Short Wave - Nudibranchs Do It Better

Episode Date: September 2, 2021

Maddie and Emily get super nerdy one last time as they dive into the incredible world of nudibranchs. Not only are these sea slugs eye-catching for their colors, some of them have evolved to "steal" abilities from other organisms — from the power of photosynthesis to the stinging cells of their venomous predators. These sea slugs are going to blow your mind!You can email Short Wave at [e-mail]. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, everyone. Emily Kwong here with Maddie Safaya. What's up, Duterino? Hey. So if you all haven't heard, it's Maddie's last week on Shortwave. And we have been sharing some of her favorite episodes and the little memories we had making them. Yes, I have been crying and laughing all week. It's been a journey, Emily.

But today, I've got a brand-nuty one for you. my last reported episode on some of the most magical invertebrates in the animal kingdom. Can you guess? With you, it could be anything. It just needs to be maximally slimy and gross. Am I close? Wow, yeah. Closer than I want you to be, honestly.

I don't like that. But yes, we are talking about sea slugs, specifically one big group of sea slugs called nudibes or nudies, if you will. I didn't make it up. If you haven't seen one before, Emily, Google Newtabrackes. Newtabrank. These will actually blow your mind. Here's one of the scientists I talk to Ryan Hewlett, straight up nerding out about them. Like when I think of these colorations and these patterns, like you have polka dots. You have stripes. You have, you know, all shades of colors that I just like don't see that often in other animals. Like honestly, when I think of like very beautiful animals, I think of neuterbranks. Wow. What an endorsement. All right. I'm looking these up.

Look them up. Brinks. Oh, wow. Right? These are some gorgeous technicolor slugs. Is that what I'm looking at? I mean, this purple one looks like it's going to a rave. They might be. They might be. And here's the thing. They aren't just out here looking pretty either. I do think of them as having superpowers. And I think of, you know, some of like the classical X-Men characters who, you know, are able to steal other people superpowers. powers. So, Emily, some nudibranks essentially have the ability to do that, eating up organisms from

their environment and using their abilities for themselves. You mean absorbing the power of your prey and using it for yourself? I am so here for this. Let's go. So today on the show, we dive into the incredible world of neuterbanks, some that have evolved to harness the power of photosynthesis, others that can steal stinging cells from venomous predators and use them for their own defense. It's going to be a solar-powered sting-stealing slug show. Classic Maddie Safaya reporting. This is Shortwave, the Daily Science podcast from NPR. All right, Maddie Safaya, you're taking us on a sea slug odyssey today.

Where do we start? Okay, so like I said, today we're focusing on Nudobranks, a particularly charismatic group of sea slugs. They are remarkably diverse. They live in every ocean and most marine habitats. There are more than 3,000 different species of them worldwide. And Emily, people are like really into them. Do you remember Ryan from earlier?

Yeah, he was pretty hyped on them. Yeah, yeah, yeah. So he's a PhD student at Harvard studying evolutionary biology. But before Harvard, he did his master's studying nudibranx. And once you love nudibranx, you don't just stop loving nudibranx. I live the passion every day, even though like I've been working on other weird critters. Live in the passion, the nudibank passion. He says that some scientists who study nudibranx actually call themselves nerderbranks.

And I love that. When the fandom has a name, you know the passion is real. And I'll be honest, Emily, I was initially drawn to them because some of them are so cool looking. But for me, the amazing thing about Debranx is how they harness the powers of other organisms around them. And that's what I want to talk to you about today. Yeah, this honestly fascinates me. Okay, so earlier you said some of these sea slugs have the ability to co-opt photosynthesis, the process of using light to make food. I know that plants, algae, and some bacteria do this.

But like, I've never heard of an animal doing that. How does that even work? Okay, so you're already on the right track. The key for neuterbranks is something you just mentioned, algae that use photosynthesis to make food, aka photosynthetic algae. Quite a few neuterbanks can do this, but let's walk through one particularly cool example. So there's a neuterank called phyla desmium longus serum. These neuterranks feed on corals, and hanging out inside those corals are photosynthetic algae. Kind of this mutualistic relationship where corals giving them like a nice habitat to kind of hang out in,

and the algae are providing them sort of with like nutrients and things like that. So when the nudibranks eat up those corals, they end up eating that algae too. Now, instead of just like eating all the algae and excreting it, the nudibank stores some of those algae in their digestive gland. And their digestive gland isn't like just in the belly of the slug, like our human intestines. They actually kind of extend up into these finger-like projections called serrata that grow and stretch out from the main body of the slug. And what is interesting is that most of the time

this tissue or this like projection is fairly transparent. And because of that transparency, light is able to enter and actually sort of, you know, hit those algal cells and the algae are able to do what they do really well is to photosynthesize. Whoa. Yeah. So the algae just kind of hang out inside the digestive gland of the neuterang

making food, using light, and producing nutrients the neuterranks can use. Let me get this. Right. So nudie eat the algae. Some of the algae survive and get stored inside the digestive gland. Yeah. And they just keep photosynthesizing.

Yeah. And in Longa serum, the slug that we've been talking about, it is especially good at this. They've evolved these like really big paddle-like serrata. And so they can house these really well-established, thriving communities of algae inside them, hooking up these neuterbranks with nutrients. They're essentially farming these algae inside of their bodies.

That's incredible. Yes, that is how scientists actually describe it. So they really rely on these algae. I mean, scientists have actually starved these neuterbranks for weeks or several months, and they can survive just on the nutrients from the algae. It's a beautiful piece of symbiosis, in my opinion. It is beyond. I mean, could you imagine if we could do this?

You know, like you're running late, no time to eat. I'll just rely on my body's solar power. It's perfect. It's perfect for us. You know, for the gal on the go, you really just like getting that harnessing those algal powers. Just a solar powered gal on the go, Emily. I want this for the future. Okay.

So that's the solar powered nudibrinks. Yes. You've also mentioned that some nudibrinks can steal stinging cells from animals like jellyfish. Yeah. So I talked to Jessica Goodhart about this. She's a postdoc at Scripps Institution of Oceanography at UC San Diego. And I think it's also fair to call her a nerderbrank. It is the most exciting thing I could have imagined doing.

When I was an undergrad, I never even could have possibly imagined studying something like this. And they're just cool ultimately. What a nerda brink. Yeah. And Jessica's whole thing is studying how nudibranx steal parts of a venom-based. filled stinging cell from other animals by eating them. And these neuterbranks eat some pretty gnarly animals. So this includes things like jellyfish.

You can also include things like Portuguese manawar, which are a different kind of Nidarian. There's also anemones, things like hydroids, if you're familiar with those. They don't play, right? And all of those animals have the capacity to fire these little harpoon-like structures called nematocyst. And nematuses are, scientifically speaking, pretty metal. Like, say you, you know, you poke a little jellyfish, for example. What happens is if you touch the tentacles, these structures fire as if they are a harpoon into the tissues of, you know, the other organism. And what happens usually is that there's venom that's released.

That's a mix of a variety of toxins and can cause really severe damage. So this is what most people associate with jellyfish stings. these nematuses are what the nudibank steal. Oh. And you said they get them by eating the jellyfish or whatever? Right, right, right, right. Right? So how does the nudibranch not get stung to death as they try to eat them and, like, harvest their harpoons?

Right. So it seems like a few things are protecting the nudity throughout this process. They use the mucus that they have or that they generate outside their bodies to basically prevent some of the maticus from firing. Now, I should say that some of those little. stinging harpoons do fire. But the nudibrinks have this little cuticle in what is essentially their throat that protects them from those. And so essentially they just like poop out those little fired nematosis. Wow. A shield of mucus and a gut of steel. This is like real superhero behavior. I know. I know it. So they poop out the ones that are fired. But there are some that don't fire.

Either those prevented from firing like we talked about. Yeah, hashtag mucus. Or potentially. something even cooler. Jessica says it's possible that some nematicists that make their way into the slug are kind of underdeveloped. They're not like quite grown-up harpoons yet. And there is some evidence to suggest that what basically happens is that the nematocyst are matyrins are maturing inside of the neuterbring. So the neuterranks are able to create an environment that allow the nematocyst to essentially be prepared to fire. But we don't know for sure that that's 100,000. percent happening. I can't with these creatures. Okay, so where do the slugs then put the little harpoons that they steal? Okay, remember the serrata from the other nudibranks we talked about?

Oh, yeah, those like finger-like projections that kind of come off the body of the slug. Yeah, so these nudibanks have serrata, too, and the unfired nematocyst make their way up there. At the very tip of those appendages is something called the Nidusack. And what essentially it is, is It's just a sack. It's a muscular sack that has a bunch of cells that are the ones taking up the nematocyst. Ah, okay. I get it. So let's say a little fishy comes along, maybe looking for a snack. Basically, the nitousacks, you know, squeeze their muscular structure. So the muscles are squeezed and the nematosis are released. And so the fish basically gets a mouthful of stinging, of stings. And, you know, if you were a fish, you might not. You might not be that excited about that.

Newterbrinks are incredible, Maddie. I know. I think we should start saying dootabrank, you know, instead of dutorinos. Think about it. Think about it. Okay. Brilliant. I'm brilliant.

Okay. If you could pick one of these superpowers, which would it be? The ability to harness photosynthesis from algae or the power of a jellyfish sting. I mean, no, like, not even a question. I would go the photosynthesis route. Like, I love a good symbiotic relationship. Kind of reminds me of us in a way, you know, of the whole shortwave team, leaning on each other to make it through the tough stuff,

protecting each other from the elements, providing each other food when one of us forgot to eat. We've done that. You know, that's real. I will be your symbiotic slug algae any day, but we are really going to miss you. I'm going to miss all of you every single day. All right, dude to brink.

That's the show for today. But we're not done being nostalgic and sappy. So tomorrow we're back with a very, very special send-off for Maddie's last day on the show. Something she doesn't even know is coming yet. I know I'm going to cry. I know that. I know that. This episode was produced by Britt Hansen, edited by Viet Le and fact-checked by IndyCarra.

This is shortwave. The Daily Science podcast from NPA.