Anterhynchium tamarinum update

December 2025

One of several more Anterhynchium tamarinum in the garden

Christmas Eve is not a good time to generate more work when you are trying to get plants into the ground last-minute, but it was a warm afternoon and I caught three more Anterhynchium tamarinum on the same swan plant in my garden in quick succession. They did not seem so orange as the first one I caught, so I was a little cautious of assuming they were the same new-to-New Zealand species without a corroborating ID, but suspicious enough to take some photos of the third wasp alive and undamaged before it too suffered the fate of all non-native wasps in my butterfly garden.

I wondered about catching the last alive, but no one is going to be interested on Christmas Eve and it really goes against the grain to feed something that undoes the work I've undertaken to establish a safe enough space for Lepidoptera. MPI confirmed they that feed predominately on Lepidoptera larvae.

Anyway, I emailed the case officer at MPI, bagged the specimens - these ones more stomped than the first - and popped them in the fridge, alongside the extra Christmas food and drink. I think there may have been another wasp flying around at the time, but I haven't seen one since, despite being very concious about keeping my eyes open.

I find it interesting that I saw three in just a few minutes at the same location in the garden when MPI told me they are a solitary, nest cavity constructing wasp. Larry, who spotted the very first Anterhynchium tamarinum in Aotearoa, re-visited his old home in early December after my first sighting and saw three more wasps at the same Glenfield location. On 23 December there was the first iNaturalist-recorded sighting in Beach Haven, which has been confirmed by MPI. That wasp was after monarch caterpillars, which is worrying. There can be no doubt after this that they are breeding in the Kaipātiki area of the North Shore.

MPI emailed me back after the public holidays with a really interesting update. As they suspected, the hornet response had resulted in more sightings of Anterhynchium tamarinum and they were able to sequence the wasp's DNA.

With the information they currently have, the current expectation is that it has indeed been established since at least 2021 and the biosecurity risk is low. They anticipate Anterhynchium tamarinum will have a similar impact as the European tube wasp - another non-native solitary potter wasp - although I note A. tamarinum is bigger. They are not a threat to people, they are pollinators (as are our native wasps too) and are part of a sub-genus that are seen as beneficial in their native range.

Studies show Anterhynchium spp. vary in their feeding habits with some predating on a wide range of host species, and others specialising in hunting one species.

Another specimen recently found in Auckland had been carrying a caterpillar, the caterpillar has been identified as belonging to the Crambidae family, many of which are significant agricultural pests.  

I am surprised to hear that Crambidae - grass moths - are seen as pests - given that, of the 24 species I have seen, 20 are endemic species (found only in New Zealand), one was native (found in other countries naturally too) and only three were introduced. I guess it goes with the territory that the Ministry of Primary Industries would be more concerned with creatures that affect the profit margins of farmers than protecting our native flora and fauna. One could only speculate if the response would be different if Biosecurity sat under a different portfolio, such as the Ministry for the Environment. Despite that curve ball, I am very grateful for the detailed update I received. It was generous and thoughtful and a lot more scientific than my layman's paraphrasing.

So I am off to bin the samples in the fridge, whilst I wonder if, whilst solitary, Anterhynchium tamarinum are gregarious (meaning that they will nest in the same area as others, like solitary bees do) because of the numbers both Larry and I have seen in one place. They have been here for three years at least, given Larry's initial sighting, but it is only in the last month there have been any other sightings, so that's another puzzle. And what is it about Glenfield that makes it new wasp/hornet central, given it is an inland suburb away from the airport, port and those storm winds that blow insects in from Australia?

I know practically nothing about wasps, other than it is not fun to have a vespula wasp in your Coke can when you take a swig, so I look forward to hearing the answers to these questions as they get figured out. This is certainly an interesting time and place to live for those with an interest in insects.