Establishment and Management of the Little Fire Ant, Wasmannia auropunctata (Hymenoptera: Formicidae) in Taiwan

抄録

The little fire ant, Wasmannia auropunctata, is an invasive tramp ant that causes damage on a global scale. Recently, this notorious ant species was first reported in Taiwan in 2021. This is considered the first confirmed case in the East Asian region. Colonies of W. auropunctata were found at two locations, i.e., Wuri and Heping districts in central Taiwan, which are separated by approximately 30 km. Both genetic and behavioral analyses revealed that the two populations were most likely introduced from a common source population, and form a unicolonial social structure. Furthermore, a microsatellite analysis showed that W. auropunctata populations in Taiwan also employ clonal reproduction. Because of its highly aggressive nature, we highlight the potential threats this invasive ant species poses to arthropod communities, agricultural systems and human health in this region, based on several field observations. A food lure method using potato chips was adopted to detect the presence of W. auropunctata. Since September 2021, the monitoring and chemical control of W. auropunctata populations have been addressed through a university-government partership. The eradication program included both ground and arboreal treatments. Ground treatments involved mixing granular baits containing pyriproxyfen (0.50w/w%) with granular baits containing hydramethylnon (0.73w/w%) at a ratio of 4:1, and then broadcasting the mixture onto the ground at an application rate of 2.5 kg/ha. Arboreal treatments involved spraying paste baits containing borax (2w/w%) at an application rate of 10 L/ha over tree trunks and vegetation.