美国北卡罗来纳大学Kenneth J. Lohmann团队近日取得一项新成果。经过不懈努力，他们开发出海龟学习磁图线索和两种磁接受机制。这一研究成果于2025年2月12日发表在国际顶尖学术期刊《自然》上。

在这里，研究小组报告了一种标志性的导航物种，红海龟（Caretta Caretta），可以学习这些信息。当在复制特定海洋区域磁场的环境中反复喂食时，幼年海龟学会了区分它们遇到食物的磁场和其他地方存在的磁场，这种能力可能是觅食地点保真度的基础。在这种新的磁图分析中，条件反应不受射频振荡磁场的影响，这种处理有望破坏基于自由基对的化学磁接受，这表明海龟的磁图感觉并不依赖于这种机制。与此相反，射频振荡磁场干扰了磁罗盘的定向行为。这些发现提供了证据，证明海龟的磁图和磁罗盘是由两种不同的磁接收机制构成的。

据了解，越来越多的证据表明，迁徙动物利用地球的磁场来导航，既可以作为指南针来确定方向，又可以作为地图来确定地理位置。长期以来一直有人提出，为了在磁地图上导航，动物可以学习目的地的磁坐标，然而，动物可以学习地理区域的磁特征这一关键假设，据它们所知，还有待验证。

附：英文原文

Title: Learned magnetic map cues and two mechanisms of magnetoreception in turtles

Author: Goforth, Kayla M., Lohmann, Catherine M. F., Gavin, Andrew, Henning, Reyco, Harvey, Andrew, Hinton, Tara L., Lim, Dana S., Lohmann, Kenneth J.

Issue&Volume: 2025-02-12

Abstract: Growing evidence indicates that migratory animals exploit the magnetic field of the Earth for navigation, both as a compass to determine direction and as a map to determine geographical position1. It has long been proposed that, to navigate using a magnetic map, animals must learn the magnetic coordinates of the destination2,3, yet the pivotal hypothesis that animals can learn magnetic signatures of geographical areas has, to our knowledge, yet to be tested. Here we report that an iconic navigating species, the loggerhead turtle (Caretta caretta), can learn such information. When fed repeatedly in magnetic fields replicating those that exist in particular oceanic locations, juvenile turtles learned to distinguish magnetic fields in which they encountered food from magnetic fields that exist elsewhere, an ability that might underlie foraging site fidelity. Conditioned responses in this new magnetic map assay were unaffected by radiofrequency oscillating magnetic fields, a treatment expected to disrupt radical-pair-based chemical magnetoreception4,5,6, suggesting that the magnetic map sense of the turtle does not rely on this mechanism. By contrast, orientation behaviour that required use of the magnetic compass was disrupted by radiofrequency oscillating magnetic fields. The findings provide evidence that two different mechanisms of magnetoreception underlie the magnetic map and magnetic compass in sea turtles.

DOI: 10.1038/s41586-024-08554-y

Source: https://www.nature.com/articles/s41586-024-08554-y