Ants help to understand cooperation in nature – 10/05/2023 – Fundamental Science

Science estimates the existence of 20 quadrillion ants on the planet – that means 20 billion distributed in more than 15 thousand named species and subspecies. These insects are crucial to nature and play different roles in almost every ecosystem on the globe. It was the versatility of these small beings and their striking presence in biological interactions that sparked the interest of ecologist Laura Leal.

It is from these animals that the professor at the Federal University of São Paulo investigates mutualisms, an ecological relationship of cooperation between individuals of different species. A classic example is that of the bee and the flower – the first feeds on nectar or pollen and, in return, pollinates the second, without one causing harm to the other.

But in science things are not usually so simple. If the literature says that in these relationships no one is harmed, the reality appears to be less simplistic. “There are several contexts that can unbalance these partnerships. A better definition would be ‘mutual exploitation’, in which some gain more, others less and some even harm themselves through the interaction”, explains Leal.

And ants are precisely your main tool for understanding these discrepancies. Taking into account the relationship between these insects and plants, the ecologist investigates these variations and in which contexts mutualism can actually mutually benefit individuals and in which one can overexploit the other.

According to the literature, ants almost always make a profit. Mathematical models show that these insects exploit plants and can often receive more than they give in this exchange of favors. But perhaps, in practice, this is not quite the case. According to the ecologist, there is still much to be studied. “There is not enough empirical evidence to prove these models. It is a human presumption that plants, because they are immobile, are incapable of manipulating ants, but there are studies that show the opposite,” she says.

Leal works at the interface between what theory says and what reality shows. His work consists of collecting observational and experimental data to feed and reformulate current theoretical models.

“Science is not about being right, but about being less wrong,” she argues. And she points out that improving the understanding of phenomena does not mean that they are solved. “Inconsistencies will always be there, whether due to limited resources, time and space for research, or due to researchers’ biases. Our mission is to elucidate what is still poorly explained.”

Its two main models are seed dispersal – the plant offers food to the ants and they, in turn, spread the seeds throughout the environment – ​​and anti-herbivory protection interaction – the ants gain shelter or food from the plants, while the defend against herbivores, such as caterpillars.

“In this second model system, it is possible that plants offer low-quality food to partner ants while being well protected, or ants can feed on what is offered by the plant, while not defending it efficiently. Asymmetries can be many.”

The scientist’s routine consists of making observations in nature, from which she creates quantitative descriptions of phenomena as a way of understanding them and thinking about possible causes. She then conducts experiments that simulate or manipulate different situations for comparative purposes.

For example: if the presence of ants on the plant is more significant in the morning, does this mean that the nectar it offers to the ants during this period is of better quality? Based on this observation, Leal and his team manipulate the quality of the nectar at different times to better understand the animals’ behavior.

The researcher has already been to different biomes, but her heart is in arid environments. Biologist from the Federal University of Pernambuco and with a post-doctorate in zoology from the State University of Feira de Santana, in Bahia, Leal worked for many years in the caatinga. After moving to São Paulo, she became enchanted by the cerrado.

“In arid environments, many plants have their seeds dispersed exclusively by ants. There is a species of disperser ant measuring around 3 cm that can carry seeds up to 30 meters. It is an ecological interaction that I am especially passionate about”, he says.

Leal’s interest in these animals is not only emotional, but also practical. Ants are widely distributed and play an important role in several ecosystems. “They monopolize the underground world, perform a series of services that we have no idea about and connect various components of a system. Working with them means having many open doors, as the questions are infinite. As biologist Edward O. Wilson said, they It’s ‘the little things that rule the world’.”

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Pedro Lira is a journalist at the Serrapilheira Institute.

The Fundamental Science blog is edited by Serrapilheira, a private, non-profit institute that promotes science in Brazil. Sign up for the Serrapilheira newsletter to keep up to date with news from the institute and the blog.

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