Extinction in four species cyclic competition

TL;DR

This study investigates extinction dynamics in four-species cyclic competition, revealing how neutral partnerships and spatial structure influence the time to dominance and the persistence of large domains.

Contribution

It provides a detailed numerical analysis of extinction routes and the impact of neutral partner swapping on the longevity of species domains.

Findings

Long-lived states with large mixed domains dominate when swapping is allowed.

Extinction pathways are diverse and depend on spatial structure and neutral partner interactions.

Averaged measures like mean domination time miss many extinction scenarios.

Abstract

When four species compete stochastically in a cyclic way, the formation of two teams of mutually neutral partners is observed. In this paper we study through numerical simulations the extinction processes that can take place in this system both in the well mixed case as well as on different types of lattices. The different routes to extinction are revealed by the probability distribution of the domination time, i.e. the time needed for one team to fully occupy the system. If swapping is allowed between neutral partners, then the probability distribution is dominated by very long-lived states where a few very large domains persist, each domain being occupied by a mix of individuals from species that form one of the teams. Many aspects of the possible extinction scenarios are lost when only considering averaged quantities as for example the mean domination time.