Using stable isotopes to quantitatively track endogenous and exogenous nutrient allocations to eggs of birds that travel to breed
Using stable isotopes to quantitatively track endogenous and exogenous nutrient allocations to eggs of birds that travel to breed
复制标题
使用稳定同位素定量跟踪繁殖鸟类蛋的内源和外源营养分配
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
K. Hobson
中科院分区：
文献类型：
--
作者：
K. Hobson
测量鸟类繁殖中内源性营养分配的传统方法依赖于种群中几个个体的抽样，以对比蛋窝的质量增加与产卵雌性组织的质量损失。其理由是，雌性在产卵期间内源性组织的大量损失可归因于对繁殖的“资本”投资。除了这项工作的破坏性外，与这种方法有关的问题还包括内在储备和卵子之间的转换效率不确定，以及关于个别策略的信息普遍丢失。因此，在大多数情况下，内生储备的作用可能被高估了。在当地（繁殖季节）饮食与通常在越冬或到达繁殖前的集结地获得的内源储备同位素不同的情况下，内源储备和卵成分的稳定同位素测量可以帮助定量地追踪内源储备与外源储备对卵的相对分配。幸运的是，一些鸟类在迁徙繁殖时改变了“同位素”，因此可以对它们的身体营养物质进行同位素追踪。例如，在沿海海洋生物群落越冬并前往陆地或淡水生物群落的鸟类，其当地食物网中几种元素（C、N、H、O和S）的同位素普遍耗尽。先前的圈养研究使我们能够估计草食性和肉食性“收入”种鸡饲粮和几种鸡蛋成分（无脂蛋黄、蛋白、蛋黄脂质、壳碳酸盐）之间的同位素（δ 13c和δ 15n）分馏因子。目前，我们正在使用食肉动物模型来估计内源性储备和卵子之间的预期比例。这项工作的最终结果是一个同位素多源混合模型，用于预测内源性与外源性蛋白质和脂质资本对鸡蛋的相对分配。虽然该模型还需要进一步完善，但它为未来涉及营养分配的鸟类同位素跟踪研究提供了坚实的基础。
Conventional approaches to measuring endogenous nutrient allocations to reproduction in birds have relied on the sampling of several individuals within populations in order to contrast mass gains of the clutch with mass loss of the laying female's tissues. The reasoning has been that mass loss of female endogenous tissues during laying can be attributed to 'capital' investment into reproduction. Apart from the destructive nature of this work, problems associated with this approach involve uncertain conversion efficiencies between endogenous reserves and eggs and the general loss of information on individual strategies. As a result, the role of endogenous reserves have likely been overestimated in most cases. Stable isotope measurements of endogenous reserves and egg components can help to trace quantitatively the relative allocation of endogenous vs. exogenous reserves to eggs in cases where local (breeding season) diets differ isotopically from endogenous reserves typically acquired on the wintering or staging grounds prior to arrival to breed. Fortunately several avian species change 'isoscapes' when travelling to breed and so are amenable to isotopic tracking of their body nutrients to eggs. For example, birds wintering in coastal marine biomes and travelling to terrestrial or freshwater biomes experience a general depletion in the isotopes of several elements (C, N, H, O and S) in their local foodwebs. Previous captive studies have allowed us to estimate the isotopic (δ 13 C and δ 15 N) fractionation factors between diet and several egg components (lipid-free yolk, albumen, yolk lipid, shell carbonate) for herbivorous and carnivorous 'income' breeders. Currently, we are using the carnivore model to also estimate fractionation expected between endogenous reserves and eggs. The net result of this work has been an isotopic multi-source mixing model to predict the relative allocation of endogenous vs. exogenous protein and lipid capital to eggs. While refinement is needed for this model, it provides a firm basis for future avian isotopic tracking studies involving nutrient allocations.