Speaker 1: Hello, and welcome to Stuff to Blow Your Mind. My
Speaker 1: name is Joe McCormick, and today we are bringing you
Speaker 1: an episode from the Vault, an older episode of the show.
Speaker 1: This one is called do Ants Make Traps? It is
Speaker 1: about exactly that question, whether ants the insect build traps.
Speaker 1: This originally published January twentieth, twenty twenty two. Hope you enjoy.
Speaker 2: Welcome to Stuff to Blow Your Mind, a production of iHeartRadio.
Speaker 3: Hey, welcome to Stuff to Blow your Mind. My name
Speaker 3: is Robert Lamb.
Speaker 1: And I'm Joe McCormick, and today we're going to be
Speaker 1: talking about traps. I think I've mentioned this in some
Speaker 1: Weird House Cinema episodes, but for some reason, ever since
Speaker 1: I was a little kid, I have always loved movie
Speaker 1: scenes where the protagonists build a trap to use against
Speaker 1: the villain or the monster. I remember, like Home Alone
Speaker 1: when I was a little kid, that whole sequence was great.
Speaker 1: It sort of expands to fill my whole childhood impression
Speaker 1: of what the movie was. And if you go back
Speaker 1: and watch it as an adult, it's kind of weird
Speaker 1: that it's only like fifteen or twenty minutes of the runtime.
Speaker 3: In Home Alone. Yeah, yeah, yeah, it does seem like
Speaker 3: that's the main thing I remember. Yeah, they the traps,
Speaker 3: the traps, and certainly people feel certain nostalgia for them.
Speaker 1: My heart swells at the thought of a nail going
Speaker 1: into Daniel Stearn's foot. But also, yeah, I remember other ones,
Speaker 1: like you know, Arnold Schwarzenegger builds a bunch of traps
Speaker 1: and predator. But like, this wasn't just when I was
Speaker 1: a kid. It still works on me. I remember there
Speaker 1: was a sequence I just loved in the more recent
Speaker 1: horror movie It follows where the characters build a trap
Speaker 1: for the last year.
Speaker 3: Yeah, that's right, that is very They have a very
Speaker 3: much a kind of home alones setup that they do there.
Speaker 3: Of course, it's not only the heroes that have traps.
Speaker 3: I always love a good villain trap as well, especially
Speaker 3: the trap door. And the trap door sequence is always
Speaker 3: a lot of fun, you know. Be it something like
Speaker 3: in Lynn Labyrinth. I love the trap when the trap
Speaker 3: door springs on our hero and that. But actually Tomorrow's
Speaker 3: Weird House Cinema also has a fun trap door sequence.
Speaker 3: Oh yeah, so look forward to that. Well.
Speaker 1: Yeah, on side of the protagonists getting through traps set
Speaker 1: for them, another one of my favorite movie sequences as
Speaker 1: a child was the beginning of Raiders of the Lost Art.
Speaker 1: Oh yeah, and when INDI's going through all the traps,
Speaker 1: something about it is just like, deep in the brain,
Speaker 1: it's very satisfying.
Speaker 3: Wall to wall traps. Yeah, that's that's a great sequence
Speaker 3: as well. And all of these are great sequences in
Speaker 3: spite of the fact that when you when you can,
Speaker 3: when you really think long and hard about any of
Speaker 3: these scenarios, you know, the cracks definitely show would all
Speaker 3: of these traps still be working in this ancient ruin
Speaker 3: that Indiana Jones finds himself in. I don't know, it's
Speaker 3: a hard argument to make there, right.
Speaker 1: How did the spring trap operate by you sticking your
Speaker 1: hand through a shaft of light when it was made
Speaker 1: like thousands of years ago?
Speaker 3: Yeah, Or you know, if it's duke and predator, like,
Speaker 3: how does he how does he make this super powerful
Speaker 3: compound bow just in the space of a few hours
Speaker 3: on an afternoon in the jungle.
Speaker 1: That's just standard survival training.
Speaker 3: I mean, and all these other various e Wok traps
Speaker 3: that he builds didn't didn't you go to that camp?
Speaker 3: Did I build a bow like that at a cat camp. No,
Speaker 3: I think we sharpened sticks, you know, that would be
Speaker 3: that would be more believable. Right, he makes a spear, Yeah,
Speaker 3: to battle.
Speaker 1: That's most of the way there.
Speaker 3: Yeah, But you know, I think it probably speaks volumes
Speaker 3: for humans to be you know, to be said all
Speaker 3: of this about traps, and especially about you know, loving
Speaker 3: these cinematic treatments of traps, because because what are traps? Ultimately,
Speaker 3: very broadly speaking, they're clever, tactical and or technological innovations
Speaker 3: that level the playing field against predators, against prey, and
Speaker 3: even against fellow humans. Traps are the sort of things
Speaker 3: that humans have been up to since prehistory. So of
Speaker 3: course we love traps, and of course we admire things
Speaker 3: like traps that we find in other species.
Speaker 1: Right, So today we're going to be focusing on some
Speaker 1: allegations of insects with the ability to build traps, specifically
Speaker 1: ants that do things that may in fact be biological
Speaker 1: evolutions that allow them to trap prey. Now, there are
Speaker 1: some other animals that I think we could say more
Speaker 1: more clearly and famously create traps. I think the obvious
Speaker 1: example here would be spiders.
Speaker 3: Yes, yes, spiders are the trap builders par excellence. You know,
Speaker 3: there are no finer trap builders in the animal Maybe
Speaker 3: you could make a case for human beings, but personally
Speaker 3: I'm not in favor of that. I think web building
Speaker 3: spiders especially are just such highly evolved trap masters. Every
Speaker 3: detail of their anatomy and behavior enhances their trapping ability,
Speaker 3: and the trap is very much an extension of their
Speaker 3: own bodies in so many ways. And we've covered this,
Speaker 3: and we've covered spiders in general numerous times in the
Speaker 3: show before, and we'll likely keep coming back to them.
Speaker 3: But yeah, the spider, the spider is the trap maker.
Speaker 3: There's nothing else that the spider really does. Anything else
Speaker 3: it does the web building spider is going to do
Speaker 3: in close proximity to the web that it has built.
Speaker 1: Yeah. Another example that's come up before, I think in
Speaker 1: our Sarlac episodes was the ant lion.
Speaker 3: Yes. Yeah, this is a case where we have predatory
Speaker 3: larvae that in some species of antlon anyway, set up
Speaker 3: at the bottom of sand pits that they dig, ready
Speaker 3: to lack shout at anything that disturbs their grains and
Speaker 3: you know, ventures down into the trap. Again, not all
Speaker 3: ant lion species dig trap pits, but some of the
Speaker 3: most famous ones.
Speaker 1: Do I remember. One of the great things we learned
Speaker 1: about the ant lion was that, like you say, it
Speaker 1: is the ones that make traps. It is just the
Speaker 1: larval period of their lifespan, their life cycle that they
Speaker 1: make the traps. Then they later metamorphosed into another form.
Speaker 1: But while they're in that larval stage, I think at
Speaker 1: least some of them never poop. So yeah, yeah, catching
Speaker 1: ants and eating them and just like waiting, and it's
Speaker 1: like if you had to wait until you turned eighteen
Speaker 1: to poop.
Speaker 3: We'll go back and listen to that Sarlac episode if
Speaker 3: you'd like to hear more about the ant lion. There's
Speaker 3: also the species of creature known as the worm lion,
Speaker 3: and this is unrelated to the ant lion. It's just
Speaker 3: a matter of convergent evolution that he ends up utilizing
Speaker 3: largely the exact same method again when it's a larva,
Speaker 3: though the pit itself in this case is generated via
Speaker 3: a slightly different method, so it digs its pit in
Speaker 3: a slightly different method, but it still consumes its prey
Speaker 3: in the same manner.
Speaker 1: But for me, at least, if you ask me to
Speaker 1: make a list of non human animals, that make traps.
Speaker 1: I could obviously go spiders. I would have thought of
Speaker 1: the ant lion, maybe by association the worm lion. But
Speaker 1: there before I was reading up for this episode, I
Speaker 1: think I would have drawn a blank. I wouldn't know
Speaker 1: what to go to next.
Speaker 3: Yeah, and part of it comes down to just how
Speaker 3: are you going to going to define a trap? For example,
Speaker 3: Here's here's an interesting potential example we can discuss that
Speaker 3: I read across read about when I was reading Gilbert
Speaker 3: Waldbauer's How Not to Be Eaten, which is largely about insects,
Speaker 3: but there's a part where the author is discussing the
Speaker 3: burrowing owl. So these are small birds native to the
Speaker 3: Great Plains in southern Florida. I think they're about the
Speaker 3: size of a robin. I'm to understand that, you know,
Speaker 3: the small, little little guys. But they make their home
Speaker 3: in burrows that they did themselves. And one of the
Speaker 3: interesting things that they do in addition to this, if
Speaker 3: this wasn't you know interesting enough already, is the burrowing
Speaker 3: owl will scatter horse or cow dung around the entrance
Speaker 3: to their burrows. And then, you know, times before European contact,
Speaker 3: this would have probably been bison dung, and the dung
Speaker 3: does seem to be important because if researchers remove the
Speaker 3: dung from the vicinity, the birds will just the bird
Speaker 3: will just go out and obtain more dung and place
Speaker 3: it in the vicinity. So it seems to be doing
Speaker 3: this intentionally. The theory is that they place the dung
Speaker 3: to bait dung beetles. So they put the dung out,
Speaker 3: dung beetles come, And indeed researchers have been able to
Speaker 3: tell that the owls eat ten times more dung beetles
Speaker 3: than usual when the dung is out.
Speaker 1: Ah. Well, this will in fact mirror one of the
Speaker 1: two examples of potential ant trap making that I want
Speaker 1: to talk about later.
Speaker 3: Yeah, I mean it's but this is a great example.
Speaker 3: It's certainly clever. I like it. But it kind of
Speaker 3: forces us to ask the question of a trap, like
Speaker 3: what is a trap? Is it merely baiting a trap?
Speaker 1: That is a good question, yeah, because and how much
Speaker 1: does the trap structure have to be separate from your
Speaker 1: body in order to recount as a constructed trap? And
Speaker 1: how much does it have to how much work does
Speaker 1: it have to do for you?
Speaker 3: Yeah? And at what point does an animal's behavior stop
Speaker 3: being a trap and just become sneaky behavior, sneaky tactics,
Speaker 3: or simply ambush predation, because obviously there are plenty of
Speaker 3: examples of ambush predators on land and in the sea,
Speaker 3: and these include everything from well, the trap door spider
Speaker 3: for one, which I think is definitely a case of
Speaker 3: building because it's an ambush predator, but it builds a
Speaker 3: silk hinge trap door to aid in those ambushes.
Speaker 1: Right, so the trapdoor hides it. I think you could
Speaker 1: count that as like infrastructure necessary to constitute a trap.
Speaker 3: Yeah, yeah, I think that, Yeah, definitely with the trapdoor spider.
Speaker 3: But then you also have just various camouflage predators, including
Speaker 3: things like frogfish, praying mantis's, chameleons, and more, which are
Speaker 3: not building anything. They're not altering their environment, but they've
Speaker 3: evolved to look like a part of their environment and
Speaker 3: they have the you know, often tremendous abilities of camouflage
Speaker 3: that enable them to quickly ambush something that they want
Speaker 3: to eat.
Speaker 1: Okay, that probably doesn't That doesn't really seem like a
Speaker 1: trap to me, because they're just evolved to look that way,
Speaker 1: and they they do the actual hunting themselves.
Speaker 3: Right, And then of course you have various birds and
Speaker 3: cats and big cats even that are just very stealthy,
Speaker 3: that are just very good at not being observed by
Speaker 3: the things they want to kill. So I was reading
Speaker 3: a little bit about this in Douglas j Imlin's excellent
Speaker 3: book Animal Weapons that have referenced on the Show before,
Speaker 3: and he points out that creatures such as this generally
Speaker 3: depend on quote, a quick strike weapon that immediately incapacitates
Speaker 3: its victim. And of course these bioweapons might be enhanced
Speaker 3: by special features, such as in various deep sea ambush
Speaker 3: predators a bioluminescent lure, which again is not something they
Speaker 3: have created or engineered out of their environment, but it
Speaker 3: is a part of their body. So when we come
Speaker 3: back to this idea that what it needs to be
Speaker 3: something that's built, it needs to be something that's engineered,
Speaker 3: or just a hole dug in the ground, even we
Speaker 3: come back to that same question, well, why don't we
Speaker 3: find more of this? And I actually found an interesting
Speaker 3: paper title out there, Why are pitfall Traps So Rare
Speaker 3: in the Natural World? By G. D Ruxton and MH. Hansel,
Speaker 3: And it appeared in evolutionary ecology in two thousand and nine.
Speaker 1: Interesting question.
Speaker 3: Yeah, So the authors here point out that in order
Speaker 3: to lay a trap, you generally need either advanced cognitive
Speaker 3: powers as with humans obviously, or you need specialist self
Speaker 3: secreted materials as with spiders and cattisfly larvae, thing which
Speaker 3: the catasi fly larvae use that their their secretions to
Speaker 3: create a net like even meshed trap like a silk trap,
Speaker 3: in order to filter catch their prey.
Speaker 1: That makes sense. So humans can create all kinds of
Speaker 1: traps because we have, you know, cognitive powers that allow
Speaker 1: us to imagine what could be done. How you know,
Speaker 1: other materials in the environment could be repurposed to passively
Speaker 1: ensnare or kill prey animals and spiders and stuff. That's
Speaker 1: just the trap you could almost say, is a part
Speaker 1: of their body. Even though the web is a built thing.
Speaker 1: They revolved to secrete the silk for the web out
Speaker 1: of their bodies, and they have very instinctually driven behaviors
Speaker 1: for how they extrude that silk wear in what patterns.
Speaker 3: Right, So, Ruxton and Hansel here ultimately point out that okay,
Speaker 3: we have the ant lion though, and of course the
Speaker 3: worm lion. These are exceptions to the rule. They make
Speaker 3: use of a pitfall trap, and so the authors ask
Speaker 3: why is this basic tactic not more common in the
Speaker 3: animal world? How hard is it, after all to dig
Speaker 3: a hole? They're easy, they're cheap, and yet you don't
Speaker 3: see this technique used by virtually anything outside of some
Speaker 3: ant lions and worm lions. Apparently, the lack of more
Speaker 3: pitfall traps than nature was something of a mystery and
Speaker 3: remain something of a mystery.
Speaker 1: Yeah, that is interesting, Okay, so it took me a
Speaker 1: second to get the distinction they're making. But they're saying
Speaker 1: that the ant lion and the wormline would be kind
Speaker 1: of an outlier because they don't have complex intelligence and
Speaker 1: imagination like humans, so they're not inventing traps with cognitive powers.
Speaker 1: But they also don't secrete a material that CONTs institutes
Speaker 1: the basis of the trap like a spider. They're literally
Speaker 1: just building a trap out of the dead environment around
Speaker 1: of them by digging a conically shaped hole in such
Speaker 1: a pattern that ants get stuck in it when they
Speaker 1: fall down the side. And why is that so rare,
Speaker 1: because it would seem like that that should be a
Speaker 1: strategy that lots of animals could easily employ.
Speaker 3: Right, Yeah, again, holes are ultimately easy to make, low energy.
Speaker 3: Why not? Why why? Why why is this cat not
Speaker 3: making a hole and using that as part of its
Speaker 3: hunting tactics?
Speaker 1: So what are their thoughts on this, like, why would
Speaker 1: why wouldn't we see this more often?
Speaker 3: Well, they proposed two speculative reasons for the lack of
Speaker 3: pitfall traps in nature. The first one is pitfall traps
Speaker 3: may require a specialist micro habitat. In other words, you
Speaker 3: can't do this just anywhere. Conditions have to be just right,
Speaker 3: such as you know, we can look at to the
Speaker 3: ant lions, they have to be kind of sandy conditions.
Speaker 3: You know, you have to have that kind of granular environment.
Speaker 3: So it's the kind of tactic that a potential trap
Speaker 3: builder would not necessarily be able to employ all over
Speaker 3: the place. You would have to depend on again, on
Speaker 3: a specialist micro habitat.
Speaker 1: I think I recall from our Sarlac episode where we
Speaker 1: had a segment about the ant lion that they needed
Speaker 1: the grains of soil to be of a particular size,
Speaker 1: like the sandy grains above or below a certain diameter
Speaker 1: threshold would not work very well for making the traps.
Speaker 3: Yeah, yeah, Now the second point is that with the
Speaker 3: ant lion in particular, the trap target's small prey, and
Speaker 3: since they may be more functionally tied to their trap
Speaker 3: than spiders are, traps of this nature could serve as
Speaker 3: like basically a major bull's eye for potential predators. And
Speaker 3: indeed the main predators of ant lions and worm lions
Speaker 3: are birds who know what to look for.
Speaker 1: That's a really good point. So by building a trap
Speaker 1: and then sitting in it and waiting for your prey
Speaker 1: to fall in, you were also usually going to be
Speaker 1: making a structure that makes it easy for things that
Speaker 1: want to eat you to define where you are. You know,
Speaker 1: they don't have to look too hard because you've made
Speaker 1: a big hole in the ground.
Speaker 3: Right and and spiders just have a little more leeway
Speaker 3: with the situation. Now, I should point out Hansel also
Speaker 3: wrote an entire book which I'm going to reference here
Speaker 3: in a minute. He spends a lot of time in
Speaker 3: that book talking about spiders and how, you know, sometimes
Speaker 3: spider webs are very visible and other times they are not,
Speaker 3: and how that plays into the you know, the ultimate
Speaker 3: kind of complex relationship between spiders and the creatures that
Speaker 3: would eat spiders. But just thinking about this as the
Speaker 3: trap being this conspicuous thing. This we actually see this
Speaker 3: in a lot of our fantastic trap fiction. You know
Speaker 3: that moment when the target of the clever cinematic trap,
Speaker 3: especially if it's laid by the protagonists, the enemy almost
Speaker 3: sets it off, right, like the predator almost triggers the
Speaker 3: trip line you've prepared. But then something happens, right the
Speaker 3: monster deduces that the trap is there, or it suspects
Speaker 3: that something is off.
Speaker 1: Oh, and maybe even the presence of a trap is
Speaker 1: how the hero knows that they have stumbled across the
Speaker 1: bad guy's hideout.
Speaker 3: Yeah. Yeah. It even reminds me a bit of our
Speaker 3: recent weird house selection, The Lift. This was the Killer
Speaker 3: Elevator movie, the Killer Elevator in this or I guess
Speaker 3: you were more specifically the weird biobrain that's been installed
Speaker 3: in the elevator shaft to power these elevators. It's kind
Speaker 3: of an obligate trap predator, but it's so tied to
Speaker 3: that environment that it's a little tricky, like it's not
Speaker 3: able to pull off every kill, and it's eventually destroyed
Speaker 3: by prey that is too clever for it.
Speaker 1: Brilliant analogy. This is true. The killer elevator is an
Speaker 1: obligate trap predator.
Speaker 3: I also have to point out, speaking of the Sarlac,
Speaker 3: is that recent Mandalorian episodes have also sort of played
Speaker 3: with this idea. Yeah, yeah, the Mighty Sarlac. The Startlack's
Speaker 3: pretty impressive, but they make it clear that even these
Speaker 3: great trap predators can be a soom by the mighty
Speaker 3: create dragon that lives in the deserts of Tatooine. So
Speaker 3: knowing you're there being you know, this identifiable organism in
Speaker 3: the sand, that can have a huge downside to it.
Speaker 1: Now, I was trying to think of counterpoints to the
Speaker 1: idea that. Okay, so sitting at the bottom of a
Speaker 1: pitfall trap and waiting for prey to fall into you
Speaker 1: and then eating that that makes you vulnerable to predators
Speaker 1: that want to find you. Well, well, what if you
Speaker 1: just make pitfall traps and then you go away and
Speaker 1: then you know, leave them there and then come back
Speaker 1: like a human hunter might do, you know, leave a
Speaker 1: trap out in the woods and then come and see
Speaker 1: what it collected lobster traps or something. But I can
Speaker 1: see downsides to that as well, because if it's just
Speaker 1: a pit trap, you could imagine that, well, something might
Speaker 1: fall in there, but then something else might eat it
Speaker 1: before you get to it, right, so, or it might
Speaker 1: you know, if you have to make these all over
Speaker 1: the place, you might spend a lot of energy going
Speaker 1: around from one to the other. So is that really
Speaker 1: all that much better than just hunting?
Speaker 3: Well, and then it kind of comes back to this
Speaker 3: idea that the trap laid by an animal especially still
Speaker 3: requires the lethal mechanism, and in the case of the antlime,
Speaker 3: the legal lethal mechanism is itself. It is still essentially
Speaker 3: an ambush predator like again, like Emmilin says, quote a
Speaker 3: quick strike weapon that immediately incapacitates its victim.
Speaker 1: Yeah, I can't believe I didn't think of that. That's,
Speaker 1: of course a good point. You have to find a
Speaker 1: way to kill the prey, right.
Speaker 3: So I mentioned that that Henzel has a whole book
Speaker 3: that deals with with some of this a little bit,
Speaker 3: but just sort of the broader picture of animals building things.
Speaker 3: It's titled Animal Architecture, and I was reading through this
Speaker 3: a bit. He contends that we're not looking at traps
Speaker 3: when we're looking at cases of an animal baiting another animal,
Speaker 3: because traps are a kind of subset of animal architecture,
Speaker 3: an engineered space that aids in capture.
Speaker 1: Okay, so by his metric here, what the burrowing owl
Speaker 1: does by leaving dung out around its nest and having
Speaker 1: this attract insects to it, that would not count as
Speaker 1: a trap because it is not a structure that in
Speaker 1: any way aids and capture. It just attracts prey to
Speaker 1: a site.
Speaker 3: Oh, by the way, I want to also, speaking of
Speaker 3: the burrowing owl again, I want to throw in that
Speaker 3: while some burrowing owls do build their own burrows, they're
Speaker 3: also burrowing owls that acquire the burrows of other creatures. Anyway,
Speaker 3: I want to read this quote from Hansel here. I
Speaker 3: think he puts it rather well concerning the animal architecture
Speaker 3: and traps quote. Whereas a house can just be a
Speaker 3: barrier between the builder and the outside world, a trap
Speaker 3: has a dynamic relationship between itself and the prey. The
Speaker 3: prey needs to approach the trap in a particular orientation
Speaker 3: to it, and then needs to be restrained by it.
Speaker 3: Traps are therefore more complex than homes and need to
Speaker 3: be more precisely engineered, and then he goes on to
Speaker 3: point out the quote among the vertebrates, trap builders were
Speaker 3: apparently absent until the recent history of man. Now he
Speaker 3: cites human mental capacity once more for the construction of
Speaker 3: such traps, noting quote, Virtually all non human trap builders
Speaker 3: use self secreted materials, and the capture principle they adopt
Speaker 3: is the net. Exceptions are simple in design and operation,
Speaker 3: as well as rare, and then he goes on to
Speaker 3: specifically mention antlions, worm lions, and larval diptra.
Speaker 1: But anyway, a large takeaway here is that trap building
Speaker 1: is not as widespread in the animal kingdom as you
Speaker 1: might expect. Humans make a lot of traps. There are
Speaker 1: some very specialized animals, especially some invertebrates, that use traps
Speaker 1: made of materials that they secrete from their own bodies,
Speaker 1: but generally, trap building is not a very widespread hunting
Speaker 1: strategy among animals of planet Earth, in which case it
Speaker 1: would be very interesting to find examples of animals such
Speaker 1: as ants, that make traps in order to get their nutrition.
Speaker 1: And I guess that's a good segue to what I
Speaker 1: to the main focus of today's episode. Which was a
Speaker 1: couple of examples I came across of ants that do
Speaker 1: something that could be interpreted as building traps as a
Speaker 1: hunting strategy.
Speaker 3: Yeah, and I mean it would make sense that we
Speaker 3: might find something like this in the ant world because
Speaker 3: ants are masters of construction, they alter their environment, they're
Speaker 3: capable of practicing agriculture. They as we've discussed in previous
Speaker 3: episodes of the show, they engage in complex conflicts that
Speaker 3: we might well compare to warfare. They can solve problems there.
Speaker 3: I mean, the list goes on and on. Ants are
Speaker 3: amazing as of course, as the now Light e O.
Speaker 3: Wilson was fond of reminding us, you know, ants, there
Speaker 3: are incredible creatures that we've covered them numerous times in
Speaker 3: the show before, we're covering today, and I'm sure we'll
Speaker 3: cover them again exactly.
Speaker 1: So the first example I want to talk about I
Speaker 1: found so interesting, and this one also has some interesting
Speaker 1: differences in interpretations I came across. But just to start
Speaker 1: with the basic report. I was reading about this in
Speaker 1: a paper published in Nature in the year two thousand
Speaker 1: and five by land Jan Pascal, Jean Solano, Julian Irole,
Speaker 1: Bruno Corbara and Jerome Oreville called arboreal ants build traps
Speaker 1: to capture prey, and also as a supplement to the
Speaker 1: paper in Nature, I was reading a summary feature that
Speaker 1: was also in Nature by NoREL Tawi, published in April
Speaker 1: two thousand and five, called Amazonian ants ambush prey. So
Speaker 1: here's the deal. There's a plant in the Amazon called
Speaker 1: Hertella phisofera, or maybe Phisophora physo phora. I'm going to
Speaker 1: try to say fizzof so these here Tella plants. Plants
Speaker 1: in this genus are woody trees or shrubs. I've seen
Speaker 1: them called both trees and shrubs, but they're if you're
Speaker 1: trying to picture them as a tree, you should be
Speaker 1: imagining a small tree, so woody stems, but not like
Speaker 1: you know, sky high. Plants in this genus are found
Speaker 1: in the tropics across multiple continents, but their diversity is
Speaker 1: concentrated around the Amazon, and they typically have flowers that
Speaker 1: are pollinated by butterflies. And this one species in particular,
Speaker 1: here Tella physophera, is what the authors of the paper
Speaker 1: call an ant plant. This is a plant species that
Speaker 1: is known to have a specific biological relationship with a
Speaker 1: species of ant and these can be found throughout the world.
Speaker 1: There are very common mutualisms, or you know, various kinds
Speaker 1: of symbiotic relationships between ant colonies and the trees or
Speaker 1: plants they inhabit. Now, this plant in particular has a
Speaker 1: relationtionship with the arboreal ant alomeras decim articulatus, and they
Speaker 1: live on the body of the plant, forming colony centers
Speaker 1: in what the authors of the paper call leaf pouches.
Speaker 1: They are these little bulb looking things that can usually
Speaker 1: be found at the places where the branches split into leaves.
Speaker 1: They look like these it's kind of hard to describe them.
Speaker 1: They're just these little like green lobes or orbs, and
Speaker 1: apparently the ants like to get inside those and make
Speaker 1: nests in there.
Speaker 3: Now. Already, one of the things that's that I'm reminded
Speaker 3: of is the idea of like a specialist micro habitat.
Speaker 3: And if you have a situation where a plant is
Speaker 3: the home to the ants, that they have this ant
Speaker 3: plant relationship in place, you know that the plant itself
Speaker 3: is kind of the environment, it's kind of the micro
Speaker 3: habitat that the ant is the master off.
Speaker 1: That's exactly right. But the interesting thing is of course,
Speaker 1: ants being builders, some ants will form complex, you know,
Speaker 1: dugout colonies in the ground or other types of interesting
Speaker 1: engineered environments. They can also engineer the microhabitat of the
Speaker 1: surface of a plant, and that's what we're going to
Speaker 1: be talking about in this case. Oh and I should
Speaker 1: say that the colonies that were looked at in this
Speaker 1: two thousand and five paper were from French Guyana in
Speaker 1: northern South America. But so what you find in these
Speaker 1: plants that are occupied by their familiar ant species is
Speaker 1: that along the stems of the host plant, the ants
Speaker 1: will build what the authors of this paper call galleried structures,
Speaker 1: or sometimes they just say galleries. It's kind of hard
Speaker 1: to describe exactly what this is, but imagine a kind
Speaker 1: of platform built out over the surface of the stem
Speaker 1: of the plant, and it's a platform that the ants
Speaker 1: can crawl underneath. And then this platform has a kind
Speaker 1: of spongy texture, almost as if fits or honeycomb texture.
Speaker 1: It's aligned with all these holes in the platform that
Speaker 1: the ants can crawl in and out through. Generally the
Speaker 1: holes are just slightly larger than the diameter of one
Speaker 1: of the worker ants heads. So through these platforms raised
Speaker 1: above the stem of the plant. Ants crawl underneath them,
Speaker 1: but then crawl up and up and down, in and
Speaker 1: out through the holes in the platform.
Speaker 3: Yeah, it is kind of difficult to describe it because
Speaker 3: it is so different from something that that humans would
Speaker 3: for the most part build, you know, by virtue of
Speaker 3: the ants being far more mobile and sort of living
Speaker 3: in a more three dimensional space than human beings tend to.
Speaker 1: By the way, these are great to look up, probably
Speaker 1: unless you suffer from trip to phobia, in which case
Speaker 1: stay far away.
Speaker 3: Yeah, if you're if you're freaked out by things like
Speaker 3: lotus pods and random holes and things, yeah, you might.
Speaker 3: You might want to avoid this particular Google image search.
Speaker 1: Now, how do the ants build these galleries, Well, they
Speaker 1: apparently make them by cutting off tricombs from the stems
Speaker 1: of the plant. Tricombs is a word that comes from
Speaker 1: the Greek word for hares. These are small, little fibery
Speaker 1: appendages that poke out from the surface of a plant.
Speaker 1: You've probably seen lots of plants before that have little
Speaker 1: hairy things all over the stem or the leaves. Those
Speaker 1: are tricombs, and they do look a lot like hares.
Speaker 1: So the worker ants will move along the stem of
Speaker 1: a Hairtella physophera plant, clearing away the tricombs, and then,
Speaker 1: just to read from the language used in the paper here,
Speaker 1: quote then using uncut tricombes as pillars, they build the
Speaker 1: galley's vault by binding cut tricombs together with a compound
Speaker 1: that they regurgitate later. This structure is reinforced by the
Speaker 1: mycelium of a complex of sooty mold species that has
Speaker 1: been manipulated by the ants. Fungal growth starts around the
Speaker 1: holes and then spreads rapidly to the rest of the structure.
Speaker 1: So I think you heard that right. So these ants
Speaker 1: build their galleries along the stem of the plant by
Speaker 1: cutting the hairs off of the plant where they live,
Speaker 1: then using those hairs as building materials, along with their
Speaker 1: own barf as a kind of mortar, and then holding
Speaker 1: everything together by seating it with mold or fungus that
Speaker 1: they farm. So they have a kind of agricultural project
Speaker 1: for farming fungal rebar that they use to reinforce the
Speaker 1: galleries that they build. And in quotes given to the press,
Speaker 1: I've seen the authors of this study compare this composite
Speaker 1: material to fiberglass.
Speaker 3: Wow, Yeah, that does seem like a good comparison. Oh man,
Speaker 3: I mean, it's just so amazing that it's not just
Speaker 3: like this physical act, but they're actually yeah, seating it
Speaker 3: with with this this mold. Oh man, they're kind they're
Speaker 3: build it, but they're also kind of growing it.
Speaker 1: Be amazing, and they tend to it as it grows.
Speaker 1: So I wanted to read another section from the study
Speaker 1: where they talk about the evidence that the ants are
Speaker 1: actively tending the fungus as it reinforces these structures. They say, quote,
Speaker 1: we noted that the stems of thirty four young seedlings,
Speaker 1: which had not yet developed leaf pouches, did not bear fungus.
Speaker 1: Nine saplings raised in a greenhouse in the absence of alomeras.
Speaker 1: That's the ants developed leaf pouches but never bore fungus. However,
Speaker 1: fifteen saplings raised in the presence of ants bore mycelia,
Speaker 1: whose development was limited to the galleries. When we eliminated
Speaker 1: the associated ants from five of the fifteen, the fungus
Speaker 1: on the galleries grew into a disorganized structure, and none
Speaker 1: of the nine new stems that developed bore any fungus
Speaker 1: at all. Okay, so the fungus is only showing up
Speaker 1: on the plant when the ants are there on the plant.
Speaker 1: And if you take the ants away from the plant
Speaker 1: after they've been using the fungus to reinforce their their galleries,
Speaker 1: the fungus kind of grows out of control in what
Speaker 1: they call a disorganized structure. But with the ants still there,
Speaker 1: it stays nice and tightly formed around the holes in
Speaker 1: the galleries. So they're tending their garden. It's like a
Speaker 1: living I don't know, it's like if you had to
Speaker 1: have maintenance workers constantly sort of gardening and tending to
Speaker 1: the fungus that held up your skyscrapers.
Speaker 3: Wow.
Speaker 1: But here's where we start getting to the trapping. So
Speaker 1: the authors of this study say that they noticed that
Speaker 1: sometimes larger insects would become immobilized on the surface of
Speaker 1: the galleries. So you got these these spongy surfaces, ants
Speaker 1: crawling underneath them, and sometimes like a locust or a butterfly,
Speaker 1: some bigger insect lands on the gallery and then it
Speaker 1: gets stuck. What's going on here, Well, they started to
Speaker 1: investigate whether the galleries could be functioning as a type
Speaker 1: of trap. And here's what they say about how the
Speaker 1: ambush works quote. Our observations revealed that Alomiras workers hide
Speaker 1: in the galleries with their heads just under the holes,
Speaker 1: mandibles wide open, seemingly waiting for an insect to land.
Speaker 1: To kill the insect, they grasp its free legs, antennae,
Speaker 1: or wings and move in and out of the holes
Speaker 1: in opposite directions until the prey is progressively stretched against
Speaker 1: the gallery and swarms of workers can sting it. The
Speaker 1: ants then slide the prey over the top of the gallery,
Speaker 1: again moving in and out of the holes, but this
Speaker 1: time in the same direction. They move it slowly towards
Speaker 1: a leaf pouch where they carve it up. Oh and
Speaker 1: then once they get to one of these population centers
Speaker 1: of the colony, you know, the these nest sites in
Speaker 1: the leaf pouches, they tend to feed bits of protein
Speaker 1: from the insect to their young.
Speaker 3: Well, yeah, this is amazing and suitably brutal for the
Speaker 3: world of ants. So this, this larger creature lands or
Speaker 3: walks on to the structure. You know, they're reaching out
Speaker 3: of holes to pull it straight down, and then they
Speaker 3: transfer it to a place where they can carve it up.
Speaker 1: Right. So yeah, there's no sentimentality in the world of ants,
Speaker 1: they're just like, okay, this is edible, It's time to
Speaker 1: get to butcher in But anyway, these observations reveal this
Speaker 1: fascinating three way interaction between the plant, the fungus, and
Speaker 1: the ant all sort of living together in this this
Speaker 1: three way life cycle. Essentially that apparently serves the purpose
Speaker 1: of creating a trap to get larger insects. You know
Speaker 1: these Oh I don't think I mentioned, but the Alamiris
Speaker 1: decim articulatus ants are very small. It's a structure that
Speaker 1: allows these tiny ants apparently to capture kill and butcher
Speaker 1: much much larger prey.
Speaker 3: All right, And of course the plant out of all
Speaker 3: of this gets some slight mutilation from the ants, but
Speaker 3: is protected from larger insects that would otherwise no on
Speaker 3: it and do more harm to it than just creating
Speaker 3: an interesting lattice work out of its body.
Speaker 1: Presumably, I mean, I think often there is such a
Speaker 1: relationship going on. The insect also provides a benefit to
Speaker 1: the plant somehow, though in the sources I was reading
Speaker 1: it wasn't clear to me exactly if it's known what
Speaker 1: the major benefit provided by the ants is, but I
Speaker 1: would guess that's right, that they're probably protecting the plant
Speaker 1: from herbivore large herbivore insects that would chew its leaves
Speaker 1: down or something, But I don't know for sure. I
Speaker 1: gotta admit right.
Speaker 3: And then of course we also have to always realize
Speaker 3: that in the natural world the line between parasitism and
Speaker 3: symbiosis is sometimes a bit thin. These are not relationships
Speaker 3: that are governed by strict contracts, so you might see
Speaker 3: a little bit of push and pull over the course
Speaker 3: of evolutionary history.
Speaker 1: Ants will take whatever they can get.
Speaker 3: You're right, so you be careful about entering into a
Speaker 3: bargain with the ants.
Speaker 1: But on the other side of all this, I wanted
Speaker 1: to come back on it because I found a book
Speaker 1: where the trap interpretation of these structures has been challenged.
Speaker 1: And in fact, this book was by somebody who's come
Speaker 1: up on the on I think episodes we did about
Speaker 1: ants last year, the biologist Mark W. Moffatt. Yes, yes, yeah,
Speaker 1: So he has a book called Adventures among Ants that
Speaker 1: was that came out in twenty ten University of California Press.
Speaker 1: And in this book I found a section where Moffatt
Speaker 1: argues that the trap interpretation of these structures built by
Speaker 1: alameiras decim articulatis is in fact a misinterpretation. Now I'm
Speaker 1: not sure he's right about this, but I do want
Speaker 1: to explain what he claims, so it's a bit of background.
Speaker 1: In the section of the book directly preceding this, Moffatt
Speaker 1: has been talking about his observations of various species of
Speaker 1: army ants on raiding parties to forage for food and
Speaker 1: also on defensive patrols to protect the colony and the
Speaker 1: rating column from threats, and one of his observations in
Speaker 1: this preceding section is how difficult it is sometimes to
Speaker 1: tell the difference between these two behaviors and how easily
Speaker 1: one bleeds into the other. So, according to Demoffitt, for
Speaker 1: most army ants, their defensive attacks on a creature that
Speaker 1: is perceived to be threatening the raiding column can quickly
Speaker 1: turn into a foraging raid in itself. So if the
Speaker 1: threat is killed, it is pretty much immediately chopped up
Speaker 1: into pieces and carried away as food. So it's kind
Speaker 1: of like if you imagine every monster movie ended with
Speaker 1: the heroes butchering and eating the monster after they finally
Speaker 1: defeated it.
Speaker 3: Well, we do see that sometimes. In fact, that occurs
Speaker 3: in the Mandalorian but the case of the Great Dragon.
Speaker 3: But but yeah, we should see more consumption of the
Speaker 3: d of dragons and monsters and so forth. Use every
Speaker 3: part of the monster be responsible.
Speaker 1: Well, I don't know. I mean that's you know, humans
Speaker 1: are different than ants. I mean, ants are not going
Speaker 1: to let anything go to waste. Humans, after you've fought
Speaker 1: a monster, you might just want to have nothing to
Speaker 1: do with it. To each species their own. But anyway,
Speaker 1: so from here, Moffat moves on to describing the ant
Speaker 1: I've been talking about Elimeris decim articulatus, and he's describing
Speaker 1: its living situation. The one distinction he makes I couldn't
Speaker 1: find out what was what was the disconnect here? But
Speaker 1: he said, you remember how I said that the ants
Speaker 1: build these gallery structures out of tricombes cut from the plants,
Speaker 1: a little plant hairs, mixed with their own regurgitation or vomit,
Speaker 1: and then lined with the mycelium of the fungus that
Speaker 1: they cultivate. Mofatt describes it the same way, but he
Speaker 1: mentions feces rather than vomit. And I don't know who's
Speaker 1: right there. But anyway, Moffatt gives a few reasons that
Speaker 1: he had doubts about the generally accepted interpretation of this
Speaker 1: structure as a trap, specifically as a trap, because he
Speaker 1: says a trap implies that, for example, a locust landing
Speaker 1: on the ant gallery would not have landed there if
Speaker 1: it saw the ants. The trap would be performing the
Speaker 1: function of hiding the ants, so you know, they're hidden
Speaker 1: beneath the vault of the gallery, so that the prey
Speaker 1: insect feels it's safe enough to land and then they
Speaker 1: jump out and grab it.
Speaker 3: Okay, this would be in keeping with say the trapdoor
Speaker 3: spider would probably be a great example of this.
Speaker 1: Yeah, yeah, I think that's comparable. That's how it would
Speaker 1: function as a trap. But Moffitt writes that he thinks
Speaker 1: this is unlikely because he doubts that grasshoppers would really
Speaker 1: be able to notice the tiny workers of this ant
Speaker 1: species anyway, quote particularly in mid leap, or that they
Speaker 1: would be able to change course in mid leap after
Speaker 1: noticing them. So he was a little iffy on that, like,
Speaker 1: I'm not sure that the trap would really serve much
Speaker 1: purpose if it's supposed to be hiding the ants from
Speaker 1: the prey animal, because these are insects that are much
Speaker 1: larger than the ants anyway.
Speaker 3: Right, So he's saying, basically saying like this might be
Speaker 3: if this was a trap, which he doesn't think it is,
Speaker 3: it would be a preposterous trap, an unnecessary trap. And
Speaker 3: while again we love unnecessarily complex and preposterous traps in
Speaker 3: our cinema, we're not talking about cinema here. We're talking about.
Speaker 1: Evolution, yeah, and sufficiency.
Speaker 3: Yeah yeah. Things need to be ruthlessly efficient, and if
Speaker 3: it's not ruthlessly efficient, it is going to change or
Speaker 3: go away.
Speaker 1: But anyway, those are his suspicions, so he decided to
Speaker 1: put them to the test. So he tells a story
Speaker 1: of that he was studying colonies of this ant in
Speaker 1: the wild in Ecuador, and he put together a test
Speaker 1: to interrogate the trap interpretation. So to read from the
Speaker 1: section of Moffitt's book where he describes this test, he says, quote,
Speaker 1: hung a mosquito net over a plant with a thriving
Speaker 1: alomeras colony, added one hundred grasshoppers and katie diids, and
Speaker 1: sat inside for the next five mornings. An unusual case
Speaker 1: of using a mosquito net to keep insects in instead
Speaker 1: of out. Even after the grasshoppers settled down, they were
Speaker 1: indiscriminate in their movements, hopping from where the ants hid
Speaker 1: under the structures to where ants strolled in full view,
Speaker 1: to where there were no ants at all. When they
Speaker 1: landed among the ants, even on the structures, they got
Speaker 1: away unhurt. Certainly, if the structures served as traps, they
Speaker 1: were inefficient ones. So he's saying in his observations here,
Speaker 1: he's seeing very little correlation between the structures and the
Speaker 1: hunting behaviors of the ants or the behaviors of the
Speaker 1: prey insects. So what purpose does he believed the galleries
Speaker 1: are serving. Well, he points out that the galleries tend
Speaker 1: to run along the stems of the tree, connecting each
Speaker 1: nest pouch to another nest mouch, and they quote contain
Speaker 1: a highway of workers commuting from nest to nest. And
Speaker 1: then he points out that other insects, including other ant species,
Speaker 1: do sometimes build various types of physical covers over their trails,
Speaker 1: which are generally interpreted to be defensive in nature. For example,
Speaker 1: some marauder and driver ants have been observed to build
Speaker 1: soil covers over their trails, So could that be what's
Speaker 1: going on in this case? Could these galleries that the
Speaker 1: ants build actually be defensive in nature? Another strike here?
Speaker 1: According to Moffat, he observed that the workers at his
Speaker 1: study site did not actually sit and wait at the
Speaker 1: holes in these galleries, as you might expect them to
Speaker 1: do if they were planning an ambush. He says that
Speaker 1: when conditions were normal, so like if the colony is
Speaker 1: not in an agitated state, things are just sort of
Speaker 1: going along normally. Most of the gaps in the gallery
Speaker 1: structures were unoccupied. But he says this chain when there
Speaker 1: appeared to be some kind of threat to the colony. Quote,
Speaker 1: after a day of pulling grasshoppers from my hair, I
Speaker 1: noticed interlopers of another ant, a species of Fidolei or
Speaker 1: big headed ant, climbing the plant to pin down a
Speaker 1: wounded grasshopper missed by the Alomiras. Upon the arrival of
Speaker 1: the fidole ants, the Alomiras workers began to guard each
Speaker 1: of the several dozen entrances to their arcade. And that's
Speaker 1: the arcade, is what he's calling the things that the
Speaker 1: other authors called the galleries the several dozen entrances to
Speaker 1: their arcade nearest the commotion caused by the intruders. These guards,
Speaker 1: aided by nest mates roaming the arcade surface, also caught
Speaker 1: and killed one fidoli and carried it off. So, based
Speaker 1: on these observations, moffittt argues that the galleries are more
Speaker 1: likely defensive to protect trails of workers moving from one
Speaker 1: leaf pouch to the other, but that when something attacks
Speaker 1: or threatens the colony, the workers quickly shift their behavior
Speaker 1: from travel to defense, and then they occupy the holes
Speaker 1: and start biting violently at anything that comes near. And
Speaker 1: of course, if they are able to immobilize an attacker
Speaker 1: or not necessarily an attacker, if they're able to immobilize
Speaker 1: whatever it is that put them on the defense, they
Speaker 1: immediately shift rolls again and turn that threat into food
Speaker 1: and begin butchering it for the colony again, to cook
Speaker 1: the monster, so to speak.
Speaker 3: So we might be better to think of these as
Speaker 3: defensive fortifications, kind of like to use like a medieval
Speaker 3: castle or fortress scenario. It's kind of like the various
Speaker 3: crinolations and murder holes and arrow slits, except with the
Speaker 3: added point that in this case the occupants of the
Speaker 3: castle or fortress would eat those that they killed defending it.
Speaker 1: Right, That's what Moffatt argues, And so to finish up
Speaker 1: his section, he says in the end, quote in this
Speaker 1: way the organization of a super organism, referring to ants.
Speaker 1: There because I think you can make the argument that,
Speaker 1: you know, an ant colony might be best understood as
Speaker 1: one organism rather than many. It is a super organism
Speaker 1: composed of many different bodies, he says it quote can
Speaker 1: be more responsive than the tissues in a body. Trail
Speaker 1: Bound workers can shift seamlessly in their behavior from transport
Speaker 1: to protection to predation. It's as if one's liver could
Speaker 1: change function when the heart is incapacitated and pump blood.
Speaker 1: So obviously I don't know who's right here. Moffatt's book
Speaker 1: is more than ten years old at this point, and
Speaker 1: most of the things I read about this ant species
Speaker 1: alomeris decim articulatas still describe the galleries as ambush traps.
Speaker 1: And I'm not sure which interpretation is correct, but I
Speaker 1: do think either way, Moffatt makes a very interesting point
Speaker 1: about the fluidity of function when it comes to ant behavior.
Speaker 1: How you know one moment's enemy is the next moment's lunch.
Speaker 3: Right, Yeah, Like the ant colony is not just trying
Speaker 3: to do one thing. It has a lot of objectives
Speaker 3: and it has again this fluidity of function. Whereas it's
Speaker 3: far easier to look at a web building spider and
Speaker 3: know what's up. You know that the web is its purpose,
Speaker 3: the web is kind of its sole, and there's no
Speaker 3: question about why it constructed the web.
Speaker 1: I guess. Also, this raises another question about what counts
Speaker 1: as a quote trap because assuming for a second that
Speaker 1: Moffatt's interpretation is correct, I don't know it is, But
Speaker 1: if he's right that these structures are primarily to defend
Speaker 1: the ant trails, but then when something when a threat
Speaker 1: presents itself, they turn around and use the holes in
Speaker 1: the galleries as murder holes and then eat whatever they
Speaker 1: can immobilize, does that count as a trap? Like how
Speaker 1: specialized does a structure have to be for the purpose
Speaker 1: of catching prey in order to be thought of as
Speaker 1: a trap, Because you can imagine other examples where an
Speaker 1: animal builds a structure that's primary defensive in some way,
Speaker 1: it's more like the home from the example you talked
Speaker 1: about at the beginning in that book. You know, it's
Speaker 1: a barrier between you and the outside world. Yet it
Speaker 1: has some kind of feature that like another animal or
Speaker 1: something could get stuck on or some you know, it
Speaker 1: somehow allows you to sometimes opportunistically harvest from the structure
Speaker 1: and then eat from it. And does that count as
Speaker 1: a trap?
Speaker 3: Now? I haven't seen this movie in a very long time,
Speaker 3: but but I think there might be something comparable in
Speaker 3: Home Alone too, am I right? Oh?
Speaker 1: Lost in New York, the one with Tim Curry?
Speaker 3: Oh? What Tim Curry's in that one?
Speaker 1: Oh? Yeah, I think he plays a He plays a
Speaker 1: snooty bell hop or something.
Speaker 3: Okay, that sounds about right.
Speaker 1: Yeah, but yeah, I think the Actually, we were trying
Speaker 1: to figure this out what this was, and Seth's just
Speaker 1: chimed in to let us know he was right. The
Speaker 1: house where he builds the traps and Home Alone two
Speaker 1: is a house that's like under renovation, so it already
Speaker 1: has feature Like, all the traps don't have to be
Speaker 1: in from scratch. There are already features of the house.
Speaker 1: I don't remember exactly what they are, but there are
Speaker 1: things that are dangerous about it already.
Speaker 3: Okay, yeah, yeah.
Speaker 1: But I wanted to talk about my second example of
Speaker 1: ants potentially doing something that you could interpret as a
Speaker 1: trap ok, and this one also involves using foreign materials
Speaker 1: around the nest. So the second example was described in
Speaker 1: a paper that I was reading published in twenty nineteen
Speaker 1: in the journal Ecological Entomology by Innacio Gomez Diego, Santiago
Speaker 1: Ricardo Campos, and Heraldo Vasconcelos. It was called why do
Speaker 1: fight oly oxyops ants place feathers around their nests? And
Speaker 1: I also got some additional information from reading an article
Speaker 1: about the study published in Scientific American by Joshua rapp
Speaker 1: Learn in November twenty nineteen. But here's the deal. So
Speaker 1: there is this species of ant called Fidolei oxyops. We
Speaker 1: were already talking about some fidoli ants in the last
Speaker 1: example because the remember the fidoli ants invaded the tree
Speaker 1: and then they got kind of butchered by the alomiras ants.
Speaker 1: But fidoli ants are a genus known as the big
Speaker 1: head ants, and this species, in particular, fidoli Oxyops, is
Speaker 1: native to South American savannahs. So these would be you know,
Speaker 1: grasslands ants. Sometimes they appear to do something pretty weird.
Speaker 1: They collect feathers and place them around the entrance of
Speaker 1: their nests. So, if you imagine the nest is buried,
Speaker 1: the entrance is basically a hole in the ground, and
Speaker 1: then you might just find feathers all around the holes,
Speaker 1: scattered around on the ground outside the hole. That's weird.
Speaker 1: It might make it look like the ants ate a
Speaker 1: live chicken or something, but that is not what happened.
Speaker 1: They appear to collect the feathers and put them there.
Speaker 3: Yeah, it kind of looks like there's a hole in
Speaker 3: the ground and like a bird was sucked down that hole,
Speaker 3: and this is these are the cartoonish remnants of that incident.
Speaker 1: I thought the same thing. Yeah, I was like, hmmm,
Speaker 1: pop and then just puff of feathers they settle around it.
Speaker 1: But no, that is not what has happened. The ants
Speaker 1: put the feathers there. Strange. So this paper published in
Speaker 1: twenty nineteen in Ecological Entomology, it claims that these feathers
Speaker 1: function as bait to attract prey animals, which then tumble
Speaker 1: into the nest entrance as if it were a pit trap.
Speaker 1: And the Scientific American article actually reports a bit of
Speaker 1: the background on the paper. It says that the studies.
Speaker 1: First author in Nacio Gomez, is an ecologist at the
Speaker 1: Federal University of Visosa in Brazil, and while walking around
Speaker 1: city parks and his college campus, he noticed examples of
Speaker 1: these ant nest entrances with feathers all around him. Apparently
Speaker 1: this had been observed, and also I was looking at
Speaker 1: another paper about this ant species, fidally oxyops. This one
Speaker 1: was by Diego asis at All from twenty twenty one,
Speaker 1: and this paper said that in addition to feathers, there
Speaker 1: will sometimes be other objects around these entrances, including shells,
Speaker 1: flower pedals, and seeds. But this study in particular was
Speaker 1: focusing on the feathers, and so he noticed these feathers
Speaker 1: around the entrances and he wondered what was the deal
Speaker 1: with this. Apparently this had been observed before, and there
Speaker 1: were already a couple of untested hypotheses in the scientific
Speaker 1: literature about what the feathers were doing there. One idea
Speaker 1: was that the feathers could collect do in arid regions,
Speaker 1: so they would help provide the ants with water in
Speaker 1: the mornings, and the other idea was that some of
Speaker 1: the feathers could serve as lures, attracting prey to the nest,
Speaker 1: and so the twenty nineteen study tested both. In one experiment,
Speaker 1: the researchers supplied the ant colonies with water soaked cotton balls,
Speaker 1: so made sure they had access to plenty of water,
Speaker 1: but the ants in these cases preferred to collect feathers anyway.
Speaker 1: It did not seem like access to water played any
Speaker 1: role in their desire to collect feathers, and this could
Speaker 1: be evidence that the feathers were not primarily for collecting water.
Speaker 1: But another test was designed to see if feathers scattered
Speaker 1: on the ground would attract prey. So they tested this
Speaker 1: with artificial traps that were made to resemble the nest
Speaker 1: entrances of these ants, and the team found that if
Speaker 1: you put out a trap and scatter feathers around it,
Speaker 1: for some reason, it will tend to trap more just
Speaker 1: sort of wanderers, you know, arthropods that are out on
Speaker 1: the ground, than traps without feathers, And so interesting question
Speaker 1: why would they do that. Why would a hole in
Speaker 1: the ground surrounded by feathers get more bugs to fall
Speaker 1: into it. It's not known, but Gomez suggests that maybe
Speaker 1: it's something about the smell of the feathers, something about
Speaker 1: the visual appearance. Maybe a quote he gives to the
Speaker 1: Scientific American article, he says, just in general, soil insects
Speaker 1: are quote very curious, So maybe putting an unusual item
Speaker 1: around the entrance to the nest will just tend to
Speaker 1: get wandering bugs to walk up to it and see
Speaker 1: if it's something of use to them. But I think
Speaker 1: this would not count just as baiting the way the
Speaker 1: burrowing owl example would with the cow dung or the
Speaker 1: bison dung, because in this case it's not just to
Speaker 1: get the insects close to the nest. In this case,
Speaker 1: the actual nest entrances, basically holes in the ground, function
Speaker 1: quite well as pit traps because once the prey insect
Speaker 1: falls in, they have difficulty climbing back out, and the
Speaker 1: ants will rather quickly grab and butcher them. Now, this
Speaker 1: is clearly not the only way this ant species has
Speaker 1: to acquire prey. Fidolioxyops do lead the nest to acquire prey.
Speaker 1: They forage like other ant species. But it's possible that
Speaker 1: using the nest as a pit trap and surrounding it
Speaker 1: with feathers as some kind of evolved behavior for luring
Speaker 1: more insects into the hole that helps the colony supplement
Speaker 1: their diet during especially times of the year, such as
Speaker 1: the dry season in this region when prey is more scarce,
Speaker 1: harder to come by.
Speaker 3: So they wouldn't be obligate trap builders. They would they
Speaker 3: would be sort of they would have like a trap
Speaker 3: business on the side. I guess you would say.
Speaker 1: Yes, if the trap interpretation is correct, it seems like
Speaker 1: this would be a supplemental role in getting extra food
Speaker 1: to them, extra diet diversity, especially in times when they're
Speaker 1: they're going to be getting less in their foraging or
Speaker 1: maybe when they're doing less foraging.
Speaker 3: Okay, yeah, because they're you know, again they're altering their
Speaker 3: immediate environment anyway. There and then again, a whole like
Speaker 3: this is not a huge energy investment.
Speaker 1: Is already part of the nest.
Speaker 3: Yeah, already part of the nest. I guess the question
Speaker 3: is coming back to those those reasons that were put
Speaker 3: forth earlier that we don't see more pit traps. Does
Speaker 3: this would this make the the ant population more visible
Speaker 3: to potential predators?
Speaker 1: Yeah?
Speaker 3: I mean maybe so, maybe not. Maybe maybe the animals
Speaker 3: that would be interested in eating the ants already would
Speaker 3: be able to detect their presence. And then again also
Speaker 3: the ants have more capabilities than that one little larva
Speaker 3: at the bottom of a small pit. You know, we're
Speaker 3: not dealing with one organism. We're dealing with this, uh,
Speaker 3: this entire colony of organisms that that kind of behave
Speaker 3: as a single organism.
Speaker 1: Yeah, obviously I don't know what all the you know,
Speaker 1: the cost benefit analysis of this evolutionary calculus would be.
Speaker 1: But but yeah, there must be some reason why by
Speaker 1: having your ant nest a as a pit trap and
Speaker 1: this environment for this ant is is not such a
Speaker 1: it's not such a danger that it outweighs the benefit
Speaker 1: of getting some bugs to fall in as free meals.
Speaker 1: But I also like this because it's like by house analogy.
Speaker 1: It's like if your entire house was just like below
Speaker 1: the ground and the entrance to the house was a
Speaker 1: spike pit trap like a tiger trap. Yeah, just waited
Speaker 1: for things to fall in and be like, oh bonus,
Speaker 1: here's dinner, and you always and you had the lures,
Speaker 1: you had the feathers all around. I don't know what
Speaker 1: that would be in the human example, you put just
Speaker 1: cotton candy around the around the trap that you come
Speaker 1: in through.
Speaker 3: Well, this is certainly another fascinating example. Yeah, and I
Speaker 3: love how both present the possibility of ants building traps.
Speaker 3: But since they are ants, like it's it's not that
Speaker 3: cut and dry, like, ants have a complexity all their own,
Speaker 3: so you can't really look at them in the same
Speaker 3: way that you would look at a single solitary spider
Speaker 3: or certainly even you know, the human example, Like what
Speaker 3: we do with traps and how we think about traps
Speaker 3: is a rather different scenario compared to anything, you know,
Speaker 3: anything that we're seeing in several of these animal examples.
Speaker 1: Yeah, well, I guess that does it for ant traps
Speaker 1: on my end.
Speaker 3: But yeah, well this was fun. Who knows what the
Speaker 3: future will hold. Perhaps there'll be more exciting studies coming
Speaker 3: out of the world of ant research. I mean, it's
Speaker 3: it's highly possible. I mean, we're still we're still making
Speaker 3: significant discoveries about ant species and what they're up to.
Speaker 1: There are frontiers of ants you couldn't even dream of.
Speaker 3: There are ant traps that we don't even know about
Speaker 3: yet because they haven't been sprung on us.
Speaker 1: When you fall into them. You go through the two
Speaker 1: thousand and one stargate and in the room with the
Speaker 1: French furniture.
Speaker 3: You know, we've never watched an ant movie for a
Speaker 3: weird house cinema. I wonder if we should at some point.
Speaker 1: Oh, I have for years been looking at the cover
Speaker 1: of a Blu ray at Videodrome called Phase four. It's
Speaker 1: a picture of a hand with some ants. I know
Speaker 1: it involves ants. I don't know anything else.
Speaker 3: I guess the question I would have, especially after talking
Speaker 3: about ants like this again, is are we looking at
Speaker 3: thinking about movies that have a giant ant in them
Speaker 3: and have encounters with various giant ants, or is it
Speaker 3: truly about the ants as this kind of super organism
Speaker 3: And I like the latter.
Speaker 1: Yeah.
Speaker 3: Yeah, though, maybe having a giant sized ant is kind
Speaker 3: of a way through our fantastic fiction that we think
Speaker 3: about super organisms. So it's kind of like, yes, the
Speaker 3: ants are small, but they work together and they're able
Speaker 3: to do great things. So we just think of like
Speaker 3: a giant ant. That's like just one way of contemplating
Speaker 3: what they're capable of. So the next time ant movies
Speaker 3: come back, if you're out there thinking about resurrecting the
Speaker 3: giant ant movie, consider having them like tear people apart.
Speaker 3: Things like that. You know, crawling out of windows, pulling
Speaker 3: people taunt against the sides of a building and then
Speaker 3: transferring them up to the rooftop and tearing them to pieces.
Speaker 1: Nice final processing.
Speaker 3: Yes, all right, well we're gonna gohe and close out
Speaker 3: this episode here, but we'd love to hear from everybody
Speaker 3: out there about traps, traps and movies, Traps in the
Speaker 3: human world, traps in the animal world. Is there is
Speaker 3: there some corner of this topic you'd like for us
Speaker 3: to explore more in the future. Let us know we
Speaker 3: would love to hear from you. If you would like
Speaker 3: to listen to other episodes of Stuff to Blow Your Mind,
Speaker 3: you will find them in the Stuff to Blow Your
Speaker 3: Mind podcast feed Core episodes on Tuesdays and Thursdays, listener
Speaker 3: mail on Monday's short form artifact on Wednesdays. On Friday,
Speaker 3: we do Weird House Cinema. That's our time to set
Speaker 3: aside most serious concerns and just look at a strange film.
Speaker 3: As always, you can also get to us rather quickly
Speaker 3: by going to Stuff to Blow your Mind dot com.
Speaker 1: Huge Things, So as always to our excellent audio producer
Speaker 1: Seth Nicholas Johnson. If you would like to get in
Speaker 1: touch with us with back on this episode or any other,
Speaker 1: to suggest a topic for the future, just to say hello.
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