Reproductive Strategies of South Polar Skuas: The role of food in chick survival and sibling aggression

在鸟类种群中包容性适应和亲代冲突的思想发展之前，杀婴行为一直被认为是与自然选择理论相违背的。关于同类相食、同类相食和收养外来雏鸟的情况，最近提出了几种假设，关于鸟类繁殖策略的研究通常考虑的是试图抚养雏鸟的父母所面临的权衡。这项拟议研究的目的是测试有关食物供应和父母喂养在南极罗斯岛的南极贼鸥（Catharacta maccormicki）中作为兄弟姐妹攻击导致兄弟姐妹自杀和雏鸟饥饿的原因的假设。南极贼鸥是少数几个由饥饿来调节兄弟间攻击的例子之一。食物量假说预测，在提供的巢（食物补充）中，雏鸟之间的攻击会减少，从而减少杀姐妹的情况，提高生长速度，提高繁殖成功率。鸡蛋和小鸡死亡的原因和时间也将被确定，以及贼鸥如何每年调整它们的繁殖策略。拟议的研究将致力于对硅酸盐或硅酸盐对南极贼鸥繁殖成功的重要性进行定量描述（机制）。

Until the development of the ideas of inclusive fitness and parent- offspring conflict among avian populations, infanticide has been viewed inimical to the theory of natural selection. Several hypotheses about the circumstances by which siblicide, cannibalism, and adoption of foreign chicks should occur have been suggested recently and studies on the reproductive strategies of birds commonly consider the trade-offs facing parents that are trying to raise chicks. The purpose of the proposed research will be to test hypotheses concerning the role of food availability and parental feeding as a cause of sibling aggression leading to siblicide and nestling starvation in the South Polar Skua, Catharacta maccormicki, on Ross Island, Antarctica. The South Polar Skua represents one of the few examples where sibling aggression is mediated by hunger. The Food Amount Hypothesis predicts less aggression between chicks in provisioned nest (food supplement), resulting in fewer cases of siblicide, higher growth rates, and increased reproductive success. The causes and timing of egg and chick mortality will also be determined and how skuas adjust their reproductive strategies from one year to the next. The proposed research will be devoted to developing a quantitative description (mechanism) of siblicide or the importance of siblicide to the reproductive success of the South Polar Skua.