Hydnophytum formicarum is one of the most typical ant-plants distributed in Southeast Asia. The dolichoderine ant, Philidris cf. cordatus nests in the domatia of H. formicarum. We discovered nest capture of the two widespread ant species Tapinoma melanocephalum and Tetramorium nipponense in Phnom Bokor National Park, Cambodia. The two species used nests that dropped on the ground near the road that goes to the top of the mountain. The mutualistic relationship between ants and ant-plants is usually stable, but environmental change due to deforestation can easily provide a breeding ground for such widespread species. The intraspecific sequence divergence between Japanese and Cambodian T. nipponense specimens was 8.6% (K2P distance) for the mtDNA COI 3′ region. The deep genetic gap suggests that T. nipponense is native to Asia.