Materials & methods
Collection of V. emeryi samples
Either individuals or colonies of V. emeryi were collected from 74 locations between 2010–2013, including 65 locations in South Korea, eight in Japan, and one in the United States (Table S1). Since this ant species usually lives in moist conditions, particularly in rotten wood, the collection sites were mountains or forests, and a large number of sampled colonies were found under the bark of rotten trees. For genetic analyses, 1–3 individuals per colony were sacrificed in 100% EtOH.