Some plants have a strategy to prevent violent ant fights

Rainforests thrive on delicate relationships. Plants, animals, and insects like ants constantly interact, creating a web of survival and competition. Amid this chaos, unexpected harmony sometimes blooms.

In the tropical rainforests of Fiji, scientists uncovered a fascinating story of peacekeeping. It is not a tale of advanced creatures or complex brains. Instead, it centers around a plant with an unusual design.

This plant has developed a surprisingly simple strategy to solve conflict among aggressive ants.

This discovery from Durham University reshapes our understanding of cooperation in nature. It shows how something as basic as plant architecture can manage aggression and encourage mutual support.

The study reveals that, sometimes, structure itself can shape behavior and nurture harmony among rivals.

Ants and plants team up

The plant at the center of this story belongs to the genus Squamellaria. It is part of the Rubiaceae family, also known as the coffee family. These plants grow on the branches and trunks of rainforest trees.

The plants form large, bulbous structures called domatia. These domatia are not just growths – they serve as homes for ants. In return for shelter, ants provide the plant with essential nutrients from their waste.

However, the ants that live in these plants are not naturally friendly neighbors. Many of them are highly aggressive and often engage in violent fights with other species.

This raises an important question: how can so many aggressive species coexist peacefully inside a single plant?

Walls keep rivals apart

The answer lies in the design of Squamellaria’s domatia. Professor Guillaume Chomicki of Durham University led an international team to investigate the mystery.

Using high-resolution 3D CT scans, the researchers explored the inner structure of the plant’s domatia. What they found was remarkable. The plant creates domatia with multiple chambers, each completely sealed off from the others inside.

Every chamber has its own entrance, but inside, walls separate them from their neighbors. This design prevents physical contact between ant species. It is as if the plant built a miniature apartment complex, with each species living in its own secure unit.

This clever separation prevents fights and keeps the peace within the plant. It is not a chemical trick or behavioral adaptation by the ants. The plant’s architecture itself enforces harmony.

One plant, many ants

To test the effectiveness of this system, the researchers conducted extensive fieldwork. They observed Squamellaria plants on three Fijian islands for over a decade.

The team’s observations revealed that a single Squamellaria plant could house as many as five different ant species simultaneously. Despite their natural tendency to fight, the ants coexisted peacefully.

The researchers also performed nutrient labeling experiments using nitrogen isotopes. These experiments confirmed that all of the ant species provided valuable nutrients to the plant.

Each ant colony contributed to the plant’s well-being, making the relationship mutually beneficial for all involved.

When peace breaks down

To truly understand the importance of separation, the researchers conducted a bold experiment. They surgically removed the internal walls between the chambers of the domatia.

The results were immediate and violent. Ant species that had previously lived peacefully erupted into fierce battles. These fights led to many ant deaths on both sides.

In contrast, plants with intact chambers saw no such conflict. Even outside the plant, ants shared food sources without issue. This highlights the importance of physical separation inside the plant.

“It is incredible how such an odd group of organisms, restricted to a couple of Fijian islands, can provide general insights into the stability of cooperation between species,” noted Professor Chomicki.

A plant that solves conflicts

The team also created mathematical models to further explore the plant’s strategy. The models confirmed that compartmentalization helps maintain long-term partnerships.

The system prevents fights during the early stages of colony establishment. This allows each chamber to develop into a stable, nutrient-contributing colony.

Even in situations where only a small fraction of arriving ants were aggressive, the models showed that compartmentalized domatia performed better than single-chambered ones.

This shows that separating rivals is not just a short-term solution. It has lasting benefits for both the plant and its ant residents. The architecture ensures that mutualism remains stable over time, providing security and resources for all involved.

Hidden harmony in nature

This discovery helps solve a long-standing mystery in ecology. Scientists have wondered how unrelated and sometimes hostile species manage to maintain cooperation.

The findings suggest that physical separation could be a widely used strategy in nature. Many organisms may rely on similar methods to prevent conflict and maintain beneficial relationships.

The study of Squamellaria shows that architecture alone can shape ecosystems. It highlights the hidden power of structural design in keeping peace among species that would otherwise be at odds.

In the rainforests of Fiji, a simple plant demonstrates that sometimes, the best way to manage conflict is to keep your neighbors at a safe distance.

The study is published in the journal Science.

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