Computer code for a model describing the emergence of a long transient regular spatial pattern from interaction of competing aquatic macrophytes and a biocontrol agent

A spatially explicit simulation model was developed for competition
between floating (FAV) and submersed (SAV) aquatic vegetation in which an
insect biocontrol agent (weevil) consumes FAV biomass. In all simulations,
a dynamic regular striped pattern of rock-scissors-paper (weevil-FAV-SAV)
eventually forms and persists for thousands of days despite stochastic
disturbances in the form of added adult weevils. At some point in the
simulation, depending on the random number initiator, an apparently
insignificant spatial deviation in small set of pixels triggers an
instability that grows rapidly until the striped pattern has been replaced
by a chaotic-appearing pattern. Investigation shows that the time lags
involved in the weevil life cycle and assumptions on spatial movement lead
to the instability and end of long transient.  This research
reveals the detailed mechanisms by which a long transient striped pattern
transitions to an irregular pattern, offering insights into how spatial
pattern form and change.