Weevil's Hip Joint Fits Together Like a Screw and Nut
Posted on July 4, 2011
Researchers have discovered that the weevil's hip joint fits together like a screw and nut. In nature, hips and shoulders usually are based on ball-and-socket systems or hinges. The hip of Trigonopterus oblongus consists of joints based on a screw-and-nut system. This first biological screw thread is about half a millimeter in size. It was studied in detail using synchrotron radiation. The discovery is reported by the current issue of the Science magazine.
Thomas van de Kamp from Karlsruhe Institute of Technology says, "Such a construction for animal leg movement is quite unusual, as large areas of skeletal parts move on top of each other. Supply of the leg takes place via a very small opening in the center of the screw."
The researchers say the screw joint helps the weevil move their legs further down, which makes them better climbers. The researchers found the same screw joint in other weevil species.
Alexander Riedel from the Karlsruhe State Museum of Natural History says, "Meanwhile, we have also studied other weevil species and always found screw joints. Obviously, this joint exists in all weevils, of which more than 50,000 species exist worldwide."