MAF on the trail of the Red Imported Fire Ant

18 June 2001

The Ministry of Agriculture and Forestry is asking communities in the upper North Island region to remain on the alert for signs of the Red Imported Fire Ant (RIFA).

RIFA, native to South America, are tiny, but aggressive, reddish-brown ants with a fierce sting. Outside of South America, RIFA have become significant environmental, economic and human health pests.

A RIFA nest was discovered and subsequently destroyed at Auckland International Airport in March 2001. No further RIFA have been found at the nest site or in searches of the surrounding areas. However, MAF has concerns that the ant might have flown from the nest or been carried to a new location by wind or human means, prior to the ant nest's destruction.

MAF's response to date has included intensive local surveillance, a mail drop to all 95,000 properties within the potential flight path of the nest and a targeted awareness campaign to alert people most likely to come into contact with and/or recognise RIFA or signs of RIFA stings.

Nationally the campaign has targeted groups such as quarantine services, airport and port authorities, public health units, doctors, veterinarians, Department of Conservation, Forest and Bird offices and SPCA branches. Field surveillance will continue for at least the next two years.

MAF is confident that any other mature nests in the area would have been detected through the current investigations. However, a RIFA colony takes several months to develop before worker ants will start foraging above ground level. Foraging habits of RIFA are very weather dependent and they will only usually be seen above ground on days where temperatures reach 20C or more.

Given the unseasonably warm autumn weather recently, there may still be a window of opportunity to detect any maturing colonies prior to the onset of winter. Intensive surveillance will be carried out by MAF in spring and summer when the weather warms up.

Although New Zealand has several species of red ant that look similar to RIFA, RIFA have a number of distinguishing features:

  • The ants build mounds of fine granular soil. These mounds vary in size and are often built in sunny, open areas, sometimes against a wall, post or scrub. RIFA are also known to build colonies in electric boxes and walls of homes and other dwellings.
  • The ants will swarm if their nest is disturbed and will crawl onto and sting anything nearby. A RIFA sting is painful, similar to that of a bee or wasp. Symptoms include intense burning and itching. A blister forms at the site of the sting, followed by the formation of a white pustule within a few days. In comparison New Zealand ant species will not swarm or sting (although some may bite). NZ ants will not build mounds.
  • If a person is unfortunate enough to be stung they should not panic. The sting, although uncomfortable, is not dangerous to most people. However the pustules may become infected if scratched. On very rare occasions when people may have a more serious or allergic reaction, it is important that they seek medical advice immediately.

As temperatures fall, evidence of RIFA will become less obvious, but if RIFA are still at large activity will renew in spring. In the meantime MAF will continue to identify and to work with affected communities to alert them to the possibility of RIFA presence and to ask for reports of suspect ants.

To report suspected findings of RIFA call the MAF Exotic Pest Hotline on 0800 80 9966.

Contact MPI

for general enquiries phone

0800 00 83 33