Hornets keep nests level with titanium, according to a report in Nature vol. 411, p654, 7 Jun 2001. Israeli and Dutch biologists have found crystals made of a mixture of titanium, iron, carbon and manganese hanging from the ceilings of cells in hornets’ nests. This rather exotic combination of metals is similar to a magnetic mineral named ilmenite and is used by the hornets as a type of plumb line or spirit level to help maintain the symmetry and balance of the cells as they build additions on to the nest. The crystals are stuck to the ceiling using glue secreted by the wasps and are suspended in just the right location to move when the nest moves without damaging the baby wasps inside the cells. No-one knows how the wasp obtains the crystals of titanium.
Editorial Comment: Nest building insects produce some remarkable structures that can be copied only by using intelligent human architects and engineers. It is absurd to think that wasps with brains smaller than a sesame seed invented geometrical nests and developed the metallurgy skills to obtain titanium crystals by chance. (ref. design, wasps, metallurgy)