These ants are pure chaos, but they could save your morning coffee

In a Puerto Rican coffee farm, the researchers discovered a surprising network of chaos among ants and a predatory fly.

Three ants species Rivorize in changing cycles of domination, but when a fly targets the strongest species, balance returns in an unpredictable way. These oscillations create wild oscillations where any species can go up to the top.

Understanding the ecology of agriculture without pesticides

To reduce or even eliminate the use of pesticides, researchers at the University of Michigan highlight the importance of understanding the functioning of ecological systems in agricultural land.

John Vandermeer and Ivette Perfecto of UM applied two ecological theories to explain the complex relationships between three species of ants and a newly introduced fly which attacks one of them. In a Coffee farm in Puerto Rico, they discovered that ants and the predator fly what scientists call chaotic models – chaos in the classic sense, where natural populations increase and decrease according to the changing interactions of different system organisms.

This instability means that one of the four species of insects involved could become dominant at different times. If farmers can anticipate which ants will take the lead, they could use them as managers of natural pests. The study, supported by the National Science Foundation, appears in the Proceedings of the National Academy of Sciences.

Predict the domination of ants is delicate

“Two of the three ants of ants that we have studied are really important agents of biological control of two of important pests in coffee,” said Vandermeer, professor of ecology and evolutionary biology of Vandermeer. “We would like, or a farmer would like to be able to predict when the ants are there, and when they are not there. And it turns out that this kind of prediction will be quite difficult. ”

For more than thirty years, Vandermeer and Perfecto, professor at the UM school for the environment and sustainability, have studied how ants have interacts in the ecosystem of the farm. Their long -term objective is to reshape agricultural practices, but they argue that this is only possible once the ecological rules governing these systems are included.

“We believe that the current international agricultural system with its use of pesticides and chemicals does not contribute to the well-being of anyone, especially farmers, and actually contributes to global climate change,” said Vandermeer. “We consider that to integrate the rules of ecology into the development of new forms of agriculture, we must understand what these rules are and how these rules work.”

Ants as key pest controllers under the tropics

Under the tropics, the ants are dominant, known as Vandermeer, and often involved in agriculture as control agents for pests. But the use of a kind of ant to control pests can be complicated: the domination of the ant used as biological control depends on what other ants of ants – as well as other types of insects – are in the system.

In this system, Vandermeer and Perfecto examined two types of ecological behavior: cyclical behavior of the intransitive loop and coexistence mediated by predators. The cyclic behavior of the intransitive loop means that if there are a group of three ant, ant could be dominant on the ant B, the ant B could dominate the ant, but the ant could dominate the ant.

Predator Fly shakes the system

When a predator is thrown into the mixture, these dynamics become even more complicated. Among the three ants of ants that Vandermeer and Perfecto study, a species is dominant. But the recently introduced fly attacks the dominant ant. This predator-crop relationship affects not only the dominant ant, but it also has downstream effects on the other two ants of ants, allowing one of the four species to become the dominant species at different times. This is an example of coexistence mediated by predators.

The wax and the decline of the predator’s fly and its anti -ant target, as well as the change of domination in ants of ants, are called oscillations. By riding and modeling these two oscillating ecological principles, researchers could examine how the principles introduce chaos into the system.

Chaos cartography

The results are… chaotic. But by tracing these two oscillating behaviors, the researchers could see that at certain times, the whole system looked like a predator-root cycle, and at other times, the system looked like an intransitive loop oscillation.

This could mean – in theory – Researchers could make a window at the moment when each kind of insects was going to be the dominant species.

Complications in the application of ecology to agriculture

“The good news is that the chaotic models of insects are really very interesting of an intellectual meaning inherent. The bad news is that it is not really as simple as it might seem to base agricultural practices on ecological principles because the ecological principles themselves are much more complicated than to find a poison that kills pests,” said Vandermeer.

“What we discover, we think, in the past 30 years approximately, are some of those complications that come out if you are serious about ecology in the fundamental operations of the agricultural system.”

Reference: “Keystone Predator and Keystone Intransitivity and the Rescue of A Competitive Subdominant Species” by John Vandermeer and Ivette Perfecto, August 11, 2025, Proceedings of the National Academy of Sciences.
DOI: 10.1073 / PNAS.2421005122

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