Touching a dionea does not necessarily close its trap immediately. Under the studied conditions, a second close electrical signal can trigger the movement. The plant therefore retains for a short time an effect of the first contact, without possessing a brain.
A research published in 2020 makes it possible to follow the variations of calcium in its tissues. Each excitement is accompanied by an increase that spreads and then decreases. If a new excitement occurs quickly enough, the effects add up and exceed the threshold associated with the closure. If the first effect has decreased too much, the same result is not obtained.
To say that the dionea counts is a useful image, but it does not manipulate numbers like a person. The researchers observe an electrical and chemical mechanism sensitive to the elapsed time. The suspense of the trap thus comes from a precise condition: the next signal must arrive before the trace of the previous has been sufficiently erased.
What we know
Triggering depends on signals and threshold, not a magic rule of any two contacts.
To go to the source
References consulted on September 21, 2026. Linked pages may be in another language.
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