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TRNC84 t1_j6ker2v wrote

Reply to comment by sgame23 in Venus fly trap on the hunt by c0ntr0ll3dsubstance

So what happens if you like poke the mouth does it close? And if so does it know to open back up if it caught nothing?

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pees_on_dogs t1_j6kj9br wrote

Yes, it'll close, but this is bad for the plant. It takes a lot of energy for them to do this, so if they catch nothing its a problem. Don't try and make them close for no reason.

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wiseroldman t1_j6kutcp wrote

Would heavy rain have the same affect and make the mouths close?

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RainboBro t1_j6kz1st wrote

>Gentle rain can close traps, but this is not a common event. The necessity of two or more stimuli to close a trap accounts for traps general lack of responsiveness to raindrops in light rainfall. Traps observed to be closed by raindrops began reopening in an average of 4.5 hours and full reopening averaged 15.8 hours.

>Only 6 to 12% of the traps in the field of view were closed by intense rain. Even rain so heavy that the traps were submerged in water left most of the traps open. Gentle rain can close traps, but this is not a common event.

  • Research Gate

https://www.researchgate.net/publication/352295766_Can_Venus_flytraps_be_triggered_to_close_by_raindrops#:~:text=Only%206%20to%2012%25%20of,is%20not%20a%20common%20event.

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wiseroldman t1_j6l03ty wrote

Interesting, so the plant has evolved to deal with the stimulus from rain drops. Thanks for sharing!

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reddragon105 t1_j6kuzwx wrote

This is the thing that blew my mind about them when I first got mine - they actually have a built-in timer to make sure they caught something living, and thus worth digesting.

When something first lands in one of the traps and touches a trigger hair, the plant does nothing - it has to sense two trigger hairs being touched within 20 seconds for it to snap shut, and then it has to sense more hairs being triggered - five in total - in order for it to tighten even more and then start digestion.

The video above actually only shows the first stage of the trap closing - if it was 30-60 seconds longer you would have seen the trap shut tighter, so there were no gaps left, as the flies kept moving around inside.

If a trap was accidentally triggered without live prey inside (like by a rain drop), or a fly managed to get out in time, then the trap would shut but when the plant didn't detect anything still moving inside it would open again slowly - takes about a day or two.

But don't trigger them on purpose - it takes a lot of energy for the plant to close and reopen them, and if it's not getting any food from the effort it could kill the plant.

The traps themselves can last for a few months before dying off and being replaced. They can only be triggered so many times though, so once they've opened and closed a few times they become inactive and basically just serve as normal leaves for photosynthesis.

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