Why We Need to Get Rid of Wasps
By Annie Hill
The original article in Russell Lights | Ngā Mārama o Kororāreka March edition 2025
While I might have my work cut out convincing people of the virtues of weka, and that sweet little hedgehogs are a nightmare for our smaller wildlife, I think we can all agree that we don’t like stinging wasps. There is no doubt that Aotearoa New Zealand would be a better place if the German and common wasps went back whence they came.
Featured photo: D.Sikes
A Recent Arrival with a Big Impact
Surprisingly perhaps, these short-tempered, stingers—the bane of picnics, BBQs, and particularly trampers—haven’t been here that long. German wasps arrived in 1945, and common wasps even more recently in the late 70s. Once established, they settled down and spread with a vengeance.
They look very similar: common wasps are around 12–17 mm long; German wasps can be larger, and the queens are up to 20 mm. (I would have thought them bigger than this, probably because they can be so literally ‛in your face’.)
Identification of The Invaders
Both species are social wasps, which is one of the reasons they’re such pests. Unusually, we have no endemic social wasps; they all live solitary lives. There are literally thousands of species of native wasps, generally small, which parasitise other insects and are a necessary and important part of our ecosystem. Some of them are flightless and probably, if noticed at all, would be mistaken for an ant. Like so many small creatures on this planet, they live out their varied and blameless lives unobserved, ignored, and often not even classified.
On the other hand, we know lots about the black and yellow ones. Between them, the two species can be found naturally in Europe, Northern Africa, temperate Asia, India and China. As well as being extraordinarily adaptable, they must be successful stowaways, because they’ve invaded North America, Australia, South America and South Africa, as well as these motu, and you’d have to be an expert to identify which species ended up where. As well as being quite difficult to tell apart, German and common wasps share a lot of traits, so I may as well treat them the same.
A Major Threat to Native Wildlife
Wasps eat carrion, live arthropods, fruit, honeydew, and processed human food and rubbish. This versatility enhances their effectiveness as invasive species, but the common wasp appears to have the edge and has been ousting the German wasp from the beech forests of the South Island. They are apparently more effective at dealing with honeydew, which they collect more rapidly than German wasps. Because honeydew often ferments, the slow pace at which the German wasp collects it makes it susceptible to the effects of the fermentation, which reduces their effectiveness as foragers. Common wasps are also more aggressive.
They’re found in enormous concentrations in some of our beech forests, in far higher densities than anywhere else in the world. In summer, their biomass may exceed that of all the birds, mustelids and rodents put together, and up to 370 wasps have been counted on one square metre of beech trunk. Sometimes, all you can hear in the forest is their buzzing. For five months of the year, wasps consume more than 90% of honeydew!
The Devastating Effect on Insects and Birds
Actively predatory, wasps particularly target insects in order to provide protein for their larvae. Their collective assault on insects is in direct competition with our native birds, and the predation rate of wasps on some native invertebrates is so high that most of them are wiped out through the wasp season. They also occasionally kill and consume nestlings.
Honeydew is an important food source for both insects and birds, and even if wasps didn’t consume so much of it, our native animals are unlikely to actively compete with so many aggressive and stinging creatures.
The Life Cycle of a Wasp Nest
The life cycle of wasps is not dissimilar to that of honey bees. In spring, queens emerge from hibernation and make a new nest. Over summer, they continue to expand the nest and create increasing numbers of workers. In the autumn, the nest produces males (drones) and females (new queens) which can then reproduce. Come winter, the new queens fly away from the nest and hibernate and the nest usually dies.
Sometimes, however, in our warm climate, they can survive the winter and this can lead to absolutely enormous nests being formed over a number of years. The world’s largest recorded wasp nest was discovered at Waimauku (near Auckland) and was 3.75 metres tall and 1.7 metres wide.
Controlling Wasps with Predator Free Russell
It would appear that wasps are well established and have little to worry about. Generally, householders and landowners have to deal with them as best they can, but wasps don’t take kindly to having their nest disturbed, and, unlike bees, can sting humans repeatedly.
Recently, Predator Free Russell received a generous donation of wasp killer that can be laid at the mouth of a nest. The workers take it into the nest and it’s soon spread around, with lethal effect. A large wasps’ nest is a fearsome prospect, but if PFR is on your land, attending to traps and bait stations, team members can be asked to deal with your wasps’ nest, too.
Let’s hope they get another donation, so that they can keep on offering this service! Wasps are annoying and dangerous, and it’s in the best interests of our native animals, and ourselves, to control them.
