Northland is among New Zealand’s most wasp-infested regions, with 88% of participants in a new national survey reporting that they see wasps “very frequently” here.
The Pest Wasp Survey Preliminary Report, released last month by the Moths and Butterflies of New Zealand Trust, ranks Northland in the top three regions for invasive wasp activity, alongside Tasman (98%) and Marlborough (92%). The findings confirmed wasps were widespread, increasingly aggressive and ecologically damaging.
Founding trustee Jacqui Knight MZNM said the survey would help protect New Zealand’s native butterflies such as monarchs, red admirals, and white cabbages, and hoped it would build enough support to get wasps added to the Predator Free 2050 target species list.
The trust had wanted to reach beyond its usual butterfly and moth (lepidoptera) community to gauge public awareness of wasps, and the response had been amazing, she said.
The survey, from June 26 to August 14 this year, drew 1055 individual responses and input from 100 conservation groups. Most participants believed wasp control should be a priority, with increased funding. Concern was highest among people who regularly monitored wasp activity.
Wasps were seen as the greatest threat to insects (36.7%), followed by the honeydew (sap sucking insect) ecosystems (23.8%), birds (14.7%), fauna such as bats and geckos (11%) and forest regeneration (9.9%).
While humans weren’t listed as a major concern, the report flagged health and safety concerns over dangerous DIY nest destruction methods, including petrol and fire.
Despite widespread concern, the survey revealed gaps in public knowledge. Restoration groups showed better species identification and control skills but a third of individual respondents could only identify one or no wasp species.
Knight said many people couldn’t tell the difference between a wasp and a bee.
We don’t want people just killing everything off that looks like a wasp - that’ll just destroy the whole ecosystem,” she said.
New Zealand is home to between 2000 and 3000 species of native wasps, which are ecologically harmless but five species of invasive wasps — German and common wasps, and three paper wasps (Asian, Australian and European) — are not.
Knight said all five hunted caterpillars to feed their young and other insects. One survey respondent had even seen wasps kill a baby bird.
Studies of wasps in South Island honeydew ecosystems revealed they’ll even fly their competitors such as native ants away from the food source.
At Northland’s Opua Forest, Bay Bush Action Trust’s Brad Windust filmed wasps devouring a live wētā.
“It’s not just wētā, but also stick insects, caterpillars, pūriri moths, and weevils,” he said, describing the situation as a “biodiversity crisis”.
“Insects are the backbone of our ecosystem - that’s where conservation needs to start, and we’re (also) calling on the Government to add wasps to Predator Free.”
Windust warned that without addressing insect loss, efforts to protect native birds like the grey warbler, tomtit or tūī would be undermined by food scarcity.
The survey showed control methods varied with nest destruction most common (43%), followed by traps (23%) and Vespex bait (13%).
There was strong public support for a more coordinated approach. Nearly three-quarters backed a multi-agency programme, and 43% preferred a single lead agency. Many also called for wasp management to be integrated into broader conservation efforts, such as Predator Free 2050.
Northland Regional Council (NRC) does not currently manage wasps under any formal pest control programme. Responsibility for dealing with nests falls to individual landowners, while nests on public land may be referred to the Department of Conservation (DoC) or the relevant district council.
NRC said paper wasps can build nests at a density of more than 200 nests per hectare. The council advised tackling small infestations using insecticides available from garden centres and supermarkets. However, if multiple nests were present or access was difficult, it was best to contact professional pest control services.
The council also warned that wasps could become aggressive if disturbed and are capable of stinging repeatedly.
DoC estimates invasive wasps cost New Zealand more than $130 million annually, affecting sectors such as farming, forestry, horticulture, and apiculture, and posing risks to health and recreation.
Predator Free New Zealand Trust chief executive Jessi Morgan said while the 2050 initiative primarily targets mammalian predators, other ecological threats aren’t being ignored.
Sarah Curtis is a news reporter for the Northern Advocate, focusing on a wide range of issues. She has nearly 20 years’ experience in journalism, most of which she spent court reporting in Gisborne and on the East Coast.