  A variety of living and non-living systems exhibit collective motion. From
swarm robotics to bacterial swarms, and tissue wound healing to human crowds,
examples of collective motion are highly diverse but all of them share the
common necessary ingredient of moving and interacting agents. While collective
motion has been extensively studied in non-proliferating systems, how the
proliferation of constituent agents affects their collective behavior is not
well understood. Here, we focus on growing active agents as a model for cells
and study how the interplay between noise in their direction of movement and
proliferation determines the overall spatial pattern of collective motion. In
this agent-based model, motile cells possess the ability to adhere to each
other through cell-cell adhesion, grow in size and divide. Cell-cell
interactions influence not only the direction of cell movement but also cell
growth through a force-dependent mechanical feedback process. We show that
noise in the direction of a cell's motion has striking effects on the emergent
spatial distribution of cell collectives and proliferation. While higher noise
strength leads to a random spatial distribution of cells, we also observe
increased cell proliferation. On the other hand, low noise strength leads to a
ring-like spatial distribution of cell collectives together with lower
proliferation. Our findings provide insight into how noise in the direction of
cell motion determines the local spatial organization of cells with consequent
mechanical feedback on cell division impacting cell proliferation due to the
formation of cell clusters.
