When tarantulas grow blue hair
Origin of color is unclear, but evolved multiple times
By Susan Milius
Roses are red. These tarantulas are blue. They can’t see their color, so what does blue do?
Among the various tarantula hues, “the blue color is mysteriously widespread, ” says Bor-Kai Hsiung of the University of Akron in Ohio. At least one species of tarantula flashes some blue in 40 of the 53 genera he checked. Mapping them onto a tarantula family tree, Hsiung estimates that the color evolved independently at least eight times. At first, he wondered if color among the colorblind spiders was a by-product of some more useful trait. But evidence led elsewhere.