  In this work we give specific examples of competition models, with six and
eight species, whose three-dimensional dynamics naturally leads to the
formation of string networks with junctions, associated with regions that have
a high concentration of enemy species. We study the two- and three-dimensional
evolution of such networks, both using stochastic network and mean field theory
simulations. If the predation, reproduction and mobility probabilities do not
vary in space and time, we find that the networks attain scaling regimes with a
characteristic length roughly proportional to $t^{1/2}$, where $t$ is the
physical time, thus showing that the presence of junctions, on its own, does
not have a significant impact on their scaling properties.

Biological Physics