Ectopic eyespots and expression of eyespot patterning genes. Eyespots of WT (top) and Spr individuals (bottom) differ in colour scheme in adults, and in gene expression patterns in developing pupal wings. (a) Anterior distal part of dorsal adult forewings showing native and damage-induced eyespots formed around wound sites (stars). The colour composition of the ectopic eyespots resembles that of the native eyespots and reveals differences in the response properties of wing epidermal tissue between WT and Spr butterflies (solid and dashed rings outline the Spr native and the ectopic eyespots, respectively). These differences are reflected in the expression patterns of en (b), Dll (c) and sal (d) in 16- to 18-hr old pupal wings. Spr mutants were chosen for these experiments because they exhibit the most severe, and thus most noticeable, effects on eyespot phenotype, including damage-induced ectopic eyespots.