Immune activation rapidly mirrored in a secondary sexual trait
Immune activation rapidly mirrored in a secondary sexual trait
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DOI：
10.1126/science.1081802
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发表时间：
2003-04-04
期刊：
影响因子：
56.9
通讯作者：
Sorci, G
中科院分区：
文献类型：
--
作者：
Faivre, B;Grégoire, A;Sorci, G
大多数性选择模型的一个关键假设是，性广告真实地反映了其承载者的表型和/或遗传质量（1）。在这里，我们表明，实验激活的免疫系统是迅速反映在表达的类胡萝卜素为基础的第二性征在男性黑鸟（Turdus merula）。这一结果表明，性广告诚实的信号男性的健康，可以可靠地使用同种作为一个线索的个人质量在内部和/或intersexual interactions.Male乌鸫表现出黑色的羽毛与黄色到橙子法案，而女性是褐色的棕色法案。最近的研究表明，法案的颜色是一个性选择性状在黑鸟（2，3）。例如，雄性黑鹂对橙子喙的坐骑比对黄色喙的坐骑更具攻击性（2）。因此，比尔色素沉着可能提供了一个信号，用于在男性之间的竞争（2）。此外，与黄色喙的雄性相比，橙子喙的雄性黑鸟与身体状况更好的雌性交配，并繁殖更多的后代（3）。总的来说，这些结果表明，法案的颜色在性选择中的作用，可能作为一个指标的男性表型质量。类胡萝卜素是动物交流中使用的彩色信号的常见成分（4）。它们在上调免疫功能的各个方面（5）和细胞保护免受自由基（6）方面也很重要。这表明类胡萝卜素分配给性信号与免疫防御之间可能存在权衡（4）。使用自动进样器高效液相色谱仪，我们确定了雄性黑鸟喙中沉积的类胡萝卜素的存在[见注释（S1）]（7）。对吸收光谱的分析揭示了β-胡萝卜素、β-隐黄质、玉米黄质和叶黄素的存在（图1A）。为了调查是否票据颜色反映免疫状态，我们免疫圈养雄性黑鸟与悬浮液的绵羊红细胞（SRBC）在1999年春季（n 19）和2002年春季（n 13）。对照组（n 15）于2002年注射磷酸盐缓冲盐水溶液（PBS）作为对照。只有2002只鸟被用来作为一个假设的直接测试，免疫激活减少了第二性征的表达，通过比较变化，
A crucial assumption underlying most models of sexual selection is that sexual advertisements honestly reflect the phenotypic and/or genetic quality of their bearers (1). Here we show that experimental activation of the immune system is rapidly mirrored in the expression of a carotenoid-based secondary sexual trait in male blackbirds (Turdus merula). This result shows that sexual advertisement honestly signals male health and can be reliably used by conspecifics as a cue of individual quality during intra-and/or intersexual interactions.Male blackbirds exhibit a black plumage with a yellow to orange bill, whereas females are brownish with a brown bill. Recent studies have suggested that bill color is a sexually selected trait in blackbirds (2, 3). For example, resident male blackbirds are more aggressive to mounts with orange bills than to mounts with yellow bills (2). Bill pigmentation might therefore provide a signal used during contests between males (2). In addition, male blackbirds with orange bills are mated with females in better body condition and fledge more offspring than males with yellow bills (3). Overall, these results suggest a role for bill color in sexual selection, possibly as an indicator of male phenotypic quality. Carotenoids are common components of colored signals used in animal communication (4). They are also important in the up-regulation of various aspects of the immune functioning (5) and cellular protection against free radicals (6). This suggests that a trade-off may exist between allocation of carotenoids to sexual signaling versus immune defenses (4). Using an autosampler high-performance liquid chromatographer, we determined the presence of carotenoids deposited in the bill of male blackbirds [see note (S1)](7). The analysis of the absorption spectrum revealed the presence of-and-carotene,-cryptoxanthin, zeaxanthin, and lutein (Fig. 1A). To investigate whether bill color reflects immune status, we immunized captive male blackbirds with a suspension of sheep red blood cells (SRBC) in both spring 1999 (n 19) and spring 2002 (n 13). A control group (n 15) was injected with a phosphate-buffered saline solution (PBS) for control in 2002. Only the 2002 birds were used as a direct test of the hypothesis that immune activation reduces the expression of the secondary sexual trait, by comparing changes