Spatial Awareness of a Bacterial Swarm

TL;DR

This paper demonstrates that bacterial swarms can collectively sense environmental obstacles through independent individual responses, enabling the swarm to compute gradients without explicit communication.

Contribution

It reveals that bacterial swarms can sense obstacles by collective gradient computation using independent behaviors, without explicit inter-agent communication.

Findings

Swarming bacteria can detect inert obstacles along their path.

Independent individual responses can produce collective gradient sensing.

Swarm behavior emerges without explicit communication.

Abstract

Bacteria are perhaps the simplest living systems capable of complex behaviour involving sensing and coherent, collective behaviour an example of which is the phenomena of swarming on agar surfaces. Two fundamental questions in bacterial swarming is how the information gathered by individual members of the swarm is shared across the swarm leading to coordinated swarm behaviour and what specific advantages does membership of the swarm provide its members in learning about their environment. In this article, we show a remarkable example of the collective advantage of a bacterial swarm which enables it to sense inert obstacles along its path. Agent based computational model of swarming revealed that independent individual behaviour in response to a two-component signalling mechanism could produce such behaviour. This is striking because independent individual behaviour without any explicit communication between agents was found to be sufficient for the swarm to effectively compute the gradient of signalling molecule concentration across the swarm and respond to it.