This carnivorous plant has a clever system to catch insects instead of other things

There are more than 600 species of carnivorous plants but the Venus flytrap (Dionaea muscipula) is the most iconic. This plant traps insects in its jaws to make up for the few nutrients it takes in from its soil.

The plant naturally does not have eyes to know if what it is trying to eat is an insect or not: it could be a piece of leaf, or some other piece of debris. So how do you ensure that the prey is nutritionally interesting?

As explained in this study, when an insect visits the trap and tilts the mechanosensors on the interior surface, action potentials (AP) are triggered.

After a moving object stimulates two different points, the trap closes and cages the victim. Prey, trying to break free, repeatedly touch the sensor hairs and, over the next few hours, through the endocrine based system the airtight trap is flooded with a cocktail of acidic enzymes that break down the prey.

In order to know that the caged object is potential food and that resources must be invested activating the glands to break it down, the plant takes into account how many times the sensor hairs are stimulated.

By applying a series of stimulations to the sensory hairs, the cited study found that the jasmonic acid (JA) touch hormone signaling pathway is activated after the second stimulus, while more than three APs are required to trigger a response. expression of genes encoding hydrolases that degrade prey, and that this expression is proportional to the number of mechanical stimulations.

That is to say, that the closure of the mechanism is activated when the dam touches hairs twice in a period not exceeding about 30 seconds. The trap then closes in a matter of milliseconds.

A decomposing animal contains a charge of sodium, and these sodium ions enter the capture organ through the glands. There is a DmHKT1 flytrap sodium channel responsible for this sodium acquisition, and the number of expressed transcripts depends on the number of mechanoelectrical stimulations. Therefore, the amount of AP that a victim activates when attempting to escape the trap identifies the moving prey as a Na+-rich animal struggling to escape, as well as highly nutritious food for the plant.

More recently, another study conducted by the University of Zurich in Switzerland has found that a single slow touch also causes the trap to close. Specifically, by slowly touching a sensor hair just once, both signals can also be generated and thus lead to the closure of the trap.

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