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Updated: Jun 10, 2026
07:40
Monitoring Spatial Segregation in Surface Colonizing Microbial Populations
Published on: October 29, 2016
Collective motion and density fluctuations in bacterial colonies
H P Zhang1, Avraham Be'er, E-L Florin
1Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin, Austin, TX 78712, USA. zhang@chaos.utexas.edu
Summary
Bacteria exhibit collective motion, forming dynamic clusters and showing giant number fluctuations. This research highlights Bacillus subtilis as a model for studying biological collective behavior.
Area of Science:
- Microbiology
- Biophysics
- Complex Systems
Background:
- Collective motion is observed in various biological systems, including disease spread.
- Previous models lacked detailed experimental validation due to data limitations.
Purpose of the Study:
- To investigate collective motion in Bacillus subtilis at the individual level.
- To analyze emergent behaviors like dynamic clustering and fluctuations in bacterial populations.
Main Methods:
- Simultaneous tracking of position, velocity, and orientation for up to 1000 wild-type Bacillus subtilis.
- Analysis of bacterial colony dynamics at varying densities.
Main Results:
- Bacteria spontaneously form dynamic, closely packed clusters with cooperative movement.
- Cluster size distribution follows a power-law with an exponential tail.
- Observed "giant number fluctuations" in bacterial density, exceeding thermal equilibrium expectations.
Conclusions:
- Bacillus subtilis serves as an effective model organism for studying collective motion.
- Demonstrated giant number fluctuations in a biological system for the first time.
- Provides a foundation for understanding emergent behaviors in microbial communities.
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