墨西哥利用国际原子能机构数据研究蝴蝶迁徙

The study revealed that, to survive the winter, four out of the six butterfly species travelled from the North of the United States or from Southern Canada to Mexico. The study also revealed further information on the migration style of the butterfly species.

It found that the American Snout butterfly (Libytheana carinenta) had the longest migration route and that its migration was a “chain migration”. This means that the American Snout butterflies born in the northern parts of the subcontinent were found to settle in Mexico for the winter only after those born in the southern parts had already migrated further south.

The Queen butterfly (Danaus gilippus), on the other hand, was observed to have performed “leapfrog migration” within the subcontinent. This means that individual Queen butterflies born in southern parts of the subcontinent made a short journey further south. Their northern-born counterparts, however, were found to have travelled further south than the southern-born butterflies for the winter, in other words “leapfrogging” past those born in more southern areas.

A third species, the Dogface butterfly (Zerene cesonia), was shown to practice “panmixia”, meaning that the individual butterflies would mix with one another and settle together during the migration path, regardless of their region of origin.

To study the migration paths of the six species, scientists collected samples of butterflies that had been killed by passing cars on a specific mountain valley road popular with several types of migrating butterflies. The samples were collected between September and November 2019. To establish the migration path, the scientists determined their place of birth by analysing the deuterium in their wings and by comparing it to the data on rain isotopes present in an IAEA database (click here for more information on the technique).

“This type of research is important because, on the one hand, it helps us understand the evolution of the patterns in animals, and on the other hand, from a conservation perspective, it helps us to predict which populations may be more vulnerable to events along the migration route, such as climate events, car collisions and habitat loss,” said Keith Hobson, researcher of the University of Western Ontario in Canada and co-author of the study.