The Devil Lies in the Details for Species Coexistence Stability in Ablated and Unablated Five-Species Evolutionary Spatial Cyclic Games

Dave Cliff

2025

Abstract

I present exploration of key results from the series of ablated five-species “Rock-Paper-Scissors-Lizard-Spock” minimal agent-based evolutionary models of biodiversity introduced by Zhong, Zhang, Li, Dai, & Yang in their 2022 paper “Species coexistence in spatial cyclic game of five species” (Chaos, Solitons and Fractals, 156: 111806). At the heart of Zhong et al.’s model of ecosystems coexistence is the Elementary Step (ES) algorithm in which one or two neighboring agents are chosen at random to engage in one or more interactions selected at random from the set {COMPETE, REPRODUCE, MOVE}. Minor revisions to the ES algorithm have recently been introduced to make it more computationally efficient in space and in time, and one contribution of this paper is to demonstrate that switching to this “Revised ES” (RES) has the unexpected effect of totally changing the outcomes of Zhong et al.’s simulation experiments. I present analysis of the RES-based experiments which shows that the key difference is that in RES the likelihood of an agent moving is decoupled from the likelihood of an agent reproducing or competing, whereas in the original ES the likelihoods of the three possible actions are interdependently coupled. The fact that such relatively minor changes to the ES algorithm result in such major changes in the experiment outcomes casts significant doubt on the extent to which results such as those from Zhong et al.’s original experiments can be trusted as truly representative of the real-world biological systems that they are supposedly intended to model. Python source-code available on GitHub can be used to replicate the results presented here.

Paper Citation

in Harvard Style

Cliff D. (2025). The Devil Lies in the Details for Species Coexistence Stability in Ablated and Unablated Five-Species Evolutionary Spatial Cyclic Games. In Proceedings of the 18th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 1: BIOINFORMATICS; ISBN 978-989-758-731-3, SciTePress, pages 545-554. DOI: 10.5220/0013132500003911

in Bibtex Style

@conference{bioinformatics25,
author={Dave Cliff},
title={The Devil Lies in the Details for Species Coexistence Stability in Ablated and Unablated Five-Species Evolutionary Spatial Cyclic Games},
booktitle={Proceedings of the 18th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 1: BIOINFORMATICS},
year={2025},
pages={545-554},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0013132500003911},
isbn={978-989-758-731-3},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 18th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 1: BIOINFORMATICS
TI - The Devil Lies in the Details for Species Coexistence Stability in Ablated and Unablated Five-Species Evolutionary Spatial Cyclic Games
SN - 978-989-758-731-3
AU - Cliff D.
PY - 2025
SP - 545
EP - 554
DO - 10.5220/0013132500003911
PB - SciTePress