Andy Wood: Smell that?
Rachel Lewis Hilburn: Cat pee.
AW: Cat pee.
[WALKING]
Before we even see the clumps of yellow pitcher plants ahead, we smell them.
[MUSIC UP]
Our guide today is Andy Wood, Director of Coastal Plain Conservation Group, and I’m Rachel Lewis Hilburn. And you are in the Wild Coastal Plain of southeastern North Carolina.
AW: It’s not unlike a La Brea tar pit, you know, where a musk ox or a bison gets trapped and that draws in a saber-toothed lion or a bear to feed on it. It gets stuck and suddenly you’ve got a pool of tar loaded with various animals, and so we have that with the yellow pitcher.
RLH: In each episode, we meet a plant or an animal endemic to this biodiversity hotspot – so we can better understand our coastal plain ecosystem and who lives here with us.
Right now, we’re exploring Holly Shelter, a nature preserve and game land in Pender County that boasts tens of thousands of acres -- one of the last great pieces of connected natural area in southeastern North Carolina. That’s because humans are rapidly building all around it.
RLH: These are pitcher plants?
AW: Yellow pitcher plant. And this is a low, wet spot that’s now naturally populated. These weren’t planted. These got here naturally. So they were here already, which is evidence that this was a wetland to begin.
And they’ve just taken over in here, robustly, because it’s a perfect habitat.
RLH: This is a profusion.
AW: They’re thick. And if you tried to dig a hole in there, if you plunged a shovel into that, you’d hit rhizome, the underground stem of all those pitcher plants. They’re all interwoven like fabric. And so that’s a bed of pitcher plants.
RLH: In between the trees -- pond pine, long leaf, loblolly, we’re standing on the edge of what looks like a small pond. The yellow heads of blooming pitcher plants outline the perimeter.
Yellow pitcher plants bloom here in April and May, producing flowers with five, bright yellow, drooping petals.
AW: The flowers, they’re surreal. They look alien. The fun thing about them is when you have a plant in a pot that’s blooming and you’re using it in a program and you’ve got it in your car, suddenly it smells like a cat has relieved itself in your car. It smells like cat urine. It is just not attractive.
You don’t see them often in floral arrangements.
RLH: But if they weren’t quite so foul-smelling, you might. As Andy just said, they look exotic, sort of alien. According to the U.S. Forest Service, they can grow up to three feet tall – with green or sometimes red-veined stems -- long tubes that hold a mysterious and deadly cocktail for their prey. These tubes, or pitchers, are protected on top by a flap or a hood.
RLH: What role do they play in the ecosystem here?
AW: They are apex predators of insects and some spiders, and even snails.
RLH: We walk towards them to get a closer look.
Andy picks up an old, dead plant to show me.
AW: You can see it’s a long tubular stem – it grows as a hollow tube and what happens – the plant secretes something, we think, right here that serves as a draw to ants and wasps in particular. They’ll climb up the stem, drink on this, and as they’re moving around, it’s like walking on a railroad tie – and you have a good chance of falling out to the left or if you fall to the right, you’re going to drop down into this tube, which, in the living plant -- and you can feel it’s fairly smooth and when it’s alive, the inside is covered in loose, waxy cells so the claws on the end of an ant or wasp’s feet can’t get a purchase.
[HORROR SOUNDSCAPE]
As they struggle they’re slowly dropping down into this tube…trying to get away and because it narrows as it goes to the root, the insect gets bound tighter and tighter and it can’t move any much more – it keeps slipping further and further down. Meanwhile the plant is releasing acids and enzymes similar to the contents of our saliva that will slowly begin to digest the insect, after it finally suffocates, having slipped down tight into this tube, screaming and hollering for help the whole time.
It’s really-
RLH: Nooooooo!
AW: It’s harsh.
RLH: No, you’re making that up!
AW: Well, they don’t scream.
RLH: No!
AW: But they’re struggling.
RLH: No! So, my story about that, non-expert, would be–
[HAPPY DRINKING MUSIC]
–the ant or the insect gets drunk, and as he slides down the tube, he loses consciousness.
AW: There is that. That’s what I go with. I’ve long said that they’re drinking this and they get drunk and stumble and fall down in there, so I’m not going to dispute you. That’s a much happier story.
[snicker]
They just fall asleep.
And then get slowly digested by the plant.
That’s pretty rough.
RLH: He picks up another dead yellow pitcher plant. And he points to holes in the tube.
AW: And those are created by a caterpillar that uses this leaf as a place to transform from caterpillar to adult moth.
And, if you squeeze on this…
RLH: He opens up the stem.
[cracking sounds of the dead stem]
You’ll see that it’s loaded with the dried remains of last year’s meals.
It looks like compost. It’s a little ecosystem in each one of these plants. All of this material, this brown, organic-looking material is the indigestible and inedible parts mostly of ants.
So what I’ve just done is just scraped out not even a fingernail’s worth of material on a knife blade and you’re looking at hundreds of ant heads which are not the digestible parts.
The moth doesn’t eat it. The plant can’t digest it. So those are ant heads.
All of this, the bulk of this, is chitinous material: ant heads, thorax parts, bits of leg.
Under a microscope it’s really cool to look at all of these things and see how many different kinds of animals were trapped by this pitcher plant. It might be a dozen or more different insects that got caught.
RLH: And so they’re still identifiable under- you can see their heads.
AW: Because you can see their heads. Yeah, and some of them are not identifiable, but, yeah, there are some that can be. The deeper you go, you’ll find smaller things, obviously, because they got down further, but also you’ll find up near the top -- that’s where the pieces of wasp are found, and flies and daddy longlegs, and things like that, that are drawn to the smell of decomposing, digesting insects.
RLH: Remember Andy’s comparison at the beginning to a La Brea tar pit? The smell of the first group draws the next group of predators. They get caught and drown and the smell of their decomposition draws the next level of predator – and so on. A massive ecosystem in what is, to us, a small plant.
AW: In the living plant, in the living leaf – this—
RLH: And you just picked a dead one.
AW: Yeah, these are all dead. When fire comes through this will all be gone.
This is a roof, of sorts, that covers the entrance, the top of the opening –
RLH: That’s the hood we described earlier.
AW: And, so when it rains, rain hits that roof and is shunted away because if rainwater gets into this tube, the plant’s just going to fall over. It can’t stand up filled with water.
Unlike its cousin the purple pitcher plant, and it’s interesting that there are no purple pitcher plants in here, it’s a more low-growing pitcher and its opening is exposed to the air because its trap, its phytotelma leaf pond, fills with water and that water is what drowns its prey.
So insects drawn to the purple pitcher plant leaf, they fall into the trap, hit rainwater with very little surface tension, they sink and drown and then get digested by acids and enzymes produced by the plant but probably more aided by other things that live in that water – bacteria, protozoans and mosquito larvae that feed on that drowned insect.
And then those bacteria, protozoan, and mosquitos produce waste, ammonia-rich, that gets converted by more bacteria into nitrite which then gets converted to nitrate as a source of nutrient for the plant.
Which absorbs the nitrate right through the leaf wall. Which is kind of weird because usually plants get nutrients from their roots, but in the case of pitchers, they get it from roots but they also supplement by getting nutrients through their leaves.
Other plants do that, too, but it’s really cool with pitcher plants: flytraps, butterwort, bladderwort.
RLH: Yep, those are all carnivorous plants – all endemic to the southeastern coastal plain – and we’re about to find some of these others.
AW: This is not a friendly place to insects.
RLH: We haven’t yet addressed the most famous carnivorous plant: the Venus Fly Trap – also endemic to North and South Carolina – even though it’s since been introduced in other states. The Fly Trap has been a threatened species – partly because it was a high-value target for poachers.
But Andy Wood says the real danger to the Venus Fly Trap today is habitat loss thanks to development.
Its official status, though, recently changed. In late July 2023, the U.S. Fish and Wildlife Service announced that because the Venus Fly Trap is not facing an imminent threat of extinction now or in the foreseeable future, it no longer warrants listing under the Endangered Species Act (ESA). In the state of North Carolina, though, the flytrap is still considered a threatened and protected species, and it is still a felony to poach them.
AW: Poaching was, historically, conducted by subsistence families around Holly Shelter, Pender County, and it was primarily an African-American community that were enlisted by growers – plant growers - especially in Holland who would pay them pennies per plant to collect flytrap. And this goes back decades, many decades, before it was illegal to poach.
But even after it became illegal to poach, these growers from Holland and other areas would still pay good money for flytraps.
But back in the 90s, the poachers were aging out. They were in their 60s, 70s, and 80s. And it turns out, their kids did not want to inherit the tradition. And so poaching fell by the wayside because it fell out of favor with the families who originally did it.
RLH: Back then, says Andy, they would fill up burlap sacks with hundreds of flytraps they could find in just a few square feet.
AW: So they can pluck out thousands of plants in a morning.
Now the big poaching issue in Holly Shelter is for reptiles and amphibians. People come in here when it’s a warm, rainy night, they’ll cruise this road when the gates are open, looking for snakes.
RLH: They’re dealers in the black market pet trade, says Andy, from all over the United States.
And they get what kind of snakes?
AW: Eastern king snake, mole king snake, southern pygmy rattlesnake, timber rattlesnake, rat snakes.
RLH: Some of those are venomous snakes. Why? Why venomous snakes?
AW: That’s all the more appealing because of the risk. A pair of pygmy rattlesnakes, especially the red phase that we have here, is worth many hundreds of dollars, maybe a couple of thousand dollars. A healthy eastern chain king snake might be worth fifty bucks. A red phase mole king snake might be worth a couple of hundred dollars.
Somebody could come through Holly Shelter and collect a thousand, two-thousand dollars’ worth of snakes in one night.
RLH: Even that kind of poaching isn’t as profitable as it used to be. He just doesn’t see as many snakes as he used to see in Holly Shelter.
AW: Yeah, Holly Shelter’s getting hammered and continues to get hammered, but the Wildlife Commission realizes that. They’re beefing up their enforcement when they can.
RLH: But resources are limited.
There’s one more carnivorous plant here in Holly Shelter that we have yet to meet.
The Dwarf Sundew.
AW: And you can see it’s in bloom. So you’re here just in time for sundew bloom.
RLH: How do they catch their prey? Well, the sundew uses as a combination of flytrap and butterwort strategy.
AW: This is an active predator. When a tiny ant, thrip, or other insect touches – if you look really closely, you’ll see each pad is glistening. Those are dozens of little stalks with a tiny droplet of glue at the end of each stalk, so when an insect bumps into them and vibrates the stalk, it sends an electrical impulse down that stalk to the leaf.
And that stimulates nearby stalks to fold toward whatever caused that disturbance.
And in a couple of the different sundews, and there’s different species, that one, when you look at its pad, you’ll see the middle of the pad has very short stalks with little droplets of glue. But on the rim are long stalks. So when something touches it, the long ones fold in, and then you’ve got the short ones. That insect is suddenly wrapped in all of these little tendril-like, almost like an octopus, and secretes acids and enzymes and digests the—
RLH: And it has to be really tiny insects because that -- I mean, your fingernail is bigger than that collection of leaves.
AW: Right. And there are insects that are a millimeter in size. Thrips -- I’ve mentioned a couple of times is a common one, but springtails and other little, tiny insects smaller than a no-seeum, which is a little, tiny biting fly. These are tiny, tiny insects.
Another butterwort – violet butterwort…
Wow, I have not seen this many violet butterwort here. This is a great year. Spreading beautifully.
RLH: We’re walking across what looks like a pretty nondescript open field. It’s actually a power line corridor, which is maintained with heavy equipment. But if you look more carefully, you can see that there are clumps of small violet butterworts everywhere.
I try to avoid stepping on them.
We also see Venus flytraps – which often surprise people by how small they are. You have to know where and how to look for them, because they’re so tiny.
What do the flytraps eat?
AW: A lot of ants, big red ant, small wasps, usually not many flies. That’s just what it got named. But small insects like that, even snails. We have small terrestrial snails.
RLH: Andy is pointing to the violet butterwort.
AW: When you look at the leaf, it’s a rosette of leaves curled on the edges and when tiny, tiny ants come across or thrips or other tiny insects–
SPOOKY MUSIC
–when they walk across that leaf, there are glands on the surface of the leaf that secrete a glue-like substance that mires the legs of the insect, and as the insect struggles, it’s sending electrical impulses to the plant’s leaf that secret more of that glue, gluing the insect and then drowning it, kind of like in saliva, and it digests the soft parts of the insect.
RLH: Inches away, we see a few purple pitcher plants. Its upright pitcher-shaped leaves are open to collect rainwater – unlike the yellow pitcher plant which has that protective hood. Andy describes the leaves of the purple pitcher as making a vase-like rosette.
He pulls out a syringe to suck out liquid from the inside of the plant. He puts a few drops of the liquid on a slide and hands me what is basically a small, portable microscope.
RLH: So what is all of that?
AW: That is the digestive remains -- this is the pot licker out of a purple pitcher plant leaf – I’m trying to find a safe spot to stop, put my feet…
RLH: So you just took what was in his stomach – what he was eating –
AW: I just -- I didn’t irrigate its stomach. I did draw from it.
RLH: Is he going to have to eat a bunch more?
AW: I’m going to put this back. But what I wanted to catch…
RLH: He puts the liquid back into the plant’s stem.
Then he drops some liquid from another pitcher plant onto the deep well slide viewer – that small, portable microscope, and hands it to me.
AW: Those are all ant heads.
RLH: Yes! And there’s a – there’s a—
AW: You see that?
RLH: There’s a – a – a—
AW: Midge. Larvae. I know. That’s what you wanted to say.
RLH: Yes. What – what’s a midge?
AW: It’s a relative – it’s a fly, related to mosquitoes. Doesn’t bite.
RLH: It looks like a worm. It’s in there eating.
AW: It’s the larvae and it is eating protozoans and bacteria and digested insect parts and pooping out, again, ammonia, gets converted by bacteria to nitrite, nitrate, and the plant is the benefactor.
RLH: The part of the plant that Andy is drawing from, the phytotelma, is a small, water-filled cavity in a terrestrial plant. He explains what we’ve already been seeing – that the water inside the plant is its own habitat – its own ecosystem. Even within one plant, each stem has its own ecosystem and none of them are identical.
RLH: What are you looking for?
AW: Mosquito larvae but of a very particular mosquito…This is your highlight of the day –
RLH: [gasp]
That’s mosquito larvae?
AW: And a pupa –
RLH: So, what? So the thing that has the giant head…
AW: That’s the pupae about to transform to an adult.
RLH: And is the adult the longer, spiny thing?
AW: No. That’s the larvae. The adult is a very tiny mosquito that eats nectar. It doesn’t draw blood.
RLH: The mosquito larvae looks like a long, spiny worm – it’s almost shrimp-like, actually. And sitting at one end of its body, seemingly way out of proportion in size, is what looks like a very large bobble-head.
AW: And that is the southern purple pitcher plant mosquito.
RLH: It’s specific to the southern purple pitcher plant?
AW: Specific.
RLH: It doesn’t-
AW: It doesn’t draw blood. It pollinates flowers, as do most mosquitoes. Most mosquitoes are pollinators. Only a handful suck blood. And of that handful, it’s only the female that sucks blood as a nutrient source for her eggs. Male mosquitoes don’t bite. They don’t even have a piercing mouth part and don’t suck blood. Male mosquitoes don’t bite. They don’t even have a piercing mouth part.
So when we wage war on mosquitoes, we’re killing more than half of the ones we don’t need to worry with.
Mosquito spray kills all arthropods – not just mosquitoes. So if you’re wondering where have all the lizards gone? Where have all the tree frogs gone? Where have the birds gone? Do you use mosquito spray? You’re starving them.
And you’re killing this guy which has nothing to do with us. They’re just going to go out and pollinate flowers, and then come dump eggs in these pitcher plants.
Yikes.
RLH: On the way out, we pass by, once again, that first small pond we encountered – the one surrounded by yellow pitcher plants. Andy points to a hybrid pitcher plant.
What is that guy we’re hearing?
AW: A southern leopard frog.
LEOPARD FROG SOUND
So we have two bladderworts, yellow, purple, and rehderi pitcher plants, flytrap, and butterwort.
That’s seven carnivorous plants we’ve identified.
All in this one little area. None of this is planted. This just naturally came up in here.
RLH: We see some fish swimming under the surface.
AW: Those are mosquito fish right there. They look just like a guppy. So they’re eating all the mosquito larvae.
RLH: So that’s why we’re not getting eaten by mosquitoes right now.
AW: Correct. Correct.
RLH: Maybe nature knows what it’s doing.
Thanks, as always, to Andy Wood of Coastal Plain Conservation Group.
And thank you for joining us.
I’m RLH in the Wild Coastal Plain.
