The evolution of ultraviolet patterns in European Colias butterflies (Lepidoptera, Pieridae): A phylogeny using mitochondrial DNA

Ultraviolet patterns in butterflies have been recognized and studied for many years and are thought to be involved in species recognition and sexual selection. Recent hypotheses state that sexually selected traits may be subject to relatively fast continual change over time. As a result, closely related species can differ markedly in sexual traits but hardly at all in nonsexual morphology. A molecular phylogeny of European Colias is reconstructed, not only to elucidate patterns of colonization and spread, but also to show whether those species with or without UV patterns constitute two monophyletic groups, or, as might be expected from the hypothesis, they are polyphyletic. The phylogeny indicates that the European species form three monophyletic clades corresponding broadly to their geographical distributions. The Scandinavian species appear to be the oldest in Europe and last shared a common ancestor with those from the USA. From Scandinavia they have radiated to the rest of Europe forming an eastern clade and a western clade. The presence of UV is polyphyletic within the whole group (and within each clade), consistent with the hypothesis that UV is a trait under intra- and/or interspecific selection.