roundworms know how to make decisions!

“Beasts of Science” is like a collection of stories. Good stories that tell life in all its freshness. But also in all its complexity. A break to marvel at the treasures of the world. For this new episode, we will discover a fun animal, invisible to the naked eye: a round worm.

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[EN VIDÉO] Algorithms and their decision making
Increasingly, algorithms are replacing humans in decision making or task execution. They take into account a number of parameters but the question of the transparency of the algorithms arises: can they explain their decision?

If I tell you the truth, I like it earthworm, you know what animal I’m talking about. This nasty beast, with a soft, supple body. Unappetizing, but whose role is essential to our soils. Because worms dig galleries that allow them to aerate and circulate water more easily, for example. But you can imagine, all this is not voluntary. Worms are still animals, let’s say … “primitives”. And it’s hard to imagine them endowed with any form ofintelligence. Difficult? It didn’t take long for researchers to take an interest in the case of a particular worm.

the Pristionchus pacificus is one of the so-called roundworms. A nematode, to be exact. Finally as 4/5 of the animals that inhabit our Earth. It is even a free-living nematode. Therefore, he is not one of those who can interfere with us. And provoke in us some gastrointestinal disorders problematic.

However, it should be noted that the Pristionchus pacificus they may adopt behaviors that seem strange to us. At least. For example, he likes to live next to beetles. When they die, the nematode takes advantage to devour everything that will begin to swarm in its remains. Because he thanks them both bacteria that fungi.

To bite to kill or to flee, you have to choose

It is this particularity that researchers have explored. He wonders if Pristionchus pacificus is able to make informed decisions when it comes to eating. Informed options for this animal that is just over 300 neurons ? Although sometimes it’s hard for us to get there with our 86 billion nerve cells? Let me see…

The story includes a second protagonist. His name, Caenorhabditis elegans. A small worm about a millimeter long. A nematode, too, and Pristionchus pacificus it looks like a prey. At least, quite clearly, with regard to the larvae of Caenorhabditis elegans. Our round worm it kills them and devours them easily. From a bite. On the other hand, he has more difficulties with adults. For which their bites are not usually fatal.

So why Pristionchus pacificus do they persist in attacking these worms once they have reached adult size? Researchers tell us that he only does this when he has a completely different goal in mind. From bacteria which also feeds Caenorhabditis elegans. Therefore, it attacks it more to protect its territory and keep it away from a potential food source than in the hope of enjoying it.

Until then, scientists imagined it Pristionchus pacificus only biting for predation purposes. But these observations show that this little worm hid its game well, it seems able to weigh the costs and benefits of an action – the bite – implemented to achieve different goals. To finally make the best decision for him.

So, the basics of decision making Ultimately, it might be easier to codify, biologically speaking, than the researchers thought. We need to understand the extent of this codingis done in the brain, what its molecular foundations are and how flexible it can be. But in the meantime, we have to admit it Pristionchus pacificus not so stupid!

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