Who can take on the spruce budworm?

Joel Houle

Remember when you were a kid, playing outside, collecting bugs, putting them in a glass jar to see if they would fight each other? No? Was that just me? Anyway, on this episode, we’re going to look at a real-life bug battle that rivals Hulk Hogan vs. Andre the Giant at WrestleMania III! We have with us an entomologist — or bug expert — who’s going to break down this iconic matchup. Stay with us to find out which bug is brave enough to take on the spruce budworm…. Which one shall reign supreme?

Joel Houle

Welcome to a new episode of Simply Science — the podcast that talks about the amazing scientific work that our experts at Natural Resources Canada are doing. My name is Joel Houle. And joining me, as always, is my cohost Barb Ustina. Barb, how are you?

Barb Ustina

I’m feeling pretty good today! But I must admit, I’m feeling just a bit “punchy,” which isn’t surprising considering today we’re talking about bugs fighting bugs in nature.

Michelle Strong

Now that sounds familiar. Doesn’t it Greg?

Greg Rogers

It sure does!

Joel Houle

Is that Greg and Michelle from “Inspect and Protect”? This is a little unexpected, guys.

Greg Rogers

Hey Barb, hey Joel! It’s a bit of a coincidence — we’re also doing an episode on bugs fighting bugs! It’s an incredible story, actually: 100,000 wasps released into our forests to fight the emerald ash borer.

Michelle Strong

We’re even doing a wrestling theme as well!

Barb Ustina

Wow — on your podcast?? Hmm…. Isn’t that interesting?

Michelle Strong

Well, you know, it’s “Inspect and Protect” — the brand new podcast by the Canadian Food Inspection Agency! We take a deep dive into the latest projects in the world of plant health, animal health and food safety.

Greg Rogers

And we’re on Spotify, Apple Podcast, Google podcast, and pretty much any other app you like to podcast on.

Joel Houle

That was a well-done promo! Kudos! Well, seeing as we’re both doing similar topics and for some reason we’re kind of using the same wrestling theme — which, by the way, we totally did not steal from you guys — should we consider this a collaboration?

Michelle Strong

Good idea! Honestly, we would love that! By the way, we are so interested to know: Which bug is fighting the spruce budworm?

Barb Ustina

Wait… just hold on there just a second. We’re about to get to that, so stand by.

Greg Rogers

Okay, don’t mind us. We’ll just quietly lurk behind the scenes to hear the outcome.

Joel Houle

Sounds good. How about we touch base after the episode. Barb, what are we doing today?

Barb Ustina

Well, we’re doing something a little different today. You may notice a distinct wrestling theme to this episode. We have a hot matchup on our hands! Now, when I was a kid, I remember there was a show on TV called “Stampede Wrestling.” Every Saturday there were matches. We all knew it was set up, but that didn’t stop many people from tuning in. So that’s the extent of my wrestling knowledge. Joel, I hear you were a quite the fan back in the day.

Joel Houle

For sure! When I was a kid, I was a big fan of Macho Man Randy Savage and the Ultimate Warrior. I don’t watch it as much anymore, but when I do, it really brings out the kid in me. Maybe that’s why I’m so excited about this episode.

Barb Ustina

Should we bring out our guest?

Joel Houle

Wait! Before we do, can I say it? Can I say the line?

Barb Ustina

Don’t make me regret this. Sure, go ahead!

Joel Houle

I make no promises. Let’s get ready to rumble!!!!

Joel Houle

In order to break down this matchup for the ages — this “Contest in the Forest,” this “Melee against the Larvae,” if you will — we have with us entomologist Véronique Martel from the Laurentian Forestry Centre. Véronique, how are you?

Véronique Martel

I’m great, thank you. How about you?

Joel Houle

I’m great. Thank you for being with us here today. So before we start the analysis of the matchup, can you take a moment to tell us a little bit about yourself and what type of work that you do?

Véronique Martel

Yes. I am a research scientist in Quebec City with the Canadian Forest Service. So I do research on insects in forests and particularly insect feeding on other insects.

Barb Ustina

So, sort of like cannibalism and insects.

Véronique Martel

Well, we can talk about predation or parasitism.

Barb Ustina

Okay. Now I guess it’s time for us to introduce our opponents. First off, let’s talk about, and I’m going to use a bit of wrestling jargon here — correct me if I’m wrong, Joel, because you’re the pro at this. We’re going to start talking about the Heel, which is a wrestling term. That means the bad guy. Did I have that right?

Joel Houle

Well done, Barb. Well done.

Barb Ustina

Okay. And in this case, we’re going to talk about the spruce budworm. Can you tell us a little bit about the spruce budworm? And are we right in calling this insect the bad guy or the Heel?

Véronique Martel

Well, the spruce budworm is an insect. It’s native to North America, and it feeds on buds from balsam fir and spruce. So it’s a part of the natural ecosystem. So in that sense, we can actually say it’s a bad guy.

But the thing with spruce budworm is that it is out-breaking every 30 to 40 years. And when it does, the population gets so high that it actually kills trees. So in that sense, we could see it as a bad guy, but still kind of a natural bad guy.

Barb Ustina

How much damage does it cause?

Véronique Martel

Well, currently in the province of Quebec, it’s defoliating a little more than 13 millions of hectares to different degrees. Of course, all these trees won’t die, but some of the trees will die. So it has a huge impact over a pretty large scale and can, of course, affect the forest economy.

Joel Houle

So I guess in this situation, it’s not really that it’s a bad guy. It’s just that we need to control the numbers in order to save the trees. Correct?

Véronique Martel

Exactly. If we want to be able to use trees for our economy, then we’re kind of competing with it currently. So if we can control it somehow and reduce its impact, then it would help us.

Joel Houle

I see. So in order to control it, that’s where we have this match up here. So we’ve talked about the spruce budworm. For the purposes of this podcast, we’ll call it the Heel, the bad guy. So, who is our Baby Face, the good guy? Who is the challenger?

Véronique Martel

We would talk about a natural enemy — and that’s a pretty broad term — talking about any animals or organisms that would kill the spruce budworm to feed on it. But the spruce budworm is kind of particular in the way that there are more than a hundred different species attacking it. So a lot of parasitoids, which are insects laying their eggs inside the spruce budworm, they will eat it from the inside. Of course, this will kill it, and it’s going to attack eggs, larvae, or pupae depending on which parasitoid we’re talking about. So it’s a very diverse and abundant suit of natural enemies we’re talking about here.

Barb Ustina

So the insect, the parasitoid, will go into the spruce budworm egg and lay another egg inside that egg, and as that it grows, then it consumes the spruce budworm egg. Do I have that correct?

Véronique Martel

Some of them will affect the egg, some will attack the caterpillars, and some will attack the pupae. So it depends on which species of parasitoid that we’re talking about. But yes, you are correct. They’re laying their eggs inside the spruce budworm. And once they hatch, they feed on it, and eventually they will come out as an adult and go look for another spruce budworm to attack.

Joel Houle

That is one heck of a finishing move. So only one comes out at the end?

Véronique Martel

It’s either the spruce budworm or parasitoid. You could have more than one parasitoid coming out, but you cannot have a parasitoid and a surviving spruce budworm — it’s one or the other.

Barb Ustina

So this doesn’t sound like the typical one-on-one matchup where bugs are duking it out or anything like that. We’re talking about a Royal Rumble here. Joel, would you care to explain what a Royal Rumble is?

Joel Houle

Well, yes, as the expert here when it comes to wrestling. Now, a Royal Rumble is basically that you have, if I remember correctly, like 50 participants who all come in at the same time, and there’s an elimination process, and the last wrestler standing wins. So I guess in this situation that kind of fits, because you have everyone gaining up against the spruce budworm, I guess. So yeah, it’s kind of like a nature’s version of a Royal Rumble, I think.

Barb Ustina

Oh, yeah. It sounds like a very complex feud going on here that has occurred naturally in nature. But I’m wondering, how is NRCan involved in this research?

Véronique Martel

We’re studying that pretty closely, because it’s a natural way that nature controls spruce budworms. So that’s why it’s so interesting. We’re studying it to try to quantify its impacts and look at what’s going on. But also making sure that whenever we do something in the forest, is it a treatment that gets spruce budworm or cutting trees or whatever? We want to make sure that we’re not affecting these natural enemies too much because we want this battle to keep on going.

Barb Ustina

Now, how do you get the invading insect into the spruce budworm territory?

Véronique Martel

Well, they’re naturally present there. So they’re there; they’ve always been there. That’s why it’s kind of a natural balance occurring. So we don’t have to do anything.

But we could try to enhance their attacks by a different way. You would need a diverse forest. You we need some other trees in there — maybe deciduous or understory plants. This will all keep the parasitoids healthy and abundant. So that’s one of the things that we can do and we are doing. But you could also come in and try to release one of these insects to kind of boost its impact, like temporarily when you need it. So that’s something else we can do. And that’s called biological control.

Barb Ustina

How exactly do you do that?

Véronique Martel

What we’ve done as a research project is we focus on one species of parasitoid. It’s called trichogramma, and that one is attacking the egg of the spruce budworm. That’s a parasitoid that’s actually available commercially, you could just go online and buy it. So that’s pretty convenient. And then we release it at the same time when spruce budworm eggs are present. So we will increase the mortality of the spruce budworm by releasing it, by boosting its population. But that’s not going to last — it’s only going to last for the time that spruce budworm eggs are around. But then the population of the parasitoid will go down, and then it’s over. So it doesn’t stay like that.

Joel Houle

So there’s no lasting effect on the ecosystem. There’s no issues with balancing that ecosystem after the fact, right?

Véronique Martel

That’s correct. So we’re not affecting the balance in the long term. It’s really, really short-term. And the trichogramma, which are really, really small — we’re talking less than a millimetre long — they only survive a few days. So they will attack spruce budworm they find during those days. But then they’ll just die.

Barb Ustina

Now, would they attack any other insects? Or is there any other collateral damage by introducing these pests?

Véronique Martel

The species we’re using is attacking different lepidoptera eggs — the eggs from moths and butterfly. So yes, it can attack other things in the forest. But because we’re using it in places and at times when spruce budworm is abundant, the main eggs they’ll find are the ones from the spruce budworm. They’ll just kind of statistically encounter more spruce budworm. So they will mainly attack spruce budworm, but they might attack other species that are present if they are. But again, it’s a species that is naturally present in our forest. So it’s not like we’re bringing anything new in the system.

Joel Houle

So this trichogramma, right. Did I pronounce that correctly?

Véronique Martel

Yes.

Joel Houle

So it’s a type of wasp, right?

Véronique Martel

Exactly. It’s a wasp, but we call it a wasp because it’s related to wasps and bees and these kinds of insect. It’s not a wasp in the sense that it doesn’t sting humans or animals. It’s only going to lay its eggs inside lepidoptera eggs, so it’s a specialist in that sense. It doesn’t attack us like the wasps that we see. So they are wasps that are less than a millimetre long. You would probably wouldn’t even see them in the forest if you were around when we release them, and they wouldn’t be interested in you anyway. They’re really only interested in lepidoptera eggs.

Joel Houle

So how do you release these wasps? I’m just asking because, in my head, I kind of see you in the middle of the field with a jar, like “Fly free!” How does it work? How’s the process?

Véronique Martel

Well, you can do it like that. That would work, but it would probably not be really efficient. So the classical way with this is you can buy it like that. So you would always buy them — not as adults, the flying wasps — you would buy them when they’re still developing inside an egg. So you’re actually buying parasitoid eggs, and you release them right before they’ll come out of the egg. And classically, it would be glued on cardboard that you would hang on a branch.

So that’s pretty close to what you were just saying, me walking in the forest and, you know, I would just hang the cards on the branches, but that takes pretty long to do. So what we did in our research project is that we used drones to release them. Because it’s way more efficient. It’s fast. And, of course, it’s more expensive than me walking in the forest. But it’s the technology that’s more and more being used, so the price is also coming down with time.

Joel Houle

It’s probably way more fun, too, right?

Véronique Martel

Oh, absolutely.

Barb Ustina

Did they use helicopters at one point?

Véronique Martel

Yeah, exactly, they did that, they used helicopters like back in the eighties. So it’s pretty much the same thing as doing the drones. The idea is the same. But of course, the cost is not the same. And it’s more convenient too, of course, to have just a drone then a big helicopter. But it’s exactly the same thing.

Barb Ustina

And there are so many people who have drones, like at home these days. It seems everybody has a drone these days. So it’s conceivable that you could do this on your own property?

Véronique Martel

It is, although you would need some kind of a device to release it to kind of measure and make sure you’re releasing them. Different companies can do that kind of service. But in theory, anyone could do it if they have what’s needed. Although we always need to make sure that we’re following the regulations for using drones, because there are some rules to follow, of course, with that.

Joel Houle

So in what situation is it better to use these wasps, which I’ll say instead of trichogramma. What situation is it beneficial to use wasps versus the other different types of methods of controlling the spruce budworm?

Véronique Martel

It is still in developments, so we’re still trying. We know that it does work in the sense that we’re increasing the mortality of the spruce budworm eggs. So that’s the first step, of course.

But then we still need to refine a bit the details of how to make it the most efficient. But that’s not something that a province would use on a large scale. So I talked about more than 13 million hectares that are defoliated. You won’t use that; of course, that doesn’t make sense. But we could use it in places where we wouldn’t want to use insecticides. So it could be on private property where you have houses, protected areas or protected parts of pretty small-scale places where, for different reasons, insecticides are not the option that you would want. So that’s when it would be suitable.

Barb Ustina

Would this technique work to sort of control the population of any other pests or insects?

Véronique Martel

Well, we have several species of trichogramma that are found in different habitats, but they’re used against other species. They’re used, for example, in maze fields. They can be used in orchards. So, yes, these kind of insects, the trichogramma, can be used against different pest species. But you need to find the right trichogramma species to target the pest you’re trying to control. But that is absolutely something that is done. And it’s one of the most used species in biological control around the world.

Barb Ustina

Interesting. Wow!

Joel Houle

Okay. So if we look at this through the eyes of a matchup, is there a winner in this situation?

Véronique Martel

Yes and no. If you’re looking at one spruce budworm being attacked by one trichogramma, you would get a winner — it’s either a trichogramma or spruce budworm, so yes, you would have a winner. But if you look at the population scale, you don’t really have a winner because the trichogramma will never kill all the spruce budworms. So you will always have spruce budworm surviving, and you will always have trichogramma around. So naturally, there’s a balance. But if you look at a one-on-one battle, yes, you do have a winner every time.

Joel Houle

Very interesting! Véronique, are there any resources available for people who would like to know more about what we do for the spruce budworm? I know on Simply Science, we have a ton of videos, we have previous podcasts as well, for which we’ll share the links in the description of the podcast episode here. But are there any other resources that you’d like to guide people to online?

Véronique Martel

On Natural Resources Canada’s website, we have different publications on the spruce budworm, on the research that’s done. So, yes, there are several resources that people can look at from the Canadian Forest Service and Natural Resources Canada.

Joel Houle

Perfect. Thank you so much for taking the time to chat with us today and really for humoring us in this whole wrestling theme. We really appreciate it. So hopefully, we can have you back on the podcast sometime soon.

Véronique Martel

It’s always a pleasure. Thank you.

Barb Ustina

Thank you.

Joel Houle

It’s always great to talk to Véronique! She’s always so much fun!

Barb Ustina

I know! I’m always learning something new from her. Today, it’s all about the trichogramma, which I discovered isn’t really a “tricky grandma.” But if you paid careful attention during the podcast, you already know it’s a special insect that can throw a punch or two — figuratively, anyway.

Joel Houle

You know what we should do? We should do like the WWE and make some merch! I would totally wear a “Trichogramma 3:16” shirt!

Barb Ustina

Hmmm….  I’m not sure about that. Tell you what, why don’t you look into it. In the mean time, I’ll ask Greg and Michelle, what did you think the podcast?

Greg Rogers

It was really cool science! Thanks for having us on this episode! It was a real pleasure to listen in. 

Michelle Strong

You can catch the second episode of this bug fight collaboration on the CFIA’s official new podcast, “Inspect and Protect.” We’ll explore the fight between the invasive emerald ash borer, and 100,000 parasitic wasps. Bug you later!

Joel Houle

Between Michelle and Barb, the puns are flying left and right! Well, bye guys! Thank you so much for being here. So, if you, our audience, would like to learn more about how we fight the spruce budworm, check out links in the episode description. There is also a link to the Canadian Food Inspection Agency podcast “Inspect and Protect,” specifically their episode of “bugs fighting bugs.” It was great for us to do this collaboration with them! Make sure to check them out. You can also leave a review or share this episode. And if you share over X, make sure to tag us @NRCanScience. Or you can tweet at us directly. I’m at @JoelScience…

Barb Ustina

… and I’m @SimplyScienceB, that’s the letter B. I might remind everyone that Simply Science also has a website and a YouTube channel, which you should check out. We have in-depth articles of interest and videos that showcase the fascinating scientific work that we do at Natural Resources Canada. And you can find those links in the episode description as well. Social media channels too. And to steal another line from Michelle… Bug you later!

Joel Houle

Thanks Barb! And thank you so much, everyone for listening! We’ll see you at the next episode!

Barb Ustina

Bye!