It’s Nasty: Thigmonasty (Greek thigma for touch and nastos for pressed close).

It’s Nasty: Thigmonasty (Greek thigma for touch and nastos for pressed close). Closure of the Venus flytrap (Dionaea muscipula), at 40-100 milliseconds, is one of the fastest movements in plant kingdom. Little surprise that it involves action potentials: electrical signals typical of nerve communication in animals. The trap is triggered when at least two of the tiny surface hairs are touched by an insect or spider within 20 seconds of each other. Since the movement costs energy, this coincidence of two stimuli safeguards against waste from accidental triggers.

There’s no chemistry: Unlike chemical signals, like hormones, action potentials can fire within a millisecond and propagate rapidly over long distances. Although plants have the basic necessities for electrical signaling (ion channels, motor proteins), they have nowhere near the sophistication achieved in animals. Still, an action potential can achieve speeds of up to 40 m/s in plants and is used to respond to environment.

Touch me: The first step is the opening of mechanically-sensitive ion channels that sense deformity of the hair. This causes the cell membranes to depolarize by reducing the distribution of charges across the cell. If this depolarization exceeds a certain threshold, additional chloride and potassium channels open to let in more ions. Movement of protons makes the cell wall acidic, allowing it to soften and let the cell elongate rapidly. Despite intensive study for ~130 years, the exact mechanism of signaling is not clear.

Food fight: Recently, the digestive juice of the Venus flytrap was analyzed and found to closely resemble enzymes used in the fight against pathogens, rather than the digestive enzymes of animals. This suggests an evolution from defense pathways to food acquisition in carnivorous plants. Read more:

The Doors – Touch Me

An early submission for #sciencesunday since I will be traveling tomorrow (Viva Barcelona!).

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100 Responses to It’s Nasty: Thigmonasty (Greek thigma for touch and nastos for pressed close).

  1. Wow!  Have fun in Barcelona!

  2. Rajini Rao says:

    Yes, I hope to! Thanks, Linda Hedrick 🙂

  3. !Que tenga un buen viaje, Rajini Rao !  Hasta la vista otra vez…

  4. Rajini Rao says:

    Wonderful link, thanks Linda Hedrick . I read somewhere that there are more of these bred than in the wild. That’s one way to preserve them.

  5. Kawthar A says:

    Great post! enjoy Barcelona, it is a very beautiful city (as i was told by my friend). Rajini Rao 

  6. Rajini Rao says:

    Thanks, Feisal Kamil . Leaving in a couple of hours 🙂

  7. John Simmons says:

    if it tastes bad it’s usually good for you!

  8. Rajini Rao says:

    Do people eat Venus Flytrap, John Simmons ? O.o

  9. Roki Hassan says:

    this plant need protein……. 

  10. Chad Haney says:

    Don’t forget Ray Manzarek of the Doors used a Gibson Kalamazoo.

  11. Chad Haney Thanks for the Manzarek information. Chad.

  12. Barcelona? So close, so far. Enjoy. 🙂

  13. Jason Wold says:

    Fascinating read. Thanks for sharing.

  14. Rajini Rao says:

    Taking my camera, Kimberly Elaine . Víktor Bautista i Roca has offered to be my guide and the conference organizers have some sightseeing planned as well. Excited…

  15. I used to own a venus flytrap.  Such a cool plant.

  16. When I was little….. I bugged my Bio professor asking how this plant manages sudden movements without the presence of muscle tissue…..


  17. Ooh, we had a mere two days in Barcelona last year – fantastic place! Have a great time, Rajini Rao!

  18. Rajini Rao says:

    Good for you, AsHisH Kulkarni ! There is the mechanics of the midrib and two lobes, there is change in turgor pressure (water movement following ions, by osmosis) which changes stiffness, and there is the lengthening of individual cells rapidly, due to pH changes. No muscles required 🙂

  19. Rajini Rao says:

    I’m only there for a couple of days as well, David Archer . Back by Wed. Thanks!

  20. I had several of these plants as a kid – I do recall the (very plant-like) slow recovery to reset the trap (I think I tired them out a lot).

  21. There are quite a few fantastic plussers in Barcelona, you can always give a shoutout if you need more fun. 😉

  22. Chad Haney says:

    Rajini Rao I never got around to posting the picture of the Madagascar jasmine wrapping itself around the rose of Sharon.

  23. Rajini Rao says:

    I didn’t find numbers for the recovery rate, David Archer , so thanks for that info. Will do, Daniela Huguet Taylor 🙂

    Thanks, Cindy Carpenter .

  24. Rajini Rao says:

    Chad Haney , if you do post the jasmine, label it Thigmotropism for touch sensitive growth. There is that fantastic cucumber tendril story on SciFri  that I think you shared on ScienceSunday a couple of weeks back. I was thinking of cajoling a gif out of the movie and attempting to explain the mechanics of touch sensitive growth (as opposed to movement).

  25. Chad Haney says:

    We talked about it a few times. Maybe we should have another round of tag-team ScienceSunday.

  26. Rajini Rao says:

    Good idea, you may be able to decipher more of the mechanical aspects of the cucumber tendril story that went whistling through my brain 🙂 I’ll ask Kevin Staff to make a gif for us.

    I love the collaborative aspects of G+.

  27. dora chiabov says:

    Funziona anche contro le zanzare? 

  28. Rajini Rao  – I understood it clearly when u told it… but was a little hard to imagine for a 14year old 😛

  29. Rajini Rao says:

    dora chiabov , it eats mosquitoes and other insects.

  30. Probably not, dora chiabov – there are attractants (aren’t there?) for flies in the plants, but they probably wouldn’t attract mosquitoes / zanzares! 

  31. Rajini Rao says:

    I may have misunderstood the question David Archer , was she asking if there is a chemical attractant for insects?

  32. She just asked if it works on mosquitoes; unless it’s exhaling CO2, it probably wouldn’t be a big draw for zanzares. 

  33. dora chiabov says:

    Grazie per il chiarimento. Ma quante ne occorreranno per liberarsi di tutte le zanzare in una notte d’estate..

  34. Moltissimi, credo! dora chiabov 

  35. Deeksha Tare says:

    Wow Rajini Rao 🙂

    You’re the Queen of Science on G+!! m/

  36. Chad Haney says:

    Did someone say nasty? I’ll pretend that Feisal Kamil left this comment.

    Vanity 6 (Soul Train) Nasty Girl

  37. Chad Haney says:

    Hey Lindsay Leonidas what’s the name of the plant you bought that catches gnats?

  38. Chad Haney , its a butterwort. I just bought 3 more online too.

  39. Chad Haney says:

    te he Feisal Kamil 

    Thanks Lindsay Leonidas 

    Here’s the Wiki on Butterworts.

  40. No Idea how I found Rajini Rao on G+ but I am so glad I did. Every post is a treat. Undisputed queen in sharing fun and interesting  science information. Thanks a lot

  41. Chad Haney says:

    Ramesh Sundararajan give ScienceSunday a spin. There’s plenty more science on G+.

  42. Rajini Rao Just a silly side note. It is “Visca Barcelona!”.

  43. Is it wrong that I laughed at this? 😛

  44. Chad Haney says:

    Yes Chris Mallory because you love all bugs. Right?

  45. Chad Haney Yeah but I love plants too 😛 Plus I don’t choose sides when it comes to nature.

  46. Chad Haney says:

    You’re too complex Chris. I can’t keep track anymore. 😉

  47. I suppose that’s a good thing, I gotta keep you on your toes!

  48. Rajini Rao says:

    Chris Mallory , was that a left over fly leg from the trap’s last meal on there? It’s a bit gruesome to think that it hadn’t even finished digesting the last meal before it goes for another. 

  49. Didn’t even see that until you mentioned it! Yep, definitely an insect leg, surprising it hasn’t been digested yet. Perhaps it got snagged off of one that got away.

  50. Rahul Joshi says:

    Amazing how these plants have perfected the entrapment. It isn’t easy to kill a mocking fly. They (usually) fly backwards to avoid the obvious trajectory by any predator. Not for this fangy beast though!

  51. Nice, its response is amazing ……technique should be studied,may be helpful for self assembly in nanotechnology…

  52. Such a big fly in these tiny leafs….hmmmm… size doesn’t matter…!!!

  53. mahek abbas says:

    mimosa pudica  is also an example of thigmonastyy

  54. Wondering how big these plants can get & I’m thinking Science Fiction 😉  (hope your having some fun)

  55. Cheryl Ann MacDonald how nice is ur science fiction…I m amazed !!!

  56. 🙂 My Science Fiction writing is 🙂 all in the imagination Avinash Dixit. I am hoping someone else will have the time…two of my favorite subjects “Science” and “Psychology” all throughout the movie. (Maybe Raj will help 🙂 )

  57. Cheryl Ann MacDonald movie..? means u r writing a story for..


  58. Can this plant solve the problem of mosquitoes…

  59. Rajini Rao says:

    Avinash Dixit , check the comment stream above for an answer to your question 🙂

  60. Geet Vadher says:

    bhu j saras 6……….

  61. fantastic……………………

  62. Rajini Rao says:

    Grazie, Mariano Bucolo 🙂

  63. Rajini Rao says:

    Was the smell from undigested meat in the trap, Thex Dar ? It would be interesting if the smell associated with the plant itself changed.

  64. Rajini Rao says:

    Haha, I misread that actually, I thought that Thex Dar liked the smell 😀

  65. Rajini Rao says:

    That’s really interesting from a biochemist’s point of view. Meat is rich in nitrogen and the breakdown products of proteins (urea? uric acid? ammonia?) must have contributed to a distinctive smell. Even people smell differently, depending on what they eat 🙂

  66. Chad Haney says:

    Thex Dar I read a similar article that dogs smell mostly what the flora and fauna on us eat. What makes each person smell unique is the combination of what we eat, what bugs we have on us, and what they eat.

  67. Rahul Joshi says:

    Even I read that as “I liked it”. LOL!

    Thex Dar I used to hear this on forums a lot that Westerners found Indians smelling of curry. I thought it was a joke until I visited a fellow colleagues’ home. I’m guessing besides the eating part, it also has a lot to do with American kitchen ventilation which isn’t the best when it comes to dispelling strong Indian spices.

  68. Rahul Joshi says:

    Electric chimney system is a relatively new concept here in India. Till 90’s, the ideal house was considered the one where wind could blow through one end to another. Auto ventilation! My dad still swears by it, dust and pollen irrespective 0_o

  69. Rajini Rao says:

    Anything that I cook tastes Indian. Perhaps I should stop putting turmeric into everything? LOL, I’m exaggerating a bit, but what you say about ventilation is so true. Thex Dar , I’m sure you were charming to the females even without the chocolate 🙂

  70. Rahul Joshi says:

    No compromises on turmeric Rajini Rao ! You should probably try silencing a few DNA here n there instead 😛

  71. oh……..Nature automatic ma sheen………!

  72. I had already seen it (and it’s very cool!), but thanks for mentioning me Anne-Marijke Scheyltjens! 

  73. Mandy Allen says:

    Thanks very much for tagging #buggylunch Anne-Marijke Scheyltjens! This is very interesting to see.

  74. Jean-Yves says:

    Thanks Anne-Marijke Scheyltjens for tagging us 🙂 And thanks Rajini Rao for sharing!

  75. Arnav Kalra says:

    Urmila Sharma nice gif

  76. GS SODHI says:


  77. Rajini Rao says:

    Di A , do give us an update here if you dig up anything! There are pH and volume changes in the cell wall to allow for mechanical bending. So quite possibly, fluid movement as well through water channels (aquaporins). 

  78. Rajini Rao says:

    Oh dear, this is such an old post, I’ve forgotten whatever shenanigans took place here 😉

  79. Chad Haney says:

    Shenanigans? What? not possible..

  80. Rajini Rao says:

    Even I blush when I read through old comment threads, Chad Haney 😛

  81. Chad Haney says:

    Yeesh, maybe I should re-read the comments.

  82. Rajini Rao says:

    I would strongly advise against doing that 😉 

  83. G+ is a strange place some times… over the past week, about 3 posts from 2012 have burbled up to the surface again.

  84. Chad Haney says:

    David Archer, it’s been happening on and off for me. There are periods where nothing new shows up, just old posts. Then it mysteriously resets the clock.

  85. Rajini Rao says:

    Now that YouTube videos are linked to our G+ accounts, I get the odd plus on old music shares too. I quite like “the burbles”, actually.

  86. Chef Izzy says:

    I love these plants.

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