Understanding the evolution of pathogen niche width is important for predicting disease spread and the probability that pathogens can emerge in novel hosts. Findings from previous theoretical studies often suggest that pathogens will evolve to be specialists in specific host environments. However, several of these studies make unrealistic assumptions regarding demographic stochasticity and the ability of pathogens to select their hosts. Here, an individual-based model was used to predict how population size, virulence and pathogen mutation rate affects the evolution niche specialism in pathogens. Pathogen specialism evolved regardless of virulence or populations size; thus, the findings of this study are somewhat consistent with those of previous work. However, because specialist pathogens had only a weak selective advantage over generalist pathogens, high mutation rates caused random trait variation to accumulate, preventing the evolution of specialism. Mutation rate varies greatly across different species and strains of pathogen. By showing that high mutation rates may prevent pathogen specialism evolving, this study highlights an intrinsic pathogen trait that may influence the evolution of pathogen niche width.

中文翻译：

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种群规模、突变率和毒力对病原体生态位宽度的进化影响。

了解病原体生态位宽度的演变对于预测疾病传播和病原体在新宿主中出现的可能性很重要。先前理论研究的结果通常表明病原体将进化为特定宿主环境中的专家。然而，其中一些研究对人口统计随机性和病原体选择宿主的能力做出了不切实际的假设。在这里，基于个体的模型用于预测种群规模、毒力和病原体突变率如何影响病原体的进化生态位专业性。无论毒力或种群大小如何，病原体专业都会进化；因此，这项研究的结果与以前的工作有些一致。然而，由于专科病原体比通才病原体只有微弱的选择优势，高突变率导致随机性状变异积累，从而阻止了专科的进化。突变率因病原体的不同物种和菌株而有很大差异。通过表明高突变率可能会阻止病原体特化的进化，这项研究强调了一种可能影响病原体生态位宽度进化的内在病原体特征。