Van De Kamp T., Vagovic P., Baumbach T., Riedel A.
in Science, 333 (2011). DOI:10.1126/science.1204245
The coxa-trochanteral joints on the legs of the weevil Trigonopterus oblongus (Pascoe) work as a biological screw-and-nut system. The apical portions of the coxae closely resemble nuts with well-defined inner threads covering 345°. The corresponding trochanters have perfectly compatible external spiral threads of 410°.