetles — but it can help with climbing.

By being able to move their legs further down, the Trigonopterus can get a better foothold on the leaves and twigs of the Papua New Guinea jungle, as it climbs to higher areas and better food. The screw system is also less likely to become dislocated.

Since the discovery, researchers at the museum and ANKA have studied another 15 weevils and discovered the same screwy joints on all of the tiny beetles. “Obviously, this joint exists in all weevils, of which more than 50,000 species exist worldwide,” explains Alexander Riedel from the Karlsruhe State Museum in a press release.

Source: Wired UK

Image: Science

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