Exotic ant found in Dunedin

2 December 2003

A tiny ant easily mistaken for a midge may have become established in Dunedin.

The Ministry of Agriculture and Forestry (MAF) is asking Dunedin residents to be on the lookout for Hypoponera punctatissima or Roger's ant. This is a secretive ant and is most likely to be recognised when winged females swarm in large numbers on warm nights.

Amelia Pascoe, MAF's Programme Coordinator Exotic Animal Response, said Roger's ant is most likely to be found in places of human habitation as it is attracted to warm, moist areas and often form small colonies in buildings with damp areas such as leaking pipes and drains. It is unlikely to be found in domestic homes and is most likely to occur in factories, institutions, hotels, food premises, laundries, and other buildings where there is a significant continuous source of heat.

"The ant is very small and easily dispersed by wind. Only the females fly and will swarm in large numbers; generally they grow to around 3.5mm. The males are smaller at 2 to 3 mm and stay in the nest; workers are also about 2-3 mm and are hard to detect as they do not form trails," she said.

MAF at this stage does not know how long the ant has been in Dunedin or how widely it is distributed.

Roger's ant was first noticed during renovations of a Dunedin building last summer. It is believed that after a nest was disturbed winged female ants were produced in large numbers and were distributed by wind and hot air from the building's ventilation system. Staff initially thought the insects were flying midges but confirmation of Roger's ant was made when the owner submitted samples for identification in July 2003.

"These ants are a nuisance and are capable of stinging, although, generally they do not pose a significant human health risk, especially in cool temperate areas where the ants is less active. Those stung suffer a reddened, itchy lump that may last for several days. This can be relieved by applying a cold compress (e.g. ice in a cloth, plastic bag or plastic wrap) on the site for 15-20 minutes.

In very rare cases some individuals who are stung may experience an allergic reaction and should seek medical attention immediately," she said.

Overseas experience indicates that Roger's ant can also be a nuisance in the food and pharmaceutical industries because of their tendency to infest heated industrial buildings. Effective pest control, hygiene and building maintenance will assist in managing this pest.

Roger's ant is present on the Kermadec Islands which lie 1000km Northeast of New Zealand. This is the first record of Roger's ant on the New Zealand mainland.

If you find what you believe is a Roger's ant please call the MAF Exotic Disease and Pest Emergency Hotline on 0800 809 966.

MAF has been working alongside the New Zealand Food Safety Authority, the Ministry of Heath, the Department of Conservation, and the Otago Regional Council during this investigation.

For further information:
Philippa White Senior Communications Adviser 04 498 9948 or 027 223 1875



Last Updated: 05 October 2010

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