Mapping a morphometric analysis of butterfly and moth wing scale shape to a family level phylogeny

The dense covering of scales on the wings of butterflies and moths not only gives their order (Lepidoptera) its scientific name, but also forms the basis for the attractive color patterns present in many species. Wing scales (average length ~ 200 µm) are homologous to insect bristles (macrochaetes), and their colors create the patterns that characterize lepidopteran wings. The outlines, topologies, and surface sculpture of wing scales vary widely, and this architectural complexity arises from variations in the developmental program of the individual scale cells of the wing epithelium. We have described adult macrochaete morphology in over 60 families throughout the lepidopteran order and performed a morphometric analysis to distinguish unique characters at a familial level. We then created a character map (using mesquite) in order to connect lepidopteran phylogeny with the shape of wing scales. Our results have allowed us to not only to describe what the differences in wing scale shapes throughout the Lepidoptera are but also to understand how and why these differences arose in evolutionary time.