Department of Biological Sciences, University of Windsor, , Windsor, Ontario, Canada , N9A 2N2.
Biol Lett. 2010 Feb 23;6(1):63-6. doi: 10.1098/rsbl.2009.0604. Epub 2009 Sep 30.
Sexual selection often promotes the evolution of elaborate colour signals in males, but the importance of sexually selected colour signals remains poorly studied in amphibians. We used reflectance spectrometry to document pronounced sexual dichromatism and dramatic colour change in Bufo luetkenii, a toad that breeds in large aggregations at the onset of the rainy season in Costa Rica. Our observations suggest that males fade rapidly from a vibrant lemon yellow to a dull brown once they have paired with a female. We demonstrate this by showing that males are much brighter than females and that unpaired males are more colourful than males in amplexus. We also show that coloration fades rapidly when males are briefly held captive. This is, to our knowledge, the first study to document such dynamic change in male coloration and sexual dichromatism in anurans.
性选择常常促进雄性动物中复杂的颜色信号的进化，但在两栖动物中，性选择的颜色信号的重要性仍研究不足。我们使用反射光谱法记录了 Costa Rica 雨季开始时大量聚集繁殖的蟾蜍 Bufo luetkenii 明显的两性异形和戏剧性的颜色变化。我们的观察表明，雄性一旦与雌性配对，就会迅速从鲜艳的柠檬黄色褪变为暗淡的棕色。我们通过展示雄性比雌性更亮，未配对的雄性比交配中的雄性颜色更鲜艳来证明这一点。我们还表明，当雄性被短暂囚禁时，颜色会迅速褪色。据我们所知，这是第一项记录两栖动物中雄性颜色和两性异形如此动态变化的研究。
