Anal Teeth And Deadly Farts: The World Of Invertebrate Butts

FLORA LICHTMAN: For the rest of the hour, we are staying with bug bottom’s. Believe it because this week scientists have a special festival that turns a spotlight towards critter cabooses. Here to tell us more is SciFri producer Dee Peterschmidt.

DEE PETERSCHMIDT: Hey, Flora.

FLORA LICHTMAN: Hello.

DEE PETERSCHMIDT: Hello. So this– so it’s called Inverte Fest, and the inverte is the invertebrates. That’s what it’s known as now. But when I found out about this a few years ago, it was called Invertebutt Week.

And so the idea behind this whole festival is to just take the spotlight just for a second away from the vertebrates, the spine havers of the world, the cute dolphins, the birds, the capybaras, the puppies–

FLORA LICHTMAN: Yeah, they get all the attention.

DEE PETERSCHMIDT: They do. They’ve gotten too much spotlight. It’s time to move that over to the bugs and the slugs and the creepy crawly insects. And this group is like, hey, the invertebrates of the world, they deserve some love, too, and specifically their butts deserve this love.

FLORA LICHTMAN: Why butts?

DEE PETERSCHMIDT: Well, so for mammals, for vertebrates, yes, our bodies are like a bit different from each other, but largely they behave the same. All of our butts essentially have the same function. We have largely the same digestive systems.

FLORA LICHTMAN: It’s like a one butt fits all for vertebrates.

DEE PETERSCHMIDT: Exactly And that is not the story at all with invertebrates because they’ve had all these branches of evolution over the years and they’ve all just developed different uses for their butts, not just for excreting. Just like the wasp story we were just talking about of the wasp trapping its prey in its butt, that sounds like a unique and weird instance and maybe a one off, this happened millions of years ago, that is not the weirdest thing you’re going to hear for the rest of the hour.

I talked to four or five people for this, and I was just constantly getting new butt fact, new butt fact, one after the other. And we really just wanted to share that story again with our audience this week.

FLORA LICHTMAN: Let’s hear it.

DEE PETERSCHMIDT: A few weeks ago, we saw a tweet that caught our attention. Do you mind reading the tweet that you sent out back to me?

MAUREEN BERG: Hold on a second. Let me get it up. Hello, does anyone know of any animal that has a few butts, more than one but fewer than 100? And I’m generally talking butts as the anus. But I’m open to other interpretations.

DEE PETERSCHMIDT: That’s Dr. Maureen Berg, a scientist at the Joint Genome Institute at Berkeley National Lab.

[MUSIC PLAYING]

You probably aren’t sitting around thinking about animal butts, but Maureen is a part of a group of scientists and illustrators who think about them a lot. She got her start in invertebrate biology, and invertebrate butts or invertebutts have become one of her passions. She’s even given public talks about them.

MAUREEN BERG: Now I’m known as the invertebrate butt girl on Twitter, so anytime any new animal butt thing comes up, I always get tagged in these. It’s just a standard procedure at this point. Even though I do no research in this field, I’m just once again– I’m just the loudest person about this.

DEE PETERSCHMIDT: Yeah, how do you feel about that– of that being your calling card now on Twitter?

MAUREEN BERG: I’m honored honestly. It’s–

DEE PETERSCHMIDT: So now people tag her in tweets when certain discoveries are made.

MAUREEN BERG: There’s a recent worm that was discovered that has hundreds of butts.

DEE PETERSCHMIDT: That worm, rhinocyllus multicaudata, isn’t like most worms. Its body segments and branches out at multiple places, looking more like a connected series of cracks in a dried up riverbed than a traditional worm. And at the end of each of these dozens of branches is an anus.

ROSEMARY MOSCO: I’m always looking for comic fodder, and that one wrote itself.

DEE PETERSCHMIDT: Turns out Maureen isn’t the only one fascinated with invertebrate butts on Twitter.

ROSEMARY MOSCO: I thought, oh my goodness, I have to do a comic about an animal with a zillion different butts.

DEE PETERSCHMIDT: Science Illustrator Rosemary Mosco put together a chat group, appropriately named Butt Chat, and invited other butt enthusiastic illustrators and scientists. What were your initial reactions to just being involved in this project?

AINSLEY SEAGO: Oh, complete lack of surprise.

DEE PETERSCHMIDT: Dr. Ainsley Seago, the curator of invertebrate zoology at the Carnegie Museum of Natural History in Pittsburgh, was one of the researchers who got invited to this butt chat. And like Maureen, she’d also given a talk about bug butts before. She started a small document with some of her favorite butt facts, threw it into the chat, and the other members started adding to it.

ROSEMARY MOSCO: I think at one point, I said, oh no, we’ve opened Pandora’s Butt because there were so– there were so many different pieces of information flying in this chat.

DEE PETERSCHMIDT: The group decided they’d team up and use their combined science and illustration powers for good by making comics about the back ends of the back boneless. They’re calling their celebration Invertebutt Week like Shark Week or Cephalopod Week but for invertebrate butts.

AINSLEY SEAGO: It’s just a chance for some people who do science communication to do the silliest thing that they can possibly think of. We love talking about this stuff. Sometimes you get really tired of only covering the depressing news or only covering the extremely technical details, and this is something that’s both educational and delightful frankly.

DEE PETERSCHMIDT: So we’ve got lots of information but not an answer to the big question. What even is a butt?

MAUREEN BERG: There’s been discussions on science Twitter in the past about what is a butt. Is it just the back end of an animal, or is it like the anus?

DEE PETERSCHMIDT: Some purist researchers are a little anal about this and believe that the word butt should only be used when referring to fleshy buttocks. Maureen and Ainsley have more generous views on this.

AINSLEY SEAGO: You got one end where food comes in and one end where poop goes out. That second end is, in my personal definition, the butt. It does get challenging when you think about questions like if a bug wore pants, would it wear them like this or like this. But I think we can conclude that what would be an insect morphology terms refer to the abdominal apex is. I would say with zero ambiguity the butt region.

MAUREEN BERG: So, yeah, context is very important on how you define it, but I’m flexible on definitions.

DEE PETERSCHMIDT: And for a bit more context, we have to go back hundreds of millions of years ago to the Earth’s oceans. Most animals back then didn’t have what we think of as a butt. Most just had a single multi-purpose hull for eating and excreting. The descendants of some of these animals are still with us like coral and jellyfish, but as you might imagine, that one road setup had some serious drawbacks.

MAUREEN BERG: And so the idea with that is can only eat and then you digest your food and then you can get rid of your waste. Whereas with us as humans, you can continue to eat as you’re digesting. You don’t need to wait for your whole digestive system to clear out before you eat again. So the whole even concept of evolving an anus allows you to basically eat and digest at the same time. So it’s a little bit more efficient.

DEE PETERSCHMIDT: The evolutionary marvel of the digestive system and subsequently the anus was a big deal for life on Earth. Animals got more out of their meals, bodies lengthened and grew bigger, and developed better ways to move around like swimming, walking and flying rather than say just existing, floating in the water like a jellyfish.

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What’s a butt that you think that more people should know about?

MAUREEN BERG: My favorite animal butt to talk about is the sea cucumber butt just because it does a lot of weird things. It’s not just one weird thing that does a lot. A lot of sea cucumbers’ butts act as homes for other animals. You have the fish. You have crabs. You have a lot of things that live in the butt.

And because maybe you don’t want just any animal living in your butt, a lot of sea cucumbers have anal teeth to prevent certain animals from inhabiting their butt essentially. Because what some will do is they’ll get into the butt and they’ll start munching and gnawing on the gonads and stuff, which is also obviously bad. So they have it all. They have eating, breathing, defense, apartment building. They have it all, and I really admire it.

DEE PETERSCHMIDT: It would get the most versatile butt award.

MAUREEN BERG: Exactly.

FRANZ ANTHONY: I want to talk about the face mite. The best part about them is that they don’t have butts.

DEE PETERSCHMIDT: Franz Anthony is another science Illustrator working with Rosemary on the project.

FRANZ ANTHONY: The problem when someone doesn’t have belts is that they can’t poop, so throughout their life, their body just gets longer and longer as their poop accumulates inside. And then once they die, they just burst open, and then the mite poop is basically all over people’s faces. And I think that’s really, really fun.

DEE PETERSCHMIDT: And I don’t like to pick favorites, but Ainsley’s preferred butt might be mine now, too.

AINSLEY SEAGO: One of my absolute favorites is the neuropteran family berothidae.

DEE PETERSCHMIDT: They’re a type of lacewing, small insects with large, clear wings, and their larvae live in termite mounds, which is a pretty dangerous place to grow up. Termites are essentially soldiers. They’re territorial and dangerous, and they don’t want any intruders in their home.

So how do these seemingly defenseless larvae defend themselves when termites approach them?

AINSLEY SEAGO: They turn around and wave their butt in its face and release an invisible but powerful gas that knocks out the termites almost instantly. So they’re essentially farting them to death as a form of defense. And it’s just one of the most beautiful things of that nature has come up with in her infinite wisdom.

[MUSIC PLAYING]

That’s the central thesis of invertebutts week, which is let there be joy. It’s OK to have yourself a secret little chortle at an insect that’s farting another animal to death. That’s pretty great.

DEE PETERSCHMIDT: I wanted to end on this question, which is why should we care about butts. I’ll take my answer off the air.

[GIGGLING]

ROSEMARY MOSCO: Listen, I don’t think that butts are necessarily the most important thing going on right now in society, but I think that butts are something delightful to think about and looking at one particular body part of an animal can be a way to look at an entirety of an animal and look at the way that it experiences the world.

FRANZ ANTHONY: Yeah, I think butt in general it’s just really funny because it’s really accessible. Even kids understand it. So it is a gateway for kids to understand bigger concepts.

ROSEMARY MOSCO: And adults, too. I think adults are already so excited about anything goofy and butt related. So I think we all need to hop aboard the butt train and, yeah, ride it to science town.

[LAUGHTER]

I’m so sorry.

[MUSIC PLAYING]

DEE PETERSCHMIDT: Like I said earlier, Invertebutt Week is now going by Inverte Fest, and you can join that party on social media through the Inverte Fest hashtag. We also have official illustrations from Rosemary and Franz and others on our site that you can check out. That’s at sciencefriday.com/butts.

For Science Friday, I’m Dee Peterschmidt, national butt correspondent.

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