Exploring eco-evolutionary dynamics through large-scale virtual experiments with situated agents
Imagine a world where evolution unfolds not over millennia, but in hours. Where researchers can track every genetic change across generations of thousands of creatures, and where the boundaries of environment and behavior can be manipulated with the click of a mouse.
A revolutionary approach to understanding how complex behaviors emerge in ecosystems through computational simulations.
Computational organisms that live, compete, reproduce, and evolve in simulated environments with neural network policies.
Individual agents in large-scale virtual worlds 1
Grid cells in the largest experimental environments 1
Transparency in tracking evolutionary changes 5
"These digital evolution systems instantiate evolution itself, with populations of digital organisms whose neural network policies change through mutation and selection."
The continuous feedback loop between ecological interactions and evolutionary change, where each influences the other across spatial and temporal scales 5 .
Research systems that strike a balance between complexity and control, enabling observation of evolutionary processes at computer processing speeds 5 .
Digital organisms that are "situated" in environments they can both perceive and change through their actions, creating authentic ecological dynamics 1 .
Unlike population-level models that track trait frequencies, individual-based systems create unique digital organisms with their own "genetic" instructions. These organisms must navigate their environment, gather resources, avoid threats, and reproduce—with successful traits naturally persisting in the population 5 .
A groundbreaking series of experiments conducted in 2025 illustrates the power of this approach. Researchers created what they termed "Ecological Games"—massive grid-world environments where digital agents with evolving neural network policies compete for survival 1 .
Researchers built grid environments of varying sizes, with the largest reaching 1,000,000 grid cells. The environments included different terrain types, resource distributions, and physical constraints 1 .
Each agent was equipped with a neural network policy and sensory capabilities. Some agents had compass sensors for navigation, while others had vision sensors to detect resources and other agents at a distance 1 .
The digital organisms had no predefined objectives or reward signals. Instead, they needed to collect resources to survive and reproduce. When reproduction occurred, parents passed their neural network policies to offspring with random mutations 1 .
The researchers ran identical experimental conditions at different population sizes and environmental scales to directly test how physical and demographic scale affects evolutionary outcomes 1 .
A key manipulation in these experiments involved varying the sensory capabilities of the agents. This allowed researchers to test how different ways of perceiving the environment would shape the evolution of behavior.
Agents with more sophisticated sensors could potentially evolve more complex behaviors, but at the cost of more complex neural architectures that required more resources to develop and maintain 1 .
The results were striking. In small environments, populations generally evolved simple foraging strategies. But as environmental scale and population size increased, researchers observed the emergence of sophisticated behaviors never seen in smaller setups 1 .
| Behavior Type | Small Scale | Large Scale | Description |
|---|---|---|---|
| Resource Gathering | Simple local consumption | Long-range extraction expeditions | Agents evolved movement patterns specifically for distant resource collection |
| Foraging Efficiency | Basic consumption | Vision-based strategic foraging | Agents with vision sensors developed more efficient searching patterns |
| Predation | Rare or absent | Consistent evolution of predatory behavior | Some agents began specializing in consuming other agents |
| Behavioral Stability | Fluctuating strategies | Stable behavioral ecosystems | Complex communities with multiple stable behavioral niches |
Agents equipped with different sensor types evolved distinct survival strategies. Vision-equipped agents consistently outcompeted those with only basic sensors in complex environments, developing better foraging and attacking behaviors 1 .
| Sensor Type | Evolved Behaviors | Environmental Conditions | Competitive Advantage |
|---|---|---|---|
| Compass Only | Basic navigation, limited resource gathering | All environments | Moderate in simple environments |
| Vision Capabilities | Advanced foraging, predation, strategic movement | Complex environments only | High in complex environments |
| Combined Sensors | Most diverse behavioral repertoire | All environments | Highest across environments |
The experiments also provided insights into the concept of eco-evolutionary experience (EEE)—the idea that native species are more strongly impacted by non-native species the more these differ from species they have coevolved with 7 .
In the digital environments, agents encountering completely novel types of competitors often went extinct, while those facing slight variations of familiar competitors typically adapted successfully.
This digital evidence aligns with findings from biological systems, where native species with high EEE relative to invaders (meaning the invaders are similar to what they've encountered before) typically adapt more successfully 7 .
Creating and studying digital evolution requires specialized computational tools and frameworks:
| Tool Component | Function | Examples |
|---|---|---|
| Large-scale Simulators | Provides environment for evolution | JAX-based simulation environments 1 |
| Agent Architectures | Neural network policies that evolve | Evolvable neural networks with sensor inputs 1 |
| Evolutionary Mechanisms | Handles reproduction and mutation | Genetic algorithms, mutation operators 1 5 |
| Tracking Systems | Monitors populations and behaviors | Genome logging, behavior classification 1 |
| Analysis Frameworks | Quantifies eco-evolutionary dynamics | EEE classification, innovation assessment 7 |
One critical insight from recent work is that the infrastructure must be optimized for large-scale experimentation. As one research team noted, their JAX-based environment allowed them to "conduct experiments in large-scale worlds that reach populations of more than 60,000 individual agents" 1 .
This scalability isn't just a technical achievement—it's a scientific necessity, since many interesting behaviors only emerge at large scales.
Digital evolution represents more than just a new research method—it's a fundamental shift in how we study life's complexity. By creating complete evolutionary worlds where every variable can be controlled and every interaction tracked, scientists are beginning to unravel the deep connections between ecological context and evolutionary change.
This work presents "not only as a method to learn about ecology, but as an exploration of how ecology itself learns."
These virtual ecosystems have already demonstrated that scale itself plays a crucial role in evolutionary innovation—a finding with profound implications for both conservation biology and our understanding of life's history on Earth.
Predicting how real ecosystems will respond to human-caused environmental changes.
Revealing fundamental principles governing all evolving systems, whether made of carbon or code.
The most exciting prospect is that we've only begun to glimpse what's possible. As computing power continues to grow and algorithms become more sophisticated, these digital worlds may become increasingly rich, potentially even helping us understand the fundamental principles that guide evolution everywhere it occurs—in nature, in society, and perhaps even beyond Earth's biosphere.