Asian Needle Ant

Brachyponera chinensis — the Asian needle ant — is one of the most consequential rapidly-spreading invasive ants in the eastern US in the 21st century. Native to East Asia (China, Japan, Korea), the species was first detected in Decatur, Georgia in 1932 in a shipment of cotton from Asia. The species remained an obscure local curiosity for decades but exploded in abundance and range starting in the 2000s, and has since spread from northern Florida through the Carolinas, Virginia, the mid-Atlantic, and into New York. The species is small (5 mm), dark brown to black, and lives in colonies of 100-3,000 workers in soil, leaf litter, rotting logs, and (notably) inside human dwellings. Two features make Asian needle ant medically and ecologically significant. First, the sting: rated 1.7 on the Schmidt Pain Index (comparable to a yellowjacket sting and significantly more painful than most ant stings), and unlike most ant stings, asian needle ant venom contains compounds that have caused documented severe allergic reactions including anaphylaxis. The University of Georgia documented multiple ER visits per summer in heavily-infested counties. Second, the ecological displacement: native eastern US ants — especially Aphaenogaster species — provide the critical ecosystem service of myrmecochory (seed dispersal of native woodland herbs including bloodroot, trilliums, and trout lilies). Asian needle ant aggressively displaces Aphaenogaster from forest litter habitat but does NOT itself perform myrmecochory; the result is a documented decline in spring ephemeral wildflower populations across the species' invaded range. The species is one of the most-monitored invasive ants by USDA APHIS in the 2020s.