Invasive wasps have been reported across Central Otago, with European paper wasps spotted building nests in residential buildings. 

Former Central Otago District Mayor Malcolm Macpherson posted on social media to ask what insect had taken up residence in his door. 

“A family of these guys occupy that hole in one of our door frames. They seem friendly - what species are they, and do they sting? 

“I wondered about paper wasps - we often see their little pear-shaped nests. This group seem to be cave dwellers. 

“There's usually one or two standing guard, and one or two sometimes sit at the opening and fan their wings - aircon? If I bang the door frame, a little gang emerges.” 

Former Central Otago District Mayor Malcolm Macpherson posted his resident wasps on social media. 

The insect was identified as the European paper wasp (Polistes dominula), which is considered an invasive species, and is successfully established in many countries outside of its natural range. 

A Department of Primary industries wasp information brochure says, like other paper wasps, this species can sting and be aggressive, but generally only when the nest is disturbed. 

“This wasp appears to be well adapted to urban settings, preferring to nest in enclosed spaces such as wall spaces, and thereby increasing its likelihood of being a public nuisance. 

“European paper wasps should be managed in the same way as other already established paper wasps. 

“Avoid direct contact with live wasps and call your local pest control agent if you require help with the destruction of a nest.” 

Many people commented, with a unanimous agreement, that Malcolm had to get rid of the pests. 

“No no no.. they are bad bad bad. They need obliterating.. full stop,” one person commented. 

“OK, OK, they be gone,” Malcolm agreed. 

Malcolm told The Central App his resident pests are no longer. 

“Mine all dead now - I hope.” 

Central Otago pest expert Patricia Hilton, from ALLPEST, says she started treating paper wasps three years ago in Alexandra and two years ago in Cromwell 

She says she just had her first one in Arrowtown this season. 

“Have been treating them since Nov 2020 but only started treating German wasp nests mid Jan 21,” Patricia says.

“They are definitely more common and spreading. 

“I am currently treating up to 10 wasp nests a week, currently a good mix of both German and paper wasp.”

Patricia volunteers with an outfit called WaspWipeout, who are using Vespex, a relatively new protein insecticide for german wasps throughout the country.

The project targets German and common wasp populations in late summer using the Vespex wasp baiting system that reduces wasp numbers by more than 90%.

According to the Department of Conservation, New Zealand has some of the highest densities of German and common wasps in the world. 

“New Zealand has several kinds of native wasps which have evolved here and have never become a nuisance,” a DoC statement says. 

“But five social species of wasps have been accidentally introduced since the 1940s and are classed as pests (German and common wasps, and three species of paper wasp). How to identify wasps. 

“Introduced wasps are a significant pest which harm our native birds and insects, and are a threat to human health and recreation. 

“This is because they have no natural predators here, our winters are mild and there is plenty of food for them.” 

Introduced German and common social wasps are very similar in appearance, and both have the characteristic black and yellow colouration. 

“Social wasps live as colonies in nests of honeycomb-like cells,” the DoC Statement says. “They form complex social groups and all members of a colony help raise the young. 

“The German wasp was introduced in the 1940s and the common wasp arrived in the late 1970s but is now widespread. 

“Both species live in large colonies, about the size of a football. These colonies can become huge if they manage to survive over winter. 

“German wasp nests are grey. Common wasp nests are brown. 

“The world's largest recorded wasp nest was discovered at Waimauku (near Auckland). It was 3.75 metres tall and 1.7 metres wide.” 

Residents are urged to destroy invasive wasp nests immediately. 

For more information, visit the DoC website by clicking here.

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