Capital Expenditure, Lactation Energetics and the Importance of Foraging to Weddell Seals and their Pups

资本支出、哺乳能量以及觅食对威德尔海豹及其幼崽的重要性

• 批准号: 0538592
• 负责人: Olav Oftedal
• 金额: --
• 依托单位: Smithsonian Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2010-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0538592&HistoricalAwards=false
• 关键词: Capital; Expenditure; Lactation; Energetics; Importance

Animals that employ 'capital breeding' rely principally on stored reserves to support reproduction. Many species of Phocid seals appear to rely on a combination of stored reserves and ongoing foraging to support lactation costs. The Weddell seal (Leptonychotes weddellii) of Antarctica had been thought to fast during its relatively long lactation (6-8 weeks), but evidence from feeding biomarkers, diving behavior and maternal mass loss suggests that most females feed, at least in late lactation. Feeding is predicted to be especially important in smaller females with limited body stores of substrates and energy. The proposed research will investigate capital expenditure, lactation energetics and the importance of food intake in the Weddell seal using a novel multimarker approach to determine: (1) Changes in maternal capital stores over the course of lactation; (2) Maternal energy expenditure; (3) Maternal milk production including transfer of energy, fat, water and protein to pups; (4) Timing of the onset of feeding in lactating females and pups; (5) Contribution of food intake to the maternal energy and substrate budget; and (6) Duration of the lactation period and nature of the weaning process. By labeling maternal and offspring body water pools with two distinct isotopes of hydrogen, we can measure water turnover, changes in body composition, and milk transfer to pups, even if pups begin to forage. Onset of feeding by mothers and pups will be assessed from circulating levels of dietary biomarkers and will be compared to diving activity obtained from time depth-recorders and radiotransmitters. The quantitative importance of food energy intake to lactating seals will be determined by a comparison of summed energy expenditures to energy mobilization form stores in animals known to be fasting or feeding. Detailed estimates of energy and protein budgets of mother-pup pairs will be developed. Prey samples will be analyzed for analysis of gross composition, biomarker and energy content, and key hormones and metabolites in lactating Weddell seals will be monitored. From these data, the relative importance of capital expenditure and food intake, and of energy vs. protein, in the evolution of a mixed capital and income breeding strategy will be evaluated. To achieve broader impact for this work, a dynamic, multi-level outreach package, typical of the Smithsonian National Zoological Park's award-winning science outreach program, will be developed. This package will include exhibits located at the National Zoo that involve a range of techniques such as computer-based multi-media and video presentations, interactive exhibits, demonstrations and one-on-one interpretive interactions between scientists and zoo visitors. A web page about the project will be added to the National Zoo's extraordinarily popular web site. Scientists involved in the project will meet quarterly with youths from the Columbia Science Workshop, an NSF-funded science program for under-served minority youths located in the Zoo's neighboring community and run by the Zoo's science outreach staff.

采用“资本繁殖”的动物主要依靠储备来支持繁殖。 许多种类的Phocid海豹似乎依赖于储存储备和持续觅食的组合来支持哺乳成本。南极洲的威德尔海豹（Leptonychotes weddellii）被认为在其相对较长的哺乳期（6-8周）禁食，但来自摄食生物标志物，潜水行为和母体质量损失的证据表明，大多数雌性海豹至少在哺乳后期进食。喂养预计是特别重要的，在较小的女性有限的身体存储的底物和能量。 这项研究将调查资本支出，哺乳能量学和食物摄入的重要性，在威德尔海豹使用一种新的多标记方法，以确定：（1）在哺乳过程中母亲的资本储备的变化;（2）母亲的能量消耗;（3）母亲的牛奶生产，包括转移的能量，脂肪，水和蛋白质的幼崽;（4）哺乳期雌性和幼崽开始进食的时间;（5）食物摄入对母体能量和底物预算的贡献;（6）哺乳期的持续时间和断奶过程的性质。通过用两种不同的氢同位素标记母体和后代的身体水池，我们可以测量水的周转，身体成分的变化，以及乳转移到幼崽，即使幼崽开始觅食。母鼠和幼鼠开始进食的时间将根据食物生物标志物的循环水平进行评估，并与从时间深度记录仪和无线电发射机获得的潜水活动进行比较。通过比较已知禁食或进食动物的总能量消耗与能量动员形式储存，确定食物能量摄入对哺乳期海豹的定量重要性。将对母鼠和幼鼠的能量和蛋白质预算进行详细估计。 将对猎物样本进行分析，以分析总成分、生物标志物和能量含量，并监测哺乳期威德尔海豹的关键激素和代谢物。从这些数据中，资本支出和食物摄入量的相对重要性，能量与蛋白质，在一个混合的资本和收入的育种策略的演变将进行评估。为了实现这项工作的更广泛的影响，一个动态的，多层次的外展包，典型的史密森国家动物园的获奖科学外展计划，将开发。这套展品将包括位于国家动物园的展品，涉及一系列技术，如基于计算机的多媒体和视频演示、互动展品、演示以及科学家和动物园游客之间的一对一解释性互动。一个关于这个项目的网页将被添加到国家动物园非常受欢迎的网站上。参与该项目的科学家将每季度与来自哥伦比亚科学研讨会的年轻人会面，这是一个由NSF资助的科学项目，面向位于动物园附近社区的服务不足的少数民族青年，由动物园的科学推广人员负责。