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听力文本
Scientists Identify Chemical that Causes Locusts to Swarm
Scientists say they have identified a chemical released by locusts that causes the insects to join together in huge swarms.
On their own, locusts are mostly harmless. But in large swarms, they can be extremely destructive. The new finding could lead to new methods to prevent locusts from joining groups to destroy huge areas of crops.
A recent study published in Nature identifies a pheromone believed to be responsible for the insect's swarming behavior. A pheromone is a chemical substance produced by an animal that influences the behavior of another animal of the same kind.
The pheromone, known as 4VA, was found in the world's most widespread kind of locust, the migratory locust. The chemical is released from the insect's back legs and is sensed by the antennae of other locusts.
The pheromone powerfully drew locusts of both sexes and all ages, the research found. The chemical was produced when as few as four to five locusts came together.
Swarms can grow to billions of locusts and cover hundreds of square kilometers. Migratory locusts are found in Asia, Africa, Australia and New Zealand. They attack crops including wheat, rice, corn, oats and sugarcane. Such invasions can lead to major food shortages.
Lead researcher Le Kang is with the Chinese Academy of Sciences' Institute of Zoology. He told Reuters news agency that migratory locusts are so widespread and dangerous, they represent "a serious threat to agriculture worldwide."
Kang said further research will be needed to find out if 4VA exists in other species, such as the desert locust. This locust is currently destroying crops in Africa and the Middle East.
Chemical substances commonly used to break up locust swarms raise concerns for human health and safety. The identification of 4VA could lead to new control methods.
Kang said a chemical could be developed to block 4VA's effects to prevent swarming. A manmade version of the pheromone might also be developed to lure locusts into traps to be killed.
Locusts could also be developed with genetic changes that would not react to 4VA, Kang added. Such locusts could be released to establish wild non-swarming populations.
Leslie Vosshall is head of Rockefeller University's Laboratory of Neurogenetics and Behavior in New York. She said one of the most exciting developments would be finding a chemical that could block the reception of 4VA.
The discovery of such a molecule could provide a chemical to prevent swarms of the insects and "cause locusts to 'stand down' and return to their peaceful, solitary way of life," she wrote in a Nature article about the study.
Vosshall noted that there are still several unknowns about the research. These include whether 4VA is the only cause of swarm formation, and whether other locust species respond similarly to the compound.
I'm Bryan Lynn.
重点解析
重点讲解：
1. be responsible for 负有责任的；应承担责任的；
The sun's ultraviolet rays are responsible for both tanning and burning.
阳光中的紫外线是皮肤晒黑和灼伤的根源。
2. find out (尤指特意通过努力)发现，找出，查明；
They had their tablets analysed to find out whether they were getting the real drug or not.
他们将药片拿去化验以查明他们得到的是否是真药。
3. break up 散（会）；（使）解散；
Police used tear gas to break up a demonstration.
警察使用催泪瓦斯驱散示威人群。
4. return to 恢复，回到(原来的状态)；
Bank of England officials continued to insist that the pound would soon return to stability but disaster struck.
英格兰银行官员仍然坚持说英镑不久就会恢复稳定，但结果灾难爆发了。
参考译文
科学家找到引发蝗虫群的化学物质
科学家表示，他们找到了蝗虫释放的一种化学物质，该物质导致蝗虫聚集成群。
蝗虫本身基本上是无害的。但聚集成群后，它们可能会极具破坏力。这项新发现可能有助于开发出新方法，防止蝗虫聚集成群后破坏大面积作物。
近日发表在《自然》期刊上的一项研究表明，一种信息素被认为是导致蝗虫聚集成群的原因。信息素是动物产生的化学物质，能影响其他同类动物的行为。
这种信息素名为4-乙烯基苯甲醚（简称4VA），在世界上分布最广的蝗虫——飞蝗中发现。这种化学物质从飞蝗后腿释放出来，可被其他飞蝗的触角感知到。
研究发现，这种信息素可以有效地吸引雌性、雄性和所有年龄层的飞蝗。四到五只蝗虫聚集在一起就可以产生该化学物质。
蝗虫群的数量可壮大到数十亿只，覆盖数百平方公里。亚洲、非洲、澳大利亚和新西兰都有飞蝗。它们会攻击小麦、水稻、玉米、燕麦和甘蔗等作物。这种入侵会导致严重的粮食短缺。
首席研究员康乐来自中国科学院动物研究所。他对路透社表示，飞蝗分布广泛且具危险性，对“全世界农业构成严重威胁”。
康乐表示，需要进行进一步研究以确定4-乙烯基苯甲醚是否存在于其他蝗虫物种中，比如沙漠蝗虫。这种蝗虫正在摧毁非洲和中东地区的作物。
驱散蝗虫常用的化学物质引发了人们对人类健康和安全的担忧。而4-乙烯基苯甲醚的发现可能催生出新控制方法。
康乐表示，可以研发出一种化学物质来阻止4-乙烯基苯甲醚的作用，继而防止形成蝗虫群。也可以开发出一种人造信息素，引诱蝗虫至陷阱后将其消灭。
康乐还表示，蝗虫可能会发生基因变异，不会对4-乙烯基苯甲醚产生反应。这种蝗虫可以被释放到野外，建立“不能群居”的蝗虫种群。
莱斯利·沃斯哈尔是洛克菲勒大学神经遗传学和行为实验室的负责人。她表示，其中一个最令人兴奋的进展是，找到能阻断4-乙烯基苯甲醚接收的化学物质。
她在《自然》期刊上发表了一篇有关这项研究的文章，文中写道：这种分子的发现可以提供一种阻止蝗虫聚集成群的化学物质，“并使蝗虫‘解散’，回归它们平静和独居的生活方式。”
沃斯哈尔指出，目前仍有几个未知情况。包括4-乙烯基苯甲醚是否是导致蝗虫群形成的唯一原因，以及其他种类的蝗虫是否会对这一化合物作出类似反应。
布莱恩·林恩报道。
译文为可可英语翻译，未经授权请勿转载！
