Regulatory mechanisms and cost of reproduction

是什么阻止了动物，包括人类，产生尽可能多的最高质量的后代？进化生物学提供了一个答案，那就是繁殖是有成本的，在当前的繁殖回合中，增加投资的好处被当前条件、未来的繁殖力和存活率方面的成本所抵消。在鸟类中，来自对鸡蛋生产的投资被实验操纵的研究的大量证据支持这一概念。然而，有一个知识领域我们仍然只有一个非常初级的了解，那就是关于生殖成本背后的因果机制(S)。在历史上，人们一直认为繁殖的成本依赖于能量或营养，它涉及一种相对简单的资源分配机制，即生殖所需的资源被重新分配给其他生理功能(例如免疫功能)，而这些功能反过来又会产生负面影响。最近，有人提出，生殖成本可能是由生殖本身或生殖基础的调节(生理)机制造成的。这个项目将研究与此相关的两个观点：a)与产蛋相关的贫血会降低女性的有氧或运动能力，b)生殖会增加对氧化应激(细胞损伤)的敏感性，这与性和死亡有关。我们的方法是实验性的，整合了进化生物学、生态学和生理学。例如，我们将使用药物来增加或降低蛋鸡的贫血水平，然后直接测试对飞行性能、繁殖成功和后代生长的影响。该项目将提供有关生殖成本背后的因果机制的新颖、全面的数据。此外，尽管通过应用生理学方法，这项工作可能看起来晦涩难懂，但我们的工作将为环境变化(气候变化)对鸟类种群(例如地中海蓝山雀种群和北极筑巢的羽毛鸭)的影响，包括保护和管理关注的物种(例如大理石斑纹山雀)的关键问题提供新的见解。

What prevents animals, including humans, from producing as many offspring of the highest quality as they like? Evolutionary biology provides the answer that there is a 'cost' to reproduction wherein the benefits of increased investment in a current reproductive bout are offset by costs in terms of current condition, future fecundity and survival. In birds, considerable evidence from studies where investment in egg production has been experimentally-manipulated supports this concept. However, one area of knowledge where we still have only a very rudimentary understanding is with regard to the causal mechanism(s) underlying costs of reproduction. Historically, it has been assumed that the cost of reproduction is energy or nutrient-dependent and that it involves a relatively simple resource-allocation mechanism where resources required for reproduction are reallocated away from other physiological functions (e.g. immune function) which in turn have negative effects. More recently it has been suggested that costs of reproduction might instead be caused by reproduction itself or the regulatory (physiological) mechanisms underlying reproduction. This project will investigate two ideas related to this: a) that anemia associated with egg production decreases the aerobic or exercise performance of females, and b) that reproduction increases susceptibility to oxidative stress ("cellular damage") and that this links sex and death. Our approach is experimental and integrates evolutionary biology, ecology and physiology. For example, we will use drugs to increase or decrease the level of anemia in laying birds and then directly test effects on flight performance, breeding success, and offspring growth. This project will provide novel, comprehensive data on causal mechanisms underlying costs of reproduction. Furthermore, although this work might seem esoteric through the application of physiological approaches our work will provide novel insight into key questions concerning effects of environmental variation (climate change) on avian populations (e.g. Mediterranean blue tit populations and Arctic-nesting eider ducks), including species of conservation and management concern (e.g. marbled murrelets).