Theory

Bacterial collectives combine signalling, division of labour, environmental memory and local decision rules to achieve capabilities unavailable to individual cells.

In part one of this series, we looked at a simple example of cellular automata in the form of the Game of Life.

Simple information constraints can push biological collectives into self-reinforcing consensus that becomes detached from the outside world. Cornell researchers modelled agents such as animals in groups and cells in tissues, relaxing two unrealistic assumptions: that individuals know the evidence behind neighbours’ decisions and can attend to every neighbour simultaneously.

Social insects provide concrete examples of collectives enforcing system-level constraints through local behaviour even when no individual can measure the state of the whole group.

Collective animals can communicate indirectly through the fluid disturbances their own movements leave behind. This extends stigmergy beyond persistent structures such as ant pheromone trails or termite construction.

A minimal flocking model shows that a directional change initiated by one agent can propagate across an entire group at approximately constant speed through asymmetric local interactions alone.

Act I Part 1: The Game with No Player The adaptive-emergent blog has over 100 posts on swarm and natural intelligence: communication even though some of these describe the most basic microbial life.

A game theory model examines how collective intelligence can arise when each individual observes only one part of a complex environment.

Kagoshima University researchers identified methyl benzoate as an airborne plant-defence signal whose release rises around dusk. Plants receiving the compound activate defence-related genes through NPR1, a central regulator of plant immunity, using a response pattern distinct from the better-known signal methyl salicylate.

To Which Quorum Should a Bacterium Listen? In the first article on microbial communication, we saw how bacteria release chemical signals that accumulate as a population grows.