Argentine ant
Formicidae - Linepithema humile
BioSecurity

What does it look like?

Argentine ant: worker ants are only 2–3 mm long and are a uniform honey-brown colour.  Foraging ants move steadily (not slowly) in defined continuous trails that can often be seen going up trees or shrubs, especially if these are flowering.  The ants can't sting but some people react to their bite.  They have a slight greasy odour when crushed, as opposed to the strong formic acid smell of some ant species.

Argentine ants are frequently associated with areas of human settlement but they are not entirely restricted to modified habitats.  In New Zealand, Argentine ants have invaded native habitats including scrub, mangroves, coastal forest and the edges of native forest, but forest habitat appears unlikely to be utilised.

Why is it a problem?

Argentine Ants are widespread in the Northland Region.  They favour sandy coastal soils and volcanic soils but have also been found in other areas, particularly in association with human activity.  They are being moved around the region by people (e.g. in potted plants, beehives, soil etc.). They are not currently known to be on any of Northland's offshore islands.

Nests of Argentine ants have multiple queens and are capable of multiplying into huge numbers in a very short time.

Control Methods

If you suspect you have Argentine ants you can get them identified by delivering a sample to a Northland Regional Council office. Ant samples should be put into a screw-top container and frozen.

For prevention:
Ensure soil potted plants, outdoor equipment or other mediums which could contain ants are ant-free before moving these to other areas.

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