Behavioral determinants and consequences of the natural spread of a sexuallytransmitted disease in wild olive baboons (Papio anubis)

性传播疾病(STD)是影响哺乳动物免疫系统进化的主要生态力量，并可能对交配系统的进化产生影响。尽管性传播疾病在种群中的传播在很大程度上取决于物种的交配行为，即交配伴侣的数量和每个伴侣的交配数量，但动物，如非人类灵长类动物是否已制定出应对STD风险增加或获得性传播的适应性对策，在很大程度上仍不清楚。这样的应对策略可能涉及卫生行为，如交配后生殖器或尿液的自我清洁，改变配偶选择，偏爱未感染的交配伙伴，这可能会导致迁徙到未感染群体的情况下。在我们的项目中，我们将调查坦桑尼亚曼亚拉湖国家公园(LMNP)的橄榄狒狒(Papio Anubis)种群。橄榄狒狒生活在相对较大的社会群体中，原则上表现出混杂的交配行为。LMNP种群感染梅毒螺旋体细菌，这种细菌会在人类中引起几种疾病(如梅毒)，在狒狒中会导致雄性和雌性生殖器严重、非常明显的溃疡。这些溃疡表明这些人被感染了。梅毒螺旋体很可能是通过性接触传播的。为了测试交配选择和交配后的行为是否会因为潜在交配伙伴感染的明显迹象而改变，我们将定量分析交配行为(例如交配伙伴的数量、性接触的数量)、性交后的自我打扮和交配后的小便与各自交配伙伴的健康状况的关系。作为可能影响配偶选择和交配策略的辅助因素，我们将包括优势等级、年龄(男性和女性)以及雌性也包括生殖状态。这些数据将被用来构建一个交配网络，代表STD传播的潜在途径。在一个模拟模型中，结合了网络和STD避免行为以及狒狒人口统计数据，我们将从LMNP的狒狒种群调查中收集这些数据，并从文献中获得额外的一般狒狒生活史数据，我们将能够评估长期的疾病动态。利用模拟模型的输出，我们将在观察到的狒狒种群中识别超级传播者的关键社会和人口特征，值得注意的是，该模型最终可以用来预测要治疗的最小狒狒数量，以便将种群数量控制在流行阈值以下。

Sexually transmitted diseases (STDs) represent a major ecological force in shaping the evolution of mammalian immune defences and additionally might have an impact on the evolution of mating systems. Whereas the spread of STDs in a population largely depends on the mating behaviour of a species, i.e. the number of mating partners and the number of matings per partner, it remains largely unknown whether animals, such as nonhuman primates have developed adaptive counterstrategies in response to increased STD-risk or acquisition. Such counterstrategies can involve hygienic behaviours, such as post-copulatory self-cleaning of genitals or urination, change in mate choice with a preference for non-infected mating partners, which might, in case of gregarious primates lead even to a migration into noninfected groups.In our project we will investigate a population of olive baboons (Papio anubis) at Lake Manyara National Park (LMNP) in Tanzania. Olive baboons live in relatively large social groups and show, in principle, a promiscuous mating behaviour. The LMNP-population is infected by the bacterium Treponema pallidum which causes several diseases in humans (e.g. syphilis) and in baboons massive, highly conspicuous genital ulcerations in males and females. These ulcerations signal that such individuals are infected. Most likely T. pallidum is transmitted by sexual contacts. To test whether mate choice and post-copulatory behaviour are altered by visible sign of infection in potential mating partners, we will quantitatively analyse mating behaviour (e.g. number of mating partner, number of sexual contacts), postcoital self-grooming, post-copulatory urination in relation to the health status of the respective mating partner. As possible co-factors influencing mate choice and mating strategies, we will include dominance rank, age (males and females) and in females also reproductive state. The data will be used to construct a mating network that represents potential routes for STD spread. In a simulation model, which incorporates network and STD avoidance behaviour and baboon demographic data, which we will gather from baboon population surveys in LMNP and additional general baboon life history data from the literature, we will be able to assess longterm disease dynamics. Using outputs from simulation model we will identify key social and demographic characteristics of superspreaders in the observed baboon population, and notably, this model could ultimately be used to predict the minimum number of baboons to treat in order to bring the population below epidemic threshold.