February 11, 2025 • 62 mins
Okay everyone, think about your tongue. Maybe move it around a bit, check in with it, consider what it means to you. Now imagine that your tongue suddenly shriveled up and fell off and that in its place is a tongue-sized isopod aka rollie pollie aka pillbug. Just there, hanging out, forever. How are you feeling? Horrified? Disgusted? Hey, we get it. But at least you’ll never be alone again. Believe it or not, this is not some bad creative writing exercise. This is a very real parasite. In fact, it’s not just one but a whole group of them. Fortunately for us humans, these tongue-replacing isopods don’t target mammals but rather various fish species (unfortunately for the fish). And in this week’s episode, we’re getting up close and personal with these bizarre (and dare we say cute?) organ-replacing parasites. If you’re wondering why on earth you should care about a niche parasite like this one or why it might be a bad idea to get rid of all of earth’s parasites, then we warmly invite you to sit back, relax, and enjoy this parasite appreciation hour.
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
My name is doctor Jack Abrams. I'm a physician at
the Atlantic Hospital in Maryland. I'm making this video in
the hope that I will be able to watch it
at some point in the future, and I'm going to
show the world what happened here. I locked myself in
the ICU, the CDC stopped taking my phone calls, called FEMA.
Help hasn't arrived. I think I now know what is
(00:22):
killing people. We were looking for some kind of virus,
some kind of viral outbreak. I now know this is
not a virus. This is an organism. It is an
organism that has somehow infiltrated people's bodies. The blistering, that's
a symptom. That is what threw us off. It is
the isopod. It's eating their organs. It's literally eating them
(00:45):
from the inside. It is eating their intestines, it is
eating their liver. It goes for the kidneys, lungs, tissue.
This is a rapidly growing, accelerating organism. How it's growing
this fast, I have no idea. I noticed this rash
about forty five minutes ago, and I'm going to continue
to take the camera and I'm going to document everything
that I see here. If you find this tape, just
(01:08):
please get it out. Karin.
Speaker 2 (01:58):
It was so hard not to laugh. I loved I
loved your rendition of it. Clearly I am not an actor,
but I disagree with it. I disagree based on that beautiful.
Speaker 1 (02:11):
And that is my audition tape for The Bay too.
Speaker 2 (02:17):
You're hired.
Speaker 1 (02:18):
Yes, that magnificent piece of fiction is I pulled from
this incredible movie from twenty twelve called The Bay, which
really the creature at the heart of this episode is
also the creature at the heart of this creature feature film.
Speaker 2 (02:42):
Oh my goodness, it's amazing.
Speaker 3 (02:44):
Hi.
Speaker 2 (02:45):
I'm Aaron Welsh and I'm Eron Alman Updyke.
Speaker 3 (02:48):
And this is this podcast will kill you.
Speaker 2 (02:50):
It's a little different of an episode perhaps today it
really is.
Speaker 1 (02:55):
I think this is one of the first episodes where
we were just like, let's do this weird look thing
that we don't know anything about.
Speaker 2 (03:01):
There's got to be a story there. Yeah, and there is,
and a movie, a whole movie about it.
Speaker 3 (03:10):
Yeah.
Speaker 1 (03:11):
We are covering what is commonly known as the fish
tongue parasite.
Speaker 2 (03:17):
Right, or the fish eating laus tongue eating or tongue
eating lause not fish eating lause fish.
Speaker 1 (03:24):
I mean there are lice or well isopods, yes, marine
isopods that eat fish.
Speaker 3 (03:28):
Yeah, this is what they do.
Speaker 2 (03:31):
So it's a nicapod that we're talking about today. You've
probably have you seen the pictures. If you haven't, will
will you will?
Speaker 1 (03:37):
Yeah, by the end of this episode, it is an
adorable little isopod sticking out of the mouth of a
fish or it's like in there right where it's tongue
should be. That's because it has eaten the fish's tongue
and replaced it.
Speaker 4 (03:52):
We'll get into it a lot of it. And it's
organ replacing parasites. I mean, amazing. Yeah, there is a
lot of fun stuff to cover today, but first.
Speaker 2 (04:04):
It's quarantiny time.
Speaker 3 (04:06):
It is Aaron.
Speaker 2 (04:07):
What are we drinking this week? Well, we're drinking Laos
Got your Tongue? Yeah cause you know, we just said it.
We just said it.
Speaker 1 (04:14):
That's the name of it. Yes, Laos Got your Tongue.
It's your standard. My tie, which I'm shocked that we
haven't actually done before, but no we haven't. So in
your standard my tie is rum cursow orsia and lime juice.
Speaker 2 (04:30):
It's fantastic. Yeah. So delishous. So we'll push the full
recipe for that quarantini and the non alcoholic plasy Burta
on our website, this podcast, wiki dot com, and on
all of our social media channels. So make sure that
you're following us and you can see all the picks
and also videos of this recording that we do.
Speaker 3 (04:49):
Go now, yeah, we do do that.
Speaker 2 (04:51):
You can see Aaron's fish shirt by the way.
Speaker 3 (04:54):
Yes, minno madness. We's got sunglasses.
Speaker 2 (04:57):
It's a very cute fish. It's non effect.
Speaker 1 (05:00):
Did yeah I tell he's drinking what appears to be
a my tie could tie.
Speaker 3 (05:06):
That's pretty thrilling, yes, oh yeah.
Speaker 1 (05:10):
But also on our website you can find all sorts
of things from transcripts, you can find the resources that
we use to put together all of these episodes. You
can find links to bookshop dot org, affiliate account, our
Goodreads list, music by Bloodmobile, merch, some pretty sweet merch, Patreon,
a contact us form if you want to reach out
(05:32):
suggest an episode. You can invite us to give a talk.
We'd love that. You can ask us to do a workshop,
or you can say, hey, here's my first hand account.
There's a first hand account form for that. And other stuff.
There's so much stuff there.
Speaker 2 (05:46):
Yeah, well, shall we take a quick break and then
get into the creature feature of this week. Let's do it. So,
(06:30):
the creatures that we're discussing today are isopods, and I
thought we should start by what the heck is an isopod.
Speaker 3 (06:38):
It's a good starting point.
Speaker 2 (06:39):
Yeah. Isopods are crustaceans, which means that they're arthropods, so
they have exoskeletons that they shed between life stages in
order to grow. And these are more closely related to
like crabs and lobsters, which are also crustaceans they're decapods,
than they are to like bugs or insects, which are
(06:59):
of terrestrial arthropods. So the isopods that everyone listening is
probably most familiar with, whether you realized it or not,
are like roly polies, right or also known as woodlice,
also known as armadillo bugs, pill bugs. There's so many
colloquial names for these.
Speaker 3 (07:18):
Yeah, what did you grow up calling them roly polies too?
Speaker 2 (07:22):
Yeah, roly polis. I'm always curious where the different names are.
Speaker 3 (07:27):
I'm sure there's a map for that, Yeah.
Speaker 2 (07:29):
There probably is. What did you call them listeners. Roly polis,
I love that name.
Speaker 3 (07:34):
It's very cute.
Speaker 2 (07:36):
But so the roly polies are terrestrial isopods. Most isopods
are not terrestrial. Most of them are marine or freshwater dwelling.
There are probably at least ten thousand species of isopod
in the world, and they make their home everywhere across
the entire globe. And some of these isopods make their
(07:57):
homes inside of other creatures, meaning their parasites and parasitic
isopods come in a lot of different flavors, many of
which infect fish hosts. Fish are really phenomenal hosts for
so many parasites, and many isopods infect fish in a
(08:18):
whole bunch of different ways. Some of them might infect
fish externally, like attaching on near their eyeballs. Some of
them might attach in the guild chambers. Some of them
might even burrow their way like part way into their flesh.
And some live in the mouth holes of fish. And
(08:39):
that is the isopods, or those are the isopods that
we're focusing on today.
Speaker 5 (08:44):
Mouthhole mouth holes like mouth, yeah, mouth, Just wondering the
whole part at it, I mean, yeah, the whole the
whole hole they're in there, and there is not just
one of these so called tongue stealing parasites, No, no, no,
(09:06):
there are many.
Speaker 2 (09:07):
In fact, they primarily fall in the family Cymothoidae, and
within that family, there's a couple genera that seem the
most common to specifically do this tongue stealing thing. That
is the genus simo Thoa and Seratothoa, But there's several
other as well, and I think the phylogeny seems to
(09:29):
be influx. Yeah, the most famous of these, I think
the one that has gotten the most popular press is
Simothoa egg sigua. If that's how you pronounce it correctly.
Speaker 3 (09:40):
Your guess is as good as my, which is probably
not great.
Speaker 2 (09:44):
So we can use that species as an example since
it's maybe one of the most popular ones. But all
of these family of isopods share a pretty similar life cycle,
and we definitely don't know everything that there is to
know about these parasites, so there's a lot more that
we can learn, And because there's so many different species
(10:07):
which infect such a wide range of host fish, we're
gonna look really broad strokes at what their general life
cycle looks like to understand these parasites. So in general,
these baby simothoids when they're born, they're born as like
a live birth kind of because isopods have a brood
(10:29):
pouch that's called a marsupium, kind of like a kangaroo
or a koala. It's adorable, isn't it. And so they
hold their young, their eggs in this little pouch and
then they hatch, and then they develop through several little
life stages before they're ready to go off on their own.
So baby simothoids, which are also called manca or mank
(10:52):
that's the like baby form. Oh my god, I know
so many, so many weird names, like don't call them larva,
they're called wow okay. And once they leave their mothers,
they are free in the water, and they will first
attach to a host. Sometimes they might attach to a
(11:15):
host fish that they didn't mean to, like maybe not
the one that they really wanted. So then they might
take a few nibbles from somewhere on the fish and
then drop off. And eventually the point is to find
a suitable host. What species of fish that is will
depend on the species of isopod, but the goal is
(11:36):
to find a host that it's well adapted to which
is going to be some type of bony fish, and
once they do, they will attach to that final host.
Every single one of these isopods, these cymothoid isopods, is
born a male. So once they attach to their final
fish host, they will look around and if they're the
(11:58):
first ones there colonizing this host, they will change their
sex into a female.
Speaker 3 (12:05):
That's amazing.
Speaker 2 (12:06):
I know. It's called protandrius hermaphrodism, and it's a form
of what's called sequential hermaphrodism. So they're all born with
one sex and then some of them will go on
to change sexes over time, rather than simultaneous hermaphrodism, which
is something like snails which have both male and female
organs at the same time.
Speaker 3 (12:26):
Right, right, It's fascinating.
Speaker 2 (12:28):
But what this does is it allows for these isopods
to attach change if needed, into a female, and then
every other isopod that finds that same host will then
be a male that they'll be able to mate with
and then make eggs from there. Right.
Speaker 1 (12:43):
That's incredible because I kept seeing like the female isopods
are the ones that replace and I'm like, I wonder
why that is.
Speaker 2 (12:51):
But huh. It just means that she was the first
one to attach.
Speaker 3 (12:54):
Yeah wow.
Speaker 2 (12:56):
And then this isopod will live essentially the rest of
its entire life attached to that host, primarily eating their blood. Okay,
not eating scraps of whatever the fish is eating. Not
eating scraps of whatever the fish is eating. Some species,
because again we're talking about a pretty wide range of
(13:17):
different cymothoid isopods here. Some of them, it's thought maybe
feed more like on tissue in the fish's mouth, but
again it's feeding on the fish host itself, not on
what the fish is eating. But some have different mouthparts
that maybe look more like they're sucking pure blood versus
eating the fish tissue. But in any case, they're feeding
(13:40):
on the fish.
Speaker 3 (13:41):
And you said the rest of their lives? How long
is that?
Speaker 2 (13:45):
I knew that you were going to ask me that
questionnairein I don't know. Again, there's so many different species
for at least one of these, and the paper that
I found wasn't actually looking at one of these mouth
dwelling isopods, but it was a different simathoid isopod that
attaches near the eyeball of a fish. Those can live
(14:07):
for at least one year.
Speaker 3 (14:09):
Okay?
Speaker 2 (14:09):
Does that mean that they all can live at least
one year? Do any live longer? Who knows? Okay?
Speaker 1 (14:16):
So they spend the rest of their lives. At what
point then, do they like? So they are reproducing while
replacing the tongue, while acting as the tongue.
Speaker 2 (14:27):
While acting as the tongue. Okay, okay. So essentially it's
like this one isopod finds a fish. They are the
first ones there, so they're going to attach in the mouth.
For the ones that we're talking about today, they'll attach
in the mouth far back in the buckle cavity of
the fish, kind of near the gills, but not quite
(14:48):
near the gills, and then they will transform into their
final form, and in this case, if it's the first
one there, they'll transform into a female. That's the one
that's going to take up the whole mouth where they attach. Generally,
because they're feeding on blood. What it does is it
disrupts the blood flow to the fish's tongue to such
a degree that that fish tongue essentially begins to die.
(15:10):
And then this isopod is able to grow and fill
that entire buckle cavity, the entire mouth hole of that fish,
kind of replacing where that tongue used to be. Other
isopods will also find this fish and they will attach,
sometimes closer to the gills, sometimes just farther back in
(15:32):
that buckle cavity which again connects to the gills, because
that's how the fish is breathing. And those will remain
as males. The males are much smaller than the females,
so they'll be farther back and they won't get as big,
and they'll be able to mate, and then that female
will have that has that little brood pouch, so it's
just holding a bunch of little eggs that are growing
(15:53):
and then releasing as they're ready to do so today.
Speaker 3 (16:13):
Okay, so a couple questions.
Speaker 1 (16:16):
You said that, like finding the right host, I know
that a wide variety of fishes are affected or like
can be infested. I guess with this parasite and then
it will grow. So is its growth limited by the
size of the fish's mouth or do they find fish
(16:37):
that have a big enough mouth? Do they ever grow
so big that the fish can't actually feed?
Speaker 2 (16:42):
Aaron? I love you're such an ecologist.
Speaker 3 (16:48):
Thank you.
Speaker 2 (16:51):
These are all great questions where to begin. So, there
are a lot of different species of simothoids and they
can infect essentially like any fish that you imagine, they
probably there's probably a simothoid that could infect that fish.
(17:12):
Some of these species of isopod are more host specific
than others, and some are less host specific. Okay, the
question of like how big do they grow? Why do
some grow bigger and some grow some don't grow as large?
We don't really know, Like does that depend on just
(17:32):
who they ended up in? Is that part of why
there are strong host associations between some of these isopods
and some of their hosts.
Speaker 3 (17:41):
These are all really great questions.
Speaker 2 (17:43):
They're like evolutionary questions, they're like ecological questions because then
it's also like what is it doing to this fish?
So there's a lot to unpack there that we don't
fully know the answer to. Okay, so let's talk a
little bit more about like what this ends up up
looking like and what this ends up doing to the fish. Yeah. Yeah,
(18:06):
So first I want to talk about what this looks
like to give everyone like a mental image we're just
seeing like a tongue replacing what what if Google image
search it? But then also I'll describe it for you.
I also first want to say that a fish tongue
is different than our tongue, and this is important for
(18:27):
the idea that a fish could have their tongue replaced
in function by a parasite. Our tongue is this massive muscle, right,
So our tongue is really important in moving food around
in our mouth, pushing it from side to side. It's
also important in moving food to the back of our
throat so that we can actually engage our swallow reflex.
(18:50):
And we also use our tongue to speak to talk.
It's important in our breathing because it has to move
in certain ways. But a fish tongue is not like that.
A fish tongue doesn't have any skeletal muscle of its own.
It's just like a little meaty bit. It's not a muscle,
(19:13):
it's just flesh. What does it do. It's essentially a
mechanical device that just helps hold prey up against the
roof of the mouth so that the fish can do
whatever it needs to do, eat that prey and then
swallow it. But there's no muscle. But there's no muscle
to it. And if you look, if you google image,
there's a whole bunch of pictures of fish mouths without parasites.
(19:34):
Some of them don't even have that much of a
meaty tongue. Some just to have like this kind of
flat surface. Some have what almost look like teeth all
along the bottom like of their palate. So there's a
pretty wide variety of what a fish mouth might look like,
but they're none of them as complicated as like a
(19:56):
muscle that needs to be able to move around and
so well. The paper from nineteen eighty three by breusket
at All then first kind of proposed this hypothesis that
the isopod could functionally replace a fish's tongue kind of
really brought this to light, like it's not it makes
sense that this isopod could serve that same function because
(20:18):
it's not that.
Speaker 3 (20:19):
Hard if not anyone could do it.
Speaker 2 (20:22):
Like anyone could do it, an isopod could do it.
So what does it then look like when a parasite
is replacing a fish's tongue.
Speaker 3 (20:32):
It's frankly adorable. It is so adorable.
Speaker 1 (20:36):
So we might be outliers in this because when I
showed John, I was like, this, isn't this adorable?
Speaker 3 (20:43):
And he's like, is that the word is that? Is
that right?
Speaker 1 (20:47):
Is that the correct adjective? And I'm like, it certainly is.
Speaker 2 (20:51):
I know when I was describing it to Brett, he
was like visibly shook where he just was.
Speaker 1 (20:58):
Well, I think because we immediately put ourselves in the
position of having an isopod, a large isopod in our
mouths forever, which is.
Speaker 3 (21:09):
Not what happened in the bay, by the way, Oh
it's not.
Speaker 1 (21:12):
No, the tongues were gone and then they were Everyone
was eating from the inside out. You know, it's eating
the kidneys, it's eating the the livers.
Speaker 2 (21:18):
It seems much more intense than just the tongue.
Speaker 1 (21:21):
Yeah, I mean, there wasn't. It wasn't, let's say, the
most scientifically accurate movie.
Speaker 2 (21:26):
Oh. I'm really shocked to hear that.
Speaker 3 (21:28):
I enjoyed it though.
Speaker 2 (21:31):
Okay, So if you see a front on view of
like an open fish mouth that's infected with one of
these parasites, the first thing that you'll notice is a
pair of black eyes staring at you cut, and then
this little kind of almost triangular shaped head, it's like
a little bit round on top, and then a little
pointy little looks like a chin. Yeah, and then they
(21:54):
have what looked like almost little hands curled up under
their chin, like the way that a raccoon kind of
holds their across their chest. It's like, hi, hi there,
it's how it talks. Oh hi, I'm just making my
little home year its cave.
Speaker 3 (22:08):
Don't mind me.
Speaker 2 (22:09):
And then you can see what almost look like kind
of scales that disappear back into the fish's mouth. They're
not really scales, but isopods are arthropods, and so they
have segmented body parts like a shrimp or something. And
then these guys have seven pairs of these little leggy things.
They're called parapods, and they end in these pretty sharp
(22:31):
little hooks that they use to attach themselves to the fish. Ooh,
just like hook in there. If you were to look,
so that's what you see if you look straight on,
like aw in an open fish's mouth. If you were
looking at a fish in cross section, like you sliced
off the side of their cheek, and then you were
(22:52):
looking at what this isopod looked like, you would see
something that looks an awful lot like a roly poly.
It's white usually. And then based on most of the
pictures that I've seen and I haven't seen one of
these in real life, but they are usually quite a
bit bigger, depending on the species of fish that they're infecting,
(23:14):
than most roly pulleys in your yard. And they're a
little bit more flattened door so ventrally, so like tummy
to back. They're a little more flat so that they
can fit in their fish's little mouth there yea, And
this isopod essentially will take up like the entirety of
the fish's mouth, the female will at least, and then
sometimes if you do that cross section, you might see
(23:36):
one a smaller one further back, like almost halfway into
the gill cavity. And that is what it looks like
to be infected with one of these isopods.
Speaker 3 (23:46):
There are some amazing pictures out there.
Speaker 2 (23:50):
Really really incredible. If you're not following us on social media,
you'll have to Google search for yourself. You should just
follow us. We've posted the teachers. If you were wondering
when's the time, it's now.
Speaker 3 (24:02):
Okay.
Speaker 1 (24:03):
I have a question though about the effects, because we
basically said, okay, well, you know, it's a job so easy,
and I suppod could do it, as in replacing the tongue,
but it's not just replacing the tongue, it's also taking blood.
So are the fish negatively impacted by that aspect?
Speaker 2 (24:19):
That is a really important question. A lot of the
studies that have looked at what the effects are on
the fish that are infected are primarily in aquaculture settings
with farmed fish, which is logical because not only is
that a place where you can really study things like
survival and growth and length and all these things, but
also fish in aquaculture seem to be particularly susceptible to
(24:42):
infection with these parasites. Okay, I don't know exactly why.
It is thought that in aquaculture settings it's almost always
not a species that typically infects those fish, okay, and
they're introduced by wild fish that then come in contact
and then they're able to infect like the whole entire
(25:03):
aquacultureity NOx right. But there are also some really incredible, sound,
really difficult to do ecological studies that have looked at
these isopods in more natural settings. What are the effects
on like population dynamics even but also survival, reproduction. Long
story short overall, and again it varies specie to specie.
(25:26):
Diatata caveats. Fish that are infected with these tongue replacing
parasites do seem to be negatively affected to one degree
or another. We see things like anemia. We see evidence
of tissue damage and of the host's response to that
tissue damage, so things like inflammation where the parasite was attached.
(25:48):
We also can see inhibited growth and a reduction in
weight and length of fish that are infected versus not infected.
In some cases, we have increased mortality of infected fish
compared to non infected fish. And in a lot of
studies we see a reduction in egg production or in
egg quality in fish that are infected with a parasite
(26:09):
compared to not infected. Okay, so yeah, it's not great
for fish to have their tongue replaced by an isopod.
But Aaron, getting back to some of the questions that
you had asked about, like why does this isopod infect
the mouth? Like what is the strategy there? And then
like what are the trade offs between a mouth infection
(26:30):
versus an infection of an isopod somewhere else like on
the gills or on the external body or whatever. So
there was a really interesting paper I mentioned it already
by Brusk at All from nineteen eighty three, and that
was the first one that really was like, hey, this
isopod is essentially functionally replacing the tongue. The one that said, oh,
it's not that hard. And one of the things that
(26:51):
they pointed out that's really interesting is that by making
a niche in the mouth of this fish, the isopod
in a lot of cases can grow to a significantly
larger size than it could in say the gills of
a fish, because necessarily the size that that isopod grows
(27:15):
to essentially is displacing fish tissue. Right, it has to
like eat away a hole in the gills, which is
going to more negatively theoretically affect the fish if it
can't breathe as good. Then by replacing a space in
its mouth, that's already a potential space to inhabit, right, okay, okay,
(27:37):
And so that is one of the big ideas as
to how this relationship works. It allows for the females
to grow to a larger size, which theoretically means they
can hold more brood, so the isopods can reproduce more
readily or have greater fitness, and in the fish, it's
a relatively less negative impact. And they even said in
(27:59):
this which I thought was really interesting, that like, well
we think that, sure, maybe there's a negative impact for
an isopod to replace your tongue, but it's less negative
than just having your tongue eaten without anything to replace it.
Speaker 1 (28:13):
So that in itself is really interesting, isn't it.
Speaker 3 (28:16):
It's so so interesting.
Speaker 1 (28:19):
So these isopods essentially were preadapted to attached to a
fish host and consume tissue, and so there could have
been many different areas and it was like, oh, the
tail region not great, not a whole lot of tissue there.
Speaker 3 (28:37):
The fish can't swim, it's just going to sink and die.
Speaker 1 (28:40):
And that it's like what area is going to promote
longevity for both the fish and the isopod, And that
happens to be the mouth, Yeah, for these species.
Speaker 2 (28:49):
For these species, And like we know, biologist evolution doesn't
quite work like.
Speaker 3 (28:53):
That, but yes, right, And is a greater size always
a good thing? Not necessarily?
Speaker 2 (28:58):
Yeah, exactly right. Isn't that so interesting? Though? Arin?
Speaker 3 (29:02):
I just I love it.
Speaker 1 (29:04):
I just think these I think these little guys are
fascinating and fun and they've They've really been a parasite
that I have thought of ever since the day I
first saw them.
Speaker 2 (29:16):
They're one of your what Roman.
Speaker 3 (29:18):
Empires, Roman Empire? Yeah, one of my one of my
parasite Roman empires.
Speaker 2 (29:21):
Parasite Roman Empires. I mean yeah, same honestly, And like
every time I re remember them, I'm like, Wow, what
a thing to exist.
Speaker 3 (29:30):
I know, I'm glad that we did this deep dive.
Speaker 2 (29:35):
Yeah, well tell me speaking of deep dives, erin, I
have so many I don't know where to begin with
trying to understand the history of this, the evolution of this.
Speaker 1 (29:46):
The what yeah, yeah, yeah, let's just take a break
and then and then I'll begin. It probably won't come
(30:22):
as a tremendous shock that the history of the fish
tungue replacing isopod, specifically the species that I feel like
gets a lot of the press, the Simothoa exigua, That
history is a little thin. The history in general is
a little thin.
Speaker 2 (30:38):
Right, It's like, hey, we found this thing in nineteen
seventy nine, and.
Speaker 1 (30:43):
Well, yeah, I mean, I mean, and this this so
this genus of parasitic isopods actually goes back farther than
nineteen seventy nine, so Simothoa was described. Depending on who
you ask, it was either Linnaeus or Fabricius. And in
the late seventeen hundreds and then Simothoa Exigua got its
recognition or its name, I think in eighteen eighty four,
(31:06):
when two naturalists Sciote and mine Art included them in
a big monograph about the subject. I probably said those
names wrong, but nearly one hundred years would pass after
this monograph before anyone would pay significant attention to these
bizarre creatures. And in nineteen eighty one, in nineteen eighty three, Bruscat.
(31:28):
Like you said, Aaron, we've mentioned that these papers a
couple times published, first a monograph and then a paper.
The second paper, the eighty three paper, was with Gilligan
describing this isopod in detail and including some absolutely incredible
pictures with the isopod in the mouth of a fish,
the spotted rose snapper specifically. Also side note in this
(31:49):
paper is where I learned that there is a fish
species whose species name is boop, boops boops.
Speaker 2 (31:58):
Aaron, I almost I almost included that as a fun
fact too, because I loved it.
Speaker 3 (32:03):
I so loved it.
Speaker 1 (32:05):
I was like this can't be some type of seabream,
right boops boops?
Speaker 3 (32:09):
And I was like, what's a seabream?
Speaker 2 (32:10):
I don't know, but I love it.
Speaker 3 (32:14):
It's incredible.
Speaker 2 (32:15):
Yeah. Also, this episode made me feel really depressed about
how much knowledge your brain can just leech out because
I used to know so much about fish.
Speaker 1 (32:24):
Aaron Same, I took an ichthyology class in grad school.
I couldn't tell you anything.
Speaker 2 (32:30):
Same, I'm like, what's a how to relook up? Like
teleost Aaron.
Speaker 1 (32:35):
Yeah, I mean I'm married to a Phish biologist and
I still don't know very much.
Speaker 2 (32:39):
Listen, we all have our strengths.
Speaker 1 (32:41):
Yeah, But anyway, so since this nineteen eighty three paper,
researchers have mapped the general distribution of this critter and
other related critters.
Speaker 3 (32:52):
We've gained a better but incomplete.
Speaker 1 (32:54):
Understanding of its life cycle, and we've measured the impact
of these isopods on their fish hosts. But perhaps the
most exciting development in the history of this tongue eating
isopod is the twenty twelve movie The Bay, which is
where our first hand account came from. I really do
(33:14):
think that it like increased awareness of this parricide and
pollution in the Chesapeake Bay. I don't know. Maybe maybe
the Bay is a found footash and documenter. I just
I feel the need to include this because I watched
it last night, so you don't have to, like you,
meaning general audience, Aaron, I still want you to watch it.
Speaker 2 (33:35):
I am gonna watch it. Don't worry. I'm gonna watch
it tonight. I just felt didn't have time last night.
Speaker 1 (33:39):
Oh man, it is ridiculous, and I just it has
a shockingly high rating on rotten tomatoes seventy six percent,
and I'm I'm gonna I just want to read you
one more little quote from it, because how does it
have a seventy six percent?
Speaker 2 (33:56):
I want also all everyone listening to know how many
times I've heard Aaron say that it has seventy six.
Speaker 1 (34:01):
You could tell me that it has seventy six percent.
That's that's that's gonna be your Roman empire, is that
the Bay has a seventy six percent rating on rotten tomatoes. Okay,
here we go. I don't think we can rule out
a food borne virus or anything airborne, but this looks
like a water vector. The blistering looks like a kind
of cocosis. I don't know if that is spelt correctly
(34:23):
or anything, but that's how I wrote it down exactly.
From the subtitles. The lesions could be mycobacteria marinum or schistosomiasis.
I mean, Jesus, there could be cholera in there. If
the water's being polluted by anything chemical on top of
the bacteria, we could easily see a new form evolve,
maybe a fungal bacteria.
Speaker 3 (34:41):
What maybe a mutated tapeworm? Who knows?
Speaker 2 (34:45):
Ah. Oh, we would be so annoying for most people
to watch movies with.
Speaker 3 (34:52):
I think, Oh my gosh.
Speaker 1 (34:53):
I mean this is why when you and I watch
something together we drive other people away.
Speaker 3 (34:58):
Yes, yes, I love it.
Speaker 2 (35:04):
I mean a a fungal bacteria, mutated tapeworm? Why I know?
Speaker 3 (35:09):
What does that mean? A new form? A form?
Speaker 2 (35:14):
If that doesn't make someone want to watch this movie?
Speaker 1 (35:17):
Yeah, okay, but amazing movie aside, that's pretty much it.
When it comes to the history of these tongue eating isopods,
they haven't played a major role in World Wars. They
don't feature in the Hippocratic texts or ancient Egyptian papyri.
They aren't associated with any major developments in medicine. They
(35:39):
do have this incredible creature feature about them, which is
more than you could say for most parasites.
Speaker 3 (35:45):
I will give it that.
Speaker 2 (35:46):
True.
Speaker 1 (35:47):
True, but most people wouldn't place them high on a
list of quote unquote important parasites.
Speaker 2 (35:54):
True. Even amongst fish parasites, I couldn't find enough papers
that gave them the credit I feel like they.
Speaker 1 (36:01):
Deserve exactly, And to that I would say, yeah, most
people are wrong. Our human centric perspective prevents us from
grasping the significance of parasites and pathogens that don't directly
or even indirectly impact us, like livestock diseases. And even
if we do acknowledge the role that these underappreciated parasites
(36:24):
might play in an ecosystem, it's largely from a parasites
are bad and cause disease perspective. This is especially the
case when it comes to conservation, where parasites are more
often than not seen as a barrier to conservation efforts
rather than a focus of conservation itself.
Speaker 3 (36:45):
So if you think of any.
Speaker 1 (36:46):
Wildlife conservation program, what animals come to mind?
Speaker 2 (36:50):
Big like big charismatic mammals. Yes, I don't know.
Speaker 1 (36:55):
Big cats, big cats, giant pandas, elephants, polar bears, sperm whales,
these gorgeous and charismatic megafauna. You probably don't picture the
sperm whale roundworm that can grow up to nine meters
long nine meters nine meters.
Speaker 2 (37:16):
That's like when you said it, it actually like didn't
even register it because I was like, that doesn't it's
not wait can compute, Yeah, yeah, yep.
Speaker 1 (37:27):
Or you probably don't think of the protozoan parasite that
infects blackfooted ferrets, or the fish hung eating louse parasites
that would go extinct if their host went extinct.
Speaker 2 (37:38):
Like for example, the California condors lice, which did go extinct.
Speaker 3 (37:42):
Yes, I have it in here, I have that in
here as an example. Oh my gosh.
Speaker 1 (37:47):
Such seal conservation plans include directly ridding a target species
population of their parasites, so they choose one species over another.
They choose the free living organism over the parasitic species,
even if that means the extinction of that parasitic species.
Speaker 2 (38:05):
Right, because no one's worried about extinction of parasites.
Speaker 1 (38:08):
Exactly exactly, And maybe out there you're thinking, okay, but like,
what's the problem with that, like parasites cause disease, they
are bad, they're gross, Like why wouldn't we want a
parasite free world? And that's kind of what I want
to spend the rest of this history section talking about,
like why we should care about parasites, why they matter
(38:30):
in ecosystems, and why conserving parasite biodiversity rather than reducing it,
should be a goal of conservation programs.
Speaker 2 (38:38):
I love this so much. This is like such our roots.
Speaker 1 (38:42):
I know, I know who would have thought we found
our roots in the fish tongue eating laus parasite.
Speaker 2 (38:52):
And so maybe at.
Speaker 1 (38:53):
The end of this I won't have convinced you to
love and adore parasites, but at the very least I.
Speaker 2 (38:59):
Hope that I leave you with a little.
Speaker 1 (39:01):
Bit more appreciation for them. We're going to call this
the Parasite Appreciation Hour. Yes, yeah, this is a planet
of parasites. And I don't mean that in the sense
of like humans are parasites because we're exploiting all these
natural resources and destroying ecosystems and killing the planet, and
we are the parasites ourselves. You know that is true,
(39:21):
But I mean that on this planet parasites dominate. Parasitism
is the most common consumer strategy on this planet.
Speaker 2 (39:32):
Nobody Can you say that again, because nobody appreciates.
Speaker 1 (39:35):
That parasitism is the most common consumer strategy on this planet.
Parasites make up thirty to fifty percent or more of
all living species.
Speaker 2 (39:48):
That's a lot of species.
Speaker 3 (39:50):
It's a lot of species.
Speaker 1 (39:52):
They may be the most abundant and the most diverse
group of multicellular animals on Earth.
Speaker 2 (39:59):
I mean, and yet, and yet, and yet.
Speaker 1 (40:04):
Compared to free living organisms, they get a sliver of
the attention and the funding. In a twenty twenty paper
by Colin Carlson at all, one of my favorite authors
of scientific.
Speaker 3 (40:16):
Papers to read because they're just so.
Speaker 2 (40:18):
Quote from it is, ever from the same paper.
Speaker 3 (40:21):
It might be, it might be, it might be.
Speaker 1 (40:24):
Yeah, these so in this paper, the authors estimate that
there are between one hundred thousand and three hundred and
fifty thousand parasitic helmet species, the vast majority of which
eighty five to ninety five percent are still unknown. Oh
my gosh, hundreds of thousands of species unknown. Researchers who
(40:45):
study free living organisms massively outnumber those who study parasites.
I mean, and we can attest to this being like
the minority in our grad program of people who study
disease ecology or parasites at all, and many large scale
ecological survey programs like.
Speaker 3 (41:02):
NEON the National Environmental.
Speaker 1 (41:04):
Observatory Network barely make an effort to characterize the diversity
of parasites in an ecosystem, despite the fact that they
have been found in some communities to make up the
most biomass.
Speaker 2 (41:17):
I mean, where's the caring, Where's the caring?
Speaker 1 (41:21):
The bias against parasites is clear, but what is also
clear is there incredible importance in ecosystems. Conservation cost money,
and the goals of conservation programs sometimes conflict or appear
to conflict with the needs of a region or community
or the interests of a corporation. And so one big
(41:42):
challenge that conservation organizations face is justifying why conservation is important,
Like why should we invest time and resources into preserving
ecosystems and restoring biodiversity.
Speaker 2 (41:54):
What's it going to get us exactly.
Speaker 1 (41:57):
Especially if that comes at the cost of human eco
economic development. It goes without saying that this is a
complex issue and that the balance of trade offs or
even whether trade offs exist at all. Might be different
depending on who you ask and the timescale and landscape
scale that you're looking at, but the bottom line is
that conservation must be argued for and convincing people that
(42:21):
we need to conserve charismatic species like blue whales or
snow leopards that's one thing. But persuading them that wormy
parasites or parasites that replace the tongue of a fish
that we don't really think that much about, that these
are also worthy of conservation, that's a whole nother can
of worms pun intended. In their twenty twenty three paper
(42:45):
Conservation of Parasites a primer, authors Limbery and Smit lay
out three broad, not mutually exclusive categories that most pro
parasite conservation arguments fall into. So why should we conserve parasites?
Here are the three general categories. Number one intrinsic value.
Parasites are worthy of conservation because they are living things,
(43:05):
and like all living things, should be protected because all
of life has value. Number two, their ecological role. Parasites
are key species in all ecosystems and their removal could
have unforeseen or forcing and disastrous consequences. And number three
parasites can tell us how healthy or unhealthy an ecosystem is.
(43:29):
In other words, parasites are valuable number one because they
are number two because they are vital in ecosystems, and
number three because they are important to humans. These are
not the only reasons why parasites are important. For instance,
if we lose parasite diversity, we also lose opportunities to
study the incredibly varied ways these creatures have adapted to
(43:50):
this lifestyle, which could give us insights into the evolution
of novel traits, the transition from a parasitic to a
free living life cycle, and even the evolutionary history of
cir in host species, which we could assess by looking
at parasite genetic diversity. But for today, I want to
chat a bit more about just those three I mentioned,
and actually just two and three, because besides the true
(44:13):
parasite enthusiasts out there, I'm not sure a whole lot
of people are going to be convinced that parasites have
intrinsic value. As we learn in school and as Webster
Dictionary defines, a parasite is quote an organism living in
on or with another organism in order to obtain nutrients,
(44:34):
grow or multiply, often in a state that directly or
indirectly harms the host end quote. So why would something
that directly or indirectly harms another organism be valuable to
keep around the answer to that question comes down to
perspective and scale. To an individual elk infested with tapeworms,
(44:55):
that's not going to feel good.
Speaker 3 (44:56):
You're not going to like that.
Speaker 2 (44:58):
You're not like, yay more tape worm.
Speaker 3 (45:00):
Wow, this is wonderful. Love that.
Speaker 1 (45:02):
But to the wolves who can more easily take down
elk infested with tapeworms, that's great. And the fact that
not all elk in an ecosystem are infested with tapeworms
or have different parasite burdens. That introduces diversity into this dynamic,
influencing which elk survive and which don't and potentially driving
the evolution of this population. Parasites are well known to
(45:26):
mediate predator prey relationships like this.
Speaker 2 (45:29):
I love I love parasites and predator prayer relationships.
Speaker 1 (45:32):
They're just so good. There's so there's so much there.
It's just like life is trade offs. All of life
is trade offs, and it's all these interconnected tradeoffs and relationships,
and we don't understand it all and that's what I
love about it.
Speaker 2 (45:46):
Yeah. Also, there's just so many beautiful examples, including of
fish parasites that like, when you're infected with these parasites,
you're far more likely to get eaten by a bird,
and then that parasite is going to infect the bird,
and then it's just so.
Speaker 1 (46:00):
Good, it's so good. And then it's not just predator
prey relationships, right, Like, there's also competition among members of
a species. And so in these ways, parasites can affect
how energy and resources flow through an ecosystem. So take camel,
crickets and grasshoppers, which, when infected with a certain parasite quote,
(46:22):
are twenty times more likely to jump into a stream
where their biomass constitutes up to sixty percent of the
energy intake of endangered fish populations. WHOA, isn't that so cool?
Speaker 2 (46:36):
I love that?
Speaker 1 (46:37):
I know.
Speaker 2 (46:39):
Wow.
Speaker 1 (46:40):
The cascading effects of parasites in an ecosystem are difficult
to measure, but it's kind of like, as Joni Mitchell says,
you don't know what you got.
Speaker 3 (46:47):
Till it's gone.
Speaker 1 (46:51):
Parasite removal from an ecosystem is kind of like what
we saw with the removal of apex predators to protect livestock,
which led to an explosion in some populations, like some
herbivore populations, a decimation of others, and an overall vastly
changed landscape that regained stability once those apex predators like
(47:12):
wolves were reintroduced. Parasites play similar roles in ecosystems, helping
to organize, stabilize, and promote genetic diversity. Parasites can also
stimulate a host's immune system, so some studies have shown
that parasites can protect hosts from a novel pathogen or
damages from heavy metals.
Speaker 2 (47:31):
See our Allergies episode for more on that.
Speaker 1 (47:37):
Zoomed in to an individual level, it's very easy to
see why the word parasite has such negative connotations, but
taking in the big picture of an ecosystem, these are
vital and so underappreciated parts of this beautiful, intricate machine,
one where we don't fully understand how it runs and
what might happen.
Speaker 3 (47:57):
If we fiddle with this knob or adjust that level.
Speaker 1 (48:01):
And let me remind you again, this isn't a handful
of parasites playing an important role in a few interactions
here and there. Even though I've only given a few examples.
This is everywhere, This is everywhere. Free living organism on
this planet has parasites. Yeah again, Yeah, parasites might be
the most dominant life form on Earth period. And so
(48:22):
maybe you're still not fully convinced that we should conserve parasites.
I know you are, erin I had you at intrinsic value,
Yeah you did. But what if I told you that
we can use parasites to assess whether an ecosystem is
healthy or unhealthy. Certain species of parasites actually accumulate pollutants
more readily than their hosts, and so they can set
(48:44):
off early warning bells about a new pollutant or one
that's on the rise in a particular ecosystem, and parasites
with complex life cycles involving multiple hosts also tend to
be more sensitive to environmental change. So if humans alter
a habitat or introduced pollutants, or if the climate gets
warmer and drier, these parasites might be the first ones
(49:06):
to feel those changes, which can be helpful for us
to forecast potential downstream effects. Although it might seem like
a contradiction. A healthy ecosystem is one with parasites, not
one without. But as human mediated change keeps on trucking,
as this extinction crisis keeps on going, we're at risk
(49:27):
of losing this key component of ecosystem function. As a group,
parasites are among the most, if not the most overall
threatened with extinction, with estimates ranging from three to thirty
three percent at risk. Wow, because when a free living
species goes extinct, it takes with it it's species specific
(49:50):
parasites uniquely adapted to that species, and most of these
parasites have never been characterized in the first place, which
makes it that much ha harder to track their disappearance.
Most conservation aims don't specifically include parasites, and very very
few parasites are on any endangered species lists, which doesn't
(50:11):
mean that there aren't any endangered parasites, because there absolutely are.
What we need is a shift in how we perceive parasites.
We need to do a better job at recognizing their value,
characterizing their diversity, understanding their role in ecosystems, and developing
concrete goals for their conservation. And very importantly, let me
(50:34):
underline this, these goals are not preserve all parasites no
matter what, because I know some of you out there
are like, wait a second, I thought we were trying
to eradicate for cunculiasis caused by this parasitic worm.
Speaker 3 (50:48):
Should we save that?
Speaker 2 (50:50):
No?
Speaker 1 (50:50):
No, absolutely not. We are trying to eradicate for cunculiasis
and we will get there eventually. Shout out to Jimmy
Carter and the amazing work of the Carter Foundation. The
research groups that have put together these road maps for
parasite conservation make it very clear that there are exceptions.
No one is a parasite extremist. Parasites that are excluded
(51:11):
from these plans include those that present a disease risk
to human health, livestock health, or threaten the existence of
a wildlife species, like the nematode that infects giant pandas
and can actually lead to their death. So no, this
is not a call to save all the parasites, but
it is a call to acknowledge their incredible diversity and
(51:31):
underappreciated significance, and maybe just to reflect on our own
bias when it comes to parasites. Save the whales absolutely,
but also save the whale tapeworm, save the fish tongue
louse parasite. So with that eron, I'll get off my
soapbox and hand it over to you to tell us
(51:52):
what's going on in the world of fish tongue replacing
isopods today.
Speaker 2 (51:59):
We'll get it to it right after this break. Oh, Aaron,
(52:29):
that was so much fun to just think about parasites
in a much larger context. That's also where I will end,
but to bring it back for a moment to simothoid isipods, like,
what are.
Speaker 3 (52:46):
We talking about again?
Speaker 2 (52:48):
What are you? What's this episode about? One of the
things that I wanted to underscore here because I think
that these parasites, specifically Simothoa xi uh gets the most
attention as like the one. It is not the one.
There are so many of them. But I fall into
(53:09):
that trap too. I was like, Uh, this is the
one that I see the papers about. It's an understandable
trap to fall into. But there are so many of
these parasites which are mouth dwelling parasites, and they're literally
everywhere across the entire globe.
Speaker 3 (53:29):
In some studies that I found.
Speaker 2 (53:31):
That we're looking at, you know, like specific species of
this particular isopod in specific species of fish. Right, so
like one paper on this species, another paper on this
species across the board. In some of these prevalents of
these parasites was as high as like forty five percent.
Speaker 3 (53:50):
That's so high, I know.
Speaker 2 (53:53):
And it does seem to vary depending on the size
of the fish. So smaller fish prevalence seems to be
higher in a lot of k and less prevalence in
the larger fish. Why is that, I don't know. Is
it this once they get larger, has the isopod already died?
I don't have an answer for that. But it also
varies geographically. Though these isopods are present across the entire globe,
(54:17):
they do seem to be at higher prevalence in warmer
tropical waters as well as in places where we have
a lot of aquaculture, because in some studies they have
found prevalence of these fish tungue parasites in aquaculture that
are as high as like ninety eight percent. And there
have been some cases of like relatively high rates of
(54:39):
mortality in aquaculture species of fish. And that's not usually
due to a typical host parasite interaction, but maybe like
a parasite that doesn't typically infect that species of fish.
So there's not like a general conclusion that I can
draw from all of this, because there's so many different
space ease of these parasites that infect so many different
(55:03):
species of fish.
Speaker 1 (55:05):
Aaron, what about geographic range, Like are these parasite species
sort of distributed globally across the world or they increase
in prevalence or incidents or diversity as you get closer
to the equator.
Speaker 2 (55:21):
That's a good question. I didn't look at whether you
have like an increase in diversity with latitude and stuff
like that. I would assume similar to a lot of
other parasite and you know species in general, that you
probably see higher diversity in tropical areas that are warmer,
et cetera. A lot of the papers that tried to
look at like overall diversity of these parasites were very
(55:43):
region specific. So we have papers that are like, here's
the diversity in the Indian Ocean, here's the diversity in
this region, here's the diversity around Australia, and stuff like that.
So I didn't find any that were, well, there was
a couple actually that was like global diversity, but they're
just like really really broad and also don't tend to
be specific to just the tongue replacing simothoids, but are
(56:05):
looking at simothoids more broadly, because again, these can also
infect fish in other areas, not just in their tongue.
In any case, there's a lot of them. They're everywhere.
So where do we go from here?
Speaker 4 (56:22):
Right?
Speaker 2 (56:23):
There's so many open questions how many species are there?
Speaker 3 (56:27):
Really?
Speaker 2 (56:28):
Because we don't know are they changing in distribution? Like
are they moving around? And if so, why, what is
it that's driving changes in distribution? Why is it that
some species are much more host specific than others. What
are the factors they're driving this host specificity? I don't know,
so many questions.
Speaker 3 (56:47):
There are so many questions.
Speaker 2 (56:50):
Uh, and so I don't have answers to any of
those questions. There are so many people doing work to
better understand the natural history, the other the ecology of
these parasites. But I also wanted to end this episode
with some bits from I think the same paper.
Speaker 3 (57:11):
I have three Colin Carlson papers.
Speaker 1 (57:13):
So yeah, well, although it's not just it's not just Carlson.
Speaker 2 (57:18):
No Colin Carlson at all, A longtime friend of the
pod I've decided we're friends never met. But this was
the paper from twenty twenty that was published in Proceedings
of the Royal Society B and I just really appreciated
this paper not only for its thoroughness. It was like
(57:39):
a really long, detailed paper that essentially makes the case
for a real need to get a handle on the
existence of parasite diversity across the globe. And this paper
uses worms, mostly worms that do infect humans, as a
case study in this and it also goes into a
(58:01):
lot of detail on like how does one how do
we as a scientific community go about actually accomplishing this
and what does it mean for understanding our planet and
the health of our planet both now and of course
under conditions of climate change in the future. And so
I just want to I don't have profound things to
(58:25):
say as conclusion of this paper, but like, I just
do think that it's so this parasite, which is charismatic
in its own way right.
Speaker 3 (58:35):
More than other parasites, if we are allowed to be.
Speaker 2 (58:38):
The judge, yes, much more than other parasites, because it
is very cute, It is very startling, like it makes
you feel things, even if those things aren't like the
warm and fuzzies. I think that it gives us the
opportunity to really think about parasites in a way that
(58:58):
most people just don't ever think about parasites, or try
not to think about parasites. And so I want to
end with this one little quote from this paper. Quote.
Though some consider the task of cataloging parasite diversity a
testimony to human inquisitiveness, it is also a critical baseline
(59:19):
for understanding biological interactions in a world on the brink
of ecological collapse. End quote. And I feel like that's
an important thing to keep in mind. Parasites have a
lot that they can teach us, and we should learn
from them. Yeah, agreed, case case closed, not taking questions, thank.
Speaker 3 (59:43):
You, goodbye comments only.
Speaker 2 (59:46):
But we have lots of places that you can learn
more about these parasites. The simathoidiopods so cute and kill
so many other parasites and their roles in our ecosystem.
So let's say it with some.
Speaker 3 (59:58):
Sources, so so many sources.
Speaker 1 (01:00:01):
Arin, Okay, So I will shout out once again that
Bruska and Gilligan paper from nineteen eighty three that has
a great description of one of these parasites, and then
when it comes to the importance of parasites in ecosystems
and why we should conserve parasites. I have a million papers.
I really enjoyed one by Limberry and Smit from twenty
(01:00:22):
twenty three titled Conservation of Parasites A Primer, which I
also shouted out in the history section. But there are
so many ones out there that are not reviews but
like specific papers about this parasite in this ecosystem or
in this population, and it's just honestly really enlightening reading.
Speaker 2 (01:00:40):
I love it. I have a number of papers, more
than I expected for this episode. I also loved that
Brusken Gilligan paper. There was one from nineteen ninety eight
by Bunkley, Williams and Williams called Isopods associated with Fishes,
A Synopsis and Corrections, And then a one I really
love from twenty fourteen by Smit at all Global Diversity
(01:01:03):
of Fish Parasitic isopod Crustaceans of the family Simothoida. So
there's a few other papers that are more broadly about
the simothoids, and then a bunch of like specific ones
about this species versus that species et cetera. But as always,
we'll post the full list of our sources from this
episode and every single one of our episodes on our website,
This podcast will kill You dot Com. Check it out.
Speaker 3 (01:01:25):
Thank you to Bloodmobile for providing the music for this
episode and all.
Speaker 2 (01:01:29):
Of our episodes. Thank you to the film director of
the Bay Just Kidding. A thank you to Tom Bryfocal
and Leona Schoolatchi for the audio mixing.
Speaker 3 (01:01:39):
Thank you to everyone at Exactly Right.
Speaker 2 (01:01:41):
And thank you to you listeners. We hope that you
enjoyed this episode. We hope you love parasites a little
bit more than you did before. Yeah, and we hope
you learned something new and.
Speaker 1 (01:01:52):
A special thank you and shout out as always to
our fantastic patrons.
Speaker 3 (01:01:56):
Your support means the world.
Speaker 2 (01:01:57):
To us, it really does. Thank you. Well.
Speaker 3 (01:02:01):
Until next time, wash your hands
Speaker 2 (01:02:03):
You feel the animals
My name is doctor Jack Abrams. I'm a physician at
the Atlantic Hospital in Maryland. I'm making this video in
the hope that I will be able to watch it
at some point in the future, and I'm going to
show the world what happened here. I locked myself in
the ICU, the CDC stopped taking my phone calls, called FEMA.
Help hasn't arrived. I think I now know what is
(00:22):
killing people. We were looking for some kind of virus,
some kind of viral outbreak. I now know this is
not a virus. This is an organism. It is an
organism that has somehow infiltrated people's bodies. The blistering, that's
a symptom. That is what threw us off. It is
the isopod. It's eating their organs. It's literally eating them
(00:45):
from the inside. It is eating their intestines, it is
eating their liver. It goes for the kidneys, lungs, tissue.
This is a rapidly growing, accelerating organism. How it's growing
this fast, I have no idea. I noticed this rash
about forty five minutes ago, and I'm going to continue
to take the camera and I'm going to document everything
that I see here. If you find this tape, just
(01:08):
please get it out. Karin.
Speaker 2 (01:58):
It was so hard not to laugh. I loved I
loved your rendition of it. Clearly I am not an actor,
but I disagree with it. I disagree based on that beautiful.
Speaker 1 (02:11):
And that is my audition tape for The Bay too.
Speaker 2 (02:17):
You're hired.
Speaker 1 (02:18):
Yes, that magnificent piece of fiction is I pulled from
this incredible movie from twenty twelve called The Bay, which
really the creature at the heart of this episode is
also the creature at the heart of this creature feature film.
Speaker 2 (02:42):
Oh my goodness, it's amazing.
Speaker 3 (02:44):
Hi.
Speaker 2 (02:45):
I'm Aaron Welsh and I'm Eron Alman Updyke.
Speaker 3 (02:48):
And this is this podcast will kill you.
Speaker 2 (02:50):
It's a little different of an episode perhaps today it
really is.
Speaker 1 (02:55):
I think this is one of the first episodes where
we were just like, let's do this weird look thing
that we don't know anything about.
Speaker 2 (03:01):
There's got to be a story there. Yeah, and there is,
and a movie, a whole movie about it.
Speaker 3 (03:10):
Yeah.
Speaker 1 (03:11):
We are covering what is commonly known as the fish
tongue parasite.
Speaker 2 (03:17):
Right, or the fish eating laus tongue eating or tongue
eating lause not fish eating lause fish.
Speaker 1 (03:24):
I mean there are lice or well isopods, yes, marine
isopods that eat fish.
Speaker 3 (03:28):
Yeah, this is what they do.
Speaker 2 (03:31):
So it's a nicapod that we're talking about today. You've
probably have you seen the pictures. If you haven't, will
will you will?
Speaker 1 (03:37):
Yeah, by the end of this episode, it is an
adorable little isopod sticking out of the mouth of a
fish or it's like in there right where it's tongue
should be. That's because it has eaten the fish's tongue
and replaced it.
Speaker 4 (03:52):
We'll get into it a lot of it. And it's
organ replacing parasites. I mean, amazing. Yeah, there is a
lot of fun stuff to cover today, but first.
Speaker 2 (04:04):
It's quarantiny time.
Speaker 3 (04:06):
It is Aaron.
Speaker 2 (04:07):
What are we drinking this week? Well, we're drinking Laos
Got your Tongue? Yeah cause you know, we just said it.
We just said it.
Speaker 1 (04:14):
That's the name of it. Yes, Laos Got your Tongue.
It's your standard. My tie, which I'm shocked that we
haven't actually done before, but no we haven't. So in
your standard my tie is rum cursow orsia and lime juice.
Speaker 2 (04:30):
It's fantastic. Yeah. So delishous. So we'll push the full
recipe for that quarantini and the non alcoholic plasy Burta
on our website, this podcast, wiki dot com, and on
all of our social media channels. So make sure that
you're following us and you can see all the picks
and also videos of this recording that we do.
Speaker 3 (04:49):
Go now, yeah, we do do that.
Speaker 2 (04:51):
You can see Aaron's fish shirt by the way.
Speaker 3 (04:54):
Yes, minno madness. We's got sunglasses.
Speaker 2 (04:57):
It's a very cute fish. It's non effect.
Speaker 1 (05:00):
Did yeah I tell he's drinking what appears to be
a my tie could tie.
Speaker 3 (05:06):
That's pretty thrilling, yes, oh yeah.
Speaker 1 (05:10):
But also on our website you can find all sorts
of things from transcripts, you can find the resources that
we use to put together all of these episodes. You
can find links to bookshop dot org, affiliate account, our
Goodreads list, music by Bloodmobile, merch, some pretty sweet merch, Patreon,
a contact us form if you want to reach out
(05:32):
suggest an episode. You can invite us to give a talk.
We'd love that. You can ask us to do a workshop,
or you can say, hey, here's my first hand account.
There's a first hand account form for that. And other stuff.
There's so much stuff there.
Speaker 2 (05:46):
Yeah, well, shall we take a quick break and then
get into the creature feature of this week. Let's do it. So,
(06:30):
the creatures that we're discussing today are isopods, and I
thought we should start by what the heck is an isopod.
Speaker 3 (06:38):
It's a good starting point.
Speaker 2 (06:39):
Yeah. Isopods are crustaceans, which means that they're arthropods, so
they have exoskeletons that they shed between life stages in
order to grow. And these are more closely related to
like crabs and lobsters, which are also crustaceans they're decapods,
than they are to like bugs or insects, which are
(06:59):
of terrestrial arthropods. So the isopods that everyone listening is
probably most familiar with, whether you realized it or not,
are like roly polies, right or also known as woodlice,
also known as armadillo bugs, pill bugs. There's so many
colloquial names for these.
Speaker 3 (07:18):
Yeah, what did you grow up calling them roly polies too?
Speaker 2 (07:22):
Yeah, roly polis. I'm always curious where the different names are.
Speaker 3 (07:27):
I'm sure there's a map for that, Yeah.
Speaker 2 (07:29):
There probably is. What did you call them listeners. Roly polis,
I love that name.
Speaker 3 (07:34):
It's very cute.
Speaker 2 (07:36):
But so the roly polies are terrestrial isopods. Most isopods
are not terrestrial. Most of them are marine or freshwater dwelling.
There are probably at least ten thousand species of isopod
in the world, and they make their home everywhere across
the entire globe. And some of these isopods make their
(07:57):
homes inside of other creatures, meaning their parasites and parasitic
isopods come in a lot of different flavors, many of
which infect fish hosts. Fish are really phenomenal hosts for
so many parasites, and many isopods infect fish in a
(08:18):
whole bunch of different ways. Some of them might infect
fish externally, like attaching on near their eyeballs. Some of
them might attach in the guild chambers. Some of them
might even burrow their way like part way into their flesh.
And some live in the mouth holes of fish. And
(08:39):
that is the isopods, or those are the isopods that
we're focusing on today.
Speaker 5 (08:44):
Mouthhole mouth holes like mouth, yeah, mouth, Just wondering the
whole part at it, I mean, yeah, the whole the
whole hole they're in there, and there is not just
one of these so called tongue stealing parasites, No, no, no,
(09:06):
there are many.
Speaker 2 (09:07):
In fact, they primarily fall in the family Cymothoidae, and
within that family, there's a couple genera that seem the
most common to specifically do this tongue stealing thing. That
is the genus simo Thoa and Seratothoa, But there's several
other as well, and I think the phylogeny seems to
(09:29):
be influx. Yeah, the most famous of these, I think
the one that has gotten the most popular press is
Simothoa egg sigua. If that's how you pronounce it correctly.
Speaker 3 (09:40):
Your guess is as good as my, which is probably
not great.
Speaker 2 (09:44):
So we can use that species as an example since
it's maybe one of the most popular ones. But all
of these family of isopods share a pretty similar life cycle,
and we definitely don't know everything that there is to
know about these parasites, so there's a lot more that
we can learn, And because there's so many different species
(10:07):
which infect such a wide range of host fish, we're
gonna look really broad strokes at what their general life
cycle looks like to understand these parasites. So in general,
these baby simothoids when they're born, they're born as like
a live birth kind of because isopods have a brood
(10:29):
pouch that's called a marsupium, kind of like a kangaroo
or a koala. It's adorable, isn't it. And so they
hold their young, their eggs in this little pouch and
then they hatch, and then they develop through several little
life stages before they're ready to go off on their own.
So baby simothoids, which are also called manca or mank
(10:52):
that's the like baby form. Oh my god, I know
so many, so many weird names, like don't call them larva,
they're called wow okay. And once they leave their mothers,
they are free in the water, and they will first
attach to a host. Sometimes they might attach to a
(11:15):
host fish that they didn't mean to, like maybe not
the one that they really wanted. So then they might
take a few nibbles from somewhere on the fish and
then drop off. And eventually the point is to find
a suitable host. What species of fish that is will
depend on the species of isopod, but the goal is
(11:36):
to find a host that it's well adapted to which
is going to be some type of bony fish, and
once they do, they will attach to that final host.
Every single one of these isopods, these cymothoid isopods, is
born a male. So once they attach to their final
fish host, they will look around and if they're the
(11:58):
first ones there colonizing this host, they will change their
sex into a female.
Speaker 3 (12:05):
That's amazing.
Speaker 2 (12:06):
I know. It's called protandrius hermaphrodism, and it's a form
of what's called sequential hermaphrodism. So they're all born with
one sex and then some of them will go on
to change sexes over time, rather than simultaneous hermaphrodism, which
is something like snails which have both male and female
organs at the same time.
Speaker 3 (12:26):
Right, right, It's fascinating.
Speaker 2 (12:28):
But what this does is it allows for these isopods
to attach change if needed, into a female, and then
every other isopod that finds that same host will then
be a male that they'll be able to mate with
and then make eggs from there. Right.
Speaker 1 (12:43):
That's incredible because I kept seeing like the female isopods
are the ones that replace and I'm like, I wonder
why that is.
Speaker 2 (12:51):
But huh. It just means that she was the first
one to attach.
Speaker 3 (12:54):
Yeah wow.
Speaker 2 (12:56):
And then this isopod will live essentially the rest of
its entire life attached to that host, primarily eating their blood. Okay,
not eating scraps of whatever the fish is eating. Not
eating scraps of whatever the fish is eating. Some species,
because again we're talking about a pretty wide range of
(13:17):
different cymothoid isopods here. Some of them, it's thought maybe
feed more like on tissue in the fish's mouth, but
again it's feeding on the fish host itself, not on
what the fish is eating. But some have different mouthparts
that maybe look more like they're sucking pure blood versus
eating the fish tissue. But in any case, they're feeding
(13:40):
on the fish.
Speaker 3 (13:41):
And you said the rest of their lives? How long
is that?
Speaker 2 (13:45):
I knew that you were going to ask me that
questionnairein I don't know. Again, there's so many different species
for at least one of these, and the paper that
I found wasn't actually looking at one of these mouth
dwelling isopods, but it was a different simathoid isopod that
attaches near the eyeball of a fish. Those can live
(14:07):
for at least one year.
Speaker 3 (14:09):
Okay?
Speaker 2 (14:09):
Does that mean that they all can live at least
one year? Do any live longer? Who knows? Okay?
Speaker 1 (14:16):
So they spend the rest of their lives. At what
point then, do they like? So they are reproducing while
replacing the tongue, while acting as the tongue.
Speaker 2 (14:27):
While acting as the tongue. Okay, okay. So essentially it's
like this one isopod finds a fish. They are the
first ones there, so they're going to attach in the mouth.
For the ones that we're talking about today, they'll attach
in the mouth far back in the buckle cavity of
the fish, kind of near the gills, but not quite
(14:48):
near the gills, and then they will transform into their
final form, and in this case, if it's the first
one there, they'll transform into a female. That's the one
that's going to take up the whole mouth where they attach. Generally,
because they're feeding on blood. What it does is it
disrupts the blood flow to the fish's tongue to such
a degree that that fish tongue essentially begins to die.
(15:10):
And then this isopod is able to grow and fill
that entire buckle cavity, the entire mouth hole of that fish,
kind of replacing where that tongue used to be. Other
isopods will also find this fish and they will attach,
sometimes closer to the gills, sometimes just farther back in
(15:32):
that buckle cavity which again connects to the gills, because
that's how the fish is breathing. And those will remain
as males. The males are much smaller than the females,
so they'll be farther back and they won't get as big,
and they'll be able to mate, and then that female
will have that has that little brood pouch, so it's
just holding a bunch of little eggs that are growing
(15:53):
and then releasing as they're ready to do so today.
Speaker 3 (16:13):
Okay, so a couple questions.
Speaker 1 (16:16):
You said that, like finding the right host, I know
that a wide variety of fishes are affected or like
can be infested. I guess with this parasite and then
it will grow. So is its growth limited by the
size of the fish's mouth or do they find fish
(16:37):
that have a big enough mouth? Do they ever grow
so big that the fish can't actually feed?
Speaker 2 (16:42):
Aaron? I love you're such an ecologist.
Speaker 3 (16:48):
Thank you.
Speaker 2 (16:51):
These are all great questions where to begin. So, there
are a lot of different species of simothoids and they
can infect essentially like any fish that you imagine, they
probably there's probably a simothoid that could infect that fish.
(17:12):
Some of these species of isopod are more host specific
than others, and some are less host specific. Okay, the
question of like how big do they grow? Why do
some grow bigger and some grow some don't grow as large?
We don't really know, Like does that depend on just
(17:32):
who they ended up in? Is that part of why
there are strong host associations between some of these isopods
and some of their hosts.
Speaker 3 (17:41):
These are all really great questions.
Speaker 2 (17:43):
They're like evolutionary questions, they're like ecological questions because then
it's also like what is it doing to this fish?
So there's a lot to unpack there that we don't
fully know the answer to. Okay, so let's talk a
little bit more about like what this ends up up
looking like and what this ends up doing to the fish. Yeah. Yeah,
(18:06):
So first I want to talk about what this looks
like to give everyone like a mental image we're just
seeing like a tongue replacing what what if Google image
search it? But then also I'll describe it for you.
I also first want to say that a fish tongue
is different than our tongue, and this is important for
(18:27):
the idea that a fish could have their tongue replaced
in function by a parasite. Our tongue is this massive muscle, right,
So our tongue is really important in moving food around
in our mouth, pushing it from side to side. It's
also important in moving food to the back of our
throat so that we can actually engage our swallow reflex.
(18:50):
And we also use our tongue to speak to talk.
It's important in our breathing because it has to move
in certain ways. But a fish tongue is not like that.
A fish tongue doesn't have any skeletal muscle of its own.
It's just like a little meaty bit. It's not a muscle,
(19:13):
it's just flesh. What does it do. It's essentially a
mechanical device that just helps hold prey up against the
roof of the mouth so that the fish can do
whatever it needs to do, eat that prey and then
swallow it. But there's no muscle. But there's no muscle
to it. And if you look, if you google image,
there's a whole bunch of pictures of fish mouths without parasites.
(19:34):
Some of them don't even have that much of a
meaty tongue. Some just to have like this kind of
flat surface. Some have what almost look like teeth all
along the bottom like of their palate. So there's a
pretty wide variety of what a fish mouth might look like,
but they're none of them as complicated as like a
(19:56):
muscle that needs to be able to move around and
so well. The paper from nineteen eighty three by breusket
at All then first kind of proposed this hypothesis that
the isopod could functionally replace a fish's tongue kind of
really brought this to light, like it's not it makes
sense that this isopod could serve that same function because
(20:18):
it's not that.
Speaker 3 (20:19):
Hard if not anyone could do it.
Speaker 2 (20:22):
Like anyone could do it, an isopod could do it.
So what does it then look like when a parasite
is replacing a fish's tongue.
Speaker 3 (20:32):
It's frankly adorable. It is so adorable.
Speaker 1 (20:36):
So we might be outliers in this because when I
showed John, I was like, this, isn't this adorable?
Speaker 3 (20:43):
And he's like, is that the word is that? Is
that right?
Speaker 1 (20:47):
Is that the correct adjective? And I'm like, it certainly is.
Speaker 2 (20:51):
I know when I was describing it to Brett, he
was like visibly shook where he just was.
Speaker 1 (20:58):
Well, I think because we immediately put ourselves in the
position of having an isopod, a large isopod in our
mouths forever, which is.
Speaker 3 (21:09):
Not what happened in the bay, by the way, Oh
it's not.
Speaker 1 (21:12):
No, the tongues were gone and then they were Everyone
was eating from the inside out. You know, it's eating
the kidneys, it's eating the the livers.
Speaker 2 (21:18):
It seems much more intense than just the tongue.
Speaker 1 (21:21):
Yeah, I mean, there wasn't. It wasn't, let's say, the
most scientifically accurate movie.
Speaker 2 (21:26):
Oh. I'm really shocked to hear that.
Speaker 3 (21:28):
I enjoyed it though.
Speaker 2 (21:31):
Okay, So if you see a front on view of
like an open fish mouth that's infected with one of
these parasites, the first thing that you'll notice is a
pair of black eyes staring at you cut, and then
this little kind of almost triangular shaped head, it's like
a little bit round on top, and then a little
pointy little looks like a chin. Yeah, and then they
(21:54):
have what looked like almost little hands curled up under
their chin, like the way that a raccoon kind of
holds their across their chest. It's like, hi, hi there,
it's how it talks. Oh hi, I'm just making my
little home year its cave.
Speaker 3 (22:08):
Don't mind me.
Speaker 2 (22:09):
And then you can see what almost look like kind
of scales that disappear back into the fish's mouth. They're
not really scales, but isopods are arthropods, and so they
have segmented body parts like a shrimp or something. And
then these guys have seven pairs of these little leggy things.
They're called parapods, and they end in these pretty sharp
(22:31):
little hooks that they use to attach themselves to the fish. Ooh,
just like hook in there. If you were to look,
so that's what you see if you look straight on,
like aw in an open fish's mouth. If you were
looking at a fish in cross section, like you sliced
off the side of their cheek, and then you were
(22:52):
looking at what this isopod looked like, you would see
something that looks an awful lot like a roly poly.
It's white usually. And then based on most of the
pictures that I've seen and I haven't seen one of
these in real life, but they are usually quite a
bit bigger, depending on the species of fish that they're infecting,
(23:14):
than most roly pulleys in your yard. And they're a
little bit more flattened door so ventrally, so like tummy
to back. They're a little more flat so that they
can fit in their fish's little mouth there yea, And
this isopod essentially will take up like the entirety of
the fish's mouth, the female will at least, and then
sometimes if you do that cross section, you might see
(23:36):
one a smaller one further back, like almost halfway into
the gill cavity. And that is what it looks like
to be infected with one of these isopods.
Speaker 3 (23:46):
There are some amazing pictures out there.
Speaker 2 (23:50):
Really really incredible. If you're not following us on social media,
you'll have to Google search for yourself. You should just
follow us. We've posted the teachers. If you were wondering
when's the time, it's now.
Speaker 3 (24:02):
Okay.
Speaker 1 (24:03):
I have a question though about the effects, because we
basically said, okay, well, you know, it's a job so easy,
and I suppod could do it, as in replacing the tongue,
but it's not just replacing the tongue, it's also taking blood.
So are the fish negatively impacted by that aspect?
Speaker 2 (24:19):
That is a really important question. A lot of the
studies that have looked at what the effects are on
the fish that are infected are primarily in aquaculture settings
with farmed fish, which is logical because not only is
that a place where you can really study things like
survival and growth and length and all these things, but
also fish in aquaculture seem to be particularly susceptible to
(24:42):
infection with these parasites. Okay, I don't know exactly why.
It is thought that in aquaculture settings it's almost always
not a species that typically infects those fish, okay, and
they're introduced by wild fish that then come in contact
and then they're able to infect like the whole entire
(25:03):
aquacultureity NOx right. But there are also some really incredible, sound,
really difficult to do ecological studies that have looked at
these isopods in more natural settings. What are the effects
on like population dynamics even but also survival, reproduction. Long
story short overall, and again it varies specie to specie.
(25:26):
Diatata caveats. Fish that are infected with these tongue replacing
parasites do seem to be negatively affected to one degree
or another. We see things like anemia. We see evidence
of tissue damage and of the host's response to that
tissue damage, so things like inflammation where the parasite was attached.
(25:48):
We also can see inhibited growth and a reduction in
weight and length of fish that are infected versus not infected.
In some cases, we have increased mortality of infected fish
compared to non infected fish. And in a lot of
studies we see a reduction in egg production or in
egg quality in fish that are infected with a parasite
(26:09):
compared to not infected. Okay, so yeah, it's not great
for fish to have their tongue replaced by an isopod.
But Aaron, getting back to some of the questions that
you had asked about, like why does this isopod infect
the mouth? Like what is the strategy there? And then
like what are the trade offs between a mouth infection
(26:30):
versus an infection of an isopod somewhere else like on
the gills or on the external body or whatever. So
there was a really interesting paper I mentioned it already
by Brusk at All from nineteen eighty three, and that
was the first one that really was like, hey, this
isopod is essentially functionally replacing the tongue. The one that said, oh,
it's not that hard. And one of the things that
(26:51):
they pointed out that's really interesting is that by making
a niche in the mouth of this fish, the isopod
in a lot of cases can grow to a significantly
larger size than it could in say the gills of
a fish, because necessarily the size that that isopod grows
(27:15):
to essentially is displacing fish tissue. Right, it has to
like eat away a hole in the gills, which is
going to more negatively theoretically affect the fish if it
can't breathe as good. Then by replacing a space in
its mouth, that's already a potential space to inhabit, right, okay, okay,
(27:37):
And so that is one of the big ideas as
to how this relationship works. It allows for the females
to grow to a larger size, which theoretically means they
can hold more brood, so the isopods can reproduce more
readily or have greater fitness, and in the fish, it's
a relatively less negative impact. And they even said in
(27:59):
this which I thought was really interesting, that like, well
we think that, sure, maybe there's a negative impact for
an isopod to replace your tongue, but it's less negative
than just having your tongue eaten without anything to replace it.
Speaker 1 (28:13):
So that in itself is really interesting, isn't it.
Speaker 3 (28:16):
It's so so interesting.
Speaker 1 (28:19):
So these isopods essentially were preadapted to attached to a
fish host and consume tissue, and so there could have
been many different areas and it was like, oh, the
tail region not great, not a whole lot of tissue there.
Speaker 3 (28:37):
The fish can't swim, it's just going to sink and die.
Speaker 1 (28:40):
And that it's like what area is going to promote
longevity for both the fish and the isopod, And that
happens to be the mouth, Yeah, for these species.
Speaker 2 (28:49):
For these species, And like we know, biologist evolution doesn't
quite work like.
Speaker 3 (28:53):
That, but yes, right, And is a greater size always
a good thing? Not necessarily?
Speaker 2 (28:58):
Yeah, exactly right. Isn't that so interesting? Though? Arin?
Speaker 3 (29:02):
I just I love it.
Speaker 1 (29:04):
I just think these I think these little guys are
fascinating and fun and they've They've really been a parasite
that I have thought of ever since the day I
first saw them.
Speaker 2 (29:16):
They're one of your what Roman.
Speaker 3 (29:18):
Empires, Roman Empire? Yeah, one of my one of my
parasite Roman empires.
Speaker 2 (29:21):
Parasite Roman Empires. I mean yeah, same honestly, And like
every time I re remember them, I'm like, Wow, what
a thing to exist.
Speaker 3 (29:30):
I know, I'm glad that we did this deep dive.
Speaker 2 (29:35):
Yeah, well tell me speaking of deep dives, erin, I
have so many I don't know where to begin with
trying to understand the history of this, the evolution of this.
Speaker 1 (29:46):
The what yeah, yeah, yeah, let's just take a break
and then and then I'll begin. It probably won't come
(30:22):
as a tremendous shock that the history of the fish
tungue replacing isopod, specifically the species that I feel like
gets a lot of the press, the Simothoa exigua, That
history is a little thin. The history in general is
a little thin.
Speaker 2 (30:38):
Right, It's like, hey, we found this thing in nineteen
seventy nine, and.
Speaker 1 (30:43):
Well, yeah, I mean, I mean, and this this so
this genus of parasitic isopods actually goes back farther than
nineteen seventy nine, so Simothoa was described. Depending on who
you ask, it was either Linnaeus or Fabricius. And in
the late seventeen hundreds and then Simothoa Exigua got its
recognition or its name, I think in eighteen eighty four,
(31:06):
when two naturalists Sciote and mine Art included them in
a big monograph about the subject. I probably said those
names wrong, but nearly one hundred years would pass after
this monograph before anyone would pay significant attention to these
bizarre creatures. And in nineteen eighty one, in nineteen eighty three, Bruscat.
(31:28):
Like you said, Aaron, we've mentioned that these papers a
couple times published, first a monograph and then a paper.
The second paper, the eighty three paper, was with Gilligan
describing this isopod in detail and including some absolutely incredible
pictures with the isopod in the mouth of a fish,
the spotted rose snapper specifically. Also side note in this
(31:49):
paper is where I learned that there is a fish
species whose species name is boop, boops boops.
Speaker 2 (31:58):
Aaron, I almost I almost included that as a fun
fact too, because I loved it.
Speaker 3 (32:03):
I so loved it.
Speaker 1 (32:05):
I was like this can't be some type of seabream,
right boops boops?
Speaker 3 (32:09):
And I was like, what's a seabream?
Speaker 2 (32:10):
I don't know, but I love it.
Speaker 3 (32:14):
It's incredible.
Speaker 2 (32:15):
Yeah. Also, this episode made me feel really depressed about
how much knowledge your brain can just leech out because
I used to know so much about fish.
Speaker 1 (32:24):
Aaron Same, I took an ichthyology class in grad school.
I couldn't tell you anything.
Speaker 2 (32:30):
Same, I'm like, what's a how to relook up? Like
teleost Aaron.
Speaker 1 (32:35):
Yeah, I mean I'm married to a Phish biologist and
I still don't know very much.
Speaker 2 (32:39):
Listen, we all have our strengths.
Speaker 1 (32:41):
Yeah, But anyway, so since this nineteen eighty three paper,
researchers have mapped the general distribution of this critter and
other related critters.
Speaker 3 (32:52):
We've gained a better but incomplete.
Speaker 1 (32:54):
Understanding of its life cycle, and we've measured the impact
of these isopods on their fish hosts. But perhaps the
most exciting development in the history of this tongue eating
isopod is the twenty twelve movie The Bay, which is
where our first hand account came from. I really do
(33:14):
think that it like increased awareness of this parricide and
pollution in the Chesapeake Bay. I don't know. Maybe maybe
the Bay is a found footash and documenter. I just
I feel the need to include this because I watched
it last night, so you don't have to, like you,
meaning general audience, Aaron, I still want you to watch it.
Speaker 2 (33:35):
I am gonna watch it. Don't worry. I'm gonna watch
it tonight. I just felt didn't have time last night.
Speaker 1 (33:39):
Oh man, it is ridiculous, and I just it has
a shockingly high rating on rotten tomatoes seventy six percent,
and I'm I'm gonna I just want to read you
one more little quote from it, because how does it
have a seventy six percent?
Speaker 2 (33:56):
I want also all everyone listening to know how many
times I've heard Aaron say that it has seventy six.
Speaker 1 (34:01):
You could tell me that it has seventy six percent.
That's that's that's gonna be your Roman empire, is that
the Bay has a seventy six percent rating on rotten tomatoes. Okay,
here we go. I don't think we can rule out
a food borne virus or anything airborne, but this looks
like a water vector. The blistering looks like a kind
of cocosis. I don't know if that is spelt correctly
(34:23):
or anything, but that's how I wrote it down exactly.
From the subtitles. The lesions could be mycobacteria marinum or schistosomiasis.
I mean, Jesus, there could be cholera in there. If
the water's being polluted by anything chemical on top of
the bacteria, we could easily see a new form evolve,
maybe a fungal bacteria.
Speaker 3 (34:41):
What maybe a mutated tapeworm? Who knows?
Speaker 2 (34:45):
Ah. Oh, we would be so annoying for most people
to watch movies with.
Speaker 3 (34:52):
I think, Oh my gosh.
Speaker 1 (34:53):
I mean this is why when you and I watch
something together we drive other people away.
Speaker 3 (34:58):
Yes, yes, I love it.
Speaker 2 (35:04):
I mean a a fungal bacteria, mutated tapeworm? Why I know?
Speaker 3 (35:09):
What does that mean? A new form? A form?
Speaker 2 (35:14):
If that doesn't make someone want to watch this movie?
Speaker 1 (35:17):
Yeah, okay, but amazing movie aside, that's pretty much it.
When it comes to the history of these tongue eating isopods,
they haven't played a major role in World Wars. They
don't feature in the Hippocratic texts or ancient Egyptian papyri.
They aren't associated with any major developments in medicine. They
(35:39):
do have this incredible creature feature about them, which is
more than you could say for most parasites.
Speaker 3 (35:45):
I will give it that.
Speaker 2 (35:46):
True.
Speaker 1 (35:47):
True, but most people wouldn't place them high on a
list of quote unquote important parasites.
Speaker 2 (35:54):
True. Even amongst fish parasites, I couldn't find enough papers
that gave them the credit I feel like they.
Speaker 1 (36:01):
Deserve exactly, And to that I would say, yeah, most
people are wrong. Our human centric perspective prevents us from
grasping the significance of parasites and pathogens that don't directly
or even indirectly impact us, like livestock diseases. And even
if we do acknowledge the role that these underappreciated parasites
(36:24):
might play in an ecosystem, it's largely from a parasites
are bad and cause disease perspective. This is especially the
case when it comes to conservation, where parasites are more
often than not seen as a barrier to conservation efforts
rather than a focus of conservation itself.
Speaker 3 (36:45):
So if you think of any.
Speaker 1 (36:46):
Wildlife conservation program, what animals come to mind?
Speaker 2 (36:50):
Big like big charismatic mammals. Yes, I don't know.
Speaker 1 (36:55):
Big cats, big cats, giant pandas, elephants, polar bears, sperm whales,
these gorgeous and charismatic megafauna. You probably don't picture the
sperm whale roundworm that can grow up to nine meters
long nine meters nine meters.
Speaker 2 (37:16):
That's like when you said it, it actually like didn't
even register it because I was like, that doesn't it's
not wait can compute, Yeah, yeah, yep.
Speaker 1 (37:27):
Or you probably don't think of the protozoan parasite that
infects blackfooted ferrets, or the fish hung eating louse parasites
that would go extinct if their host went extinct.
Speaker 2 (37:38):
Like for example, the California condors lice, which did go extinct.
Speaker 3 (37:42):
Yes, I have it in here, I have that in
here as an example. Oh my gosh.
Speaker 1 (37:47):
Such seal conservation plans include directly ridding a target species
population of their parasites, so they choose one species over another.
They choose the free living organism over the parasitic species,
even if that means the extinction of that parasitic species.
Speaker 2 (38:05):
Right, because no one's worried about extinction of parasites.
Speaker 1 (38:08):
Exactly exactly, And maybe out there you're thinking, okay, but like,
what's the problem with that, like parasites cause disease, they
are bad, they're gross, Like why wouldn't we want a
parasite free world? And that's kind of what I want
to spend the rest of this history section talking about,
like why we should care about parasites, why they matter
(38:30):
in ecosystems, and why conserving parasite biodiversity rather than reducing it,
should be a goal of conservation programs.
Speaker 2 (38:38):
I love this so much. This is like such our roots.
Speaker 1 (38:42):
I know, I know who would have thought we found
our roots in the fish tongue eating laus parasite.
Speaker 2 (38:52):
And so maybe at.
Speaker 1 (38:53):
The end of this I won't have convinced you to
love and adore parasites, but at the very least I.
Speaker 2 (38:59):
Hope that I leave you with a little.
Speaker 1 (39:01):
Bit more appreciation for them. We're going to call this
the Parasite Appreciation Hour. Yes, yeah, this is a planet
of parasites. And I don't mean that in the sense
of like humans are parasites because we're exploiting all these
natural resources and destroying ecosystems and killing the planet, and
we are the parasites ourselves. You know that is true,
(39:21):
But I mean that on this planet parasites dominate. Parasitism
is the most common consumer strategy on this planet.
Speaker 2 (39:32):
Nobody Can you say that again, because nobody appreciates.
Speaker 1 (39:35):
That parasitism is the most common consumer strategy on this planet.
Parasites make up thirty to fifty percent or more of
all living species.
Speaker 2 (39:48):
That's a lot of species.
Speaker 3 (39:50):
It's a lot of species.
Speaker 1 (39:52):
They may be the most abundant and the most diverse
group of multicellular animals on Earth.
Speaker 2 (39:59):
I mean, and yet, and yet, and yet.
Speaker 1 (40:04):
Compared to free living organisms, they get a sliver of
the attention and the funding. In a twenty twenty paper
by Colin Carlson at all, one of my favorite authors
of scientific.
Speaker 3 (40:16):
Papers to read because they're just so.
Speaker 2 (40:18):
Quote from it is, ever from the same paper.
Speaker 3 (40:21):
It might be, it might be, it might be.
Speaker 1 (40:24):
Yeah, these so in this paper, the authors estimate that
there are between one hundred thousand and three hundred and
fifty thousand parasitic helmet species, the vast majority of which
eighty five to ninety five percent are still unknown. Oh
my gosh, hundreds of thousands of species unknown. Researchers who
(40:45):
study free living organisms massively outnumber those who study parasites.
I mean, and we can attest to this being like
the minority in our grad program of people who study
disease ecology or parasites at all, and many large scale
ecological survey programs like.
Speaker 3 (41:02):
NEON the National Environmental.
Speaker 1 (41:04):
Observatory Network barely make an effort to characterize the diversity
of parasites in an ecosystem, despite the fact that they
have been found in some communities to make up the
most biomass.
Speaker 2 (41:17):
I mean, where's the caring, Where's the caring?
Speaker 1 (41:21):
The bias against parasites is clear, but what is also
clear is there incredible importance in ecosystems. Conservation cost money,
and the goals of conservation programs sometimes conflict or appear
to conflict with the needs of a region or community
or the interests of a corporation. And so one big
(41:42):
challenge that conservation organizations face is justifying why conservation is important,
Like why should we invest time and resources into preserving
ecosystems and restoring biodiversity.
Speaker 2 (41:54):
What's it going to get us exactly.
Speaker 1 (41:57):
Especially if that comes at the cost of human eco
economic development. It goes without saying that this is a
complex issue and that the balance of trade offs or
even whether trade offs exist at all. Might be different
depending on who you ask and the timescale and landscape
scale that you're looking at, but the bottom line is
that conservation must be argued for and convincing people that
(42:21):
we need to conserve charismatic species like blue whales or
snow leopards that's one thing. But persuading them that wormy
parasites or parasites that replace the tongue of a fish
that we don't really think that much about, that these
are also worthy of conservation, that's a whole nother can
of worms pun intended. In their twenty twenty three paper
(42:45):
Conservation of Parasites a primer, authors Limbery and Smit lay
out three broad, not mutually exclusive categories that most pro
parasite conservation arguments fall into. So why should we conserve parasites?
Here are the three general categories. Number one intrinsic value.
Parasites are worthy of conservation because they are living things,
(43:05):
and like all living things, should be protected because all
of life has value. Number two, their ecological role. Parasites
are key species in all ecosystems and their removal could
have unforeseen or forcing and disastrous consequences. And number three
parasites can tell us how healthy or unhealthy an ecosystem is.
(43:29):
In other words, parasites are valuable number one because they
are number two because they are vital in ecosystems, and
number three because they are important to humans. These are
not the only reasons why parasites are important. For instance,
if we lose parasite diversity, we also lose opportunities to
study the incredibly varied ways these creatures have adapted to
(43:50):
this lifestyle, which could give us insights into the evolution
of novel traits, the transition from a parasitic to a
free living life cycle, and even the evolutionary history of
cir in host species, which we could assess by looking
at parasite genetic diversity. But for today, I want to
chat a bit more about just those three I mentioned,
and actually just two and three, because besides the true
(44:13):
parasite enthusiasts out there, I'm not sure a whole lot
of people are going to be convinced that parasites have
intrinsic value. As we learn in school and as Webster
Dictionary defines, a parasite is quote an organism living in
on or with another organism in order to obtain nutrients,
(44:34):
grow or multiply, often in a state that directly or
indirectly harms the host end quote. So why would something
that directly or indirectly harms another organism be valuable to
keep around the answer to that question comes down to
perspective and scale. To an individual elk infested with tapeworms,
(44:55):
that's not going to feel good.
Speaker 3 (44:56):
You're not going to like that.
Speaker 2 (44:58):
You're not like, yay more tape worm.
Speaker 3 (45:00):
Wow, this is wonderful. Love that.
Speaker 1 (45:02):
But to the wolves who can more easily take down
elk infested with tapeworms, that's great. And the fact that
not all elk in an ecosystem are infested with tapeworms
or have different parasite burdens. That introduces diversity into this dynamic,
influencing which elk survive and which don't and potentially driving
the evolution of this population. Parasites are well known to
(45:26):
mediate predator prey relationships like this.
Speaker 2 (45:29):
I love I love parasites and predator prayer relationships.
Speaker 1 (45:32):
They're just so good. There's so there's so much there.
It's just like life is trade offs. All of life
is trade offs, and it's all these interconnected tradeoffs and relationships,
and we don't understand it all and that's what I
love about it.
Speaker 2 (45:46):
Yeah. Also, there's just so many beautiful examples, including of
fish parasites that like, when you're infected with these parasites,
you're far more likely to get eaten by a bird,
and then that parasite is going to infect the bird,
and then it's just so.
Speaker 1 (46:00):
Good, it's so good. And then it's not just predator
prey relationships, right, Like, there's also competition among members of
a species. And so in these ways, parasites can affect
how energy and resources flow through an ecosystem. So take camel,
crickets and grasshoppers, which, when infected with a certain parasite quote,
(46:22):
are twenty times more likely to jump into a stream
where their biomass constitutes up to sixty percent of the
energy intake of endangered fish populations. WHOA, isn't that so cool?
Speaker 2 (46:36):
I love that?
Speaker 1 (46:37):
I know.
Speaker 2 (46:39):
Wow.
Speaker 1 (46:40):
The cascading effects of parasites in an ecosystem are difficult
to measure, but it's kind of like, as Joni Mitchell says,
you don't know what you got.
Speaker 3 (46:47):
Till it's gone.
Speaker 1 (46:51):
Parasite removal from an ecosystem is kind of like what
we saw with the removal of apex predators to protect livestock,
which led to an explosion in some populations, like some
herbivore populations, a decimation of others, and an overall vastly
changed landscape that regained stability once those apex predators like
(47:12):
wolves were reintroduced. Parasites play similar roles in ecosystems, helping
to organize, stabilize, and promote genetic diversity. Parasites can also
stimulate a host's immune system, so some studies have shown
that parasites can protect hosts from a novel pathogen or
damages from heavy metals.
Speaker 2 (47:31):
See our Allergies episode for more on that.
Speaker 1 (47:37):
Zoomed in to an individual level, it's very easy to
see why the word parasite has such negative connotations, but
taking in the big picture of an ecosystem, these are
vital and so underappreciated parts of this beautiful, intricate machine,
one where we don't fully understand how it runs and
what might happen.
Speaker 3 (47:57):
If we fiddle with this knob or adjust that level.
Speaker 1 (48:01):
And let me remind you again, this isn't a handful
of parasites playing an important role in a few interactions
here and there. Even though I've only given a few examples.
This is everywhere, This is everywhere. Free living organism on
this planet has parasites. Yeah again, Yeah, parasites might be
the most dominant life form on Earth period. And so
(48:22):
maybe you're still not fully convinced that we should conserve parasites.
I know you are, erin I had you at intrinsic value,
Yeah you did. But what if I told you that
we can use parasites to assess whether an ecosystem is
healthy or unhealthy. Certain species of parasites actually accumulate pollutants
more readily than their hosts, and so they can set
(48:44):
off early warning bells about a new pollutant or one
that's on the rise in a particular ecosystem, and parasites
with complex life cycles involving multiple hosts also tend to
be more sensitive to environmental change. So if humans alter
a habitat or introduced pollutants, or if the climate gets
warmer and drier, these parasites might be the first ones
(49:06):
to feel those changes, which can be helpful for us
to forecast potential downstream effects. Although it might seem like
a contradiction. A healthy ecosystem is one with parasites, not
one without. But as human mediated change keeps on trucking,
as this extinction crisis keeps on going, we're at risk
(49:27):
of losing this key component of ecosystem function. As a group,
parasites are among the most, if not the most overall
threatened with extinction, with estimates ranging from three to thirty
three percent at risk. Wow, because when a free living
species goes extinct, it takes with it it's species specific
(49:50):
parasites uniquely adapted to that species, and most of these
parasites have never been characterized in the first place, which
makes it that much ha harder to track their disappearance.
Most conservation aims don't specifically include parasites, and very very
few parasites are on any endangered species lists, which doesn't
(50:11):
mean that there aren't any endangered parasites, because there absolutely are.
What we need is a shift in how we perceive parasites.
We need to do a better job at recognizing their value,
characterizing their diversity, understanding their role in ecosystems, and developing
concrete goals for their conservation. And very importantly, let me
(50:34):
underline this, these goals are not preserve all parasites no
matter what, because I know some of you out there
are like, wait a second, I thought we were trying
to eradicate for cunculiasis caused by this parasitic worm.
Speaker 3 (50:48):
Should we save that?
Speaker 2 (50:50):
No?
Speaker 1 (50:50):
No, absolutely not. We are trying to eradicate for cunculiasis
and we will get there eventually. Shout out to Jimmy
Carter and the amazing work of the Carter Foundation. The
research groups that have put together these road maps for
parasite conservation make it very clear that there are exceptions.
No one is a parasite extremist. Parasites that are excluded
(51:11):
from these plans include those that present a disease risk
to human health, livestock health, or threaten the existence of
a wildlife species, like the nematode that infects giant pandas
and can actually lead to their death. So no, this
is not a call to save all the parasites, but
it is a call to acknowledge their incredible diversity and
(51:31):
underappreciated significance, and maybe just to reflect on our own
bias when it comes to parasites. Save the whales absolutely,
but also save the whale tapeworm, save the fish tongue
louse parasite. So with that eron, I'll get off my
soapbox and hand it over to you to tell us
(51:52):
what's going on in the world of fish tongue replacing
isopods today.
Speaker 2 (51:59):
We'll get it to it right after this break. Oh, Aaron,
(52:29):
that was so much fun to just think about parasites
in a much larger context. That's also where I will end,
but to bring it back for a moment to simothoid isipods, like,
what are.
Speaker 3 (52:46):
We talking about again?
Speaker 2 (52:48):
What are you? What's this episode about? One of the
things that I wanted to underscore here because I think
that these parasites, specifically Simothoa xi uh gets the most
attention as like the one. It is not the one.
There are so many of them. But I fall into
(53:09):
that trap too. I was like, Uh, this is the
one that I see the papers about. It's an understandable
trap to fall into. But there are so many of
these parasites which are mouth dwelling parasites, and they're literally
everywhere across the entire globe.
Speaker 3 (53:29):
In some studies that I found.
Speaker 2 (53:31):
That we're looking at, you know, like specific species of
this particular isopod in specific species of fish. Right, so
like one paper on this species, another paper on this
species across the board. In some of these prevalents of
these parasites was as high as like forty five percent.
Speaker 3 (53:50):
That's so high, I know.
Speaker 2 (53:53):
And it does seem to vary depending on the size
of the fish. So smaller fish prevalence seems to be
higher in a lot of k and less prevalence in
the larger fish. Why is that, I don't know. Is
it this once they get larger, has the isopod already died?
I don't have an answer for that. But it also
varies geographically. Though these isopods are present across the entire globe,
(54:17):
they do seem to be at higher prevalence in warmer
tropical waters as well as in places where we have
a lot of aquaculture, because in some studies they have
found prevalence of these fish tungue parasites in aquaculture that
are as high as like ninety eight percent. And there
have been some cases of like relatively high rates of
(54:39):
mortality in aquaculture species of fish. And that's not usually
due to a typical host parasite interaction, but maybe like
a parasite that doesn't typically infect that species of fish.
So there's not like a general conclusion that I can
draw from all of this, because there's so many different
space ease of these parasites that infect so many different
(55:03):
species of fish.
Speaker 1 (55:05):
Aaron, what about geographic range, Like are these parasite species
sort of distributed globally across the world or they increase
in prevalence or incidents or diversity as you get closer
to the equator.
Speaker 2 (55:21):
That's a good question. I didn't look at whether you
have like an increase in diversity with latitude and stuff
like that. I would assume similar to a lot of
other parasite and you know species in general, that you
probably see higher diversity in tropical areas that are warmer,
et cetera. A lot of the papers that tried to
look at like overall diversity of these parasites were very
(55:43):
region specific. So we have papers that are like, here's
the diversity in the Indian Ocean, here's the diversity in
this region, here's the diversity around Australia, and stuff like that.
So I didn't find any that were, well, there was
a couple actually that was like global diversity, but they're
just like really really broad and also don't tend to
be specific to just the tongue replacing simothoids, but are
(56:05):
looking at simothoids more broadly, because again, these can also
infect fish in other areas, not just in their tongue.
In any case, there's a lot of them. They're everywhere.
So where do we go from here?
Speaker 4 (56:22):
Right?
Speaker 2 (56:23):
There's so many open questions how many species are there?
Speaker 3 (56:27):
Really?
Speaker 2 (56:28):
Because we don't know are they changing in distribution? Like
are they moving around? And if so, why, what is
it that's driving changes in distribution? Why is it that
some species are much more host specific than others. What
are the factors they're driving this host specificity? I don't know,
so many questions.
Speaker 3 (56:47):
There are so many questions.
Speaker 2 (56:50):
Uh, and so I don't have answers to any of
those questions. There are so many people doing work to
better understand the natural history, the other the ecology of
these parasites. But I also wanted to end this episode
with some bits from I think the same paper.
Speaker 3 (57:11):
I have three Colin Carlson papers.
Speaker 1 (57:13):
So yeah, well, although it's not just it's not just Carlson.
Speaker 2 (57:18):
No Colin Carlson at all, A longtime friend of the
pod I've decided we're friends never met. But this was
the paper from twenty twenty that was published in Proceedings
of the Royal Society B and I just really appreciated
this paper not only for its thoroughness. It was like
(57:39):
a really long, detailed paper that essentially makes the case
for a real need to get a handle on the
existence of parasite diversity across the globe. And this paper
uses worms, mostly worms that do infect humans, as a
case study in this and it also goes into a
(58:01):
lot of detail on like how does one how do
we as a scientific community go about actually accomplishing this
and what does it mean for understanding our planet and
the health of our planet both now and of course
under conditions of climate change in the future. And so
I just want to I don't have profound things to
(58:25):
say as conclusion of this paper, but like, I just
do think that it's so this parasite, which is charismatic
in its own way right.
Speaker 3 (58:35):
More than other parasites, if we are allowed to be.
Speaker 2 (58:38):
The judge, yes, much more than other parasites, because it
is very cute, It is very startling, like it makes
you feel things, even if those things aren't like the
warm and fuzzies. I think that it gives us the
opportunity to really think about parasites in a way that
(58:58):
most people just don't ever think about parasites, or try
not to think about parasites. And so I want to
end with this one little quote from this paper. Quote.
Though some consider the task of cataloging parasite diversity a
testimony to human inquisitiveness, it is also a critical baseline
(59:19):
for understanding biological interactions in a world on the brink
of ecological collapse. End quote. And I feel like that's
an important thing to keep in mind. Parasites have a
lot that they can teach us, and we should learn
from them. Yeah, agreed, case case closed, not taking questions, thank.
Speaker 3 (59:43):
You, goodbye comments only.
Speaker 2 (59:46):
But we have lots of places that you can learn
more about these parasites. The simathoidiopods so cute and kill
so many other parasites and their roles in our ecosystem.
So let's say it with some.
Speaker 3 (59:58):
Sources, so so many sources.
Speaker 1 (01:00:01):
Arin, Okay, So I will shout out once again that
Bruska and Gilligan paper from nineteen eighty three that has
a great description of one of these parasites, and then
when it comes to the importance of parasites in ecosystems
and why we should conserve parasites. I have a million papers.
I really enjoyed one by Limberry and Smit from twenty
(01:00:22):
twenty three titled Conservation of Parasites A Primer, which I
also shouted out in the history section. But there are
so many ones out there that are not reviews but
like specific papers about this parasite in this ecosystem or
in this population, and it's just honestly really enlightening reading.
Speaker 2 (01:00:40):
I love it. I have a number of papers, more
than I expected for this episode. I also loved that
Brusken Gilligan paper. There was one from nineteen ninety eight
by Bunkley, Williams and Williams called Isopods associated with Fishes,
A Synopsis and Corrections, And then a one I really
love from twenty fourteen by Smit at all Global Diversity
(01:01:03):
of Fish Parasitic isopod Crustaceans of the family Simothoida. So
there's a few other papers that are more broadly about
the simothoids, and then a bunch of like specific ones
about this species versus that species et cetera. But as always,
we'll post the full list of our sources from this
episode and every single one of our episodes on our website,
This podcast will kill You dot Com. Check it out.
Speaker 3 (01:01:25):
Thank you to Bloodmobile for providing the music for this
episode and all.
Speaker 2 (01:01:29):
Of our episodes. Thank you to the film director of
the Bay Just Kidding. A thank you to Tom Bryfocal
and Leona Schoolatchi for the audio mixing.
Speaker 3 (01:01:39):
Thank you to everyone at Exactly Right.
Speaker 2 (01:01:41):
And thank you to you listeners. We hope that you
enjoyed this episode. We hope you love parasites a little
bit more than you did before. Yeah, and we hope
you learned something new and.
Speaker 1 (01:01:52):
A special thank you and shout out as always to
our fantastic patrons.
Speaker 3 (01:01:56):
Your support means the world.
Speaker 2 (01:01:57):
To us, it really does. Thank you. Well.
Speaker 3 (01:02:01):
Until next time, wash your hands
Speaker 2 (01:02:03):
You feel the animals
Hosts And Creators
Erin Welsh
Erin Allmann Updyke
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