March 21, 2017 • 49 mins
Unnatural tunnels worm and weave their way beneath centuries of accumulated London sprawl, and here a few natural creature assume unnatural behaviors -- including the humble mosquito. For wherever humans travel, into whatever new shapes they give the environment, the drinkers of their blood inherently follow. In this episode of Stuff to Blow Your Mind, Robert and Joe explore the curious ways of the London Underground mosquito. Mind the gap… between species!
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Episode Transcript
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Speaker 1 (00:03):
Welcome to Stuff to Blow your Mind from how Stuff
Works dot com. Hey you welcome to Stuff to Blow
your Mind. My name is Robert Land. I'm Joe McCormick.
You know Joe. I've I've long held a fascination with
underground transit system. Yeah, I like him too, Yeah, I
(00:24):
mean there are a totally unique space they are, and
it's you know, and it's one of those things that
I grew up in a more of a rural environment
and later in my life moved into urban environments where
I actually have and have had access to these various
underground train systems and have traveled to places, you know,
such as such as New York and London where they
(00:44):
have the most famous examples of the underground transit system.
But no matter where I am in that timeline, they're
always just as fascinating to me, whether there's something that
I only see in a horror movie or something that
is a part of my day to day life just
getting to and on work. They are such a unique
environment and such a cool thing. I'm the same way.
(01:05):
I'm kind of fascinated with them when I so, I
made it this far in my life without ever going
to New York until this past year. I went to
New York for the first time, and when I came back,
like the main thing I wanted to talk to everybody
about was the subway. I know. I was like, it's amazing.
There's stations everywhere you you know, just just around the corner,
(01:26):
you can go right in get to wherever you're going.
It's it's like, this is how a city should work. Yeah,
And it's also one of those cases where you grow
up watching all these movies. It's such as such a
location a fitting location for not only you know, horror
and monsters and mutants and chuds, but but also just
intrigued like interesting characters going places, and they do so
by traversing the underworld. Who's that woman in the overcoat
(01:49):
with the collar up at the other end of the station?
Did she just look at me? What's going on? Am
I being followed? But yeah, I like that you mentioned
the chud's because that is another aspect of what's great
about subway systems generally any underground transportation. Are there other
underground ground I said that, as if there's like underground
buses or canals. I'm not sure if there are, but yeah,
(02:12):
so the the underground trains, the tunnels, the tube, all
this stuff. When you go down into these spaces, it
is that you're literally entering a sub world where there
is a whole infrastructure. There's like a city under the city,
and in many of the big stations, there are things
in the stations underneath the city. Right, it's not just
(02:33):
like the train comes by, but there's like little shops
and encounters and stuff like that. Um, and it's uh,
it's this whole other world that's divorced from the sun.
It's separated by this solid barrier, and it's this alien
environment where it seems like unnatural things could happen. Yeah,
it's a true underworld. And we mis cycles around the
(02:56):
world for for ages have have had tails of underworlds
and uh and people that live underground, races that live underground,
and it wasn't until relatively modern times that we made
that truly possible. And they still have the mythic allure
that they had, you know, back when they were just
a dream. So is that what we're gonna be talking
(03:18):
about today morelocks? Well in a sense because uh, because
we are going to be taught, because we are going
to bring this back around to science. We are going
to talk about the the about the question what if
a species becomes trapped in the underworld, what happens over time?
Can it become a different species altogether? Can it become
(03:39):
a subspecies? And we have one very interesting example of
that current. All right, Well, one of the ways we
know you can create a new species or a new
subspecies is to significantly alter the environment in which you live,
right And so this is, I guess, is why we're
emphasizing this this alien world quality to the you know
there are a natural underground systems. Yeah, indeed, and it's
(04:03):
it's something that again we continue to read into it.
We create these worlds and then when we stand back,
when we say, wow, these are this is really strange
what we've done here with this completely artificial environment underground.
And countless writers and dreamers filmmakers have have taken that
and explored that territory. Two examples that come to mind
or Robert Barbara Johnson's a short story Far Below, which
(04:27):
is about ghouls in the tunnels beneath us, beneath New
York City. But when is that written? That was like
a weird tale, like a classic weird tales story. I
can't remember the publication date off hand, but it's like,
you know, classic twentieth century marriagery weird fiction. Yeah. Cool.
So that's a great one if anyone wants to check
that out. And then if anyone out there, and I'm
sure a lot of you are fans of Neil Gaiman's work, um,
(04:50):
he has explored this as well, the idea that the
the London Underground specifically is a gateway to a mystical
fairy world. Yeah, why wouldn't it be? Yeah, And uh,
you know a lot of this spills over into reality
too and interesting ways. Uh you know. The author of
Peter Ackroyd has is a wonderful book about London titled
(05:11):
London a Biography, and he points out several different, just
really weird, fascinating facts about the London Underground. Um. This
is one of my favorite quotes that I always think
about when I think about the Tube. He says, it
is a strange city beneath the ground, perhaps best exemplified
by worn man hole covers which, instead of reading self locking,
(05:33):
spell out elf king, which is great. I just I
can't shake that image of like looking down here's this
man made portal into the underworld, and it says elf
king like it literally, you know, names the it spells
out the dominion of of this ancient fairy lord that's
surely ruling over everything down below. I thought of just
(05:55):
one more reason why subway tunnels are so intriguing. It's
because you travel through them, but you don't get to
explore them. You can't go on foot. Yeah, all you
can do is look out. That's one of the things
I love about traveling by underground train is you look
out and inevitably there's like a forking tunnel, or there's
some sort of strange door or work area, or wait,
what's that? Yeah, what is that? Uh, that's that space
(06:17):
off to the left here. And then you read about
things such as ghost stations, of which there are several
in in London, there are a few in New York.
And what is that? It's a station that just isn't
used anymore, just an empty station. Uh. And these occur
with any train system also above the ground. But just
the idea of going through this old place occupied now
only by ghosts and maybe fading posters. It's just it's
(06:40):
just so rich. Or maybe some insect more locks, that's true.
That's true. We'll get to that now. One film in
particular that comes to mind on this topic is a
nineteen seventy two film by the name of Death Line,
and in the US it came out under the title
Raw Meat. And it's it's an interesting film. It's a
(07:02):
it's about a family of cannibals descended from Victorian railway
workers who wind up buried alive in the tunnels beneath London.
And uh. And I know that sounds incredible, but believe
it or not, the best part of the film, or
at least as far as I'm concerned, is that Donald
Pleasants is in it. And he plays instead of playing
like a stuffy academic or some sort of nefarious egghead
(07:25):
as he was wont to do. Uh, he plays a
blue collar police inspector named Inspector Calhoun. I don't believe you.
You know, you've got to check it out, he pleasant says.
Blue collar. Like he goes and gets a pint of
beer at the pub. There's like is I recall there's
an extended sequence in which he and his friend go
and get a get a beer at at the pub,
and it seems to go on for a very long time,
(07:48):
and I don't remember how it connects really to the
plot of the film, but at the time it felt
it felt as if the director was saying, Hey, this,
this guy is more interesting than all this cannibal stuff.
Let's just follow him for a while and then we'll
come back to the to the to the weird cannibal dude.
But with that voice back keep and now that pint
of ale. How that he didn't he didn't talk like.
That's one of the wonderful things about this. It's this, uh,
(08:10):
this more lively pleasants, more lively than than pretty much
any anything else I've seen him in. Okay, but he's
not an underground cannibal. No, he's just the police inspector.
All right, So where did the underground cannibals come in? Well,
it's the Victorian workers, the guys, the people who got
trapped underground. They have turned into a different subspecies of
(08:31):
human down there, and essentially they look like caveman, so
they haven't gotten full the descent here and turned into
more ghoulish characters. But there's basically one of these guys left.
He's the shaggy caveman of a dude, and he just
goes about um kind of oozing from sores and growling
and screaming and then attacking people and eating people. So
(08:55):
if this is from Victorian times, obviously this would not
be an enough time or enough generations to produce a
true human subspecies adapted to underground tunnels to produce cannibalistic morlocks.
Since Victorian times to the nineteen seventies, what would you
have had a few generations? Yeah, And into the movie's credit, Yeah,
(09:17):
they don't look like alien monsters. They look like shaggy humans,
or the one that we see looks like a shaggy human.
And uh, yeah, he goes about causing all this chaos.
And it's a fair warning. It's a disturbingly violent film
at times. It's a bit icky to watch. So you're
not necessarily saying go out and watch it. Not necessarily,
I mean, go go watch the trailer and if you
(09:37):
can see a scene with pleasants in it, and if
you know dark, violent, seventies hard is your thing, then
do check it out. But but I bring it up
because this ties directly into the real world science we're
talking about today. The question you have a creature is
locked away buried in the tubes beneath London, and it
(10:00):
has time to undergo generation after generation of of change
and adaptation. Can it become a different species? Can it
become a subspecies? What happens when the dark underworld gets
to do its work on natural world creatures? All right,
well we should take a quick break and when we
come back we will discuss the London Underground Mosquito. Okay,
(10:27):
we're back. So the London Underground Mosquito is going to
be what we're talking about today. You can probably guess
from the name that it lives in the London underground.
So what's the deal with the London underground Robert? Yeah,
I suppose we should just back up a few steps
and just talk about the tube itself, the environment and
which it dwells. Indeed, this is uh, this was the
(10:48):
world's first underground railway, opening in eighteen sixty three. Man,
that's early. Yeah, I would not have believed that it's
a It's grown and expanded significantly ever since then. And
so today you've got to eleven lines collected and they
collectively handle about four point eight million passengers a day
through two hundred seventy stations and two hundred and fifty
miles or four dred kilometers of track. Now, despite the name,
(11:11):
it's worth keeping in mind that only fort of that
is actually underground. There's plenty, plenty of plenty of track
that goes above ground. But still that's a lot of
underground track. Okay, So the London underground mosquito, that's the
London underground part mosquito part. Okay, Yeah, let's talk about
mosquitoes for a second. So what are they? Are they?
(11:33):
That's some kind of elephant I can't remember. Well, it's
interesting because the mosquito. We all know what the mosquito is.
We all have a very close relationship with it. It is,
or at least we have a very close relationship with
a few types of mosquito. And that's key because the
world is currently home to some thirty five hundred named
species of mosquitoes, and of those thirty five hundred, only
(11:56):
two hundred or so actually bother humans. But you know,
we're kind of irresistible, right, like the mosquito. We thrive
with these throughout most of the world, and we offer
large expanses of relatively hairless skin, all of it coursing
with delicious blood. Oh man, you don't usually think about
hair as being such a protective mechanism against parasitism like that.
(12:18):
But yeah, I mean, like, if you're a mosquito and
you come up against something really hairy, that's almost like
trying to get through barbed wire. And we're we're large
organisms compared to you know, most organisms. We're we're large,
relatively hairless, and we're everywhere, and so the mosquitoes everywhere.
Now the most common genera here are going to be
the awful ease Kulicks and the eighties mosquitoes. Now, mosquitoes
(12:42):
obviously are accomplished flyers, and anyone who's ever tried to
kill a mosquito can testify this. I had a as
a tangent here when I was recently um in Barbados.
I we largely didn't encounter mosquitoes at all, but we had,
you know, the Zico virus in our minds that we
were always on the lookout. And I was trapped in
(13:02):
the room by myself at one point with one mosquito
and it seems like it took forever for me to
to kill it. I finally had to do that trick
where you're like, all right, I'm gonna let you land
on me. I'm gonna let I'm gonna I'm gonna let
you feed or almost feed on me, and and I'll
do it to protect my family from from me. I'll
offer myself up as a sacrifice and then I will
(13:23):
kill you. But that's that's often the only way you
can get them. They're so surprisingly h skilled at at
getting out of the way of our our slaps and snacks. Well,
thanks for exposing me to Zeke and now Robert, that's
all right. I was not infected, so maybe I killed it.
It was one of you know, it was not infected itself. Well,
(13:44):
you know, you do hear about how these mosquito species
can traverse these long distances that you wouldn't expect In
one of the things we were reading today, it was
an exerpt from a book by a biologist named David Resnick,
who will get into more detail about later, but he
mentioned is the fact that you know, it used to
be that Hawaii didn't have mosquitoes that would bite humans.
(14:04):
Oh yeah, they got imported, not on purpose, I think,
wouldn't that be a great thing. No, No, But they're
like a lot of species. They they have a tremendous
ability to hitch rides on human transports, so they've managed
to invade whole new continents, uh, such as the invasive
yellow fever carrying eighties at jip Di that you find
(14:25):
in South America, which has been quite a problem. Um.
They also the cool thing to keep in mind about
mosquitoes is they benefit from an incredibly fast reproductive cycle. Now,
this is going to be important once we start talking
about the rates of evolution. That's right, Yeah, just how
because for the rate of evolution to to really be visible,
you have to have short periods, you have short lifespans
(14:48):
and fast reproduction cycle. And uh yeah, indeed that's the
case here. All they need is the tiniest bit of
standing water, uh, you know, abandoned swimming pools, bird baths
are great, but they'll also do just fine with a
at bowl, even a candy wrapper, a small puddle, or
even just a damp spot in the earth. They go
through four stages, adults, water, surface eggs, subsurface larvae. They
(15:10):
breathe through a kind of snorkele that pokes up through
the surface of the water, and a pupa stage. Now
they've been around roughly one million years. Isn't that great
to think about? Well, actually, it's not all that unusual
because we've all seen Jurassic Park. But had we not,
wouldn't it be fascinating to think about these little insects
biting dinosaurs? Yeah? You had just to think that this
(15:32):
this is something that uh, they've been so good at
for so long, and they're gonna they're not going away. Uh.
The oldest evidence we have for blood feeding mosquitoes comes
from a fossil that's known as proto mosquito, and this
is from the Triassic period about two million years ago,
so there were no flowering plants. So the elongated probiscus
(15:53):
is thought to have functioned like modern mosquitoes, you know,
for the drinking of blood. Oh you mean, so it's
like sin. There weren't plants, It didn't it couldn't be
like a hummingbird sticking its nose into something. If it's
sticking its nose into something, it was probably something that
had blood in it, right, that's the that's the theory.
Now you'll find mosquitoes now and every continent except Antarctica.
(16:14):
They thrive, and even our most exhaustive steps to eradicate
them often only work in the short term because again
they they're just so adapted, moving into new environments taking
advantage of the smallest quantities of water. Okay, so we've
got the two things there, the London underground the mosquito.
Let's let's make these great tastes taste nasty together. Yeah, So,
(16:35):
first of all, let's talk about the surface mosquito before
we talk about the you know, subsurface variant. All right,
So the species we're talking about is Coolex pipians and
according to biologist David Resnick, who I'll cite more deeply,
especially towards the end of this episode, uh pippians is
the single most widespread mosquito in the world. It's all
over the place. It is a disease vector known to
(16:58):
spread Westnile virus as well as some forms of encephalitis
and meningitis. And it mates in these big swarms that
take place out in open areas, and then it deposits
its fertilized eggs in the form of a floating raft
of eggs on still water. Resinic rather elegantly, I think
lists quote untended bird baths, forgotten buckets in the backyard,
(17:20):
discarded automobile tires, clogged, rain gutters, or wherever else. Fetid, stagnant,
water accumulates. I love that. One of my favorite words
is fetted. That's really good. Now, once these rafts of
eggs start to hatch, they turn into, as you mentioned
in the general mosquito life cycle earlier, the water dwelling
(17:41):
larva stage. And these larva eat these eat small things
that live in the water, you know, eat microbes for sustenance.
And then about ten days into the larval stage and
they come out of the water as adults begin feeding
and being the breeding process. So the females seek out
a blood meal, which in wholes pipians almost always comes
(18:02):
from a bird. Why well, because bird blood is good stuff.
Don't be a food snob at the cool ex Pippians.
After you've got a blood meal from a bird, you've
got enough nutrition to invest in forming some eggs. And
this is important because it goes blood meal then eggs.
You need the blood in order to make the eggs. Uh.
And then once you've got the eggs, you can start
(18:22):
the whole process over again with a mating swarm or
what I think should be called a swargy. I like
that swargy and it is it is worth noting the
whole male female mosquito thing here, right, because the females
are the ones that that feed on blood. The males
do not. And you're one, what are the males that
(18:42):
if they don't eat blood, well, they depend they feed
on flowers and plants, many many, A beautiful swamp orchid
depends on mosquitoes for the pollination, so that the blood
is directly tied to the reproductive cycle of the female. Right.
So now in London there appears to be a totally
normal form of this species found on the surface doing
(19:05):
all the normal stuff, feeding on birds, getting the blood
meal before reproducing, and that's standard Koulex pippions pippions, But
they're also appears to be a subterranean variant of this
species in the London underground, that's right. And londoners uh
supposedly first discovered them during the blitz of World War two.
(19:28):
So German bombers terrorized the night skies and and roughly
one roughly one hundred and eighty thousand people sheltered in
the tunnels, just as they had during World War One.
Can you imagine that It's like you're you're fleeing bombing
of your city, and the last thing you want is
to be swarmed with mosquitoes in the dark, I know.
And that's what happened. They had to contend with not
(19:49):
only some mosquitoes, but apparently lies and ticks. Uh. And
everyone knows about rats in the subways and sewers to
go back to my perhaps h you know, childish and
enthusiasm for underground transportation. I always get a little excited
when I see a subway rat, even though I know
you're not supposed to see one, and it's bad, it's
you know, it's it's an infectious road and and all that.
(20:12):
But I still get excited because it's like, it's it's
like seeing a unicorn. I don't know what. So, I
don't like to see a rat in my house, but
when I see a rat scamper across the marta tracks like.
I love that feeling of seeing it dart out from
cover and go to somewhere else, I'm like, yeah, go buddy.
It's like that scene in in the Last Unicorn. You
remember at the beginning where the the old man and
(20:32):
the younger hunter glimpse the unicorn in the distance and
the the old man like takes the man the kid
aside and says, you've seen something special today. There are
not many of them left in the world, you know.
It's that's how I feel about the subway rat. Now.
So you say, people notice these mosquitoes in the underground
in World War two? But is that when they were
(20:54):
first there or were they there before? Then the mosquitoes
are the people the mosquitoes? Okay, because it is because
again I I do want to point out that world
War One you saw similar to the tune of a
third of a million Londoners going down there. And there's
a wonderful quote here that I ran across from from
Ackroyd's book. But he points out that Philip Ziegler in
(21:15):
the book London at War related that quote. One of
the principal fears of the authorities is that a deep
shelter mentality might grow up and result in paralysis of
the will among those who succumbed to it. It was
also suggested that the underground Londoners would grow hysterical with
fear and would never surface to perform their duties. So
they were actually afraid of something sort of like the
(21:38):
raw meat scenario, like death line that that people would
go down there to take shelter and that they would
just not be able to come back up. Yeah. And
I think this it's important to note in looking at
a film like like Death Line. Uh. And it feeds
into just sort of the the industrial age paranoia of
of of of the English and and really modern Western life,
(22:01):
the idea that we're we're changing our world through this
industrial movement, our cities are becoming these inhuman places, and
like the underground tunnel and the idea of cowering down
there and you know, protecting yourselves from from these bombings. Uh,
it becomes a perfect symbol of that. Well, it is
something we're thinking about because in a biological sense, our
(22:22):
environments really do define us. They shape our very biology.
You know, the way your hands are, the way your
eyes work, the way your teeth are, and the way
your brain defines your behavior, that's all shaped by the
environment your ancestors come from. You know, it's what genetic
options the environment had to work with and then molding
that to survive and reproduce best in it. So your
(22:44):
environment does define you. I think that's not something to
just be laughed off as paranoia. No, no, Um, and
you know they're they're also all these wonderful tales, you know,
many probably folkloric in nature, about people known as firm
ers or rakes or flushers. These were people who clean
sewage tunnel blocks, as well as tashers, who are hunters
(23:06):
of valuables in the sewers and tunnels underneath London. These
are some great UH British isms, tash ers firmers. So
their tales of like tashas and firmers uh becoming lost
in this subworld maze and eventually they either fall dead
from exhaustion and they grow so weak that a swarm
of rats just eats them alive. So anyway, the humans
(23:27):
had been going down unbeneath London for some time. They
had created this additional mythos and this UH and these
various expressions of their fear regarding the underworld, and indeed
the mosquitoes had been down there for some time too.
Based on the research we're looking at, it seems that
there it's thought that you had different points when mosquitoes
(23:48):
were introduced to this underground though world, and then they
become trapped down there. But since they're that they have
what they need down there they managed to survive because
there are rats, there are humans. It's where the humans go.
You almost have this captive uh ever, changing food supply, right,
So this does make us wondered, I mean, should we
(24:11):
should start to think about You've got these mosquitoes that
live underground, you've got the mosquitoes that live above ground.
They appear to both be some form of cool expipians.
But are the ones underground actually a different animal? Now
that is an excellent question, and after one more quick break,
we shall explore it. So after the war, no one
(24:38):
forgot about the tunnels for sure, but yeah, I guess
there was a lot else to to worry about. Uh,
people kind of forgot about the mosquitoes down in the tubes.
You didn't see a lot of attention really surrounding them. Occasionally,
you know, there would be workers who who would you know,
want to wind up with mosquito bites, and they reported
and certainly, you know, people who were going down on
a regular basis might have noticed them. But for the
(25:00):
most part, nobody really gave them much attention. And then
about fifty years after the close of World War Two,
you had Katherine Burn come around. Now she was a
doctoral student at the time, and she decided to investigate.
So she collected mosquitoes from seven different subterranean sites, and
(25:21):
in all there were something like twenty sites covering outdoor, indoor,
and subterranean locations around London. And then the researchers reared
the captured mosquitoes. They attempted cross breeding, cross breeding between
mosquitoes and mosquitoes, not between mosquitoes and humans, just to
go and get that out of the way. Um. And
they they found that the kulicks pippians in the underground
(25:44):
behaved rather differently from those that lived on the surface.
So for example, uh, surface uh pippians only drank the
blood of birds. But this uh, this new subspecies, this
Skulis Pippians molestus, they call it. This one drank and blunt. Now,
I gotta make it worse than that, because to to
really excite your used needles, squick, they feed primarily on
(26:08):
humans and rats, So because what else you're gonna feed
on down there? Yeah, So if you're down in the
tube in London and you feel an itch on your neck,
it's possible that the last thing that sharp little probosis
went into before your skin might have been another person,
or it might have been the belly of one member
of a huge cockney rat and that was a wonderful image.
(26:32):
But yeah, that's always one of the concerns with the
parasitic organism, like who else has it been feeding on?
And what else has it been feeding on? Right? Uh
so yeah, so there there was a resulting paper here right,
published in the journal Heredity in nine It was Burns
paper with Richard Nickel, and it was called Kool Expipians
in London Underground Tunnels differentiation between surface and subterranean populations.
(26:56):
All right, so let's talk about some of these differences
that we see. So, uh, the core that the core
differences of course, so we already mentioned that the mosquitoes
are are consuming primarily the blood of rats and humans
because that is west down there, mammal blood. Yeah. Now,
the other things to keep in mind is that this
the molestus mosquitoes. They don't need as much space anymore
(27:16):
because they are living in confined tubes, and that is
that that has an impact on how they reproduce because
they're not they're then not depending on these big you know,
what do you what do you call them swargies? These uh,
big open air, open space swarming mating swarms. Yeah, these
are these big mating swarms are not occurring in the underworld.
(27:37):
They are and instead going with you know, a smaller
scale reproductive breeding then scheduled venue if you will. Yeah.
And on top of that, they are they are largely
protected from colder weather, so they forego winter hibernation. And
interestingly enough, they don't need that blood meal necessarily to
lay their eggs. Now, this is to say that to
(28:01):
get tentantical on the blood stuff. This means that they
are autogeneous. They do not require a blood meal in
order to lay eggs. Where he mentioned how the male
and female mosquitoes consume nectar and plant juices, the females
and the species just need that blood meal to energize
their egg production right now, part of the reproductive cycle. Right.
And if you look at mosquitoes around the world, all
(28:21):
the different species, some do require that blood meal, some don't,
and some merely benefit from it, which is to say,
they can produce eggs without the blood meal. But if
they get the blood meal, they're gonna it's gonna be
that you know, much stronger of an egg production. So
in short, it appeared that the mosquitoes adapted to the underworld,
they became so distinct even that they could no longer
(28:44):
breed or would no longer breed with their surface dwell
and kin different and this is because different mating behaviors,
different reproductive behavior. No mating swarms, just individual lovers finding
each other in the the subway tunnels. Well, I guess
this leads us to the question. Obviously we've had since
the beginning of the London Underground some form of divergent
(29:06):
evolution going on here. But but does this count as
a different species? That's sort of the question, especially a
lay person might want to ask, well, is it really
a different animal? Now? Uh? Is it a speciation event? Yeah?
Because I think one of the big questions to consider is,
you know, to what extent are they biologically and or
behaviorally unable to breed with the surface world mosquitoes of
(29:29):
their species? So these would this would be sort of
the standard definition of a species division right now. Of course,
that this is bearing in mind that distinct but closely
related species can sometimes technically breed to produce hybrid offspring,
though sometimes they're infertile or otherwise compromised. Right, So I
think now is a good time to, uh take a
(29:49):
look at a chapter from a book by the biologist
David Resnick, who I mentioned earlier. And this book is
called The Origin, Then and Now, An Interpretive guy to
the Origin of Species that was published by Princeton University
Press in two thousand eleven. And in a chapter on
in this book, Resident discusses the specific example of the
(30:12):
London London underground mosquito and whether or not it is
speciation and what what this means for the concept of speciation.
Uh So, a central question in biology. How long does
it take for evolution to form a new species? How
long should you have to wait? Obviously this could depend
on a lot of different factors. Right, You've got different
(30:34):
mutation rates, maybe um if mutations are sort of providing
the changes that lead to new new body forms and
stuff like that, You've got different selection pressures, you've got
different rates of reproduction. You're probably more likely to see
faster revolution in organisms that produce more generations in a
(30:55):
short period of time, like we're mentioning earlier, like bacteria
or even like in sects like fruit flies and stuff,
very quick turnover. I mean, that's why something why fruit fly.
One of the reasons fruit flies are used so much
in research because you can you can watch this occur,
and certainly when you find examples of evolution and action,
so called evolution and action, that's what you're looking at
(31:16):
species that have those really really tight turnaround in reproduction.
But another thing that often leads to UH speciation, at
least as far as we think, is having highly specific
different selection pressures, putting a group in isolation and then
making it uh very hard for that group to live
(31:36):
except by one or two ways, and this tends to
force adaptation to those new ways of life, which produces
it creates kind of a narrow adaptive bottleneck through which
genes have to pass. So um Resnick says in his
book that he's not certain that these mosquitoes in the
London under London Underground constitute a different species, but he
(31:58):
argues that if they're not a distinct species, they're definitely
on the way. In the quote, they have moved far
down the path toward forming a reproductively isolated network of populations,
which is the currently accepted definition of species. So that's
going to what we said a minute ago, reproductive isolation.
What what we generally think of as a species is
(32:18):
breeds with with its own kind, doesn't breed with others.
So let's review what we've said so far and add
a few more things about our observations about the difference
between standard cool ex Pippians and then the ones down
in the tube. So, like we said, uh, surface cool
ex pippians mate in these swarms and open areas. The
subterranean ones made in close cramped conditions. Um. You mentioned
(32:42):
the winter hibernation. That's an interesting one because the surface
pippians have what's known as a seasonal dia pause because
come on, I mean, they live all the way up
in Britain. Cold winter is not a good place for mosquitoes,
so it gets really cold up there during the cold
weather months. Pippians stop mating, they build up a store
of fat reserves, and they essentially hunker down to wait
(33:05):
out the cold weather. Um, subterranean Pippians they don't have
winter to deal with. It's, you know, pretty much the
same climate year round down there in the tubes, fairly warm,
so they don't have this seasonal diapause anymore. They stay
active all year, they stay breeding all year. They just
keep going. They're like a fine wine in a wine
cellar hermetically sealed and just kept it a constant aging aging,
(33:32):
acquiring finesse um by fighting rat kings, and then beautiful
red liquid as well. Yeah, so another one. We mentioned
this before. Surface pippians feed almost exclusively on bird blood, right.
The subterranean pippians don't have access to many birds for
obvious reasons. Though this didn't make me think when we
were talking about it earlier that it would be really
(33:55):
cool to have a speciation event producing subterranean birds, like
like albino subterranean vultures that only live in I don't know,
subway tunnels or caves or some other'd be great. I
guess the like the closest thing that comes to mind
would be some I guess something like a kiwi. You
know that's kind of like a ground dwelling like semi
(34:16):
burrowing bird. They burrow. I didn't know that kiwi's uh
if I remember correctly, uh and u Qwi experts can
can correct me in this. They do. They do some
sort of burrowing. Yeah, I mean not like full blown,
you know, tremmors burrowing, but they'll they dig around like
they live very close to the soil. Well, what I
(34:37):
want is bone white vultures with red eyes living exclusively
in caves. I could see it and see it happening.
I mean, I I look finally back on these. Uh,
these are these different flightless prehistoric birds. So I like
the idea of them returning in a subworld environment. Okay,
back to the pippians. So surface pippians, as we mentioned before,
also remember they get a blood meal before they produce
(34:59):
their eggs. You gotta get some blood then you lay
your eggs. The subterranean ones they can easily skip the
meal if necessary. Uh. The question would be why why
can they do that? Well, down in the tunnels there
is plenty to eat in the form of water based
microbial life that the larva consume in their larval stage.
The blood is more scarce, So if you can get
(35:19):
through your life cycle on on that, that's a good thing.
Now back to burn and nichols In as you mentioned. So,
so we said earlier that there are other subterranean mosquitoes
elsewhere in the world, right did we mention that? I
think we did. Um, the ones in the London underground
are not the only ones where where mosquitoes are dwelling
in some kind of underground space. But how can we
(35:41):
tell whether these mosquitoes in London, in the London underground
are a subterranean mosquitoes imported from somewhere else in the world,
You know how, because we've already discussed how how how
skilled they are at adapting to new new environments traveling
with humans, or are they surface missque autos from London
(36:01):
that moved underground and began to change. And this is
where the genetic testing you alluded to earlier comes in.
So you mentioned the mosquitoes collected from different sites throughout
the underground and throughout the surface. They got mosquitoes from
seven sites throughout the underground network and then twelve different
sites above the surface like gardens and ponds, And what
(36:22):
they wanted to look for was genetic variation at twenty
different loci within the genes, to see if the genes
of the underground mosquitoes matched the genes of the above
ground ones, or if they've got these unique allele's um
that would that would be matching to uh underground mosquitoes
from other places around the world. And what they found
(36:44):
was that the underground mosquitoes in London did not have
these unique alleles that were common to underground mosquitoes from
other places. They had the same alleles as their above
ground cousins in London. Another thing they found interestingly underground
miss guitos. Uh, maybe this isn't the correct term scientifically,
but they're kind of inbred. Like, well, that would make sense,
(37:07):
and then that comes back to death line, like this
is kind of a an inbred, uneducated creature that's so
walking around, right, So there's relative homogeneity in the genes
of the underground population compared to the surface. The ones
on the surface have a lot more genetic diversity because
they have a lot more different breeding options. The ones underground,
we're sort of like, I don't know, you might think
(37:29):
of them as like insect Baldwin brothers, you know, a
little bit of variation between them, but not as much
variation as you'd find within the general population. Um. So
this is also what you'd expect if you had a
small population of original mosquitoes that moved into the underground
and began breeding with each other and had just been
(37:49):
breeding with each other in their descendants ever since. So
what's the conclusion here, Well, it looks like a small
handful of colonists. Mosquitoes from the surface made this plunge
into the darkness sometime in the past, maybe very far back,
maybe when the tunnels were first being dug um, and
they managed to survive long and uh long enough and
(38:11):
to reproduce enough for the environment to begin to shape
their biology. But then again, as we mentioned, is it
a different species. This would really come down to the
aspects of reproductive isolation. If they can't interbreed, we probably
think it is uh, it is a different species. And
specifically it's if they can't interbreed producing viable offspring down
(38:34):
multiple generations, because some things might be able to interbreed
and produce an offspring that itself can't breed, right Yeah,
and this is where we get into the various sterile
hybrids that we see with other species. Right. So, what
Burne and Nichols found was that the underground mosquitoes could
interbreed with one another and produce fertile offspring, but every
(38:55):
time they tried to make a female underground mosquito with
a group of males from the surface, no eggs were produced.
Underground females can mate successfully with underground males, but not
usually with surface males um so Resinic points out another
really interesting thing from their research, which is how Burne
and Nichols also found evidence of mosquito colonists pushing the
(39:17):
boundaries of habitat tolerance in both directions, and so, for example,
at the Oval station in the other ground, they found
surface mosquitoes were trying to survive under the surface in
a flooded tunnel at the bottom of an open shaft.
They were trying to live underground, but they still these
(39:38):
surface mosquitoes trying to live underground still needed a blood
meal to produce eggs, and they couldn't breed with the
underground mosquitoes. Meanwhile, a colony of underground mosquitoes was discovered
biting humans in houses in southeast London. So they were
trying to migrate up and live on the surface, but
they were genetically similar to the underground mosquitoes, and unfortunately
(40:00):
for them, they don't know how to do this winter diapause,
you know, the seasonal diapause. They can't hunker down for
the cold weather, so when it comes along it will
smite them. Huh. See. Now this is an idea that
doesn't explored enough in our various weird fictions. Not the
idea that there's some sort of an underground humanoid species,
but the idea that the underground humanoid species then comes
(40:22):
up and maybe tries, you know, they try to get jobs,
they can't adapt, They move into a flat and they
just feel horribly because of course they're they're cannibalistic monsters. Well,
they'll they will be used to a very constant environmental
condition to you know, climate control essentially. You know, caves
are sort of climate controlled. When they come up to
the surface summer and winter, it's gonna be awful. They're
(40:43):
gonna be like, what is this water pouring out of
my armpits? I hate it? Uh you know, I guess
in a way, it's kind of the vampire myth as
we often encounter. It is kind of a play on
this because you think of you think of old Count
Dracula coming over to London imported like a mosquito and
then the hold of a ship um very limited in
what he can do outside during the day. Uh So,
(41:05):
so maybe it has been explored, uh you know, to
add nauseum already. Uh So the authors of the original study,
they were careful not actually to get drawn into a
big argument about whether the two populations are technically different
species or not, but they were more focused on the
process of speciation rather than trying to arbitrate the dividing line.
(41:26):
But even if these two mosquitoes are not now separate species,
they're clearly on the way there. So Resonic points out
that this provides an example of reproductive isolation in many
fewer generations than Darwin would have expected. And that's kind
of interesting, right. You know. Darwin thought, well, you need
maybe x many different generations to really produce a different species.
(41:49):
But if we're almost there or already there with these mosquitoes,
doesn't doesn't take nearly as long as Darwin would have guessed.
But then again, keep in mind that these are mosquitoes,
very fast reproduct of cycle, you know, their insects. The
same thing doesn't necessarily apply to oak trees or rhinoceros,
is alright, So if if reproductive isolation does happen is fast,
(42:11):
why well. Resinnick has a couple of hypotheses in his
chapter that I think are interesting. One of them is
the idea of disruptive selection. Uh. And the way he
explains this is that the survival requirements for the two
environments above ground and below ground are so different that
if you were to successfully make a surface pippions with
(42:34):
an underground pippions, it's offspring would very likely have fatal
deficiencies for either environment. What, you know, the traits you'd
get from your mom would make you unable to live
in dad's world. Where the traits you'd get from your
dad would make you unable to live in your mom's world. Uh.
And so if it's on the surface, cold weather might
(42:54):
kill it. If it's in the other ground, it doesn't
know how to hunt the right food, It can't put
off the blood yell that it you know, we'll have
a hard time finding or something like that. And this
prevents a kind of back interaction with the general population
of the underground mosquitoes and enforces genetic isolation. But another
way to possibly explain it would be changes in reproductive behavior.
(43:18):
So what if these two populations have diverged in a
way that specifically selected breeding behaviors that are incompatible. Uh.
Think of the open area swarming versus the confined space
breeding is just one example. They simply don't get down
with the way the other population tends to mate. So
mating doesn't happen reinforcing reproductive isolation, and as far as
(43:41):
I know, either of those are live options, or it
could be a combination. So something to keep in mind here.
As a Burn points out in the paper quote, the
differences between Pippins and Molestus forms seem to change from
place to place within the range of the species. The
ostensibly clear cut distinction between the Molestas and Pippians forms
(44:02):
in northern Europe is not so apparent in the northern
Mediterranean area and may disappear in some populations further south. Yeah,
and that makes sense because think about it. For example,
one major difference between the London surface and the London
underground is the presence or absence of this cold weather
diapause if there are If there are similar above and
(44:24):
below ground populations and consistently warm climates, they're just less
likely to have this difference, right, because the surface mosquitoes
don't need to become dormant for cold weather in a
place where there is no cold weather. Yes, that's a
good point. So Resinic discusses a few other interesting takeaways
in this chapter. One is to simply cast a sort
of doubt on the total relevance of distinctions between species. Like,
(44:47):
on one hand, it's very scientifically useful to have labels
for things that are alike in order to separate them
from things that they are unlike. Uh. And and really
that very notion is at the core of what science is,
right categorization of Miller things with one another. But it's
also true that these boundaries are kind of porous and
that the concept of a species does not actually operate
(45:07):
in reality. And reality there are things. There are genes,
their chromosomes, their phenotypic traits, there are environments. A species
is more kind of a concept, and Resinic writes, quote,
species in nature should be thought of as fluid mosaics
of populations that are becoming locally adapted uh, sometimes with
(45:30):
the aid of similar adaptations attained by long extinct populations
that adapted to similar environments. So a couple of interesting
things there. One is this idea of species just being
many individuals with genes that are always in flux. Things
are coming and going. It's not a standard, totally defined
(45:51):
thing with boundaries. It's just a family of resemblances. And
then the other thing is that the last part about
Miller adaptations attained from long extinct populations. One thing that
often appears to happen in cases of reproductive isolation is
that some rare gene in the general population that doesn't
(46:11):
seem to do much or provide much advantage, suddenly becomes
useful in a specific environment and it becomes selected four,
and it gets pumped up and becomes more prevalent and
comes to define the new population. And it's very possible
that this gene was something that was useful to an
ancestor of this current population. So it's like that you
(46:33):
can adapt by pulling antiques out of the past when
they suddenly become useful again, you might need that blunderbuss,
not now, but sometime in the future. Yeah. Indeed, I
mean we we see this in various experiments where they're
like they switched the epogenetic switch to say, um, you know,
make chickens a little more like dinosaurs again. Yeah, some
(46:55):
tweaking some one aspect of their anatomy because that option
is still They're like that, like the options in a
video game shouldn't need to be turned on. Um. And
hopefully I didn't anthropomorphizes evolution too much. For some of
our listeners, there. Oh, we just got a complaint about that. Yeah,
well you know sometimes, but that was also from somebody
who didn't believe in evolution, So okay, they saically they
(47:17):
didn't think we went far enough. All right. Well, on
that note, we actually asked you did we go too far?
Did we not go far enough? But more importantly, I'd
love to hear from anybody who you know, shares our
love for underground transit systems. I'd love to hear from
anyone who's ever been bitten by a London underground mosquito. Yeah,
(47:40):
did you feel the proboscis? Yeah, of the mollst us
or you know. It would be great if anyone's listening
to this podcast on the train in the London underground,
if they are bitten by a mosquito during this podcast.
I think that would be a pretty magical moment as well.
This mach al right. Well, on that note, hey, if
(48:02):
you want to check out more information on this topic,
go to the landing page for this episode at stuff
to Blow your Mind dot Com. Should be up there,
nice and bright on the banner, and you also find
all the links out to our various social media accounts
such as Facebook, Tumbler, Instagram, and Twitter, and hey, if
you are a Twitter user, take part in this whole
tripod that initiative used the hashtag tripod with hy to
(48:27):
just suggest your favorite podcast, the podcast that that that
to your life with a little joy as you traverse
the subway and deal with rats and mosquitoes or what
have you. For my own part, I'm a big fan
of Ideas with Paul Kennedy. Yeah, yeah, yeah. It's a
wonderful Canadian radio show podcast fixed for a number of
tremendous uh philosophical, scientific, artistic, historic topics. It varies from
(48:51):
week to week. Well, why don't you tell us what
podcast you out there like? So if you want to
get in touch with us directly, you can email us.
As always, blow the mind at how staff Work's dot
(49:12):
for more on this and thousands of other topics. Is
it how stuff works dot com the biggest
Welcome to Stuff to Blow your Mind from how Stuff
Works dot com. Hey you welcome to Stuff to Blow
your Mind. My name is Robert Land. I'm Joe McCormick.
You know Joe. I've I've long held a fascination with
underground transit system. Yeah, I like him too, Yeah, I
(00:24):
mean there are a totally unique space they are, and
it's you know, and it's one of those things that
I grew up in a more of a rural environment
and later in my life moved into urban environments where
I actually have and have had access to these various
underground train systems and have traveled to places, you know,
such as such as New York and London where they
(00:44):
have the most famous examples of the underground transit system.
But no matter where I am in that timeline, they're
always just as fascinating to me, whether there's something that
I only see in a horror movie or something that
is a part of my day to day life just
getting to and on work. They are such a unique
environment and such a cool thing. I'm the same way.
(01:05):
I'm kind of fascinated with them when I so, I
made it this far in my life without ever going
to New York until this past year. I went to
New York for the first time, and when I came back,
like the main thing I wanted to talk to everybody
about was the subway. I know. I was like, it's amazing.
There's stations everywhere you you know, just just around the corner,
(01:26):
you can go right in get to wherever you're going.
It's it's like, this is how a city should work. Yeah,
And it's also one of those cases where you grow
up watching all these movies. It's such as such a
location a fitting location for not only you know, horror
and monsters and mutants and chuds, but but also just
intrigued like interesting characters going places, and they do so
by traversing the underworld. Who's that woman in the overcoat
(01:49):
with the collar up at the other end of the station?
Did she just look at me? What's going on? Am
I being followed? But yeah, I like that you mentioned
the chud's because that is another aspect of what's great
about subway systems generally any underground transportation. Are there other
underground ground I said that, as if there's like underground
buses or canals. I'm not sure if there are, but yeah,
(02:12):
so the the underground trains, the tunnels, the tube, all
this stuff. When you go down into these spaces, it
is that you're literally entering a sub world where there
is a whole infrastructure. There's like a city under the city,
and in many of the big stations, there are things
in the stations underneath the city. Right, it's not just
(02:33):
like the train comes by, but there's like little shops
and encounters and stuff like that. Um, and it's uh,
it's this whole other world that's divorced from the sun.
It's separated by this solid barrier, and it's this alien
environment where it seems like unnatural things could happen. Yeah,
it's a true underworld. And we mis cycles around the
(02:56):
world for for ages have have had tails of underworlds
and uh and people that live underground, races that live underground,
and it wasn't until relatively modern times that we made
that truly possible. And they still have the mythic allure
that they had, you know, back when they were just
a dream. So is that what we're gonna be talking
(03:18):
about today morelocks? Well in a sense because uh, because
we are going to be taught, because we are going
to bring this back around to science. We are going
to talk about the the about the question what if
a species becomes trapped in the underworld, what happens over time?
Can it become a different species altogether? Can it become
(03:39):
a subspecies? And we have one very interesting example of
that current. All right, Well, one of the ways we
know you can create a new species or a new
subspecies is to significantly alter the environment in which you live,
right And so this is, I guess, is why we're
emphasizing this this alien world quality to the you know
there are a natural underground systems. Yeah, indeed, and it's
(04:03):
it's something that again we continue to read into it.
We create these worlds and then when we stand back,
when we say, wow, these are this is really strange
what we've done here with this completely artificial environment underground.
And countless writers and dreamers filmmakers have have taken that
and explored that territory. Two examples that come to mind
or Robert Barbara Johnson's a short story Far Below, which
(04:27):
is about ghouls in the tunnels beneath us, beneath New
York City. But when is that written? That was like
a weird tale, like a classic weird tales story. I
can't remember the publication date off hand, but it's like,
you know, classic twentieth century marriagery weird fiction. Yeah. Cool.
So that's a great one if anyone wants to check
that out. And then if anyone out there, and I'm
sure a lot of you are fans of Neil Gaiman's work, um,
(04:50):
he has explored this as well, the idea that the
the London Underground specifically is a gateway to a mystical
fairy world. Yeah, why wouldn't it be? Yeah, And uh,
you know a lot of this spills over into reality
too and interesting ways. Uh you know. The author of
Peter Ackroyd has is a wonderful book about London titled
(05:11):
London a Biography, and he points out several different, just
really weird, fascinating facts about the London Underground. Um. This
is one of my favorite quotes that I always think
about when I think about the Tube. He says, it
is a strange city beneath the ground, perhaps best exemplified
by worn man hole covers which, instead of reading self locking,
(05:33):
spell out elf king, which is great. I just I
can't shake that image of like looking down here's this
man made portal into the underworld, and it says elf
king like it literally, you know, names the it spells
out the dominion of of this ancient fairy lord that's
surely ruling over everything down below. I thought of just
(05:55):
one more reason why subway tunnels are so intriguing. It's
because you travel through them, but you don't get to
explore them. You can't go on foot. Yeah, all you
can do is look out. That's one of the things
I love about traveling by underground train is you look
out and inevitably there's like a forking tunnel, or there's
some sort of strange door or work area, or wait,
what's that? Yeah, what is that? Uh, that's that space
(06:17):
off to the left here. And then you read about
things such as ghost stations, of which there are several
in in London, there are a few in New York.
And what is that? It's a station that just isn't
used anymore, just an empty station. Uh. And these occur
with any train system also above the ground. But just
the idea of going through this old place occupied now
only by ghosts and maybe fading posters. It's just it's
(06:40):
just so rich. Or maybe some insect more locks, that's true.
That's true. We'll get to that now. One film in
particular that comes to mind on this topic is a
nineteen seventy two film by the name of Death Line,
and in the US it came out under the title
Raw Meat. And it's it's an interesting film. It's a
(07:02):
it's about a family of cannibals descended from Victorian railway
workers who wind up buried alive in the tunnels beneath London.
And uh. And I know that sounds incredible, but believe
it or not, the best part of the film, or
at least as far as I'm concerned, is that Donald
Pleasants is in it. And he plays instead of playing
like a stuffy academic or some sort of nefarious egghead
(07:25):
as he was wont to do. Uh, he plays a
blue collar police inspector named Inspector Calhoun. I don't believe you.
You know, you've got to check it out, he pleasant says.
Blue collar. Like he goes and gets a pint of
beer at the pub. There's like is I recall there's
an extended sequence in which he and his friend go
and get a get a beer at at the pub,
and it seems to go on for a very long time,
(07:48):
and I don't remember how it connects really to the
plot of the film, but at the time it felt
it felt as if the director was saying, Hey, this,
this guy is more interesting than all this cannibal stuff.
Let's just follow him for a while and then we'll
come back to the to the to the weird cannibal dude.
But with that voice back keep and now that pint
of ale. How that he didn't he didn't talk like.
That's one of the wonderful things about this. It's this, uh,
(08:10):
this more lively pleasants, more lively than than pretty much
any anything else I've seen him in. Okay, but he's
not an underground cannibal. No, he's just the police inspector.
All right, So where did the underground cannibals come in? Well,
it's the Victorian workers, the guys, the people who got
trapped underground. They have turned into a different subspecies of
(08:31):
human down there, and essentially they look like caveman, so
they haven't gotten full the descent here and turned into
more ghoulish characters. But there's basically one of these guys left.
He's the shaggy caveman of a dude, and he just
goes about um kind of oozing from sores and growling
and screaming and then attacking people and eating people. So
(08:55):
if this is from Victorian times, obviously this would not
be an enough time or enough generations to produce a
true human subspecies adapted to underground tunnels to produce cannibalistic morlocks.
Since Victorian times to the nineteen seventies, what would you
have had a few generations? Yeah, And into the movie's credit, Yeah,
(09:17):
they don't look like alien monsters. They look like shaggy humans,
or the one that we see looks like a shaggy human.
And uh, yeah, he goes about causing all this chaos.
And it's a fair warning. It's a disturbingly violent film
at times. It's a bit icky to watch. So you're
not necessarily saying go out and watch it. Not necessarily,
I mean, go go watch the trailer and if you
(09:37):
can see a scene with pleasants in it, and if
you know dark, violent, seventies hard is your thing, then
do check it out. But but I bring it up
because this ties directly into the real world science we're
talking about today. The question you have a creature is
locked away buried in the tubes beneath London, and it
(10:00):
has time to undergo generation after generation of of change
and adaptation. Can it become a different species? Can it
become a subspecies? What happens when the dark underworld gets
to do its work on natural world creatures? All right,
well we should take a quick break and when we
come back we will discuss the London Underground Mosquito. Okay,
(10:27):
we're back. So the London Underground Mosquito is going to
be what we're talking about today. You can probably guess
from the name that it lives in the London underground.
So what's the deal with the London underground Robert? Yeah,
I suppose we should just back up a few steps
and just talk about the tube itself, the environment and
which it dwells. Indeed, this is uh, this was the
(10:48):
world's first underground railway, opening in eighteen sixty three. Man,
that's early. Yeah, I would not have believed that it's
a It's grown and expanded significantly ever since then. And
so today you've got to eleven lines collected and they
collectively handle about four point eight million passengers a day
through two hundred seventy stations and two hundred and fifty
miles or four dred kilometers of track. Now, despite the name,
(11:11):
it's worth keeping in mind that only fort of that
is actually underground. There's plenty, plenty of plenty of track
that goes above ground. But still that's a lot of
underground track. Okay, So the London underground mosquito, that's the
London underground part mosquito part. Okay, Yeah, let's talk about
mosquitoes for a second. So what are they? Are they?
(11:33):
That's some kind of elephant I can't remember. Well, it's
interesting because the mosquito. We all know what the mosquito is.
We all have a very close relationship with it. It is,
or at least we have a very close relationship with
a few types of mosquito. And that's key because the
world is currently home to some thirty five hundred named
species of mosquitoes, and of those thirty five hundred, only
(11:56):
two hundred or so actually bother humans. But you know,
we're kind of irresistible, right, like the mosquito. We thrive
with these throughout most of the world, and we offer
large expanses of relatively hairless skin, all of it coursing
with delicious blood. Oh man, you don't usually think about
hair as being such a protective mechanism against parasitism like that.
(12:18):
But yeah, I mean, like, if you're a mosquito and
you come up against something really hairy, that's almost like
trying to get through barbed wire. And we're we're large
organisms compared to you know, most organisms. We're we're large,
relatively hairless, and we're everywhere, and so the mosquitoes everywhere.
Now the most common genera here are going to be
the awful ease Kulicks and the eighties mosquitoes. Now, mosquitoes
(12:42):
obviously are accomplished flyers, and anyone who's ever tried to
kill a mosquito can testify this. I had a as
a tangent here when I was recently um in Barbados.
I we largely didn't encounter mosquitoes at all, but we had,
you know, the Zico virus in our minds that we
were always on the lookout. And I was trapped in
(13:02):
the room by myself at one point with one mosquito
and it seems like it took forever for me to
to kill it. I finally had to do that trick
where you're like, all right, I'm gonna let you land
on me. I'm gonna let I'm gonna I'm gonna let
you feed or almost feed on me, and and I'll
do it to protect my family from from me. I'll
offer myself up as a sacrifice and then I will
(13:23):
kill you. But that's that's often the only way you
can get them. They're so surprisingly h skilled at at
getting out of the way of our our slaps and snacks. Well,
thanks for exposing me to Zeke and now Robert, that's
all right. I was not infected, so maybe I killed it.
It was one of you know, it was not infected itself. Well,
(13:44):
you know, you do hear about how these mosquito species
can traverse these long distances that you wouldn't expect In
one of the things we were reading today, it was
an exerpt from a book by a biologist named David Resnick,
who will get into more detail about later, but he
mentioned is the fact that you know, it used to
be that Hawaii didn't have mosquitoes that would bite humans.
(14:04):
Oh yeah, they got imported, not on purpose, I think,
wouldn't that be a great thing. No, No, But they're
like a lot of species. They they have a tremendous
ability to hitch rides on human transports, so they've managed
to invade whole new continents, uh, such as the invasive
yellow fever carrying eighties at jip Di that you find
(14:25):
in South America, which has been quite a problem. Um.
They also the cool thing to keep in mind about
mosquitoes is they benefit from an incredibly fast reproductive cycle. Now,
this is going to be important once we start talking
about the rates of evolution. That's right, Yeah, just how
because for the rate of evolution to to really be visible,
you have to have short periods, you have short lifespans
(14:48):
and fast reproduction cycle. And uh yeah, indeed that's the
case here. All they need is the tiniest bit of
standing water, uh, you know, abandoned swimming pools, bird baths
are great, but they'll also do just fine with a
at bowl, even a candy wrapper, a small puddle, or
even just a damp spot in the earth. They go
through four stages, adults, water, surface eggs, subsurface larvae. They
(15:10):
breathe through a kind of snorkele that pokes up through
the surface of the water, and a pupa stage. Now
they've been around roughly one million years. Isn't that great
to think about? Well, actually, it's not all that unusual
because we've all seen Jurassic Park. But had we not,
wouldn't it be fascinating to think about these little insects
biting dinosaurs? Yeah? You had just to think that this
(15:32):
this is something that uh, they've been so good at
for so long, and they're gonna they're not going away. Uh.
The oldest evidence we have for blood feeding mosquitoes comes
from a fossil that's known as proto mosquito, and this
is from the Triassic period about two million years ago,
so there were no flowering plants. So the elongated probiscus
(15:53):
is thought to have functioned like modern mosquitoes, you know,
for the drinking of blood. Oh you mean, so it's
like sin. There weren't plants, It didn't it couldn't be
like a hummingbird sticking its nose into something. If it's
sticking its nose into something, it was probably something that
had blood in it, right, that's the that's the theory.
Now you'll find mosquitoes now and every continent except Antarctica.
(16:14):
They thrive, and even our most exhaustive steps to eradicate
them often only work in the short term because again
they they're just so adapted, moving into new environments taking
advantage of the smallest quantities of water. Okay, so we've
got the two things there, the London underground the mosquito.
Let's let's make these great tastes taste nasty together. Yeah, So,
(16:35):
first of all, let's talk about the surface mosquito before
we talk about the you know, subsurface variant. All right,
So the species we're talking about is Coolex pipians and
according to biologist David Resnick, who I'll cite more deeply,
especially towards the end of this episode, uh pippians is
the single most widespread mosquito in the world. It's all
over the place. It is a disease vector known to
(16:58):
spread Westnile virus as well as some forms of encephalitis
and meningitis. And it mates in these big swarms that
take place out in open areas, and then it deposits
its fertilized eggs in the form of a floating raft
of eggs on still water. Resinic rather elegantly, I think
lists quote untended bird baths, forgotten buckets in the backyard,
(17:20):
discarded automobile tires, clogged, rain gutters, or wherever else. Fetid, stagnant,
water accumulates. I love that. One of my favorite words
is fetted. That's really good. Now, once these rafts of
eggs start to hatch, they turn into, as you mentioned
in the general mosquito life cycle earlier, the water dwelling
(17:41):
larva stage. And these larva eat these eat small things
that live in the water, you know, eat microbes for sustenance.
And then about ten days into the larval stage and
they come out of the water as adults begin feeding
and being the breeding process. So the females seek out
a blood meal, which in wholes pipians almost always comes
(18:02):
from a bird. Why well, because bird blood is good stuff.
Don't be a food snob at the cool ex Pippians.
After you've got a blood meal from a bird, you've
got enough nutrition to invest in forming some eggs. And
this is important because it goes blood meal then eggs.
You need the blood in order to make the eggs. Uh.
And then once you've got the eggs, you can start
(18:22):
the whole process over again with a mating swarm or
what I think should be called a swargy. I like
that swargy and it is it is worth noting the
whole male female mosquito thing here, right, because the females
are the ones that that feed on blood. The males
do not. And you're one, what are the males that
(18:42):
if they don't eat blood, well, they depend they feed
on flowers and plants, many many, A beautiful swamp orchid
depends on mosquitoes for the pollination, so that the blood
is directly tied to the reproductive cycle of the female. Right.
So now in London there appears to be a totally
normal form of this species found on the surface doing
(19:05):
all the normal stuff, feeding on birds, getting the blood
meal before reproducing, and that's standard Koulex pippions pippions, But
they're also appears to be a subterranean variant of this
species in the London underground, that's right. And londoners uh
supposedly first discovered them during the blitz of World War two.
(19:28):
So German bombers terrorized the night skies and and roughly
one roughly one hundred and eighty thousand people sheltered in
the tunnels, just as they had during World War One.
Can you imagine that It's like you're you're fleeing bombing
of your city, and the last thing you want is
to be swarmed with mosquitoes in the dark, I know.
And that's what happened. They had to contend with not
(19:49):
only some mosquitoes, but apparently lies and ticks. Uh. And
everyone knows about rats in the subways and sewers to
go back to my perhaps h you know, childish and
enthusiasm for underground transportation. I always get a little excited
when I see a subway rat, even though I know
you're not supposed to see one, and it's bad, it's
you know, it's it's an infectious road and and all that.
(20:12):
But I still get excited because it's like, it's it's
like seeing a unicorn. I don't know what. So, I
don't like to see a rat in my house, but
when I see a rat scamper across the marta tracks like.
I love that feeling of seeing it dart out from
cover and go to somewhere else, I'm like, yeah, go buddy.
It's like that scene in in the Last Unicorn. You
remember at the beginning where the the old man and
(20:32):
the younger hunter glimpse the unicorn in the distance and
the the old man like takes the man the kid
aside and says, you've seen something special today. There are
not many of them left in the world, you know.
It's that's how I feel about the subway rat. Now.
So you say, people notice these mosquitoes in the underground
in World War two? But is that when they were
(20:54):
first there or were they there before? Then the mosquitoes
are the people the mosquitoes? Okay, because it is because
again I I do want to point out that world
War One you saw similar to the tune of a
third of a million Londoners going down there. And there's
a wonderful quote here that I ran across from from
Ackroyd's book. But he points out that Philip Ziegler in
(21:15):
the book London at War related that quote. One of
the principal fears of the authorities is that a deep
shelter mentality might grow up and result in paralysis of
the will among those who succumbed to it. It was
also suggested that the underground Londoners would grow hysterical with
fear and would never surface to perform their duties. So
they were actually afraid of something sort of like the
(21:38):
raw meat scenario, like death line that that people would
go down there to take shelter and that they would
just not be able to come back up. Yeah. And
I think this it's important to note in looking at
a film like like Death Line. Uh. And it feeds
into just sort of the the industrial age paranoia of
of of of the English and and really modern Western life,
(22:01):
the idea that we're we're changing our world through this
industrial movement, our cities are becoming these inhuman places, and
like the underground tunnel and the idea of cowering down
there and you know, protecting yourselves from from these bombings. Uh,
it becomes a perfect symbol of that. Well, it is
something we're thinking about because in a biological sense, our
(22:22):
environments really do define us. They shape our very biology.
You know, the way your hands are, the way your
eyes work, the way your teeth are, and the way
your brain defines your behavior, that's all shaped by the
environment your ancestors come from. You know, it's what genetic
options the environment had to work with and then molding
that to survive and reproduce best in it. So your
(22:44):
environment does define you. I think that's not something to
just be laughed off as paranoia. No, no, Um, and
you know they're they're also all these wonderful tales, you know,
many probably folkloric in nature, about people known as firm
ers or rakes or flushers. These were people who clean
sewage tunnel blocks, as well as tashers, who are hunters
(23:06):
of valuables in the sewers and tunnels underneath London. These
are some great UH British isms, tash ers firmers. So
their tales of like tashas and firmers uh becoming lost
in this subworld maze and eventually they either fall dead
from exhaustion and they grow so weak that a swarm
of rats just eats them alive. So anyway, the humans
(23:27):
had been going down unbeneath London for some time. They
had created this additional mythos and this UH and these
various expressions of their fear regarding the underworld, and indeed
the mosquitoes had been down there for some time too.
Based on the research we're looking at, it seems that
there it's thought that you had different points when mosquitoes
(23:48):
were introduced to this underground though world, and then they
become trapped down there. But since they're that they have
what they need down there they managed to survive because
there are rats, there are humans. It's where the humans go.
You almost have this captive uh ever, changing food supply, right,
So this does make us wondered, I mean, should we
(24:11):
should start to think about You've got these mosquitoes that
live underground, you've got the mosquitoes that live above ground.
They appear to both be some form of cool expipians.
But are the ones underground actually a different animal? Now
that is an excellent question, and after one more quick break,
we shall explore it. So after the war, no one
(24:38):
forgot about the tunnels for sure, but yeah, I guess
there was a lot else to to worry about. Uh,
people kind of forgot about the mosquitoes down in the tubes.
You didn't see a lot of attention really surrounding them. Occasionally,
you know, there would be workers who who would you know,
want to wind up with mosquito bites, and they reported
and certainly, you know, people who were going down on
a regular basis might have noticed them. But for the
(25:00):
most part, nobody really gave them much attention. And then
about fifty years after the close of World War Two,
you had Katherine Burn come around. Now she was a
doctoral student at the time, and she decided to investigate.
So she collected mosquitoes from seven different subterranean sites, and
(25:21):
in all there were something like twenty sites covering outdoor, indoor,
and subterranean locations around London. And then the researchers reared
the captured mosquitoes. They attempted cross breeding, cross breeding between
mosquitoes and mosquitoes, not between mosquitoes and humans, just to
go and get that out of the way. Um. And
they they found that the kulicks pippians in the underground
(25:44):
behaved rather differently from those that lived on the surface.
So for example, uh, surface uh pippians only drank the
blood of birds. But this uh, this new subspecies, this
Skulis Pippians molestus, they call it. This one drank and blunt. Now,
I gotta make it worse than that, because to to
really excite your used needles, squick, they feed primarily on
(26:08):
humans and rats, So because what else you're gonna feed
on down there? Yeah, So if you're down in the
tube in London and you feel an itch on your neck,
it's possible that the last thing that sharp little probosis
went into before your skin might have been another person,
or it might have been the belly of one member
of a huge cockney rat and that was a wonderful image.
(26:32):
But yeah, that's always one of the concerns with the
parasitic organism, like who else has it been feeding on?
And what else has it been feeding on? Right? Uh
so yeah, so there there was a resulting paper here right,
published in the journal Heredity in nine It was Burns
paper with Richard Nickel, and it was called Kool Expipians
in London Underground Tunnels differentiation between surface and subterranean populations.
(26:56):
All right, so let's talk about some of these differences
that we see. So, uh, the core that the core
differences of course, so we already mentioned that the mosquitoes
are are consuming primarily the blood of rats and humans
because that is west down there, mammal blood. Yeah. Now,
the other things to keep in mind is that this
the molestus mosquitoes. They don't need as much space anymore
(27:16):
because they are living in confined tubes, and that is
that that has an impact on how they reproduce because
they're not they're then not depending on these big you know,
what do you what do you call them swargies? These uh,
big open air, open space swarming mating swarms. Yeah, these
are these big mating swarms are not occurring in the underworld.
(27:37):
They are and instead going with you know, a smaller
scale reproductive breeding then scheduled venue if you will. Yeah.
And on top of that, they are they are largely
protected from colder weather, so they forego winter hibernation. And
interestingly enough, they don't need that blood meal necessarily to
lay their eggs. Now, this is to say that to
(28:01):
get tentantical on the blood stuff. This means that they
are autogeneous. They do not require a blood meal in
order to lay eggs. Where he mentioned how the male
and female mosquitoes consume nectar and plant juices, the females
and the species just need that blood meal to energize
their egg production right now, part of the reproductive cycle. Right.
And if you look at mosquitoes around the world, all
(28:21):
the different species, some do require that blood meal, some don't,
and some merely benefit from it, which is to say,
they can produce eggs without the blood meal. But if
they get the blood meal, they're gonna it's gonna be
that you know, much stronger of an egg production. So
in short, it appeared that the mosquitoes adapted to the underworld,
they became so distinct even that they could no longer
(28:44):
breed or would no longer breed with their surface dwell
and kin different and this is because different mating behaviors,
different reproductive behavior. No mating swarms, just individual lovers finding
each other in the the subway tunnels. Well, I guess
this leads us to the question. Obviously we've had since
the beginning of the London Underground some form of divergent
(29:06):
evolution going on here. But but does this count as
a different species? That's sort of the question, especially a
lay person might want to ask, well, is it really
a different animal? Now? Uh? Is it a speciation event? Yeah?
Because I think one of the big questions to consider is,
you know, to what extent are they biologically and or
behaviorally unable to breed with the surface world mosquitoes of
(29:29):
their species? So these would this would be sort of
the standard definition of a species division right now. Of course,
that this is bearing in mind that distinct but closely
related species can sometimes technically breed to produce hybrid offspring,
though sometimes they're infertile or otherwise compromised. Right, So I
think now is a good time to, uh take a
(29:49):
look at a chapter from a book by the biologist
David Resnick, who I mentioned earlier. And this book is
called The Origin, Then and Now, An Interpretive guy to
the Origin of Species that was published by Princeton University
Press in two thousand eleven. And in a chapter on
in this book, Resident discusses the specific example of the
(30:12):
London London underground mosquito and whether or not it is
speciation and what what this means for the concept of speciation.
Uh So, a central question in biology. How long does
it take for evolution to form a new species? How
long should you have to wait? Obviously this could depend
on a lot of different factors. Right, You've got different
(30:34):
mutation rates, maybe um if mutations are sort of providing
the changes that lead to new new body forms and
stuff like that, You've got different selection pressures, you've got
different rates of reproduction. You're probably more likely to see
faster revolution in organisms that produce more generations in a
(30:55):
short period of time, like we're mentioning earlier, like bacteria
or even like in sects like fruit flies and stuff,
very quick turnover. I mean, that's why something why fruit fly.
One of the reasons fruit flies are used so much
in research because you can you can watch this occur,
and certainly when you find examples of evolution and action,
so called evolution and action, that's what you're looking at
(31:16):
species that have those really really tight turnaround in reproduction.
But another thing that often leads to UH speciation, at
least as far as we think, is having highly specific
different selection pressures, putting a group in isolation and then
making it uh very hard for that group to live
(31:36):
except by one or two ways, and this tends to
force adaptation to those new ways of life, which produces
it creates kind of a narrow adaptive bottleneck through which
genes have to pass. So um Resnick says in his
book that he's not certain that these mosquitoes in the
London under London Underground constitute a different species, but he
(31:58):
argues that if they're not a distinct species, they're definitely
on the way. In the quote, they have moved far
down the path toward forming a reproductively isolated network of populations,
which is the currently accepted definition of species. So that's
going to what we said a minute ago, reproductive isolation.
What what we generally think of as a species is
(32:18):
breeds with with its own kind, doesn't breed with others.
So let's review what we've said so far and add
a few more things about our observations about the difference
between standard cool ex Pippians and then the ones down
in the tube. So, like we said, uh, surface cool
ex pippians mate in these swarms and open areas. The
subterranean ones made in close cramped conditions. Um. You mentioned
(32:42):
the winter hibernation. That's an interesting one because the surface
pippians have what's known as a seasonal dia pause because
come on, I mean, they live all the way up
in Britain. Cold winter is not a good place for mosquitoes,
so it gets really cold up there during the cold
weather months. Pippians stop mating, they build up a store
of fat reserves, and they essentially hunker down to wait
(33:05):
out the cold weather. Um, subterranean Pippians they don't have
winter to deal with. It's, you know, pretty much the
same climate year round down there in the tubes, fairly warm,
so they don't have this seasonal diapause anymore. They stay
active all year, they stay breeding all year. They just
keep going. They're like a fine wine in a wine
cellar hermetically sealed and just kept it a constant aging aging,
(33:32):
acquiring finesse um by fighting rat kings, and then beautiful
red liquid as well. Yeah, so another one. We mentioned
this before. Surface pippians feed almost exclusively on bird blood, right.
The subterranean pippians don't have access to many birds for
obvious reasons. Though this didn't make me think when we
were talking about it earlier that it would be really
(33:55):
cool to have a speciation event producing subterranean birds, like
like albino subterranean vultures that only live in I don't know,
subway tunnels or caves or some other'd be great. I
guess the like the closest thing that comes to mind
would be some I guess something like a kiwi. You
know that's kind of like a ground dwelling like semi
(34:16):
burrowing bird. They burrow. I didn't know that kiwi's uh
if I remember correctly, uh and u Qwi experts can
can correct me in this. They do. They do some
sort of burrowing. Yeah, I mean not like full blown,
you know, tremmors burrowing, but they'll they dig around like
they live very close to the soil. Well, what I
(34:37):
want is bone white vultures with red eyes living exclusively
in caves. I could see it and see it happening.
I mean, I I look finally back on these. Uh,
these are these different flightless prehistoric birds. So I like
the idea of them returning in a subworld environment. Okay,
back to the pippians. So surface pippians, as we mentioned before,
also remember they get a blood meal before they produce
(34:59):
their eggs. You gotta get some blood then you lay
your eggs. The subterranean ones they can easily skip the
meal if necessary. Uh. The question would be why why
can they do that? Well, down in the tunnels there
is plenty to eat in the form of water based
microbial life that the larva consume in their larval stage.
The blood is more scarce, So if you can get
(35:19):
through your life cycle on on that, that's a good thing.
Now back to burn and nichols In as you mentioned. So,
so we said earlier that there are other subterranean mosquitoes
elsewhere in the world, right did we mention that? I
think we did. Um, the ones in the London underground
are not the only ones where where mosquitoes are dwelling
in some kind of underground space. But how can we
(35:41):
tell whether these mosquitoes in London, in the London underground
are a subterranean mosquitoes imported from somewhere else in the world,
You know how, because we've already discussed how how how
skilled they are at adapting to new new environments traveling
with humans, or are they surface missque autos from London
(36:01):
that moved underground and began to change. And this is
where the genetic testing you alluded to earlier comes in.
So you mentioned the mosquitoes collected from different sites throughout
the underground and throughout the surface. They got mosquitoes from
seven sites throughout the underground network and then twelve different
sites above the surface like gardens and ponds, And what
(36:22):
they wanted to look for was genetic variation at twenty
different loci within the genes, to see if the genes
of the underground mosquitoes matched the genes of the above
ground ones, or if they've got these unique allele's um
that would that would be matching to uh underground mosquitoes
from other places around the world. And what they found
(36:44):
was that the underground mosquitoes in London did not have
these unique alleles that were common to underground mosquitoes from
other places. They had the same alleles as their above
ground cousins in London. Another thing they found interestingly underground
miss guitos. Uh, maybe this isn't the correct term scientifically,
but they're kind of inbred. Like, well, that would make sense,
(37:07):
and then that comes back to death line, like this
is kind of a an inbred, uneducated creature that's so
walking around, right, So there's relative homogeneity in the genes
of the underground population compared to the surface. The ones
on the surface have a lot more genetic diversity because
they have a lot more different breeding options. The ones underground,
we're sort of like, I don't know, you might think
(37:29):
of them as like insect Baldwin brothers, you know, a
little bit of variation between them, but not as much
variation as you'd find within the general population. Um. So
this is also what you'd expect if you had a
small population of original mosquitoes that moved into the underground
and began breeding with each other and had just been
(37:49):
breeding with each other in their descendants ever since. So
what's the conclusion here, Well, it looks like a small
handful of colonists. Mosquitoes from the surface made this plunge
into the darkness sometime in the past, maybe very far back,
maybe when the tunnels were first being dug um, and
they managed to survive long and uh long enough and
(38:11):
to reproduce enough for the environment to begin to shape
their biology. But then again, as we mentioned, is it
a different species. This would really come down to the
aspects of reproductive isolation. If they can't interbreed, we probably
think it is uh, it is a different species. And
specifically it's if they can't interbreed producing viable offspring down
(38:34):
multiple generations, because some things might be able to interbreed
and produce an offspring that itself can't breed, right Yeah,
and this is where we get into the various sterile
hybrids that we see with other species. Right. So, what
Burne and Nichols found was that the underground mosquitoes could
interbreed with one another and produce fertile offspring, but every
(38:55):
time they tried to make a female underground mosquito with
a group of males from the surface, no eggs were produced.
Underground females can mate successfully with underground males, but not
usually with surface males um so Resinic points out another
really interesting thing from their research, which is how Burne
and Nichols also found evidence of mosquito colonists pushing the
(39:17):
boundaries of habitat tolerance in both directions, and so, for example,
at the Oval station in the other ground, they found
surface mosquitoes were trying to survive under the surface in
a flooded tunnel at the bottom of an open shaft.
They were trying to live underground, but they still these
(39:38):
surface mosquitoes trying to live underground still needed a blood
meal to produce eggs, and they couldn't breed with the
underground mosquitoes. Meanwhile, a colony of underground mosquitoes was discovered
biting humans in houses in southeast London. So they were
trying to migrate up and live on the surface, but
they were genetically similar to the underground mosquitoes, and unfortunately
(40:00):
for them, they don't know how to do this winter diapause,
you know, the seasonal diapause. They can't hunker down for
the cold weather, so when it comes along it will
smite them. Huh. See. Now this is an idea that
doesn't explored enough in our various weird fictions. Not the
idea that there's some sort of an underground humanoid species,
but the idea that the underground humanoid species then comes
(40:22):
up and maybe tries, you know, they try to get jobs,
they can't adapt, They move into a flat and they
just feel horribly because of course they're they're cannibalistic monsters. Well,
they'll they will be used to a very constant environmental
condition to you know, climate control essentially. You know, caves
are sort of climate controlled. When they come up to
the surface summer and winter, it's gonna be awful. They're
(40:43):
gonna be like, what is this water pouring out of
my armpits? I hate it? Uh you know, I guess
in a way, it's kind of the vampire myth as
we often encounter. It is kind of a play on
this because you think of you think of old Count
Dracula coming over to London imported like a mosquito and
then the hold of a ship um very limited in
what he can do outside during the day. Uh So,
(41:05):
so maybe it has been explored, uh you know, to
add nauseum already. Uh So the authors of the original study,
they were careful not actually to get drawn into a
big argument about whether the two populations are technically different
species or not, but they were more focused on the
process of speciation rather than trying to arbitrate the dividing line.
(41:26):
But even if these two mosquitoes are not now separate species,
they're clearly on the way there. So Resonic points out
that this provides an example of reproductive isolation in many
fewer generations than Darwin would have expected. And that's kind
of interesting, right. You know. Darwin thought, well, you need
maybe x many different generations to really produce a different species.
(41:49):
But if we're almost there or already there with these mosquitoes,
doesn't doesn't take nearly as long as Darwin would have guessed.
But then again, keep in mind that these are mosquitoes,
very fast reproduct of cycle, you know, their insects. The
same thing doesn't necessarily apply to oak trees or rhinoceros,
is alright, So if if reproductive isolation does happen is fast,
(42:11):
why well. Resinnick has a couple of hypotheses in his
chapter that I think are interesting. One of them is
the idea of disruptive selection. Uh. And the way he
explains this is that the survival requirements for the two
environments above ground and below ground are so different that
if you were to successfully make a surface pippions with
(42:34):
an underground pippions, it's offspring would very likely have fatal
deficiencies for either environment. What, you know, the traits you'd
get from your mom would make you unable to live
in dad's world. Where the traits you'd get from your
dad would make you unable to live in your mom's world. Uh.
And so if it's on the surface, cold weather might
(42:54):
kill it. If it's in the other ground, it doesn't
know how to hunt the right food, It can't put
off the blood yell that it you know, we'll have
a hard time finding or something like that. And this
prevents a kind of back interaction with the general population
of the underground mosquitoes and enforces genetic isolation. But another
way to possibly explain it would be changes in reproductive behavior.
(43:18):
So what if these two populations have diverged in a
way that specifically selected breeding behaviors that are incompatible. Uh.
Think of the open area swarming versus the confined space
breeding is just one example. They simply don't get down
with the way the other population tends to mate. So
mating doesn't happen reinforcing reproductive isolation, and as far as
(43:41):
I know, either of those are live options, or it
could be a combination. So something to keep in mind here.
As a Burn points out in the paper quote, the
differences between Pippins and Molestus forms seem to change from
place to place within the range of the species. The
ostensibly clear cut distinction between the Molestas and Pippians forms
(44:02):
in northern Europe is not so apparent in the northern
Mediterranean area and may disappear in some populations further south. Yeah,
and that makes sense because think about it. For example,
one major difference between the London surface and the London
underground is the presence or absence of this cold weather
diapause if there are If there are similar above and
(44:24):
below ground populations and consistently warm climates, they're just less
likely to have this difference, right, because the surface mosquitoes
don't need to become dormant for cold weather in a
place where there is no cold weather. Yes, that's a
good point. So Resinic discusses a few other interesting takeaways
in this chapter. One is to simply cast a sort
of doubt on the total relevance of distinctions between species. Like,
(44:47):
on one hand, it's very scientifically useful to have labels
for things that are alike in order to separate them
from things that they are unlike. Uh. And and really
that very notion is at the core of what science is,
right categorization of Miller things with one another. But it's
also true that these boundaries are kind of porous and
that the concept of a species does not actually operate
(45:07):
in reality. And reality there are things. There are genes,
their chromosomes, their phenotypic traits, there are environments. A species
is more kind of a concept, and Resinic writes, quote,
species in nature should be thought of as fluid mosaics
of populations that are becoming locally adapted uh, sometimes with
(45:30):
the aid of similar adaptations attained by long extinct populations
that adapted to similar environments. So a couple of interesting
things there. One is this idea of species just being
many individuals with genes that are always in flux. Things
are coming and going. It's not a standard, totally defined
(45:51):
thing with boundaries. It's just a family of resemblances. And
then the other thing is that the last part about
Miller adaptations attained from long extinct populations. One thing that
often appears to happen in cases of reproductive isolation is
that some rare gene in the general population that doesn't
(46:11):
seem to do much or provide much advantage, suddenly becomes
useful in a specific environment and it becomes selected four,
and it gets pumped up and becomes more prevalent and
comes to define the new population. And it's very possible
that this gene was something that was useful to an
ancestor of this current population. So it's like that you
(46:33):
can adapt by pulling antiques out of the past when
they suddenly become useful again, you might need that blunderbuss,
not now, but sometime in the future. Yeah. Indeed, I
mean we we see this in various experiments where they're
like they switched the epogenetic switch to say, um, you know,
make chickens a little more like dinosaurs again. Yeah, some
(46:55):
tweaking some one aspect of their anatomy because that option
is still They're like that, like the options in a
video game shouldn't need to be turned on. Um. And
hopefully I didn't anthropomorphizes evolution too much. For some of
our listeners, there. Oh, we just got a complaint about that. Yeah,
well you know sometimes, but that was also from somebody
who didn't believe in evolution, So okay, they saically they
(47:17):
didn't think we went far enough. All right. Well, on
that note, we actually asked you did we go too far?
Did we not go far enough? But more importantly, I'd
love to hear from anybody who you know, shares our
love for underground transit systems. I'd love to hear from
anyone who's ever been bitten by a London underground mosquito. Yeah,
(47:40):
did you feel the proboscis? Yeah, of the mollst us
or you know. It would be great if anyone's listening
to this podcast on the train in the London underground,
if they are bitten by a mosquito during this podcast.
I think that would be a pretty magical moment as well.
This mach al right. Well, on that note, hey, if
(48:02):
you want to check out more information on this topic,
go to the landing page for this episode at stuff
to Blow your Mind dot Com. Should be up there,
nice and bright on the banner, and you also find
all the links out to our various social media accounts
such as Facebook, Tumbler, Instagram, and Twitter, and hey, if
you are a Twitter user, take part in this whole
tripod that initiative used the hashtag tripod with hy to
(48:27):
just suggest your favorite podcast, the podcast that that that
to your life with a little joy as you traverse
the subway and deal with rats and mosquitoes or what
have you. For my own part, I'm a big fan
of Ideas with Paul Kennedy. Yeah, yeah, yeah. It's a
wonderful Canadian radio show podcast fixed for a number of
tremendous uh philosophical, scientific, artistic, historic topics. It varies from
(48:51):
week to week. Well, why don't you tell us what
podcast you out there like? So if you want to
get in touch with us directly, you can email us.
As always, blow the mind at how staff Work's dot
(49:12):
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