North America Speyeria butterflies and Asian outgroups Sbf1 restriction enzyme associated DNA sequence

The North American genus Speyeria is an especially challenging radiation of butterflies due to potential signs of incomplete lineage sorting, ongoing hybridization, and similar morphological characters between species. To achieve phylogenetic resolution of the genus, we conducted phylogenomic and population genomic analyses of all currently recognized North American Speyeria species, as well as several subspecies, using restriction site associated DNA sequencing (RADseq). Together, our analyses support 16 of the 17 putative species analyzed, validating previous taxonomic work. However, a few relationships within Speyeria were poorly supported depending on the evolutionary model applied. This lack of resolution among certain taxa corroborates Speyeria is experiencing an ongoing adaptive radiation, with incomplete lineage sorting and lack of postzygotic reproductive barriers contributing to hybridization and further ambiguity.