Training Dogs To Stop The Spread Of Spotted Lanternflies

RACHEL FELTMAN: This is Science Friday. I’m Rachel Feltman, sitting in for Ira Flatow. A bit later in the hour, we’ll take a look at how shifting seasons can change our behavior. Plus, with help from the James Webb Space Telescope, scientists may have identified six new rogue worlds.

But first, spotted lanternflies are an invasive pest here in the US. The adults are about an inch long. They’ve got striking red and black markings and, of course, spots. You’ve almost certainly seen them, or at least seen someone trying to stomp on one. Maybe you’ve even done some invasive pest control of your own.

We’ve gotten the green light to attack these invasive insects because of their worrisome tendency to chow down on certain crops, particularly fruit trees. But even the most enthusiastic bug smasher is no match for this invasion, so scientists are trying out a new method for identifying and getting rid of these insects– training dogs to sniff them out.

Joining me to talk about this strategy are my guests, Dr. Nathan Hall, director of the Canine Olfaction Research and Education Laboratory at Texas Tech, and Dr. Erica Feuerbacher, associate professor of applied animal welfare and behavior at Virginia Tech. Welcome, both of you, to Science Friday.

NATHAN HALL: Thank you so much for having me.

ERICA FEUERBACHER: Thanks for having us.

RACHEL FELTMAN: Nathan, I think most of us have seen drug-sniffing dogs in the airport. Is this project working with the same idea that you can train dogs to sniff out a particular object– in this case, a spotted lanternfly?

NATHAN HALL: Yeah, so for a long time, we’ve known that dogs have this great sense of smell, and we’ve been using it mostly in terms of detection of explosives and narcotics. But, recently, over the last, like, 15 to 20 years, that range has opened up a lot for a lot of conservation applications for trying to find species that are hard to detect or hard to find. USDA has been using them to find potential invasive things that might be coming in through airports. And now we’re really looking at this from potential agricultural needs and agricultural services.

RACHEL FELTMAN: So what stage of insect development are the dogs trained to find? I can’t help but picture them sort of leaping after the very spry adult bugs, which I assume is not what’s happening.

NATHAN HALL: Yeah, so right now we’ve been training the dogs to find these egg masses, which are these kind of brown, gloopy, I guess, egg masses that you could probably recognize on trees. But they also like to lay these on things like wood pellets or other things that you might pick up and transport to some location without even knowing that they’re there. So instead of trying to find that hoppy bug that you can easily see, we’ve been focused on those more hidden kind of egg masses that you wouldn’t otherwise see but might accidentally transport because you didn’t know they were there.

RACHEL FELTMAN: And Erica, how do you actually go about training a dog to sniff out a lanternfly?

ERICA FEUERBACHER: Yeah, so sniffing things is certainly a natural behavior for dogs. What we really have to train them to do is to communicate to us when they found their target odor. And we do that by teaching them that when they smell a certain odor– in this case, the egg masses of spotted lanternflies– that if they communicate to us, for example, sitting or staring or barking at us, that they’ll get something that’s highly valuable to them, either food or toys, usually. So by making that odor valuable to them, they’ll tell us where it is so they can get their preferred item.

RACHEL FELTMAN: And how many dogs have actually managed to develop a nose for lanternflies?

ERICA FEUERBACHER: So we’ve had a really great recruitment effort. When we went into this grant, we proposed kind of recruiting 120 teams or so. We had over 1,000 people register, indicating their interest in our project. We unfortunately couldn’t support that many teams. My graduate student, Sally Dickinson, does all the wrangling, so she has about 180 teams that she’s recruited and is working with. But about 60% to 70% of the dogs that are participating and their handlers have passed our very specific tests that they have to do, which are quite challenging. And 60% to 70% of those dogs have been passing that, indicating that they can detect spotted lanternfly egg masses, both in a very controlled setting, but also out in really applied settings, out where it’s busy and lots of other smells.

RACHEL FELTMAN: And what does that test actually look like?

ERICA FEUERBACHER: So they have three levels of testing that they go through. The first one is called the odor recognition test. And if anybody does competitive scent work with their dogs, we’ve adapted those tests to our test because those are a lot of the dogs that we have recruited. So that first test, they have a set of boxes out, many of which have distractor odors in them, like latex gloves or the mesh that we encapsulate the egg masses in. And only one or none of those boxes have spotted lanternfly egg masses. The dogs have 10 trials and they have to pass 80% of those. So they have to correctly identify where the odor is or that there is no odor on 8 out of 10 of those trials.

If they succeed on that, then they can go to our field evaluation test, where they are given– it’s outdoors, kind of in a lumberyard, like think of behind Lowe’s. And we put out three to five odor spaces for them with lots of distractors because it’s a natural environment. They have 5 minutes there and, again, have to correctly identify 80% on that test.

If they succeed on that, then they can go to our deployment test. And that’s really interesting. Dr. Hall mentioned that they’re being trained on egg masses, and we are using killed egg masses because we, of course, don’t want to contribute to any spread. The question is, can they transfer from the killed egg masses to live egg masses? And so, in our deployment test, we’re assessing that, and they absolutely can. The dogs are doing really phenomenally there and have even identified egg masses that we didn’t know were there. They’ll hit on something. The humans have to dig around, and sure enough, there’s an egg mass there.

RACHEL FELTMAN: Very cool. So once a dog sniffs out these live lanternfly eggs, what happens next? Is the idea that these egg masses get destroyed?

ERICA FEUERBACHER: Exactly. So what we’re hoping is that these dogs could be used to detect things that are being transported across the United States and prevent the increasing encroachment of these insects across the US. So the dogs could be deployed to go out and look at lumber yards or shipments.

RACHEL FELTMAN: And, Nathan, another question for you– what makes dog noses particularly good for this job?

NATHAN HALL: Well, dogs are quite interesting in that, one, they have great noses in comparison to a lot of animals. But, also, they sort of have a similar sense of smell to other animals, but they’re also just with us all the time. They make them super trainable. There have been studies that have been done with rats or particularly large pouched rats, and they have phenomenal detection capabilities. But you’re not going to be bringing those around to your lumber yard or to a variety of different checkpoints. So their bond with us, their availability, and their unique capabilities in terms of how they sniff.

There’s a couple of things that they do that is quite unique in comparison to how we scent around the world. One is sniffing. When you think about I’m going to take in a smell, like McDonald’s or a bakery, probably, whatever scent that you get, you take in this big inhale versus a dog is going to be sniffing at about 5 to 7 hertz. So that’s breathing in and out five to seven times within a second. And that causes unique airflow patterns that you don’t get when you’re just doing one continuous inhale. And then, also, just the way that the structure is of the dog’s nose, they have a bigger sort of surface area of these olfactory receptors inside of their nose than we do.

RACHEL FELTMAN: Yeah, I’m picturing having drug sniffing rats at the airport. And it’s just a very different vibe, though, in New York, we already have so many rats. I don’t know.

NATHAN HALL: Well, maybe that might be a great community science project to leverage all of the rats.

RACHEL FELTMAN: Totally, yeah. Everybody wins. Well, and part of what makes spotted lanternfly is such a big problem is that they spread so fast. A decade ago, we didn’t even have these insects in the US. And now we’ve got them in at least 16 states. So do you think this dog detection project can scale up enough to really slow the lanternflies down?

NATHAN HALL: Well, I think, you know, there are two things. One is the spotted lanternfly you can also think of as a model for potential future situations, where if we’re developing this capacity and this capability, then we’ll be so much more ready to deploy this in a future situation. But that’s not to say that the spotted lanternfly story is a done deal because where a lot of this spread is happening is going to be along human transport lines.

But that means that there’s a potential that if you had a detection technology to say, with relatively good accuracy in the lab, we were seeing 99% detection capabilities, 97% specificity. So if you had that capabilities, then you might at least be able to substantially reduce that spread that would then allow people– because when you have things going so fast, it’s hard to prepare. So if you can at least reduce that spread and put in place the things that might help prevent or at least tackle when they do come, you’d be in a much better prepared situation.

Right now, the comparison is human eyes, so getting a little mirror and sort of looking underneath the wood pallet and seeing if there’s something there. So that’s where dogs are particularly excelling is that potential capability to stop the spread or at least prevent some of that spread.

RACHEL FELTMAN: And Erica, I want to talk about the dogs in this study specifically. Are they finished with their duties after a certain period of time? Do they get to retire off on a sunny beach afterwards?

ERICA FEUERBACHER: So all of our dogs are owned dogs, and that’s what’s kind of unique about our project is that we are not selecting dogs that were purpose-bred or trained specifically for kind of a working career. These are dogs that people have as companions. We have a range of breeds from little tinies up to big ones, lots of mixed breeds. So it’s really fun that anybody with a dog can participate. And some of Nathan’s wonderful work has shown that, although I’m a German shepherd fan myself, that pugs in his experiments outperform shepherds. So really, any dog can do this.

But we see this project as a very cool way for their owners to partner with them. Their owners get to volunteer and contribute to their communities, and the dogs get a really fun enrichment activity. A lot of our participants want to keep doing more, and so that’s one of our goals in the future is how do we take these very motivated, very capable humans and dogs and make sure that they get to use their newly-found expertise going forward.

RACHEL FELTMAN: Awesome. Nathan, your lab is also exploring using dogs to detect other invasive species. Which ones are you most excited about?

NATHAN HALL: So we recently put out a paper on dogs’ detection of zebra mussel. There are these little larval stages of them that might come along and things like ballast water or other water samples that you wouldn’t be able to see that they’re in there. But it turns out the dogs are actually able to detect them. But what makes them particularly powerful is that they’re real-time. They can give you an answer right now. It takes our dogs about 300 milliseconds to sniff something and tell us if something is present or not, whereas other technologies require you to then go filter that and give you a 48-hour down-time processing. Think of it like your rapid versus your long-time COVID tests or PCR COVID tests.

RACHEL FELTMAN: That’s all the time we have for today. But I’d like to thank my guests, Dr. Nathan Hall, director of the Canine Olfaction Research and Education Laboratory at Texas Tech, and Dr. Erica Feuerbacher, associate professor of applied animal welfare and behavior at Virginia Tech. Thank you both so much for joining us.

NATHAN HALL: Thank you so much.

ERICA FEUERBACHER: Thanks for having us.

RACHEL FELTMAN: Listeners, if you want to read more about this project, you can head to our website, sciencefriday.com/sniff. That’s sciencefriday.com/sniff.

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