Reding Ilona, Kelley Michael, Rowell Jonathan T, Rychtář Jan
University of North Carolina at Wilmington , Wilmington, NC, USA.
Appalachian State University , Boone, NC, USA.
R Soc Open Sci. 2016 Nov 30;3(11):160788. doi: 10.1098/rsos.160788. eCollection 2016 Nov.
Population distributions depend upon the aggregate behavioural responses of individuals to a range of environmental factors. We extend a model of ideally motivated populations to describe the local and regional consequences of interactions between three populations distinguished by their levels of cooperation and exploitation. Inspired by the classic prisoner's dilemma game, stereotypical fitness functions describe a baseline non-cooperative population whose fitness decreases with density, obligate co-operators who initially benefit from the presence of conspecifics, and kleptoparasites who require heterospecifics to extract resources from the environment. We examine these populations in multiple combinations, determine where both local and regional coexistence is permitted, and investigate conditions under which one population will invade another. When they invade co-operators in resource-rich areas, kleptoparasites initiate a dynamic instability that leads to the loss of both populations; however, selfish hosts, who can persist at low densities, are immune to this risk. Furthermore, adaptive movement may delay the onset of instability as dispersal relieves dynamic stress. Selfish and cooperative populations default to mutual exclusion, but asymmetric variations in interference strength may relax this condition and permit limited sympatry within the environment. Distinct sub-communities characterize the overall spatial structure.
种群分布取决于个体对一系列环境因素的总体行为反应。我们扩展了一个理想动机种群模型，以描述按合作和剥削水平区分的三个种群之间相互作用的局部和区域后果。受经典囚徒困境博弈的启发，典型适应度函数描述了一个基线非合作种群，其适应度随密度降低，专性合作者最初受益于同种个体的存在，以及盗窃寄生者，它们需要异种个体从环境中获取资源。我们以多种组合研究这些种群，确定在哪些地方允许局部和区域共存，并研究一个种群会入侵另一个种群的条件。当盗窃寄生者在资源丰富的地区入侵合作者时，它们会引发动态不稳定，导致两个种群都消失；然而，能够在低密度下持续存在的自私宿主对这种风险具有免疫力。此外，适应性移动可能会延迟不稳定的发生，因为扩散减轻了动态压力。自私种群和合作种群默认相互排斥，但干扰强度的不对称变化可能会放宽这一条件，并允许在环境中有限度地同域共存。不同的子群落表征了整体空间结构。
