Venus flytraps ‘able to count’ in order to avoid false alarms, study finds

Jan 22, 2016

Photo credit: Adam Gault/Getty Images/OJO Images RF

By Press Association

Venus flytraps can count, according to scientists who tested the carnivorous plants and found they use their mathematical skill to conserve energy and avoid false alarms.

Researchers in Germany learned that the Venus flytrap adjusts its feeding behaviour according to the number of times the sensitive trigger hairs on its special leaves that resemble spring traps are stimulated.

“The carnivorous plant Dionaea muscipula, also known as Venus flytrap, can count how often it has been touched by an insect visiting its capture organ in order to trap and consume the animal prey,” said lead scientist Prof Rainer Hedrich, from the University of Wurzburg.


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41 comments on “Venus flytraps ‘able to count’ in order to avoid false alarms, study finds

  • @OP – Researchers in Germany learned that the Venus flytrap adjusts its feeding behaviour according to the number of times the sensitive trigger hairs on its special leaves that resemble spring traps are stimulated.

    If an insect touches one trigger nothing happens but the trap is sensitised. If it touches a second trigger, the trap closes like a cage around it. I would suspect that it is the insect moving around trying to find a way out which triggers digestion.
    In any case the trap will close more firmly after a few minutes and immobilise the insect.

    If a trap is closed by some passing wind blown debris which does not continue to struggle, it simply opens again within a few hours of a couple of days.

    Traps which digest large insects blacken and die after nutrients have been absorbed, but with very small insects traps may reopen and work again.



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  • I find “counting” and “mathematical skills” in the article a bit of a stretch.

    It seems to act more like a Finite State Machine, a common design in automation, no actual counting required. Each stimulus, from a sensor, is an input, and alters the internal state (represented in a plant by perhaps different levels of some chemical in the sap). Time, without stimulus, “resets” the state, as the chemicals break down or are re-absorbed. Sorry for the imprecise biology/botany here.

    It would be easy to simulate with states that we might label Idle, Alerted, Caged, Digesting. With sensor inputs causing the system to advance to the next state (without any counting), and lack of inputs causing it eventually to move back to a previous state, eventually opening up (if it hasn’t died as the final state of having a Feast).

    At no point is any counting involved. Therefore, some kind of sensationalist reporting, not a great service to the dissemination of scientific knowledge to the general public.



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  • OHooligan
    Jan 22, 2016 at 11:20 pm

    Each stimulus, from a sensor, is an input, and alters the internal state (represented in a plant by perhaps different levels of some chemical in the sap).

    Traps are spring loaded, and held open by hydraulic pressure which is released by stimulating the trigger hairs.

    The traps initially close like a cage around the insect with the fringe comb structures meshing to make the bars, but with further triggering, the walls of the cage close up firmly to grip the insect.

    There is probably some connection between the release of tension in springs, or the reduction in hydraulic pressure, which triggers digestion.



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  • bonnie
    Jan 23, 2016 at 7:48 am

    Venus Flytraps, indigenous to the sandy areas of the Carolinas, were at one point considered endangered.

    Humans pulled specimens from the wild for monetary gain.

    That is typically silly, as they can be easily propagated in cultivation.

    In fact I have had Venus Fly Traps in my botanical collection for decades, and have distributed numerous small plants to interested growers over the years.



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  • Of the insectivorous plants, Venus Fly Traps, Sundews and Butterworts actively entrap insects using moving parts.

    Others, such as Pitcher Plants, have static traps, which lead insects to fall in and drown.

    Of course many plants have moving parts such as the obvious and quick folding leaves of Mimosa Pudica, and the slower tracking of the Sun by the leaves of some trees and some flowers.
    Many insect or animal pollinated flowers, open and close according to the time of day or the weather.



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  • I have observed a tendency amongst the authors of the various articles I have read on this site that deal with animal behavior.
    There is a tendency to seek to obliterate the differences between humans and lower forms of life.—Perhaps it is a desire to rid the world of the distinction itself between higher and lower, the very idea itself of hierarchy, as it were.
    Animals can now speak, and now have language (as opposed to the ability to communicate through sound), can count, add and subtract, multiply and divide, compose and perform music, and this is no surprise; we now now that they possess the ability to think in abstract terms, that is, to form concepts.
    Now we do know that animals can plan for the future, etc, and build nests and dams. Now they can count too
    While the differences between us and them is no doubt quantitative, there is an enormous quantitative difference. And quantity does change quality. But much of what we are calling planning and counting and building, is mere instinct or an involuntary response to stimuli – or a combination of the two.
    As for language, I am prepared to say, finally, that sounds and words are virtually indistinguishable from each other. However, let us not delude ourselves and others, and strive for precision.
    We all like to feel all fuzzy and warm in the idea that our dogs and cats and the birds and the insects are just like us, mommy and daddy, but that is blurring a very important distinction and obfuscating an important idea, to wit: humans stand the highest in the chain of terrestrial “creations” (a 19th Century expression).
    Only humans can be moral or appreciate beauty, or conceive of such things as, say, justice, vanity, nobility, suffering. The brutes do undoubtedly suffer, and appear to have a sense of the future and the past (although they most certainly do not) and may exhibit behaviors that resemble nobility, but this is largely a deception.
    The brutes are finally brutes.
    We are a part of nature and yet capable of separating ourselves from it. (Although I am an anthropocentrist like Kant I am opposed to the exploitation and abuse of nature.)
    The lower animals, finally, have but a faint trace of the most rudimentary form of reason (if even that) and hardly anything you can call real individuality.
    I would also add that the moral and intellectual differences amongst human beings themselves are nothing short of incalculable.
    (I am in a foul mood.)
    Something off the beaten path. Hope you enjoyed my comments.
    I am sure Alan and others will now provide some links that prove that this animal can do this and that animal can do that and that they have individuality and that they are just like us, etc.
    That’s fine. Bring on the links.



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  • We are a part of nature and yet capable of separating ourselves from it.

    First, define “nature”.

    Then, please give one example of how any human animal separates itself from nature?



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  • Man not only exists, my boy; he knows that he exists, can form a relationship to existence itself. Animals cannot. This enable man to choose to renounce his own existence (as well as consciously affirm it). Animals have no such choice. By withdrawing himself from the mass or raising himself up above the mass of nature, with its countless, as it were, manufactured articles (of which he is one), an individual can, to a certain extent at least, transcend nature. He can never do so entirely; nature is also in man. What is nature? I get asked that a lot. You define it. I’m busy.

    Saw a few more typos up there. What would you call a horror of typos, Doug? Is that neurotic?



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  • Dan
    Jan 23, 2016 at 10:28 am

    to wit: humans stand the highest in the chain of terrestrial “creations” (a 19th Century expression).

    Indeed – an ancient an well refuted Biblical misconception.

    The lower animals, finally, have but a faint trace of the most rudimentary form of reason (if even that) and hardly anything you can call real individuality.

    You will have to provide far better evidence than the personal opinions or assertions of some philosopher, to make that claim even slightly credible!

    In evolution there is no such thing as a “higher or lower animal”. There are more complex organisms, and better adapted organisms in the context of individual environments or time-scales, and there are levels of dependence or predation within food-chains.

    I am sure Alan and others will now provide some links that prove that this animal can do this and that animal can do that and that they have individuality and that they are just like us, etc.

    There are far too many to fit onto a discussion thread.

    BTW: I’m not sure what this has to do with the topic of carnivorous plants!



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  • Counting carnivorous plants. That irritated me, although it’s a side issue, I suppose.
    In evolution there is no higher and lower. True.
    But I am not concerned at the moment about what is in or out of evolution: I am a product of evolution, an existing and thinking individual, and have formed my own judgment, my own conception, of higher and lower. That is my right – foolish as it may sound.
    Btw, I enjoy expressing anachronistic ideas. Some are absurd and some may not be. I am not sure myself at times.
    That’s enough out of me as far as carnivorous plants go.
    Talk to you soon, my learned friend.



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  • I got plants mixed up with insects, Alan. Sorry, although that takes nothing away from my point – which was a serious one but not altogether serious.



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  • Hi, Dan.

    Man not only exists, my boy; he knows that he exists, can form a relationship to existence itself. Animals cannot…
    Animals have no such choice.

    First, let me clarify that I’m not a boy, as I am significantly older than 13. (Although I may feel and act – and be treated -like a boy at times, I do prefer being referred to as a man, but I also identify with “adult male human animal”. “Friend” would work, too.)

    Second, saying “man can but animals cannot” is a self-refuting statement as man is an animal. The distinction is false.

    By withdrawing himself from the mass or raising himself up above the mass of nature, with its countless, as it were, manufactured articles (of which he is one), an individual can, to a certain extent at least, transcend nature. He can never do so entirely; nature is also in man.

    Where is this place “above the mass of nature”? How is it “above”?

    What is nature? I get asked that a lot. You define it. I’m busy.

    I was sincerely asking what is your definition in order to better understand (and perhaps challenge) your earlier comments. But as this conversation has apparently moved “off topic”, I won’t insist. I’m sure there will be other opportunities.

    Saw a few more typos up there. What would you call a horror of typos, Doug? Is that neurotic?

    Some would say so (but that doesn’t mean it’s true). Typos tend to bother me, but I understand how and why they happen and I am usually forgiving of those who produce them. I am usually disappointed in myself when I make them, but eventually forgive myself.

    Stay safe, Dan.



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  • Just kidding around, Doug when I said “my boy.” No offense. Just playing the part of a pompous (yet truthful) ass.
    Man is of course an animal, a human animal.
    I simply do not have the mental energy or patience right now to define nature, although I can. Sorry. A very large question. Some other time. No one definition will satisfy everyone, btw.
    I have been reading your comments, like and appreciate what you have had to say.
    See you around.



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  • Dan
    Jan 23, 2016 at 12:18 pm

    I got plants mixed up with insects,

    That’s what the Venus Fly Traps do! –
    (Get mixed up with digesting insects!)

    Another interesting feature, is that if you leave a pot of Venus Fly Traps in a room with kids, all the traps have closed when you come back even though there are no flies in them!!! 🙂



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  • Dear Moderators,
    Once again, I’d like you to consider deleting this long comment I just wrote below. I know you’re busy and perhaps it should stay up as a sort of punishment, but it was written impulsively and while it may have some iota of merit I feel very embarrassed by it. The other subsequent exchanges can stay or not. Up to you.
    But this monstrous comment belongs elsewhere or perhaps nowhere.
    At least let this admission stay posted.
    Thanks very much. I have strayed once again. No real harm done. —I Just feel silly.
    -Dan the Prodigal Son



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  • It’s the long one below. I went off on a tangent. Maybe you can just leave it. Since I acknowledged that it’s a little out of place in my note to you I think it’s okay.
    I am really sorry I bothered you guys with this trivial self centered crap. Seriously.



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  • Thanks Alan for the extra detail. A Finite State Machine would model all this quite nicely, and a very simple setup connecting the sensors to the hydraulics seems to explain things a whole lot better than “counting” and “mathematical skills”.



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  • I’d like to add something truly substantive, and more to the topic of this discussion, as a way of making amends for my semi-parodic comment below.
    According to my researches the speed of closing of the so-called leaves can vary depending on the amount of humidity, light, size of prey, and general growing conditions – and of course the mood of the plant.



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  • Dan
    Jan 23, 2016 at 5:31 pm

    According to my researches the speed of closing of the so-called leaves can vary depending on the amount of humidity, light, size of prey, and general growing conditions

    The speed of closing does vary a little with temperature, and the speed of re-setting varies with the energy of the plant based on sunlight and temperature.

    The size of prey does not in itself affect the speed of closing, but some large insects are strong enough to fight their way out of a trap.

    Fly-Traps are essentially bog plants, so if they dry out or overheat, they lose leaves and become dormant.
    (All my comments are based on years of personal observations of my own specimen plants.)



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  • Thanks, Alan–
    Btw, that little bit at the end about “mood” was a joke.
    Do you like orchids?
    After reading Rex Stout’s novels I was inspired to buy a few and they always die on me within a week or so.



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  • Dan
    Jan 23, 2016 at 9:19 pm

    Do you like orchids?
    After reading Rex Stout’s novels I was inspired to buy a few and they always die on me within a week or so.

    Orchids are one of the types of plants which are highly adapted to manipulate insect pollinators, but some really need a heated glasshouse and careful knowledgable cultivation.
    I don’t grow any, but a friend of mine does.



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  • Orchids have taken Ikea by storm and once proud plants are being sold cheaply by the dozen. Supermarkets have caught on too and orchids are being abused by the millions. My wife’s shopping included three per month until I decided to get involved and get them to flower again. The instructions said, water every two weeks. The poor plants were gagging for water and feed.



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  • phil rimmer
    Jan 24, 2016 at 6:58 am

    The thought of “orchid murder” brings tears to my eyes.

    It is normally death through neglect or mismanagement by amateurs!

    Physical dismemberment by professionals is an active method of commercial propagation.

    http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.467.6712&rep=rep1&type=pdf

    A commonly held view is that the ideas and basis for the practice of orchid micropropagation arose de novo in 1960 from the work of Georges Morel in France. In this paper we argue that the crucial developments in micropropagation were made by Gavino Rotor in 1949 in the USA and Hans Thomale in 1957 in Germany, and that Morel’s work needs to be seen in the context of a long line of research achievements in the in vitro culture of a wide range of explanted tissues and organs from plants of many species. A critical, historical, analysis of the events as they relate to clonal orchid multiplication is offered here. Two important technical innovations for orchid micropropagation — the use of activated charcoal to darken nutrient media and the adoption of liquid culture environments for part of the process — are examined in detail. In addition, an unusual US patent claiming invention of ‘a method for rapidly reproducing orchids’, especially cattleyas, is analysed.



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  • Laurie, Oh Laurie,
    You should read the marvelous Rex Stout (1886-1975). Orlean may have been a fan. “One is inevitably reminded of Rex Stout’s great eccentric detective Nero Wolfe, whose very oddity was symbolized by his obsession with orchids.”
    (I looked up The Orchid Thief, found a review with no name attached to it, as usual!)
    He was the greatest (or my favorite) detective novelist – not including Conan Doyle. His character Nero Wolfe is a fat crime-solving genius who rarely leaves his office, loves to eat, and tries to solve the cases without having to get up from his favorite chair. His assistant Archie is a great character.
    Anyway, the eccentric Wolfe (like Stout himself) is an orchid collector. He visits his plant room every day at a certain time, and he is not to be disturbed – by anything short of a real emergency.
    Google Rex Stout / Nero Wolfe
    P.S You expect me to read something? What about the one I recommended, Before Adam? That’s right up your alley.
    P.S. Try not to read this comment below. I think I was half asleep.



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  • Dan

    No, no, I don’t expect you to read that. Just mentioning it because it was quite a cool book about a weird little world of orchid collecting weirdos. They made a movie from the book called Adaptation. I have a list of books to read that is a mile long. Then I’ve gone and bought another one on Amazon today:

    Genomic Imprinting and Kinship (The Rutgers Series in Human Evolution, edited by Robert Trivers, Lee Cronk, Helen Fisher, and Lionel Tiger)

    This one I HAD to have because there is a symposium coming up in March at Tufts U. and the author of that book, David Haig is on the panel. Then I saw that author Susan Jacoby has a new book coming out and that she’s speaking at Harvard Book Store that same week so now I need to read that one too!

    Strange Gods: A Secular History of Conversion Kindle Edition
    by Susan Jacoby (Author)

    I admire her writing very much and have several of her books ready to be signed by her. I’m looking forward to meeting her at that event.



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