An experimental displacement and over 50 years of tag-recoveries show that monarch butterflies are not true navigators
An experimental displacement and over 50 years of tag-recoveries show that monarch butterflies are not true navigators
复制标题
DOI：
10.1073/pnas.1221701110
复制
发表时间：
2013-04-30
影响因子：
11.1
通讯作者：
Norris, D. Ryan
中科院分区：
文献类型：
--
作者：
Mouritsen, Henrik;Derbyshire, Rachael;Norris, D. Ryan
在北美东部繁殖的帝王蝶 (Danaus plexippus) 因其每年秋季迁徙到墨西哥越冬地而闻名。然而，人们对它们成功到达这些地点的机制仍知之甚少。在这里，我们测试君主是否是真正的航海家，他们可以使用“指南针”和“地图”来确定相对于最终目的地的位置。使用飞行模拟器，我们记录了安大略省西南部野生捕获的帝王蝶的方向，发现它们通常朝西南方向飞向越冬地。当向西移动 2,500 公里时，这些个体继续沿大致西南方向飞行，这表明帝王蝶使用了简单的矢量导航策略（即使用特定的罗盘方位而不补偿位移）。使用超过 5 年的现场数据，我们还表明，标记帝王蝶的方向集中度和回收角 SD 在很大程度上符合两个数学模型，这两个模型描述了矢量导航策略下预期的迁徙者的方向分布。对标记恢复的第三次分析表明，从北向南迁徙的方向性日益增强，很大程度上是因为引导个体前往越冬地点的地理障碍的存在。我们的研究表明，在北美东部繁殖的帝王蝶很可能将简单的定向机制与地理特征结合起来，将它们引导到墨西哥的越冬地点，考虑到这些蝴蝶的重量不到一克，并且飞行数千公里到达它们从未见过的地点，这是一项了不起的成就。
Monarch butterflies (Danaus plexippus) breeding in eastern North America are famous for their annual fall migration to their overwintering grounds in Mexico. However, the mechanisms they use to successfully reach these sites remain poorly understood. Here, we test whether monarchs are true navigators who can determine their location relative to their final destination using both a "compass" and a "map". Using flight simulators, we recorded the orientation of wild-caught monarchs in southwestern Ontario and found that individuals generally flew in a southwest direction toward the wintering grounds. When displaced 2,500 km to the west, the same individuals continued to fly in a general southwest direction, suggesting that monarchs use a simple vector-navigation strategy (i.e., use a specific compass bearing without compensating for displacement). Using over 5 decades of field data, we also show that the directional concentration and the angular SD of recoveries from tagged monarchs largely conformed to two mathematical models describing the directional distribution of migrants expected under a vector-navigation strategy. A third analysis of tagged recoveries shows that the increasing directionality of migration from north to south is largely because of the presence of geographic barriers that guide individuals toward overwintering sites. Our work suggests that monarchs breeding in eastern North America likely combine simple orientation mechanisms with geographic features that funnel them toward Mexican overwintering sites, a remarkable achievement considering that these butterflies weigh less than a gram and travel thousands of kilometers to a site they have never seen.