Oliveriusová Ludmila, Němec Pavel, Pavelková Zuzana, Sedláček František
Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic,
Naturwissenschaften. 2014 Jul;101(7):557-63. doi: 10.1007/s00114-014-1192-0. Epub 2014 Jun 10.
Magnetoreception has been convincingly demonstrated in only a few mammalian species. Among rodents, magnetic compass orientation has been documented in four species of subterranean mole rats and two epigeic (i.e. active above ground) species-the Siberian hamster and the C57BL/6J mouse. The mole rats use the magnetic field azimuth to determine compass heading; their directional preference is spontaneous and unimodal, and their magnetic compass is magnetite-mediated. By contrast, the primary component of orientation response is learned in the hamster and the mouse, but both species also exhibit a weak spontaneous bimodal preference in the natural magnetic field. To determine whether the magnetic compass of wild epigeic rodents features the same functional properties as that of laboratory rodents, we investigated magnetic compass orientation in the bank vole Clethrionomys glareolus (Cricetidae, Rodentia). The voles exhibited a robust spontaneous bimodal directional preference, i.e. built nests and slept preferentially along the north-south axis, and deflected their directional preference according to a shift in the direction of magnetic north, clearly indicating that they were deriving directional information from the magnetic field. Thus, bimodal, axially symmetrical directional choice seems to be a common feature shared by epigeic rodents. However, spontaneous directional preference in the bank vole appeared to be more pronounced than that reported in the hamster and the mouse. These findings suggest that bank voles are well suited for future studies investigating the adaptive significance and mechanisms of magnetic orientation in epigeic rodents.
磁感受仅在少数哺乳动物物种中得到了令人信服的证明。在啮齿动物中，已记录到四种地下鼹形鼠和两种地表活动（即在地面以上活动）的物种——西伯利亚仓鼠和C57BL/6J小鼠具有磁罗盘定向能力。鼹形鼠利用磁场方位来确定罗盘方向；它们的方向偏好是自发的且单峰的，其磁罗盘由磁铁矿介导。相比之下，仓鼠和小鼠的定向反应主要成分是后天习得的，但这两个物种在自然磁场中也表现出微弱的自发双峰偏好。为了确定野生地表活动啮齿动物的磁罗盘是否具有与实验室啮齿动物相同的功能特性，我们研究了棕背䶄（仓鼠科，啮齿目）的磁罗盘定向。棕背䶄表现出强烈的自发双峰方向偏好，即筑巢和睡觉优先沿着南北轴进行，并根据磁北方向的变化改变其方向偏好，这清楚地表明它们从磁场中获取方向信息。因此，双峰、轴向对称的方向选择似乎是地表活动啮齿动物共有的一个共同特征。然而，棕背䶄的自发方向偏好似乎比仓鼠和小鼠中报道的更为明显。这些发现表明，棕背䶄非常适合未来研究地表活动啮齿动物磁定向的适应性意义和机制。
