Junctions and spiral patterns in Rock-Paper-Scissors type models

TL;DR

This paper explores complex spiral and junction patterns in generalized Rock-Paper-Scissors models with multiple species, revealing new types of population structures and their scaling behaviors.

Contribution

It demonstrates for the first time the emergence of N-armed spiral patterns in multi-species RPS models with cyclic predation, extending previous population dynamics studies.

Findings

N-armed spiral patterns can develop for both odd and even N.

Interface networks with Y-type junctions follow a $L \,\propto\, t^{1/2}$ scaling law.

Population networks with N-armed spirals have a roughly constant characteristic length.

Abstract

We investigate the population dynamics in generalized Rock-Paper-Scissors models with an arbitrary number of species $N$. We show, for the first time, that spiral patterns with $N$-arms may develop both for odd and even $N$, in particular in models where a bidirectional predation interaction of equal strength between all species is modified to include one N-cyclic predator-prey rule. While the former case gives rise to an interface network with Y-type junctions obeying the scaling law $L \propto t^{1/2}$, where $L$ is the characteristic length of the network and $t$ is the time, the later can lead to a population network with $N$-armed spiral patterns, having a roughly constant characteristic length scale. We explicitly demonstrate the connection between interface junctions and spiral patterns in these models and compute the corresponding scaling laws. This work significantly extends the results of previous studies of population dynamics and could have profound implications for the understanding of biological complexity in systems with a large number of species.