In multipredator and multipathogen systems, exploiters interact indirectly via shared victim species. Interspecific prey competition and the degree of predator specialization are known to influence whether predators have competitive (i.e., (−,−)) or noncompetitive (i.e., (−,+) or (+,+)) indirect interactions. Much less is known about the population-level indirect interactions between pathogens that infect the same populations of host species. In this study, we use two-predator-two-prey and two-host-two-pathogen models to compare the indirect effects between predators with the indirect effects between pathogens. We focus on how the indirect interactions between pathogens are affected by the competitive abilities of susceptible and infected hosts, whether the pathogens are specialists or generalists, and the transmission pathway (direct vs. environmental transmission). In many cases, indirect effects between pathogens and predators follow similar patterns, for example, more positive indirect effects with increased interspecific competition between victim species. However, the indirect effects between pathogens can qualitatively differ, for example, more negative indirect effects with increased interspecific host competition. These contrasting patterns show that an important mechanistic difference between predatory and parasitic interactions (specifically, whether interactions are immediately lethal) can have important population-level effects on the indirect interactions between exploiters.

中文翻译：

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比较捕食者与被捕食者系统中剥削者之间的间接影响

在多捕食者和多病原体系统中，开发者通过共享的受害物种间接进行交互。种间猎物竞争和捕食者专业化程度已知会影响捕食者是否具有竞争性（即（-，-））或非竞争性（即（-，+）或（+，+））间接相互作用。对于感染相同宿主物种种群的病原体之间的种群水平间接相互作用知之甚少。在这项研究中，我们使用两个捕食者，两个猎物和两个宿主，两个病原体模型来比较捕食者之间的间接影响与病原体之间的间接影响。我们专注于病原体之间的间接相互作用如何受到易感和感染宿主的竞争能力的影响，无论病原体是专家还是通才，以及传播途径（直接还是间接）。环境传播）。在许多情况下，病原体和捕食者之间的间接作用遵循相似的模式，例如，随着受害物种之间种间竞争的加剧，更积极的间接作用。但是，病原体之间的间接影响可能在质量上有所不同，例如，随着种间宿主竞争的加剧，负面影响更大。这些相反的模式表明，掠夺性和寄生性相互作用之间的重要机制差异（特别是相互作用是否立即致命）可能对开发者之间的间接相互作用具有重要的种群级影响。受害物种之间种间竞争的加剧会带来更积极的间接影响。但是，病原体之间的间接影响可能在质量上有所不同，例如，随着种间宿主竞争的加剧，负面影响更大。这些相反的模式表明，掠夺性和寄生性相互作用之间的重要机制差异（具体而言，相互作用是否立即致命）可能对开发者之间的间接相互作用产生重要的种群级影响。受害物种之间种间竞争的加剧会带来更积极的间接影响。但是，病原体之间的间接影响可能在质量上有所不同，例如，随着种间宿主竞争的加剧，负面影响更大。这些相反的模式表明，掠夺性和寄生性相互作用之间的重要机制差异（具体而言，相互作用是否立即致命）可能对开发者之间的间接相互作用产生重要的种群级影响。