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
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
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.