Body-to-body and body-to-environment interaction emerging dynamical behavior in cell group of motile cyanobacteria

Dynamical colony pattern formation in motile cyanobacteria Pseudanabaena sp. was investigated. Collectives of the bodies are self-organized and form various motile colony patterns on agar plates. The coexistence of collective movements of four types was observed: translationally moving single strands, bundles, comet-like colonies, and a rotating disk. Additionally, the colony patterns switch to others. Existence of body-to-body and body-to-environment interactions were supposed through experimental observations and the analyses. Investigation by a self-propelled particle model revealed that both interactions are necessary for the diversity of colony morphologies and internal and/or external perturbations can trigger the switching phenomena among the colonies.