Can NZ ever be free of the 'vulgar' wasp?

The common wasp, or Vespula vulgaris, has long posed a headache for conservation efforts in New Zealand. Photo / File

They're a nasty nuisance that plague our picnics and aren't afraid to give us a painful sting. But, in our natural environment, the common wasp causes a far bigger problem. Can we ever be rid of the black and yellow scourge? Science reporter Jamie Morton spoke to Victoria University's Professor Phil Lester, who has just published his book The Vulgar Wasp: The Story of a Ruthless Invader and Ingenious Predator.

First, can you provide a potted history of the common wasp, Vespula vulgaris, here and around the world?

The common wasp was first observed in New Zealand in the 1920s, but didn't have a confirmed establishment and become abundant before the 1970s.

It has also become established in South America and Australia, but also in colder places such as Iceland.

Its cousin the German wasp, which established in the mid 1940s, has an even wider distribution and has established in South Africa, North and South America, Australia, Iceland, and quite a few remote little islands.

Both species seem to like human goods for hibernating in, which is why they have likely been moved around a lot and not the many other Vespula wasp species.

What stirred you to write this book?

Two main reasons.

First, wasps, ants and bees are really fascinating.

Despite having a tiny brain they are tremendously smart.

Wasps can learn to recognise human faces, with a high level of differentiation even when the faces are turned upside-down.

Their venom is this fantastic cocktail of chemicals that dissolve cells, enhance nerve firing and pain, and mark you as an enemy for others to find.

It still amazes me that a tiny little amount of venom can be lethal.

Second, wasps are a great example of a pest and biological invader.

Around the world and within New Zealand over the last few years, there has been a growing movement to reconsider exotic species and biological invaders.

Should we really try to control or eradicate species, or perhaps just accept them as part of a "new world"?

I think accepting species is probably fine if they don't do "harm".

Wasps, however, do substantial harm to our biodiversity, economy and health.

And so, what should we do about them?

What is the best control approach?

Every approach has its risks and benefits.

Most Kiwis probably see invasive wasps as merely a nuisance or as something that might sting them. I still have nasty memories of disturbing a wasp nest as a boy. But do you feel there's a general appreciation for the largely unseen toll they've wrought on nature?

I suspect a lot of people probably don't see a lot of wasps.

Many city-dwellers will see the occasional wasp but probably not ever experience the abundance they attain in many areas of New Zealand.

Many beekeepers will be intimately familiar with wasps and their effects.

The effects of wasps on bees and their pollination represents the bulk of the annual $133 million cost of wasps.

My greatest concern, however, is the effects of wasps in our native forests.

We have a million hectares of honeydew beach tree forest in the upper South Island, which has massive wasp densities of up to 40 nests per hectare.

Most people will have no idea of how many wasps we have in these forests unless they walk through that forest, to see and hear the drone of wasps in late summer and autumn.

The tiny jaws of these multitudes exert a massive predatory effect on our native biodiversity.

At the same time, do you think Kiwis realise that there are different wasp species - including native ones we're trying to save?

I'm sure most Kiwis are completely unaware of the benefits and diversity of wasps we have here.

The common wasp was first observed in New Zealand in the 1920s, but didn't have a confirmed establishment and become abundant before the 1970s. Photo / File

Most species in New Zealand are solitary.

They are often "parasitoids" that specialise on killing pests of our agriculture and horticulture.

By controlling pests, many these parasitoid wasps effectively contribute millions of dollars to our economy and mean that we don't have to use pesticides as much.

Whatever we do to manage social wasps, we should ensure as little impact as possible on these parasitoids.

The Wasp Wipeout campaign raised $55,000. Was that heartening to see and does it show that we do really care about getting rid of these pests?

If you live with wasps in an area like Nelson, you realise what a problem these pests can be.

Many people in these waspy areas are enthusiastic to control or even eradicate them.

With the development of the bait Vespex, we now have a great tool for wasp control at the scale of many hectares.

Is there any hope of wiping them out completely? With climate change coming, is this a pest we're simply now stuck with?

The widespread use of something like Vespex will control wasps over the short-term.

But queens will reinvade areas where wasps have been controlled.

The bigger that area of control, the longer it will take for wasps to reinvade.

Though wasps can fly long distances and reinvasion might be very fast.

Within the National Science Challenge we are using wasps as a model pest system for investigating next-generation pest control methods.

Research groups around NZ are working towards the development of control methods that could eradicate wasps from the entire country.

I think that would be a fantastic outcome.

Climate change will have some interesting and varied effects.

Wasps do well when the weather in spring and summer is warm and dry.

So expect more wasps in areas that become increasingly warm and dry with climate change.

But extreme weather events such as heavy rain and flash-floods, which occur with tropical cyclones, are bad news for underground nesting animals.

We'd generally expect fewer wasps in areas that suffer from these extreme weather events.

What can wasps teach us about pest control and the Predator Free NZ mission?

Many of the technologies being discussed for the Predator Free NZ mission are also being discussed for wasps.

For example, the potential and ethics of gene drives, or genetic modification, is being discussed and will inform the Predator Free NZ mission.

Pests are pests, whether they are large and furry or small and sting.

We very much need the New Zealand public to engage and contribute to the discussion about the right way to manage them.

If there's a take-away message from your book, what is it?

New Zealand is just like everywhere else around the world.

We are now a composite of native and introduced species.

Many of those introduced species are not damaging or a problem: they cause no identifiable harm and need no active management.

But some species, despite being wonderfully fascinating and demonstrating some amazing behaviours and physiology, require management for the benefit of our economies, health and biodiversity.

I'd really like people to see the many sides of wasps and their potential management options.