Emily: This episode is brought to you through a collaboration
with the Smithsonian's National Museum of Natural History in Washington DC
and the Field Museum in Chicago, Illinois.
Emily: What do you think of when I say worm?
My first thought is these guys, earthworms.
The one most people are familiar with is a "Lumbricus terrestris",
sometimes referred to as night crawlers.
But I recently learned that there are around six thousand named and described species of earthworm alone
This is just the tip of the worm iceberg
There's so much more to know about them
Mostly because worm is a deceivingly misleading concept with no easy definition or description.
In fact,
there are perhaps as many as a few
hundred thousand species of worms and some of them are as different from one another as you or I are from a
starfish. To help me answer the question What is a worm?
I came to the Smithsonian's National Museum of Natural History to talk
with Dr. Anna Phillips, who's one of three curators of worms.
Emily: We are here what what collection are we in?
Anna: We are in the invertebrate zoology collections at the
National Museum of Natural History, the Smithsonian, this is a room that houses everything from mollusks to
Arthropods and crustaceans to worms.
Emily: So how many worms do you have in the collection here?
I mean the Smithsonian Museum has some of the largest collections
in the world if not the largest worm collection.
Anna: We have at least four hundred and twenty-seven thousand specimens of worms
we probably have more.
Emily: So, can you define what is worm?
Anna: There are things that tend to be long and thin and
they don't have backbones.
There's a lot of things that can be like that that may not actually be worms
So it's a little bit of a difficult question. It's a general term that describes sort of a body plan
It may be surprising to some people but there's many different kinds of worms
out there. Turns out there's about 12 phyla of worms in the world.
Emily: And so, if you can imagine the taxonomic tree of life, I guess what it what does it mean to be a
separate phylum?
Anna: So it goes from kingdom, phylum, class, order,
family, genus, species. phylum means that they're all within the animal kingdom
and they all are very very different from each other
Emily: So what it phylum are people in?
Anna: We're in, Chordata, yes.
Emily: So we are more closely related to
squirrels and lizards and snakes
Anna: And fish
Emily: And fish
than any of these worms are related to one another.
Anna: Right.
Emily: So can we talk about some of these different worms now that we sort of know
that like worm worm is like a catch-all
phrase.
Anna: Here we have a selection of some worms. Some of these are the larger specimens.
We have everything from some Polychaetas
these are marine worms and then we also have worms who live inside of vertebrates like
Nematodes,
Tapeworms some of the larval stages of the parasitic worms.
Emily: Like this one these weird balloon things.
Anna: So these are larvae of tapeworms.
Emily: Those are baby tapeworms.
Anna: Yeah.
Emily: Really cute
Anna: It's a little different because they have complex life cycles so they're gonna pass through this larval stage
On their way to being an adult and a different host.
You wouldn't necessarily recognize that this worm looks very similar to this.
Emily: Yeah, like I mean this looks like some spaghetti.
Anna: Yeah, a lot of people compare it to pasta.
Emily: We probably shouldn't do that will ruin pasta for people.
Anna: Don't eat tapeworms.
Emily: Yeah, no no bad idea.
Don't not a good not a good
Anna: Not an approved weight loss method.
Emily: What are the worms are we talking about today?
Well, look at this guy!
Anna: Yeah, this is one of my favorite specimen.
Emily: Who's this?
Anna: This is a giant leech
So this is the giant Amazonian leech so you can guess where they live. Generally in the wild
they're a little smaller, so this guy lived in a lab and had as much food as he wanted
Emily: And when you say food
I mean, are you putting kibble in its tank?
Anna: No, this one feeds on blood we affectionately call this leech Grandma Moses because she is quite large
Emily: How long did she live in the lab?
Anna: I don't know but there's a very famous picture of a famous leech biologist
with Grandma Moses laying on his arm.
Emily: I you know
I really feel like I've met a
celebrity leech today
and they're part what kind of worm are they?
Anna: They are in the phylum annelida. So
leeches, they're our closest relatives or earthworms. They look a little different
to a scientist because we know certain characters look for namely because they have that blood feeding
nature whereas earthworms are not but one of the things that makes
earthworms and leeches similar to each other is that they are
hermaphrodites so they have both sexes at one time.
Oh, whereas the next closest relatives out the polychaetes
So like your marine worms the bristle worms, many of those are separate sexes.
Emily: How did it how does one collect leeches?
Anna: Depends on which kind of leech you're going for. So my research was with medicinal leeches
that like to feed on humans. That involves going out into
places where you expect to find leeches
So like lakes and ponds and streams
and roll up your pants legs and wade in you make a little bit of movement
you do the leech dances, I like to say
Emily: Is there an actual movement?
Anna: Yeah, you want to make ripples in the water and so the leeches can feel the movement
So if the leech just come up
Emily: So there's choreography to this.
Anna: Yes.
So you've to synchronise your leech dance.
Emily: So you do the leech dance.
Anna: So you both moving at the same time and they both stop
and you wait for the leeches to attach.
Emily: wait, it's like waiting for the bass to drop.
Anna: So then you have to pull one leg up at a time and examine
and see if they're leeches like each leg.
Emily: Really slow?
Anna: Yeah, and of course you're standing in mud and rocks
and you're trying to keep your balance, so it's a very active sport.
Emily: I'm I'm so tempted to try this the next time I'm in a swampy freshwater environment.
Anna: You should come out sometime
I can show you really fun leeches
Emily: Yeah, it will be the leech dance
Anna: Or yoga moves
Emily: This is awesome. So when you talk about the number of specimens that are in the collection
Are they all preserved in alcohol like this, in jars?
Anna: Another way of preserving worms is especially for the very small ones are best shown on glass slides
because of the 12 phyla of worms that we have in our collection here many of them are very small.
Emily: So these are the charismatic megafauna of the worm world.
Anna: Yes, exactly.
Emily: And for that we have the biggest worm I've ever seen in my life
Anna: This is I think the largest worm in our collection.
This is what we call super worm. So this worm was collected in
the Caribbean and
the scientist who collected it
saw a worm coming out of a coral reef if it was really big and he grabbed it
But well a lot of these worms will do is when they feel endangered they will release part of their body.
Emily: Oh my goodness that, it must be like five or six feet long.
Anna: Yes.
Emily: And this isn't even the whole worm.
Anna: No. We don't know how long the part was it got away
Emily: How does the worm have any business being that large?
Anna: Just imagine what it eats.
Emily: So you mentioned that there are 12 different
phyla of worms. How are there
so many different kinds? How are they able to diversify so much?
Anna: Worms in general
these phyla are very old groups in terms of the history of life in the history of animal life. When you're that old
there's many different environments that they've been able to get into and diverse by and
specialized in. So we have worms that live in the ocean. We have worms that live in freshwater
Obviously worms at live on land because they're in the soil like earthworms
even worms that live inside of vertebrates
So just about anywhere you can think about there's probably a worm living there.
Emily: They've been able to colonize
virtually every environment on the planet.
Anna: So there's lots of diversity out there that we haven't been able to collect yet
or that we have collected we haven't described.
Emily: So, do you know how many different described worm species there are?
Anna: So at this point just doing some rough calculations
It seems like there's around sixty six thousand species of worms that are described.
Emily: That are already described sixty-six thousand.
Anna: Right.
Anna: There could be more than
250 thousand species of worms that are waiting to be described what we need more worm scientists.
Emily: There are some we do so many worm scientists. There's that's a lot of work that has to be done.
Anna: Yeah.
Emily: And I think it's so..
Anna: Pretty daunting
Emily: And it's it's well, it's amazing if you think about worm diversity in comparison to like vertebrate diversity.
Like how many mammal species are there? There's maybe eight or nine thousand species of mammals
Just eight or nine thousand and you're talking about a quarter of a million different species
of worms. I think everybody should be a worm scientist
You'll never get all the work done, otherwise
Anna: We need help.
Emily: Yeah, come help Anna.
Here I am leeches,
and then you got stopped.
Anna: and you guys stopped and then
You know to have to pull out one leg and look,
carefully, and see if you can see leeches on it. And if you do then you pull them off.
Emily: Leeches, leeches, leeches.
Anna: Yes, you grab all the leeches.
Emily: This is me at the club.
Boy I like dabbing, is that what people say
It still has brains on it