How do ants carrying food to the nest overcome obstacles on the way?
From building the pyramids to moving the refrigerator in the kitchen - the ability of humans to cooperate in carrying a heavy load is a rare ability in nature. In fact, as far as is known, the only animals that exhibit a similar ability are ants. It's not for nothing that ants have fascinated humans for thousands of years: the sight of a group of tiny ants in miraculous coordination carrying a worm or cockroach many times larger than them is one of the wonders of nature. But what happens when the ants encounter an obstacle on their way to the nest, and are required, in the language of the popular navigation software, to recalculate a route? A new study by Weizmann Institute of Science scientistsRecently published in the scientific journal PLoS Computational Biology, showed how, with the help of very simple rules of conduct, the ants can switch randomly between two courses of action, and thus overcome the obstacles in their way.
As anyone who has ever moved knows very well, it is difficult to transport objects without coordination between the carriers. If so, how do the ants communicate, and how do they divide the work between them? In a previous study by the group of Prof. Nir Gov, from the Department of Chemical and Biological Physics, and the Ant Laboratory of Dr Ofer Finerman, from the Department of Physics of Complex Systems, discovered that communication is mechanical. "When an ant approaches a food item, it feels the forces exerted by the other ants carrying it, and accordingly decides whether it should pull the item or pick it up," explains Prof. Gov. "If she feels that the load is moving away from her, that is, she is at the back, she lifts, and if the load is moving toward her, that is, she is in front of it, she pulls. This summarizes the decision-making of the individual ant, and enables efficient movement in the group."
This is how the ants behave when their movement is free. But what happens when they discover that the nice loot they found doesn't easily slip through the cracks and crevices where ants that don't carry cargo can easily pass? In the current study, led by research student Yoni Ron from Prof. Gov's lab, the researchers built a mathematical model that tracks the behavior of ants when they encounter an impassable barrier with a narrow opening. The simulations predicted that the ants would randomly switch between two courses of action: they would crowd near the opening in an attempt to pass through, or they would oscillate left and right in an attempt to find a way around the obstacle. Prof. Gov explains: "The same simple rules, according to which each ant decides whether to pull or lift the load according to the forces it feels, are also valid in this model. There is no ant here or several ants saying to themselves: 'Wait, we have reached the checkpoint, what do we do now?' ' None of them understand that there is a barrier; they just do what they know best, just like in free movement. In other words, the problem is 'solved' through the collective without any ant being required to solve the problem individually."
According to the model, the size of the group of ants, which reflects the size of the food item, will determine which course of action will be dominant: small groups carrying small pieces of food will spend more time near the narrow opening, thus increasing the chance of pushing the piece of food through the opening, while large groups More will move more to the sides, thus increasing their chances of bypassing the obstacle.
The researchers tested the predictions of the model through experiments on ants (see videos) that carried loads of different sizes. When the ants encountered an impassable barrier with a narrow opening, they did switch randomly between the two predicted courses of action. Also, smaller groups, carrying smaller items, spent more time near the opening. "It was impossible to squeeze our object through the narrow passage, but even it the ants managed to turn on its side, and almost thread it through the hole. In reality, a worm or an insect is of course much more flexible," says Prof. Gov.
>> Video 1: The ants crowd near the opening trying to get through
>> Video 2: The ants oscillate left and right trying to get around the obstacle
In the future, the research team plans to investigate the movement of food-carrying ants in more complex conditions, with obstacles of different sizes and shapes, in a way that better simulates the natural conditions in the field. Dr. Itay Pinkovetsky, while he was a research student in Prof. Gov's lab, and staff scientist Dr. Ehud Ponio from Dr. Finerman's ant lab also participated in the current study.
>> Video 3: Embarking on a new path: the ants manage to bypass the obstacle
10 ants - this is the optimal group size for carrying a food item. The larger the group, the more "conformist" the ants will be, and the efficiency of their movement will suffer. And what is the optimal size for making decisions in a group of people?
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You reminded me that every board of a company should have an odd number of members and 3 is too much!
sounds interesting
Where can you see the model?
Thanks
Excellent article. In the field of mathematical theories for biological systems - you starred in Hidan.
Yehuda
I think that many species actually have no leader. In many flocks of birds there is no leader (starlings for example), and in flocks that have a "leader" (like geese) - this is a temporary role and the whole idea there is to save energy. There is no leader in schools of fish either. Bees have a "queen" but she is a slave, not exactly a leader.
The ants see that there is no leader - take the ants out of the convoy, and the convoy continues as if nothing had happened.
In engineering there are many systems that work in combination of many agents without a leader. drone bands and certain software for example.
Leadership requires qualities that will separate the leader from other creatures: unique knowledge, strength, size or body structure. You also need communication between the leader and the rest. These are things you don't see in ants.
Yehuda,
I don't think you're right, it makes more sense that they behave like a flock of birds. There is always one bird at the head of the flock that leads the birds flying behind it, but any one of them can replace it at any moment. That is, all the birds in the flock are equal and there is no one permanent leader that is her role.
It is easy to conduct an experiment that will test your claim, we will take a large group of ants and each time we will randomly select 30 ants from it and give them the task of transporting a piece of food to the nest through an obstacle.
If after several such experiments it does not seem that there is a difference in the technique of transferring the food, we can conclude that there is no leader ant in the group, but rather there is cooperation between ants who are equal in their role.
How safe is it that there is no leader among the ants? After all, all productions have a leader, so why would it be missing from the ants? It is necessary to notice how a change is made in the movement of the ants. Something directed it and he is the leader.
Good night
Yehuda
How confident are you that there are no leadership ants here that direct the movement? After all, in all productions there is a leader, a figure who takes the initiative, for example birds, wild herds, and possibly bees. And there are certainly more examples,
Good night
Yehuda
It reminds me of a séance board, the participants place their fingers on the glass and suddenly it starts to move 🙂
https://www.youtube.com/watch?v=l6J5rCzqy_A
Ants also cut food details to pass it through a narrow opening.