The establishment of the yellow-legged hornet would trigger an economic and ecological crisis. The yellow-legged hornet - known as the Asian hornet overseas - is an apex predator that can kill 30-50 honey bees a day. They not only invade a hive but also engage in “hawking”, capturing bees on the wing just metres from the hive. Under sustained attacks, bees will often just stay in the hive, unable to leave, leading to starvation and collapse. This extra stress reduces bee and colony immunity making them more susceptible to pests and diseases. Not only affecting honey bees, but also our native insects having evolved without such predators, and are poorly equipped to defend themselves. With 28 species of native bees –27 found nowhere else – the risk to our biodiversity is immense.
We can see exactly what will happen thanks to the accidental introduction of the German and common wasps in 1940s and 1920s respectively. We can see how easily the hornets could spread, and it is terrifying. German and common wasps spread quite quickly and by the 1970s had colonised most of NZ, from Cape Reinga to Stewart Island. We now have some of the highest densities of these wasps in the world, thanks to the lack of natural predators and favourable climate. We’re the only country that lists wasps as one of the top five causes of hive loss in the International Colony Loss Survey. If hornets get a foothold, they would be so much worse.
The honey industry would be affected at least as badly as when varroa were introduced 25 years ago, which increased the costs to maintain each hive, the increased annual loss of hives and beekeepers leaving the industry. The biggest threat to us though is pollination. Pollination adds about $2 billion annually to the NZ economy; insects that pollinate our crops include honey bees, bumble bees, native bees and others. Crops that depend upon pollination include fruit & vegetables, seed crops, and pastures and their ancillary industries like grazing – dairy, beef and sheep. MPI’s SOPI report projected over $8 billion annual export revenue from horticulture up to June 2025; almost half of which is kiwifruit, and a billion dollars from apples and pears. These pollinating insects enhance quality and quantity of fruit set, without which our horticulture industry would struggle to remain competitive
Not only could a disruptive pest like this affect our economy but it will upset our biodiversity and reduce so much of our native fauna, which could then affect our native flora too. Not to mention that hornets are quite aggressive, with most deaths overseas from hornets caused by anaphylaxis. Their stings are longer than a honey bee’s and the traditional beekeeper’s suit doesn’t provide sufficient protection. All in all, any cost to ensure that they don’t gain a foothold in Aotearoa would be money well spent - we don’t want to look back in ten years and question what else we could have done.
MPI are continuing to ramp up surveillance and trapping, so far they’ve only been found in Glenfield. A technical Advisory Group (TAG) has been set up with industry experts and advisors from overseas. As an AP2 with NZBB (New Zealand Bee Health & Biosecurity) and having participated in other honey bee biosecurity protection, I’m aware of the incredible work that goes on behind the scenes.
It is up to every Aucklander to check for nests and hornets and to report anything suspicious to MPI on 0800 809 966 or report.mpi.govt.nz
Homemade traps in your garden can be good way to check for hornets but please careful of bycatch; if using a sweet lure like fruit juice, sugar-water or jam dissolved in water –add beer, vinegar or yeast to deter bees. We only have a year or two to eradicate them before they become established here. With a concerted coordinated effort it is achievable – and a timely reminder just how fragile and precious our ecosystem is here in Aotearoa.
Ken Brown
Apiculture Tutor, Land Based Training Ltd
President Auckland Beekeepers Club
