PDF(Pubmed)
Abstract：
The benefits of social living are well established, but sociality also comes with costs, including infectious disease risk. This cost-benefit ratio of sociality is expected to change across individuals\' lifespans, which may drive changes in social behaviour with age. To explore this idea, we combine data from a group-living primate for which social ageing has been described with epidemiological models to show that having lower social connectedness when older can protect against the costs of a hypothetical, directly transmitted endemic pathogen. Assuming no age differences in epidemiological characteristics (susceptibility to, severity, and duration of infection), older individuals suffered lower infection costs, which was explained largely because they were less connected in their social networks than younger individuals. This benefit of \'social ageing\' depended on epidemiological characteristics and was greatest when infection severity increased with age. When infection duration increased with age, social ageing was beneficial only when pathogen transmissibility was low. Older individuals benefited most from having a lower frequency of interactions (strength) and network embeddedness (closeness) and benefited less from having fewer social partners (degree). Our study provides a first examination of the epidemiology of social ageing, demonstrating the potential for pathogens to influence evolutionary dynamics of social ageing in natural populations.
摘要：
社会生活的好处已经确立，但是社会性也伴随着成本，包括传染病风险。这种社会性的成本效益比预计会在个人寿命范围内发生变化，这可能会随着年龄的增长推动社会行为的变化。为了探索这个想法，我们将来自一个群体生活的灵长类动物的数据与流行病学模型相结合，这些灵长类动物的社会老龄化已经被描述为表明，当年龄较大时，具有较低的社会连通性可以防止假设的成本，直接传播的地方性病原体。假设流行病学特征没有年龄差异(易感性，严重程度,和感染持续时间)，老年人感染费用较低，这在很大程度上是因为他们在社交网络中的联系比年轻人少。“社会老龄化”的这种好处取决于流行病学特征，当感染严重程度随年龄增长而增加时，这种好处最大。当感染持续时间随年龄增加时，只有当病原体传播能力较低时，社会老龄化才是有益的。老年人受益于较低的互动频率（强度）和网络嵌入性（紧密程度），而受益于较少的社交伙伴（程度）。我们的研究对社会老龄化的流行病学进行了首次检查，证明病原体可能影响自然人群中社会老龄化的进化动态。
