Modeling Cost-Associated Cooperation: A Dilemma of Species Interaction Unveiling New Aspects of Fear Effect

TL;DR

This paper presents a new mathematical model exploring how partial cooperation among species affects ecosystem stability, revealing an optimal cooperation level and the protective role of fear in preventing collapse.

Contribution

It introduces a novel Lotka-Volterra-based model for cost-associated partial cooperation and demonstrates how fear of predation can stabilize ecosystems under certain conditions.

Findings

Partial cooperation benefits ecosystems up to an optimal intensity.

Beyond this point, costs lead to system collapse via heteroclinic bifurcation.

Fear of predation can prevent regime shifts even with high cooperation levels.

Abstract

With limited resources, competition is widespread, yet cooperation persists across taxa, from microorganisms to large mammals. Recent observations reveal contingent factors often drive cooperative interactions, with the intensity heterogeneously distributed within species. While cooperation has beneficial outcomes, it may also incur significant costs, largely depending on species density. This creates a dilemma that is pivotal in shaping sustainable cooperation strategies. Understanding how cooperation intensity governs the cost-benefit balance, and whether an optimal strategy exists for species survival, is a fundamental question in ecological research, and the focus of this study. We develop a novel mathematical model within the Lotka-Volterra framework to explore the dynamics of cost-associated partial cooperation, which remains relatively unexplored in ODE model-based studies. Our findings demonstrate that partial cooperation benefits ecosystems up to a certain intensity, beyond which costs become dominant, leading to system collapse via heteroclinic bifurcation. This outcome captures the cost-cooperation dilemma, providing insights for adopting sustainable strategies and resource management for species survival. We propose a novel mathematical approach to detect and track heteroclinic orbits in predator-prey systems. Moreover, we show that introducing fear of predation can protect the regime shift, even with a type-I functional response, challenging traditional ecological views. Although fear is known to resolve the "paradox of enrichment," our results suggest that certain levels of partial cooperation can reestablish this dynamic even at higher fear intensity. Finally, we validate the system's dynamical robustness across functional responses through structural sensitivity analysis.