The outlook is looking positive; we may have done it!
The yellow legged hornet (YLH) incursion, that was first detected last year, is coming to the end of the current season. Like many insects, the YLH has a defined lifecycle; meaning its activity, behaviour and reproduction is regulated by the seasons. At the beginning there were many unknowns, we didn’t know how the YLH would adapt to New Zealand’s climate and environment; this meant that there wasn’t a playbook that we could follow. We had a good idea how it would progress but were uncertain about when. Developments could be weeks ahead of expectations. We seemed to be closer to southern Europe rather than the cooler northern climes of UK and France in development.
A reminder of the lifecycle of YLH:
- A mated queen emerges from hibernation in early spring
- She establishes a small embryo nest, usually low to the ground and starts raising workers
- This nest develops into the primary nest roughly the size of an iceberg lettuce, through spring and early summer
- The colony builds a secondary nest, high up in trees, in mid-summer, they use both nests
- Late summer/autumn drones (boys) emerge and disperse away from the nest in search of a mate
- Weeks later, gynes (virgin queens) emerge
- Gynes mate and then hibernate over winter to emerge and establish new colonies in the spring
We had seen drones, some of which had travelled significant distances, but importantly no gynes had been identified in traps or any of the nests examined in the laboratory. This distinction is important, if queens had emerged, mated and then hibernated we would be ramping up the response next season.
It is for this reason that I’m cautiously optimistic that we are on the right track. I have been on the Organism Management Team (Hornet Death Squad) and have not killed a nest in over three weeks. At the time of writing this, we also haven’t seen a hornet in two weeks. Absence of evidence doesn’t prove evidence of absence, but this is where we’d hoped we’d be – looking for hornets and not finding them.
Some may say that they could be anywhere and that we could have missed them, but the teams that have gotten us this far are still setting traps, observing traps and beehives, setting and observing Vespex poison stations with the same dedication that they have since spring.
We mustn’t be over-confident; we must remain vigilant and ensure that there aren’t any hornets wherever we may be. While it could be possible that a small or weak nest hasn’t been detected, the search will continue until we can be sure that they are eradicated. It is important therefore that we all continue to look for hornets, even if it is unlikely we’ll find any. We need to be sure that they have been eradicated from the Shore and that they haven’t been accidentally transposed elsewhere in New Zealand. The teams have been working so diligently, competing with each other and themselves to be the best at their allotted tasks. I am proud of everyone on the team for where they’ve gotten us thus far. Also, the residents of Glenfield and Auckland who have been very supportive and helpful with the active response, and everyone else in Aotearoa who has monitored their gardens and neighbourhood.
Report suspected sightings of hornets or their nests
You can make reports:
- by calling our exotic pest and disease hotline on 0800 809 966
- by emailing us at info@mpi.govt.nz
- online at report.mpi.govt.nz – if you use this method, select the ‘suspected yellow-legged hornet’ option from the dropdown list.
Ensure you give your location when making reports.
Ken Brown; Beekeeping Tutor with Land Based Training Ltd. & President of Auckland Beekeepers Club
