Figure 2
From: Phototaxis as a Collective Phenomenon in Cyanobacterial Colonies
Finger formation and individual cell paths at different stages. The left column displays the position of each cell, indicated by green markers, while the concentration of slime is proportional to the intensity of colour (darker implying more slime). (a) At t = 0, the cells lie within a circular colony. In the presence of a light source placed at infinity (to the right of the colony), the colony morphology gradually changes. (c) At around t = 8 × 103 finger like projections begin to form. (e) As seen from this snapshot at t = 50 × 103, smaller projections can merge over time to form larger, well-defined projections. The right column displays the path of a representative cell (purple) and those of surrounding cells (gray) over an interval of 103 steps. The thick lines represent the spatial scales of each of the panels (which is identical in both x and y directions), and their extent is denoted by the corresponding number on top. The cases shown are for (b) the initial trajectory (t = 0–103), (d) early finger formation (t = 8 × 103–9 × 103), and (f) late finger formation (t = 5 × 104–5.1 × 104).
