 The blues produced by nanostructures in "Maratus" do not fade over time, unlike the normal pigmenting method.Other blue animals, like beetles, are rare but also use nanostructures.Nathan Morehouse of the University of Pittsburgh found "Maratus volans" have four different photoreceptors (tetrachromats) allowing them to see red, blue, green, and ultraviolet and also resolve the intricacies of the male’s display designs.