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December 12, 2017 53 mins

The fungus Ophiocordyceps unilateralis is the Mona Lisa of mind control parasites. In this episode of Stuff to Blow Your Mind, Robert and Joe discuss the latest findings on its insidious ant-hijacking antics -- as well as a few other favorite biological puppet masters.

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Speaker 1 (00:00):
My lady. Welcome to Stuff to Blow your Mind from
how Stuff Works dot com. Hey you, welcome to Stuff
to Blow your Mind. My name is Robert Lamb and
I'm Joe McCormick. Hey Robert, what's your favorite Possession movie? Oh? Well,

(00:21):
there's so many. I guess I've reached the point where
I'm not as into Beamon Possession. I want a movie
about robots possessing people, or alien entities possessing people, or
of course, um weird uh angelic christ figures from another
planet possessing people, such as in Larry Cohen's God Told
Me Too. Oh yeah, there you go. How about in uh?

(00:43):
Maybe my favorite is The Visitor, You know that one
filmed in Atlanta in the nineteen seventies. You get to
see the uh, the old highways and everything, but it's
got that Italian sheen and there's a little girl who
gets possessed by I think a satan from another planet.
Oh yeah. John Houston ends in that one, right, and
I think a very disoriented Sam Peck and Pop plays

(01:04):
a doctor in it. Cool. You know another one that
comes to mind is of is the Toho horror film Matango.
Are you familiar with this? One. I know about it
because you've mentioned it, but I've never seen it. Oh,
it's a it's a fabulous story about a weird fungus
on essentially a monster island. It's probably somewhere in the
uh in the region of Monster Island, like the King Kong. Yeah,

(01:28):
and it this fungus takes over people's bodies and gradually
turns them into not only a fung gi infested humanoid monsters,
but into a straight up locking mushroom of death. That's awesome,
But to what end? Like, what do mushrooms want that
they can't get on their own and they need a
human body for well, you know, mushrooms need to move

(01:49):
around mushrooms. Mushrooms of course, just need to reproduce and
spread and continue the genetic mission. And sometimes that involves
in fiction walking on two legs or in reality walking
on say six legs. WHOA. And that brings us to
our topic today, Robert I would say, this is one
that has been frequently requested by listeners. I think, um,

(02:10):
it's a topic that if you're one of these parasite
fan geeks, like a lot of you out there are,
we know you've probably heard of this before. But we've
gotten a lot of requests and it's a great topic.
We've never devoted a full episode to it before, so
I think it's finally time to talk about O fe
O Cortus ups. That's right, especially since there's actually an
update to the story. Yeah, that's the really exciting part

(02:31):
here is that because we've we've touched on it before
in past episodes, but this time we get to cover
it in more depth and discuss the latest information. And
the cool thing about the update is that it's it's
definitely a positive one. I noticed very often because we
try to practice responsible scientific skepticism on the show, that
whenever you get an update to a sensational science story,

(02:54):
more often than not, the update is that really sensational
thing you learned last year actually is wrong, right, and
now you know, I can see where that can turn
people off. Every now and then. I mean sometimes it's
something like oh, Plute, you know, Pluto has lost its
planetary status and you feel a little hurt by that
sad trombone. Yeah, or A big one that I've noticed
with people is finding out or being being told that, say,

(03:17):
a Tyrannosaurs rex had feathers and then that kind of
destroys your childhood dream or your cinematic vision of what
a t rex should be. And uh, and I have
I think we were both in agreements that dinosaurs with
feathers are cool, uh and actually scarier, yeah, and and
scary especially, Yes, a fuzzy Tarrannosaurus rex, you know this

(03:40):
to be true in your heart, is scarier than one
with just regular lizard scales. Yeah. But I have to
say this case with with the o fiol Cortis EPs,
this is not a case of feathered dinosaurs. This is
a case of the new scientific information making an already
terrifying scenario even more frightening. And and and it already complex, uh,

(04:03):
system of parasitism even more complicated. Absolutely, So before we
lather up your brain with those nightmares, I figured we
should take a look generally at behavior controlling parasites as
a sort of class of organism, because that that's where
the OPEO Court accepts really gets its reputation, is the
fact that it is a fungus that has some control

(04:26):
over the behavior of its host. And it's not the
only organism like this in the world. Oh no, they're
They're numerous examples that we could spend a great deal
of time going through not even all of them, but
just some of the key examples. We're not gonna do that.
We're gonna hit like maybe three, I think. Uh. But
the thing is, you have to, you know, way, you
have to appreciate these simpler models of of mind control

(04:51):
of parasites in order to appreciate what is essentially the
Mona Lisa of mind control parasites as eyes follow you
no matter where you go. Yeah. Well, and it's just
it's just the pinnacle of of complexity and and beauty
if you find organisms of this sort beautiful, also like
the Mona Lisa surrounded by people taking pictures of it constantly. Yes, indeed. Okay,

(05:12):
So this first one we're gonna look at is when
you've probably heard of before because it is the result
of a panic, and I will have to debunk one
of the creepier parts of the panic about this, but
the organism itself still is very cool. So this is
gonna be Toxoplasma gandhi um. This is a microbial protozoan parasite.
It's responsible for the disease toxoplasmosis and animals and lots

(05:35):
of humans and pets are today already infected with T gandhi.
They get infected at some point in their lives. But
there's only one known animal host that allows this parasite
to achieve sexual reproduction. And that host is, of course,
our lord and master, the common cat. Uh. It might

(05:55):
be inside you right now, but if so, it's not
having sex. It's only having sex if it's in your cat. Yeah,
and it's It's kind of like with people that travel around. Uh,
you're more inclined to look after your home, I guess.
And then when if you're staying in a hotel or
a guesthouse, then you know who cares. You can just
rerect the place. That's kind of what occurs with with

(06:16):
with with with the T. Gandhi is that the catalone
is unaffected. It's every other species that seems to be
warped to some degree by its occupancy. Right, So, if
you're imagining what life is like as a parasite, you
might think, Hey, it's great, I can infect all kinds
of organisms. But that's not necessarily great, is it? Because
what if you need to get into a cat to reproduce,

(06:38):
but you're stuck in some other organism You've infected a
human or something like that. You're basically going nowhere, right,
So many of these parasitic cycles and their love. I
love looking at illustrations of these cycles. It's it's it's
kind of a careful platforming video game. You have to
jump from here to here to hear in order to
complete the cycle. And if you miss that jump, your toast.

(07:01):
And also if you jump to the wrong organism, your
potentially toast. Uh. Or if you wind up in the
right organism but end up in the wrong portion of it, uh,
your potentially toast and so is the host. Right, So
let's chart those jumps. Let's say you are a colony
of t Gandhi and you're stuck inside a rat and
you've got a hanker in for some sexual reproduction. What

(07:22):
are you gonna do? Like, you don't have a way
to hop out of the rat and go looking for
a litter box to stake out. Uh, you don't have legs,
So you've got to find some way to get the
rat into the cat. Yeah, You've got to essentially steer
starship rat into the cat. And for a while it
was hypothesized that parasites like this might actually control the

(07:44):
behavior of the host in order to get where they
needed to go. And in the case of rats infected
with T. Gandhi, recent studies have shown that this is
exactly what happens. So I want to look at one
study published in the year two thousand in the Proceedings
of the Royal Society of London b Biological Science is
and this was by Manuel Burdoi, Joanne Webster and David McDonald.

(08:04):
And this is called fatal attraction in rats infected with
Toxoplasma gandhi. So the study tested the exploration behavior of
rats infected with T. Gandhi and a control group of
uninfected rats in an outdoor pin during the night. And
in these pins there were areas marked with various odors.

(08:24):
So you'd have a neutral smell. This would be clean
straw bedding, a quote own smell like your own smell,
which is the rats own straw bedding. You can probably
guess this smelled like the rats own urine. You had
a rabbit smell, which was rabbit urine, and you had
a cat smell which was cat urine. And what did
they find. Well, unsurprisingly, the control rats, the rats that

(08:46):
did not have the toxoplasma infection paid a lot of
visits to the areas marked with their own smell, but
they really tended to avoid the areas that smelled like
cat urine. You don't want to hang out where your
worst nightmare takes bathroom rakes. But the T gandhi infected
rats made way more visits to the cat urine marked areas.

(09:07):
The way the researchers described this, it wasn't just that
the parasite infection made them less afraid of cats. It
manifested as a kind of bizarre suicidal attraction to the
smell of cats. So it looks like what's happening is
that T. Gandhi uh manipulates the behavior of its rat hosts,
causing them to wander around in cat country until they

(09:30):
get eaten. And then when the cat eats the rat,
the rat contains tissue cysts of the T. Gandhi that
infect the cat, and then the protozoan can finally get
around to some sexual reproduction. And I think this is
interesting because it's it's a really devious trick, but one
that strikes me is not necessarily complicated within the rat.
It's kind of a flipping of a switch the reversal

(09:50):
of a setting. Yeah. Yeah, I think it's possible that
all you'd have to do here is find a way
to turn off the avoidance component of the rats natural
fear respon aunts. Uh And and once you've done that,
the arousal component of the fear response, unchecked by avoidance,
could sort of lead to these suicidal type behaviors on
its own. Now, that alone is pretty fascinating. I And

(10:13):
I've I've I've written about toxo it seems like countless
times over the past ten years or so. Um And
I'm always just intrigued by that basic concept. But some
have taken it even further and uh and have looked
at what is toxo potentially doing to humans? Yeah, and
for many years, I think there was legitimate worry that

(10:35):
will if it does this in rats, is Toxoplasma gandhi
leading to some cases of human mental illness or risky
behavior patterns in humans. It's a reasonable thing to wonder about.
But I do want to quash the panic here. Given
more recent research, I think it's unlikely because um so,
there was a twenty sixteen paper by Karen sugged In

(10:57):
at All published in plos one, and it tried to
track the effects of toxoplasma sero positivity and a sample
of eight hundred and thirty seven subjects, twenty eight percent
of whom were positive, and other than an extremely small
average increase in the number of suicide attempts, there was
no measurable psychological difference in humans with toxoplasma infection in

(11:18):
those without, and the suicide attempt difference is small enough
that it, you know, could be noise, uh to quote
from their conclusions quote On the whole, there was little
evidence that t GANDHI was related to increased risk of
psychiatric disorder, poor impulse control, personality aberrations, or neurocognitive impairment.
So don't worry too much about the toxoplasma in yourself,

(11:41):
all right, That's that's good because because like I said,
I've I've covered toxo enough over the past ten years,
and I've been a cat owner of the past ten years.
So you can't help but fall into some at times
almost kind of supernatural. Thinking about it, you're like, well,
there might be nothing to this, but if there is,
I sure am around a cat a lot. And and
then you start like second guessing all your motivations in

(12:03):
your life and your behavior and wandering. Just how much
of you is in your in your actions? How much
of it can be blamed upon the cat? Why can't
I stop gambling? It's my cat. Yeah, alright, we're gonna
take a break and we come back. We're gonna roll
sit through some more examples before we move on to
our prime brain hijacker today. Thank hey, alright, we're back.

(12:26):
So this is another favorite of mine, and I've actually
told stories about it, like personal accounts of this parasite
in the past on the podcast, but I'll spare everyone,
uh the the actual tales. But what I want to
talk about our parasitoids from the phylum uh nemato Morpha.
They're also known as horse hair worms because these threadlike

(12:48):
roundworms resemble the hair of a horse's tail or maine
and as larva. They take up residents inside a cricket,
a mantis, a beetle, or other host organism, but as adults,
they're free living organisms that live generally in like shallow
pools of water or really damp soil. Now male and

(13:08):
female horse hair old horse hair worms mate in that
damp soil or the fresh water, and then the females
lay millions of eggs. So we have a similar situation
though about these eggs have to these eggs that need
to go somewhere. They need to complete this cycle. You
need to get from one place to another, but you
can't crawl there. Yes, so these eggs what they do
is they they hatch and then the tiny larva insist

(13:32):
on vegetation near the water's edge, so they form these
like hard structures. So let's eat N C Y S
T not I N S I S T. They can't,
they can't. They can't insist upon anything, but they can
insist a leaf. So they're on the leaf and then
up pops a cricket or other suitable host drops by
and it eats this increase this insisted larva along with

(13:55):
the vegetation, or in the cases of say carnivorous mantis,
it acquires the parasite by devouring an already infected intermediate
hosts such as a mosquito larva. Now, once inside it's
target host, the cyst covering dissolves and it allows the
juvenile worm to escape, bore through the gut wall and
start absorbing nutrients, and then it grows and grows, just

(14:18):
becoming just a longer and thicker um worm inside the creature.
Just you imagine it just coiled and coiled inside the
body cavity. So if you're the insect, it's like, congratulations,
you've got a new major organ right. Yeah, it's essentially
a xenomorph. It grows until it's time to just burst
out um and Uh, here's the thing. It'll it'll certainly

(14:40):
abandon ship if the host dies. Uh. And that's that's
what I have observed in the past, Like somebody stomps
a cricket in banned class because they think the crickets gross,
and then this disgusting organism emerges from the cricket. Yeah,
but of course it doesn't want to emerge on the
floor of of your band room. It wants to emerge

(15:01):
near freshwater or damp soil. So how does it get there? Well,
there are two theories here. Uh. One is that the
worm instills a crazed thirst in the host so that
it seeks out water. So it's like, I'm so thirsty,
I must go to a large body of water, right,
and then the second one is the worm. The second

(15:23):
theories that the worm simply waits until the host finds
water on its own and then it bursts forth. Okay,
so it's like I detect that your body is filling
up with liquid. Right now, it's time to jump out.
We must be in an area with liquid. I shall
jump out now and hopefully find the habitat I need now.
According to a two thousand and one paper from the
German journal Zoologishier and Zeiger, the thirst hypothesis is supported

(15:48):
by observation observations of suicidal behavior in infected mandis is
in southern France that seemingly jump into the river and
give birth to the worm that consumes them. And by
the way, sometimes it's twins. Sometimes they don't have one
enormous uh nematode growing inside and they have to. So
you can't really on the second hypothesis, just waiting until

(16:12):
it's drinking, explain all the like suicidal jumping into water.
Right so it's it seems like there's reason to lean
in the direction of of of of mind, control my manipulation. Uh.
And then in this case it is as with the
the the rat and taxo seemingly fairly simple. Make your

(16:34):
host feel thirstier than normal when you are ready to
emerge and find water. Well, I admit that's a good one.
But how about some parasitic wasps. Well, I certainly love
parasitic wasps. I love I love wasp and bees in general,
and I continue to find tremendous joy in the fact
that my five year old son's only imaginary friends are

(16:54):
his quote be and wasp friends. So he has, Yeah,
he has two bees and two wasps. Are they nor
normal sized or they larger than normal their normal size?
And they live on his head or sometimes they're flying
around his head? Uh and uh yeah, and I'll forget
that they're there, and then suddenly he'll bring them up,
and that's I presume they are always there to him. Now,
are they anthropomorphic? Do they speak? No? No, I think

(17:17):
the only difference is that they don't sting, except that
they will sting like monsters or bad guys or something.
I think that's been explained to me. But otherwise they're
just animals. So I really and I really like that.
But as in two bees and wasps, as my son is,
I don't think he's ready for the truly diabolical. Examples

(17:38):
of parasitic wasps that really out body horror are grimms nightmares.
Al Right, So just a little background parasitic. Prehistoric parasitic
wasps as far back as the Jurassic period, they would
use their pointy um ovipositors, which is a female only
reproductive structure, to lay eggs directly onto living insects such
as caterpillars, which the hatching larva would then consume. But

(18:02):
why lay your eggs on a caterpillar when when with
a little evolution, you can lay them directly inside your victims.
Essentially that you're using that ovipositor as a as a
surgical device, So it grows into a sharp, sometimes saw
toothed instrument that helps a wasps better performed than necessary surgery.

(18:23):
And since the chosen insect hosts tend to take offense
and fight off the wasps. Of advances, the ovipositors also
evolved a pack a venomous punch, and so like the
the end result is you see something like a honeybee,
which doesn't engage in this kind of parasitic activity at all,
but still retains a potent ovipositor. Oh yeah. Now, a

(18:45):
number of modern parasitic wasps continue this very practice, though
either peppering the outsides, or filling the bodies of their
hosts with sometimes dozens of eggs. Other wasps evolved away
from the practice, but even with them, for the venomous
stinger remains uh not only no longer an instrument of reproduction,
but a potent biological weapon. But some of the examples

(19:06):
of parasitic wasp eggling are rather straightforward, while others are
are just really diabolical. H. Such is the case of
dino campus cocanelle, a common parasitic wasp of the spotted
lady beetle uh Colio megala macu lata. So the essential
reproductive strategy here is much the same with many other

(19:28):
species of parasitic wasp. She uses her ovipositor to surgically
implant her egg inside the body of the chosen host organism.
But where this gets crazy, though, is when the actual
emergence occurs, what you might refer to as a chess
burst mitzvah if you will. Uh, that's when that's when
it gets really weird noteworthy. So normally, uh, you know,

(19:51):
you would expect a host organism to mercifully die at
this point, you know, I mean, that's how it goes
down in the alien movies. Right, once the xenomorph has
emerged from your boddie, you you blessedly expire. Right, You're
not walking around for a few days with it poking
out of your stomach. Right? Uh? That that would be
a fun Halloween custome, I guess or the puppet built in. Uh.

(20:12):
But but where this example gets gets weird though, is
that not only does the host organism live, not only
does the ladybug live, but a little behavior modification forces
it to hang around and quote unquote guard it's parasite
baby as it grows into adulthood beneath its protective bulk.
And scientists believe that what's happening here is the secretions

(20:37):
left by the larva when it bursts out might play
a role in reprogramming the host. And then you would think,
all right, well, finally the ladybug gets to die. But uh,
you know you would you would think, surely it's it's
suffered enough and it can just it can it can
be at peace. But there's no such luck because you know,
this is the insect world and things you're a bit
cruel and and weird. No insect politicians, us, yeah, us

(21:01):
as the great brundle fly told us. So researchers found
that twenty of manipulated ladybugs recovered normal behavior following this ordeal.
What so they gotta go around with with the memory
of this good thing. They probably don't have episodic memory.
They just that also speaks to just the sturdiness of

(21:21):
of insects. Really, to to thrive in such a cruel world,
you know, you you've got to be incredibly resilient. So
that's one of my favorite examples of of of of
parasitic behavior parasitic reproduction with organisms. Well, Robert, I think
you're wrong. I think that is an ideal imaginary friend
for a child, because this imaginary friend not only might

(21:43):
sting bad guys and monsters, but could enslave another insect
to protect you from bad guys and monsters on its behalf.
Oh yeah, I mean they're ultimately they're kind of terrifying organisms,
aren't they, at least if you're if you're a ladybug
or say tarantula. So that's another thing I can only
I can see, like some people are afraid of spiders, Well,

(22:04):
then if you're afraid of spiders, then you have to
be a huge wasp fan because you know they go
around just terrorizing the but Jesus out of out of
spider populations. I don't know if you've ever bust open,
like as a child, dirt dauber nests and see like
all the spiders that they stuffed in there for their
larva to consume. It's pretty wonderful, all right, but still

(22:25):
as beautiful as these examples are. Again, these pale in
comparison to the Mona Lisa of parasitic brainwashing. Right, crowd in,
get your camera ready, it's time to visit the masterpiece.
And so picture this a carpenter ant colony in a rainforest.
You're gonna be in maybe the Amazon or in a
tie rainforest. And so you'll see thousands of ants swarming

(22:49):
around on the nest or traveling out down the trunk
of a tree into foraging trains. But if you look close,
one of these ants is not moving along with the others.
Instead of moving along in a train or swarming, it's
frozen in place, and its body is sort of curling
up around itself, almost like it's trying to touch its

(23:12):
head to its anus, and it's curling and writhing and
pulsing its whole body, and it keeps scraping at its
antennae with its four limbs. Something's obviously wrong with this ant. Yeah,
that ends on right at all? No? Uh? And then
finally it falls from its nest to the forest floor,
and from there it begins to move slowly, almost like

(23:33):
it's drunk, sort of crawling around awkwardly, and then eventually
up the stalk of a nearby sapling plant. And when
it reaches just about twenty five centimeters above the forest floor,
it aligns its body with the primary vein on the
underside of a leaf, and then it clamps down as
hard as it can with its mandibles. The ant will

(23:55):
never leave this spot. Within a few days, the ant
is going to be dead and its jaws will still
be locked onto the vein tissue of this leaf, and
a crazy looking thing will start to happen. A huge
spike starts to grow out of a hole in the
back of the ant's head like this gigantic single devil horn,

(24:15):
growing longer and longer, longer than the ant itself, until
it becomes clear that this spike is a killer mushroom.
It's the fruiting body of a parasitic fungus called Opio
cort accepts unilateralis. Now, there are a lot of species
of related intomate parasitic fungi, each targeting a different host organism.

(24:35):
Unilateralis specifically targets carpenter ants and their close relatives. Now
you might be wondering, why did that observed behavior take place?
Remember all the stuff the ant did to review then
becomes infected with the fungal parasite. It climbs to a
leaf tis off the forest floor, It clamps on with

(24:56):
its mandibles. It dies, and then the fruiting body of
the fungus erupts from the ant's head and grows long.
So why does the ant go to the leaf? Like?
Is this just it's preferred place to die. It's true
that ants are social insects, and Robert, I don't know
if you've read this before. Sometimes they will intentionally remove

(25:17):
themselves from their colony when they develop an infectious parasite.
I don't know if i've read that before. I certainly
read about them removing infected individuals from the premises. Yeah,
that's definitely true. When they when you detect an infection
on your fellow aunt, it's like, okay, time to go
on a trip, buddy, and they carry you out away
from where you can infect other ants. Um. But yeah,

(25:41):
so you have to be wondering, like, is this some
kind of social insect altruistic act? Is this like the
elephant graveyard for sick ants? Know? The truth is a
lot creepier. Instead, we should ask how does the fungus spread, Like,
how does it reach new hosts? Well, it spreads by
infecting ants with its spo corrors, which are produced by

(26:01):
these fruiting bodies, the bulge just below the tip of
that fungal head spike, which the spike is known as
the stroma. And what's walking around on the forest floors
beneath the dead ant and its head spike, more ants,
more hosts. So the ant doesn't climb the leaf because

(26:21):
it wants to. The ant climbs the leaf because somehow
the fungal infection makes it climb the leaf. The behavior
is not for the good of the ant, it's for
the good of the fungus. It's essentially going home. It's
it's reaching higher ground and then saying take me home.
Next phase in my my parasitic journey, Yeah, let us

(26:42):
begin the death reign uh so, the fungus often now
gets an additional appellation, not just Opeo cortescepts unilateralice, but
Opio cortcepts unilateralice sin sue latto, which for some reason
keeps evoking the spirit of like a tool album name.
Does it? Does it reminds me of a Uh so,

(27:02):
since you lato means broadly speaking in Latin, and this
indicates that scientists believe the correct taxonomy of this species
and its related cousins of fungi basically have not been
fully sorted out yet. Strains of this fungus ultimately might
get sorted into different genus and species categories. That could change,
because yeah, we have a number of Opio Cortaceps and

(27:24):
also Courtceps as well. I think courtceps is is like
an archaic terminology for like Opio Corteseps used to be
known as court a sceps. A number of these species,
these particular species, when you look at them, uh, the
the older studies are just saying court sceps as opposed
to Opio Cortceps. Yeah. So basically there's some some taxonomic

(27:45):
stuff that's still being worked out, and so the sinsu
Lato is on there to let you know, like this,
these words could be different in the future. Yeah. Now
it's someone might be inclined to think that. The scientists
just realized that everyone had court SEPs down and then
and they thought, well, we need to make that word
a little more complicated. Let's let's add a few more
syllables to the name. Well, I mean a lot of
people still just say court a sceps when they talk

(28:07):
about this. I know I I often do so. One
of the big researchers and o feo court a sceps
has been the entomologist David Hughes at Penn State, and
one of the interesting things he points out about this
is that it's an example of what Richard Dawkins called
the extended phenotype. So in an organism, the phenotype is

(28:27):
all of the externally observable characteristics that emerge from that
organism's genome acting within its environment. So your personal phenotype
includes your hair, your eyes, the shape of your body,
your height, but also your behavior, Like if you like
black licorice, that's part of your phenotype. The way you
talk is part of your phenotype. But when Dawkins coined

(28:50):
the idea of the extended phenotype. He was pointing out
that the externally manifested effects of our genes are not
only the parts of our body and the behavior a
viers of those parts, but also external effects and artifacts
within the environment and even within other organisms. So a
beaver's dam is part of the beaver's extended phenotype, and

(29:14):
cars and toasters are part of the human phenotype. But
these are all things that these organisms have made out
of the natural world, right, they are products of that
organism's genes interacting with the environment. Now, how does this
apply to the OPEO court ACEPS. Well, look at the
infected ant, Hughes has written. Quote. While the manipulated individual

(29:36):
may look like an ant, it represents a fungal genome
expressing fungal behavior through the body of an ant. So
if the ant's body is doing the climbing and the clamping,
really it's the fungus and its genes that are driving
the behavior. This is what you're looking at now, is
a fungal organism. It just happens to be inside an

(29:57):
ant's body. Yeah, it's how different it, I mean, it's
rather different, but it's you could compare it to say,
a human being who's wearing an all leather outfit. You
know they are. They are kind of wearing the carcass
of a pig. It may be a very stylish carcass
of a pig, but you know, to what extent are
they You're not looking at pure human anymore. Right, From

(30:19):
from a sort of like a survival and reproduction point
of view, that thing crawling around is fungus. It's not
ant anymore. It's not insect. So I just wanted to
talk about a few more interesting facts about the the
FEO Court accepts. Now these are previously established facts, right
or yeah, getting into any of the words this is.
This is not from the new paper yet. So one

(30:41):
of the things is how does the spore get into
the ant's body. We know, we've said that there's this,
you know, once you create the stroma and it's hanging
off the leaf and it's raining down the death rain
is falling on the forest floor, it's spreading these spores.
But what happens, Well, the spore enters the ant's body
by penetrating the cuticle, and it does this with the
help of a corrosive enzyme that eats through the ants

(31:05):
tough exoskeleton. So the ant picks up a killer spore
from the rain of death zone, and then the spore
attaches to the ant, and then it pushes through the
ants exoskeleton with a mix of this solvent enzyme and
mechanical force. And then once the fungal cells are inside,
they multiply within the fluid of the ant circulatory system.

(31:26):
Now we should we take a pedantic note. Some articles
have been using some articles have been using the word
blood like ant blood um. I think even some entomologists
would probably say that for shorthand, but there are we
should make clear differences between vertebrate and insects circulatory systems.
Um So, ants and other insects have a very different

(31:46):
kind of circulatory system than vertebrates like us do. Insects
do not have a closed circulatory system of tube shaped
blood vessels, and they also don't have blood technically. What
they have is known as an open circulatory system, where
a pumping organ distributes this heterogeneous fluid around inside the

(32:06):
body cavities and all of the major organs are bathed
in this sort of open sea of fluid. As we said,
the fluid is not blood, but it's this substance known
as hemal lymph, and the hemal lymph doesn't have red
blood cells, so it's not the major way of distributing
oxygen throughout the body. Instead, it does distribute nutrients and
it does remove waste, but in a slightly less organized

(32:29):
fashion than the blood of vertebrates. But if you want
to call it blood, uh, just for the simplicity of
explanation than by all means. Yeah. Now, the parasitic fungal
cells get into this fluid and then they multiply inside
the ant's body for about sixteen to twenty five days
until they reach the point where the ant begins to
display the characteristic biting behaviors, the mandible clamping of unilateralis infection.

(32:56):
The ant bites down on a leaf for another piece
of plant matter, usually the main vein on the bottom
side of a leaf, with its mandibles, and it doesn't
let go. Now, I wanted to mention a few more
interesting behavioral facts from a study by a team led
by David Hughes that was published in BMC Ecology inven
and they studied unilateralis in a tie rainforest and found

(33:18):
that the infected ants like one thing you might wonder
is how do they get around? Right? Does does the
fungus actually direct them to, like here, go to that
sapling and crawl up instead of what they found there
is that the infected ants sort of display random walking patterns.
It's almost like they're they're just sort of like trying
directions randomly, and if they try to climb back up

(33:42):
to their nest in the canopy, convulsions will make them
fall off and fall back down to the forest floor,
so they're sort of bound to the earth. Now. Eventually,
this phase of erratic wandering around stops when they find
a leaf and then they do the death grip. So
they say, quote transitions from erratic wandering to death grips
on a leaf vein were abrupt and synchronized around solar noon.

(34:07):
That's kind of odd. So if we were to imagine
this with a like a fictional humanoid zombie, it would
be like the zombie bumbles around the apartment building until
it just happens upon the roof. Yeah, but once it's there,
it's it's time to get down. Well, I don't know
what the equivalent would be. It straps itself to the
helicopter landing pad or something. Um waits for a helicopter

(34:29):
and then uses that to spread its spores as it
just breaks into a thriller dance. Then that might be
the final stage really that we're supposed to witness. There
you go? Or does that? Does that party from Independence
Day on the roof of the skyscraper or they all
say welcome now. Once the ant climbs onto a leaf
and locks onto vein tissue with its mandibles, quote, extensive

(34:50):
atrophy of the mandibular muscles sets in, and this is
kind of interesting. So it gets the ant to bite
down and then it attacks the mandibular muscles of the
ant to say like, okay, you're that. That's it. You're
not doing anything else with these muscles from now on.
So it can't really let go, uh, And so it's
it remains stuck to the leaf like that after it dies.

(35:13):
And the atrophy seems to be caused by high densities
of single celled stages of the fungus inside the ant's head.
So the head fills up with fungal cells and they
make the mandible muscles atrophy away, and then you're just
locked on there like a vice. So this is all
pretty terrifying. I mean, there's a reason that this story
and and all the research that's associated with it keeps

(35:36):
grabbing headlines, it keeps influencing. Uh. You know, not only
are our science journalism, but even our fiction. Uh you know,
various uh of film and video game properties have have
been directly influenced by this fabulous model. Yeah, I know
it's been in some movies. I haven't seen the movies.
The a strain of the Court accepts fungus is the

(35:56):
zombie creating parasite in the video game The Last of Us,
where the basic concede is that this type of parasite
has jumped into human hosts. Yeah, it's It's even popped
up in Dungeons and Dragons, where you have a lot
of you know, fungal creatures in the under dark. And
the recent campaign Out of the Abyss uh includes some
some some illustrations and descriptions of particular mind controlled fungi

(36:20):
that like take over characters and then eventually causes the
mushroom to pop out of the top of their skull.
Is it mushroom shaped on the head or is it
more like the stroma we've seen here, like a big
spike with maybe a ball. Towards the end of it,
it was more abstract like that. Yeah, at least the
illustrations in the book depicted as such. So um so
it's yeah, it's it's a very inspiring model. And if

(36:41):
we had, if there had been no further research on it,
I think it would have continued to inspire us. But
when we when we come back from this last break,
we will get into this new research that that really
makes the whole prospect even more terrifying. I think, alright,
we're back. So what is this recent development in the

(37:02):
world of court accepts fungus. Well, I I will say
I first found out about this uh in an article
by one of my favorite science writers at The Atlantic,
Ed Young, who wrote about this in November. So we
went back and check this out, and some of our
listeners sent us this article and we're like, hey, are
you ever gonna do you know? Uh an episode on
the subject. So I guess that's how we ended up

(37:23):
here today. But believe it or not, the story about
the Opeo Court ACEPS is even creepier than we first realized.
I think we've been through a couple of stages of
escalating creepiness, so it has been well established that the
fungus manipulates the ants behavior. It forces it to climb
up into the air about twenty five cimeters over the
forest floor and become this possessed spore bomber, just a

(37:45):
reigning death upon the other ants from its colony. But
it was not yet understood exactly how the fungus got
the ants to follow this complex and highly specified behavior.
After all, this isn't exactly something simple, you know. It's
not just like make the ant freeze in place so
it's vulnerable to predators, make it want this food instead
of that food, or make it run around in random

(38:08):
erratic motion. Uh. It requires the ant to find the
plant stock, climb up the sapling to a very specific height,
and then clamp onto the plant with its mandibles and
never let go that. That is like weirdly specified behavior, right,
And if I had to guess, I'd assume it did
this by invading the brain with its cells and then

(38:29):
either mechanically attacking or chemically attacking some brain tissues to
trigger a series of instinctual behaviors in the ant to
make this take place. Now, there may very well be
some of that going on in terms of chemical triggering
of behaviors. Right, there's a twenty seventeen study by Frederickson
at All in Proceedings of the National Academy of Sciences

(38:52):
just this year called three Dimensional visualization of a Deep
learning model reveal complex fungal parasite networks in behaviorally manipulated ants.
And in this study, researchers created a three D model
of an ant infected with unilateralis to see what all
of the fungal growth was doing inside of the ant's body.

(39:14):
So how did they do this? Well, they use scanning
electron microscopy and uh so this actually involved making very
very thin I wanted to say paper thin, but much
thinner than paper ant slices. They so they took an
infected ant and sliced it into segments that were each

(39:34):
just about fifty nano nanometers thick apiece. In in ed
Young's article, he says that the ants were quote Julie
end was a really amazing word choice. But the thickness
of these slices is roughly the length of a single
hepatitis virus. So we're talking about seriously thin possessed ant slices.

(39:55):
It made me think about that scene with the garlic
and good Fellas. I've yeah, I just assumed this is
like a torture scene with Joe Patty, like he's slicing
people up like garlic. No, that'd be amazing. No. In fact,
it's a cooking scene. There's a scene where all the
all the mob bosses are in prison together except for
them because they pay off the guards and everything prisons great,

(40:15):
So they just constantly cook and eat delicious food, and
the like the big boss of the mafia in it
prepares sauces by slicing garlic with a razor blade, and
he sliced. They talk about how he slices it so
thin it would just liquefy in the pan. Alright, So
in this case though, of course we're not We're not
slicing garlic. We're sliding slicing infected ants. So they repeat

(40:37):
this slice and dice number some two thousand times over
a twenty four hour period. And along the way they're
capturing images of each slice, and that's with the scanning
electron microscope, so that's giving you incredibly detailed images of
very small stuff. Then they're able to stack these images
to create a three D digital model of the ant

(40:58):
and This is where AI research is led by Danny Chin,
Professor of Computer Science and Engineering a University of Notre Dame,
inters the picture, busting out artificial intelligence and machine learning
algorithms to analyze the images. They basically train computers to
tell the difference between fungal and ant cells. Just see
how much of this organism is AUNT and how much

(41:20):
of it is invading fungus. You're gonna like the answer.
A lot of it is invading fungus. And there are
some illustrations. Robert will try to link some of the
illustrations on our landing page. Right, so if you want
to go to stuff to Blow your mind dot com,
check out the landing page. We'll link out to these.
These images are terrifying. So they're they're intramuscular pictures, right,

(41:42):
so you get to see the ants muscles inside it's
exoskeleton and they're just surrounded by these reaths of fungal cells. Yeah,
like just imagine like tiny tiny vines growing about round
every detail inside the muscle tissue. There's one picture we've
got here that's a three reconstruction of the ant uh

(42:02):
mandible adductor muscle, and it it looks like it's got
I hate to invoke my favorite. No, I don't hate to,
I love to. It's got a crab monster on it.
There's a yellow crab monster crawling on this muscle. And
what this actually is is just this huge collocation of
networked fungal cells. Yeah, so what what they basically discovered

(42:23):
here is that the fungal cells were present through virtually
all regions of the host ant's body in a way
that suggested they might be interconnected as well networked even
And what's more, the stuff was clustered just outside the brain,
but they didn't seem to be any in the brain,
which which makes you question a lot of these ideas
about about you know, brain control, mind control um within

(42:46):
the ant. I mean, that's almost the exact opposite of
what I would have thought. I would have thought that
you'd see most of these cells in the brain invading
the brain tissue or central nervous tissue to control the behavior.
I wouldn't expect to see it so much. And you know,
the legs and the mandibles and all that. Yeah, but again,
this is the Mona Lisa of mind control parasites. One

(43:06):
of the things that the the Young points out in
his article is that other brain parasites. Not only do
they get into the brain, but in some cases they
destroy the brain to change an organism's behavior or his
He points out a flat worm that quote forms a
carpet like layer over the brain of the California killie fish,
leaving the brain intact while forcing the fish to behave

(43:27):
radically and draw the attention of birds. So, yeah, this
is something entirely more complex going on, But it does
force us to reconsider the previous notion that this was
more of just a straight up mind control hijacking of
the brain. Now, certainly this isn't there. They're not saying
that there's not some reprogramming of behavior going on here.

(43:50):
Very well be happening chemically, right, right, there's some sort
of chemical process probably going on, But there's also this
network extending throughout the body. I mean, we keep saying
mind control. That's probably an unscientific term. I know I've
used it, and that's not quite the right. What we
should be saying, for scientific accuracy is behavior control, because

(44:11):
you know, who wants to say what the mind of
an ant is when possessed by this thing. Though we
might speculate a little bit on that in a second. Um.
But yeah, if it's not mind control, is it more
like body control? Yeah? So the uh, the interesting thing
about the brain here is that the research is a
hypothesized that the creature's captive brain essentially captive. Think about

(44:33):
that this network has has moved throughout the body, taken
over the body, and the brain is just preserved in
there like it's amigo brain cancer and a Lovecraft story.
But it's preserved so they can it can perform the
final act that is necessary, biting onto the vegetation and
then never letting go. Wow. Yeah, so it's what's what's worse,

(44:55):
the the parasitic organism that destroys your brain to control
your body, or the parasitic organism that holds off and says, no,
we're not done with you yet, we have one more
thing for you to do. This is one of those
findings that's so cool. I am afraid it's going to
be subject to the to the retraction in a year
or something, just because doesn't that always have happened? You know,

(45:16):
they're gonna put feathers on our dinosaur. No no, no, no,
like in a year, it will be like no, no, no,
really it is just chemical alteration of the brain and
they're they're not really controlling the muscles so directly. But
for now that this is glorious, and I hope I
hope it's true. I hope this is this is the
correct analysis. I have a wonderful quote from David Hughes
here again he's the Associate professor of professor of demology

(45:38):
and biology at Pinn State who's been doing um all
this wonderful research with this particular fungus, and he said
in the press release, we found that a high percentage
of the cells and a host were fungal cells. In essence,
these manipulated animals were a fungus in ant's clothing. So
that's a that's that's the quite a vision. So to

(46:01):
speculate about being inside the ant's mind if there are,
if there were such a thing. Yeah, as impossible as
it is to try and think as an aunt and
to imagine the ant's experience, Uh yeah, what would that
be like? Would it be like like you're locked inside
your body and your body is doing things and you're
I guess you're also like behaviorally you're modified as well,

(46:22):
you want to do these things? Uh, and yet you're
you're you're still able to think. I guess again, these
are this is all anthrop anthropomorphic complexity when we try and, uh,
imagine what an aunt thinks, but it is Oh man,
it's it's just so nightmarish. Fortunately, this could never happen
in a human being, right well, one would hope, not

(46:44):
outside of a video game, right yeah, you would hope.
And I think there's no good reason to think that
that a fungus like this could parasitize humans. But if
we just want to hint of that kind of creepiness,
let's try. Most parasites, it is true, have highly specified
life cycles where they're really closely associated with their host organism.

(47:05):
But OPHEO Court accepts, fungi have been documented performing amazing
quote host jumps, not just two different species, not just
two different arthropods, but even across literally kingdoms of life. Yeah,
uh so. A two thousand study in the Journal of
Molecular Biology and Evolution by Naru Niko and Tacama Fukatsu

(47:30):
found that though most species of back then they were
calling it, Court accepts fungus, and though most of these
were adapted to arthropod hosts like insects and spiders and
so forth. At the time, about twenty of the known
three hundred species were parasitic not to arthropods, but to
hearts truffles. Truffles truffle mushrooms like hearts truffles are are

(47:54):
fungi of the genus Alapa mices huh So. Using phylogenetic analysis,
they discovered that the parasites of the heart struffles were
originally long ago parasites of Cicada nymphs. Quote. The common
habitats of Cicada nymps and hearts hearts truffles, deep underground

(48:16):
and associated with tree roots suggests that the inter kingdom
host jumping from animalia to fungi may have been promoted
by the overlapping ecological niche of the unrelated hosts. I mean,
this is so crazy. This is like if someone came
to you and they said, hey, there's something wrong with
one of the ferns that I'm growing in my home.

(48:38):
What's wrong with your ferns? It has tape worms, Like
you would just say no, no, no, that's impossible. Tape
We know where tape worms reside. They are not They're
not going to jump over into another kingdom. Entirely and
start wreaking. Have it there. Yeah, you normally wouldn't see
things like this because a parasite needs to be specified
to its host, like how would he how would it
even work in a body as different from an ant says, say,

(49:01):
like a mammal's. So you really hopefully don't have to
expect anything like that happening. But man, this is it
is a creepiness. Yeah, it's an example where where naturally
throws you for a curve here, just illustrating what is possible.
Um and yeah, so let that let the nightmares fly,
I guess, but but don't become too paranoid over it.

(49:23):
I will say, there's one thing working in our favor,
which is that I read that the Opheo coortcepts fungus
itself is subject to fungal parasitism. So there is a
hyper parasite, which is the name for a parasite that parasitizes.
A parasite hyper parasite fungus that attacks Ophio corticeps and

(49:43):
Ophio cortceps has to have defensive measures to protect itself
against this fungal parasite. Parasites within parasites within parasites it's
parasites all the way down, you know. As we we
close out here, I do want to mention another favorite
parasite of mine that is also an opio cortesceps opio
cortesceps sentences, which imagine people A number of our listeners

(50:08):
have run across this before, especially if you have visited
a Chinese apothecary shop or just traveled in the East
in general. I think this one used to just be
called cortesceps. Yeah, this is one where you find there's
there's been studied a lot. There are a lot of
papers on it, and most of the papers are a
little older and afford referred to it as cortesceps uh sentences.

(50:29):
It's native to the mountains of Tibetan Nepal, where it
parasitizes larva of ghost moths and produces a fruiting body
uh much like these other cortesceps we've discussed. It's often
described there as a route that's allegedly half vegetable and
half caterpillar, and it's exported as an energy booster and
an aphrodisiac. So according to Lonely Planet, the Tibetans call

(50:54):
it yartsa gumboo. Uh. But it's highly prized and traditional
Chinese medicine, where it's known as dong cheung zi choo
or winter worm summer grass, also known as the Himalayan viagra.
And you'll see it used in like a gen sing
like tonic, and the tonic is sometimes used to strengthen

(51:14):
the body or in the or using the treatment of
kidney and a lung problem. Now, there there are a
number of papers out there that look at the the
the the the alleged medical properties all of this or
this organism. I have not really researched it myself yet.
I haven't. I haven't dived into that particular area of
the research. So that's something we could come back to

(51:35):
at some point if we wanted to on the show. Yeah,
I wonder what potential there is. Yeah, it would be
interesting to tease it depart in the future for sure,
or to get inside it and erupt from the back
of its head. Yeah. So, speaking of which, I just
glanced over at our our producer Alex and uh, there
there is a small crack in the top of his
skull a and a fruiting body is beginning to emerge
from it. So I think that means we're out of time. Man,

(51:56):
Alex does good work. That's a talented parasite. Yeah, he
just works through it. He's committed, all right. Uh. In
the meantime, if you want to listen to other episodes
of Stuff to Blow Your Mind, heading over to stuff
to Blow your Mind dot com. That's our mothership. That's
where we'll find all the podcast episodes going back to
the beginning of time. You'll find blog post videos, links
out to our various social media accounts such as Facebook, Twitter, Tumbler, Instagram.

(52:19):
Facebook is where you'll find that lovely discussion module. It's
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the other listeners as well as your hosts. Oh and
if you want to support the show, a great way
to do it is to leave us a positive review,
give us stars or whatever the the the the rating
symbol happens to be at whatever system you used to

(52:40):
listen to the podcast. Yeah, give us a nice YELP review. Yes,
but hey, you can also get in touch with us
the old fashioned way. Oh, that's right, And we should
also mention you should check out the landing page for
today's episode, where we're gonna link to some images and
articles we referenced in the episode, But like he said,
if you want to get in touch with us by email,
blow the mind at how stuff works dot com for

(53:13):
more on this and thousands of other topics. Is it
how stuff works dot com.

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