Theories of animal signalling emphasize the importance of costliness-to be effective, signals must be dependable; to be dependable, signals must carry costs-and carotenoid-based signals are a favoured example. The traditional view that carotenoids are costly because they are scarce still carries weight. However, biomedical research has led to alternative views on costliness, mainly related to beneficial, but also to detrimental, effects of carotenoids. Recent improvements in our understanding of carotenoids suggest that the relative importance of these mechanisms will soon be determined, leading to a fresh outlook on cost-based signalling.

中文翻译：

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昂贵的性信号：类胡萝卜素是稀有，高风险还是必需的？

动物信号理论强调了成本重要性的重要性，要有效，信号必须可靠。为了可靠，信号必须承担成本，而基于类胡萝卜素的信号是一个受欢迎的例子。传统观点认为类胡萝卜素昂贵，因为它们很稀少，但仍然很重。但是，生物医学研究导致人们对成本高昂的看法不一，这主要与类胡萝卜素的有益作用有关，但也与有害作用有关。我们对类胡萝卜素的了解的最新进展表明，将很快确定这些机制的相对重要性，从而对基于成本的信号产生新的前景。