Wiltschko Wolfgang, Freire Rafael, Munro Ursula, Ritz Thorsten, Rogers Lesley, Thalau Peter, Wiltschko Roswitha
FB Biowissenschaften, J. W. Goethe-Universität Frankfurt, D-61231 Frankfurt am Main, Germany.
J Exp Biol. 2007 Jul;210(Pt 13):2300-10. doi: 10.1242/jeb.004853.
By directional training, young domestic chickens have been shown to use a magnetic compass; the same method has now been used to analyse the functional characteristics and the physical principles underlying the chickens' magnetic compass. Tests in magnetic fields with different intensities revealed a functional window around the intensity of the local geomagnetic field, with this window extending further towards lower than higher intensities. Testing chickens under monochromatic 465 nm blue and 645 nm red light suggested a wavelength dependence, with orientation possible under blue but not under red light. Exposing chickens to an oscillating field of 1.566 MHz led to disorientation, identifying an underlying radical pair mechanism. Local anesthesia of the upper beak, where iron-rich structures have been described as potential magnetoreceptors, did not affect the performance, suggesting that these receptors are not involved in compass orientation. These findings show obvious parallels to the magnetic compass described for European robins, indicating that chickens and small passerines use the same type of magnetic compass mechanism. This suggests that the avian magnetic compass may have evolved in the common ancestor of all present-day birds to facilitate orientation within the home range.
通过定向训练，已证明幼雏鸡能够使用磁罗盘；现在已使用相同方法来分析鸡磁罗盘的功能特性和物理原理。在不同强度磁场中的测试揭示了围绕当地地磁场强度的一个功能窗口，该窗口向较低强度方向的延伸比向较高强度方向的延伸更远。在单色465纳米蓝光和645纳米红光下对鸡进行测试表明存在波长依赖性，在蓝光下鸡可以定向，但在红光下则不能。将鸡暴露于1.566兆赫的振荡场中会导致定向障碍，这确定了一种潜在的自由基对机制。对上喙进行局部麻醉（上喙中富含铁的结构被描述为潜在的磁感受器）并未影响其表现，这表明这些感受器不参与罗盘定向。这些发现与描述欧洲知更鸟的磁罗盘有明显相似之处，表明鸡和小型雀形目鸟类使用相同类型的磁罗盘机制。这表明鸟类的磁罗盘可能在所有现代鸟类的共同祖先中就已进化出来，以促进在活动范围内的定向。
