Carotenoid-Dependent Signals and the Evolution of Plasma Carotenoid Levels in Birds
Carotenoid-Dependent Signals and the Evolution of Plasma Carotenoid Levels in Birds
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DOI：
10.1086/678402
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发表时间：
2014-12-01
影响因子：
2.9
通讯作者：
Verhulst, Simon
中科院分区：
文献类型：
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作者：
Simons, Mirre J. P.;Maia, Rafael;Verhulst, Simon
性选择导致了在择偶时使用了各种各样的装饰品，这些指标性状在承担成本时诚实地表明了质量，从而防止了欺骗。类胡萝卜素依赖性显色在这方面引起了相当大的关注，因为类胡萝卜素对显色的投入必须与其生理功能进行权衡。类胡萝卜素是抗氧化剂，可以增强免疫能力。假设这种权衡是类胡萝卜素依赖性着色的诚实性的基础，表明将类胡萝卜素从体细胞维持分配到性展示的障碍。利用适应性进化建模方面的最新进展，我们采用比较方法，利用 178 种鸟类的物种水平系统发育来研究血浆类胡萝卜素水平的进化。我们发现，在进化出类胡萝卜素依赖性着色的谱系中，类胡萝卜素水平的进化最佳水平更高，并且对这种最佳水平具有强烈的吸引力。因此，考虑到较高的类胡萝卜素水平很容易响应于类胡萝卜素依赖性着色的进化而进化，类胡萝卜素似乎并不具有限制性。这些发现挑战了类胡萝卜素是稀缺资源的假设，因此也挑战了类胡萝卜素的生理资源价值是类胡萝卜素依赖性性状诚实性基础的假设。因此，比较证据表明其他因素（例如类胡萝卜素的获取和掺入）与维持信号诚实有关。
Sexual selection has resulted in a wide array of ornaments used in mate choice, and such indicator traits signal quality honestly when they bear costs, precluding cheating. Carotenoid-dependent coloration has attracted considerable attention in this context, because investing carotenoids in coloration has to be traded off against its physiological functions; carotenoids are antioxidants and increase immunocompetence. This trade-off is hypothesized to underlie the honesty of carotenoid-dependent coloration, signaling the handicap of allocating carotenoids away from somatic maintenance toward sexual display. Utilizing recent advances in modeling adaptive evolution, we used a comparative approach to investigate the evolution of plasma carotenoid levels using a species-level phylogeny of 178 bird species. We find that the evolutionary optimum for carotenoid levels is higher in lineages that evolved carotenoid-dependent coloration, with strong attraction toward this optimum. Hence, carotenoids do not appear to be limiting, given that higher carotenoid levels readily evolve in response to the evolution of carotenoid-dependent coloration. These findings challenge the assumption that carotenoids are a scarce resource and thus also challenge the hypothesis that physiological resource value of carotenoids underlies honesty of carotenoid-dependent traits. Therefore, the comparative evidence suggests that other factors, such as the acquisition and incorporation of carotenoids, are involved in maintaining signal honesty.