Why do some traits show higher fluctuating asymmetry than others? A test of hypotheses with tail feathers of birds
Why do some traits show higher fluctuating asymmetry than others? A test of hypotheses with tail feathers of birds
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DOI：
10.1038/sj.hdy.6800118
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发表时间：
2002-08-01
期刊：
影响因子：
3.8
通讯作者：
Bonal, R
中科院分区：
文献类型：
--
作者：
Aparicio, JM;Bonal, R
某些性状比其他性状更容易受到波动不对称性（FA）增加的影响。这种性状特异性易感性通常归因于不同程度的发育稳定性，这可能是由不同的选择模式、功能或发育过程中经历的压力引起的。最近，也有人提出，FA的表达不仅取决于发育稳定性，而且还取决于性状的生长成本，定义为形成给定性状的长度单位所需的结构成分的量。根据这一论点，每单位长度具有更多结构成分的性状应该比简单性状表现出更低的不对称性。为了验证这一假设，我们研究了26种鸟类最长尾羽的结构（倒钩数量，倒钩长度和羽轴宽度）和不对称性。回归分析，使用非遗传独立的对比表明，FA是负相关的倒钩和羽轴宽度的男性（包括物种与细长的尾巴进行性选择），和轴宽度的女性，其尾巴应该演变的自然选择。此外，FA和轴宽度之间的负相关持续时，只采取非二型物种的男性。这些结果证实了这一假设，表明一个性状的易感性，以表达发展不稳定波动的不对称性取决于其结构组成。
Certain characters are more susceptible to increased fluctuating asymmetry (FA) than others. This trait-specific susceptibility has normally been attributed to different degrees of developmental stability, which could be caused by different modes of selection, functionality, or the stress experienced during the development process. Recently, it has also been suggested that the expression of FA not only depends on developmental stability, but also on the cost of growth of the trait, defined as the amount of structural components necessary to form a unit of length of a given character. In accordance with this argument, a trait with more structural components per unit of length should show lower asymmetry than a simpler one. To test this hypothesis, we examine the structure (number of barbs, barb length, and rachis width) and asymmetry of the longest tail feathers in 26 bird species. Regression analyses using phylogenetically independent contrasts show that FA is negatively correlated with the number of barbs and feather rachis width in males (including species with elongated tails subjected to sexual selection), and with rachis width in females, whose tails supposedly evolve by natural selection. Moreover, the negative correlation between FA and rachis width persisted when taking only the males of non-dimorphic species. These results confirm the hypothesis, suggesting that a trait's susceptibility to express developmental instability by fluctuating asymmetry depends on its structural composition.