Data from: Mortality risk and social network position in resident killer whales: sex differences and the importance of resource abundance

An individual’s ecological environment affects their mortality risk, which in turn has fundamental consequences for life history evolution. In many species social relationships are likely to be an important component of an individual’s environment, and therefore their mortality risk. Here we examine the relationship between social position and mortality risk in resident killer whales (Orcinus orca) using over three decades of social and demographic data. We find that the social position of male, but not female, killer whales in their social unit predicts their mortality risk. More socially integrated males have a significantly lower risk of mortality than socially peripheral males, particularly in years of low prey abundance, suggesting that social position mediates access to resources. Male killer whales are larger and require more resources than females, increasing their vulnerability to starvation in years of low salmon abundance. More socially integrated males are likely to have better access to social information and food sharing opportunities which may enhance their survival in years of low salmon. Our results show that observable variation in the social environment is linked to variation in mortality risk, and highlight how sex differences in social effects on survival may be linked to sex differences in life-history evolution.个体所处的生态环境会影响其死亡风险，而死亡风险反过来又对生活史演化产生根本性影响。在诸多物种中，社会关系往往是个体所处环境乃至其死亡风险的重要构成要素。本研究依托超过三十年的社会行为与种群统计数据，探究了居留型虎鲸（Orcinus orca）的社会地位与死亡风险之间的关联。研究发现，在其社会群体中，雄性虎鲸的社会地位能够预测其死亡风险，而雌性虎鲸则无此显著关联。社会融入程度更高的雄性虎鲸，其死亡风险显著低于处于社会边缘的雄性个体，这一效应在猎物丰度较低的年份尤为突出，表明社会地位可调控个体获取资源的途径。雄性虎鲸体型较雌性更大，所需资源也更多，这使得它们在鲑鱼丰度低迷的年份更易遭受饥饿胁迫。社会融入度更高的雄性虎鲸，往往能更便捷地获取社会信息与食物共享机会，这或许能提升它们在鲑鱼匮乏年份的存活率。本研究结果表明，社会环境中可观测到的变异与死亡风险的变异存在显著关联，同时也揭示了社会因素对存活率影响的性别差异，该差异可能与生活史演化的性别差异存在内在联系。