12-08-2025
The Intelligence of Ants. How Tiny Brains Build Great Societies
A SOCIETY WITHOUT A LEADER
URLWhen we think of complex societies, we often picture bustling cities, global communication networks, or towering institutions. But long before human civilization emerged, nature had already produced extraordinary examples of cooperation, division of labor, and collective work: ant colonies. These tiny insects, each with a minuscule brain, build remarkably sophisticated societies, caring for their young, farming, waging wars, and coordinating massive construction projects, all without a central leader.
Although an ant colony has a queen, she does not direct any activity that happens in the nest. Ant colonies are sometimes called “superorganisms” because they function as a whole made up of many interdependent parts. There is no boss-ant issuing orders; instead, complex behaviors emerge from countless small interactions, primarily through chemical signals called pheromones. This decentralized coordination allows ants to build intricate nests, respond to environmental changes, and adapt their workforce based on need, all with extraordinary efficiency.
Each ant has a role—nurse, forager, soldier, queen—and they can move between these roles depending on age, environmental conditions, and the needs of the colony. What’s remarkable is that these behavioral shifts are accompanied by profound and dynamic changes in brain chemistry, structure, and gene expression, a striking example of brain plasticity in action.
CHEMICAL BRAINS AND SOCIAL CONTEXTS
Despite having only about 250,000 neurons (compared to the human brain’s 86 billion), ants rely on many of the same neuromodulators we do—like serotonin, dopamine, and octopamine—to regulate motivation, mood, and behavior. In our lab at UNAM we study how these brain chemicals shape social behaviors, how they change with age or task, and how different ant brains are wired for different jobs.
In our research we’ve found that genes involved in making neuromodulators like dopamine and octopamine are turned on or off depending on an ant’s age and role. These chemicals help regulate behavior, whether it’s foraging, caring for the young, or guarding the nest. To understand their impact, we’re building detailed maps of the ant brain, identifying where key types of neurons—those producing dopamine, octopamine, or serotonin—are located and how they connect.
We also study a molecule called inotocin, the insect equivalent of oxytocin, which in mammals plays a role in social bonding. In ants, inotocin levels are higher in foragers than in nurses, and increasing its levels can make ants more likely to leave the nest. But the same chemical can produce different effects depending on the colony’s context. For example, increasing inotocin causes old ants to forage more when larvae are present. However, when larvae are absent and pupae present, inotocin causes young ants to forage more. This remarkable context-dependent modulation highlights how flexible and plastic ant brains are, not only in structure and gene activity, but how they are shaped by social interactions and environmental cues.
THE ROYAL PUZZLE: FERTILITY AND LONGEVITY
One of the most fascinating mysteries in ant biology is the link between reproduction and longevity. Queens live 30 to 40 times longer than workers, even though their genome is essentially the same. In most animals, fertility comes at a cost to lifespan. But ant queens, at the same time, are highly fertile and have a remarkably long life.
To understand how this happens, we study the brains and ovaries of queens and workers. One key difference we’ve found is in the insulin signaling pathway, a major regulator of aging and metabolism. In queens, this pathway is more active in the brain. These findings suggest that ant queens have evolved unique ways to bypass the typical trade-off between fertility and longevity. Such changes are yet another example of the extraordinary neuroendocrine plasticity found in these insects. Unlocking how they do this could help us to better understand aging and brain health in humans.
THIS CHALLENGES THE LONG-HELD IDEA THAT THE BRAIN LOSES PLASTICITY AT OLDER AGES
REWIRING THE BRAIN IN ADULTHOOD
To understand how flexible brains can be, we study three ant species with very different social systems. In one, roles like queen and worker are fixed for life. In another, some workers can take over the queen’s role if she dies, behaving like queens, activating their ovaries and living longer. A third species is made up of clones that naturally switch between queen-like and worker-like behaviors.
By comparing these species, we are uncovering the genes and pathways that allow adult ants to change their behavior, physiology, and even brain function. These discoveries shed light on how brains adapt to changing life circumstances.
We believe that our findings in ants offer a powerful example of how flexible the adult brain can be. In some species, individuals can dramatically reshape their brains and bodies in response to changes in their social environment, long after development is complete. This challenges the long-held idea that the brain loses plasticity at older ages. By studying these remarkable transformations in ants, we hope to shed light on the biological mechanisms that support brain plasticity, knowledge that could eventually inform research on learning, recovery, and aging in the human brain.
Studying ants isn’t just about understanding insects. It’s about grasping the fundamental principles of social behavior, cooperation, and adaptability that govern all kinds of life. Ants show us that intelligence doesn’t always require size or centralized control. It can emerge from interaction; between neurons, between individuals, and between the brain and the environment.
In my lab at UNAM’s Institute of Biomedical Research, we believe these tiny animals hold giant keys to understanding ourselves, not only how we think and age, but how we live and work together. By using ants as novel model systems, our research uncovers fundamental principles of brain plasticity, social behavior, and longevity that are often inaccessible in traditional models. This work, rooted in basic science, has been supported by both international and national organizations, including the Global Consortium for Reproductive Longevity and Equality (GCRLE) at the Buck Institute, and UNAM’s PAPIIT program. Our findings highlight the power of comparative approaches in biology and how even the smallest creatures can transform how we understand life itself.
STUDYING ANTS ISN’T JUST ABOUT UNDERSTANDING INSECTS, BUT GRASPING THE FUNDAMENTAL PRINCIPLES OF SOCIAL BEHAVIOR
From Emergent Systems to Artificial Intelligence
UNAM Internacional
A couple of decades ago, the American science writer Steven Johnson published Emergence, a book that explored areas in which it was possible to see changes taking place towards a kind of functional systematicity without central command, without intention, or apparent direction. From the nascent realm of complexity sciences and based on the example of the mud or mucilaginous mold, a kind of protist (very simple living beings that do not fall within the classification of fungus, plant, or animal) whose independent cells are capable of uniting and organizing themselves into a kind of larger organism, the author described four types of self-organizing systems.
The first was that of ant colonies which, as doctor Fetter explains in this article, are capable of developing complex structures of behavior and construction without having a centralized direction (although Johnson did not have at hand the intervention of chemical compounds in the modification of ant behaviors, which makes these processes somewhat less “casual” or automatic).
Then he considered the human brain: neuroscientific research at the beginning of the 21st century already showed situations of neuronal self-organization in what would later be understood as neuronal networks and in the processes of transmission of information through them: the surprise was to find out how these systems learn.
He then addressed cities, which, at least before modern urbanism was developed, reached states of organization without apparent planning, without manifest objectives, without development program. Today we know that the absence of urban planning generates chaos; it is not practical to leave to self-organization the solution of problems generated by uncontrolled growth and development; applying the lines of research of complexity sciences to the urban environment was a simplification.
Finally, and this seemed to be the objective of his analyses, Johnson turned his attention to software, where some of the first manifestations of the new internet or “Web 2.0” began to operate, in which many processes started developing unforeseen results, apparently also self emerging. This was the case of the SimCity game series and Amazon’s recommendations system, which by aggregating huge amounts of customer reviews began to make accurate suggestions for new customers.
25 years later, the large linguistic processing models on which the systems we know as artificial intelligence are based, and the algorithms with which they operate, take full advantage of these “natural” capacities of information to offer us accurate answers to complex questions without the intervention of a central will behind them. The similarities of these systems with the functioning of our brain as described by neurosciences are not a coincidence, but the result of an intense interdisciplinary dialogue that links the basics of the chemical and the biological with cybernetics and the processing of big data.
Ficha: Emerging systems or What Ants, Neurons, Cities and Software. New York: Scribner, 2002.
Ingrid Fetter-Pruneda holds a bachelor’s degree in Biology from the Faculty of Sciences at UNAM and a Ph.D. in Science from the same university. She completed a postdoctoral fellowship at The Rockefeller University in New York before joining as a principal investigator at the Department of Cell Biology and Physiology of UNAM’s Institute of Biomedical Research. Her work focuses on understanding the molecular, cellular, and neurobiological mechanisms regulating social behavior and phenotypic plasticity in social insects, particularly ants.
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