Simulation study of bacterial colonies formed by the twitching motility: The effect of slingshot-like motions of bacteria on the colony edge

Statistical properties and patterns of bacterial colony formed by the twitching motility are studied from the viewpoint of both computer simulations and experimental examinations. Models of four kinds of bacterial motion are proposed and the growing bacterial colonies due to the models are simulated by means of Monte Carlo method. Macroscopic patterns of the bacterial colonies and orientational order parameters of the bacteria are analyzed. By comparing the simulation results with the colony pattern formed by Thermus thermophilus, we suggest that wriggling edge of the colony is caused by slingshot-like motions of bacteria.