Greg Sword, Ph.D., studies desert locusts and other swarming insects like crickets and is a researcher in the Behavioral Plasticity Research Institute at Texas A&M University. New research provides a new, science-based theory about how these pests move as a collective. (Sam Craft/Texas A&M AgriLife)
Greg Sword, Ph.D., studies desert locusts and other swarming insects like crickets and is a researcher in the Behavioral Plasticity Research Institute at Texas A&M University. New research provides a new, science-based theory about how these pests move as a collective. (Sam Craft/Texas A&M AgriLife)
When millions of desert locusts move together across North African landscapes, consuming everything green in their path, they appear to share a single mind. For decades, scientists believed these spectacular swarms followed simple rules based on alignment with neighbors. New research using virtual reality has just turned this understanding on its head, revealing locusts as complex decision-makers rather than particles following fixed rules.
The groundbreaking study, published in the February 28 issue of Science, challenges longstanding theories about how locust swarms coordinate their movement, with implications for predicting and managing devastating outbreaks that threaten food security across multiple continents.
“It is time to move beyond the conception of locusts and other organisms as moving particles behaving according to fixed spatiotemporal rules and to consider organisms as probabilistic decision-makers responding dynamically to their sensory environment,” write authors Camille Buhl and Stephen J. Simpson in an accompanying perspective piece.
For over twenty years, scientists have relied on a model borrowed from physics—the self-propelled particle (SPP) model—to explain how locusts achieve their remarkable synchronization. This approach suggested that as density increases, locusts automatically align their movement direction with nearby neighbors within a defined interaction zone, triggering a sudden shift from chaotic movement to coordinated marching.
The research team led by Sercan Sayin solved a major technical challenge that had limited previous studies. Rather than trying to infer individual locust behavior from group observations, they created an immersive virtual environment where single locusts could move freely while surrounded by computer-generated locusts.
This “technical tour de force,” as Buhl and Simpson describe it, allowed the researchers to precisely control what each test locust saw while measuring exactly how it responded—something impossible to achieve in natural swarms where every individual influences others simultaneously.
What they discovered fundamentally changes our understanding of these ancient agricultural pests. When placed between two groups moving in the same direction, test locusts didn’t continue aligned movement as all previous models predicted. Instead, they made a decisive turn toward one group or the other, treating other locusts as targets to pursue rather than neighbors to align with.
The researchers also found no evidence for a density threshold that triggers coordinated movement—another core prediction of traditional models. Additionally, locusts didn’t respond to wide-field optical flow as some alternative theories had suggested.
The findings point toward what neuroscientists call a “ring attractor model,” where the locust’s brain continuously updates its heading based on changing visual inputs and internal neural dynamics, similar to navigation systems found in other insects.
The desert locust (Schistocerca gregaria) is perhaps nature’s most dramatic example of behavioral plasticity. When reared in isolation, these insects actively avoid each other and try to remain hidden from predators. Yet just hours of crowding triggers a remarkable transformation, causing them to seek out other locusts and form dense aggregations that eventually transform into the marching bands that farmers have feared throughout recorded history.
Understanding precisely how these swarms operate isn’t just academic curiosity. Locust outbreaks remain one of agriculture’s most persistent threats, capable of consuming crops that would feed millions of people. The 2019-2022 locust crisis in East Africa and South Asia affected over 23 million people and cost hundreds of millions in control efforts and crop losses.
The next research challenge will be testing whether this new cognitive model can successfully predict the movement patterns of actual locust bands across larger landscapes and real-world environments. Researchers will also investigate whether the model explains the specific positioning of locusts within bands, which previous studies have shown follow distinctive patterns.
As climate change potentially alters the frequency and intensity of locust outbreaks, this deeper understanding of swarm dynamics could help authorities develop more effective early intervention strategies, potentially saving millions in food resources and control costs.
This research represents the convergence of behavioral analysis, neuroscience, and virtual reality technology—tools that are finally allowing scientists to peer into the cognitive processes driving one of nature’s most mesmerizing and economically significant collective behaviors.
Did this article help you?
If you found this reporting useful, please consider supporting our work with a small donation. Your contribution lets us continue to bring you accurate, thought-provoking science and medical news that you can trust. Independent reporting takes time, effort, and resources, and your support makes it possible for us to keep exploring the stories that matter to you. Together, we can ensure that important discoveries and developments reach the people who need them most!