Laaksonen Toni, Negro Juan J, Lyytinen Sami, Valkama Jari, Ots Indrek, Korpimäki Erkki
Section of Ecology, Department of Biology, University of Turku, Turku, Finland.
PLoS One. 2008 Jun 11;3(6):e2374. doi: 10.1371/journal.pone.0002374.
Animals use carotenoid-pigments for coloration, as antioxidants and as enhancers of the immune system. Carotenoid-dependent colours can thus signal individual quality and carotenoids have also been suggested to mediate life-history trade-offs.
To examine trade-offs in carotenoid allocation between parents and the young, or between skin coloration and plasma of the parents at different levels of brood demand, we manipulated brood sizes of Eurasian kestrels (Falco tinnunculus).
Brood size manipulation had no overall effect on plasma carotenoid levels or skin hue of parents, but female parents had twice the plasma carotenoid levels of males. Males work physically harder than females and they might thus also use more carotenoids against oxidative stress than females. Alternatively, females could be gaining back the carotenoid stores they depleted during egg-laying by eating primarily carotenoid-rich food items during the early nestling stage. Fledglings in enlarged broods had higher plasma carotenoid concentrations than those in reduced broods. This difference was not explained by diet. In light of recent evidence from other species, we suggest it might instead be due to fledglings in enlarged broods having higher testosterone levels, which in turn increased plasma carotenoid levels. The partial cross-foster design of our experiment revealed evidence for origin effects (genetic or maternal) on carotenoid levels of fledglings, but no origin-environment interaction.
These results from wild birds differ from studies in captivity, and thus offer new insights into carotenoid physiology in relation to division of parental care and demands of the brood.
动物利用类胡萝卜素色素进行着色、作为抗氧化剂以及作为免疫系统的增强剂。因此，依赖类胡萝卜素的颜色可以表明个体质量，并且也有人提出类胡萝卜素能够调节生活史中的权衡取舍。
为了研究在不同育雏需求水平下，亲代与子代之间，或者亲代皮肤颜色与血浆之间类胡萝卜素分配的权衡取舍，我们对欧亚红隼（Falco tinnunculus）的育雏规模进行了操控。
育雏规模的操控对亲代的血浆类胡萝卜素水平或皮肤色调没有总体影响，但雌性亲代的血浆类胡萝卜素水平是雄性的两倍。雄性在体力上比雌性更辛苦，因此它们可能也比雌性消耗更多的类胡萝卜素以应对氧化应激。或者，雌性可能通过在雏鸟早期阶段主要食用富含类胡萝卜素的食物来补充产卵期间消耗的类胡萝卜素储备。育雏规模扩大的雏鸟血浆类胡萝卜素浓度高于育雏规模缩小的雏鸟。这种差异无法用饮食来解释。根据其他物种的最新证据，我们认为这可能是由于育雏规模扩大的雏鸟睾酮水平较高，进而提高了血浆类胡萝卜素水平。我们实验的部分交叉寄养设计揭示了雏鸟类胡萝卜素水平存在起源效应（遗传或母体）的证据，但没有起源 - 环境相互作用。
这些来自野生鸟类的结果与圈养研究不同，从而为与亲代抚育分工和育雏需求相关的类胡萝卜素生理学提供了新的见解。
