Zombie ants

Daniel and Kelly talk about the science behind the "zombie ants". See omnystudio.com/listener https://omnystudio.com/listener for privacy information.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  This is an iHeart Podcast. Guaranteed Human. Hey, I'm Niall Rogers. This fall, I'll be driving across the country, meeting some of today's coolest and most fascinating artists. We'll explore the stories before the moments that changed everything. Because every musician remembers the moment where it all began. Experience Before the Moment, a Lincoln original series on the iHeart Radio app, YouTube, or wherever you get your podcasts.

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• 1:52Kelly Weinersmith?

  The fungus known as Ophiocordyceps may be the most famous fungus in pop culture right now. I know, it's a low bar, but still, it's pretty cool. The Girl with All the Gifts, The Last of Us, and a host of other books, movies, and video games feature this behavior-manipulating fungal pathogen. But what does it really do? How do the zombie ants behave? And what do we know about how the fungus hijacks ant behavior? And yes, at the end of the episode, I'll speculate on whether Ophiocordyceps could jump from ants to humans, hijacking our behavior along the way. Welcome to Daniel and Kelly's Manipulated Universe.

• 2:44Daniel Whiteson?

  Hi, I'm Daniel. I'm a particle physicist and I like to think of myself as a fun guy.

• 2:50Kelly Weinersmith?

  You know, Daniel, you have made that joke before.

• 2:52Daniel Whiteson?

  It's too good.

• 2:53Kelly Weinersmith?

  I know. It is. It is good. It's good. I'm Kelly Weiner-Smith and I'm a fun gal.

• 3:03Daniel Whiteson?

  And today, we're talking about how funguses make us friends or make us more fun.

• 3:07Kelly Weinersmith?

  Um, no.

• 3:09Daniel Whiteson?

  Or make us act weird and climb to the tops of things.

• 3:12Kelly Weinersmith?

  Or something else entirely. Yes. How ants get manipulated by a fungal pathogen, but probably, well, wait till the end. We'll see what we think about people.

• 3:22Daniel Whiteson?

  I do like the idea that some of our weird behavior can be attributed to some part of us that's not really part of us, you know, that we can say, oh, that's just the fungus in my brain.

• 3:32Kelly Weinersmith?

  Yeah, absolutely. So when I started my PhD, I was studying why organisms behave the way they do. So I was into animal behavior and I've came across the Toxoplasma gondii literature where that parasite that lives in our brains is associated with weird behaviors. And I got absolutely hooked on this idea that not all of our behaviors are attributable to our decisions, that maybe it's like a group effort, the person who we end up being and that, you know, the microbes in our gut influence our behavior and the parasites in our brain influence our behavior. And I find this topic totally fascinating.

• 4:05Daniel Whiteson?

  But in some sense, that's freeing because it tells you, oh, I don't make all my decisions. In another sense, that's terrifying because like, oh my gosh, I don't make all my decisions. And Katrina would probably be like, no, that is who you are. Your microbes are part of you.

• 4:18Kelly Weinersmith?

  Yeah, no, I kind of agree with that take. But one thing that I think is fun is that one of the big names in the field that studies how Toxoplasma gondii impacts human behavior, his name is Yaroslav Flager, apologies for my, you know, forever bad pronunciations. He got into this because he was like, you know, I act kind of weird, sort of like not like other people. I wonder if I have a brain infecting parasite. And he gave himself a test and he did. And this set him off on the path of like, wondering about how toxoplasmosis is associated with human behavior. It's an interesting question.

• 4:52Daniel Whiteson?

  Is it possible to have a fungus in your brain that makes you eat cookies too late at night?

• 4:58Daniel Whiteson?

  Can I blame that on somebody?

• 5:00Kelly Weinersmith?

  Daniel, that is you. No, that's you, Daniel. That's you. And just for clarification, Toxoplasma gondii is not a fungus, but there are a variety of different parasites that can live in human brains, unfortunately.

• 5:11Daniel Whiteson?

  So if I do have a parasite, it's probably like, Daniel, stop eating cookies. Those are bad for you and bad for us.

• 5:16Kelly Weinersmith?

  Yeah, maybe.

• 5:17Daniel Whiteson?

  Well, I'm overruling them.

• 5:19Kelly Weinersmith?

  I don't know that cookie consumption as an implication of brain parasites has been studied thoroughly, so I don't want to go on the record.

• 5:27Daniel Whiteson?

  It's so easy to get to the edge of knowledge in biology. Wow.

• 5:31Kelly Weinersmith?

  Yeah, we're not asking the right questions.

• 5:34Daniel Whiteson?

  Why does mainstream biology want to shut this question down, Kelly?

• 5:39Kelly Weinersmith?

  Yeah, I don't, I don't know, Daniel. Not a great question. But you know what is a great question?

• 5:44Daniel Whiteson?

  Give us a transition.

• 5:46Kelly Weinersmith?

  Yeah. What is a great question is the question we asked our listeners.

• 5:50Daniel Whiteson?

  What was that?

• 5:50Kelly Weinersmith?

  That was, what is summit disease? And if you would like to answer questions for us, send us an email at [email protected] and we'll add you to our list. So let's hear what our listeners had to say in response to what is summit disease.

• 6:07Speaker 04

  Summit disease is an affliction that occurs when you can't stop hiking to the top of mountains and it causes you to neglect the rest of your life.

• 6:17Speaker 05

  I think it's a brain disorder that makes you wave at dead bodies on the way up Nepalese mountains.

• 6:22Speaker 06

  The sickness individuals get when they are at a high altitude and climbing mountains, for example.

• 6:31Speaker 07

  I think you're referring to high altitude sickness. Mountain climbers, when they go up above a certain elevation, can get lack of oxygen, pulmonary edema, cerebral edema, et cetera. No bueno.

• 6:42Speaker 08

  This is a disease similar to OCD. You have to walk around adding things together.

• 6:49Speaker 09

  I could be mistaken, but I believe it is when an avid climber gets the impulsive need to tell the people around them all of the mountains that they have summited.

• 7:00Speaker 10

  It seems like summit disease could be when I go on top of a mountain and my fingers swell up and I get tired easier, except for way, way worse.

• 7:08Speaker 11

  Summit disease is when you, after a really long climb, get to the summit and then the mountain gods invade your brain, make you do bad stuff. I don't know.

• 7:17Speaker 12

  When you're, you reach the summit of a mountain and you can't stop throwing up because you're so sick of looking at mountains.

• 7:25Speaker 13

  I think that's when you're hiking and you've reached an altitude or elevation where the air gets thinner and you start to get headaches and feel nauseous and stuff like that.

• 7:33Daniel Whiteson?

  So I also would have guessed something that happens to you at the top of Mount Everest.

• 7:37Kelly Weinersmith?

  Yeah, that is a totally reasonable answer. We have a very smart audience, but actually, this is something that happens to insects and not to humans. And I'll also note that I laughed out loud at the, you have to walk around adding things together. It took me a second to put that together and be like, oh, sum it, sum it, adding. And I laughed out loud. So anyway, thank you for that, that moment of revelation there.

• 8:01Daniel Whiteson?

  Well, I love this opportunity to dig into the real science that's sort of underlying some Hollywood myths. You know, there are these fun stories you hear sometimes in science fiction, but often these are inspired by actual and really fascinating on their own stories of what's going on out there in nature. So tell us, Kelly, what is the story that inspires all these Hollywood tropes?

• 8:25Kelly Weinersmith?

  Well, so let's start with what is summit disease? And summit disease is a thing that happens to a lot of different insects that are infected by fungus or by viruses. And the deal is that either the fungus or the virus gets an insect to climb high and then it gets the insect to stay there instead of like coming down for the night. And then they like cling in some way and they stay up high. And from that location, they then die and they rain infectious particles down on their other insects below.

• 8:54Daniel Whiteson?

  Do they like explode?

• 8:55Kelly Weinersmith?

  Uh, you know, explode might be overselling it a little, but like, so for example, there's a virus that infects caterpillars and caterpillars go up during the day to like eat leaves. And then at night, they usually come down and they like hide. But this, when they're infected by this virus, they climb up and they stay there. And then they die and they sort of liquefy and they rain virus particles down on the caterpillars that are below.

• 9:19Daniel Whiteson?

  They drip gooey infected caterpillar down.

• 9:21Kelly Weinersmith?

  They do, yeah.

• 9:23Daniel Whiteson?

  What a weather forecast.

• 9:24Kelly Weinersmith?

  That's, oh, yeah, cloudy with the chance of, um, virus soup.

• 9:28Daniel Whiteson?

  Caterpillar bits.

• 9:29Kelly Weinersmith?

  That's right, gross. But this also happens, there are like quote unquote zombie flies that are infected by a fungus and they'll climb up and they'll even like, they'll climb up and then they'll spread their wings out to the side so that when they die, the fungus can come out of their back and their wings don't get in the way. And that one does, it's sort of like shoots like cannonballs out of their back down at the like flies below. And so

• 9:53Daniel Whiteson?

  Oh, my gosh.

• 9:53Kelly Weinersmith?

  This is a pretty common strategy you see in viruses and fungus that infect insects that want to go on to infect more insects.

• 10:01Daniel Whiteson?

  It's fascinating because you say it does this so that this other thing happens, which implies that there's some sort of high level decision making. But I know it's all like low level mechanistic, blind evolution. So I'm curious to hear how all that comes together and how the whole process comes together. You know, it's one of these examples of like a complicated thing where you need lots of pieces all together to accrue the benefit, which always makes me wonder how it came together in the intermediate stages.

• 10:29Kelly Weinersmith?

  Yeah, and this is why the zombie ant system is one of my favorite systems to study. So, so this phenomenon where some parasite or pathogen hijacks the behavior of its host so that the host is doing something that benefits the parasite.

• 10:42Daniel Whiteson?

  Right.

• 10:43Kelly Weinersmith?

  We call this manipulation. And it's really tempting, and we've talked about this in other episodes, it's really tempting when you see a host behaving weirdly to be like, oh, that's manipulation that must benefit the parasite in some way. But while it's easy to come up with a story, it's harder to test that. And every once in a while, we'll have a story where it sounds like the pathogen was benefiting, but when you look into it, it's not. So mosquitoes, when they're infected by malaria, right after they get infected by malaria, they bite less. And there's a period where after the mosquito takes a blood meal that has malaria, that malaria is sort of maturing and can't transmit yet. So if the mosquito took a blood meal and got slapped by a hand, then the malaria would die and so that wouldn't be good.

• 11:27Daniel Whiteson?

  Mm hmm.

• 11:27Kelly Weinersmith?

  You know, in a very anthropomorphic way, the malaria quote unquote doesn't want the mosquito to get killed or to take blood meals at that point.

• 11:34Daniel Whiteson?

  While it's still developing and preparing.

• 11:36Kelly Weinersmith?

  That's right. But once it's ready, once it's in the mosquito salivary glands and could transmit to a human, those mosquitoes start biting even more. And so this was thought of as manipulation. The parasite is protecting the mosquito and itself until it can transmit. And then, once it transmits, it gets the mosquito to bite a lot more. And that really sounds like it would be good for the mosquito.

• 11:58Daniel Whiteson?

  It's a good story.

• 11:58Kelly Weinersmith?

  It's a great story, but it turns out that if you activate the mosquito's immune response by, for example, killing bacteria and then putting those dead bacteria into the mosquito, it will do the same thing.

• 12:11Daniel Whiteson?

  Even though it doesn't benefit that bacteria.

• 12:14Kelly Weinersmith?

  That's right. Well, yeah, the bacteria are dead. They're just making the mosquito's immune system activate, and this is what the mosquito does. So it could be like when the mosquito's immune system is activated, it just kind of wants to hunker down. It's not as fast, it's feeling kind of crummy, it's just taking a nap before it's ready to go again. And so that's probably not manipulation. It doesn't look like the malaria is doing that. That's something that's driven by the mosquito.

• 12:37Daniel Whiteson?

  It could still be in response to the malaria, right? When it gets infected, it does this, and the malaria can benefit from it. You're just saying it's not something that the malaria has specifically engineered to benefit itself. It's something the mosquito is already doing.

• 12:49Kelly Weinersmith?

  Yeah.

• 12:50Daniel Whiteson?

  Or would otherwise have done. Fascinating.

• 12:52Kelly Weinersmith?

  Exactly, yeah. So trying to figure out who's driving the change in the behavior and how it actually benefits is much harder than coming up with the initial story.

• 12:59Daniel Whiteson?

  Yeah.

• 13:00Kelly Weinersmith?

  And so what I love about the zombie ants is that this system has been studied in quite a bit of detail. And so we're actually starting to nail down the various pieces of what's happening here.

• 13:08Daniel Whiteson?

  Well, that reminds me of our conversation with Capo Hen, and we were talking about science and storytelling and how much of science is storytelling is saying this happens because of that, because of this other thing. And sometimes the statistics or the mechanics of it don't always support that. It's just, we are trying to extract stories because stories make sense to us.

• 13:28Kelly Weinersmith?

  Yeah, and I think sometimes we get a little carried away with our stories and we don't necessarily have facts to support every piece of the story. And so this system is nice because almost every piece of the story has been dug into to some degree.

• 13:41Daniel Whiteson?

  All right, then carry us away to a story, Kelly. Tell us about manipulation of ants.

• 13:46Kelly Weinersmith?

  Okay, you are a little ant, walking around on the forest floor.

• 13:52Kelly Weinersmith?

  Unbeknownst to you, you have stepped on a fungal spore. The fungus gets in between the cuticles and invades the body.

• 14:00Daniel Whiteson?

  Wait, I'm a little ant and I have cuticles still?

• 14:02Kelly Weinersmith?

  Exoskeleton. I think they call that cuticle. I don't study ants, man.

• 14:07Daniel Whiteson?

  What's the name of my ant? Am I danchel?

• 14:11Kelly Weinersmith?

  Yes, yes, you're danchel.

• 14:14Daniel Whiteson?

  Walking around the forest with my little cuticles. Okay.

• 14:16Kelly Weinersmith?

  So, poor danchel has picked up a fungus. Danchel doesn't realize that he's infected. Actually, if you're a forager, you're probably a female. So, anyway, this is not working great. But anyway, so the little ants, the little ant has gotten infected. Doesn't realize it. It goes back to its nest. The nestmates don't seem to realize that it's infected either. But a couple of weeks after it initially gets infected, it starts walking out of the nest. This nest is up in a tree and it starts stumbling down. We call it a drunk walk. So, it sort of starts stumbling down the tree and then it walks along the forest floor and it climbs up a stalk. And this is in the tropics. It climbs up a stalk or a stem of something to about 20 plus or minus 2 centimeters.

• 15:00Kelly Weinersmith?

  This is happening at solar noon and on the like north northwest side of the plant, it goes underneath a leaf, bites down with its mandibles. These are like the pincy mouth parts it has. And then it will never move again and it dies.

• 15:13Daniel Whiteson?

  Wow. So, it has to go all the way down the tree just to find the stalk to climb up?

• 15:17Kelly Weinersmith?

  Yes. Yep. Just to find the stalk to climb up. And then the ant dies and a stalk comes out of the side of its neck and it forms a ball at the sort of like top-ish part of the stalk. And then fungal spores rain down on the forest floor and the cycle starts again.

• 15:33Daniel Whiteson?

  The stalk is not from the plant. It's some like weird fungal thing?

• 15:36Kelly Weinersmith?

  Yeah, it's the fungus makes it. So, the fungus, now that the ant is dead, it starts using all of the ant's internal body parts and converting it into fungus. And it makes this stalk that rains fungal spores down and the cycle starts again.

• 15:48Daniel Whiteson?

  This sounds like a science fiction horror movie. You're telling me this is happening on our planet all the time?

• 15:53Kelly Weinersmith?

  Oh, my. It is. And okay, so what blows my mind is that that is so specific. Like, one of Zach's gripes about me as a human being is that I am really bad at estimating distances. And like, he'll be like, well, what's, you know, do it about 2 feet from here. And I'll be like, I have no idea what you mean. I can't do that. Whereas this fungus by remote control is getting the ant to about 25 centimeters, plus or minus like two and a half centimeters. I think earlier I said it was 20, but it's more like 25, which is very specific. And so how does that happen? We're going to get to our best guess right now at how that happens a little bit later in the show. But it's amazingly specific.

• 16:32Daniel Whiteson?

  Wow.

• 16:32Kelly Weinersmith?

  But now it's worth mentioning that, okay, that is a story from Ophiocordyceps unilateralis.

• 16:38Daniel Whiteson?

  And just to complete the loop, it rains it down on the forest floor and then the next ant can come along and pick it up in their cuticles. And that's how it completes the cycle.

• 16:47Kelly Weinersmith?

  Dantiel, the she ant does pick up.

• 16:50Daniel Whiteson?

  Dantiel, yeah.

• 16:51Kelly Weinersmith?

  Dantiel, that's right. Picks up the fungus and the cycle starts again.

• 16:54Daniel Whiteson?

  Wow. All right. Okay. And so the name of this fungus is some crazy Latin phrase.

• 16:58Kelly Weinersmith?

  Yeah. So Ophiocordyceps unilateralis. The unilateralis refers to the fact that the stalk comes out of one side of the ant's head. And so Ophiocordyceps is a genus. So there's a lot of different fungus species that are very closely related and they infect different ant species. So they seem to specialize on different species. So there's actually a bunch of ants all over the world that are infected by this fungus in slightly different ways. So the story isn't the same for all of them. The story I gave you is a story that I'd initially read for Ophiocordyceps unilateralis infecting an ant species in the tropics. But yeah, there's a lot of this happening in our world.

• 17:37Daniel Whiteson?

  And within this species of ant and this species of fungus, you're saying there's not a lot of variation in the behavior of ants. They like basically all do the same march to death and then brain explosion?

• 17:47Kelly Weinersmith?

  Brain explosion.

• 17:49Daniel Whiteson?

  Or, you know, fungal stalk extrusion or whatever.

• 17:51Kelly Weinersmith?

  Yeah. So we are going to talk about how they differ a little bit. The details can differ depending on where you are. But the story is generally the same, that they find a way to be up above the areas where the foragers usually go so that they can rain the spores back down again.

• 18:06Daniel Whiteson?

  Wow. Amazing. So tell us how it works.

• 18:09Kelly Weinersmith?

  So first I want to note, we call these zombie ants. And I often get people in the field grumpy with me for calling them zombies because they're like, people are going to think they come back from the dead. Dear listener, I don't think that you think that ants come back from the dead. But just to be clear, the zombie ants do not come back from the dead. They are, their behavior is getting hijacked while they're alive and then they die in a very particular position that benefits the fungus.

• 18:34Daniel Whiteson?

  So you're saying they're not zombies because the ants haven't died. They're just in some sort of like controlled state where they're not really acting the way they would if they were normal ants. They're like drunk or they're hallucinating or something.

• 18:47Kelly Weinersmith?

  Something like that. And yeah, it looks like their circadian rhythms are getting messed with. So Charissa De Becker's lab has looked at how a big part of the manipulation seems to be them doing kind of normal behaviors, but at abnormal times.

• 19:00Daniel Whiteson?

  So that seems to me a very technical definition of zombie. I mean, if humans, for example, were infected by something which made them stagger around and want to eat brains, but weren't technically dead, would you be there being like, excuse me, you're not a zombie, sir?

• 19:14Kelly Weinersmith?

  No, because I, I love fiction in all of its forms. And as long as the rules are consistent in the world that's created, I don't care. So when I use the word zombie, I basically just mean an organism where a significant amount of its behaviors seem to be under the control of another critter. And those behaviors are good for the parasite, but usually bad for the host.

• 19:36Daniel Whiteson?

  All right, well, let's take a break because I definitely need one and come back and hear all about the details of how this fungus controls this ant.

• 19:55Speaker 00

  Hey, it's Nile Rodgers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything. This week, I'm joined by breakout singer-songwriter Alex Warren.

• 20:15Speaker 14

  To this day, Ordinary would not have done anything and I would have not been able to put it out if, if Book Talk didn't back it up and if my wife and her friend didn't back it up.

• 20:23Speaker 00

  Amazing.

• 20:24Speaker 14

  Pretty crazy how like. Just one thing.

• 20:26Speaker 00

  Right.

• 20:27Speaker 14

  I mean, you, I bet you, we could point to nine different things in our careers where it's just one thing, all of a sudden, if that one thing didn't happen, then I wouldn't be here.

• 20:34Speaker 00

  What you're talking about right now

• 20:36Speaker 14

  Yeah.

• 20:36Speaker 00

  is what I've been talking about since the beginning of my career. There's these things outside of you

• 20:41Speaker 14

  Yeah.

• 20:42Speaker 00

  that make everything happen. These other forces somehow came into contact with each other

• 20:49Speaker 14

  Yeah.

• 20:50Speaker 00

  and helped propel you to this place.

• 20:51Speaker 14

  It's just insane.

• 20:52Speaker 00

  Experience before the moment. A Lincoln original series on the iHeart Radio app, YouTube, or wherever you get your podcasts.

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• 23:43Daniel Whiteson?

  OK, we're back. And we're talking about the name of a fungus that I cannot pronounce, but is amazingly adept at manipulating ants.

• 23:50Kelly Weinersmith?

  This is a really nice, like, turn of the tables. Usually, I'm the one who can't pronounce things. We've got to do more, more episodes with, like, complex Latinate names. But, OK. So, one of the first things I think is so amazing about this system is that it evades the social immune system that ants have. So ants are very genetically related to one another. And they work together for this common goal of, like, helping the queen create more offspring and stuff like that.

• 24:18Daniel Whiteson?

  And they have complex fractional relationships, right? It's not just like you have kids that are half you. You're, like, related by a quarter, or a sixth, or a third, or something complicated, right?

• 24:27Kelly Weinersmith?

  I think it's like three-quarters. Like, you're way more closely related than, like, you know, my brother and I would be, for example, typical siblings. And so they're, like, you know, pretty close to you genetically. And so this tends to result in what look like altruistic behaviors. And so if one of the ants comes into the colony and is clearly infected with something... The nest has a like social immune response where other nestmates will be like, "Oh, you can't bring that in here, man." And they will, in some cases, kill that ant and then go put it in like a graveyard somewhere far away from the nest so that it can't infect the rest of the nest.

• 25:04Daniel Whiteson?

  Based just on the behavior, it's not like it's giving off some pheromones or something.

• 25:08Kelly Weinersmith?

  I think in a lot of cases, we don't know exactly how the nestmates can tell. It's probably some combination of behaviors and then ants are a species that in particular tends to communicate a lot with chemical cues. So it could be that they sort of smell or whatever, taste a nestmate and they're like, "No, that's, that's weird. We're kicking you out."

• 25:26Daniel Whiteson?

  Daniel, you taste funny. We're killing you.

• 25:28Kelly Weinersmith?

  Yeah, that's right. That's right. Daniel, it's not how your forehead is supposed to taste. And I licked it and now you can't live here anymore. Danchel, danchel. And so anyway, so usually when an infected nestmate comes back, it gets picked up on and they get killed and kicked out.

• 25:44Daniel Whiteson?

  Brutal but fair.

• 25:45Kelly Weinersmith?

  Brutal but fair. And this is a pathogen that you would want to put a stop to. So, you know, if they don't capture this individual and kill it, it is going to create essentially like a stock of infectious propagules nearby. So anyway, there should be selective pressure for this.

• 26:01Daniel Whiteson?

  And so how does it evade this selective pressure? Why can't the other ants tell?

• 26:05Kelly Weinersmith?

  So we don't have a great handle on why the other ants can't tell. Part of it seems to be that in at least some systems. So I'm going to be talking about this system like every system acts the same way, but just sort of like with the tardigrades, some questions have been asked in one Ophiocordyceps species infecting one ant species, some questions have been asked in other systems, but we're going to mix and match for the purpose of this show. But there's the disclaimer. So some ants, the timing of their behavior changes and they interact with nestmates less often. And so part of the story might be that instead of just like blindly going into the nest and then getting found out, these ants that are infected are avoiding nestmates. So they never get found out. They never get their forehead licked. And so, uh, so they're able to escape in that way.

• 26:49Kelly Weinersmith?

  It could also be like the scent of the fungus is being masked in some way, but through mechanisms we don't understand, it manages to evade the social immunity of the nest.

• 26:58Daniel Whiteson?

  Wow. Amazing.

• 27:00Kelly Weinersmith?

  Yeah, pretty cool. All right. So now you've got this ant that's infected. Its nestmates haven't killed it like they probably should have. And then at some point, it does that drunkard's walk. And we don't really understand why that drunkard's walk happens. But there is a chemical that's produced by the ant that is associated with something that causes like staggering and seizures in other insects. And so we think that it's going out there and it's starting to do this staggering thing because of some chemicals produced by the fungus. It gets down to the forest floor. And now the interesting question is, how does it know where to go? So this is the summit disease part. It starts climbing up. But we're trying to figure out, how does it know where to stop? How does it know where a good spot is?

• 27:43Daniel Whiteson?

  Well, it's very confusing to me that the behavior is so complex that it includes climbing down and then climbing up. Like, I could see it somehow is pulling on some lever inside the brain to make it go up or to make it go down. But to make it go down and then up, like, that's really amazing.

• 28:00Kelly Weinersmith?

  That is really amazing. I mean, I think part of the selection pressure there, and this is just me telling a story. I haven't, we don't, I don't know that we've tested this. But if the ant had gone down, it's probably, one, going down a big trunk. And they tend to attach to like thin stems, and we'll get into that in a second. But also, if it just kind of clung in an area where foraging ants would be going up and down anyway. If a foraging ant sees a dead ant with a stalk coming out of its neck, that it is going to throw over into the trash can. And so that would be the end for the fungus, too.

• 28:32Daniel Whiteson?

  So that tells us why that strategy, the simpler strategy, wouldn't work. It just like clinging to the tree. But it leaves us still impressed with this complex strategy of climbing down and then climbing up.

• 28:42Kelly Weinersmith?

  Right. And so let me go ahead and jump ahead a little bit to the benefit of climbing back up again. So there's been an experiment done where they took ants that had like settled in at a particular location. And they cut the leaf off that the ant was on, and they moved it up. And when you move it up, The temperature and the humidity are no longer good for the fungus and the fungus can't make that stalk and it can't make the infectious propagules that rain down on the other foragers. And so there is this like kind of narrow band that the fungus needs to be in in order to complete its development. And so, you know, it takes some work to find exactly the right spot.

• 29:19Daniel Whiteson?

  And it's fascinating to me to imagine all the evolutionary dead ends, you know, ants that just went down and never climbed up, ants that climbed up the tree instead and didn't propagate. It's incredible that this whole thing came together.

• 29:31Kelly Weinersmith?

  Yeah, yeah, it really is. Well, and I'm sure that a lot of times when like researchers go out to study this kind of stuff, like, you know, if you're too low, then spiders and other scavengers come along and they'll eat the zombie ants. And so there's probably some instances where the ant dies in the wrong spot, but the researchers never find it because something has eaten it and it's gone. So, you know, you do the best you can with the data you've got.

• 29:55Daniel Whiteson?

  So tell us about this climbing up. How does it know where to stop? That it gets this right height? Like, do we understand the mechanisms for how it knows how high it is? It's not like doing GPS or something?

• 30:06Kelly Weinersmith?

  So we think it's queuing in on light, which is amazing to me because it's inside the body of an ant. And so how is it getting information about light? So what they did was they found what's called ant graveyards. So the ants tend to accumulate in certain areas of the forest. And so they're like, okay, we know this is an area that's good because the fungus have chosen to be here before. And then they put a little bit of a light shade over the zombie graveyard. And so now that area is getting a little bit less light than it was getting before. And what they found was that if you go back in future weeks, that area doesn't get as many new ants as nearby areas that have more light. So it looks like the fungus is driving the ants towards areas that have certain amounts of light.

• 30:50Kelly Weinersmith?

  And then they looked, there were still some newly infected ants that went into the areas with the shades. And if you followed what was happening with that fungus over time, the fungus was less able to produce those stalks and produce, I'm just going to call them baby fungus because no one wants to hear me try to say propagule again. So less baby fungus gets made in areas where you've got these shades.

• 31:12Daniel Whiteson?

  I see. And so the ants are using the light as a cue for where to go. Is the light important in making the baby funguses? Or is it just like a signal to the fungus of when the ant has crawled up to the right height?

• 31:24Kelly Weinersmith?

  I think that the light is used as a proxy for information about temperature and humidity. And it could be that the light is important for some way, too. I don't know, fungus, I don't know. But nature's complicated. But it does look like things like temperature and humidity and light are all important for the way the fungus is able to develop.

• 31:42Daniel Whiteson?

  Wow, fascinating.

• 31:43Kelly Weinersmith?

  And this is the part that you see in other insects, too. I talked about those zombie flies and those caterpillars. This climbing up thing happens in a lot of insect systems.

• 31:53Daniel Whiteson?

  And then you said they also bite down. They like clamp on to this plant. Why is that part important? Is it because the ant's gonna die and you want it to stay there?

• 32:00Kelly Weinersmith?

  Yeah, so you want the ant to stay put. And so in the tropics, what happens is they find a leaf. They crawl along the bottom of the leaf, along the major leaf veins. And the ants will clamp down with their mandibles. They've got these pincers. And their muscles will like hypercontract. So they'll like really strongly bite down. And then the ants will never be able to open their mandibles again, and they will die there.

• 32:24Daniel Whiteson?

  Wow.

• 32:25Kelly Weinersmith?

  And so that's how they hold on.

• 32:26Daniel Whiteson?

  Incredible.

• 32:27Kelly Weinersmith?

  And this is called the death grip. And one of the things that's interesting is that depending on where you are in the world, the death grip will look a little bit different. So in the tropics, they tend to bite down on leaves. But if you go to like North Carolina, for example, instead of biting down on leaves, they'll bite down on stems. And they'll also wrap their legs around them. And so they'll hold on with their legs and with their pincy parts. And we think that the reason that they hang out on stems instead of leaves in areas that are farther north, like North Carolina, is because in the tropics, leaves really never fall off the trees. Or they at least don't have a seasonal pattern of falling off in the winter. Whereas farther north, if you bite down on a leaf,

• 33:12Kelly Weinersmith?

  you've got until like, I don't know, August, September, or October before those leaves start to fall off. But if you're on the stem, then you can stay up there for longer raining fire down upon the other ants. And so it looks like there have been four different instances where you've gotten this evolutionary transition from biting down on leaves to biting down on things like stems.

• 33:33Daniel Whiteson?

  This is fascinating. I love these moments in science when you can look at what's going on and unravel it and tell a story. I remember Hazel summarizing all of science once. She says like, "Stuff happened and we figured out why." And I'm like, "Yeah, that's pretty much the whole idea."

• 33:51Kelly Weinersmith?

  Yep.

• 33:51Daniel Whiteson?

  So by looking at this pattern of how things evolve differently in different parts of the world where the conditions are slightly different, we start to get a sense for how this all came together. That's incredible.

• 34:01Kelly Weinersmith?

  Yeah, it's really incredible. And I got to see one in North Carolina. I'll put a picture on this online when it comes out, but we found one in North Carolina and Andrew Turner found it. I was out looking for snakes and salamanders and Andrew Turner, a friend of mine, was like, is that a zombie ant? And I freaked out. Anyone in like a one mile radius probably heard me scream because I didn't think I was going to get to see a zombie ant. So anyway, I've seen them in North Carolina and then Andrew Turner put one in like a resin for me. And so I've got it on my desk and it is my favorite.

• 34:33Daniel Whiteson?

  And what are we looking at?

• 34:34Kelly Weinersmith?

  We are looking at, this is a bit of stem and on the bottom, there's an ant that's got its legs wrapped around the stem. It's biting down with its mandibles. You can see it's got a big stalk coming out of the side of its head. The spore that the fungus would come out of is kind of small. It's hard to see, but it's about maybe three quarters of the way up the stem.

• 34:54Daniel Whiteson?

  Wow.

• 34:55Kelly Weinersmith?

  Best thing I own.

• 34:56Daniel Whiteson?

  Best thing. You have children too, don't forget.

• 34:59Kelly Weinersmith?

  I don't own them, you know, I, they could choose to leave at one point, but this will never leave.

• 35:06Daniel Whiteson?

  It's a special place in your heart.

• 35:11Kelly Weinersmith?

  It is.

• 35:11Daniel Whiteson?

  All right.

• 35:12Kelly Weinersmith?

  So the ant bites down. And one of the cool things about this, what we call a death grip, is that it leaves a very distinctive mark. So if you find leaves, you'll see that they've got, it almost looks like, you know, like scissors cut on either side of the veins. And there are 48 million year old leaf fossils from Germany that have these little scissor cuts in them. And we think that these are like essentially fossil records of behavior showing that like around the time, a bunch of the different mammalian species were sort of evolving into existence, this manipulation was already happening. And you know, you can't be 100% sure the ants weren't still attached or anything like that. But it's indirect evidence that this is sort of an ancient association and a manipulation that's

• 35:57Kelly Weinersmith?

  been going on for longer than humans have been on this planet.

• 36:01Daniel Whiteson?

  And so when the ant mandibles do this hyper contraction, they make a special sort of pattern that they can't otherwise make because it's just the ant mandible, right? It's not like, how is this pattern different from a normal ant chomp?

• 36:12Kelly Weinersmith?

  So first of all, a lot of ants don't chomp around leaf veins like this. So you might be thinking about leaf cutter ants. And leaf cutter ants will cut out like chunks of leaves and bring them back to their nests so that they can, they feed them to fungus and it's sort of like a farming situation. But anyway, ants don't usually just go and like chomp down on leaves around the veins and then do nothing else with it.

• 36:37Daniel Whiteson?

  I see. So it's also the location of the chomp?

• 36:39Kelly Weinersmith?

  Yeah, it's also the location of the chomp.

• 36:41Daniel Whiteson?

  Wow, amazing.

• 36:42Kelly Weinersmith?

  Yeah, pretty cool. And so you tend to get aggregations in these good parts of the forest where the conditions are good for fungal growth. And so you end up with these ant graveyards where you've got a bunch of these zombified ants hanging on the underside of stems or leaves raining fungal spores down on their nestmates below.

• 37:00Daniel Whiteson?

  And does the fungus actually kill the ant? Or does this sort of death march end up exhausting the ant? Or why does the ant die?

• 37:08Kelly Weinersmith?

  I don't know if the ant dies because once it bites down, it can't use its mandibles again. I don't know if it just eventually dies because it runs out of energy or if the fungus kills it. But I do know that pretty soon after it bites down, the fungus starts consuming the inside of the ant to make more fungal tissue instead.

• 37:25Daniel Whiteson?

  And how long is it like spraying propagules for?

• 37:28Kelly Weinersmith?

  That really depends on where you are. I think in some parts of the world, it happens for like just a couple of months. I think in some areas, I think it can happen for like a year. That really depends on the environment that you're in.

• 37:40Daniel Whiteson?

  All right, and let's take a break. And when we come back, we'll hear about how this benefits the fungus and how the ant manages to pull this all off.

• 37:57Speaker 00

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• 41:45Daniel Whiteson?

  OK, we're back and we're talking about the death march of zombie ants. Kelly, tell us why the fungus makes this happen? Why can't the fungus just find some other friendlier way to spread itself?

• 41:58Kelly Weinersmith?

  I don't know why it doesn't find a friendlier way to do it. But we do know that this method seems to work for the fungus. As we sort of hinted at earlier, it's actually pretty easy to move these ants to different places to test out, like, where would the best place be for these ants to have settled down? So you can cut off a leaf, and if you move it up too high, as we mentioned earlier, the temperature and humidity and lighting conditions are just not good. And the fungus will essentially never be able to produce that stalk that makes the spores. And so that's the end of the line for the fungus. Not great. And if you move it down too low, it gets found by scavengers. And so unlike a lot of other examples where we have a nice story, here we've been able to manipulate the system a little bit and say, you know, look, if you do something different than what we're seeing,

• 42:41Kelly Weinersmith?

  the fungus is quite clearly doing less well. The fungus either gets eaten. And killed, or it can't make babies.

• 42:47Daniel Whiteson?

  I'm still sort of amazed that this whole thing works. Like, I can imagine a fungus infecting an ant and it makes a small change in the ant's behavior. And maybe that benefits it a little bit. But this benefit requires such complex behavior for the ant to go down and then across and then up and then bite and all this stuff. All these pieces have to basically fall into place due to random mutation. So how do you get all the way to this complex behavior when none of the individual pieces on their own are going to benefit the fungus?

• 43:14Kelly Weinersmith?

  Yeah, that's a great question. So one thing that's worth noting is that, you know, as we've mentioned earlier, this summiting disease thing happens pretty often. So it suggests that there's something about insects where it's not too hard to manipulate their ability to go up or stay up. And so a number of different kinds of parasites and pathogens have found the switch. I can't say I'm an expert on what that switch is, but there's a couple of different routes to up and stay there. But you can imagine that this happened, you know, step by step. So maybe the first thing that happened was that ants that were starting to show signs of being infected by the fungus left the nest so that the nestmates didn't kill them. And maybe they died on the forest floor. And then there happens to be an ant that climbed up a little bit before it died.

• 43:58Kelly Weinersmith?

  And that helped the fungus relative to just dying on the floor. And so you can, you know, imagine how each step could have happened first and then been honed over time. But this is definitely one of those things where we have to tell a story and we can't be exactly sure what happened in what order. I mean, maybe what happened first is that the ants that are infected by a fungus would die high up and they'd never go back to their nest. And maybe the nest stuff came later by some ant that happened to wander back, but wasn't discovered for whatever reason. And so, you know, each step, there's selective pressure for whatever benefits the fungus more. But the exact path that this took, I think the best we can do is speculate.

• 44:36Daniel Whiteson?

  I see, but it's plausible to string these complex behaviors together because each individual one already does benefit the fungus. So that, yeah, that makes sense. I wonder what in 100 million years this fungus will have these ants doing like, oh, it turns out if they do the Macarena before they bite down.

• 44:55Kelly Weinersmith?

  Yeah, yeah, it could be. I mean, I would imagine that like as climate is changing across the planet, the exact location where biting down is the most beneficial might change. And so there might be selection to like tinker with exactly where the ants end up. So you keep getting the right temperature and humidity. And maybe that will be like, you know, you should go to areas with even less light because everything is getting too warm and too hot. And so less light will be a little cooler and the temperatures will be right. Anyway, so I can imagine that happening. But part of understanding the steps is probably understanding the mechanisms because that gives you some insights.

• 45:28Daniel Whiteson?

  Yeah, like what's going on inside the ant that lets the fungus? What are these levers that the fungus is pushing?

• 45:35Kelly Weinersmith?

  Yeah. So first, let me just talk briefly about how we start answering these questions. So as we've discussed, there's a bunch of different steps here that the fungus is doing. And so the answer for how does the fungus manipulate behavior probably differs depending on what step you're talking about.

• 45:51Daniel Whiteson?

  Different ants, different answer.

• 45:57Kelly Weinersmith?

  Do I tell you often enough how much I like working with you, Daniel? Because I really do.

• 46:02Daniel Whiteson?

  I'm just going for the easy puns because somebody has to.

• 46:04Kelly Weinersmith?

  I know. The dad jokes, the amazing dad jokes. So the way that, you know, for example, if you're trying to figure out what differs between an ant that gets ignored by its nestmates and an ant that gets dumped, well, you can, for example, infect some ants with Ophiocordyceps and other ants with a different kind of fungus and send them both into a nest and see how they interact differently with their nestmates, how the nestmates interact differently with them. And then you can look at the different chemical profiles and say, like, this one is emitting these chemicals and this one is emitting these chemicals. And then try to figure out, you know, is the fungus, is Ophiocordyceps producing some chemicals that the other fungus doesn't produce? And then start looking into those as candidates for what's happening there.

• 46:50Daniel Whiteson?

  Do you need an IRB for these kinds of experiments? Or can we just experiment willingly on ants? Do ants have any rights?

• 46:56Kelly Weinersmith?

  That's a good question. So IRBs are almost exclusively for humans. So you don't need an IRB.

• 47:01Daniel Whiteson?

  But you can't just experiment on dogs and chimps and rats, right? There's some ethics there.

• 47:05Kelly Weinersmith?

  Yep, for dogs and chimps and rats, you need an institutional animal care and use committee protocol. And you have to jump through many hoops to make that happen, which, which we'll talk about on another episode. But for invertebrates like ants, you don't need to do those kinds of protocols.

• 47:20Daniel Whiteson?

  Wow.

• 47:20Kelly Weinersmith?

  But I will say that everyone who I've ever talked to who works with animals, even just little ants, gets pretty emotionally attached to them. And they do worry about like, how do I euthanize this ant to get my data in the way that will like, make it fastest? And, you know, I don't think we really know if ants feel pain or not, but like, if they do, how could we do it so that they'll feel the least amount of pain?

• 47:43Daniel Whiteson?

  So nobody's just callously grinding up ants. They're like shedding a tear while grinding up ants. That's nice.

• 47:48Kelly Weinersmith?

  Yeah. Let's move on.

• 47:51Daniel Whiteson?

  All right. No, but I mean, jokes aside, you're saying that scientists involved understand the costs here in terms of lives and experiences, even of the little ants. And that's nice.

• 48:03Kelly Weinersmith?

  Yes. No, they do. And, and I think they try to make the ants' lives as natural and as nice as possible before these experiments happen. But so mostly, the point I wanted to make was how, how we do these different comparisons to get a handle on what might be happening. And the answer is, you know, at very similar time points, you look at ants that are uninfected, ants that are infected by Ophiocordyceps, and ants that are infected by other fungus that are bad for the ant, but we don't think they manipulate behavior in any way. And by looking to see what's happening differently in the bodies and the behavior of the ants in those three different categories, we can start getting some like candidate molecules for, you know, this might be the thing that's getting produced by the fungus to change the behavior.

• 48:44Kelly Weinersmith?

  And so they found a lot of stuff that differs. And that's not too surprising because the ants are doing complicated behaviors, there's a lot of behaviors. I feel like what we really want as humans is that the answer is there's this one molecule, and that tells you everything. And, and that's fascinating. But really, it ends up being like hundreds of molecules that are being produced that we think are important in every single different step. So there's not like a really nice, easy to tell story. But a couple of things that pop out is that enterotoxins seem like they're important. These are toxins that are released by things like bacteria like E. coli. We're not totally sure what the toxin is doing to the ants, but it might be playing a role in breaking down ant muscles at particular times.

• 49:29Kelly Weinersmith?

  So maybe after the ant bites down, those muscles get broken down so the ant can't leave. And that might be what the toxin is doing when it's released at that point.

• 49:38Daniel Whiteson?

  I think it's great to try to dig into the details and understand the mechanisms to make sure the story that we're telling is the real story. And also because you could discover surprising things when you dig into the details. But what else could we learn by doing this? Is there the possibility here of a surprise that we discover, oh, it's not actually working the way that we expected?

• 49:58Kelly Weinersmith?

  Yeah, so a lot of people think of these behavior manipulating parasites and pathogens as like evolutionary neuroscientists. So they've been interacting with their host for, you know, in this case, it looks like more than 48 million years. And through the process of natural selection, they've maybe happened upon solutions for changing the ants' behavior. And so by looking to see what is the fungus making? If it's a compound we've never seen before, maybe we've unlocked some tiny piece of the puzzle for how brains work and how you can modify behavior. And, you know, you could imagine, maybe if you've got some pest in a field, if you make them all like, you know, climb up and stay up and then die, they'll like stop messing with your field. And so like whenever we can understand even how insect behavior works,

• 50:42Kelly Weinersmith?

  it gives you some extra tools to not just, you know, understand how your world works, but also to maybe sort of control some of the negative aspects of like pest organisms.

• 50:50Daniel Whiteson?

  Wow, so the fungus has been doing neuroscience experiments on the ants for 48 million years without ever writing a paper and getting their PhD. That's got to set some kind of record.

• 51:00Kelly Weinersmith?

  They don't have to worry about tenure. They don't have to get grants. They don't have to write permits and protocols. It really seems unfair, the head start that they've gotten. But if we study them, then we can sort of extract their secrets. And maybe this will help us like jump ahead in our, you know, study of neuroscience.

• 51:16Kelly Weinersmith?

  Which I think is a cool idea. And so they also found what they call a bioactive compound where they've, they've never sort of seen this before, but it looks like another compound that, as we talked about earlier, causes insects to stagger. And so this might explain why they sort of like walk down the tree like they're drunk. But we think, and this is, this is just hypothesizing at this point, we think it might be important in those systems where the ants are clinging to the bottom of stems. If the ants are feeling like all sort of wobbly and uneven, they might hug down on the, the stem to hold themselves so they don't fall off of it. And that could be sort of the moment that the fungus kills them so that they will be really clinging hard to the stem. And at this point, this is just a story and we know that we need to dig into it more, but that's where we

• 52:00Kelly Weinersmith?

  are right now. So it's complicated.

• 52:02Daniel Whiteson?

  And do we know like where in the ant the fungus ends up? Like, does the ant have a little ant brain and the fungus is sitting on top of it, like cackling maniacally and pulling levers?

• 52:12Kelly Weinersmith?

  Yeah. So this is really neat. So I, you know, I've already mentioned that Theresa De Becker's lab has been doing some important work on like timing and they've been working on like chemicals that are produced by the fungus. David Hughes did some work with collaborators where they scanned ants with an electron microscope. So like very, very detailed scans and they put all of the scans together. And what they found was that the fungus is forming a network and it's invading a bunch of different muscles. And so the way it was described in the popular press was that you could think of it as like the fungus essentially having strings on a puppet where it could be like pulling up and down. And I, that might be overselling it a little bit. But one of the things that they thought was interesting was that it doesn't

• 52:54Kelly Weinersmith?

  seem to be invading the brain tissue. So it's touching the brain, but not going into the brain tissue. This was made a pretty big deal in the pop sci articles at the time. I wasn't as impressed with that. So like the brain infecting parasite that I studied on fish for my PhD also sat on top of the brain and not inside of it. And there's some other evidence in the zombie ant system that the fungus is kind of protecting the brain. So you can imagine that like, if you're inside of the brain, you might just like totally screw up your ride. Like you're, it's not going to do what you want because you've just totally debilitated it. And now it's obvious and the other ants can tell. And so it looks like it's sort of tinkering with the brain without actually like sticking its

• 53:35Kelly Weinersmith?

  hands in there. But it does have its, you know, hypha, which are like fungal fingers inside the other muscles.

• 53:43Daniel Whiteson?

  Wow, amazing. And I see something amazing here in the outline. Tell me about hyper parasites. Are these like the superhero version of parasites?

• 53:51Kelly Weinersmith?

  Kind of.

• 53:52Daniel Whiteson?

  Were they bitten by a radioactive spider?

• 53:54Kelly Weinersmith?

  No, no, no, no, no. You've watched too many movies, Daniel.

• 53:58Daniel Whiteson?

  This is true.

• 53:59Kelly Weinersmith?

  Yeah, but just as cool. So, you know, you've got this fungus that manipulates ant behavior, but there are other fungal species that infect ophiocordyceps. So the ant will be like, you know, clinging to a stem and you'll find fungus that is living on top of ophiocordyceps and is sapping the ophiocordyceps' energy.

• 54:19Daniel Whiteson?

  It's like fungus inception. Wait, fungus antception.

• 54:23Kelly Weinersmith?

  Whoa, dad jokes galore. This might be our most dad jokey episode yet. I didn't see it coming.

• 54:30Daniel Whiteson?

  Wow. So this fungus thought it was pulling the strings, but its strings were being pulled the whole time.

• 54:35Kelly Weinersmith?

  There are so many levels in nature. I am so glad to be where I am. So, okay. So I promised at the beginning of the episode that I would answer if ophiocordyceps could jump to humans and manipulate us. Daniel, so now I'm going to ask you, what is your favorite representation of a fungus that jumps to humans? And you could just say, I don't watch the same shows as you do, Kelly.

• 55:00Daniel Whiteson?

  I'm not a fan of the zombie genre in general, the violence and the goo and like, ugh, not a fan. So yeah, I'm going to have to leave it to you.

• 55:09Kelly Weinersmith?

  All right. Well, okay. I've been really liking The Last of Us lately, but not necessarily because it like hews so closely to what happens in nature. So that one starts by saying like, yes, I know it seems unlikely that, I think they call it cordyceps. The genus name has changed a little bit, but anyway, I, yes, it seems unlikely that it could jump to humans, but the way our environment is changing, we can't rule it out or something like that. And then fast forward decades and humans are infected by the fungus. I think it is highly unlikely.

• 55:40Daniel Whiteson?

  Why is that?

• 55:41Kelly Weinersmith?

  Well, okay, so even in nature, we talked about at the beginning of the show that each Ophiocordyceps species tends to infect and manipulate specific ant species. So they are so specialized that they can't even like manipulate closely related ants. Like, that's too much of a jump.

• 55:58Daniel Whiteson?

  So maybe like if you know how to fly a Cessna, that doesn't mean that if somebody drops you into like a 747, you're gonna know how to land that thing.

• 56:07Kelly Weinersmith?

  Yes, exactly. Right? And human brains are so incredibly different than ant brains. I suppose it's possible that a fungus might be able to eke out an existence in us, but I even think that would be quite a jump. But if it could, the probability that it would be able to control our behavior in a way that would benefit the fungus seems pretty close to zero. And I'm not being negative about the movies and TV shows and books that are great and Daniel's missing out. I think it's great that they created these worlds and if they're consistent with their rules, I'm on board. But I'm a person with massive anxiety and it doesn't keep me up at night worrying that Ophiocordyceps is gonna jump to me or my kids.

• 56:48Daniel Whiteson?

  Well, I have a theory for how this fungus can jump to humans and benefit itself.

• 56:52Kelly Weinersmith?

  Okay.

• 56:53Daniel Whiteson?

  If you think of this fungus as little neuroscientist, then what should it do? It should get humans to help it out. So if it infects human brains and makes those humans interested in this ant puzzle, so they come along basically acting like colleagues and figuring out like, hey, how does this actually work? And maybe it can help like, you know, super engineer this fungus to be even more efficient.

• 57:14Kelly Weinersmith?

  I feel like you're in a roundabout way trying to get back to the like, it's okay that I eat cookies at night thing. Like, you know, if the fungus benefits from me eating cookies. But you know what is interesting? So Ophiocordyceps sinensis infects, I think it's caterpillars, but infects critters. But instead of having them climb up, it has them burrow into the ground and then the fungal stalk grows out of the ground and like pops up. And humans have decided that this is amazing in tea. And so people will actually go out in search of this and they can sell it for a lot of money. And, and you can, I think you can even buy this in the United States, like tea with Ophiocordyceps Sinensis in it.

• 57:56Kelly Weinersmith?

  And so, you know, I don't, maybe Ophiocordyceps Sinensis jumps to us and makes us want the tea. And so then we'll start big farms where we sort of seed their, their hosts with the fungus so that they can start growing up and then we can, can replicate it. So maybe that'll be the route.

• 58:12Daniel Whiteson?

  Or maybe that'll just be the story in your Netflix show. Netflix, call us, we're ready.

• 58:18Kelly Weinersmith?

  Yeah, you know, I wrote fiction once and I kind of think it was a disaster. So I don't see me starting a new fictional series, but if anybody would like a scientific input on their own series, I am available.

• 58:34Daniel Whiteson?

  And she promises not to be completely a wet blanket.

• 58:37Kelly Weinersmith?

  And I, you know, I don't like to make promises I can't keep.

• 58:43Kelly Weinersmith?

  I'll try to play along. All right. So just to sort of reiterate, I love this system because I, we've dug into more of the different pieces in this system than a bunch of other systems, but there's so much we have left to learn. And as we mentioned earlier, like we're discovering molecules that we've never seen before. This might be a way to help us understand how brains work and how we can sort of tinker with behavior. It might give us some inputs on how to like control insect populations. There's so much cool stuff we might have left to learn as we continue digging into this system.

• 59:12Daniel Whiteson?

  Amazing. And it's incredible what we can learn from like ants and fungus. And sometimes that tells us something deeper about the way brains work. And so you never know where the next great scientific discovery will come from and who's really pulling your strings.

• 59:27Kelly Weinersmith?

  That's right. But the next great scientific discovery is probably coming from biology. That's what I think.

• 59:34Daniel Whiteson?

  As long as it gets into people's heads and makes them listen to the podcast, I'm all for it.

• 59:38Kelly Weinersmith?

  Or gives Daniel an excuse for eating cookies in the middle of the night.

• 59:42Daniel Whiteson?

  Chomp, chomp, chomp.

• 59:51Kelly Weinersmith?

  Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We would love to hear from you.

• 59:57Daniel Whiteson?

  We really would. We want to know what questions you have about this extraordinary universe.

• 1:00:03Kelly Weinersmith?

  We want to know your thoughts on recent shows, suggestions for future shows. If you contact us, we will get back to you.

• 1:00:09Daniel Whiteson?

  We really mean it. We answer every message. Email us at [email protected].

• 1:00:16Kelly Weinersmith?

  Or you can find us on social media. We have accounts on X, Instagram, Blue Sky. And on all of those platforms, you can find us at D and K Universe.

• 1:00:25Daniel Whiteson?

  Don't be shy. Write to us.

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• 1:01:28Speaker 22

  What's that?

• 1:01:28Speaker 21

  My fresh detector.

• 1:01:30Speaker 22

  Uh, your what?

• 1:01:31Speaker 21

  There it is.

• 1:01:32Speaker 22

  What is it detecting?

• 1:01:34Speaker 21

  Fresh produce, fresh meat.

• 1:01:36Speaker 22

  Okay, what happens if it detects something really fresh?

• 1:01:42Speaker 21

  Apparently, we celebrate.

• 1:01:44Speaker 23

  At Food Lion, you can count on fresh food at fresher prices when your fresh detector is going off. Head to your local Food Lion or shop at foodlion.com. This is an iHeart Podcast. Guaranteed human.