Multiple receivers, multiple ornaments, and a trade-off between agonistic and epigamic signaling in a widowbird
Multiple receivers, multiple ornaments, and a trade-off between agonistic and epigamic signaling in a widowbird
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DOI：
10.1086/342817
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发表时间：
2002-11-01
影响因子：
2.9
通讯作者：
Andersson, M
中科院分区：
文献类型：
--
作者：
Andersson, S;Pryke, SR;Andersson, M
性展示通常涉及几种不同的装饰特征。然而，大多数基于单个接收者（通常是挑剔的雌性）的性选择指标模型发现，多个障碍信号应该是不稳定的。在这里，我们研究了这种矛盾的原因，分析了一夫多妻制红领寡妇鸟 Euplectes ardens 的信号功能、信号内容以及信号之间的权衡。雄性有一条长长的、有刻度的尾巴和一个红色的类胡萝卜素领章。占据领地的“居民”的尾巴比非繁殖的“飞蚊”稍短，但它们的类胡萝卜素项圈要大 40%，并且（根据反射光谱测定和客观比色法）它们的长波（“更红”）色调比飞蚊多 23 纳米。这证实了实验证据，即红项圈是由雄性竞赛选择的，而雌性的选择几乎完全基于雄性尾巴的长度。尾长与类胡萝卜素信号呈负相关，与体型和状况一起解释了尾长变化的 55%。尾长和类胡萝卜素投资之间的权衡在居民中更为明显，这表明与领土防御成本之间存在相互作用。我们提出“多接收器假说”可以解释多个障碍信号的共存。此外，信号表达之间的权衡可能有助于Euplectes属（主教鸟和寡妇鸟）的婚尾伸长和着色之间的反比关系。
Sexual displays often involve several different ornamental traits. Yet most indicator models of sexual selection based on a single receiver (usually a choosy female) find that multiple handicap signals should be unstable. Here we study reasons for this contradiction, analyzing signal function, signal content, and trade-offs between signals in the polygynous red-collared widowbird Euplectes ardens. Males have both a long, graduated tail and a red carotenoid collar badge. Territory-holding "residents" have slightly shorter tails than the nonbreeding "floaters," but their carotenoid collars are 40% larger, and they have (on the basis of reflectance spectrometry and objective colorimetry) a 23-nm more long-wave ("redder") hue than floaters. This corroborates experimental evidence that the red collar is selected by male contest competition, whereas female choice is based almost exclusively on male tail length. Tail length is negatively correlated with the carotenoid signal, which together with body size and condition explains 55% of the variation in tail length. The trade-off in tail length and carotenoid investment is steeper among residents, suggesting an interaction with costs of territory defense. We propose that the "multiple receiver hypothesis" can explain the coexistence of multiple handicap signals. Furthermore, the trade-off between signal expressions might contribute to the inverse relation between nuptial tail elongation and coloration in the genus Euplectes (bishops and widowbirds).