Ommochrome Pigmentation of the linea and rosa Seasonal Forms of Precis coenia (Lepidoptera: Nymphalidae)

Precis coenia exhibits a seasonal color polyphenism. Animals reared under long-day conditions develop a pale tan pigmentation on their ventral hind wing (the linea form), whereas animals reared under short-day conditions develop a dark reddish-brown pigmentation (the rosa form). This developmental switch is mediated by a shift in the timing of ecdysteroid secretion at the outset of adult development. In addition, a single recessive gene mimics the effect of shortday conditions and, when homozygous, produces a constitutive rosa phenotype. This article analyzes the pigment composition of the ventral hind wing pattern of the linea and rosa forms. It presents a new thin layer chromatography system that separates ommochromes with high resolution. The linea pigmentation was found to be due to xanthommatin, while the rosa pigmentation is due to a mixture dihydro-xanthommatin and ommatin-D. Induction of the rosa form thus requires the synthesis of a new pigment (ommatin-D is a sulfate of dihydro-xanthommatin) and the stabilization of the reduced form of xanthommatin. Arch. Insect Biochem. Physiol. 36:215–222, 1997. © 1997 Wiley-Liss, Inc.