The population structure of social species has important consequences for both their demography and transmission of their pathogens. We develop a metapopulation model that tracks two key components of a species’ social system: average group size and number of groups within a population. While the model is general, we parameterize it to mimic the dynamics of the Yellowstone wolf population and two associated pathogens: sarcoptic mange and canine distemper. In the initial absence of disease, we show that group size is mainly determined by the birth and death rates and the rates at which groups fission to form new groups. The total number of groups is determined by rates of fission and fusion, as well as environmental resources and rates of intergroup aggression. Incorporating pathogens into the models reduces the size of the host population, predominantly by reducing the number of social groups. Average group size responds in more subtle ways: infected groups decrease in size, but uninfected groups may increase when disease reduces the number of groups and thereby reduces intraspecific aggression. Our modeling approach allows for easy calculation of prevalence at multiple scales (within group, across groups, and population level), illustrating that aggregate population-level prevalence can be misleading for group-living species. The model structure is general, can be applied to other social species, and allows for a dynamic assessment of how pathogens can affect social structure and vice versa.

社会物种的种群结构对其人口结构和病原体的传播都有重要影响。我们开发了一个元种群模型，用于跟踪物种社会系统的两个关键组成部分：平均群体规模和群体内的群体数量。虽然该模型是通用的，但我们对其进行参数化以模拟黄石狼群和两种相关病原体的动态：疥癣和犬瘟热。在最初没有疾病的情况下，我们表明群体规模主要取决于出生率和死亡率以及群体分裂形成新群体的速度。群体的总数取决于裂变和融合的速率，以及环境资源和群体间侵略的速率。将病原体纳入模型可减少宿主种群的规模，主要是通过减少社会群体的数量。平均群体规模以更微妙的方式作出反应：受感染群体的规模缩小，但当疾病减少群体数量从而减少种内攻击时，未受感染的群体可能会增加。我们的建模方法允许轻松计算多个尺度（组内、跨组和种群水平）的流行率，说明总体种群水平流行率可能会误导群居物种。该模型结构是通用的，可以应用于其他社会物种，并允许动态评估病原体如何影响社会结构，反之亦然。但是当疾病减少群体数量从而减少种内攻击时，未感染的群体可能会增加。我们的建模方法允许轻松计算多个尺度（组内、跨组和种群水平）的流行率，说明总体种群水平流行率可能会误导群居物种。该模型结构是通用的，可以应用于其他社会物种，并允许动态评估病原体如何影响社会结构，反之亦然。但是当疾病减少群体数量从而减少种内攻击时，未感染的群体可能会增加。我们的建模方法允许轻松计算多个尺度（组内、跨组和种群水平）的流行率，说明总体种群水平流行率可能会误导群居物种。该模型结构是通用的，可以应用于其他社会物种，并允许动态评估病原体如何影响社会结构，反之亦然。