The geography of speciation in butterflies (Lepidoptera, Papilionoidea): an empirical test of theoretical models

Despite the fundamental role of speciation in formation of biodiversity, the genetic and ecological mechanisms related to this process, as well as the geography of speciation are still poorly known. In our research we have used methods of molecular phylogenetics and phylogeography to reconstruct the stages of speciation in two model groups of butterflies. Phylogeographic analysis showed that speciation in Agrodiaetus blues started in allopatry. An additional age-range correlation test also revealed a pattern consistent with allopatric speciation. However, the formation of new wing colors, the characters most important for maintenance of pre-zygotic reproductive isolation, was shown to occur after transition from allopatry to sympatry. Analysis of karyotypes, mitochondrial and nuclear molecular markers in the Wood White butterfly Leptidea sinapis L. showed that clinal speciation may have occurred in this case; this process is theoretically possible but difficult to document.