Today, you’ll learn about a new discovery that explains what causes octopuses to go into a death frenzy when they have kids, how air pollution sensors could help track invasive species, and how fungi could save entire ecosystems.
Today, you’ll learn about a new discovery that explains what causes octopuses to go into a death frenzy when they have kids, how air pollution sensors could help track invasive species, and how fungi could save entire ecosystems.
Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/octopus-death-frenzy-wildlife-tracking-fungi-to-the-rescue
Octopus Torture
Wildlife Tracking
Fungi to the Rescue
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[SFX: INTRO MUSIC/WHOOSH]
NATE: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you’re learnin’ super cool stuff. I’m Nate.
CALLI: And I’m Calli. If you’re dropping in for the first time, welcome to Curiosity, where we aim to blow your mind by helping you to grow your mind. If you’re a loyal listener, welcome back!
NATE: Today, you’ll learn about a new discovery that explains what causes octopuses to go into a death frenzy when they have kids, how air pollution sensors could help track invasive species, and how fungi could save entire ecosystems.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
NATE: Did you know that most species of octopus have their numbers go down after reproducing?
CALLI: I did not know that. Seems a little counterintuitive? Wouldn’t the numbers be going UP if they’re reproducing?
NATE: That would definitely make more sense but, as it turns out, in many species, as an octopus mom's eggs get close to hatching, they stop eating and go into a frenzy of self-destruction, beating themselves against rocks, ripping at their own skin. They’ll even chew up bits of their own arm!
CALLI: Wow. That doesn’t just seem counterintuitive that seems super counterintuitive. Why would they do something that - at least on the surface - would hurt their ability to take care of their babies?
NATE: Ah, that's the million-dollar question. Researchers have been scratching their heads over this behavior for years. Some theories suggest the octopus mother's dramatic death displays draw predators away from the eggs. Others think the mother's body releases nutrients into the water to nourish the little ones. But the most likely explanation, according to Z. Yan Wang, an assistant professor of psychology and biology, is to protect the babies from their own cannibalistic relatives.
CALLI: Wait, octopuses are cannibals?
NATE: They definitely are. If the older octopuses stuck around, they might end up eating all of each other's young. It's like a family reunion gone just terribly wrong. So, the mother’s death protects the baby octopuses from becoming an all-you-can-eat buffet.
CALLI: That paints a picture. But why do these octopus mothers go to such extremes in self-destruction?
NATE: Well, here's where it gets even more interesting. A study conducted in 1977 found that the mechanism behind this self-destruction lies in the optic glands near the octopus's eyes. These glands control the fatal frenzy. If the nerves to the optic gland are cut, the mother octopus abandons her eggs, starts eating again, and lives for another four to six months.
CALLI: So, it's all about the optic glands. But how do those little glands control such dramatic behavior?
NATE: That’s exactly what Professor Wang wanted to know. She and her team found that after an octopus lays eggs, chemical changes occur in the production and use of cholesterol in her body, which, in turn, increases her production of steroid hormones. It's like a biochemical shift that seals her fate.
CALLI: But why would chemical changes happen that make her, like, bash herself on a rock?
NATE: The purpose is still a mystery. Like I was saying, we have some theories like keeping predators away from the eggs. Imagine a mother saying, "Hey, look at me! I'm a delicious meal! Forget about my babies over there!" It's a dangerous sacrifice that protects the next generation.
CALLI: So these chemicals must be pretty powerful.
NATE: Hold on to your tentacles. They found three separate chemical shifts that occur when an octopus mother lays her eggs that are responsible for the octopus mothers' self-destruction. They also discovered that the optic glands start producing more components for bile acids - components that have been shown to dictate the lifespan of some worm species.
CALLI: Lifespan? Like…this discovery could have implications for living longer?
NATE: Absolutely. Like everything, more research is needed. But these findings could lead to a new understanding of the mechanisms behind longevity - and not just for the octopus or the worm.
CALLI: All because octopus moms go bonkers when their babies start to hatch, and researchers wanted to know why.
NATE: Every huge discovery starts with one thing: curiosity.
[SFX: WHOOSH]
CALLI: Air quality has suddenly become a huge deal.
NATE: Not so suddenly if you live in some parts of the country. On the west coast they’ve been dealing with it for years. Wildfires. Pollution. You name it.
CALLI: Totally. In fact, there are millions and millions of air quality monitors around the world. Some of them have been in operation for decades, gathering data on the particles in the air that can be super harmful to us. But it turns out those same pollution monitoring stations have been accidentally collecting another type of sample too. Life.
NATE: Life? Like…are these stations full of tiny villagers, where tiny people harvest grains and live robust lifestyles in miniature?
CALLI: Wow. Let me rephrase. These stations have inadvertently been gathering DNA all these years.
NATE: Whoa! I have a lot of new questions. Like…whose DNA?!
CALLI: All types of environmental DNA, or eDNA as scientists call it, from the surrounding ecosystem can end up in the filters. James Allerton at the National Physical Laboratory in the UK said he read a paper about how scientists had been gathering DNA using air filters, and he was like: holy crap! There are already millions of these filters in continuous operation around the world! Of course I’m paraphrasing. So he teamed up with researcher Elizabeth Clare at York University in Toronto to analyze filters from stations in London and Scotland.
NATE: So did they find some of this eDNA?
CALLI: Not just some. Lots. The samples contained DNA from over 180 different species, including hedgehogs, trees, fish, smooth newts, birds of course, and even arable crops like wheat, not to mention fungi and insects.
NATE: Wow. So…that seems like a big deal, but…I’m not sure why.
CALLI: It’s a huge deal. The thing is, some of these air monitors have not only been in operation for decades, they’ve been archiving their samples for decades. What they potentially have here is a snapshot of local ecosystems all over the world.
NATE: So they can look at what kinds of plants and animals were around when the filters were running to get a kind of biodiversity map. Am I getting that right?
CALLI: Yes, but it’s not just about seeing what was around at a given time, it’s about seeing what’s changed since. They can now detect the rise of invasive species, for example, or the fall of native ones. And if you want to track the success or failure of conservation efforts for some species of butterfly, for example - you used to have to go out and look for it.
NATE: Counting butterflies in the wild isn’t easy, I would guess.
CALLI: Right - but now you can just access the air pollution monitor, scan for DNA, and you’ve got your data right in front of you.
NATE: I feel like I’ve heard about environmental DNA before. This isn’t exactly new, is it?
CALLI: Not exactly. Researchers have been collecting soil and water and other environmental samples to sort through eDNA for a long time. But what they didn’t realize was that these monitors had been doing that work without knowing it for years and years. This could potentially give them an incredibly accurate picture of the world’s changing biodiversity, and that’s a really big deal.
NATE: I do love these kinds of science surprises. It’s like a treasure trove of data.
CALLI: Sometimes the biggest discoveries of all are made in the most unexpected places. You just have to be curious enough to look.
[SFX: WHOOSH]
NATE: I want to take you on an adventure to a super remote island in the Pacific Ocean called Palmyra Atoll.
CALLI: I’ll get my sunscreen! How remote are we talking?
NATE: I’m afraid this might have to be a journey of the mind, because if you wanna go there in person, you head out to Hawaii…
CALLI: …that’s pretty far.
NATE: …and then head about a thousand miles south.
CALLI: Okay. Not exactly a weekend trip.
NATE: Nope. It’s one of the most remote island atolls on the entire planet. And it’s incredible. At least the coral reefs are. Life under the water around the Palmyra is pristine and flush with life. They are the stuff of legends - literally some of the most pristine reefs anywhere in the world.
CALLI: Sounds awesome! So far so good.
NATE: Yes. But I’m not taking you there to go snorkeling. We’re going above ground, where conditions…aren’t so great. Coconut plantations in the 1800s brought in invasive palm trees that wrecked the rainforests, and then the U.S. military made things worse by building airstrips during World War II.
CALLI: Oh gross.
NATE: Right. So several organizations, including The Nature Conservancy and the United States government have done a ton of work to rehab this little Eden. They’ve eradicated the invasive rats, and now they’re trying to bring back the native plants and trees, hoping that they can actually get the rainforest to grow back healthy and strong - which could actually help the coral reef withstand rising sea temperatures.
CALLI: That’s a lot. How’s it working?
NATE: Eh…not so great. But one evolutionary biologist from the Free University of Amsterdam named Toby Kiers thinks there might be a mysterious superhero swooping in to save the day.
CALLI: Don’t tell me it’s Elon Musk…
NATE: …nope. It’s fungi.
CALLI: I mean…some people might say Musk is also a fun guy. No, actually, I don’t know anyone who would say that. But I assume you mean, like, mushrooms.
NATE: Yeah. This isn’t your normal culinary mushroom. We’re talking about mycorrhizal fungi that form partnerships with plant roots. These fungi help supply nutrients to plants in exchange for sugars from photosynthesis. Many native plants depend on certain mycorrhizal fungi species to help them survive. Without their fungal partners, they struggle to grow.
CALLI: I love a good symbiosis story.
NATE: Right. So Kiers traveled all the way out there to collect soil and root samples to see if the right mycorrhizal fungi were present to help restore native trees like the Pisonia tree. So check this out - the Pisonia is an amazing example of why bringing back the forest is so important, because it provides nesting spots for seabirds. More birds equals more guano fertilizer. And that guano nourishes the coral reefs.
CALLI: Everything is interconnected. So…did they find the fungi?
NATE: Initial results look promising. Mycorrhizal fungi seem to be there, especially under native Pisonia trees. They still need to analyze the species to know for sure. But here’s the bigger picture - island habitats are being totally wrecked. These ecosystems hold around 20% of the world’s biodiversity - including many species that literally don’t exist anywhere else on Earth. And islands are some of the most damaged, disturbed ecosystems on the globe.
CALLI: So Palmyra could be an amazing test case.
NATE: Exactly. And to bring it full circle, researchers have had some luck with getting rid of invasive species, and mixed luck bringing back the good native plants, but the work being done on Palmyra might prove that fungi is the magic key that could unlock the restoration of some of Earth’s most damaged - and important ecosystems.
CALLI: That sounds like the morel of the story…
NATE: Is that a mushroom joke?
CALLI: It might be…
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up. Researchers have discovered the chemical reactions that cause octopuses to go into a death frenzy as their eggs get closer and closer to hatching, a behavior that likely wards off predators and other cannibalistic octopuses. The findings could lead to new insights on longevity in other species.
CALLI: Researchers have discovered that air quality monitoring stations already collect and store DNA from plants and animals in the environment, providing a valuable source of biodiversity data that they can now use to track the rise and decline of species and identify new creatures.
NATE: Researchers are exploring whether microorganisms found in soil, like mycorrhizae, could help to restore heavily degraded ecosystems on Palmyra Atoll, one of the most remote islands on Earth. The fungi in the soil may be key to helping the native species thrive again, and Palmyra could be an example for how to restore other islands.