García-Campa Jorge, Müller Wendt, González-Braojos Sonia, García-Juárez Emilio, Morales Judith
Department of Evolutionary Ecology National Museum of Natural Sciences - Spanish National Research Council (CSIC) Madrid Spain.
Department of Biology Behavioural Ecology and Ecophysiology Group University of Antwerp Antwerp Belgium.
Ecol Evol. 2020 Apr 24;10(11):4968-4978. doi: 10.1002/ece3.6250. eCollection 2020 Jun.
During egg laying, females face a trade-off between self-maintenance and investment into current reproduction, since providing eggs with resources is energetically demanding, in particular if females lay one egg per day. However, the costs of egg laying not only relate to energetic requirements, but also depend on the availability of specific resources that are vital for egg production and embryonic development. One of these compounds are carotenoids, pigments with immuno-stimulatory properties, which are crucial during embryonic development. In this study, we explore how carotenoid availability alleviates this trade-off and facilitates egg laying in a small bird species, the blue tit (). Blue tits have among the largest clutch size of all European passerines and they usually lay one egg per day, although laying interruptions are frequent. We performed a lutein supplementation experiment and measured potential consequences for egg laying capacity and egg quality. We found that lutein-supplemented females had less laying interruptions and thus completed their clutch faster than control females. No effects of treatment were found on the onset of egg laying or clutch size. Experimentally enhanced carotenoid availability did not elevate yolk carotenoid levels or egg mass, but negatively affected eggshell thickness. Our results provide hence evidence on the limiting role of carotenoids during egg laying. However, the benefits of laying faster following lutein supplementation were counterbalanced by a lower accumulation of calcium in the eggshell. Thus, even though single components may constrain egg laying, it is the combined availability of a range of different resources which ultimately determines egg quality and thus embryonic development.
在产卵过程中，雌性面临着自我维持与当前繁殖投入之间的权衡，因为为卵子提供资源在能量上要求很高，尤其是当雌性每天产一枚卵时。然而，产卵的成本不仅与能量需求有关，还取决于对卵子生产和胚胎发育至关重要的特定资源的可用性。这些化合物之一是类胡萝卜素，一种具有免疫刺激特性的色素，在胚胎发育过程中至关重要。在这项研究中，我们探讨了类胡萝卜素的可用性如何缓解这种权衡，并促进一种小型鸟类蓝山雀的产卵。蓝山雀在所有欧洲雀形目鸟类中拥有最大的窝卵数，它们通常每天产一枚卵，尽管产卵中断很频繁。我们进行了叶黄素补充实验，并测量了对产卵能力和卵质量的潜在影响。我们发现，补充叶黄素的雌性产卵中断较少，因此比对照雌性更快地完成了它们的窝卵数。在产卵开始或窝卵数方面未发现处理的影响。实验性提高类胡萝卜素的可用性并没有提高卵黄类胡萝卜素水平或卵重，但对蛋壳厚度有负面影响。因此，我们的结果提供了类胡萝卜素在产卵过程中起限制作用的证据。然而，补充叶黄素后更快产卵的好处被蛋壳中钙的积累减少所抵消。因此，即使单一成分可能会限制产卵，但最终决定卵质量从而胚胎发育的是一系列不同资源的综合可用性。
