The distribution of radiolabeled pigment precursors in the wing patterns of nymphalid butterflies

Abstract

Study of radiolabeled tyrosine (precursor of melanin), and tryptophan (precursor for 3-hydroxykynurenine and ommochromes, orange to brown) in Precis coenia, Inachis io, Aglais urticae, Araschnia levana, Heliconius charitonia, and Agraulis vanillae. Tyrosine always labeled black and dark brown pattern elements, whereas tryptophan labeled red, orange, brown, and tan portions. Mostly, two pigment pathways appear to exclude each other in single scales, except sometimes in A. levana.