Lepidoptera feathers and hair, bran, semolina and flour (possibly preferring wheat flour), biscuits, casein, and insect specimens in museums. Even though most butterflies and moths affect the economy negatively, some species are a valuable economic resource. The most prominent example is that of the domesticated silkworm moth ("Bombyx mori"), the larvae of which make their cocoons out of silk, which can be spun into cloth. Silk is and has been an important economic resource throughout history. The species "Bombyx mori" has been domesticated to the point where it is completely dependent on mankind for survival. A number of wild moths such
Bombyx mandarina true or mulberry silkmoths. The origin of the domesticated silkmoth is enigmatic. It has been suggested that it is the survivor of an extinct species which diverged from the ancestors of "Bombyx mandarina" millions of years ago. However, this is based on an untenable molecular clock hypothesis that assumes that wild and domestic silkmoths evolved equally fast after their lineages diverged. Rather, the effects of artificial selection have accelerated evolution in the domestic form to a point where it is hard to trace the origin of the numerous breeds of domestic silkworms even with the most modern molecular phylogeny methods.