Combination of local selection pressures drives diversity in aposematic signals
Combination of local selection pressures drives diversity in aposematic signals
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DOI：
10.1007/s10682-011-9471-0
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发表时间：
2011-09-01
影响因子：
1.9
通讯作者：
Mochida, Koji
中科院分区：
文献类型：
--
作者：
Mochida, Koji
警示语信号的多样性是理解警示语进化过程中最困难的现象之一，因为警示语动物在常见时得到了最有效的保护。理论和实验研究预测，局部选择压力的组合可以保持警告信号的变化。然而，将这一假设应用于除模仿系统之外的警示性信号的大规模地理变异，还有待经验检验。我调查了蝾螈（Cynops pyrrhogaster）形态和行为警示信号的地理差异，以及它们在800多公里纬度范围内的种群所面临的捕食压力。实地实验表明，捕食压力的地方差异很好地解释了岛屿与大陆之间蝾螈警示颜色和行为的差异。此外，我发现在警示性颜色上有纬度梯度，但在行为上没有，独立于捕食压力。结果表明，由于捕食压力的地方差异，岛屿与大陆之间的警告信号差异也可能受到温度、体型差异和遗传差异等因素的影响，这些因素可能对每种警告特征产生不同的作用。
The diversity of aposematic signals is one of the most difficult phenomena for understanding the evolution of such signals because aposematic animals are most effectively protected when they are common. Theoretical and experimental studies predict that a combination of local selection pressures could maintain variation in aposematic signals. However, the application of this hypothesis to large-scale geographic variation in aposematic signals, other than mimicry systems, is yet to be tested empirically. I investigated geographic variation in morphological and behavioural aposematic signals of the newts, Cynops pyrrhogaster, and in predation pressures on them in populations ranging over 800 km of latitude. Field experiments demonstrated that local differences in predation pressures explain well the island-mainland variation in the aposematic colouration and behaviour of newts. Furthermore, I found a latitudinal gradient in aposematic colouration but not in behaviour, independent of predation pressures. The results suggested that island-mainland variation in aposematic signals resulting from local differences in predation pressures might also be shaped by several factors, such as temperature, body size variation, and genetic differences, and such factors might act on each aposematic trait differently.