Ant pest found in central city
Argentine ants have been discovered in a fourth area of Christchurch as part of a Department of Conservation (DOC), ECan and Christchurch City Council campaign to identify infestations.
DOC entomologist Alison Evans says the new find, in the central city, is likely to have been there for some time. Business operators and others who work in the centre of town are being asked to keep an eye out for them and call DOC on 379 9758 if they think they have these ants living on the premises. Professional help is needed to control Argentine ants.
The ants are 2mm-3mm long and a light to dark honey brown colour, whereas native ants are usually black. Unlike Darwins ants, they don't smell when squashed.
Argentine ants have been found throughout the North Island but Christchurch agencies have banded together to try and reduce numbers and prevent their spread to other parts of the city because of their potentially devastating effect on native biodiversity.
"In gardens and the bush they can displace native insects, compete with nectar-eaters and will attack nesting birds," Dr Evans says.
"In households and businesses they can be a tiresome nuisance, streaming across surfaces and making their way into cupboards, containers and even fridges." Dr Evans says it is not known how the ants travelled into central Christchurch but it is most likely that it was associated with transport of freight or rubbish. "Female Argentine ants cannot fly but make highly effective use of human modes of transport," she says.
Despite nearly 200 calls about ants to DOC over the summer, this is the only new Argentine ant infestation identified since the start of the publicity campaign.
"Most calls have been about Darwins ants, which are very similar in colour, and we have even had calls about ants that we did not know existed in Christchurch," Dr Evans says.
A co-ordinated control programme is being organised with effected central city businesses, before the ant population gets a chance to expand further. Workshops are also being held to update pest-control operators around the city.
"Experimental control at the three other Argentine ant sites (in Riccarton, Sockburn and Hornby) has been highly effective, with the two oldest sites reduced to almost nothing this year," Dr Evans says. "If we can keep on top of this problem in the city and teach people how to use the new bait it will be well worthwhile. We don't want to get to the stage that we are trying to remove Argentine ants from the Port Hills or Banks Peninsula, where they would have a very damaging effect on native insect, plant and bird communities".
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