Structure and Development of Iridescent Lepidopteran Scales: the Papilionidae as a Showcase Family

Abstract

Many types of structurally colored scales have been reported among the Lepidoptera. These include scales displaying diffraction colors, Tyndall blue, and at least three kinds with thin-film interference colors. Despite this variety within the group as a whole, however, most individual families appear to be fairly conservative, showing only one or two color types within their ranks. The Papilionidae are apparently more versatile than other families in this respect, for within this one group are found all the structurally colored scale types reported so far in all other families, as well as at least two additional varieties that are not. This paper reviews the architecture of structurally colored scales in 23 species from five genera of papilionid butterflies, describes the two previously unreported scale types, and discusses the developmental and phylogenetic implications of such a great variety of complex and specialized scale types within a single group.