Spontaneous;eggs yellowish white, gradually becoming red-tinged, compound eye white; 3-hydroxykynurenine cannot be converted into pigment due to the enzyme deficiency: w-2r(赤眼第2白卵, red eyed w-2, MNU-induced) like w-2 but compound eyes deep pink.
Symbol;w-2
Positional cloning of silkworm white egg 2 (w-2) locus shows functional conservation and diversification of ABC transporters for pigmentation in insects.