Kia Pākiki Canterbury – wasps and hornets

In this Kia Pākiki Canterbury podcast, Science Communicator Tom Goulter and co-host Associate Professor Adrian Paterson from Lincoln University interview Dr Mateus Detoni from Lincoln University.

They discuss Mateus’s work with bees, wasps and invasive species such as the yellow-legged hornet.

Kia Pākiki Canterbury is a monthly podcast presented by the Canterbury branch of the Royal Society Te Apārangi.

Transcript

Tom Goulter

Mateus Detoni is a behavioural ecologist whose research focuses on social insects, especially bees and wasps. He’s a lecturer at Lincoln University’s Department of Pest Management and Conservation and a research associate for Manaaki Whenua – Landcare Research.

Mateus, what does it mean to say that bees and wasps are social insects?

Dr Mateus Detoni

Ah, that’s a fantastic first question. Social insects – the appropriate name is actually eusocial insects or truly social insects – so when you think about wasps and bees and ants and termites, those insects are different from other insects in the sense that they live in colonies, right? So many different kinds of animals can live in big family groups. Humans do, dogs do, wolves do, lions do. But the social insects, they take that to a next step when it comes to biological organisation. They pretty much forgo the ability to reproduce individually. You usually have one individual in the colony who is able to reproduce, to lay eggs. That’s usually the queen in most cases. And pretty much everyone else in that colony, they work towards the survival of the colony as a whole. And this ability – or this biological characteristic to not lay your own eggs, not to reproduce yourself and outsource that reproduction to your mother, the queen – allows them to function as a collective, so they can specialise sometimes in terms of behaviour, sometimes in terms of even morphology, so the way the bodies are shaped, to achieve excellence in doing whatever they’re doing.

So when you have individuals who are specialised at getting food, they’re probably going to be better than other species of animals where an individual has to get food and defend themselves and defend their brood and watch out for predators and things like that. So in a social insect colony such as a beehive or a wasp nest, usually, at least at a behavioural level, you’re going to have those specialised individuals who are very good at what they do. And that works because they’re all working together to make sure the colony survives, not necessarily that each individual survives.

The nest defence of honey bees is famous for, you know, the bees will effectively, most of the time when they sting, they’ll kill themselves. That killing themselves is not an accident, it’s on purpose. The stinger of a honey bee, when they sting you, will get stuck in your skin. That ensures that the venom gland, which is associated to the stinger, remains behind and keeps pumping venom into you. And that, for us, and for potential predators, that will maximise the amount of pain we receive, and that will create an association of, OK, these insects, they mean trouble. I’m going to stay away from them. So by killing themselves, they’re potentially ensuring the survival of their colony and even of other related colonies that look the same. In most other species, this level of altruism or self-destruction is not possible, because when you kill yourself, you’re effectively ending your ability to contribute to pass your genes forward, which is one of the ways we see evolution and natural selection happening.

So that’s, this social organisation that is relatively unique, so it’s a very small amount of animal groups are capable of eusociality, as we call it, is part of what makes them so interesting for evolutionary biologists but also so successful at an ecological level. They dominate landscapes. You have, in the Amazon rainforest is a good example because the biomass, if you could weigh every ant in the Amazon, it would be heavier than every vertebrate combined. So if you put in a scale ants on one side, on the other side, you have mammals, birds, reptiles, the ants would be heavier. And that’s because they are so good at what they do because of the social organisation that they are able to completely dominate a landscape.

Associate Professor Adrian Paterson

They also seem to dominate the kind of market share of knowledge, if you like. And I’ve really seen that recently with my little tiny granddaughter who has a few noises for different animals now. She’s too young to have words. But she’s got meow for the cat and the usual. But she’s got a bzzz, mostly for bees, generally for insects. But she’s already learnt something about bees. I’m sure in your, what you do day to day, you have lots of people who will have an opinion about bees and wasps and other social insects like that. So what do you think the appeal is?

Dr Mateus Detoni

Oh, that’s another good question. Actually, it’s very much part of my life. I definitely noticed because I’ve been participating in research projects with social wasps since my first semester as an undergrad in university, so that’ll be 15 years ago. And I made the sidestep to studying honey bee biology, not until I started working with Manaaki Whenua. There’s definitely been a very good effort, media-wise and science-wise, to promote honey bees as the flagship pollinator conservation threat. We know that our insect diversity worldwide is on decline, and bees are usually the face of that campaign. When we’re talking about saving insects, people talk about saving the bees and specifically with honey bees in mind, which is a bit ironic considering that they’re mostly fine. Being the devil’s advocate, my supervisor would skin me alive for saying what I’m about to say, but when you look at a honey bee and you look at a wasp, honey bees are furry. They’re kind of soft looking and wasps are all angles and sharpness, so it kind of guides the public perception of them as well.

Associate Professor Adrian Paterson

Well, you look like you shouldn’t mess with a wasp, which is the whole message they’re sending, and so we don’t like messing with them.

Dr Mateus Detoni

Yeah, but I’ll say this. Having worked with honey bees specifically and social wasps of a lot of different species, both back home and here in New Zealand, I would definitely say that I’d rather work with wasps most of the time when it comes to my own safety. I find bees – well, first, the hives are massive. An average commercial beehive will have 40,000 bees. And unlike most wasps, bees usually have guards sitting at the entrance of the nest looking for trouble. Those five or 10 bees, they usually, if you’re around for too much, they start to think you’re trouble, and they start to dive bomb you and chase you around, and I find that quite unnerving. With wasps, usually the colony is either happy or unhappy. You can tell if you’ve worked with them long enough. If they’re unhappy, you put some distance. If you’re wearing a bee suit, you’ll be fine. So I find bees a little moodier, less predictable. I’ve got a colleague that says, and I fully agree with that statement, that, “I’ve earned every wasp sting I’ve had in my career, and I have not deserved any of the bee stings I’ve got.”

Tom Goulter

One of my useless takes is, I love all God’s creatures, but wasps – if we could get rid of them, I would do that. Am I wrong?

Dr Mateus Detoni

Yes.

Tom Goulter

Good, yeah. Explain to me this.

Dr Mateus Detoni

At multiple levels, yes. First, wasps are now, or rather Hymenoptera – the order of insects where we have wasps and bees and ants – is the most diverse animal group in the world as of somewhat recently. It used to be beetles, now it’s the Hymenopterans. And it’s not because of the social wasps, so I’m not defending my own corner. It’s because of the small parasitic wasps that are incredibly diverse, incredibly hard to identify, and they’re tiny a lot of the time.

Tom Goulter

So not my problem.

Dr Mateus Detoni

Yeah, but they certainly fill a very important part of the ecosystem. So with parasitic wasps, we use them a lot for biocontrol around the world. So in New Zealand, we are one of the world’s leading biocontrol research countries. And a lot of times when we have an invasive pest, you usually have one species of wasp that attacks that pest at a very specific species or genus level. And our ability to identify those parasitoids, as we call them, and rear them and use them as a tool to help control pests is amazing.

But not just that, and I know that, in New Zealand, we don’t have native social wasps. We only have the invasive ones, and that somewhat alleviates the fact that people really, really hate them here. But in their native range in Europe, in the Americas, in Africa and Asia, they are a very integral part of the ecosystem, in the same way that bees are – maybe not commercially, but they are very good at controlling agricultural pests. They play a role in pollination. They can play a role in seed dispersal. So where they’re supposed to be, maybe they’ll still be stinging people and people will still not like them very much. But they definitely play a huge role, especially because, like all other social insects, they operate at landscape level. And so you remove them from the equation, suddenly you might start to have problems in areas of ecology that you didn’t anticipate.

Associate Professor Adrian Paterson

The other issue with parasitoid wasps is just – and I see that Tom has got this great t-shirt from the Aliens movie – is the whole parasitoid part of the life cycle where they lay eggs and paralyse living things and then they hatch out like a chest burster.

Tom Goulter

Just like my beloved Alien.

Associate Professor Adrian Paterson

Exactly, and to most people, that does sound kind of slightly horrific, just thinking about lying there parasitised while these things are growing inside you to eat their way out. And I know that people over the decades and centuries have had real problems with this, about, “Well, what kind of world do we live in where this happens?” And yet we actually rely on this to actually help us a lot, this way of life.

Dr Mateus Detoni

I think – I’m not going to quote verbatim, but I think there’s a quote by Charles Darwin, where he says something along the lines of “I cannot believe in a benevolent deity who created parasitic wasps”.

Tom Goulter

Right on.

Associate Professor Adrian Paterson

Yeah, yeah.

Dr Mateus Detoni

So it is quite horrific. So these parasitoids, they will usually lay eggs on living insects, and the eggs will – sometimes they will anaesthetise the insect first. Sometimes they’ll just lay the eggs on a caterpillar or something like that. And the eggs will hatch, either on or in the host. And the wasp larva will typically eat them alive, starting from the non-vital organs, so they can feed as long as possible.

Associate Professor Adrian Paterson

Keep it alive just to –

Dr Mateus Detoni

Yeah.

Associate Professor Adrian Paterson

I think that’s the insidious bit that gets people.

Dr Mateus Detoni

Yeah, and eventually they’ll finish their meal, and they’ll become pupa, and they’ll become an adult wasp and go mate and find their own host to lay eggs on. So it is quite horrific but also fascinating for an insect biologist, yeah.

Associate Professor Adrian Paterson

So you’ve mentioned the Amazon rainforest and your undergraduate just a little bit. So that was in Brazil.

Dr Mateus Detoni

Correct, I am Brazilian.

Associate Professor Adrian Paterson

Yeah, you’re Brazilian, and you ended up in University of Otago down in Dunedin for quite some time and now you’re in Lincoln. And so what brings a Brazilian lad all the way around the world to study essentially social insects that don’t actually, well, officially live in this country other than as introduced species?

Dr Mateus Detoni

There’s two halves to that answer. The first one is, when I finished my master’s degree in Brazil, in my hometown, I wanted to have an overseas experience for my PhD. So I had that in mind. And at that time, the Brazilian Government was doing an exchange studies programme where, if a university accepted you as a student or a PhD student, they would fund 2 years of your studies plus stipend. All you had to do was to get a willing supervisor to say yes.

So I started kind of shopping around, I suppose. And I put together a list of people that I would like to work with based on literature. And I started from the top. I was like, “OK, I’m going to get my rejections from the top down.” And I emailed a very important researcher in the wasp biology field, Robert Jeanne. He is now retired. He was a professor at, I think, the University of Wisconsin. So I contacted him saying, “I’m a master’s student. I’ve been working with wasp behaviour. I’d like to do a PhD with you,” fully expecting him never to reply to a lowly Brazilian student he’s never heard about. And to my surprise, he replied one day later. Very generous message saying that, “I would love to take you as a student, but I’m, as of last Friday, retired. Here’s a list of people I’ve worked with or former students that are looking for postgrad students for themselves, and here’s their interests and how they align with what you told me.” Which it was so generous and so sweet.

And then I had this list in hand, and the first name that I contacted from that list was Jenny Jandt, who works at Otago, ended up being my supervisor. So what drew me to contact her was she was also focused very strongly in behaviour, and not using behaviour as kind of a side to her main interest, but it was her main interest is social insect behaviour, as it is mine. And the other thing is that she lived here in New Zealand. Now, I’ve always wanted to come to New Zealand. I know this is very much of a trope, but I’m, being a big nerd, I love Lord of the Rings, so I’ve always wanted to visit to see the landscape with my own eyes. So this was pretty much two birds with one stone, and then I came here.

The other reason why, despite the fact that we do not have native wasps in New Zealand, is because we experience what is probably the worst land ecosystem invasion of wasps in recorded history in New Zealand with the Vespula – yellow jackets, common wasps, whatever you want to call them. If you’re studying them, even if you’re not studying how to kill them or to control them, that means you get access to fantastic sample sizes that usually overseas you’d struggle with quite a bit, as I did in my master’s. So coming here was like, OK, the number of wasps I get is not going to be a problem. We can focus on the science of it. And that’s how I ended up here. And after I came and I studied in Dunedin for 4 years and worked for a bit over there, I fell in love with the country and decided to stay.

Tom Goulter

We don’t put that on tourist posters, but maybe we should. “More wasps than anywhere.”

Dr Mateus Detoni

It is true. So for the Vespula, just to make it very clear, we’re talking about the wasps that typically nest underground, and they’re the bright yellow ones that we have all around New Zealand. We’ve got a couple of species, the common wasp and the German wasp. Their record population is in their native range, so they’re native over, generally speaking, to Eurasia, so northern hemisphere, Palearctic Circle. A very high-density population over there would be 12 nests in a hectare. In New Zealand, we have recorded over 40. So that’s in a football field, you’d have 80 nests, top density. And those are usually found in very specific conditions, typically in beech forests at the height of summer. But it’s still, it’s very high populations we’re talking about. And it has catastrophic effects on ecology.

Associate Professor Adrian Paterson

So what are the really big downsides? Obviously you get stung, but for everything else, what are the downsides?

Dr Mateus Detoni

Well, the Vespula invasion of New Zealand’s become a textbook example around the world for what happens when an invasive social wasp population gets out of control. Unlike bees, social wasps are all 100% predators. They’re carnivores, right? So these wasps, they’ll typically, in terms of food, they will look for two different kinds of things. They will look for prey, and the prey is used to feed their young. So they need that protein from usually other insect species to grow and develop into adult wasps. But they’ll also look for sugary food to feed the adults themselves. So the adults cannot actually ingest solids very well because they have a very narrow waist. So they just use the sugary food to keep them going – energy.

Associate Professor Adrian Paterson

So is this why when you’re drinking a beer in a can and the wasp would come and often go into the can or into the bottle.

Dr Mateus Detoni

Exactly. Vespula, they really like fermented sugars, so the smell of fermented beer makes them very happy.

Associate Professor Adrian Paterson

So it’s not just that it’s sugary, it’s that it’s fermented sugar.

Dr Mateus Detoni

Yeah.

Associate Professor Adrian Paterson

Wow, OK.

Dr Mateus Detoni

They’ll go for fresh nectar, flower nectar. They’ll go for juice, but beer, and in my experience, Speights is probably the best we have to attract them. So it’s those two things that they look for. So when they invaded New Zealand, they did well mostly everywhere where they got to. So Vespula germanica, the German wasp, arrived just after World War II. First in Hamilton is where they were first spotted. Vulgaris, it arrived, I think in the 70s. I believe it was around Dunedin or maybe in the North Island. I can’t remember right now. But both of them did quite well everywhere because we don’t have native social wasps. We don’t have, as a result, predators or enemies of native social wasps. So there was nothing to compete with them. There was nothing to attack them. They did very very well because, again, these are very successful, adaptable predators.

The problem, and the reason why they became such a flagship for social wasp invasions, is when they got to the beech forest system. So the beech forests of New Zealand, we have a native species of insect that lives in the beech trees or on the beech trees. They feed on the sap, and they’ll produce the honeydew. If you’ve been to a beech forest, you know exactly what I’m talking about. So the honeydew that the scale insects produce is one of the bases of those ecosystems. So the birds will feed on that. Other insects might feed on that. Fungi might grow from drops of honeydew falling to the floor. So it fuels the whole beech forest ecosystem.

When the wasps arrive, they completely monopolise that system because they’re very efficient, they can get very numerous, and they can be quite aggressive in foraging. So they pretty much outcompete most other species. At the same time they are getting all the honeydew, they also need the protein, so they’ll hunt down local invertebrates, local insects. Then they’re depleting the local fauna. And there’s even some harrowing accounts have been published about wasps pestering bird nests so much the chicks would drop, and because they can scavenge, they would eat the chicks.

I think one of the saddest quotes I have, it’s a book, The Vulgar Wasp, written by Phil Lester from Victoria University of Wellington, and I think he puts a quote in there from someone who’s worked around the Nelson Lakes area, which is where the worst of the invasion historically has been, saying that, when they grew up in that area, they would go for a stroll in the bush and hear all the birdsong. Nowadays, you go in summer, all you hear is the buzz of wasps. And I find that particularly very sad. It’s a failure of our conservation efforts or biosecurity efforts.

And of course, I’m not pointing fingers at all. They’re very hard to contain, very hard to predict, and people have been working very hard to get rid of them. So they’ve been here for a long time. They’re not recent arrivals. We do have some recent arrivals in paper wasps. So paper wasps, we have a few that pre-date Vespula, and those are usually, most of them are found more commonly in the North Island rather than down here in the South Island, although they are becoming more common here.

Associate Professor Adrian Paterson

I just saw a paper wasp setting up a nest near Arrowtown about 2 weeks ago.

Dr Mateus Detoni

Oh, wow.

Associate Professor Adrian Paterson

On the outside of the building.

Dr Mateus Detoni

Arrowtown? So that’ll be near Queenstown.

Associate Professor Adrian Paterson

Yeah.

Dr Mateus Detoni

Oh, wow. That’s quite far south. Because yeah. And that’s probably, if I had to guess, they’ll probably be the European paper wasp, Polistes dominula, which I have just found also for the first time in Ashburton where I live. So there was, at least in iNaturalist, there were no records of them being there. They’re definitely spreading south. But we have one Australian or Tasmanian species of paper wasp that has been, I think, here for over 100 years now. And we have one Asian species of paper wasp and one European species of paper wasp. The European one, Polistes dominula, has arrived probably between 2013 and 16, so it’s quite recent, and that’s the one that’s spreading slowly over the South Island.

Tom Goulter

But that’s not the hottest ticket in terms of insect invasions. Now we’re contending with the yellow-legged hornet. Is that right?

Dr Mateus Detoni

Ah, yes. So that’s, yeah, it’s been all the buzz.

Associate Professor Adrian Paterson

Oh, good one.

Dr Mateus Detoni

Excuse the pun. So just to make it clear, I think there’s a lot of confusion about wasp, hornet. Every hornet is a wasp. In fact, every hornet is a social wasp, at least as far as common names go. Not every wasp is a hornet. So hornets are usually, it’s a common name that people usually use to describe a couple of different genera of social wasps, and they tend to be very big and bulky. Vespa is one of these genuses – it’s the one that Vespa velutina, the yellow-legged hornet, belongs to – and Dolichovespula is the other one. It’s common in North America. And it’s also, interestingly enough, we did have an incursion of the bald-faced hornet, which is the Dolichovespula, but they never managed to establish.

So yeah, the yellow-legged hornet is an Asian species of hornet, of social wasp. They are a known invader, so they’ve invaded Europe as well in what we assume is the standard route for wasp invasions. It’s a wintering queen – so over winter, the queen’s usually the only insect that survives the death of the colony. They will hide somewhere nice and warm to spend the winter in safety, and they will emerge in spring to start their own colony from scratch. Sometimes the place they choose to spend winter over is an old piano, someone’s wardrobe, and those things can be moved around the world, and then that’s how you end up accidentally having a wasp invasion. So this is the hypothesised way that these invasions happen. So they’ve reached France, I believe, in the early 2000s, and they’ve spread across Europe where they’re a big problem.

The reason why having the yellow-legged hornet in New Zealand is a little more concerning than the arrival of other groups or other species of social wasp, which would be fairly concerning on their own, is because the yellow-legged hornet, like some other species of hornet, specialise somewhat in attacking other social insects. So they like eating other social insects. They’re very good at invading colonies or hives, taking down the guards, and eating adults, eating larva, eating honey if it’s talking about honey bees. In Europe, this species of hornet has been known to have a third of their diet be comprised of honey bees, which is something that our Vespulas don’t do. They might attack beehives. They can definitely cause beehive collapse, but it would be very unusual for the common wasp or the German wasp to invade and raid a honey bee hive in that scale. The hornets are able to do that. They are very large. They’re very hardy, and they’re able to kill many bees, each individual I mean.

So that has made people very scared because it’s clearly, as with any other wasp invader, it’s a conservation issue and a public health issue. But now we’re also talking about something that might endanger food production in a very significant way, potentially, right. So yeah, people have been quite worried about that with good reason. And in fact, I was – last year when the invasion was first reported, I was teaching in central China, where the species is native to, and then I got to see some of them around during summer. And then I just heard, right after taking some pictures, I heard that they’d made their way to New Zealand. It was quite shocking.

Tom Goulter

What are we worried about happening from the hornets?

Dr Mateus Detoni

Well, the worst thing that can happen is them becoming effectively established. So far, we cannot say they’re established in New Zealand. We just found our first – our first reports were just made. These are insects that live in yearly cycles, so they will be alive from late spring, mid to late spring, all the way up to the beginning of winter or late autumn. As far as we know, this is the first year they’ve been active. Most likely, based on the numbers we’re seeing, they were here last summer. Maybe just one or a couple of founding queens, and they are the ones who originated this new population we’re seeing this year.

The worst thing that can happen is for us not to be able to contain them. As long as they’re contained, as long as they’re potentially eradicated. Typically, when we’re talking about invasive species, eradication is a bit of a taboo word. It’s very hard to achieve. You need a lot of effort, a lot of technology. So once a species is established, it’s very difficult to get rid of them, at least when we’re talking about New Zealand as a whole country, it’s a very, very difficult goal. But for the hornet, this is probably the only time that we’ll have a chance to eradicate them is right now when the invasion is localised, ideally contained. So if we manage to kill all of them or most of them, and over the next 2 to 3 years, the numbers go down consistently or cease, we will probably avoid a very major source of economical and ecological damage to our country. If we don’t, if they start to spread, then on one hand, we might not have to worry about Vespula as much because they most likely will attack Vespula as well, but we’ll have a bigger, potentially more commercially damaging wasp to deal with.

Associate Professor Adrian Paterson

So Mateus, you’re also interested in the South Pacific, wasp invasions there. So are they typically having the same issues with the same species, or because it’s hotter, there are different species or ...?

Dr Mateus Detoni

Yeah, so they are – actually, I’m very interested in that. I’m wrapping up a project on that. Surprisingly, there is not a centralised source of knowledge on the invasive wasps for our corner of the world. There’s a lot of studies in New Zealand, there’s a lot of studies in Australia, which share a lot of same invading species, the common and German wasp. But when you look at the other South Pacific nations, that information is not readily available. So this is something that I’ve been trying to address and pretty much looking at historical records of, first, what social wasps are around here? If they’re invasive, when did they arrive? What do we know about this invasion? Where do they come from? When did they arrive? Where do they come from? How do they affect local ecology, local biology? And we don’t know much. There’s a lack of studies, which I think is pretty unfortunately quite common to the South Pacific.

Associate Professor Adrian Paterson

Can we compare it to, I don’t know, the Caribbean or other islands areas that are similarly hot or ...?

Dr Mateus Detoni

So that’s the interesting part. The South Pacific is quite unique because social wasps are native mostly everywhere in the world. Here we have kind of a black box of diversity, despite the fact that we’re right next to Southeast Asia, which is considered a) a hotspot of wasp biodiversity but b) also probably where they first originated in. So that probably has to do with the fact that we’re mostly volcanic islands that appeared after wasps first evolved, and maybe they couldn’t before humans spread or at least not spread as well as they –

Associate Professor Adrian Paterson

Not many pianos and things –

Dr Mateus Detoni

Yeah, correct.

Associate Professor Adrian Paterson

... wardrobes moving around the world 2 million years ago.

Dr Mateus Detoni

Yeah, but because of that, we’re particularly at risk from these invasions because we don’t have biodiversity that has evolved to contend with these wasps being around. So the Pacific does have native social wasps or at least self-introduced a long time ago. So we can’t really compare. That was one of the challenges in doing that project, and when you get to, OK, let’s compare, where else can we look at that has a similar biogeography dynamic? And the answer is nowhere really, because everywhere else where we have an island system, typically, they’ll have species that are considered native or at least self-introduced.

Associate Professor Adrian Paterson

Been there a long time, yep.

Dr Mateus Detoni

Yeah, so the South Pacific is quite unique in that regard. To answer your first question, our island neighbours, their fauna is typically quite different from ours. It’s way more common to find paper wasps in those islands. Paper wasps tend to be more diverse in the tropical areas of the world, the group of the paper wasps. They also don’t deal with cold very well, so that’s maybe one reason why the ground-nesting wasps tend to do better in New Zealand.

Especially we have one species of paper wasp that is widespread across the Pacific, which is called Polistes olivaceus. It’s a very large yellow paper wasp, so if you’ve been to, let’s say, Niue around summertime, you’ll see them everywhere. It will be very similar to going to a beech forest in New Zealand and seeing Vespula everywhere. And they’re considerably larger. So when you look at a map of these invaders of the Pacific, you can almost trace what I imagine would be the route of an East India company ship going from Singapore all the way to French Polynesia or something like that. So you can probably see where these wasps were getting off the ship and establishing across the islands.

Associate Professor Adrian Paterson

So you’ve talked a bit about the dangers of working with these insects, but maybe tell us a little more. If you’re going out there, I mean, I’ve seen some of the videos of your research and so on, and you’re often trying to antagonise the actual wasps to do stuff so that they’ll come out and interact. So talk us through, what sort of gear do you need to work in those kind of frontline kind of research?

Dr Mateus Detoni

Yeah, I think, I’m particularly unusual even amongst wasp researchers because I think most people who do work with wasps, they are doing their best to not get stung or not rile them up. I did my PhD research on wasp aggressiveness in the context of nest defence. So I was trying to get them to be angry on purpose and see what aspects of their biology or their ecology or their genetics can help us understand why are some nests very aggressive and others are not. Because that is something we do have even in New Zealand. We have specific colonies which are very aggressive and specific colonies who are not. So trying to understand where that variation comes from and what does that mean to their evolution, to their biology, was the major goal of my thesis.

So a lot of the time I would go out to the field after finding the colonies. I would put on a bee suit. You have to be very careful by taping yourself around where the gloves meet the suit, where the gumboots meet the suit, because they are pretty good at getting in nooks and crannies. And then I would do my behavioural trials, which when I was trying to quantify the aggressiveness of a specific colony, I would simulate a predator mammal attack. So in their native range, these insects are preyed on by bears, by badgers, by large carnivores, essentially. The one thing that these animals do when they’re going for a wasp nest is that they’ll dig around the nest and they’ll put their big snouts in there sniffing because they want to eat the larva – the larva are the juicy protein treat that they get.

The way I simulated that was by using a plastic tube that went from inside my bee suit, connected to my mouth, into the wasp nest, and I would puff air inside of it. That mammal breath is a very easy way to get them to think there’s a predator around, and they would come out not very happy with me. And then I’d have – I had a whole set-up with a target that could capture their attention, and every time they struck the target, it picked up the individual sounds of the stings, and I could use the sound file to analyse how many times did this colony strike my target. And that’s the way we found to measure aggressiveness.

Tom Goulter

So do you have a favourite kind of wasp to be stung by?

Dr Mateus Detoni

Vespula is not bad. I don’t know if you guys know Justin Schmidt. He was a social insect researcher, and he came up with the Schmidt pain index. So he made it his life’s mission to get stung by every stinging insect there is and rank them according to how much it hurts, which earned him an Ig Nobel Prize. But he was a treasured member of the social insect community. And honey bees and Vespula are ranked the lowest of the low when it comes to pain. I think he compares it to being poked with a hot needle, and I agree with that. So as long as it’s not in a joint area, because then you might get some swelling and makes it annoying to work, it’s fine. It’s not the end of the world. The bigger wasps tend to have longer, bigger stingers and the ability to maybe deliver more venom. So big paper wasps or hornets. Never been stung by a hornet before, but definitely have been stung by paper wasps, over jackets and things like that, and it’s not very much fun.

Associate Professor Adrian Paterson

And so the murder hornets that you always hear about, where are they ranking? Are they in that same –

Dr Mateus Detoni

I think quite high. So people call the murder hornet is called a Vespa mandarinia, so it’s a related species to the yellow-legged hornet. They are the largest species of social wasp in the world. They may be the largest species of social insect maybe. So they’re very, very big. They’re about an inch long, each worker, and the queens I think get a little bigger. Another species that really likes attacking other social insects. And they are – if enough of them sting a person, they are able to sometimes cause death, not from allergy, just from overexposure to venom. But yeah, so they are feared in their native range for a good reason. They are big and scary looking.

Associate Professor Adrian Paterson

So when you get a postgraduate student who might be interested in signing up for a master’s or a PhD, do you give them a pain test or anything?

Dr Mateus Detoni

That’s always the first thing I ask. If there’s a student that wants to work with me and they want to work with wasps, I just say, “Are you squeamish around insects? Are you scared of being stung?” It definitely takes some nerve to be – sometimes it feels like you’re swimming with sharks when you’re wearing the bee suit, and there’s 20, 30 wasps trying to get to you through the veil in front of your eyes. So it’s very unnerving. It’s not a very nice experience.

Tom Goulter

Chemically speaking, how does the venom of wasps work?

Dr Mateus Detoni

Good question. I am not a chemical biologist or biochemist, but my understanding is that it’s got neuroactive components. The venom of social wasps, and the venom of social insects in general, it’s not used for hunting. That is, solitary wasps might use venom to hunt and paralyse prey. These insects, they develop the venom for one reason, which is to protect themselves against predators. So it’s concocted to cause as much pain as possible, which then –

Associate Professor Adrian Paterson

And is that specifically for mammal predators, or are there bird predators?

Dr Mateus Detoni

Yeah, there are. It’s mostly mammals. It’s mostly mammals. Because one of the work I’ve done during my PhD was to find out who are the predators of social wasp colonies around the world for every social wasp there is. And overwhelmingly, it is mammals for these ground-nesting wasps. For paper wasps, you do have some occasional perching birds or birds of prey that might attack a nest if the nest is small enough and young enough. But usually a fully grown mature nest will be too dangerous for a bird to approach.

Tom Goulter

We have a question that we like to ask every guest on this podcast, which is, Mateus, what’s the last thing that made you curious?

Dr Mateus Detoni

Yesterday, I was watching a new show, I don’t know if you guys heard of it, called Pluribus by Vince Gilligan. It’s a sci-fi show, Pluribus. It’s a very mild spoiler of the first maybe 20 minutes of the first episode.

Tom Goulter

That’s OK.

Dr Mateus Detoni

OK, so in that show, it starts with those astrophysics researchers in the US that are waiting for extraterrestrial messages. And they –

Associate Professor Adrian Paterson

SETI or whatever?

Dr Mateus Detoni

Yeah, so they finally get a message from outer space, and they’re trying to understand is this an accidental noise or is this an actual message? And they figure out it is an extraterrestrial message sent to Earth. And at first they think it’s encoded, but it’s encoded in base four, like a quaternary instead of binary, like the language we use for computers. And then they keep like, “It doesn’t make sense. Why would you make a quaternary code? It’s so complicated.” And then one of them has the brilliant idea, well, it’s not a code. It’s not a message. The four bases, this is the code for RNA or DNA. So they put together a team of scientists very excitedly and synthesise RNA from the code that got sent by ETs. Now, what got me curious is, first, I really enjoyed the premise as a scientist, but also, would we do it in real life if we got an alien extraterrestrial message with a random DNA code? What would be the process?

Associate Professor Adrian Paterson

Again, what could go wrong?

Dr Mateus Detoni

Yeah, right. Because it’s very irresponsible, right? And if you watch the show, it proves to be quite an irresponsible decision. Because I imagine, not being a geneticist myself, that you could try to predict to some degree what proteins are these, is this code going to code? What’s it going to be like? But I’m very curious about the biosecurity aspect of synthesising a new genetic code, not knowing what it’ll turn out to be, and that just got me thinking.

Associate Professor Adrian Paterson

It would be very, well, at a very high PC-rated lab. That’s for sure.

Dr Mateus Detoni

Yeah, yeah .

Associate Professor Adrian Paterson

I don’t know how viable that would be because you’d have to build all the structure around it and yeah. Anyway, but makes it an interesting idea.

Tom Goulter

And a great answer. Thanks very much for your time, Mateus.

Dr Mateus Detoni

Oh, thank you.

Associate Professor Adrian Paterson

Thanks, Mateus.

Dr Mateus Detoni

It’s a pleasure.

Acknowledgements

Tom Goulter

Associate Professor Adrian Paterson, Lincoln University

Dr Mateus Detoni, Lincoln University

Kia Pākiki Canterbury logo, © Plains Media/Royal Society Te Apārangi (Canterbury Branch)

Images of Tom Goulter, Adrian Paterson and Mateus Detoni, © Royal Society Te Apārangi (Canterbury Branch)

Ngaro huruhuru – native bee (Leioproctus fulvescens), Steve Kerr, CC BY-SA 4.0

Parasitoid wasp (Pteromalus puparum), German wasp (Vespula germanica) and common wasp (Vespula vulgaris), Gail Hampshire, CC BY 2.0

European paper wasp (Polistes dominula), Judy Gallagher, CC BY 2.0

Yellow paper wasp (Polistes olivaceus), Charles J. Sharp, CC BY-SA 4.0

Asian giant hornet (Vespa mandarinia), Ken Ishigaki, CC BY 2.0