SSS 2010-04-16
时间：2018-12-24 作者：英语课 分类：Scientific American(四)月
Invasive species can decrease biodiversity and drive resident species to the brink 1 of extinction 2. But how do these interlopers fare so well in unfamiliar 3 territory? One idea is that they’ve escaped their enemies, for example, the parasites 5 that keep them in check on their home turf. But a study in the journal Biology Letters suggests that notion doesn’t always stand up. Because at least one kind of invasive shrimp 6 is an even bigger pest when it has a parasite 4 on board.
The scientists were studying a freshwater shrimp commonly found in England. Fishermen brought the shrimp to Northern Ireland in the 1950s as a tasty treat for local trout 7. Well, the shrimp liked the new digs. So much that they’ve all but eliminated the native shrimp species. The strange thing is, they may have parasites to thank.
In some streams, 70 percent of the invaders 8 are infected with an intestinal 9 worm that doesn’t go for the native shrimp. But this gut 10 worm doesn’t slow them down. In fact, infected shrimp eat 30 percent more prey 11 than those that are parasite-free.
Which perhaps is not surprising. If you had a worm that constituted a quarter of your body weight, you’d eat more too.
Thanks for the minute for Scientific American's 60-Second Science. I'm Karen Hopkin.
- The tree grew on the brink of the cliff.那棵树生长在峭壁的边缘。
- The two countries were poised on the brink of war.这两个国家处于交战的边缘。
- The plant is now in danger of extinction.这种植物现在有绝种的危险。
- The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。
- I am unfamiliar with the place and the people here.我在这儿人地生疏。
- The man seemed unfamiliar to me.这人很面生。
- The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
- I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。
- These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
- Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。
- When the shrimp farm is built it will block the stream.一旦养虾场建起来，将会截断这条河流。
- When it comes to seafood,I like shrimp the best.说到海鲜，我最喜欢虾。
- Thousands of young salmon and trout have been killed by the pollution.成千上万的鲑鱼和鳟鱼的鱼苗因污染而死亡。
- We hooked a trout and had it for breakfast.我们钓了一条鳟鱼，早饭时吃了。
- They prepared to repel the invaders. 他们准备赶走侵略军。
- The family has traced its ancestry to the Norman invaders. 这个家族将自己的世系追溯到诺曼征服者。
- A few other conditions are in high intestinal obstruction. 其它少数情况是高位肠梗阻。 来自辞典例句
- This complication has occasionally occurred following the use of intestinal antiseptics. 这种并发症偶而发生在使用肠道抗菌剂上。 来自辞典例句
