Taxonomic status and molecular phylogeography of two sibling species of Polytremis (Lepidoptera: Hesperiidae)

The skipper Polytremis theca species complex is widely distributed in the south of the Qinling Mountains in China. A recent study of the Polytremis genus suggested that this species might encompass two differentiated lineages. We tested this hypothesis, by carrying out a phylogenetic study of this agricultural pest based on nationwide sampling and the evaluation of mitochondrial and nuclear DNA markers. We show that this species is actually an amalgamation of two sibling taxa (P. t. theca and P. t. fukia), which displayed levels of genetic divergence as great as those generally found between sister species in the Polytremis genus, suggesting that they actually correspond to two distinct species. The Divergence time estimates suggest that an active period of speciation within Polytremis occurred within the Pleistocene eras. Based on its distinct phylogenetic placement and geographical isolation, we suggest that the subspecies should be elevated to full species status under the phylogenetic species concept, which has significant management implications.