DOC takes the bait further

Summer is around the corner along with the potential for wasps to make a nuisance of themselves. So Stuff’s Wasp Wipeout is back and gearing up to take out every barbecue’s worst nightmare.

Starting out as a local effort in the Nelson–Tasman region in

2016, the wipeout project has spread just like the invasive wasp species it targets to occupy most of New Zealand.

This year the project is taking on most of the South Island, as well as for the first time parts of the North Island, and will include harder-to-target paper wasps nationwide.

Department of Conservation (DOC) Wasp Wipeout project lead Adam Riding said he ‘‘couldn’t be more excited’’ about the expansion of the programme, including the creation of a national coordinator role.

He said there were ‘‘early indications’’ of wasp numbers, but the complete picture wouldn’t be clear until towards the end of December.

‘‘The plan at this point of every year is to expand on what we’ve done in previous years.

‘‘[In] the Nelson–Tasman region, which has the most history of the project, we do already hit most of the top spots.’’

He said it was likely DOC would be spreading further out in the Tasman region than in previous years, but where exactly was yet to be determined.

Stuff, DOC, the Tasman Environmental Trust and Conservation Volunteers New Zealand have combined forces to track wasp populations and, at just the right time (usually mid to late summer depending on wasp activity and numbers), to hit the great outdoors with bait.

The protein-based bait is carefully designed and administered to target wasps with as little risk to other animals or insects as possible. The active ingredient, fipronil, is at a concentration of

0.1 per cent, a lower concentration than the same active ingredient found in common flea treatments for cats and dogs.

Large populations of wasps, which have no natural predators in New Zealand, can put native insect populations in a tailspin.

Two types of wasp targeted

Wasp Wipeout has spread its wings and is targeting two different types of wasp. But why didn’t the project target both types from the start?

It all comes down to the dining preferences of the otherwise quite similar species.

Since 2016, a partnership of Stuff, the Department of Conservation, Tasman Environmental Trust and other environmental groups has been taking on one of the worst predators in New Zealand, hitting beech forests with Vespex bait.

The bait is up to 98 per cent effective at clearing out a specific type of wasp: the Vespula group. Vespula is an umbrella term that covers two wasp species in New Zealand, the common wasp and the German wasp.

In the average wasp encounter, the differences between the common and German type are largely cosmetic: the German wasp is a little larger and more yellow than the common, and it established itself in New Zealand earlier.

However, to be safe, the bait stations are attached to trees in a way that makes them difficult for most animals to reach.

Because the poison is effective against any insect that might find it, it is removed within eight days to minimise the chance of poisoning non-target insects.

Bees don’t take the bait as they don’t eat protein.

A 2017 study found that in just four days Vespex reduced wasp numbers by 94 per cent, and longer exposure resulted in a reduction of up to 98 per cent.

New Zealand, and particularly the Nelson Lakes region, has some of the highest wasp densities in the world, with up to 40 nests per hectare of forest and a biomass that dwarfs rodents, birds and stoats.

The German wasp was first spotted in a Hamilton airforce base in 1945, and quickly established itself as an apex predator. The common wasp took a little longer to set up shop, but became just as much of a problem in the 1970s.

Both the different Vespula bandits have a common habit that makes them prone to baiting, which is that they are opportunistic feeders. Once they start eating protein in mid-to-late summer, they are happy to strip the meat off road-kill to bring back enough food for the larvae in the nest. Wasp Wipeout takes advantage of this by putting out the protein-based Vespex bait for about a week during the early stages of the protein-eating phase.

Unfortunately, this highly effective poison is helpless against paper wasps which hunt live insects, and don’t take bait. They are also far more likely to be found hanging off your garden fence, rather than buzzing about in beech forests.

Despite the up-to 98 per cent effectiveness of Vespex at clearing wasps out of even the highestpopulation areas, the poison needs to be readministered every year as a queen wasp can fly vast distances, up to 70 kilometres, when searching for the perfect spot to build her nest.

Just one queen can reinfect an area to the tune of thousands of individual wasps, which then strip the forest of honeydew, nectar and insects.

Unfortunately, paper wasps are trickier to target, because unlike the more opportunistic vespula (common and German wasp) species, paper wasps only eat live insects. This, as well as a preference for more urban areas, means tackling paper wasps has to be a communal effort, usually involving a can of spray.

The annual cost of wasps to New Zealand’s economy has been estimated to be $130 million, mostly thanks to wasps systematically destroying beehives, taking the legs out from under honey producers and having a flow-on effect on farmers.

The costs to the environment are much higher, with multiple studies showing that the overwhelming presence of wasps, which have no natural predators in New Zealand, can put native insect populations in a tailspin, and effectively take out the food sources that every native animal relies on.

Vespex wipes out entire nests in one hit thanks to the way wasps eat. Although the adult drones are the ones gathering all the honeydew and insects from the bush, they actually have very poor digestive systems and can’t digest any of it themselves. Instead, the wasps bring everything back to the nest and feed it to the larvae, which then feed the adults with a pre-digested meal.

When wasps take the proteinbased Vespex bait to the nest and feed it to the larvae, they effectively wipe out the next generation of wasps.

Wasp Wipeout is a collaboration between Stuff, the Department of Conservation, the Tasman Environmental Trust and Conservation Volunteers New Zealand. Donations can be made at: givealittle.co.nz/cause/ wasp-wipeout-1.

FAQ

What is Wasp Wipeout? It is a community-led conservation project aimed at significantly reducing wasp populations in New Zealand. It’s supported by as well as the Department of Conservation, Tasman Environmental Trust, Conservation Volunteers NZ, scientists and, hopefully, you. How does the project work? There are several ways of helping. You can donate money to support existing and new wasp control operations at various locations around New Zealand, including national parks and popular reserves. You can volunteer for specific projects. Or, you can DIY by doing your own wasp control operation in your community, street or backyard by joining forces with family, friends and neighbours. Link up on Neighbourly.

Where does my money go? All donations go to the Tasman Environment Trust, which will distribute the funds to continue existing wasp control operations on public land like national parks and reserves, and support new ones around New Zealand. Why the focus on wasps? Anyone who’s had a wasp encounter knows how nasty they can be. The German and common wasps are major pests and pose serious threats to our environment, economy and wellbeing. The paper wasps are a threat to our native insect life, particularly butterfly caterpillars.

How do you control wasps? A protein-based bait called Vespex, developed in Nelson, is currently the most effective method of widespread German and common wasp control. Vespex is deployed in bait stations at a specific time — usually around midFebruary — once the wasps have switched to a protein diet. The wasps take the bait back to the colony and the nest is usually wiped out overnight. Paper wasps don’t take the bait however, so people need to spray the nests around their homes with an over-the-counter wasp spray available at most hardware stores.

But aren’t insecticides bad? Vespex is low-toxicity bait that’s not at all attractive to bees and is of very low risk to birds, pets and people. The main ingredient, fipronil, is found in many dog flea powders. Any leftover bait is collected and removed from the environment within a week. Vespex also has the support of the Department of Conservation, Landcare Research and the World Wildlife Fund.

What’s the goal? We want everyone to be involved in protecting New Zealand’s biodiversity.