Scientists have long known that ant colonies sometimes seem to move as one. A nest that appears quiet can suddenly erupt into activity, with workers throughout the colony springing into motion almost simultaneously before settling back into stillness.
These synchronized bursts, first documented more than three decades ago, have intrigued biologists because they resemble collective phenomena seen in systems as diverse as neurons, fireflies and even chemical reactions.
Now, new research from engineers and biologists at New York University and the New Jersey Institute of Technology offers a mathematical explanation for how these rhythmic waves of activity emerge.
The study, published in Physical Review X Life , suggests that synchronized bursts arise when a colony balances two competing forces: the ability of a single active ant to rapidly excite its nestmates and the colony’s capacity to fully return to rest before the next wave begins.
Using a computational model grounded in empirical observations of ant behavior, the researchers found that colonies undergo a kind of phase transition — a sudden shift from unsynchronized movement to coordinated collective activity.
“Activity bursts emerge as a balance between the responsiveness of the colony to the first ant that activates and the ability of the colony to completely deactivate before the onset of the next burst,” said lead author Michael Napoli, a doctoral researcher in the Department of Mechanical and Aerospace Engineering at NYU.
The team combined decades of observations of ant movement with established theories of social activation. In the model, ants can occupy one of three states: active, inactive or refractory — a temporary resting period during which they cannot immediately become active again. Active ants move through a virtual nest and interact with others, sometimes triggering them to become active as well.
What emerged from the simulations was a surprisingly powerful role for individual workers. Rather than requiring many ants to coordinate simultaneously, a single ant often acted as the spark that ignited a colony-wide cascade of activity.
The researchers call this worker the “first mover.” Once activated, that ant can stimulate others, which in turn activate additional nestmates, creating a rapid chain reaction that sweeps through the colony. The process resembles a line of falling dominoes or the spread of information through a social network.
“Our results indicate that activity bursts in ant colonies are the result of a first mover that excites the colony in a synchronized regime, thereby favoring the rapid communication of new behaviors throughout the group,” the authors write.
The study also revealed that speed matters. Ants appear to operate in what the researchers describe as a “high-speed interaction regime,” where information spreads through the nest far more quickly than the duration of an activity burst itself. Under these conditions, workers constantly form and break social connections as they move, allowing information to travel efficiently across the colony.
According to senior author Maurizio Porfiri , the findings suggest that synchronized behavior depends not simply on how many interactions occur, but on how rapidly information can propagate through the network of moving individuals.
“The timescale of the motion of individuals through the nest is faster than that of the burst, suggesting that ants operate in a high-speed interaction regime where new behaviors are near-instantaneously transferred through the nest,” Porfiri said.
Although the study focuses on ants, its implications extend beyond insect societies. Simon Garnier , Professor of Biological Sciences at NJIT and coauthor on the paper, suggests similar leader-driven cascades appear in many complex systems, from grazing sheep that suddenly cluster together to neurons firing in coordinated patterns. By identifying the conditions that promote synchronization, the researchers hope to uncover general principles that govern collective behavior across biology.
The work could even inspire new approaches to engineering. Swarms of robots, for example, often rely on local interactions rather than centralized control. Understanding how a single agent can trigger coordinated action across a large population could help designers create more efficient systems for tasks such as warehouse logistics, environmental monitoring or disaster response.
The authors caution that their model simplifies many aspects of real ant colonies, including differences among workers and the complex spatial organization of nests. Future experiments will test whether real colonies operate near the synchronization threshold predicted by the model and whether manipulating density or movement patterns can alter the emergence of activity bursts.
For now, the research offers a compelling explanation for one of social insects’ most mysterious behaviors. What appears to be a colony acting with a single mind may actually begin with one ant taking the first step — and thousands of others rapidly following its lead.
This research was supported by a grant from the National Science Foundation .
PRX Life
Computational simulation/modeling
Not applicable
Nest-Level Phase Transition Drives Synchronized Activity Bursts in Ant Colonies
5-Aug-2026