Knee-clicks and visual traits indicate fighting ability in eland antelopes: multiple messages and back-up signals
Knee-clicks and visual traits indicate fighting ability in eland antelopes: multiple messages and back-up signals
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DOI：
10.1186/1741-7007-6-47
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发表时间：
2008-11-05
期刊：
影响因子：
5.4
通讯作者：
Dabelsteen, Torben
中科院分区：
文献类型：
--
作者：
Bro-Jorgensen, Jakob;Dabelsteen, Torben
背景：考虑到发出信号的成本，为什么雄性经常用几个信号而不是一个信号向对手宣传自己的战斗能力？多种信号理论主要是在性信号的研究中发展起来的，但对它们在性内交流中的适用性知之甚少。在这里，我们调查的进化基础复杂的激动信号系统在大羚羊，特别注意大声knee-clicking.Results的进化现象：主成分分析分离7个男性特征分为三组。膝关节咔嗒声的主要频率真实地表明了身体的大小，这是战斗能力的主要决定因素。相比之下，赘肉的大小增加估计年龄，而不是身体的大小，这表明，通过放大老年公牛的轮廓不成比例，赘肉作为一个指标的年龄相关的特征，如战斗经验。面罩颜色、前额发刷大小和身体灰色与第三个潜在变量一致，推测是雄激素相关的攻击性。纵向研究提供了独立的支持，这些findings.Conclusion：结果表明，在eland的多个激动信号反映了三个独立的组成部分的战斗能力：（1）身体大小，（2）年龄和（3）推测雄激素相关的侵略，这是反映在三个备份信号。这项研究强调了复杂的激动性信号系统如何通过几种选择性力量的同时作用而进化，每种选择性力量都有利于多种信号。具体来说，响亮的膝盖点击被发现是身体大小的诚实信号，提供了一个特殊的例子，在哺乳动物中的非声乐声学通信的潜力。
Background: Given the costs of signalling, why do males often advertise their fighting ability to rivals using several signals rather than just one? Multiple signalling theories have developed largely in studies of sexual signals, and less is known about their applicability to intra-sexual communication. We here investigate the evolutionary basis for the intricate agonistic signalling system in eland antelopes, paying particular attention to the evolutionary phenomenon of loud knee-clicking.Results: A principal components analysis separated seven male traits into three groups. The dominant frequency of the knee-clicking sound honestly indicated body size, a main determinant of fighting ability. In contrast, the dewlap size increased with estimated age rather than body size, suggesting that, by magnifying the silhouette of older bulls disproportionately, the dewlap acts as an indicator of age-related traits such as fighting experience. Facemask darkness, frontal hairbrush size and body greyness aligned with a third underlying variable, presumed to be androgen-related aggression. A longitudinal study provided independent support of these findings.Conclusion: The results show that the multiple agonistic signals in eland reflect three separate components of fighting ability: (1) body size, (2) age and (3) presumably androgen-related aggression, which is reflected in three backup signals. The study highlights how complex agonistic signalling systems can evolve through the simultaneous action of several selective forces, each of which favours multiple signals. Specifically, loud knee-clicking is discovered to be an honest signal of body size, providing an exceptional example of the potential for non-vocal acoustic communication in mammals.