Patterns of egg yolk antioxidant co-variation in an avian brood parasite-host system
Patterns of egg yolk antioxidant co-variation in an avian brood parasite-host system
复制标题
禽类寄生虫-宿主系统中蛋黄抗氧化剂共变的模式
DOI：
10.1007/s00265-010-1048-3
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发表时间：
2010
影响因子：
2.3
通讯作者：
Royle N
中科院分区：
文献类型：
--
作者：
Royle N
尽管它们对后代的健康结果很重要，但以前很少有关于禽类幼虫在其他物种的巢中产卵的母体效应的研究。在这里，我们研究了蛋黄抗氧化剂在鸟类宿主(红翼黑鸟，Agelaius pheniceus)及其孵化寄生虫(褐头牛鸟，Molothus ater)中的沉积模式。黄雀雏鸟直接与宿主黑鸟雏鸟争夺食物，尽管孵化出的蛋较小，但它们通过更强烈的乞讨和比宿主更快的生长而成功。饲料中的抗氧化剂，如类胡萝卜素和维生素E和A，沉积在蛋黄中，可以提高生长速度和减少氧化应激，因此提供了一种潜在的机制，通过这种机制，雌性牛鸟可以提高其幼鸟在寄主巢中的竞争力。然而，向蛋中提供抗氧化剂的成本很高，因此我们预测雌性牛鸟应该调整抗氧化剂的数量，以应对宿主质量的变化。我们发现，虽然被牛鸟寄生的红翼黑鸟幼鸟与未被寄生的幼鸟在抗氧化沉积模式上没有不同，但牛鸟卵中沉积的维生素E水平与牛鸟产卵的单个宿主幼鸟的维生素E水平密切匹配。这支持了一种预测，即雌性牛鸟调整其卵的抗氧化剂浓度，以增加它们的后代在它们所在的寄主巢中的可能竞争力，并可能有助于解释牛鸟在与更大的寄主幼鸟竞争中的成功。
Despite their importance to offspring fitness outcomes, there has been little previous work on egg-mediated maternal effects in avian brood parasites which lay their eggs in the nests of other species. Here, we examine patterns of egg yolk antioxidant deposition in an avian host (red-winged blackbird,Agelaius phoeniceus) and their brood parasite (brown-headed cowbird,Molothrus ater). Cowbird nestlings compete directly for food with host blackbird chicks and succeed, despite hatching from a smaller egg, by begging more intensely and growing as or more rapidly than their hosts. Dietary-derived antioxidants, such as carotenoids and vitamins E and A, deposited in egg yolk, may enhance growth rate and reduce oxidative stress, and therefore provide a potential mechanism by which female cowbirds could enhance the competitiveness of their young in host nests. However, provision of antioxidants to eggs is costly so we predicted that female cowbirds should adjust the amount of antioxidants in response to variation in host quality. We found that whilst red-winged blackbird clutches parasitised by cowbirds did not differ in the pattern of antioxidant deposition compared to non-parasitised clutches, levels of vitamin E deposited in cowbird eggs were closely matched to that of the individual host clutch in which cowbirds laid their egg. This supports the prediction that female cowbirds adjust the antioxidant concentration of their eggs to increase the likely competitiveness of their offspring in the host nest into which they are laid and may help explain the success of cowbirds in competing with larger host young.