字神帝國英語天地

👑字神老師推薦：加強英聽力最好的課外教材：60-Second Science
👑康康精選各考試中重要主題，堅持精聽一定會進步的哦!
👑今日主題：Planting Milkweed for Monarchs? Make Sure it's Native / 為帝王蝶種植乳草？確保是本地的。

🍄建議堅聽四步驟：
1. 先聽兩三遍 (不看文稿)
2. 再一句一句聽寫 (每句都要聽寫數遍，直到寫出85%以上的字)
3. 最後check文稿，看哪聽不出來，單字沒背過，還是發音不熟。
4. 堅持天天聽，就能每天進步哦。

🍄MP3音檔 (按右鍵可下載聽)：喜歡的同學，幫忙推或按讚哦~~
https://bit.ly/2F9mPtv

🍄只有音檔怎夠，有聽不懂地方，不用怕，老師都幫你準備好中英文稿了哦：
🍄中英文稿：
Monarch butterflies depend on milkweed. They lay their eggs on milkweed, and their caterpillars eat only the leaves of the plant. No milkweed means no monarchs. So the best way to help declining monarch populations—and to preserve their epic, multi-generational migration—is to plant milkweed. Seems simple, right? But the reality is far more complicated.
帝王蝶以乳草為生，他們在乳草上產卵，毛毛蟲只吃這種植物的葉子。沒有乳草就意味著沒有帝王蝶。因此，幫助數量下降的帝王蝶，還有保持帝王蝶壯麗的、多世代遷移的最佳方式，就是種植乳草。這聽起來似乎很簡單，對吧？但現實情況要複雜得多。

Milkweed is slightly toxic—the plant evolved its noxious substances to keep herbivores from chowing down on the leaves. But monarch butterflies evolved tolerance. In fact, they arm themselves with the stuff. "Monarchs sequester these toxins as an anti-predator defense and anti-parasite defense." Louisiana State University biologist Matt Faldyn.

乳草具有輕微的毒性—植物進化出有毒物質，以防止食草動物啃食樹葉。但帝王蝶進化出抗毒性。實際上，他們用武器武裝自己。“帝王蝶把這些毒素隔離為一種反捕食者防禦和反寄生蟲防禦。”路易斯安那州立大學生物學家Matt Faldyn說。

So, by ingesting the toxin, the caterpillars become toxic themselves. That keeps them safe—as long as they don't ingest too much of the poison. The problem is there are different types of milkweed. And one that’s native to the tropics is now growing in the southern U.S. As these plants sense warming temperatures, they produce more of the toxin—so much more that the monarch butterflies begin to suffer.
因此，通過攝取毒素，毛蟲使自己變得有毒。這可以保證他們自身安全—只要不攝入太多的毒物即可。問題是有多種類型的乳草。而熱帶地區的本地種，現在在美國南部種植。由於這些植物感受到溫度升高，它們產生了更多的毒素—多到使得帝王蝶開始受到影響。

To gauge the threat, Faldyn and his team raised monarchs on either the non-native tropical milkweed or on a native milkweed. And they also tested the effects of current environmental conditions as well as temperatures expected for the southern U.S. by the year 2080.
為了評估威脅，Faldyn和他的團隊，在非本地熱帶乳草或本地乳草上培育帝王蝶。他們還測試了當前環境條件的影響，以及到2080年美國南部預計的溫度。

Monarchs that ate native milkweed had comparable survival rates at both current and higher temperatures. But under those future warmer conditions, monarchs raised on the tropical milkweed survived at only one-fifth the rate of butterflies raised under current conditions.
在當前和更高溫度下，吃本地乳草的帝王蝶，具有相當高的存活率。但在未來較溫暖的條件下，吃熱帶乳草生長的帝王蝶，存活率只有當前條件下飼養的蝴蝶的五分之一。

The monarchs could thus find themselves in what's known as an ecological trap. The butterflies seek out milkweed, but what is already the most common type of milkweed in the southern US will eventually kill them.
帝王蝶主因此可以發現自己處於所謂的生態陷阱之中。蝴蝶尋找乳草，但美國南部最常見的乳草，最終會殺死它們。

The tropical species is prettier than the native ones, which is why many people prefer to plant it. But there’s still time to change that. "What we show is that maybe there should be more of a focus on having native species to your area preferentially planted in your gardens."
熱帶物種比本地的更漂亮，這就是為什麼許多人喜歡種植的原因。但是現在還有時間來改變這種狀況。“我們展示的是，也許應該有更多的關注，讓本地物種優先種植在您的花園中。”

By switching to the native species, home gardeners across the country can each do their part to ensure that monarch butterflies will avoid fluttering their way into the ecological trap—which could be fatal.
通過轉換成本地物種，全國各地的家庭園藝家可以各盡其能，確保帝王蝶避免進入生態陷阱—這可能是致命的陷阱。
[原文出處: https://bit.ly/2jHGjgE]