What's the big deal about wasps?
- Birkenhead Butterflies
- Apr 17
- 6 min read
Introduced social wasps are decimating our wildlife
April 2025
The one thing I noticed immediately upon moving into the new digs was the wasps. I am used to wasps at the old house a suburb over, but here there are swarms of the horrible things. That's why number 4 of the garden project plan was pest annihilation.
4. Need to identify and remove pest animals ... Wasps will reduce caterpillar numbers substantially.
When I say wasps, I mean the accidentally introduced social wasps from Europe, Asia and Australia. Aotearoa New Zealand has its own native species of wasps. Most of them are small and unobtrusive and none of them try to sting you or decimate the butterfly and moth populations. So when I say wasps, I mean the mad, bad guys. And there are a lot of them here. I had a full house playing wasp bingo within a week of arriving at the new abode.
The summer of 2025 has been hot and dry, giving wasps a perfect climate to breed, according to University of Auckland's Professor Jacqueline Beggs, meaning butterfly numbers are down wherever the climate is conducive to wasps. Wasps are the number one reason we raise butterflies in "castles" - pop up boxes of tight mesh that allow light, air and water through, but not predators. But you can't raise butterflies in captivity if there are no eggs or caterpillars to give safe haven to.
Vespula Wasps
There are two types of vespula wasp, the common wasp and the German wasp. Really it makes no difference knowing which has come to annoy you, as their behaviour is the same. Apparently New Zealand has the highest density of vespula wasps in the world. Lucky us. This is because the wasps were accidentally introduced from Europe, but none of their natural predators were. Guess where the world's biggest wasp nest was found? Auckland.
They are problematic not only from a ruin-your-picnic point of view, but also because they both prey on and out compete native wildlife for food. Bird, insect and lizard populations are all directly affected by vespula wasps taking vast amounts of honeydew and they prey on insects in significant quantities. They are arseholes to honeybees and take out hives. The Department of Conservation reports wasps even killing new born baby birds, which is pretty much the epitome of evil in Aotearoa.
Paper Wasps
There are three types of paper wasp in New Zealand and it does make a bit more of a difference knowing what is around, but not a whole lot. European paper wasps like to go big, because they are not going home. They apparently develop more quickly, are more likely to have large nests and to nest inside a house. The European paper wasp has similar markings to Asian paper wasps, except with go faster stripes. If you look at the photos above and below, you can see the European has a couple of extra markings at the top of its back.
The third type of paper wasp is easier to identify. They are the same shape as the Asian and the European, but they are brown, rather than black and yellow. Say G'day to the laid back Australian paper wasp.
For the butterfly gardener it's the paper wasps we have to watch out for. They are less aggressive than vespula wasps towards us, but still have an enormous effect on native insects. What is worse, there is no effective way to get rid of them, because they don't eat carrion and therefore can't be baited.
They significantly impact butterflies and moths by taking a high percentage of their caterpillars to feed to their larvae. They will also take live butterflies. I had the misfortune a couple of times to witness Asian paper wasps ripping the wings off monarch butterflies to stop them escaping.
European tube wasp
This is the wasp that nobody talks about, also known as the European potter wasp. This is because they are smaller, do not work together to create colonies (social) and their sting is less painful than the vespula wasps'. However, each female will take up to 20 caterpillars to feed her young. When each butterfly lays hundreds of eggs, it doesn't sound much, but when it is one more introduced species preying on native lepidoptera, who already have native predators and social wasps to contend with, it all adds up.
What can we do about them?
The most important thing is to get rid of any wasp nests you find. If you are seeing wasps there's a nest within a couple of hundred metres. Here in Auckland, Auckland Council will remove vespula wasp nests on public land. I reported a nest under a hedge at the entrance to a Hillcrest reserve and they had a contractor out within two hours of me reporting it.
If you are renting, your landlord should get rid of a nest on the property and if it's your place, then you'll need to pay an exterminator or gird your loins. Vespula nests are apparently best taken out after dark, but be smart and make sure your torch has red cellophane over the end, because these wasps will attack you and will fly along your torch's beam if it's white light. Special poisoned powder can be placed at or puffed into the entrance to a vespula nest, meaning the wasps entering will take it further into the nest and that will kill the colony. I haven't had to take out one of those nests before and if it is during the peak activity of a nest in summer, I'd be very wary.
Alternatively there is a poison for vespula wasps, which is only effective at the peak of the insect take, called Vespex. This needs a registered, approved user, because the poison is serious stuff, and given the number of wasps around here, I'm going to do the training to use the bait. It costs though, but I reckon it must be similar to bringing a professional in. It definitely costs less than putting my car into the mechanic when it's making noises like a nest of angry wasps. Vespex should take out multiple nests in an area and the best part is that you don't need to find out where the nests are.
I have had to take out quite a few paper wasp nests and the best time is dusk. They have settled for the night, there are no flying insects likely to get caught in the cross fire and you can still see what you are doing. I hit them with fly spray and then run away as fast as I can. Apparently they wouldn't chase me, unlike vespula wasps, but I don't stick around to see if the experts are right. I come back the next morning and knock down and stomp on the nest, so it can't be used.
What about other methods - traps, for example?
Scientifically, the data says don't bother. You can't remove enough vespula wasps to affect the operation of the nest. That doesn't stop me trying, but nothing was interested in my home-made bottle traps and its now too late for this year. I read a study that said sardine cat food was the best bait for a trap when vespula wasps, which will eat carrion, are taking caterpillars. There are a lot of caterpillars taken before something like Vespex can be used and I'll do anything to save them.
Usually in September when both vespula and paper wasps are just setting up shop, I catch them with fishing nets from the $2 shop and stomp on them. I figure that given that the worker wasps haven't really come out yet, vespula wasps around then are important to setting up the nest and I might even bag a queen. Paper wasps also start small and if I take out one of a pair, it might mean a non-viable nest. If I take them both out, that's definitely one less nest. Also, stomping on wasps makes you feel like you are doing something to solve the problem and it's a positive way to vent your anger. Win-win.
I was busy moving in September last year and didn't have the time to run around swearing at wasps, but I got the whole family and visitors to capture wasps when they were at our place once we'd settled in. If it saves just one butterfly, I'm up for it.
I hate wasps. (Not you, native wasps. You are balancing the ecosystem, so good on you). I tend towards the live-and-let-live end of the scale when it comes to bugs and I avoid the use of poisons, but introduced wasps trigger all out wrath in me.
In all seriousness, if we lose our insects, we lose our ecosystems and our food crops. They are in depressingly big trouble and introduced wasps are pushing vulnerable species across most of the country closer to extinction. We have to take them seriously as an introduced predator and we have to take them out.
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