Stalleicken Julia, Mukhida Maya, Labhart Thomas, Wehner Rüdiger, Frost Barrie, Mouritsen Henrik
VW Nachwuchsgruppe Animal Navigation, IBU, University of Oldenburg, D-26111 Oldenburg, Germany.
J Exp Biol. 2005 Jun;208(Pt 12):2399-408. doi: 10.1242/jeb.01613.
To test if migratory monarch butterflies use polarized light patterns as part of their time-compensated sun compass, we recorded their virtual flight paths in a flight simulator while the butterflies were exposed to patches of naturally polarized blue sky, artificial polarizers or a sunny sky. In addition, we tested butterflies with and without the polarized light detectors of their compound eye being occluded. The monarchs' orientation responses suggested that the butterflies did not use the polarized light patterns as a compass cue, nor did they exhibit a specific alignment response towards the axis of polarized light. When given direct view of the sun, migratory monarchs with their polarized light detectors painted out were still able to use their time-compensated compass: non-clockshifted butterflies, with their dorsal rim area occluded, oriented in their typical south-southwesterly migratory direction. Furthermore, they shifted their flight course clockwise by the predicted approximately 90 degrees after being advance clockshifted 6 h. We conclude that in migratory monarch butterflies, polarized light cues are not necessary for a time-compensated celestial compass to work and that the azimuthal position of the sun disc and/or the associated light-intensity and spectral gradients seem to be the migrants' major compass cue.
为了测试迁徙的帝王蝶是否将偏振光模式作为其时间补偿太阳罗盘的一部分，我们在飞行模拟器中记录了它们的虚拟飞行路径，同时让蝴蝶暴露在自然偏振的蓝天斑块、人工偏振器或晴朗天空下。此外，我们还测试了复眼的偏振光探测器被遮挡和未被遮挡的蝴蝶。帝王蝶的定向反应表明，蝴蝶并未将偏振光模式用作罗盘线索，它们也未对偏振光轴表现出特定的对齐反应。当能直接看到太阳时，其偏振光探测器被涂黑的迁徙帝王蝶仍能够使用它们的时间补偿罗盘：非时钟移位的蝴蝶，其背缘区域被遮挡，仍朝着其典型的西南偏南迁徙方向定向。此外，在被提前6小时时钟移位后，它们将飞行路线顺时针偏移了预计的约90度。我们得出结论，在迁徙的帝王蝶中，偏振光线索对于时间补偿天体罗盘的工作并非必要，太阳圆盘的方位位置和/或相关的光强度及光谱梯度似乎是迁徙者的主要罗盘线索。
