Phylogenetic Relationships Based on DNA Barcoding Among 16 Species of the Ant Genus Formica (Hymenoptera: Formicidae) from China

In this study, we sequenced fragments of cytochrome oxidase subunit 1 (CO1), internal transcribed spacer 1 (ITS1), and internal transcribed spacer 2 (ITS2) genes from 150 specimens belonging to 16 species of the ant genus Formica from China. Odontoponera transversa from Ponerinae and Polyergus samurai from Formicinae were added as distant relative and close relative outgroups, respectively. Neighbor-joining, maximum parsimony, and Bayesian interference methods were used to analyze their phylogenetic relationships based on CO1 gene sequence as well as combined sequence data of CO1 + ITS1, CO1 + ITS2, and CO1 + ITS1 + ITS2. The results showed that nine Formica species (i.e., Formica sinensis, Formica manchu, Formica uralensis, Formica sanguinea, Formica gagatoides, Formica candida, Formica fusca, Formica glauca, and Formica sp.) formed monophyletic clades, which in agreement with the results based on morphological taxonomy. By comparing the results of DNA barcoding and morphological taxonomy, we propose that Formica aquilonia maybe a junior synonym of F. polyctena and that cryptic species could likely existed in Formica sinae. Further studies on morphology, biology, and geography are needed to confirm this notion.