Following the discovery of a “frighteningly large” wasp nest in Martinborough, Victoria University entomologist Phil Lester has warned there are likely to be more in the region.
The nest was found last week by an academic on a geology field trip with students at a farm near Te Muna Rd.
Lester said it was situated between the farm and a stream, nestled in a pine shelter belt.
He believed the nest had been there for at least 18 months without being observed and it is likely not the only one.
“I suspect that there are more of those around that people just don’t come across,” he said.
The 1.8 metre long, 1.3m wide and 96cm tall nest was home to between 100,000 and 200,000 Vespula germanica – German Wasps.
“They are big predators,” Lester said.
“A nest that size will eat tens of kilos of invertebrates, many of which are native.”
German wasps are also known to attack honeybee hives, and Lester said they are a “big problem” for a lot of beekeepers.
He explained that the German wasps raid bee hives, kill the worker bees, eat the larvae, and then steal the honey.
The ideal conditions for nests to grow at a larger scale include dry and warm conditions, and most nests start to be formed in springtime.
Warm, dry, and mild winters allow for the hives to keep growing, while wet areas and seasons are likely to kill nests.
“This was the biggest one I’ve ever come across and had to work with,” Lester said.
The nest was dismantled, and the wasps killed, but it wasn’t an easy task as they “became quite angry”.
Vespex wasp bait is the recommended method for kill wasps as it is not at all attractive to bees and is considered to be “very low risk” to birds, pets, and people.
“You can put it a reasonable distance from the nest and the wasps will find it and take it back to the nest,” where the bait will be shared around the nest, effectively killing the wasps, Lester said.
He didn’t recommend that people go near nests. Vespex does require registration to use but is also recommended by the Department of Conservation [DoC] for effective control of wasp colonies.
Over the coming months, Lester will be studying the nest, which he described as “really large and very successful”.
“One of the things we’re interested in is why do some nests become so big? Is this likely to happen more often in the future?’”
Lester and his team will be studying population genetics within the nest and whether the presence of multiple queen wasps contributed to the substantial number of worker wasps and the size of the nest.
According to DoC, New Zealand has some of the world’s highest densities of German wasps as there are no natural predators, winters are generally mild, and there is plenty of food for them.
