OK, I wrote my theory, and then read the article: same.
But I will add that a commercial grower of venus flytraps once got curious, and took a few thousand cloned plantings, growing them in a variety of conditions. As soon as the soil became nourishing, the plants would die. Post mortem seemed to indicate their roots were fungally attacked.
So: plant adapts to living in a food desert (not an actual one, of course; it has to be wet for the carnivory to work, as the article points out). Plant gains weirdo digestion abilities, but at the same time, it no longer needs expensive anti-fungal defences - because the ground isn't rich enough to support parasitic fungi.
Then: human adds the nutrients back in. Boom! The ordinary fungus in the air, which has a tough time invading grass or tree or tobacco or pepper roots (because they have extensive defences, like capsaicin), lands in the rich soil of pretty-much helpless flytrap roots, and has a buffet.
Sorta similar with a lot of plants I imagine, we planted a Madrone tree and it's very tempting to want to water a small & new tree but they can also get root issues if the ground is too wet or doesn't drain well enough. They're highly adapted to living on the sides of cliffs.
We recently had this discussion about house plants as well. The unexpected part is: Too much watering hurts more than too little watering. Especially with bad drainage.
If the watering is on the too-little side for the evaporation and plant size going on, well, the plant will look a little sad for a bit. Then you water it, and it goes back up and looks happy again. This is a situation plants regularly deal with in the wild - drought - and they have adapted to it.
If you water too much, especially with bad drainage, there will be stagnant water in the pot, roots rot and the plant dies with little recourse.
So now I make sure my pots can drain, take my plants outside once or twice a week, absolutely drown their soil and let that drain for an hour or two. This way, the soil becomes saturated without stagnant water and... some of these plants are reproducing and growing at unreasonable rates for the amount of effort placed into them.
I've been trying to grow a mango from a seed for so long. The roots always get hit by black fungus and it dies off. Tallest I got one to grow was about 10"
yes, b. subtilis produces exogenous anti-fungal peptides and VOCs. Additionally, sterilizing the seed before inoculation using sodium hypochlorite or h2o2 would help.
Labor of love (beautiful trees), but they are very iffy trees to get going. I did attempt to help things along by putting lots of madrone duff with it, so as to try to get the right biota.
98% of grass or tree or tobacco or pepper roots are invaded by fungus, and cannot survive in soil if they are not invaded by fungus. Rice is one of the rare exceptions. Having their roots invaded by fungus is probably what enabled plants to colonize land in the first place.
I think that's a double whammy, not only are the fungi ready and willing to use those extra nutrients in the soil, the carnivorous plants have in many cases lost most of their unneeded-in-poor-soils ability to absorb the nutrients. That's why you can feed your flytrap tiny bits of hamburger (or maybe tofu, not sure if the amino balance matters unless that's all they're getting?)
In a clean room maybe, but honestly hydroponics usually makes things like that worse, not better and I say that as someone who's had a set up for over ~5 years at this point.
At the end of the day it's a pit of water with nutrient that is usually somewhat warm. You can control algae with hydrogen peroxide but there is always some water that will stagnate somewhere and lead to some mold level. It's really best to grow plants with a clear growth => harvest cycle so that you can periodically re-sanitize everything.
I've visited Lady Musgrave Island in the Great Barrier Reef. It is covered with trees called "the grand devil's-claws", the seeds of which are barbed and sticky. The seeds stick to the wings of birds eating seeds, and so they can spread across islands.
However, a visitor to the island will soon notice lots of dead birds on the ground. There are no predators or scavengers, so the birds lay there decomposing.
Thus, the trees use the birds not only for reproduction, but also for food. It's a carnivorous forest out there on the reef.
[0] lists 28 documented cases - if we ignore the 5 before 1943 (probably not reliable records), that gives 23 in just over 80 years or roughly one every 3.5 years (although you'd expect that to have increased over time as more people live or tourist near the trees)
Of those 23, 5 were infants (<3y), 1 was killed by 4 coconuts, 1 was killed by a bunch of 57 coconuts(!), and 2 were accidentally killed by their harvesting monkeys.
I was in south India for about a month and I heard of 1 person dying from a coconut during that time period and heard it wasn’t unheard of. Not a lot of people die but plenty of folks get injured.
As the article points out: If conditions exist for "high-quality plant growth" (correct light, soil, moisture, etc) then plants don't make weird adaptations like eating things/water-conservation methods.
However, if those conditions DON'T exist, then it's hard for plants to get very big.
There's also this: the larger a moving creature you're trying to capture, the more resources you need to invest in the trap. Bladderwort exists everywhere because it's easy to trap small/microscopic things. Giant bear-eating plants exist nowhere because consistently trapping a bear with just leaves, sap, and stems is really fucking hard.
At a certain point, the plants reach an equilibrium where the effort is worth the end result, but diminishing returns if they got larger.
One can imagine some pretty twisted stuff, but anyway large mammals tend to have enough brains to learn to recognize dangers without, or failing that, with evolution (think innate fear of snakes).
If you want to speculate about that, then how about the bamboo die-off cycle? Imagine if you lived in the PNW or Appalachia, and every 120 years the entire side of a mountain launched an army of hungry rats at you. Starves all those cute smug “panda” gluttons too.
Reminds me of a semi-plausible mechanism for carnivorous flora from this [0] Worldbuilding Stack Exchange answer by ckersch:
> Bonegrass is a white fungus which grows in wheat fields. Most of the time, the bonegrass fields are normal wheat fields, indistinguishable from other wheat fields except for their exceptionally high yields and relatively low numbers of animal inhabitants. Of course, this entices lots of animals, large and small, to move into the area. Populations boom, fueled by the seemingly unnatural abundance of the wheat.
> And then the bonegrass blooms. Overnight, huge mycelial mats below the wheat fields become active, with white fungal growths growing up the stalks of the wheat plants, using their stalks for support. Then, simultaneously across hundreds of square miles, the bonegrass releases its paralytic spores. Within 12 hours, the wheat fields become pale, white places of death. The fungus then begins to grow over the paralyzed creatures, flooding their body with neurotoxins that keep them immobilized until they die from dehydration over the next few days.
> The dead animals quickly break down, broken apart by the fungus. As suddenly as the bonegrass grew, it will then die back, shrinking back beneath the earth, where it will slumber as the land above it slowly repopulates, drawn by the seeming gaia above the soil, and unaware of the horrors slumbering beneath...
Scary stuff. Symbiotic plant-fungi or plant-bacteria relationships seem like plausible mechanisms for "carnivorous" plants, even if it's not "plants directly eating people" a la Little Shop of Horrors. There are more good answers with a similar premise under the same SE question.
I bought a tiny Venus Fly Trap once, left it in the kitchen, and went away for a weekend.
When I came back the kitchen was buzzing with flies, and the plant had literally gorged itself to death.
This was extra impressive because none of the windows were open. It had somehow leaked attractant scent through gaps I didn't know existed and the flies - not exactly numerous where I was - must have been aware of it from hundreds of yards away.
Point being the plants may be small, but they can be very good at what they do.
I wouldn't think it gorged to death because the leaves close around the fly while digesting. I have a few small Venus fly traps as well and the greenhouse I bought them from said they are really easy to kill with too much or too little water, even just using basic fertilizer. Just speculating of course. These plants are cool but feel so alien.
But yeah they definitely can attract a lot more flies than they can eat and can make the fly problem way worse
As soon as a carnivorous plant gets big enough to be eating young mammals, it hits the Mama Bear barrier. With motivation, even a tiny mammal can do an enormous amount of damage to a plant.
I would have thought that plants which ate neighboring plants, for their easily accessed nutrients and to protect their own access to sunlight, water and forest nutrients, would be pervasive.
I have heard of chemical/strangling/parasitical type competition. The banyan tree is territorial, for instance.
But we would need another name, other than territorial, carnivorous or vegetarian, to describe plant predators which overtly, actively fed on the physical structure or leaves of fellow plants.
There are many parasitic plants, like the well-known mistletoe, which eat other plants. Unlike mistletoe, some of the other parasitic plants have given up completely on phototrophy, depending only on the nutrients sucked from the host plant.
It is likely that there are much more parasitic plants than carnivorous plants.
Plants that feed on other plants must do it similarly to a fungus, by penetrating them and growing into them a root-like organ, for sucking their fluids.
A plant could not bite and chew another plant, because, like the fungal cells, the plant cells have abandoned their ancestral animal-like mobility, by covering their cells with walls made of cellulose, which prevent cell mobility. While there are a few plants capable of infrequent fast movements, like the Venus flytrap, they use special tricks for creating tension in an elastic structure, like when drawing a bow, which would not be suitable for sustaining a sequence of movements.
> A plant could not bite and chew another plant, because, like the fungal cells, the plant cells have abandoned their ancestral animal-like mobility
I would think capabilities like that would be recoverable, if the biological economics worked.
But your point that parasitical plants continuously live off other plants, i.e. they essentially farm them, resolves that. Given victim plants can't run away, their metabolisms are worth far more than any one-time resource extraction.
Nah. Eating and reproducing lots, fast, is a viable means. See: much of the fungi kingdom.
I suppose you could view the passive offspring dispersal system (wind, current, animal digestive tract, raindrops, etc.) as a form of intergenerational movement.
Larger animals tend to more intelligent - presumably there’s a natural limit to the size of prey a carnivorous plant can reliably catch from a static location.
Larger animals are highly undesirable prey because they tend to be able to free themselves from a carnivorous plant (low value), with a high probability of severe damage to the plant in the attempt (high cost): they can just walk or climb away, but also involuntarily break a stalk with their weight, tear open a sac with talons, rip away slowly regenerated adhesive parts, eat something that should be dangerous, and so on.
OK, let's see. You're a plant, so you have photosynthesis. It allows you to tap around 5W (averaged out) per square meter of foliage by just AFK-ing. Your major need: water, you have to evaporate it for the photosynthesis to work. But it's not a problem in your habitat, there's plenty of water available.
You also need nitrogen, phosphorus, and other nutrients, but comparatively little of them. Nitrogen is the toughest one. This is the one that you can easily get from animals, though. So you can evolve a complicated mechanism to trap small animals and digest them for nutrients. It also provides you with a bit of energy, but it's completely immaterial compared to photosynthesis, so you don't even bother evolving all the complicated protein-to-glucose pathways.
Now, you want to grow bigger. How would you do it? Energy is not an issue, the photosynthesis provides plenty of it. But you need to trap more or bigger animals, and that's an issue. There just aren't that many of them, and you can't just get away with simple traps anymore.
Is nitrogen really the bounty, not phosphor? I imagine nitrogen fixation is basically the same problem everywhere, equally distributed through air, but phosphor depends on geological processes, depends on the mineral make of the soil. If phosphor gets depleted, you have two options: Wait for mountains to grow and shed some, or indulge in someone else’s DNA and ATP. Maybe the acidic soil makes uptake harder, or aids wind and water erosion?
Looking at my spotted windowsill, if I was a plant on an evolutionary adventure, I‘d befriend some spiders and turn my crown into a cotton candy guano cloud. I‘d rather have the animal predators do the work and then have them shit in my yard for the nitrogen and phosphor. You only need twigs and then some bioluminescence or stink to help those spiders fill their nets.
Have a fungus rot my legacy core wood so an owl can defecate a hectare of mice and squirrels right into my tummy. Or you look all mighty and judgmental so these funny naked apes drench your soil in the blood of goats and their youths. Is that still a thing?! What about instagramable forest cemeteries? Heard about the tree toilet TikTok challenge? So fun! Super healthy and natural too.
Now thinking of it, I wonder how many plants encourage animals shitting and dying in their yards. Maybe it’s not deterrent, but enterotoxic payment options?
I guess, unless your objective is to grow impractically large fruits, because your human creator couldn’t keep it in their pants, for most plants in most places, neither phosphor nor nitrogen side hustles are really worth the effort.
Yep, nitrogen is the limiting nutrient in swamps. It can be fixated only through biological means, while phosphorus is produced by weathering rocks. Nitrogen fixation is suppressed in swamps, while phosphorus is typically still available from the inflowing streams.
I don't think this is very correct, but why do these biological means fail in bogs/swamps? Kinda my point: Other plants and ecosystems figured out the nitrogen problem all over the world. It's more or less the same everywhere, since nitrogen naturally comes from the atmosphere. AFAIK, there are more or less three ways to have nitrogen input into an ecosystem: Lightning, biological fixation in plants/microbes and artificial synthesis/fertilization.
I suspect the swamp ecosystem has something going which makes nitrogen fixation difficult. All other plants in the swamp need nitrogen to grow, too, how are they doing? Maybe it is the (often) low pH, maybe it's a lack of trace metals for certain enzymes. Maybe the anaerobic conditions favor inaccessible conversion of nitrogen in decay.
Nitrogen can't be completely exhausted, because you have (low) constant influx from the atmosphere everywhere on Earth's surface, even without biological fixation. Phosphorus, on the other hand, can be effectively depleted. The "cycling" of phosphorus happens on geological timescales. A low soil pH may leech out the phosphorus from minerals and have it carried away by wind and water.
I still don't think plants would go the carnivorous route just for the nitrogen. If anything, I suspect they recycle the "nitrogen" as amino acids to save on synthesis. Some carnivorous plants apparently secrete phosphatase into their prey. That's a lot of evolutionary effort...
Carnivorous plants certainly don't mind extra phosphorus, but it's usually not limiting.
> I don't think this is very correct, but why do these biological means fail in bogs/swamps?
They don't. Moreover, the anoxic environment of swamps actually promotes the nitrogenase activity. However, the constant presence of water also diffuses the nutrients, and denitrifying bacteria use ammonia as an energy source. In oxygenated environments, they are typically outcompeted by regular air-breathing bacteria.
This happens in regular soil, but it's normally not saturated with water, so nutrients are not constantly washed out.
> All other plants in the swamp need nitrogen to grow, too, how are they doing?
Not very well. Swamps are not very productive biologically. There is _some_ nitrogen available, it's just that its equilibrium concentration is much lower.
They don’t fit into the pews. Humans design them to be inaccessible to bears. It’s discriminatory. The cats stay away because they get bored easily by people talking about themselves or other people instead of about cats.
> then have them shit in my yard for the nitrogen and phosphor.
Nepenthes Lowii says hi.
"However, pitchers produced by mature N. lowii plants lack the features associated with carnivory and are instead visited by tree shrews, which defaecate into them after feeding on exudates that accumulate on the pitcher lid."
Still, I kinda want to see a tree's light faintly glowing through their guano cloud of horrors. You could plant them next to lakes and such to get rid of mosquitos! But mostly for the eerie atmosphere, to make man afraid of the night again. Whispers of ten thousand feet, be wary of the lantern trees!
I.e., because they got their nutrients from animals they didn't need chloroplasts and the chloroplasts 'broke' over time. Chances are minimal to zero that carnivorous plants will regain chloroplasts. In a way, carnivory in plants is an evolutionary 'dead end' similar to parasitism, which is also often linked to chloroplast loss. Where could the plants evolve 'to' if they have no chance of getting energy from alternative (chloroplast) sources?
>Most of this carnivorous botany is small, but the diversity of different trapping mechanisms raises an evolutionary question.
Isn't the obvious conclusion that:
1. There are many peaks in the fitness hypersurface for plants that correspond to meat eating
2. The peaks have smooth gradients at the outskirts
3. All peaks are minor local maxima
1 is because low nitrogen alone is not enough to make carnivory a net positive contributor to fitness. You need additional factors to make the gradient positive to begin with. That means the peaks (niches) are random and narrow.
3 is because carnivory implies an arms race against prey defenses, competing scavengers, and competing predators. Specialist animals are at a large advantage against plants, especially if meat is still a side dish to sunlight.
To me the interesting question is 2 - most plants don't digest animals at all, so how does this begin to evolve?
I mean, that's a weak evolutionary argument against all forms of predation/prey. It assumes a level of cultural/shared knowledge that doesn't typically exist. Also, size =\= intelligence/problem solving. Chimps and humans are both smarter than gorillas.
Yes, troop 1 of monkeys have learned about the monkey-eating plants that have evolved overnight, but troops 2-10 haven't. Eventually troop 1 leaves the deadly forest, and troop 2 comes in. After a few seasons, they notice these fucking plants keep eating their babies (again, most predators go after babies for the reason you mentioned, they haven't learned how to avoid death yet) and then they move on. Repeat for several centuries. Behold nature in all its splendor.
I like the article's ideas: If you can grow large enough to eat a person, you're getting enough nutrition that you don't need to eat a person.
I used to think carnivorous plants would someday grow huge and eat people like in the movies. Turns out they have always stayed small and just got really clever instead.
This piece made me see it differently. Not growing big is not a flaw. In a place with barely any nutrients, surviving with just a bit of strategy is actually kind of amazing.
OK, I wrote my theory, and then read the article: same.
But I will add that a commercial grower of venus flytraps once got curious, and took a few thousand cloned plantings, growing them in a variety of conditions. As soon as the soil became nourishing, the plants would die. Post mortem seemed to indicate their roots were fungally attacked.
So: plant adapts to living in a food desert (not an actual one, of course; it has to be wet for the carnivory to work, as the article points out). Plant gains weirdo digestion abilities, but at the same time, it no longer needs expensive anti-fungal defences - because the ground isn't rich enough to support parasitic fungi.
Then: human adds the nutrients back in. Boom! The ordinary fungus in the air, which has a tough time invading grass or tree or tobacco or pepper roots (because they have extensive defences, like capsaicin), lands in the rich soil of pretty-much helpless flytrap roots, and has a buffet.
Sorta similar with a lot of plants I imagine, we planted a Madrone tree and it's very tempting to want to water a small & new tree but they can also get root issues if the ground is too wet or doesn't drain well enough. They're highly adapted to living on the sides of cliffs.
We recently had this discussion about house plants as well. The unexpected part is: Too much watering hurts more than too little watering. Especially with bad drainage.
If the watering is on the too-little side for the evaporation and plant size going on, well, the plant will look a little sad for a bit. Then you water it, and it goes back up and looks happy again. This is a situation plants regularly deal with in the wild - drought - and they have adapted to it.
If you water too much, especially with bad drainage, there will be stagnant water in the pot, roots rot and the plant dies with little recourse.
So now I make sure my pots can drain, take my plants outside once or twice a week, absolutely drown their soil and let that drain for an hour or two. This way, the soil becomes saturated without stagnant water and... some of these plants are reproducing and growing at unreasonable rates for the amount of effort placed into them.
I've been trying to grow a mango from a seed for so long. The roots always get hit by black fungus and it dies off. Tallest I got one to grow was about 10"
Try adding some natto innoculant to the seed
For the Bacillus subtilis?
yes, b. subtilis produces exogenous anti-fungal peptides and VOCs. Additionally, sterilizing the seed before inoculation using sodium hypochlorite or h2o2 would help.
Same with Lychee, after a bit the leaves all start getting brown from the tip and die off.
Avocado on the other hand grows like a charm.
Weird. We just planted a madrone too.
Labor of love (beautiful trees), but they are very iffy trees to get going. I did attempt to help things along by putting lots of madrone duff with it, so as to try to get the right biota.
I hope there's a mad scientist somewhere, making a cross-genetic venus flytrap that also produces capsaicin and nicotine.
And is also selecting for size. If other plants are anything to go by we can probably increase the size three fold.
Wait, I've seen this movie. I'd suggest not trying this if your name is Seymour
throw thc in and that will make one hell of a hot tamale
Genius!
So it draws people in with the promise of a nicotine fix, and then sprays them with mace to stop them from struggling free...
98% of grass or tree or tobacco or pepper roots are invaded by fungus, and cannot survive in soil if they are not invaded by fungus. Rice is one of the rare exceptions. Having their roots invaded by fungus is probably what enabled plants to colonize land in the first place.
https://en.wikipedia.org/wiki/Mycorrhiza
I think that's a double whammy, not only are the fungi ready and willing to use those extra nutrients in the soil, the carnivorous plants have in many cases lost most of their unneeded-in-poor-soils ability to absorb the nutrients. That's why you can feed your flytrap tiny bits of hamburger (or maybe tofu, not sure if the amino balance matters unless that's all they're getting?)
Hm. What about hydroponics? Lower risk of fungal infections there.
In a clean room maybe, but honestly hydroponics usually makes things like that worse, not better and I say that as someone who's had a set up for over ~5 years at this point.
At the end of the day it's a pit of water with nutrient that is usually somewhat warm. You can control algae with hydrogen peroxide but there is always some water that will stagnate somewhere and lead to some mold level. It's really best to grow plants with a clear growth => harvest cycle so that you can periodically re-sanitize everything.
You are assuming that they haven't.
Brambles can trap sheep, benefiting from the sheep as fertilizer: https://www.youtube.com/watch?v=mrGobnZq83g
Falling coconuts can not only kill people, but probably kill far more small animals, again benefiting from them as fertilizer,
Came to HN for tech news, left with a disturbing realization that coconut trees might be low-key carnivorous.
If it's a fun kind of disturbing, and you like SciFi, you might enjoy Semiosis.
Right?!
[dead]
I've visited Lady Musgrave Island in the Great Barrier Reef. It is covered with trees called "the grand devil's-claws", the seeds of which are barbed and sticky. The seeds stick to the wings of birds eating seeds, and so they can spread across islands.
However, a visitor to the island will soon notice lots of dead birds on the ground. There are no predators or scavengers, so the birds lay there decomposing.
Thus, the trees use the birds not only for reproduction, but also for food. It's a carnivorous forest out there on the reef.
Going down that line of thought... Cocunuts naturally selected for harder shells because those killed, creating more fertilizer ...
Coconut husks are fairly soft. About like a pumpkin. They're only dangerous because they're so large and heavy.
Dont they clank!
If plants moved faster we would be absolutely terrified of them.
The Day of the Triffids
Attack of the killer Tomatoes!
He means fruits.
Came here for this comment.
Let's not be too hasty...
The kill rate of coconuts cannot be high.
[0] lists 28 documented cases - if we ignore the 5 before 1943 (probably not reliable records), that gives 23 in just over 80 years or roughly one every 3.5 years (although you'd expect that to have increased over time as more people live or tourist near the trees)
Of those 23, 5 were infants (<3y), 1 was killed by 4 coconuts, 1 was killed by a bunch of 57 coconuts(!), and 2 were accidentally killed by their harvesting monkeys.
[0] https://en.wikipedia.org/wiki/Death_by_coconut
> 1 was killed by a bunch of 57 coconuts(!)
I'll raise you this:
https://www.bbc.com/news/world-europe-66429342
I was in south India for about a month and I heard of 1 person dying from a coconut during that time period and heard it wasn’t unheard of. Not a lot of people die but plenty of folks get injured.
Wouldn't animal scavengers pick the carcass clean long before it rots?
That still counts if the scavengers poop nearby.
Usually, animals move around while digesting. They don't just eat the food, immediately digest it, and poop on the spot like a cartoon.
Maybe poisonous plants aren’t always protecting themselves.
“None of you seem to understand. I’m not locked in here with you. You’re locked in here with me!”
The size of insects has decreased over time, correlating with a drop in atmospheric oxygen levels. Maybe this has also happened to carnivorous plants?
As the article points out: If conditions exist for "high-quality plant growth" (correct light, soil, moisture, etc) then plants don't make weird adaptations like eating things/water-conservation methods.
However, if those conditions DON'T exist, then it's hard for plants to get very big.
There's also this: the larger a moving creature you're trying to capture, the more resources you need to invest in the trap. Bladderwort exists everywhere because it's easy to trap small/microscopic things. Giant bear-eating plants exist nowhere because consistently trapping a bear with just leaves, sap, and stems is really fucking hard.
At a certain point, the plants reach an equilibrium where the effort is worth the end result, but diminishing returns if they got larger.
One can imagine some pretty twisted stuff, but anyway large mammals tend to have enough brains to learn to recognize dangers without, or failing that, with evolution (think innate fear of snakes).
this is a secondary mechanism. Falling branches kill and therefor get fertilizer.
If you want to speculate about that, then how about the bamboo die-off cycle? Imagine if you lived in the PNW or Appalachia, and every 120 years the entire side of a mountain launched an army of hungry rats at you. Starves all those cute smug “panda” gluttons too.
Reminds me of a semi-plausible mechanism for carnivorous flora from this [0] Worldbuilding Stack Exchange answer by ckersch:
> Bonegrass is a white fungus which grows in wheat fields. Most of the time, the bonegrass fields are normal wheat fields, indistinguishable from other wheat fields except for their exceptionally high yields and relatively low numbers of animal inhabitants. Of course, this entices lots of animals, large and small, to move into the area. Populations boom, fueled by the seemingly unnatural abundance of the wheat.
> And then the bonegrass blooms. Overnight, huge mycelial mats below the wheat fields become active, with white fungal growths growing up the stalks of the wheat plants, using their stalks for support. Then, simultaneously across hundreds of square miles, the bonegrass releases its paralytic spores. Within 12 hours, the wheat fields become pale, white places of death. The fungus then begins to grow over the paralyzed creatures, flooding their body with neurotoxins that keep them immobilized until they die from dehydration over the next few days.
> The dead animals quickly break down, broken apart by the fungus. As suddenly as the bonegrass grew, it will then die back, shrinking back beneath the earth, where it will slumber as the land above it slowly repopulates, drawn by the seeming gaia above the soil, and unaware of the horrors slumbering beneath...
Scary stuff. Symbiotic plant-fungi or plant-bacteria relationships seem like plausible mechanisms for "carnivorous" plants, even if it's not "plants directly eating people" a la Little Shop of Horrors. There are more good answers with a similar premise under the same SE question.
[0] https://worldbuilding.stackexchange.com/questions/38354/how-...
If you liked this you should watch the animated series Scavengers Reign.
It’s about astronauts crash landing in an alien planet, where the flora and fauna have a symbiotic relationship, and what happens when humans appear.
Fantastic show.
I bought a tiny Venus Fly Trap once, left it in the kitchen, and went away for a weekend.
When I came back the kitchen was buzzing with flies, and the plant had literally gorged itself to death.
This was extra impressive because none of the windows were open. It had somehow leaked attractant scent through gaps I didn't know existed and the flies - not exactly numerous where I was - must have been aware of it from hundreds of yards away.
Point being the plants may be small, but they can be very good at what they do.
I wouldn't think it gorged to death because the leaves close around the fly while digesting. I have a few small Venus fly traps as well and the greenhouse I bought them from said they are really easy to kill with too much or too little water, even just using basic fertilizer. Just speculating of course. These plants are cool but feel so alien.
But yeah they definitely can attract a lot more flies than they can eat and can make the fly problem way worse
So what you are saying is that a Venus fly trap can actually make a fly problem worse, by attracting more than it can eat?
As soon as a carnivorous plant gets big enough to be eating young mammals, it hits the Mama Bear barrier. With motivation, even a tiny mammal can do an enormous amount of damage to a plant.
Some carnivorous plants do eat mammals. Though not primarily, some pitcher plant species have been known to eat mice, for example.
I would have thought that plants which ate neighboring plants, for their easily accessed nutrients and to protect their own access to sunlight, water and forest nutrients, would be pervasive.
I have heard of chemical/strangling/parasitical type competition. The banyan tree is territorial, for instance.
But we would need another name, other than territorial, carnivorous or vegetarian, to describe plant predators which overtly, actively fed on the physical structure or leaves of fellow plants.
There are many parasitic plants, like the well-known mistletoe, which eat other plants. Unlike mistletoe, some of the other parasitic plants have given up completely on phototrophy, depending only on the nutrients sucked from the host plant.
It is likely that there are much more parasitic plants than carnivorous plants.
Plants that feed on other plants must do it similarly to a fungus, by penetrating them and growing into them a root-like organ, for sucking their fluids.
A plant could not bite and chew another plant, because, like the fungal cells, the plant cells have abandoned their ancestral animal-like mobility, by covering their cells with walls made of cellulose, which prevent cell mobility. While there are a few plants capable of infrequent fast movements, like the Venus flytrap, they use special tricks for creating tension in an elastic structure, like when drawing a bow, which would not be suitable for sustaining a sequence of movements.
> A plant could not bite and chew another plant, because, like the fungal cells, the plant cells have abandoned their ancestral animal-like mobility
I would think capabilities like that would be recoverable, if the biological economics worked.
But your point that parasitical plants continuously live off other plants, i.e. they essentially farm them, resolves that. Given victim plants can't run away, their metabolisms are worth far more than any one-time resource extraction.
Rent seeking economy = parasitism
I think the problem is that then you need two energy harvesting systems, and there's not just that much to eat nearby.
I guess to effectively live a long life by eating other stuff, you need to be able to move, or what you eat need to be able to move to you.
Nah. Eating and reproducing lots, fast, is a viable means. See: much of the fungi kingdom.
I suppose you could view the passive offspring dispersal system (wind, current, animal digestive tract, raindrops, etc.) as a form of intergenerational movement.
We haven't had an unscheduled total eclipse of the sun with people singing in the background yet.
have they tried feeding them alllll niiight loooong
Larger animals tend to more intelligent - presumably there’s a natural limit to the size of prey a carnivorous plant can reliably catch from a static location.
Larger animals are highly undesirable prey because they tend to be able to free themselves from a carnivorous plant (low value), with a high probability of severe damage to the plant in the attempt (high cost): they can just walk or climb away, but also involuntarily break a stalk with their weight, tear open a sac with talons, rip away slowly regenerated adhesive parts, eat something that should be dangerous, and so on.
Counterpoint: mice and at least one monkey baby have died in pitcher plants in the wild.
Isn’t this still just the original point though, mice ain’t that big!
We're using different criteria for "big".
A lot of pitcher plants evolved to be a toilet for shrews.
OK, let's see. You're a plant, so you have photosynthesis. It allows you to tap around 5W (averaged out) per square meter of foliage by just AFK-ing. Your major need: water, you have to evaporate it for the photosynthesis to work. But it's not a problem in your habitat, there's plenty of water available.
You also need nitrogen, phosphorus, and other nutrients, but comparatively little of them. Nitrogen is the toughest one. This is the one that you can easily get from animals, though. So you can evolve a complicated mechanism to trap small animals and digest them for nutrients. It also provides you with a bit of energy, but it's completely immaterial compared to photosynthesis, so you don't even bother evolving all the complicated protein-to-glucose pathways.
Now, you want to grow bigger. How would you do it? Energy is not an issue, the photosynthesis provides plenty of it. But you need to trap more or bigger animals, and that's an issue. There just aren't that many of them, and you can't just get away with simple traps anymore.
Is nitrogen really the bounty, not phosphor? I imagine nitrogen fixation is basically the same problem everywhere, equally distributed through air, but phosphor depends on geological processes, depends on the mineral make of the soil. If phosphor gets depleted, you have two options: Wait for mountains to grow and shed some, or indulge in someone else’s DNA and ATP. Maybe the acidic soil makes uptake harder, or aids wind and water erosion?
Looking at my spotted windowsill, if I was a plant on an evolutionary adventure, I‘d befriend some spiders and turn my crown into a cotton candy guano cloud. I‘d rather have the animal predators do the work and then have them shit in my yard for the nitrogen and phosphor. You only need twigs and then some bioluminescence or stink to help those spiders fill their nets.
Have a fungus rot my legacy core wood so an owl can defecate a hectare of mice and squirrels right into my tummy. Or you look all mighty and judgmental so these funny naked apes drench your soil in the blood of goats and their youths. Is that still a thing?! What about instagramable forest cemeteries? Heard about the tree toilet TikTok challenge? So fun! Super healthy and natural too.
Now thinking of it, I wonder how many plants encourage animals shitting and dying in their yards. Maybe it’s not deterrent, but enterotoxic payment options?
I guess, unless your objective is to grow impractically large fruits, because your human creator couldn’t keep it in their pants, for most plants in most places, neither phosphor nor nitrogen side hustles are really worth the effort.
Yep, nitrogen is the limiting nutrient in swamps. It can be fixated only through biological means, while phosphorus is produced by weathering rocks. Nitrogen fixation is suppressed in swamps, while phosphorus is typically still available from the inflowing streams.
Wikipedia says it's both nitrogen and phosphorus. https://en.wikipedia.org/wiki/Carnivorous_plant
> It can be fixated only through biological means
I don't think this is very correct, but why do these biological means fail in bogs/swamps? Kinda my point: Other plants and ecosystems figured out the nitrogen problem all over the world. It's more or less the same everywhere, since nitrogen naturally comes from the atmosphere. AFAIK, there are more or less three ways to have nitrogen input into an ecosystem: Lightning, biological fixation in plants/microbes and artificial synthesis/fertilization.
I suspect the swamp ecosystem has something going which makes nitrogen fixation difficult. All other plants in the swamp need nitrogen to grow, too, how are they doing? Maybe it is the (often) low pH, maybe it's a lack of trace metals for certain enzymes. Maybe the anaerobic conditions favor inaccessible conversion of nitrogen in decay.
Nitrogen can't be completely exhausted, because you have (low) constant influx from the atmosphere everywhere on Earth's surface, even without biological fixation. Phosphorus, on the other hand, can be effectively depleted. The "cycling" of phosphorus happens on geological timescales. A low soil pH may leech out the phosphorus from minerals and have it carried away by wind and water.
I still don't think plants would go the carnivorous route just for the nitrogen. If anything, I suspect they recycle the "nitrogen" as amino acids to save on synthesis. Some carnivorous plants apparently secrete phosphatase into their prey. That's a lot of evolutionary effort...
Carnivorous plants certainly don't mind extra phosphorus, but it's usually not limiting.
> I don't think this is very correct, but why do these biological means fail in bogs/swamps?
They don't. Moreover, the anoxic environment of swamps actually promotes the nitrogenase activity. However, the constant presence of water also diffuses the nutrients, and denitrifying bacteria use ammonia as an energy source. In oxygenated environments, they are typically outcompeted by regular air-breathing bacteria.
This happens in regular soil, but it's normally not saturated with water, so nutrients are not constantly washed out.
> All other plants in the swamp need nitrogen to grow, too, how are they doing?
Not very well. Swamps are not very productive biologically. There is _some_ nitrogen available, it's just that its equilibrium concentration is much lower.
Thank you. TIL.
> Now thinking of it, I wonder how many plants encourage animals shitting and dying in their yards.
All it takes is to make your forest more attractive to bears than the Vatican City is.
Bears are notoriously suspicious of ritualized worship, so... low-entropy solution achieved.
They don’t fit into the pews. Humans design them to be inaccessible to bears. It’s discriminatory. The cats stay away because they get bored easily by people talking about themselves or other people instead of about cats.
> then have them shit in my yard for the nitrogen and phosphor.
Nepenthes Lowii says hi.
"However, pitchers produced by mature N. lowii plants lack the features associated with carnivory and are instead visited by tree shrews, which defaecate into them after feeding on exudates that accumulate on the pitcher lid."
[0] https://royalsocietypublishing.org/doi/abs/10.1098/rsbl.2009...
Great, another business idea for the bin.
Still, I kinda want to see a tree's light faintly glowing through their guano cloud of horrors. You could plant them next to lakes and such to get rid of mosquitos! But mostly for the eerie atmosphere, to make man afraid of the night again. Whispers of ten thousand feet, be wary of the lantern trees!
The article doesn't seem to talk about it but many carnivorous plants lost part or most of their chloroplast genomes: https://pubmed.ncbi.nlm.nih.gov/30629170/
I.e., because they got their nutrients from animals they didn't need chloroplasts and the chloroplasts 'broke' over time. Chances are minimal to zero that carnivorous plants will regain chloroplasts. In a way, carnivory in plants is an evolutionary 'dead end' similar to parasitism, which is also often linked to chloroplast loss. Where could the plants evolve 'to' if they have no chance of getting energy from alternative (chloroplast) sources?
>Most of this carnivorous botany is small, but the diversity of different trapping mechanisms raises an evolutionary question.
Isn't the obvious conclusion that: 1. There are many peaks in the fitness hypersurface for plants that correspond to meat eating 2. The peaks have smooth gradients at the outskirts 3. All peaks are minor local maxima
1 is because low nitrogen alone is not enough to make carnivory a net positive contributor to fitness. You need additional factors to make the gradient positive to begin with. That means the peaks (niches) are random and narrow.
3 is because carnivory implies an arms race against prey defenses, competing scavengers, and competing predators. Specialist animals are at a large advantage against plants, especially if meat is still a side dish to sunlight.
To me the interesting question is 2 - most plants don't digest animals at all, so how does this begin to evolve?
> Some large carnivorous plants are alive out there, but none is big enough to make a meal out of you.
Clearly these researchers have never been to the Mushroom Kingdom.
Mushrooms technically are not plants
„Technically“… talking kingdoms :D
Like, an orca is more fish, you are more fish (or fungus for that matter), than a mushroom is a plant.
We are more mushroom than plant as well.
The piranha plant is native to the Mushroom Kingdom, reaching sizes up to several stories tall.
Plants technically are not mushrooms https://en.wikipedia.org/wiki/Piranha_Plant
How about: larger animals can learn from seeing others eaten, so they won't fall for the trap.
I mean, that's a weak evolutionary argument against all forms of predation/prey. It assumes a level of cultural/shared knowledge that doesn't typically exist. Also, size =\= intelligence/problem solving. Chimps and humans are both smarter than gorillas.
Yes, troop 1 of monkeys have learned about the monkey-eating plants that have evolved overnight, but troops 2-10 haven't. Eventually troop 1 leaves the deadly forest, and troop 2 comes in. After a few seasons, they notice these fucking plants keep eating their babies (again, most predators go after babies for the reason you mentioned, they haven't learned how to avoid death yet) and then they move on. Repeat for several centuries. Behold nature in all its splendor.
I like the article's ideas: If you can grow large enough to eat a person, you're getting enough nutrition that you don't need to eat a person.
A related question is why plants in general can thrive on such tiny amounts of protein. (Nitrogen)
Simple. They don't need that much nitrogen.
I'd be surprised if your tomato plant "ate" a whole teaspoon of fertilizer in its entire growing season.
One day it'll The Day of the Triffids
Plants not being able to chew or tear their prey is a big disadvantage.
Not if you're prey. i'd rather not have more stuff trying to eat me :P
Baleen whales seem to do just fine without it.
I guess there are still some things that we can be grateful for.
https://www.youtube.com/watch?v=RuzLXxbGc4c
Because a fly can spit on your food, but a mouse can eat a hole in your baseboards.
I used to think carnivorous plants would someday grow huge and eat people like in the movies. Turns out they have always stayed small and just got really clever instead.
This piece made me see it differently. Not growing big is not a flaw. In a place with barely any nutrients, surviving with just a bit of strategy is actually kind of amazing.
tl;dr Basically a lot of sorry excuses.
If you're a plant, don't buy into the negativity. Work your way up the food chain. If you eat it, then it's your food.
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