Argentine ant (Linepithema humile) is one of the most widespread invasive ant species in the world. The species is a major threat to biodiversity because it can readily out-compete and displace native invertebrates, even to the point of local extinction. The worker ants can also interfere with nesting seabirds resulting in nest failure. The species can attain extremely high abundance levels because they form super-colonies containing hundreds of queens.
Argentine ants tend sap-sucking insects, like scale and aphids, making them a serious pest of crops. They are also a significant household pest infiltrating properties in large numbers in search of food and establishing nests within internal structures.
Argentine ants were first found on Norfolk Island in 2005. It remains unclear exactly how and when the ant arrived on the island, but it had undoubtedly been present for many years prior. The species is now known to occur in 14 discrete populations throughout approximately 400 ha of the Island’s 3529 ha.
To date, Argentine ant has proven very difficult to eradicate from anywhere in the world. The science challenge is to overcome the difficulties preventing eradication, especially in the many infested locations on the island with difficult terrain.
Since 2014, CSIRO has been working with Norfolk Island Regional Council on the Argentine Ant Eradication Project. The project aims to develop a management strategy for successful eradication. CSIRO has developed a treatment program which involves advanced hydrogel ant bait and the first use of a drone to conduct aerial treatments.
Australia’s largest non-military drone, The Fazer, is a prototype autonomous drone owned and operated by Yamaha Sky Division. The drone is being used to disperse bait over infested areas with very steep terrain covered in dense bush.
Post-treatment assessments have involved the use of a professionally trained detector dog. The world's first Argentine ant detector dog was trained in New Zealand in 2015, and a second is now in use on Norfolk Island.
To date, Argentine ant has been declared eradicated from three small zones and near eradication in a further four zones covering a combined area of approximately 50ha. Importantly, work to date has demonstrated that multiple treatment methods can achieve eradication.