Social ageing: Toward a deeper understanding of the intersection between social relationships and senescence

Ageing affects many phenotypic traits, but the declines in social behaviour that occur with age have only recently become apparent. Given the well-established fitness benefits associated with social connectedness, understanding why this ‘social ageing’ occurs will be important for integrating sociality into our understanding of the ageing process. Here, I will present a framework for disentangling the drivers of social ageing and will use 8-years of behavioural data from a population of free-ranging rhesus macaques on Cayo Santiago to demonstrate evidence for one of these drivers - age-based social selectivity. I will discuss how age-based changes in social behaviour can feed up to influence an individual’s indirect connectedness in their network and overall patterns of network structure. Finally, by simulating pathogen spread through these social networks, I will explore whether social selectivity has the potential to provide benefits to older individuals by protecting against disease risk in later-life. Together, this talk will aim to demonstrate that social ageing may be an important and underappreciated aspect of an organism’s phenotype that could contribute to inter-individual variation in demographic senescence.