Catchment Research Group, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom.
Environ Pollut. 2010 Feb;158(2):447-54. doi: 10.1016/j.envpol.2009.08.040. Epub 2009 Sep 25.
We combined stable isotope tracers of blood plasma, blood cells and egg contents with faecal analysis during pre-breeding and egg laying phases in two dipper species Cinclus cinclus and Cinclus mexicanus to determine the occurrence of dietary shifts during egg production and to assess consequences for egg contaminant loads. In both species, changes in delta(13)C (C. cinclus) or delta(15)N (C. mexicanus) in female plasma relative to red blood cells indicated a dietary shift during laying that was not observed in males. Eurasian dippers increased prey consumption as breeding approached, shifting from primarily trichopteran insect larvae to ephemeropterans and plecopterans. In American dippers, egg-laying females switched to feeding at a higher trophic level by consuming more fish. Eggs derived from higher trophic level diets contained more mercury (American dipper), polychlorinated biphenyls and some organochlorines, especially DDT metabolites. The results demonstrate how dietary changes during egg laying accompany the demands for egg production with consequences for contaminant deposition in avian eggs.
我们在两种河乌（Cinclus cinclus 和 Cinclus mexicanus）的繁殖前期和产卵期，将稳定同位素示踪剂（血液、血细胞和卵内容物）与粪便分析相结合，以确定在产卵期间是否发生了饮食变化，并评估这些变化对卵污染物负荷的影响。在这两个物种中，相对于红细胞，雌性血浆中 δ(13)C（C. cinclus）或 δ(15)N（C. mexicanus）的变化表明，在产卵期间存在饮食变化，但在雄性中未观察到这种变化。欧亚河乌在繁殖期临近时增加了猎物的消耗，从主要以毛翅目昆虫幼虫为食转变为蜉蝣目和蜻蜓目。在美洲河乌中，产卵的雌鸟通过更多地捕食鱼类来提高食物的营养水平。来自更高营养水平的饮食的卵中含有更多的汞（美洲河乌）、多氯联苯和一些有机氯，特别是滴滴涕代谢物。研究结果表明，产卵期间的饮食变化如何伴随着对卵生产的需求，以及这些变化对鸟类卵中污染物沉积的影响。
