The PrimateCast
The PrimateCast features conversations with renowned primatologists, wildlife scientists, conservationists and other professional animal enthusiasts about the processes and products of their work. The podcast is hosted and produced by Dr. Andrew MacIntosh, who's now the Senior Scientist, Wildlife Conservation at the Wilder Institute / Calgary Zoo. The show was incubated by Kyoto University's Center for International Collaboration and Advanced Studies in Primatology (CICASP), where Andrew worked from 2011-2024.
The PrimateCast
Nature's Apothecary: Monarchs, Milkweed, and the Art of Self-Medication with Dr. Jaap de Roode
Today's episode is all about royalty. No, not those odd primates shuffling around palaces in crowns and robes, but the monarchs of the butterfly world.
We're joined by Dr. Jaap de Roode, Samuel Candler Dobbs Professor of Biology at Emory University, who's one of the world's experts in insect self-medication.
Yup, you heard that right.
You might have caught one of our episodes (42, 60) with Mike Huffman, who discovered chimpanzees self-medicating in Tanzania to ward off parasites. Well, if you thought that was amazing (it is!), wait'll you hear Jaap talk about monarch butterflies!
After sharing his background in parasitology and population ecology, Jaap describes his work on medicative behaviors in monarch butterflies. From there, we go on to a whole bunch of other topics, like:
- how parasites affect monarch health, especially during their migrations
- the incredible diversity of animal medicative behaviors
- The role of citizen science in monarch conservation
- The importance of science communication in raising awareness
We also talk about Jaap's forthcoming book, Doctors by Nature: How Ants, Apes and Other Animals Heal Themselves, due out from Princeton University Press on March 4, 2025.
When we recorded the interview in spring 2023, Jaap was actually in Japan visiting Mike Huffman to talk about this book, so Mike joined us for the interview.
For anyone whose interested, I noticed that Jaap started a podcast of his own out of Emory University called Virulent Vortex. Check that out if you're interested in "infectious diseases across scales from molecules and pathogens to populations and pandemics, and everything in between" (from their website).
As always, I thoroughly enjoyed having this conversation, and learned a lot from Jaap about butterflies and beyond.
Disclaimer: The PrimateCast in no way, shape or form supports self-medicating with cigarette butts like those inventive urban birds in Mexico!
The PrimateCast is hosted and produced by Andrew MacIntosh. Artwork by Chris Martin. Music by Andre Goncalves.
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After the tune, a conversation with Dr Yap Darud of Emory University on the monarchs of the insect world and the meditative behaviors that help them fight disease. Conservation, behavior, primatology, typically primates, become the monkey.
Andrew MacIntosh:Hey everyone and welcome to the PrimateCast. I'm your host, andrew McIntosh, now of the Wilder Institute Calgary Zoo, and for this podcast, it's my job to chat with experts in primatology, wildlife science and beyond and share their stories with you. Today, we're definitely going beyond, as we'll be exploring the magical world of monarch butterflies and the behaviors that animals perform to keep themselves healthy. Yap DeRude is Samuel Candler Dobbs Professor of Biology at Emory University, and he's also the author of the forthcoming book Doctors by Nature how Ants, apes and Other Animals Heal Themselves, due out from Princeton University Press on March 4th.
Andrew MacIntosh:Now, in spring of 2023, while doing some research for his book, yap was in Japan visiting Mike Huffman, my close friend and mentor and one of the world's foremost experts in animal medicative behavior. The three of us took the opportunity to sit down together in the studio and record a wonderful conversation about monarch butterflies, the world of parasites and how their clash has led to one of the most astounding discoveries in animal science that these beautiful insects, and pretty much any other species that we've ever bothered to look at, are able to medicate to fight off infectious disease. Yap paints a vivid picture of this timeless struggle between host and any other species that we've ever bothered to look at are able to medicate to fight off infectious disease. Yap paints a vivid picture of this timeless struggle between host and parasite. He's a wonderful science communicator and has a knack for making tough ideas accessible while maintaining rigorous scientific rhetoric throughout. Now, since Mike made his discovery of self-medicating chimpanzees back in the late 1980s the field of animal self-medication.
Andrew MacIntosh:Self-medicating chimpanzees back in the late 1980s the field of animal self-medication, or just animal medication, since they can sometimes medicate not just themselves but others, as Yap likes to remind us. This field has exploded to include a dizzying array of species, and that's where Yap and his monarchs come in and why you'll want to stick around with us for this conversation. So let's get right into it. Here's my conversation, helped along by a healthy dose of sage wisdom and bad puns from Mike Huffman, with Dr Yap Darude. Yap Darude, thanks for joining the Primatecast, and let me start by asking you what you're doing here in Japan.
Jaap de Roode:I am here to visit Mike Huffman and to talk about all things animal self-medication. Mike and I have been corresponding for a while and a lot of my own work, which is on butterflies and medication, really is based on the groundbreaking studies that Mike did on chimpanzees back in the day, and currently I'm also writing a popular science book on the topic, and so really benefiting from my conversations with Mike, who's really the expert in the field.
Andrew MacIntosh:Cool. So we're definitely going to get to a lot of the self-medication in animals a bit later on. I want to maybe back up a little bit, if we can, and just maybe we can talk about how you got to where you are. So now you're at Emory University, mainly working with butterflies, and you have a greenhouse that you do a lot of cool experiments with, which we'll get to as well. But what was the kind of pathway for you to get here and get interested in self-medication? What is your background?
Jaap de Roode:So my background is really in parasitology. I was studying population biology in the Netherlands and from there deciding to do a PhD, choosing between a lot of different topics. I was at a conference about molecular ecology and there was one really inspiring talk on parasites and the professor was talking about competition between different strains of malaria parasites within the bloodstream of mice, and to me that was really interesting because I hadn't really thought about parasites sharing a host as an ecosystem where they compete. Like animals in the savannah compete for grass or trees, these parasites are competing for red blood cells. So I spoke to him and then started doing an internship in his lab for seven months and liked it so much that I then did a phd in his lab after that to really study these malaria parasites in mice.
Andrew MacIntosh:So around that time Mike and I maybe we can Mike can come in as well later but have been involved in groups in Japan working in malaria as well and malaria that can be shared, for example, between human and non-human primates. But at the time when you started I'm wondering how much consideration was given to the ecology of malaria parasitism. It seems like that obviously work comes out of kind of the medical field mainly, but your take, right from the beginning it sounds like, was more the ecology.
Jaap de Roode:Yeah, so ecology and evolution were really my background and so I really looked at the ecology within the host, right? So really seeing the host as an ecosystem in which you have competition for resources, in which you have shared enemies, which is the immune system, and so you can really think of this as different animals in a in a forest that compete for grass or trees and are attacked by predators, right and so, which is different from the kind of ecology when you think about malaria parasites that may jump from non-human species to humans, right, that's a completely different aspect of ecology, where you look at the ecosystem which have different hosts, where parasites jump between them, and that certainly was that's that's been a field I think that has grown a lot over the last few decades very interesting, but my interests originally were really about thinking about ecology within the host yeah, I remember in the must be I don't know if it was the late 1980s or 90s there was this movie that came out, starring dennis quaid and martin short, called uh, inner space, and that's right.
Andrew MacIntosh:I remember thinking, yeah, there's a lot of, there's a lot of ecolite. There was kind of a predator in there. It was like this kind of crazy guy in a suit that was trying to, you know, destroy their ship and right, but uh oh yeah, that was a great, great film. Yeah, it's a good fun, right? Yeah, but so you have these mice, uh, during your studies there, which are in a lab, so basically nobody would think about those laboratory mice as being in any kind of an interesting ecosystem setting but what's?
Andrew MacIntosh:happening within them. Um, is is obviously on different scales, but so what? What were the kind of, what were the kind of major insights that you found? And how did you kind of come to those thinking about mice as ecosystems?
Jaap de Roode:Yes, I was really interested in two major questions. One of them was to understand why parasites are virulent. So when we think about how we define, parasites are organisms that do damage, may cause disease or kill their hosts, but they don't give any benefits. But oftentimes people don't really ask why they do that, right? And when you ask that question, oftentimes the answer is well, give them enough time and they'll be benign, right. So oftentimes you may think of a parasite jumping between species that arrives in a new species and the kind of conventional wisdom is that because they depend on those hosts, they're going to be nice, they're not going to do damage or kill them.
Jaap de Roode:But from an evolutionary point of view that doesn't make any sense because everything is about fitness and for parasites that means getting as much transmission as you can. You know, go, you're in this host, you need to get to another host. How do you do that? How do you optimize that? In this host you need to get to another host. How do you do that? How do you optimize that?
Jaap de Roode:And so theory at the time was that virulence evolves. So the damage to the host evolves because it's an unavoidable product of maximizing the transmission between hosts and one of the factors that could drive that virulence higher is competition within hosts. So because then you have yet another thing to worry about. If you think from the perspective of a parasite, it's not just about how you maximize your transmission, but how do you maximize your transmission more than your competitors? And so then you get selection for faster growth rates, higher transmission, and therefore, because you grow faster, you produce more offspring, you kill more red blood cells, you do more damage, so you cause more disease. After you produce more offspring, you kill more red blood cells, you do more damage, so you cause more disease.
Jaap de Roode:So that was the theory that I was testing using the mice and the parasites, and that involved both mice and it involved mosquitoes as well. And then the other thing that I was interested in was drug resistance and really thinking about drug-resistant parasites. They first evolve through mutations, right, you get mutations. That gives drug resistance to this parasite, and then the question is what will happen? So it happens in a host, but then it's competing with parasites that are not resistant. So how does that competition shape that evolution and the spread of drug resistance? And then we found that the sensitive parasites can actually suppress the resistant parasites, so that competition can also in some ways be beneficial.
Andrew MacIntosh:Yeah, so can you. I mean just to maybe kind of break it down. It doesn't have to be in your system, in any kind of system.
Andrew MacIntosh:When we think about because that is a very common idea that parasites should evolve to become less fearful, to kind of support their existence and and and, in a way, evade the immune system, I suppose, um, but I think I've also uh, you know, this is kind of our field as well and come across various examples maybe of how it really depends on the system that you're looking at as well. Absolutely so do you have any good examples of, maybe for listeners, if you think about how transmission can drive parasites to be more virulent what might be an example of that.
Jaap de Roode:So I think some really obvious examples are parasites that need their hosts to die right To get transmission, and so there are a lot of parasites that have multiple host species within their life cycle.
Jaap de Roode:And so, for example, when you think about parasites that infect snails and the snails have to be eaten by birds so they can make it to the birds, and obviously making sure that snail gets eaten is is important for the parasite, but that means that snail is gone right. So I think that's a really good example you also think about maybe something closer to home for people is rabies virus. You think about rab. How does rabies spread from host to host? It is really through this kind of aggression where an infected individual starts biting another individual and in order to get that done, the parasite I refer to viruses as parasites as well is that that virus needs to infect the brain and really causing a lot of inflammation and a lot of disease. But really with the, you know the function of changing the behavior, so there's more regression, there's more production of saliva and therefore there's a higher chance of biting someone else and getting transmitted, and you know, but all of that causes so much damage that it also kills the host in the process.
Michael Huffman:What about the case of natural reservoirs? I'm thinking of Ebola, for example. It can run through a population of animals really quickly, or humans and decimate them, but it gets along quite well with the reservoir species or the carrier that's not affected. The reservoir species or the carrier that's not affected how does that deal with the idea that parasites should be compatible with their host and shouldn't be in the argument that you just gave?
Jaap de Roode:Yeah, I think it really depends on the exact combination of the host and the parasite how much virulence there is going to be, and so reservoir species often harbor parasites and viruses with a longer co-evolved relationship, and in some cases that can really lead to a more benign relationship. And then, yes, you often see that the species will jump, a virus or another parasite will jump to humans or another animal and cause a lot more damage, and so I think that's where that conventional wisdom came from. We should often see that, and you can even see it with the COVID-19 pandemic right, we have seen that the virus was a lot more virulent to start with, and it's become less virulent over time. At least you know, that's most of what the science says. Of course there's also more vaccination, which reduces the virulence too, but you often see that viruses or other parasites evolve less resistance. But it doesn't have to be that way. So it really depends on how the parasites maximize their transmission, and that can mean that they're going to be very non-virulent or they can be highly virulent.
Michael Huffman:Yeah. So in the case of Ebola, where is it happiest? In a host that it doesn't cause problems, or in humans or gorillas, where it runs through a population and it disappears?
Jaap de Roode:I would think it's probably happiest if viruses can be happy at all. You know I'd say it's happiest in a population where, where you may not even notice, it's there because it's it. If it, if it can infect more and more individuals in a population, it has a higher fitness and oftentimes what you see with viruses like ebola is that they burn themselves out right, they jump to humans and their mortality rates can be so high that they essentially kill before they can transmit.
Andrew MacIntosh:Yeah, I don't think we in the primate cast are going to get into the question of whether viruses will be happy or unhappy in their current situations. But you know, thinking about the ecosystems, you know we've also looked at through literature search in primates. You know, looked at through a literature search in primates.
Andrew MacIntosh:You know, as certain parasites have longer and longer kind of co-evolutionary histories with their hosts, those kind of specializations can also affect how the host will interact with other agents and parasitic organisms in the environment, and we've noticed that, according to the published literature, on a global scale, the primates that are more threatened tend to be those that have fewer parasites or less prevalent parasite infections. But it's different depending on whether you think of host specialists, parasites or generalists.
Andrew MacIntosh:And the scary thing there is that, you know, as host populations are in decline, maybe specialist parasite prevalence is on the decline as well, because they depend so much on those single hosts. It's really the generalists, you know, the ones that can hop from species to species, that may cause by far the most damage, and then that also would influence the virulence argument.
Jaap de Roode:Yeah, yeah. I also think the argument is somewhat driven by misunderstanding what parasites and viruses do in wild populations. It's not that long ago that people thought that malaria parasites or SIV viruses didn't cause any disease in the apes the wild apes, right and then humans get it and we get sick. But you know, when you actually study them, you find, yes, there are all sorts of disease symptoms.
Jaap de Roode:So I think that's another thing. So it's easy to say well, you know, they're just infecting those chimpanzees or gorillas and they're totally fine. And now we get them, we get sick. And I think that's just a misunderstanding. That hasn't been studied properly until recently.
Andrew MacIntosh:Yeah, super interesting the more we learn right about how some parasites have the capacity to modify the behavior of their hosts in a way that may lead to their destruction, to complete the life cycle of those parasites that have complex life cycles and involve multiple host species. And then this also kind of invokes the question of the general relationships that we see between parasites and their hosts. And I think this we can use this as a kind of segue into the self-medication, because you've written about self-medication as, or questioning self-medication as, parasite manipulation or host defense, and so maybe before we get into the host defense side of it, let's talk a little bit about parasite manipulation, and we can also use that to maybe transfer into butterflies. Yeah, so can you expand a little bit on what you've seen in your work and how certain parasites may be linked to manipulation of host behavior?
Jaap de Roode:Yeah, so maybe I can talk a little bit about how I got to butterflies Great and then start thinking about how I started approaching that. But I mentioned that I studied malaria parasites in mice and, as you pointed out, they were mice in the laboratory and you know. So you can think of it as an ecosystem within. But a mouse in a cage in a basement of a scientific building doesn't, you know, shout ecosystem or nature at you, right. So, and so I actually, throughout my PhD, I was kind of frustrated with the artificial nature of that research and I wanted to get to study a system that is a natural system.
Jaap de Roode:I also wanted to study a system that was a little bit simpler, that had a less complex life cycle. Malaria parasites have the mammal as a host and the mosquitoes, and they have to get through both of them, and I wanted to have a parasite that just has one host makes it makes it easier to study. I wanted to be able to study it in the wild as well as in the lab, and I found parasites of monarch butterflies. They're protozoan parasites, actually not that distantly related from malaria parasites and it. When I first learned about them, I was really wowed by it because I thought this is really exciting.
Jaap de Roode:These are parasites in in a butterfly species that I knew from a spectacular migration they undertake every year, but I had never heard of these parasites before and I thought, wow, this is a really good opportunity to start thinking about these parasites in a wild population yeah and um, and you know and it's interesting too because I started with the question of what makes parasites virulent so I took that question to the butterflies and so that's really the first project I did trying to understand if that selection for transmission can select for virulence and I found that with a lot of experiments I did trying to understand if that selection for transmission can select for virulence and I found that with a lot of experiments I did, and then the idea of behavior and medication really came later and that was really when I started thinking about the relationship between the host and the parasite and the host plants that the monarchs use, because monarchs are butterflies, so the adult butterflies can drink nectar from any flower.
Jaap de Roode:The caterpillars are specialized and they're specialized on milkweeds and from the literature we knew that the milkweeds have really exciting chemicals called cardenolides. They're toxins. If we have too many of them we die. In the right dose we can use them as heart medicine. But the monarch butterflies can deal with these toxins very easily and the literature also told us that the monarchs can use the toxins to protect themselves against predators and in fact they advertise their toxicity. So what they do is they feed on the milkweeds, take the toxins out of the milkweeds, put it in their own tissue and then advertise using their black and white and orange to predators that they're bad tasting I I wanted to ask you actually, um when?
Andrew MacIntosh:so the? That's a nice an example of apple semitism you have this warning coloration in the monarch butterflies and they are toxic to potential predators. But I was curious in the context of signaling that toxicity, do you notice whether the caterpillars that intake more or less of the toxin from the plant actually have variation in the colorations that they have? So is there a correlation between the degree of toxicity, for example, in the caterpillar, and then the coloration of the adult butterfly?
Jaap de Roode:there is some variation in the coloration, but as far as I know and as far as we have looked at it, there is very little effect of the particular toxicity levels driving that color variation.
Andrew MacIntosh:so I think it's, in some ways, the color variation is very much just those specific colors that tell predators to stay away, because normally when we think of, for example, signaling for reproductive purposes if you think of birds, there's this handicap principle, which has been challenged, but in any case the animals that are in worse physical condition don't seem to produce the same kind of strength of signal. So I was just curious if that was also true for these monarchs.
Michael Huffman:No, I don't think so, so are there butterflies that don't have those signals, that are also ingesting toxic plants? Is there a system where there is no link between what the insect is eating?
Jaap de Roode:I think pretty much all the butterflies that sequester toxins from their plants are advertising that toxicity.
Michael Huffman:And, overall, what percent of the species sequestered do you know?
Jaap de Roode:That's a great question.
Michael Huffman:I don't know Sorry.
Andrew MacIntosh:Someone out there can google it and write into the primate cast they're, you know, as an aside, the viceroy butterfly, which I'm sure you're familiar with.
Jaap de Roode:Oh, it's a mimic of the monarch but it is not toxic so okay, so it actually is, and so yeah, it used to be believed that the viceroy mimics the, the monarch, but the viceroy, which, as caterpillars, feed on willow trees, they're also toxic.
Jaap de Roode:So it's actually a interesting malarian mimicry where both are model and both mimic the other. Um that I will say the mimicry is extremely successful because if you google a picture of a monarch on the internet, a lot of the pictures you get are viceroys and I I have seen so many articles published in popular science magazines and also an advertisement campaigns where people instead of a monarch show a viceroys. Always there. I've been actually to mexico, to the overwintering sites, and they have a lot of little souvenir shops. When you go up to the overwintering sites, where there's literally tens of millions of monarchs, they sell t-shirts made in china and one year about half of the t-shirts show vice rose, not monarchs yeah, buyer, beware right I will say one more thing about the orange coloration, because I think when you started this podcast earlier, you said we're're going to talk about monarchs, but not the ones with the little crowns.
Jaap de Roode:Now, the name monarch actually comes from the Dutch monarch, so the Dutch royal family. I'm from the Netherlands myself, so I find this a fun fact. But the Dutch royal family actually comes from France, and so we have William of Orange, the founding father of the Netherlands, and so their color is orange, and so when you see our soccer team play, it's in the orange color. So the story is that when the Dutch made it to the Americas and saw this big, majestic, beautiful butterfly, that's where the monarch name comes from.
Andrew MacIntosh:Great, I had no idea where the name came from. I thought you were going to tell me they do wear little crowns when they're flying around, they don't? Only migrating butterflies maybe. That would create too much resistance in the air. We've diversed a little bit from the main, but so yeah. So, coming back to this idea of and I want to talk more about monarchs, maybe afterwards.
Andrew MacIntosh:Since we were talking about infectious disease and parasitism and behavior. I think it's a good place to kind of transition into self-medication and to do that I just want to read. So you published a paper in 2013 about self-medication in animals. This was a review, and the first line in the abstract reads the concept of anti-parasite self-medication in animals typically invokes images seeking out sorryokes, images of chimpanzees seeking out medicinal herbs to treat their diseases. And before I ask you, yap, to comment on that and where we go after that, I want to ask Mike, if you wouldn't mind, where is Yap coming from when he mentions that? So can you describe a little bit about why people might think of chimpanzees first?
Michael Huffman:Well, I think the first global attention, or at least in the popular press, about self-medication was started from some early work with chimpanzees. For better or worse that got a lot of attention and it kind of went off in a strange direction in the beginning. But I think most people associate self-medication with only large brain primates and tend to ignore that that should happen in every species on the planet.
Andrew MacIntosh:So just, I mean, I know we've had you on the podcast before and we've talked about self-medication, we've talked about your observations of chimpanzees, but maybe in the context of this conversation now you could just recount what like the major discoveries that you made with chimpanzees and self-medication.
Michael Huffman:Well, in the beginning I didn't go in to this topic on purpose. It happened quite serendipitously. I was following chimps. I was following a group of chimps in which there were several old individuals and young adults that I had picked as targets. I was actually looking at the role of old-aged individuals in chimpanzee society because it was at a time in the history of research on that population that we had old-aged individuals. We actually knew about how old they were. They were in their mid to high 50s and I was just starting my work with chimps, so that was a topic that seemed ripe for the picking.
Michael Huffman:Others were studying self-medication and they were talking about a behavior called leaf swallowing.
Michael Huffman:But there wasn't a lot of information about that behavior yet and they were making a lot of claims about it, so I I wasn't that interested in the idea, because it already is. A lot of question marks were coming up about the case being made for leaf swallowing and the people involved in that were also working at the same study site. But I happened to come across something that was different from that. That seemed like a stronger case for self-medication. So I followed up over a couple of days to see what would happen to that individual that ingested a plant that my local counterparts said was an important medicine for them, and so I began to try and figure out if that animal was indeed sick, and then what happened after ingesting the plants, and how similar was it actually to what humans were using the plant for? And then that kind of it. Just you know, it seemed like I was at the right place at the right time and I had to try and figure out what was going on.
Michael Huffman:So then I got interested and then I went back to leaf swallowing, to that first behavior and using the paradigm that I established, and began to see that in fact there was something there, but it wasn't at all what people thought in the beginning. So that at the time you know chimps, of course chimps, but nothing else can possibly be self-medicating Right.
Andrew MacIntosh:And.
Michael Huffman:I didn't buy that from the beginning. I didn't think chimps were doing it because they were necessarily smart, but because they're social learners and there's a lot of observational learning apparent in whatever they do. That's what I reported on first. But there was work going on at Kilt University with insects and talking about sequestering toxic compounds and stuff. So it seemed likely that it would happen in many different attacks. And the more I thought about it, I said any species that isn't self-medicating isn't around today. Because they couldn't defend themselves and then work like what Yap has done. It just really everything came into full circle and people really started actively looking and thanks to folks like Yap who are looking at the insects and are able to come at it from a different direction and kind of dispel some of these ideas that you have to be a large brain animal to do something is so much like us. But yep and I have had this conversation the humans are. We're not special at all. We're just an accumulation of every other animal that's that's evolved before us yeah, so it's a.
Andrew MacIntosh:I mean I know that you also had your moments there. There's some resistance to the ideas, but maybe we can come back to how broadly understood this field now is. But yeah, I want to turn back to you. So you know, in the in maybe in Mike's origin of this stuff and observations in Tanzania was still challenging to push the idea that apes might be capable of this. Yet it's somehow easier for us ultimately as a society to accept that those kinds of animals as you mentioned, large brain can are capable of things like that. But kind of linking back to what I asked earlier about how in some cases people might see that as more of in insects especially a manipulation of their behavior rather than something that they do in defense against parasites, so maybe you can maybe step in then and talk about what specifically you found with the monarch butterflies.
Jaap de Roode:Yeah, Well, I think what Mike said is very nice, that he kind of stumbled upon it, right, and it's not something he was planning to study. It was the same for me I didn't at all plan to study medication in monarch butterflies, didn't at all plan to study medication in monarch butterflies. But, like I said before, I was studying these, these parasites of monarchs, trying to understand why they're causing disease to the monarchs, which, by the way, means means that the monarchs cannot come out of their pupal case. They don't fly as well, they don't mate as well. So there's a lot of really negative consequences of this infection. But and we talked about the different host plants and how they use the chemicals to protect themselves against predators Now, as someone who studies parasites, you then think well, you know, predators are important, but parasites are more important than some of these you know infectious diseases everywhere.
Jaap de Roode:And so really starting to think, also based on other studies that were done in other systems, such as different moths, that that could benefit from the chemicals and other plants to kill viruses. And so really the question was, these chemicals that protect the monarchs against predators, do they also act against parasites? So that was the first study, and to rear monarch butterflies and different plant species, infect them with, with very controlled doses of parasites. And this is that we found out that some species of milkweed are medicinal. They really reduce the infection of the parasite. So it was very much a finding that that, you know, started just by studying the monarch butterflies and starting to think I never, you know the years before that studying the monarch butterflies and starting to think I never, you know the years before that, I would never have predicted that it's something I would study.
Jaap de Roode:But once we saw that these milkweeds have such a big impact on how sick the monarchs become, how infected they become, to me it was a natural question to ask. Well, we know that other animals can medicate chimpanzees and there was evidence for other species at the time too. So maybe monarchs can do it too. There definitely was resistance because when we wrote our paper up to show that these milkweeds can reduce parasite infection. In the discussion of the paper we speculated that maybe monarchs can take advantage of this, so when they're infected, maybe they can preferentially use the milkweeds that have more toxins and are more medicinal, and one of the reviewers that looked at our paper said that's just nonsense, there is no way monarchs can do that, and the editor told us to remove it from the paper, and so we did not, happily, but we did, and then it was a good motivator to say let's show them they're wrong.
Jaap de Roode:And so at that point I actually got a faculty position at Emory University, where I'm now, and so one of the first studies we did was put the idea to the test. And so we did two types of studies. The first one was to find out if caterpillars can self-medicate. So we infect caterpillars we have, you know, we offer them choices between diets, and it's natural diets. We grow all the plants in the greenhouse. We let them choose, found absolutely nothing interesting.
Jaap de Roode:These caterpillars just eat whatever comes in their way. As long as it's milkweed, they don't really care which species it is. But then we're really thinking about the adult butterflies. Because when you think about caterpillars, how do they end end up on a plant? It's because their mother laid an egg on that plant. So it's the mother that really decides what that caterpillar is going to eat, and I will say monarch butterflies. They don't really move that much when they're caterpillars, so it's the mother. They put an egg on a plant. That caterpillar is basically stuck there. That's where it's gonna have its caterpillar life.
Jaap de Roode:So then the question was can the mothers make a decision? So what we did then was an experiment where we had mothers that were either infected with parasites or uninfected. We mated them with males and then we set up big flight cages in the greenhouse at the university and in each cage we put a medicinal plant, a non-medicinal plant, let the butterfly fly around for two hours, let her lay eggs and then simply count the number of eggs. It's kind of cool that you can, you know, just counting that. That was our data and we found very, very strong preference for the medicinal plant by infected butterflies.
Andrew MacIntosh:So how many milkweed or how many different species of plant do you have in the experiment?
Jaap de Roode:So in this experiment we just had the two, two, yeah. So one medicinal plant, one non-medicinal plant. We chose the plant specifically because they differ in the medicinal properties but are very similar otherwise. Right. So they look the same, they're the same height, they have the same nutritional properties, so the same amount of carbohydrates nutritional properties.
Jaap de Roode:So the same amount of carbohydrates. Yeah, it's because you know you look at these preferences and you want to make sure that that what the preference is based on is that factor that you're interested in. In this case, that was the secondary chemicals that were associated with the medicinal effects so in nature.
Andrew MacIntosh:Then what is the I'm trying to? I don't really know anything about milkweed, so is that all within the the same genus that you have milkweeds, or are there multiple genera?
Jaap de Roode:It's mostly in one genus, asclepias, which is named after the Greek god of healing, asclepius, which is a very fun fact as well, and so most of them are within the genus. And in North America, where I do my studies, mostly most of the monarchs use anywhere up to 30 different species of milkweed, but you find oftentimes you find different species of milkweeds near each other. But also it's important that these females can fly long distances so they can easily move between different patches of milkweed. And the monarchs are selective. I've always been impressed. I may be hanging out in a milkweed patch, a butterfly comes along, she circles the plants, lands on it and then oftentimes flies away without laying an egg. So they're super, super selective. It's really intriguing and so, yeah, I think in nature they definitely have these opportunities to make these choices.
Jaap de Roode:And and you know, I, I think I I'm still intrigued by it, because what I find exciting about it is that these, these adult butterflies, already have parasites, and what the parasites do is they form spores on the abdomen of the butterfly.
Jaap de Roode:So this female, this mother, is already infected, because she became infected as a caterpillar, because the caterpillars eat up the spores that the mothers deposit on the eggs and the milkweed. Then the parasites go into the gut. From there they go into the tissues, from there they go to the abdomen of the butterfly and they just wait there for the mother to to lay an egg and then they get dropped onto the eggs and and the milkweed. So what that means is that the infected mother she's already infected. She cannot get rid of these parasites. She can also not stop the spread, because that's just a mechanical thing. When she lays an egg, some of these parasites just fall off and get stuck to that egg or to the milkweed. So really the only thing she can do is choose a plant that will reduce the chance of infection and reduce the disease symptoms for her offspring. So it's really, you know, mother knows best.
Jaap de Roode:That is how I like to describe it, she makes the decisions for her offspring, which is cool.
Andrew MacIntosh:It's very interesting. I noticed earlier when I was talking about self-medication, you made the very clear point of calling it medication and I think that's because of this right that you have intergenerational Absolutely.
Jaap de Roode:You picked up on that. So that's really what I'm trying to call it medication, to make it a little bit more inclusive. We see this with the monarch butterflies, but we also see it with other species such as ants and bees. They incorporate resin that they get from trees into their nest and they're not medicating themselves with that, they're medicating the rest of the colony with it.
Andrew MacIntosh:I guess this also applies to, maybe, bird parents that will fumigate their nests with different absolutely, absolutely, even, even there's examples recently of chimps treating others wounds and things, that that whole story isn't really clear yet.
Michael Huffman:but it's really exciting because it's a habitual behavior and it's one either applying a potentially meditative substance to a wound or even selecting the substance and passing it on to another individual, who then treats another individual, or they could even treat themselves. But it's just, the more we look, the more we realize we really don't understand yet Sure.
Andrew MacIntosh:And it's also interesting to think with chimps. I mean it's maybe for us, because we're so similar to them, it would be easier to imagine how they might detect the threat of parasites and the need to kind of act or counteract. So that would be in a therapeutic sense.
Andrew MacIntosh:There's also this idea that animals can preempt or prevent the acquisition of parasites through those kind of behaviors, but with the monarchs. What is our current understanding of how those mothers might detect the situation, how infected they might be and which milkweeds they should target because of that?
Jaap de Roode:It's a really wonderful question and it's something we don't really have an answer to yet. That it's a really wonderful question and it's something we don't really have an answer to yet, but it's very exciting is that there is another caterpillar species that we understand much better, and this is research done by by other people in the field, and they have looked at woolly bear caterpillars that often get infected with parasitoid flies. These are, you know, we can call them the kind of the aliens of the natural world right so these fly lay flies lay eggs on the caterpillar.
Jaap de Roode:The maggots eat their way into the to the caterpillar and then grow and then eat their way out, and so it's really like the alien movie in some ways. But research had shown that when these caterpillars eat more alkaloids in their food, that it reduces infection and it can actually kill these parasitoid flies. And then the researchers did experiments to show that when they're infected they eat more of those alkaloids, so they choose food that has more of these chemicals. And what is very intriguing about the system is that these caterpillars have four different taste receptors in their mouth and one of them is specifically detecting the alkaloids. And doing some very careful experiments with tiny little surgery and and electrodes they could show that when the caterpillars are infected they have the. These taste receptors for those specific chemicals were firing at much higher rates.
Jaap de Roode:So in a way they developed a, a taste for this medicine. So I think similar things may be going on in the monarchs. I already told you that monarchs often land on a plant and then they fly away or they lay an egg. So first they see the plant, they smell the plant, but a lot of it is based on taste. So they can taste the plant with their feet, with their abdomen, with their antennae, and then oftentimes you see them go away. So I think that the way I think about it is that disinfection changes their whole physiology and so they just become more sensitive to particular chemicals and probably more attractive to the plants that are more medicinal. Right, you know, and it's nice because I can walk into the greenhouse. I always tell my students you can blindfold me, take me to the greenhouse and I will pick out the medicinal plants for you, because I can smell them and so you?
Jaap de Roode:you know, if I can do it, I'm sure a monarch can do it better than me.
Michael Huffman:Incredible this is the exact same mechanism that I've read about with chinese medicine humans doing it to humans being their, their taste, perceptions or cravings or aversion when they get better. It's going on and we're trying to understand that in and other animal models. I think. To think that even that same mechanism is going on with the insects is tells us how old this behavior sure really is.
Andrew MacIntosh:Yeah, tells us how old this behavior really is. Yeah, and what so? Oe? I don't remember the actual scientific nomenclature of that parasite, but what kind of damage does it do to the adult monarch?
Jaap de Roode:Yeah, so the full name is Ophryocystis electroschera and that's why most people call it OE. It's a real mouthful. Yeah, so it's like I said earlier. So it infects the tissues and then, as the caterpillar, molds multiple times and then goes through the metamorphosis to form from the pupae to the adult. The parasites move toward basically what becomes the scales and the skin of the butterfly, and so they form there and that means that the scales cannot form. So you basically have little holes all through the skin of the butterfly and so they form there and that means that the scales cannot form. So you basically have little holes all through the the skin of the butterfly. So they lose a lot of liquids, they're they're really dehydrating and so, with very heavy infections imagine you have millions of those little lesions on your body.
Jaap de Roode:The butterflies get stuck to the pupal case. That means they will never come out as a, as an adult butterfly. They will never fly, never mate, they don't survive. Um, the ones that do come out don't live as long, and I think that also has to do with the, the loss of water. I think they also have damaged tissues, so they just don't do as well. They don't fly as well, which is really important for a butterfly that needs to fly up to 4 000 kilometers to overwinter, so that's a that's a big thing. And they don't mate as well.
Michael Huffman:So in fact, the butterflies are just not very successful at at mating and reproducing yeah, so when, when the larvae start eating the milkweed, they already have some of these parasites on them, does it kill the parasites themselves or does it prevent spread? Or what's the level of action? Or is it multiple layers?
Jaap de Roode:We don't really know the level of action yet. All we know is that when the medicinal milkweed and the parasites are ingested at the same time, that is when the medicinal milkweeds have an effect. If the monarch is already infected and you feed it medicinal milkweed, it no longer has an effect. So I think the plants really have a way to stop the parasites from infecting the caterpillar in the first place. Whether that's a direct toxic effect or whether it's through the microbiome, that's actually something we're investigating right now. But really kind of preventing the parasites from going in is really important.
Michael Huffman:Is there some kind of a fumigative effect of laying eggs on a plant like that, in addition to the effect of it ingestion by the larvae?
Jaap de Roode:That's a really good question. I haven't really thought about it. I think one way you could test that is to put the parasites on those plants, take them off again and see how mobile are they? Well, they're uh, they don't move themselves, but we we can pick them up. They're about 40 micrometers long, so you can have a little glass capillary, make a little tool and they will stick to it.
Michael Huffman:So they don't move around on the whole.
Jaap de Roode:No, no, no, no, they're just sitting there.
Andrew MacIntosh:Passively ingested by the catterpower when it moves around.
Jaap de Roode:Yeah, they're passive, they just get stuck there and that's it. But we can move them. We could do that. Yeah, it's a good idea.
Andrew MacIntosh:There we go. Yeah, you, it's a good idea. There we go, yeah.
Michael Huffman:You heard it right here folks Generating ideas on the private cast, yeah, Look forward to seeing that Before we go on. You were talking about the alien. You gave that image and it stuck in my mind. We had Sigourney Weaver, who dealt with the aliens in the insect world. Are we talking about Sigourney Weev, who dealt with the aliens in the insect world? Are we talking about Sigourney?
Andrew MacIntosh:Weevil, here we go.
Michael Huffman:Sorry.
Jaap de Roode:I don't even have an answer to that.
Michael Huffman:You're not supposed to.
Andrew MacIntosh:I could try and describe Yap's face right now, but I think we can move on.
Jaap de Roode:It assumes people know what weevils are.
Andrew MacIntosh:They're not monarchs.
Jaap de Roode:They're a little beetle yeah.
Andrew MacIntosh:Yeah. So I I'm curious and I want to come back to this later when we maybe close the interview about your the book that you're working on and you don't have to give too many spoilers. But I want to ask you, and especially since we have Mike in the studio with us, has there been anything related to to to medication in the animal kingdom that you've been researching that kind of blew your mind when you, when you read about it or or tickled you in some way?
Jaap de Roode:maybe you could just kind of relate one or two stories about that yeah, I think it's, it's all blowing my mind, you know, I I think it's just so intriguing and I think I'm still coming to grips myself that animals can do this. And you know, I think, like mike and I both said earlier, you know, when you make these discoveries, there's always this kind of initial resistance and it's something I have heard from everyone who has been studying self-medication or medication and species, um, you know, anywhere from birds to chimpanzees, to ants, to bees kind of this initial idea of there is no way. So I think we're still and I think that's the Western scientific tradition, where we like to think we're extremely special and so and we think of, you know, some animals being smarter than others. So, yeah, we can live with the fact that chimpanzees can do it. Insects cannot. So some really amazing, amazing stories.
Jaap de Roode:One of my favorite stories is that of finches and sparrows in mexico city, and I went to mexico city last summer, in june, to meet researchers there who had been studying these birds, what they noticed, that and and other thing they they didn't mean to study medication in these birds. They wanted to look at urbanization and see how birds adapt to urbanization. So when they building their nests, what do you find in those nests? Do they use natural materials or do they put plastic in, or you know other things that that people made? And what they found is that the birds put cigarette butts in their nests, and what they found is this kind of white, fluffy material. They didn't know what it was until it rained and they could smell the smoke and they said, okay, so these birds are picking up these cigarette butts, pulling them apart, putting the little fibers in their nests. Why are they doing this? And so they started with this beautiful correlational study, finding that nests that had more of these cigarette butts had fewer parasites. And so we talk about ectoparasites, which is lice and mites and ticks.
Jaap de Roode:And then you know, so that gave the idea oh, maybe these birds are putting these cigarette butts in their nests as a as a medication, as a fumigation in this case. And then they followed up with a beautiful experiment where they said, okay, well, we want to actually test this idea. So they made artificial nests, artificial linings for nests, and then they either added live ticks that suck the blood of the birds, or they added ticks that were killed, or they added nothing as a control, and they found that the birds with the live ticks, collected a lot more cigarette butts and also found that those chicks were doing better. They grew better. So it's a really intriguing example, right, because it takes you full circle the idea that animals cannot do this, and you know. And then you find that animals can do it and in some ways we're even helping them by, you know, littering these cigarette butts.
Andrew MacIntosh:We should take a moment to intervene, though, and say that the primate cast in no way, shape or form, supports cigarette smoking Absolutely.
Jaap de Roode:Yeah, I think the cigarette industry. But what it showed to us, I think, is that there is this, these abilities that these animals have to find these medicines in nature, and they have some some mechanisms by which they can recognize them. But I did ask that question because, you know, there, for example, at emory university, where I work, there are no cigarette butts because we have a cigarette ban on campus, so our birds could never do this. So I I asked, kind of ingest fun, you know what, if you going to take care of these cigarettes and make people stop smoking, is that bad for the birds, right? But the researchers said no, because they're so adaptable. What they can do instead, and what a lot of birds do, is use aromatic plants, and so they can find tobacco plants, they can find other plants that have the same function as their cigarette butts. It just so happens these birds that live on a university campus in Mexico City they're, you know, surrounded by these butts, so they only have to fly 10 meters to get their medicine rather than fly 100 meters.
Andrew MacIntosh:So they'll do that. So, if anything, this is still reinforcing the idea that we should take better care of nature so that the animals can sort it out themselves.
Jaap de Roode:Yeah, because you know, the cigarette are not not harmless either for the birds. So they actually have some defects in their blood cells.
Andrew MacIntosh:So it's it's not you know, we all know smoking is bad.
Jaap de Roode:It's also bad for birds yeah so yeah, I, I agree with you. It reinforces the idea that you know it. This is a cool example, but wouldn't it be nicer if the birds could just use the plants if they were still available, or we can replant them and make sure they can use those? So yeah, but yeah, that whole thing has blown, blown me away. I think it's such a wonderful example what, mike?
Andrew MacIntosh:what about? I mean, you've been in this game for quite a while and you've seen a lot and you've you've been an advocate for a lot of different ideas that that folks around the world have had about self, about self-medication and medication in animals, and so, um, maybe I'll ask the same question to you, like what kind of over the years, apart from your original observations of of chashka chimpanzee, but what has kind of most surprised you as we've gone forward and learned more about this area?
Michael Huffman:I think what amazes me most is how some behaviors repeat themselves in so distant taxa. Snow geese, grizzly bears, japanese monkeys, gibbons, chimpanzees, bonobos, gorillas, cats, dogs are all swallowing leaves or grass and they're all expelling parasites. Obviously, it's not something that's only found amongst chimps, you know. It's just the fact that these simple strategies have been reinvented or have just been maintained all across the evolution of animals. It's amazing, and it's also nest fumigation Animals that build burrows and stay in the same place for a long time. They're doing the same thing, and Yap brought this up.
Michael Huffman:I forgot what Yap brought up, but what I lost, my train of thought, but the fact that, well, okay, in Mexico City it's easier to get cigarette butts or the filters from the cigarette and pull that out and put that in the nest. But those birds in Mexico City are identifying, in the same way that birds in France or the birds in Africa and North America are, to certain smells and certain things that that tickle their brain, tickle their instincts to to add in into the nest when they're facing a certain problem. They know that this will relieve symptoms. They may not know the species of tick that are in their nest, but they know what the consequences of having something like that in there. And that mechanism is in there from humans all the way down to monarch butterflies, and I think that alone should convince anyone that, no matter what species we're thinking about, they're all self-medicating.
Michael Huffman:If you just think of it as a very simple predator-prey system, they don't have to be lions, they don't have to be something really big and loud for us to have to avoid them. They can be inside of us, they can be on our mothers and we're getting them when we're born. Um, it's a very simple, very basic principle and, and hopefully more, if we can get people to think of it from that perspective, we'll have a lot less problem publishing papers and I think in the end, everyone will will accept that this is so. You know, it happens a lot in science. I think this is so simple. Why didn't we think of it earlier? Or, of course, this yeah, of course that's what's going on and I think we're almost there from my perspective.
Andrew MacIntosh:I mean it looks like you gained a lot of traction. So and I do like the point you make I mean the grasses, for example, that those leaf swallowers are using would be different everywhere that you find them, yet the concept is kind of the same.
Michael Huffman:And the principle of the leaf is very similar. It's not just the behavior, but it's the leaves that they're selecting, and it's all for a specific function.
Andrew MacIntosh:Yeah, super interesting. And I think all three of us sitting at this table can agree that parasites are far more important and interesting than predators. Yes, so I appreciate you. You mentioned that earlier.
Jaap de Roode:Yeah, I, I was gonna say you earlier asked you know things you have found that are really interesting or tickling. You know your, your interest and you know I. I think one thing that we haven't mentioned yet is just the, the applications that we can get from that would be my very next question okay, perfect.
Jaap de Roode:So you know it's I. I'm really a basic biologist, I love nature and I just love understanding these things. But at the same time it's also so interesting to learn how much humans in the past have already learned from animal medication. And you know, I think one thing that we haven't emphasized yet is that the things that Mike has discovered, the things that I have discovered, the things that a lot of us have discovered, are really rediscoveries. And when you look at the traditional knowledge and traditional healers, they have often looked at animals and, like Mike said earlier, earlier, you know, really understanding what the chimpanzee was doing, based also on the knowledge of the. The traditional healer that was working with mike and guiding him through the forest really tells you that we have lost some knowledge that we are now regaining. But when you go back and you look at it and you find out that people have looked at animals, learned from them and created medicines.
Jaap de Roode:There's even some indications that the drug aspirin, which comes from the bark of willow trees, that has its origin with bears. Bears have been a really good example for humans all over the Northern Hemisphere as a master of medicine. A lot of shamans would dress up or behave like bears, get in trance-like states to be like bears and dream of bears and bears. What they do is, after they come out of hibernation, they're completely. You know. They have been in hibernation for months. They're stiff, they're in pain. First thing they do is eat the bark of willow trees and get all that salicylic acid that is an anti-inflammatory, and so and that's just one example, and I think there's plenty of other examples where we already have learned from animals, without some of us in the West remembering it but also opening up new avenues, you know, finding out about new drugs that we may still discover by looking at animals, which I think is a really interesting possibility.
Andrew MacIntosh:Yeah, I think you made a. You gave a.
Jaap de Roode:it's on your website, but you gave a six minute TED talk about this, and I think you closed your talk by making a prediction, which was that one day we'll be using medicine discovered by butterflies and yeah, you know, I think maybe we already are, without us knowing it, and I think a lot of medicines that we use, even today, a lot of the drug discovery is based on plants and a lot of the initial indications. There's a whole field of ethnobotany where scientists talk to traditional healers and learn from their knowledge, but the question is, where does that knowledge come from? I wouldn't be surprised if a lot of that knowledge came from animals, maybe even some butterflies.
Michael Huffman:I might do.
Michael Huffman:I've often been asked when I give talks like this is there a plant out there that is now used as medicine by the research with chimps? And I always used to give examples. Well, bernonye is a very good example, but it's not something you can buy across the counter in a Western pharmacy or in a drugstore. But I started thinking more and more and I said the question should actually be redirected back to those people. Tell me a medicine that wasn't derived from plants, that animals weren't using before people were on this planet. So everything we use basically is derived from nature. So that means from the animals and from the plants.
Michael Huffman:But to specifically think of this medicine coming from butterflies. I think would really be cool and it would maybe bring us all a little bit closer together on the planet not just humans, but everyone.
Andrew MacIntosh:Yeah, so I, there's so many transitions I wanted to kind of make from that last little bit that you said. So this is going to come up as a little bit awkward, but two things I think we can close out, uh, after that. But there's two things I wanted to I wanted to talk about while you're here in the studio, yeah, and the first one is monarchs, uh, and migrations, because I think that topic itself is, when people think of monarch butterflies, apart from the the visually striking orange, uh, coloration they have the migration is another, another huge thing that comes to people's mind.
Andrew MacIntosh:And then maybe we can just close with something that's very related to what you just talked about, which is the messaging behind self, not just medication but just in general science messaging. And you know, I wanted to catch your thoughts a little bit on the process of writing a book for those in the audience who may be interested in that process.
Andrew MacIntosh:We all love reading popular science books. It's a great way to kind of engage with the material, and so, if you don't mind, maybe we can just close with those two things. So first, monarchs. So you've been studying monarchs now for a couple of decades I suppose.
Jaap de Roode:Since 2005.
Andrew MacIntosh:Getting up there and what is so you came at it from this idea of being interested in parasites, infectious disease and ecology, but what has really struck you about studying monarchs and then maybe we can get into the migration?
Jaap de Roode:I think the thing that surprised me the most was how little we know about monarch butterflies. Little we know about monarch butterflies you know for, such as popular species. You you google butterfly on the internet or you see any advertisement campaign. Even I was in the netherlands a few summers ago, rented a bike at a shop and their advertisement featured a monarch butterfly. That makes no sense. There are no monarchs in the netherlands there is there.
Jaap de Roode:There is a history with our royal family, but I I thought you know, for such a popular species we know a lot more than than we do, and it's still intriguing to me. One of the the major questions is their migration. How do they know where they're going? Or, to rephrase that, do they know where they're going? I mean, that in itself is a really interesting question.
Jaap de Roode:So monarchs that are are born as caterpillars toward the end of the year, so the end of the summer, in southern Canada, the northern United States. They do not develop into butterflies that are going to breed and produce more caterpillars. They're developing into migrant butterflies and so when they're adults they just start flying south and then after some time they make it to overwintering sites in central Mexico, high up in the mountains, in particular trees. From year to year they go to the same places, but every butterfly only makes the journey once, and in fact most butterflies never make the journey, because what happens in the spring is the butterflies go north, they lay eggs and it's the next generation that goes further north and then yet another generation that makes it all the way to canada. So it's only one in three or four generations of monarchs that migrate. They only migrate once, so they have no way of learning from others. There are no, you know, older butterflies there to guide the way, so it is completely innate.
Jaap de Roode:They, they fly south, they end up there and the question is do they need to know? Do they know where they're going, or are they just flying south and the landscape brings them there? That's something we don't know and it's it's really intriguing, um, that you know, for a species so well studied. That's something we didn't know, and so that's still something that a lot of people are working on. We are working on that question right now. I think it's a very difficult question to tackle, but, yeah, most surprising thing to me was that there's so much we still need to understand.
Andrew MacIntosh:Yeah, that's really and also important. So, especially with climate change, I know that for monarch butterfly monitoring there's big citizen science projects where people report, basically when they arrive and we we have really great data. Because of that it's beautiful, yeah, but so what and I think I've read that you've written this OE parasite as well it seems to be increasing.
Jaap de Roode:Yes Over time.
Andrew MacIntosh:And I'm wondering you said earlier in this interview that that has an impact on migration so what is the kind of current status then, from your perspective, of considering climate change, considering just habitat? I mean environmental change too, and urbanization yeah, lots of everything. And now the parasite story lots of challenges so parasite prevalence has increased.
Jaap de Roode:So until about 20 years ago, maybe one in a hundred butterflies were infected with this parasite in North America. Now it's about one in 10. So that's a lot. Now, given that the parasite reduces their ability to fly, it really kills a lot of monarchs during that migration. And that's actually interesting because in some ways this migration really gets rid of these parasites. So it's in a way a treatment, because the most infected butterflies do not make it.
Jaap de Roode:So you get rid of a lot of parasites from year to year, and so the population starts kind of at a low level of parasitism again the next year. But on the other hand, for an individual monarch butterfly that's infected, that butterfly is not going to make it to Mexico. It's not going to survive, it's not going to reproduce, right. So when we see this increase in parasite prevalence, it's really detrimental to the migration, and so we did a calculation in a recent paper suggesting that tens of millions of monarchs die of this parasite on their way to Mexico every year. So that's a big deal. At the same time, yeah, climate change is going on, and so there is a lot more milkweed growing in the United States now that doesn't die back in the winter. That means that monarchs can reproduce throughout the year and that increases that parasite prevalence as well.
Andrew MacIntosh:So you have sedentary populations. That's right, yeah, yeah.
Jaap de Roode:So yeah, and so you know the things we can do about that. You know, like you said earlier, there are a lot of citizen scientists that work on monarchs. And actually brings me back to another thing you asked you know what has surprised you about monarchs? I think it is so amazing that millions of people rally around an insect. I mean, you know, and I'm still I'm still in Proveco to monarch butterfly festivals. People dress up like monarchs, thousands of people come to these festivals, people love butterflies and I think it's great because you know that's an insect and generally people like fluffy animals, but not these insects.
Jaap de Roode:So I think that's great and that also means we can use them as a rallying species. I like to call them the ambassador of the insect world. People rally around monarchs, not the average weevil or cockroach or whatever, but by protecting monarchs we can protect all the other insect wildlife too. So I think you know recreating habitat you mentioned urbanization earlier. So building pollinator gardens that include plants that monarchs can use, but native ones that die back in the winter, those are the things that we think are important.
Andrew MacIntosh:I think I read recently an article about this in the us, where insects don't have any kind of status, of conservation status, for example, so there's really no body that can work towards supporting their most, yeah, most, state legislatures don't have, or or state constitutions have defined butterflies as animals and therefore they're um, they're hard to to regulate allegedly, yeah, yeah and I know that you also work on bees.
Andrew MacIntosh:We're not going to get into that because that's a whole other topic maybe we'll save it for around two of the podcast yeah but uh uh, also very important that we we change our ideas about these organisms to do more to protect them Bees obviously being incredibly important for our food security.
Jaap de Roode:And also monsters at medication.
Andrew MacIntosh:Yes, so maybe last thing then I just want to talk a little bit about science communication. You noted earlier in this interview that when you were doing more journalistic work, you also have a background in science writing, I believe, and now you're working on this book.
Michael Huffman:So can you maybe talk a?
Andrew MacIntosh:little bit for anyone out there who is maybe a young academic or it might be interested in science communication. How does that work for you? I mean, do you recommend people try and get some kinds of certification in science writing? Has that helped you a lot? And then, how did you come to the idea of writing a book about medication?
Jaap de Roode:So definitely having done science, journalism. So I started during my undergraduate degree. I actually took a course in it and then I did a lot of freelancing. I did a full-time year of freelancing and then even during my PhD I still wrote, maybe once a month wrote an article. I think it's incredibly useful. I think it really helped me get my scientific papers written. Just the idea of I just need to get this done you know, working with deadlines in the popular press, you cannot sit around forever thinking about your opening sentence, you just have to get it done. So getting that familiarity with writing was super helpful. I think the best compliment I ever got was when I wrote a thesis chapter draft and one of the professors on my committee said that it was too easy to follow. It read like a journalistic article. I said, well, good, that means that it was easy to read. So I think it's very, very useful and it was fun. But it's also helped with science and you know, within our scientific fields we also have to popularize right.
Jaap de Roode:Yes we talk to experts in the field, but no one is as expert as we are on the specific things we do.
Jaap de Roode:So when we give a talk or make a poster, write a paper, we still have to try to convey the message in the best possible way, and so writing the book now is really my way of going back to my initial passion for science writing.
Jaap de Roode:You know, getting into the scientific career, I I still wrote scientific popular science articles during my ph, but then, since then, the research took over and the teaching took over and the research administration, and so this was for me.
Jaap de Roode:I had a half year sabbatical at Emory and I said this is the time to go back to that and write something very exciting. And you know, by that time I had developed a strong interest in the topic and, always talking about it, never found anyone that didn't find it interesting. So I thought it's a great topic for a popular science book where we can talk about this cool nature but also talk about, but we can learn from it and maybe create yet another rallying cry to conserve nature, save our planet. You know, even even the thought of replacing part of your green front lawn with some wild plants, pollinator plants, medicinal plants, you know providing medication opportunities not just for the insects in your garden but for your pets, your cats and your dogs, right, and then maybe for our future drug discovery. I think it's a, it's a really cool idea yeah, do you have.
Andrew MacIntosh:So you mentioned um writing for, for for the media. You have deadlines and so you're basically doing it all the time since your phd. You hadn't done it very much, but did you try. Do you journal, for example, or did you try to find ways to keep the practice up in that interim?
Jaap de Roode:no nothing no, I mean, you write so much in this job. I I find it, I found it hard to uh to keep on doing that right, yeah so spend a lot more time writing papers, grants and edit student papers and everything and that's also fulfilling. Yeah but I was ready to, to go back to the more kind of creative writing, right and uh, starting with that sense of wonder, yeah and being less restricted by the the formats of a scientific journal right was there any um like leading up to this, this decision to take it on?
Andrew MacIntosh:were there any uh books that you yourself just really enjoyed and kind of wanted to model yours after that you can think of at the moment?
Jaap de Roode:I. I've always loved reading popular science books. I think one of my friends from the Netherlands he was a postdoc in the lab where I was an undergraduate student. His name is Menno Schildhuisen. He has written multiple popular science books and the book that kind of inspired me, I think, is a book called Darwin Comes to Town where he talks about how species are adapting to urbanization and urban life and it's a combination of really talking about the science but featuring the people who do the science in that book. And I think that's something I'm trying to do as well, because I like to show people that science is a human enterprise and different people do it differently and people are driven by these different ideas. So I'm trying to feature the people and the places as much as the science, and I think that was inspired by that book.
Andrew MacIntosh:Great. Well, we're definitely happy that you were able to, you know, follow through on that and come here and visit Mike and Inuyama and have a chance to talk with you here for the PrimateCast aptitude. Thank you very much for joining me on the primate cast. Thank you so much, mike. My pleasure. Great to have you in the studio as well always my pleasure.
