The colouring of many species has unknown function. This is usually because their life habits have not been studied sufficiently, and because no field tests have been done. One example is the extraordinary moth "Utetheisa pulchella", the Crimson Speckled Moth. Its association with the plant "Dittrichia viscosa", which has a somewhat unpleasant smell, suggest the moth has warning colouration, but the matter is not settled. The related species "Utetheisa ornatrix", which feeds on other plants, is known to exude (squeeze out) alkaloids to put predators off.