Structure of a character and the evolution of butterfly eyespot patterns

All butterfly eyespots appear to be formed by a similar developmental mechanism. Thus the great diversity of patterns observed across different species of butterfly has evolved through changes in the genetic modulation of this mechanism. Our descriptions of both the development of eyespots and the genetic variation for eyespot traits in an African butterfly, Bicyclus anynana, are used here to discuss the most appropriate ways of applying the character concept to the evolution of butterfly eyespot patterns. J. Exp. Zool. (Mol. Dev. Evol.) 291:93-104, 2001.