Imagine if your first instinct during an epidemic wasn’t to wear a mask or stock up on groceries, but instead to start rearranging and remodeling your house. As it turns out, researchers have found that black garden ants (Lasius niger) do exactly that when confronted with the threat of disease. These tiny architects instinctively spring into action, redesigning their nests in various ways to slow the spread of infection and protect their crowded colonies where diseases can easily spread.
Read more about the research and see how these findings offer insights into how spatial changes – both in ants and potentially in human environments – can help limit the risks of infection.
Experimental Design: Observing Ants’ Nest Changes in Reaction to Pathogens
Recently, researchers at the University of Bristol conducted an experiment to investigate whether black garden ants modify their nest architecture in response to pathogens to reduce the risk of disease transmission.
The experiment involved 20 ant colonies, each containing 180 ants, along with 25 mg of early-instar brood and 15 pupae, placed in soil-filled containers. The ants were allowed to excavate nests freely for 24 hours, and a baseline CT scan was then taken. Then, 20 ants treated with the fungal pathogen Metarhizium brunneum were introduced into 10 colonies, while the remaining 10 colonies received ants treated with a sham solution to act as a control (1).
Over the next six days, CT scans were taken at 24, 48, 72, and 144 hours to monitor nest development and structure (1).
Key Findings: Nest Modifications
Researchers at the University of Bristol observed several critical changes in the pathogen-exposed colonies compared to the controls (1):
- Faster Nest Excavation: The pathogen-exposed colonies worked faster, showing a significant increase in the rate of tunnel formation. Note: Although nests initially grew faster after pathogen exposure, the total number of tunnels and chambers remained similar by the experiment’s end, suggesting that significant structural changes may take longer.
- Altered Surface Activity and Increased Entrance Spacing: Over time, treated and untreated ants left the nest less frequently, but pathogen-exposed ants exited at a much higher rate. Concurrently, their nests also had entrances spaced 0.62 cm (or 1 to 1.5 ant body lengths) farther apart than control nests, reducing surface contact and potentially limiting disease spread.
- Chamber Relocation: Critical chambers, like those for the queen and brood, which are usually centrally located, were moved to more isolated, less-connected areas to reduce exposure to infection.
- Topological Changes: The nest networks became less centralized, with higher modularity and increased diameter (fewer connections and longer tunnels), reducing direct transmission routes.
These modifications created physical barriers that helped reduce contact between individuals, effectively functioning as a form of ‘social distancing’ within the colony. The results showed reduced fungal loads and decreased the number of ants exposed to lethal doses of the pathogen. This is a significant discovery, marking the first known instance of nonhuman animals modifying their environment in response to an infection threat.
The Concept of “Architectural Immunity”
This nest-modifying behavior is a new layer to what scientist’s call “social immunity,” a phenomenon seen in social insects where collective behaviors protect the group from disease. In ants, social immunity typically involves grooming and self-isolation, but the discovery of “architectural immunity” shows that ants also modify their physical surroundings to limit disease spread (1).
Similar to how humans create quarantine zones or implement social distancing during epidemics or pandemics, ants instinctively adjust their nests to reduce direct interactions and transmission routes. This demonstrates how the structure of their environment becomes a tool for protecting the colony.
Wider Research Implications
This discovery sheds light not only on ant behavior but also on how changing the environment can be a powerful way to defend against disease. In human history, urban planning and architectural design have played key roles in managing disease outbreaks, such as during the bubonic plague and cholera epidemics. The ants’ ability to redesign their nests in response to pathogens could inspire new ways to think about controlling disease in human populations, particularly in densely packed environments like cities.
Studying how spatial organization can help prevent disease spread in both human and nonhuman societies offers new possibilities for improving public health strategies.
References
- Leckie, L., Andon, M. S., Bruce, K., & Stroeymeyt, N. (2024). Architectural immunity: ants alter their nest networks to prevent epidemics. bioRxiv (Cold Spring Harbor Laboratory). https://doi.org/10.1101/2024.08.30.610481
Latest posts by Shannon Sindermann (see all)
- Extreme Makeover, Epidemic Edition: Can Ants Modify Their Nests for Survival? - October 10, 2024
- Taking the Plunge: How the Seine Became Olympic-Ready - August 27, 2024
- What do Exosomes have to do with Cancer Research? - May 30, 2024
