Real Life Zombies: How Parasites and Fungi Control Animal Minds

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What if “zombies” weren’t just fiction?

In this Season 14 kickoff episode of Wildly Curious, Katy Reiss and Laura Fawks Lapole dive into the real science behind “nature zombies”—organisms that can hijack behavior, manipulate brains, and turn animals into living tools for their own survival.

From parasitic fungi to mind-altering parasites, this episode explores how evolution has produced some of the most disturbing—and fascinating—strategies in the natural world.

🧠 How parasitic fungi infect insects and control their behavior down to the exact moment of death 
 🐜 The infamous zombie ant fungus (Ophiocordyceps) that forces ants to climb and die in precise locations for spore release 
 🦗 How hairworms manipulate insects into seeking water—something they would normally avoid—just to complete their life cycle 
 🐭 The parasite Toxoplasma gondii, which alters fear responses in rodents and may even influence human behavior 
 🦟 Cicada infections that turn insects into walking, mating, spore-spreading machines

These aren’t just gross curiosities—they’re real examples of how parasites can alter nervous systems, change decision-making, and reshape behavior at a biological level.

Transcript

SPEAKER_00 0:00

Did it ask you for your permission?

SPEAKER_01 0:02

It asked me for consent.

SPEAKER_00 0:03

Yeah. Non consent. You consent. You consent to talking to me. Whoo. First, that's first out of the way. Laura consents to talk to me. Guys, it's season 14. This is we start every season of just disbelieving.

SPEAKER_01 0:19

But also this one, I feel like, you know, so while while we were gone from recording, we had our five-year anniversary in February. Freaking nuts.

SPEAKER_00 0:28

So nuts.

SPEAKER_01 0:29

That's the craziest part for me.

SPEAKER_00 0:30

Others, other random things that happened while we've been gone. Let's see here. We've we're now listened to in 135 countries. We still are only in 49 states because of North Dakota. I just looked again to call somebody. Call who you know. If anybody knows, I put something on threads multiple times. I'm like, we just need someone, one person in North Dakota. And then we have all the things. Yeah, right? Who's up? I would say who's close, but there's also nothing close up there anyway. So south. But yeah. Yeah, right. So anyway, so yeah, 135 countries. Man. Oh, yeah. So we have the sponsor follow that we're sponsors. If you guys, if you check out the link on the bio, I do a little promo audio thing. It's a tracking bracelet, so they donate 10% of their proceeds to some really awesome conservation organizations. Some of the biggest ones that Laura and I have actually worked with and partnered with whenever we were in Zoom. Yeah, tons of them. Save the Rhino, San Diego Zoo, Diane Fossey fund, some very, very major ones. So if you guys check and click on the link on the bio, you get it's 20% off off of the tracking bracelets. And it is really cool. It has an app, and so you can go on there and see. Luke and I have sharks, lions, gorilla, uh, whale shark. We have a lot of really cool ones. And then it gives you a little blurb about them, and then you can watch where they are. And it is, it is pretty, pretty darn neat. And I think it'd be such a good gift. It it really, it really, really is different. Jewelry and an animal. It's pretty cool. It's pretty cool. So yeah, check that out. What else?

SPEAKER_01 2:03

You're gonna do this Texas bird thing?

SPEAKER_00 2:05

Oh my goodness. Okay, listen, I don't get nervous about birding, but I'm actually so Texas, right?

SPEAKER_01 2:11

That's an absurd thing to be nervous about.

SPEAKER_00 2:13

I'm nervous. Okay, listen, listen. Okay, so Texas. We have like 634 plus species of birds within the state. One, I get it, Texas is huge, but we're also very diverse and we are the central flyway. Yeah, yeah. It all costs.

SPEAKER_01 2:26

You got some absurd amount coming through.

SPEAKER_00 2:28

Yes, anything from South America for the most part is like whoom, like right up. The ones who don't want to cross the Gulf or go up through Florida, through the swamps, they're like all up our way. So it is nuts spring migration. I was out last week and we hit kind of like a peak migration. It was it was un unreal, everything that I was hearing. McGee marsh level? Oh my, yeah, yeah, yeah. No, absolutely McGee Marsh. So if you guys don't know what McGee Marsh is, it's in Ohio. Laura and I went to it whenever we were in college. It's kind of like the last stopping point for birds before they have to fly over the Great Lakes to get to Canada. And so there's just birds. Yeah, and it's tons of birds, tons of people, photographers. It's nuts. But imagine that, but all over Texas. It's crazy, and tons of people travel to Texas. The birders traveled to Texas for spring migration. It's crazy. This is the 30th year. I knew it was a big milestone year. So this is the 30th year. The Great Texas birding classic has been going on. So there's different groups that you can do. You can either go by yourself, you can join a team. There's kids' divisions, and basically you just and there's the big sit competition that's all wrapped up into one.

SPEAKER_01 3:38

It's funny that you guys, it's like a straight-up sporting event. Of course it is.

SPEAKER_00 3:43

My gosh, it is. It's so freaking is.

SPEAKER_01 3:46

I love the nerd level we don't have that year. We have like City Nature Challenge and stuff like that. But this is like the Great Burden Classic.

SPEAKER_00 3:54

No, right? And of the teams, let me look here. I I don't know how many teams are actually in it this year, but there's 22 wait 22 pages of teams.

SPEAKER_01 4:06

You gotta tell everybody what your team name is.

SPEAKER_00 4:09

The cheeky warblers. A big owed salute to our one of our or one of our warblers that's endangered in central Texas.

SPEAKER_02 4:16

Warblers.

SPEAKER_00 4:17

Yeah. So I I don't, it's one of teammate came up with that name. So there's me, and then I have two other teammates who are great, other birders. Coincidentally, the so there are two other female birders. One of them I met whenever I was standing out looking for the burrowing owls that were here. And I was standing out there and somebody pulled up, and then she got out, and I like peeked because I was getting cold, and so I peeked my head out. I was like, Are you looking for the burrowing owl? And she's like, Yes. And then and then we just stood there, we were looking for the owl together. So As birders do. As birders do. And again, she's like like our age and stuff, and so whenever she got back, she reached out to me on Instagram and stuff, was like, hey, and then and then was later on, was like, hey, we want to do this team. So we're just we're doing a dispersed flock, regional, all right, because there's state level, there's like so dispersed flock, we each kind of go our own separate ways. So there's three of us and Luke, my son. Um, you have to be over 18, or you have to do the youth division. So he's like the on honoree, like a non-competitive one. So we are an we have a region. Let's see here. We are the prairies and piney woods west. All right, is our region because that's how many different areas are in Texas. It's nuts. So you spread we spread out again, disperse flock. So we spread out, and then it is literally like have you seen the the show, the old game show where somebody's running through what is it, the shopping one where they're like running through and just grabbing. Yeah, yeah, yeah. That's legit like what it is. It is birds, it is like as fast as you can. Disperse flock because you're pretty much individual. Most if you're going in groups, because the intact flock is like you go around together, but typically you're like, Yeah, but typically you're at like at a park or at somewhere all together. Disperse flock, it is on the honor system, but people take it serious, so it's like public shaming and shunning um if you're gonna cheat. And so you can't, you know, can't use bird calls, but you could you can uh pish as much as you want. All right, so it's like there's some some little caveats and some rules to it, but um, it's like eight wait, no, it's like 12 pages of rules for this thing. Yeah, so it it's but it's exciting, and so that's why I said it's I'm nervous, but it's 24 hours, right? So I and and and so it's because of the dispersed flock, it's from April 15th to May 15th. You pick your day within that window, right, for dispersed flock. So we could pick whatever 24-hour day we wanted to do it today, but it's it's rainy and all gloomy out. So we postpone it to tomorrow. We just have to weep you pick your day, you have to let uh Texas Game and Fish know 24 hours ahead of time. And so you let them know say, hey, this is the day we're doing it, this is the day we're going out, and then you just disperse out. We all keep track of all of our birds that we do, submit eBird, we all do one big group, eBird, and submit it all together. And then if you win, you're recognized at a huge conference that's I think down in San Antonio for this year. So um so cool. Yeah, so it is pretty a pretty big deal, but again, I mean, people come from all over the world uh during spring migration to Texas, so it is a huge deal. Um, I haven't been down to the Rio Grande Valley yet, but that has like that's a whole other ecosystem of birds.

SPEAKER_01 7:37

Um there's uh Mona birder that I know that was telling me about the there's like some specific kingfisher down there, I think that's only on the Rio Grande.

SPEAKER_00 7:47

Yes. There's you're like, oh, I know. Yeah, there's several species that are down there that are only in there's some owl, there's an out like a teeny tiny owl that's only down there.

SPEAKER_01 7:56

There's like a special crow.

SPEAKER_00 7:58

There's a ton of stuff that is just down there. So people think like Texas, and they automatically go to like tumbleweeds and cacti, and it's like, no, we have like prickly pears, but like you know, cacti cacti that you're picturing the huge ones, that's like Arizona, so that's further west. Texas.

SPEAKER_01 8:14

There's a prairie, a lot of prairie, and yeah, a lot of prairie.

SPEAKER_00 8:17

So we have it's very diverse, and so we have so many, again, 634 plus species that are recognized. And so, so yeah, it's it's really exciting. And then for Luke and I, this is coming off of we just got back a few couple weeks ago or so from our big booby adventure. Um, thank you to everybody.

SPEAKER_01 8:35

I feel like half the people who are listening are like, I didn't know she was listening to birding. Like, you know, maybe you guys have to like look up Katie's Wildly Katie, yeah. Wildly Katie. Like look up Katie's birding adventures on Wildly Katie.

SPEAKER_00 8:50

And what's funny is like when I get into these rants at work, everybody's like, and I'm like, listen, I do have other hobbies, I do other stuff outside of work because like I'm a mom too, but this is like, and thank God Luke really enjoys it now too. But this is my me thing. This is like my my mom time, and I and I love it.

SPEAKER_01 9:09

And so it's relaxing and exciting at the same time. It's a treasure hunt, but it's a hunt on a slow pace, exactly.

SPEAKER_00 9:16

And and so I love it. And so those go and look at my wildly at Wildly Katie on Instagram, and I we do po I do post them to um our YouTube page for the podcast as well. All the links are in the bio and stuff. Um, but we just we did a little bit of fundraising it, a lot of supporters, so appreciate everybody who donated to help us start Luke off on his adventure. He wanted to find all, he wanted to see all the boobies in the world, aka all seven different booby species. We were hoping for two whenever we went down to the Texas coast. We got one, the red-footed booby, and that was a lot of fun. I you want to talk about pressure because people donated and we weren't seeing it.

SPEAKER_01 9:54

Find a booby. Yeah.

SPEAKER_00 9:55

Yeah. I was pretty bummed after the first day and a half of not finding it. At that point, we had probably put like nine hours or so into looking for it and hadn't found it. I was stressing out, and then we then we ended up seeing it. So that was super exciting. So, yeah, through all this, thankfully, Luke really enjoys it and he really gets into it too. Because again, we're gonna get home from school, he's gonna get home from school tomorrow, get a little bit of sleep, and then it starts at midnight, and so we're gonna go, we're gonna go a little bit past midnight, and then up at two or three o'clock in the morning. We're gonna be out starting birding. So, yeah, so a lot of research has gone into it. I'm gonna be posting a bunch of videos about everything that goes into it. But yeah, it there's a lot. There's a lot of uh of prepping and planning that goes into make the most of your uh your 24 hours.

SPEAKER_01 10:41

So gosh, it sounds so exciting. I want to do it. I wish they had one in Maryland. I would totally do it. It's fun.

SPEAKER_00 10:46

You have to fly down then when you're gonna be. Yeah, like the breeding bird.

SPEAKER_01 10:49

We have breeding bird atlas and things like it's just not the same. It's not the same.

SPEAKER_00 10:52

Yeah, it's not like to the level of Texas. I'm telling you, man, every it's just Texas. You just take things bigger in Texas, yeah, yeah, for better or worse. So, well, this is gonna be take a drastic turn because today we're talking about nature's zombies. From birds to zombies.

SPEAKER_01 11:09

Yeah. If you have never listened to our podcast before, this is not actually not that atypical.

SPEAKER_00 11:14

Yeah, this is yeah, this is pretty, pretty common. Normally, Laura's the one that makes the jump and somehow of connection. I'm like, birds can be affected by some of these, like yeah, birds get par parasites.

SPEAKER_01 11:25

I don't know.

SPEAKER_00 11:25

Yeah. So we're gonna be talking about fungi and parasites and how they can take control of our host, creating a state of basically like living death.

SPEAKER_01 11:34

I'm so ready. Okay. So, okay, if I've said it once, I have said it a thousand times. Fungi are freaking awesome. They are really cool. I just molds, yeast, mushrooms, and more, they're all over our world filling every niche available. Some are beneficial and others aren't so much. And so I'm gonna talk about some of the scary ones that literally hijack a brain.

SPEAKER_00 11:57

This whole episode, I first of all, I'm so sorry, guys, that like we're kicking off with this episode. It's cool, but at the same time, it's like you know what I mean? It's like, yeah, yeah. Ugh.

SPEAKER_01 12:08

I I think at least mine are not able to do anything to people.

SPEAKER_00 12:13

I don't mine are. I audibly gagged multiple times. Continue.

SPEAKER_01 12:18

Yeah, yeah, yeah. Yeah, because the parasite one I know can affect some mammals. Anyway, so let's start off with some good news. Like I said, at this time, we are only aware of parasitic fungi that can hijack invertebrates. We just better pray it never jumps to mammals. So we are only talking about inverts with mine, typically because warmer bodies are just not good host to fungi. They need cool moist habitats. So, real quick, I'm gonna do like how does it work with fungi even like getting inside of something, and then I'm gonna go into like my two different examples. Okay. So fungi are spread through fungi spread through spores, like we've talked about in previous episodes, kind of like seeds. These little teeny tiny spores get stuck to an invertebrate an invertebrate, which is an animal without a backbone. And then that penetrates their hard outer skeleton. Um, once inside, they rapidly bud, which is when things just start like splitting apart and fill the host. Once the host is dead, they typically produce new spores to infect a new host. This can look different, but that's the whole point. It's to infect something to then spread itself and start the cycle again. So some of some of these parasitic fungi may have very specific hosts, like specific species and only that. Um, or some are more general.

SPEAKER_00 13:45

Yeah. But that's crazy from like an evolution perspective. You know what I mean? To be like, that they're actually that they're like one thing.

SPEAKER_01 13:52

That's my thing.

SPEAKER_00 13:54

Yeah.

SPEAKER_01 13:55

And usually in nature, that's such a detriment. Like, usually you should never be that niche because then you're like, you know, there's too many other pressures that can make you disappear, but apparently not for fungi. Yep. Okay. So not all of not all parasitic fungi, even hijack a host and change behavior. There are some just plain old parasitic fungi that just are like living on and in things. But we wanted to talk about zombies, so mind control. So there's the two that I wanted to talk about. One is Ophiocorticeps unilateralis, which is a type of yeast. Okay, because again, we're talking invertebrates, so it's gotta be like the tiniest little fungi. So a yeast type of fungi. Specifically infects carpenter ants. Now there are different types of carpenter ants, but that that that general ant.

SPEAKER_00 14:49

Yeah, we've talked about some of those. Yeah, we talked about some of the ants before too.

SPEAKER_01 14:54

Yeah. And like this specific fungi has likely been around for 48 million years from fossil evidence. So in 48 million years, it has actually only gotten more specialized rather than more generalized. So if it hasn't jumped to mammals in 48 million years, it's probably never gonna make the jump. Thank goodness. Not got all the way. Yeah. So and I don't know though, dude.

SPEAKER_00 15:20

This would be the year that it would happen, though.

unknown 15:22

Yeah.

SPEAKER_00 15:22

Like 2026. Like what else? Let's just yeah, let's just have the fungi, parasitic fungi, just jump from invertebrates to vertebrates. Might as well just be the year.

SPEAKER_01 15:34

No thanks. The opiocorticeps unilateralis. That sounds like a species, but it's actually like what's called like a not a complex, but it's kind of like that. It's more than just one species, it's like a grouping of this type of fungi. Um, and so but they're really hard to tell apart, which is why they just lump them all together like that. Normally, ants are creatures of habit and they follow swarm behavior, as we've also talked about in a previous episode. They follow pheromone trails when they're foraging and they stay with the group. Like that's the ant way. But when they're affected, when they're infected by ophiocorticeps, this changes their behavior. So the ant veers off wandering around erratically. Eventually, it climbs up to a high point, almost always 25 centimeters off the ground. Um very specific. Is it jaw? It locks it no, it grabs on within its jaws onto the underside of a leaf and dies clinging on. Okay. So they know, because of they know fossil evidence is the leaf scars that they're finding on both of leaves, knowing that the ants were doing this 48 million years ago. So after death, a stalk bursts out of the back of its head and releases spores to the surrounding area. It looks like a little like antenna.

SPEAKER_00 16:55

That's straight up ex-file's crap right there.

SPEAKER_01 16:57

It's terrifying. Like if you were the size of an ant, it would be a horrific. So how does it control behavior? I mean, it it doesn't even, we're talking about a fungi. Fungi don't have brains of their own. Um so it's it's hijacking a brain without having a brain. It's still a little bit of a mystery. They're discovering a lot about this stuff, but it's, I mean, probably not the most well-funded thing.

SPEAKER_00 17:21

Yeah.

SPEAKER_01 17:21

You know, they're finding out as they go. So evolutionary biologists have this cool term that I just discovered doing research for this episode called an extended phenotype. Did you come across that at all for parasites? Don't remember. Basically, an extended phenotype is when you it's an extension of you. So these ants are extended phenotypes of the fungi. They are no longer ants, they're walking fungi. Yeah, it's a cool concept and term. So it's it's becoming an expression of the of the parasite's genes, whether that's a parasite like we're thinking, or a fungi, a f parasitic fungi. Um, so this guy wrote, While the manipulated individual may look like an ant, it represents a fungal genome expressing fungal behavior through the body of an ant.

SPEAKER_00 18:16

Fungal behavior?

unknown 18:18

Yeah.

SPEAKER_01 18:18

Yeah, fungal behavior, right? We don't even think about fungi as really having behavior. Behavior, yeah, they do. So this guy who really knows the most about it, Hughes, he went to Thailand into this rainforest in 2006 and 2007, and he was doing a lot of research on these ants, and he kind of saw that they were walking around drunk, which seems to show that there's something wrong with the central nervous system.

unknown 18:44

Yeah.

SPEAKER_01 18:44

Um, and it does not have to be a little bit more.

SPEAKER_00 18:45

But also, if it was gonna make if if it was gonna make the jump to anybody, it would be that researcher that's up in it all the time. Like I would be wearing a mask. You know what I mean? I would be terrible. I would not be convinced that I yeah. Yeah, that it's not gonna jump. Like maybe it's because it is very out there in the rainforest and not a whole lot of people are around to do it. And so it's like I'm gonna be able to do that.

SPEAKER_01 19:04

Yeah, I just have the chance.

SPEAKER_00 19:06

Yeah, it just has now it is, and then you grow a big freaking stalk and like and then you go up there climbing 25 feet high, grab onto the bottom of a branch. Yeah.

SPEAKER_01 19:17

It's horrible, it's horrible. Well, right, because so they they they they go outside of the nest, which is also atypical behavior for the ant. It's like, all right, but there's also shows that so if an ant feels sick, it leaves the nest because it doesn't want to infect all of its nice of them. You know? So the the the paras the the fungi had to adapt to work with that behavior. If it's gonna leave, fine, you can leave, but you're gonna walk up 25 centimeters and die at solar noon is when that happens.

SPEAKER_00 19:57

Why is that you always find the most specific like animal like yeah.

SPEAKER_01 20:04

Yeah, again, this is like some witchy stuff. Yeah. Um, so they so up at solar noon, which is the optimal time for the fungi's growth and reproduction, they they looked at it and found that their heads were just packed with fungal cells and their jaw muscles had been atrophying so that when they clamped on, it was like a death grip. They never can let go. So like the fungi is not only hijacking behavior, it's atrophying their jaw muscles. Like the whole thing is just taking over. Um so they think that the fungi is releasing some type of neurotransmitter that's like serotonin, yeah, noradrenaline, and dopamine, which is I'm Okay.

SPEAKER_00 20:45

So to be fair, it sounds like a pretty sweet high as your diet.

SPEAKER_01 20:48

It's just a chemical cocktail that's making you do this. Yeah.

SPEAKER_00 20:51

So I mean, it sounds like it's you kind of slowly positively trip into your death.

SPEAKER_01 20:58

Yes. They were like, they've said they've found that serotonin going down in ants is known to prevent them from foraging, right? In other animals, disruption of these can cause hallucinations and muscle spasms. So, like, maybe they're seeing something pleasant. Maybe they're eating a giant cupcake.

SPEAKER_00 21:18

Like the grasshoppers like running out of the room.

SPEAKER_01 21:23

Yeah, right. That's it.

SPEAKER_00 21:25

Yeah. They have no clue, none the wiser.

SPEAKER_01 21:28

And it's and it's like doing stuff to their circadian rhythm. It says it secretes an enzyme that's also shown to increase activity in in the insect host, so like the adrenal the noradrenaline, and it also activates genes that cause lockjaw and suppress the immune system. So it's like, all right, you're infected. Immune system's gone. That allows the fungus stuff. Yeah, lock jaw, all of it, all of it. And finally, they also found a gene in it that has been shown to be overactive in patients with Alzheimer's disease. So they thinking it's something with the fungal cells killing and displacing the ants' brain cells. So something similar. So it's even crazier. My mind, here's where also your mind will explode again. The parasitic fungi, this particular parasitic fungi, has a parasitic fungi of its own. What? Yeah, it's called they're called hyperparasites.

SPEAKER_00 22:27

Oh geez. That's a thing.

SPEAKER_01 22:29

New fear unlocked, hyperparasite.

SPEAKER_00 22:32

God.

SPEAKER_01 22:32

But every parasite needs a pet, I guess. Like well, thank goodness it does because it basically it's the kill switch for this this this fungi. So its own one stops if without it they think it might like literally kill all ants. That's it, it would just go nuts. Already there's like you can find the entire colony in the rainforest, you'll just see a mountain of dead ants like that have been like falling eventually as they decompose because it's been happening over time. So you're like, ah, the fungus is present here. Here's a mountain of corpses. Jeez. But then it would be so much worse without the hyperparasite.

SPEAKER_02 23:12

Yeah.

SPEAKER_01 23:13

Um and and this cordyceps thing, what I have been saying is ophiocoryceps, which is actually what this is. You might have heard cordyceps before because it became super popular in the show, or the show and the video game The Last of Us. They used the term cordyceps fungi. That's in that show. It was taking over humans and stuff. Um cordyceps used to contain ophiocorticeps, but now they are separate families, so that is a totally different fungi. Um as of 2023, there are 35 known species of this that are able to control the behavior of ants, but they think that there's maybe hundreds more.

SPEAKER_00 23:52

Which is of course, yeah, because again it's a very yeah, but it's also like very understudied, and yeah, that's crazy.

SPEAKER_01 23:59

All right, and then the last, the other one that I wanted to do that actually you might be familiar with, um, is the Masospora cicadina, which is the one that infects cicadas. The, you know, where they where they mate, they like they mate and their butts fall off. Yeah, that one. Yep. So this is also referred to as an extended phenotype. So it's it's just fungal behavior. This fungi infects only periodical cicadas that come out every 13 or 17 years. It's brood eggs. So this one was the one that came out just a couple of years ago. That's what we were seeing it everywhere. Yeah, yeah. Yeah. And their butts were all gone. Um so it's the only known predator or pathogen synchronized to the cicadas life cycle. Because maybe not able to time it. Like there's no other predator of that brood that's just that.

unknown 24:52

Yeah.

SPEAKER_00 24:53

Um that's that specific for it.

SPEAKER_01 24:55

Yeah. And it has two stages of infection. So stage one are dormant spores in the soil that infect the nymphs as they crawl up through it. Okay. Those stage one infected nymphs grow up to become adults that spread stage two spores. Stage two spores go from adult to adult in the same generation. Okay. And then those infected adults drop the dormant spores for things to start all over again. So, like you can either be infected as a baby or as an adult. It's the same fungi, but it's two different ways of it happening. Right.

SPEAKER_00 25:33

Your chances just got horribly worse here.

SPEAKER_01 25:37

Yeah. Um, both stage one and stage two, what happens is the abdomen, its butt, becomes distended and you lose the last couple segments of you of your abdomen. Just your butt cheeks fall off. Yeah, you just off off some buttons. Genitalia included, sometimes.

SPEAKER_00 25:56

Poor guy.

SPEAKER_01 25:57

Which is real unfortunate.

SPEAKER_00 25:58

Yeah.

SPEAKER_01 25:59

In both sexes.

SPEAKER_00 26:00

Oh, she's a man.

SPEAKER_01 26:02

Yep. And then the breached the breached abdomen. Ugh. The open abdomen, just the open abdomen is cover. It exposes all the white spores and allows them to disperse.

SPEAKER_00 26:15

Um guys, I am so sorry that we picked this as our first episode. Yeah, that's a rough one.

SPEAKER_01 26:22

There, I dude, there was an article specifically that I was reading about this, also like the terms that it used, the language, I actually just had to copy and paste some because it was just too good the way they talked about it. Um, so here's an excerpt. Even cicadas that have lost the terminal halves of their abdomens behave as if they were sexually responsive and can be seen engaging vigorously in courtship behavior and attempted copulation with other individuals. Thus, it is relatively common to find a healthy cicada with its genitalia plunged into the abdominal spore mass of an infected partner.

SPEAKER_00 26:58

Oh, that's so gross.

SPEAKER_01 27:02

Plunged plunged into the abdominal spore mass. Um to see healthy cicadas attached to fragments of abdomen or genitals torn from their infected partners. There are pictures of Jesus, a male with female genitalia that he's ripped off of her because she's rotting. It's really like zombies having sex with each other.

SPEAKER_00 27:24

Yeah, yeah. God, that's gross.

SPEAKER_01 27:26

It's so gross. And so that's that's like what it looks like, but the way it changes behaviors, how is it hijacking the brain? Um, it seems to cause specifically males to wing flick in response. So when cicadas are breeding, males call. Females do this like like flick their wings to be like, I'm ready. This is causing males to also do that wing flick because the the fungi doesn't care how it's spread. It's just like, come breed. So everybody's breeding everybody. Male, female, male, male, female, male, like the boys are doing the wing flick, but only from stage one infection. So only if they got it as a kid. Okay, okay. So it makes and so because they it's from ones that got it as a kid and not adult to adult, that is showing that it is not physical damage that's making them do this. It's actually a behavior change. And it doesn't it doesn't take a behavior away, it adds a behavior because those males are also still breeding with females. They're just also willing to breed with males, too.

SPEAKER_00 28:32

Yeah. Um because they just they just want, I mean, the fungi just spread.

SPEAKER_01 28:35

The fungi wants to spread its spores. Um, and then they think that the compound is cationone, um, which is basically responsible for them becoming sexual zombies. It's a natural amphetamine. So they're just all amped up.

SPEAKER_00 28:49

Yeah. Like um, breeding away. Like, I gotta do it, gotta do it, gotta do it. Yeah.

SPEAKER_01 28:53

We actually use this compound in medication that helps repress appetite and heighten attention. ADHD med. I mean, it's like ADHD med. So they are hyper focused on I got to have sex. Yeah.

unknown 29:06

Yeah.

SPEAKER_01 29:06

And I don't want to eat, just bang. Um so the that's what the fun that's the fungi behavior. So essentially, this this parasitic fungi, it's a sexually transmitted disease.

SPEAKER_00 29:18

Yeah, that's what I was just gonna say. I was like, this is like a syphilis.

SPEAKER_01 29:22

It's an it's an S T that hijacks the brain.

SPEAKER_00 29:25

Um, I mean, what that's syphilis if you let it go long enough. You know what I mean?

SPEAKER_01 29:29

Like although, I mean, technically then I guess is syphilis syphilis is bacteria. Yeah, because with stuff. So, but I I don't think I guess the bacteria probably it's it's not bacteria though that's correct.

SPEAKER_00 29:43

It more like degrades it, yeah, pulls it apart.

SPEAKER_01 29:45

Yeah, whereas this is the actual, this is the fungal behavior, not cicada behavior.

SPEAKER_00 29:51

Yeah, which is nuts because I never thought yeah, again, this goes back to like I'm gonna have to look. Does tree do trees have behaviors now? That's what I'm gonna that's the rabbit hole I'm gonna go into after this.

SPEAKER_01 30:03

So, yeah, if you're an invertebrate, watch out because there are some parasitic fungi out there that want to hijack your brain.

SPEAKER_00 30:11

That is crazy, crazy, crazy. Okay, so Laura talked about the fungi.

SPEAKER_01 30:16

I'm gonna talk about parasites, which this is like like hijack brains, which is the craziest and most horrible kind of parasite you can imagine, right?

SPEAKER_00 30:24

Yeah, this is like like parasites are already bad, right?

SPEAKER_01 30:27

Like nobody wants a tapeworm, but when it can influence behavior, yeah, that's terrifying, terrifying.

SPEAKER_00 30:34

So the first one that I'm gonna talk about is hair worms, which that alone, yeah, is just this the cricket one. Uh yes.

SPEAKER_01 30:43

Okay.

SPEAKER_00 30:44

Well, hang on. Wait, yeah, yeah, yeah. Well, it multiple things, multiple things. Okay. So hair worms fall under a group called the nematophora, also known as horse hairworms. They're found pretty much worldwide. Freaking, of course, they are. As long as there's access to fresh water at some point in their life cycle. So ponds, streams, temporary pools, even I found one in my aunt's pool. I would swear I would be.

SPEAKER_01 31:11

It was like this long and going. Yeah, no, no, 100%. So I was like, that's gotta be what it is.

SPEAKER_00 31:17

Yeah, I wouldn't be shocked. Physically, again, like Laura just said, they're exactly what the name suggests: long, extremely thin, almost like thread-like worms, like gross.

SPEAKER_01 31:28

Like a spear swimming.

SPEAKER_00 31:30

Yeah. Yep. Most are just a few millimeters thick, but they can grow anywhere from a few inches to over a foot long. So you end up with a parasite, yeah, that is like wildly disproportionate to the host it's living in. I'm gonna get into that here in a minute. So their primary hosts are terrestrial insects, things like crickets, grasshoppers, and mantises, like of whatever variety. And that part does matter because they're land-based animals. They're not aquatic, they're not seeking water, and in most cases, water actually is something that they pretty much like avoid unless they have to. So, right away, the setup that I'm gonna be talking about doesn't make a lot of sense because, like Laura said, she saw it on a pool. That's where these normally live. Okay, but talking about crickets.

SPEAKER_01 32:13

Crickets can all live in there, yeah.

SPEAKER_00 32:15

So, yeah. So let's walk through the life cycle because then it's not very random. All right, so hairworms, they start in water, adults reproduce there, and the eggs are laid directly into the fresh water. Again, anything from ponds, pools, it does not matter. When those eggs hatch, the larvae don't immediately go into crickers or crickets or grasshoppers. Instead, they infect small aquatic organisms first, things like insect larvae that are already living in the water. So just find something while it's there. It's like this this will do for now. That's step one. Step two is then this transfer, all right? Those infected aquatic organisms get eaten by terrestrial insects like crickets, grasshoppers, manises, and things like that.

SPEAKER_01 33:00

Whether they like come out because Oh, right, because we're talking about larva that then hatch and fly away. Yeah, yeah, yeah, yeah, yeah.

SPEAKER_00 33:07

Yep, yep, yep, yep, yep.

SPEAKER_01 33:08

Like mayflies and stuff.

SPEAKER_00 33:10

Yep. And so then whenever they leave, then they're eaten by the crickets and grasshoppers, manises, and that's how the parasites then get into their main host. So at this point, you've already got a multiple-step system, right? You already have water, aquatic host, terrestrial host, like as it's moving.

SPEAKER_01 33:26

It might be pretty far from water.

SPEAKER_00 33:27

Yep. And so this isn't accidental. It's like it, like everything else, it's very specific, repeatable pathways that gets the parasite exactly where it needs to be. Which is like pretty much every parasite has like a cycle of steps. All right, once it's inside the terrestrial host, that's when the real growth happens. This is okay. I'm I can make it through. All right, so the worm lives in the body cavity of the insect and starts absorbing nutrients directly. It's not attached to like a specific organ, it's just basically occupying the space and taking what it needs. Like it's just in it, okay? And it starts to grow a lot, all right, to the point where you can have a worm that's several inches long inside something like the size of a little cricket. Okay.

SPEAKER_01 34:16

I've seen horrific videos of them like getting stepped on and stuff coming out. And you're like, what the?

SPEAKER_00 34:21

Yeah, it's so gross. But what's interesting is for the most of this phase, the host is still functioning completely normally. It's moving, feeding, behaving exactly like you'd expect. There's no obvious signal that something's wrong, which is, I think that's like the most terrifying part is that it's totally normal. It's just kind of there. Now, eventually the worm, when it the worm reaches maturity, at this point, it needs to then get back to water because remember, that's where it breeds is in the water. That's where all this started. Okay, but again, like I said earlier, hinted to earlier, one problem hosts don't go near water. So the parasite solves the problem by changing the host behavior. Infected insects start showing very specific shifts, they move towards moisture. Um, they're more likely to head towards like reflective surfaces, things that mimic light bouncing off water. So it's almost, yeah, it's just like, oh, what is that? Like it just starts all going towards that stuff because it just doesn't know. It's just like, oh, I I need to get there. Like, I need that. And over time, that builds to the point where the insect will actually enter the water, not stumble into it, not accidentally fall. Yep, just go into it. And again, that part, like that's the important part about all of this because that isn't random or it's not like a stress behavior, it's not like a dying animal that's acting erratically or something like that. It's like targeted, like repeatable manipulation that it like lines up with exactly what that parasite needs to finish its life cycle. So once the host enters the water, that's the final step for the parasite. The worm exits the body. It's not subtle. This can be rapid, um, physically dramatic. This long worm thread-like thing emerging from a smaller insect. At that point, the sp like it just kind of like, I don't want to say it doesn't like burst, but essentially it just like burst, right? But again, it's a terrestrial animal already in the water. It's probably already dead. You know what I mean? Like it's drowned because it's drowned anyway. Yeah. So it comes out, and then here we go. So the obvious, and then it just repeats again. So the obvious question is how is that control and all of that actually happening? Because it's not a physical force. The worm isn't like in there, you know, pulling it towards water, yeah, anything like that. So, what research has shown is that hair worms produce bioactive molecules that interact with the host's nervous system. So, this one is nervous system-based. So, while it's in there, specifically, they produce proteins that are very similar to the host's own neural proteins, things involving like signaling, um, movement, behavior, all that kind of stuff. And so that's where it kind of gets its like molecular mimicry for for lack of better terms, all right? So that start, whatever the parasite is producing, that protein, mimics its host's protein, like uh signaling proteins. And so then it just like copies and duplicates it, which is crazy. The parasite is again essentially producing compounds that resemble the host's own, and because of that, it can interfere with normal signaling pathways without the host necessarily recognizing, like, hey, there's something wrong. And so instead of overriding the system outright, it kind of like works within it, just changing the output of where it's going. So again, it's not brute force, it's like a biochemical interference on behalf of the parasites.

SPEAKER_01 37:52

And you wondered, like, is it making them thirsty? Is it like, I mean, you can't ask an insect if it's getting thirsty or why the water?

SPEAKER_00 37:59

Are you thirsty? Yeah, yeah. Why why are you going and doing this other than like it just doesn't know? So when you zoom out or zoom in either even further, like we're gonna talk a little bit about studying here, down to the molecular level, it gets even more precise. And so it's like it's cool whenever it's like a parasite, but then as people start to study it and keep going in layers and layers and layers, it actually gets like more and more fascinating because it's like, yes, it's doing this, but how? Like, how, how? Um, studies have identified hundreds of proteins produced by hairworms while they're inside the host. So it's not just like a few that it does, it produces like a cocktail of all kinds of different proteins. And a lot of those proteins are linked to things, like I said, the neural development and signal transmission. And it basically tells the system, controls it, um, how the hostes processes information and responds to it. So it isn't like a blunt, like one pathway effect. It suggests like a pretty high level of like very specific of how the parasite is interacting with the host's nervous system and how it's shaping its behavior like slowly over time. So as it's producing this cocktail, it releases these different cocktails at different pieces and parts that would go along, and it's just like a slow takeover of the parasite or of the host where it doesn't even notice. So, from an evolution standpoint, it is pretty like an interesting strategy because hairworms are classic examples of like what Laura was talking about, the extended phenotype, essentially. Because it is the organism's genes influence something outside of its own physical body. Because isn't that what you said it was? Yeah, yeah. Yeah, so this would be an example of that. I didn't come across it, but I wasn't looking for it either.

SPEAKER_01 39:46

Yeah, yeah. I just ran randomly came her all in.

SPEAKER_00 39:49

Yeah. Um, so that's hair worms, all right. Now the next one I'm gonna do um is the Toxoplasma Gandhi.

SPEAKER_01 39:58

I'm hoping you were gonna do this one.

SPEAKER_00 40:00

Yep. Yep. And of course, I mean you just had a baby, you have a cat. So I was like, well, this seems fitting. Yeah.

SPEAKER_01 40:05

So this is the one that like they actually do think influences humans.

SPEAKER_00 40:09

Oh, yeah. Yeah, well, yeah. I mean, that's why they tell you to like don't skip scoop litter boxes when you're pregnant and stuff.

SPEAKER_01 40:14

Like, not even pregnant, like they think like that this might make people more reckless and stuff.

SPEAKER_00 40:18

I wouldn't be shocked. Um, so Toxoplasmiconda is a single-celled parasite, um, so completely different from something like a hairworm, right? You're not dealing with a visible organism here per se. It's microscopic, but still capable of having pretty significant impact on behavior, obviously. Again, this one too, found worldwide and infects a wide range of animals. Rodents are one of the primary immediate hosts, and so and then cats will get into all of that. So let's go ahead and break down the life cycle, just like we did for the hairworms, all right? This one's weird, but it's not as gross as the I don't know, the hairworms just creep creep me out. Yeah, yeah. So if you look at the life cycle, it's very structured, just like everything else, like I said earlier, and it has very specific steps that it has to take. All right, it starts in the environmental stage. The parasite is shed in cat feces in the form of oosis.

SPEAKER_01 41:13

Is that yeah, yeah, or like ooosis, an oosite, whatever. Yeah, yeah.

SPEAKER_00 41:18

Oooocytes, yeah, whatever. Which are basically like hardy infectious eggs. We'll just say that. Um, those contaminate soil, water, food sources, anything in the surrounding environment. From there, it moves into the intermediate host. Rodents typically pick it up by ingesting it. Once it's out inside the rodent, the parasite forms cysts in its bodies. You'll find those in muscle tissues, but more importantly, in the brain. And then the final stage then is back to cat, right? And so it knows where to go.

SPEAKER_01 41:52

Yeah.

SPEAKER_00 41:52

Yep. So an infected rodent gets eaten by the cat, and once it's inside the cat, the parasite can reproduce in the intestines and completes the life cycle. So again, it's like, yes, multi-step system, but it's very direct. Every stage is pushing towards like one different outcome. Now, inside the intermediate host, those cysts can persist for a very long time. And it isn't a quick infection, it can be chronic, sitting in tissues, especially, like I said earlier, the brain. So, where the behavior shift of all this starts to happen is in the infected rodents, you see specific change, reduced fear of predators. All right, which is what Laura was hinting at. She said, like, oh, people get it with reckless behavior.

SPEAKER_01 42:36

I think I saw I I it could have been poison, but I did see a mouse out in the daytime once that wasn't afraid at all, and it was almost like going in circle. Like there was something wrong with it. And I was like, I wonder if this is toxo.

SPEAKER_00 42:46

Yep, yep, probably. And again, it's not like it's a uh it's almost targeted where it's not just like a strolling about its way, and then it's like, oh, there's a cat, oh whatever. No, it's like, oh, cat, like let me go see it, you know, kind of thing. Um they lose their natural version to cat odor, which I thought was fascinating. So it's not so specific. Yeah, so it's not like it's a uh it's not just a mental thing, it's like because again, rodents they smell, you know, predators coming. And they're like they that is gone. And in some cases, it actually that actually shifts into like something closer to attraction, which is what they're so it's not like it's not a oh my gosh, this is a predator, but it's like that's uh that smells good, and it starts to like again, it's so it's like very particular because again, it's the parasite in it that's like I need to get to a cat, which is also like crazy because it just so cool though. Yeah, yeah. So instead of avoiding areas where the cat has been, these rodents are more likely, like I said, to move towards them, and the outcome is obviously pretty direct. It increases the likelihood that the rodents get eaten by a cat, which is exactly what the parasite. Needs to move on to its final host stage. So, how just like I talked about the hairworms, how is the toxo actually doing this? All right. Toxoplasa is interacting with the host nervous system at a chemical level. Same thing as what the hair worms did. It alters neurotransmitters.

SPEAKER_01 44:18

Yeah.

SPEAKER_00 44:18

Yep. Yep. It it alters the neurotransmitter system with a strong link to dopamine regulation. That's like the biggest thing that they notice in these rodents. One of the key chemicals involved, dopamine is, is uh involved in like the motivation reward, but then also risk taking. So at the same time, the cysts tend to form in areas of the brain tied to fear and risk processing. So not only does it like affect its smell and everything like that, but it's also like up in the brain, like deteriorating and getting rid of it and interfering with all the neural pathways that are tied to fear and risk processing, because it just like doesn't give a shit any anymore. So you've got the parasite sitting in the brain in the exact regions that influence how this animal is going to respond to danger, and that starts to lead towards the shift in how the signals are processed, just kind of like the hairworms. Um, so again, it's not like it's a zombie, like where Laura's was more like full control, it's more like behavior modification, but yeah, I think it's gonna end data, like it's an added behavior. Yeah.

SPEAKER_01 45:30

Or it's like it's not full on.

SPEAKER_00 45:32

Taken away, yeah, yeah, because it's not afraid of the cat anymore. So it's not necessarily like a taking over of the brain, it's changing how the brain responds, but therefore it's gonna lead to its death because if it's like doesn't care about you know cats anymore, it's just gonna go whoop right to them. So there is a lot of ongoing research into the all this because again, the fear that how much does this affect humans? Um, and at the neurochaps.

SPEAKER_01 45:56

I've read some things they think that like could it have some influence on like is it a coincidence that humans who are very impulsive, like how many of us actually already have toxo? And is it just correlation or is it causation that it causes impulsivity in humans? Yes, because wouldn't that be crazy that something so little can cause people to take crazy risks?

SPEAKER_00 46:18

Yeah, yeah. And again, like the ones that they were they have suspected have it, it is like a out of out-of-the-norm behavior, but it's also like I don't know, you said earlier it's like an addition, and it's like addition through subtraction, right? So you already you should be afraid of these things, but you're not anymore. So because like that has taken away in place of it, is like, let's go do this kind of thing. Like it just has no concept. Um, so they're looking into the the just that within these rodents to figure out what the heck is all is going on there, how is it doing it, why is it doing it, and all the exact mechanism used. Another big question that they're looking at is why does this specifically affect fear of cats? Because it's not like the rodents are lose their fear of all predator. What? Right, yeah, yeah. Yeah, it's just cats. Yeah, it's just cats.

SPEAKER_01 47:16

Because other things eat rodents.

SPEAKER_00 47:18

Yep, nope. Why don't they lose their fear of owls or their fear of specifically to cat?

SPEAKER_01 47:24

It's gotta be because the cat intestine is most hospitable.

SPEAKER_00 47:27

That's what I was just gonna say. I I would assume that that's it. Or if it is like a a if it needs like the smell and fear kind of thing, like you're not gonna necessarily smell an owl, you know, just like you would smell a cat, because it's gonna leave like a trail.

SPEAKER_01 47:43

Yeah, more are they just more likely to run into a cat than any other predator? I guess so the parasite has evolved to be most common predator.

SPEAKER_00 47:52

I guess. I don't know. I guess, yeah. So they're looking at, like Laura said, correlation versus causation, what is going on there? So looking into that, because you know, risk taking, reaction time, decision-making patterns are altered, it's important to understand and to so that we can as humans be more careful because if this starts to affect humans more, it's like crap. So again, it's it's small, you're not gonna really see it. Hair worms are so disgusting. Um jeebies just gross all the time.

SPEAKER_01 48:23

Fungi isn't a problem for us, at least the parasitic now, now yeah, right?

SPEAKER_00 48:29

All right, guys, that wraps up our first episode. So, just like the previous few seasons we've done, we're gonna be doing uh mini episodes, and this one should be really fun. Um, these are uh animals you've probably never heard of or things you've never heard of. Is it animal specific? I can't remember. Specific. Yeah, so it's animals you've never heard of. We're gonna be talking about all like the very niche, very like specific things that just aren't mainstream. So next week it'll be the mini episode before we're back to a longer episode, and then we go mini episode, and we keep rotating like that. So yeah, that is uh nature zombies. Stay away from cat poop, uh, don't be a cricket or grasshopper or an ant. Yeah, right? That's or cicadas. Yeah, or cicada. That's that's our our life lessons, our takeaway message for you today. Just don't don't be any of those insects.

SPEAKER_01 49:20

Yeah, actually, I'll leave you on. So people, because of the cicadas, it's an amphetamine. Some people were like, well, if I eat enough, will I also have you know infect me like methamphetamins? No. They said you'd have to eat so many cicadas for it to be a thing, it'd be disgusting. Like spore infected No. Don't do it, guys. Don't do it.

SPEAKER_00 49:44

We'll leave you on that note then. Doctor next time. All right, bye.