蝴蝶迁徙考古求确认

maylovemay · 发表于 2012-1-7 01:33:42

六、北美蝴蝶（帝王蝶）的迁徙

第1段：Monarch Butterfly夏天在加拿大南部生活，因为那里是它们的食物milkweed所能生长的最北端

第2段：Monarch Butterfly以rocky山脉为界生活在西边和东边。西边的在California过冬，而东边的在哪里过冬？1930年科学家决定suspecting东边的在哪里过冬，他们做了一个研究：夏天时在他们的翅膀上绑上东西，然后在由各地抓住的绑着东西的蝴蝶来汇总信息。经过很多年的mapping，得出它们在Mexico过冬。（这一段的研究需要什么作为保障）

第3段：further controversy：虫子们是一生下来就随着大部队在冬天去到了墨西哥，还是经过好多generation才到达墨西哥。最后终于明白了：是缘自于milkweed中的一种化学物质，这种poison随着milkweed所在地的不同而有不同的特性，当milkweed被虫子吃了后，这种物质去到一个叫puna的器官，然后在虫子体内积淀下来。因此研究一只抓到的虫子身上所含有的这个物质的特性就知道他在哪里生活过。它们要经过好几代才到墨西哥。

题目：对于第一段中提到的成就具有关键作用的是什么。

泾渭不凡 · 发表于 2012-1-7 08:34:39

帝王蝶？是成双成对，一只是无毒一只是剧毒的那种生物么？？
木事木事，大家忽略我，这里顶起。

泾渭不凡 · 发表于 2012-1-7 15:39:48

千与千寻117 · 发表于 2012-1-7 17:14:10

泾渭不凡 · 发表于 2012-1-7 20:39:13

清飞扬 · 发表于 2012-1-8 10:55:27

这篇跟JJ像吗

Brower has perfected a technique for tracking monarchs throughout the rest of the year, based on the butterflies' special relationship with milkweed plants. Monarchs lay their eggs on milkweed and, as larvae, eat the plants not only for nutrition but also for the toxins in the sap, which is poisonous to birds that prey on butterflies. The toxic compounds, known as cardiac glycosides, accumulate in larval tissues and persist after the larvae metamorphose into butterflies, making monarchs unpalatable to birds. "I've tasted the sap of the sandhill milkweed," says Brower, "and it's incredibly nauseating." Brower realized in the mid-1970s that he could use these poisons to understand monarch migration. The specific glycosides present in different species of milkweed vary from place to place, so analysis of a plant's glycosides can be used to determine its site of origin. Likewise, the glycosides in adult butterflies are a fingerprint of the plants on which the insects fed as larvae. "The light bulb went on," says Brower. His idea: If monarchs reflect the different arrays of glycosides in milkweeds, then he should be able to analyze butterfly glycosides and correlate individual insects with particular species of milkweed and with certain regions where the milkweed grew.
Traveling around the country, Brower trapped monarchs everywhere from the Great Lakes to Mexico and studied their glycosides. "We collected monarchs in the fall migration and established that over 90 percent fed on the northern milkweed pattern," he says. "Then we sampled the butterflies in Mexico and the ones along the Gulf Coast at the end of March and early April and, lo and behold, all of them had the same pattern. The same butterflies were going to Mexico and coming back in the spring."
Brower's work on glycosides helped to reveal the entire pattern of monarch migration. The first generation of monarch butterflies to return from Mexico stops along the Gulf Coast from Texas to Florida, where the insects lay eggs and die. The eggs hatch, and the new monarchs (with their distinctive southern milkweed fingerprint) head for the Great Lakes region. Later, the new generation of monarchs born around the Great Lakes flies to the East Coast, where they breed and die. Their offspring, fed on eastern milkweeds, then head south toward the Gulf Coast and on to Mexico, traveling as far as 90 miles per day and completing the great circle of monarch migration.

泾渭不凡 · 发表于 2012-1-8 10:57:42

清飞扬，太N了。。。。

清飞扬 · 发表于 2012-1-8 11:01:11

来个人确认下吧

ivyxiaoxiao · 发表于 2012-1-8 11:47:14

泾渭不凡 · 发表于 2012-1-8 23:25:36

[考古] 蝴蝶迁徙考古求确认

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