NZers urged to stop aggro ant's spread

3:29 pm on 4 January 2017

New Zealanders are being asked to help exterminate an introduced ant that is a serious threat to native species.

Argentine ants

Argentine ants Photo: AFP / Hemis

Department of Conservation technical advisor Chris Green said Argentine ants were one of the world's most problematic ant species.

They were about 2-3mm long, honey-brown rather than black, and typically travelled in big trails "a bit like a motorway, five or six lanes wide, and they are very rapid-moving," Dr Green said.

They hunted in very large numbers and recruited very quickly when a food source was found, overwhelming it with their aggression and appetite.

"Basically they can kill just about any other insect we've got, native lizards as well, and they'll also kill chicks as they're hatching from the eggs in the nest. So they're a threat to our native wildlife."

Argentine ants arrived in New Zealand in 1990, and are mostly found in the northern half of the North Island as well as Nelson/Marlborough and Christchurch. They like coastal areas and have gravitated towards areas with high sunlight and warmth on the ground.

Over summer, the department has been trying to stop people from spreading them to areas where they are not already established.

"We want people to have a bit of vigilance, check their gear before loading the car and taking off with a trailer to make sure they don't have unwanted visitors like that with them," Dr Green said.

"The high-risk items would be potted plants, any garden materials. Materials that are stored on the ground like tents, the kayak that hasn't been moved all year, or dinghies. These could have ant nests in them, and we want to make sure that those nests don't travel with those commodities when people go on holiday."

Any ants found in a tent or kayak should be regarded as suspicious and should be killed, he said.

"Once you start moving an item, if there's an ants' nest in it, the ants will come boiling out of it, so they usually make themselves very apparent.

"If you spot a nest, if you spot a lot of ant activity on anything that you are moving, spray it with fly spray immediately and that will certainly do the job," he said.

Dr Green said, unlike other species of ants, Argentine ants were spread by humans.

"Unlike other ants, Argentine ants don't have a winged stage, so they don't have mated females that fly away to start a new nest. These ants can only spread basically by walking from a mother nest or being taken by humans," he said.

"Have a look at the ant. If it's not black and it's quite active, then it might be an Argentine ant."

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