Robust chemotaxis beyond sensing limits: signal, noise, and strategy

TL;DR

This paper argues that bacterial chemotaxis remains effective despite low information use, due to movement strategies that confer robustness to noise, challenging traditional sensing limit views.

Contribution

It introduces a framework showing how chemotactic robustness arises from movement strategies, not just information transmission, using simple models and scaling arguments.

Findings

Chemotaxis can be robust to noise through symmetry and temporal averaging.

Low information efficiency does not necessarily mean poor chemotactic performance.

Different sensing strategies in bacteria and eukaryotes influence behavior beyond physical sensing limits.

Abstract

Bacterial chemotaxis has long been viewed as operating near the physical limits of sensing, as originally articulated by Berg and Purcell. Recent information-theoretic analyses challenge this view, suggesting that Escherichia coli uses only a small fraction of the information available in ligand arrival statistics to bias its motion. How should such low information efficiency be interpreted at the level of behavior? Here, I argue that chemotactic performance is shaped not only by information transmission and noise, but by the strategy of movement itself. Using simple scaling arguments and minimal models, I show how run-and-tumble chemotaxis can remain robust to noise through symmetry and temporal averaging, even when internal information processing is inefficient. Comparing bacterial and eukaryotic chemotaxis highlights how different sensing strategies convert physical limits into observable behavior. These considerations suggest that low information efficiency need not imply poor performance, but may instead reflect an evolved balance between robustness, simplicity, and function.