雅思课外阅读材料：蚊子到底咬谁

Research reveals why some people are constantly under attack from the bloodsucking insects, while others walk free. 研究揭示了为什么有些人总是会受到吸血虫蚊子的袭击而有些人却可以平安无事。

For those unfortunate enough to feature highly on the mosquito hit list, summer nights are synonymous with mosquito bites. Yet others hardly ever get bitten. So how do the bloodthirsty insects select their victims?

对那些很不幸被蚊子列为叮咬对象的人们来说，夏夜就是蚊虫叮咬的代名词。而有些人却从没被蚊子叮咬过。那么这些吸血虫是如何选择它们的受害对象的呢?

Scientists rubbed petri dishes against their stomachs. The mosquito season gives rise to countless speculations about possible solutions to the age-old mystery of mosquito preferences.

科学家们把培养皿自己的腹部进行擦拭。对于关于蚊子喜好的可能性解释，蚊子的繁殖季节提供了无数的猜想。

The insects’ tastes may seem arbitrary. However, research reveals that when mosquitoes make their choice between potential victims, it all comes down to scent:

昆虫的口味好像很随意。然而研究显示当蚊子要从潜在的受害者中选择对象时，还是气味起了决定作用。

Mosquitoes are attracted by carbon dioxide and heat, which everyone gives off. But mosquitoes are also attracted by certain scents.Karl-Martin Vagn Jensen. According to Jensen, it has not yet been established exactly what the scents in question are. But research does indicate that some scents are more attractive to mosquitoes than others.

“蚊子会被每个人都会散发出的二氧化碳和热量所吸引，但蚊子也会被某些特定的气味所吸引。” 丹麦阿尔胡斯大学农学部研究的负责人卡尔马丁-威詹森说。根据他的说法，目前仍没确定那些会吸引蚊子的气味到底是哪些。但研究的确指出了有些气味相比较其它气味而言更会吸引蚊子。

“All the lab employees rubbed petri dishes against their stomachs. In that way, their scents were deposited on the dishes, which were then put in an enclosure full of mosquitoes,” he says.

“所有的实验室人员都把培养皿在他们的腹部轻轻擦了擦。通过这种方式，他们的气味就存储在了培养皿里，然后把培养皿放置在一个蚊子出没的地方。”

“The mosquitoes repeatedly landed on some of the petri dishes, but didn’t go anywhere near the others. “

“蚊子会反复地停留在某些培养皿上，却不会飞到附近其它的培养皿上。”

Vitamin B does not scare off mosquitoes. The experiment is one of several to squash one of the many myths concerning the unfortunate art of mosquito attraction.

维他命B并不能吓走蚊子。这个实验也戳穿了诸多关于吸引蚊子的“倒霉学问” 迷信。

While some believe that it is in fact sour blood that keeps the insects at bay, or that the mosquitoes can detect blood disease, others are convinced that vitamin B provides protection against mosquitoes.

有些研究人员认为血液的酸性环境让蚊虫无法存活，或是蚊子可以检测血液疾病，而另一些人相信维他命B提供了免于蚊虫叮咬的保护。

However, there is no indication that any of these theories are correct, says Jensen: “There is no truth to that. The theory about vitamin B has been tested very, very thoroughly, and it doesn’t hold.”

然而，没有证据表明这些理论都是正确的。詹森说：“关于这一点还没有任何存在的事实。关于维他命B的理论已经反反复复经过了论证，但这种说法似乎站不住脚。”

Perhaps taking inspiration from popular fiction, there are also those who swear by garlic as an excellent repellent against the winged bloodsuckers. According to the researcher, though unsubstantiated, this strategy may not be entirely fruitless:

也许可以从流行小说里得到一些启发，也有些人宣称大蒜是一种可以用来对付蚊子很好的防虫剂。据研究人员透露，尽管还未经证实，但这种方法也并非完全无效：

“As far as I know, there is no scientific proof that eating garlic works. But there may be something to the theory that it’s possible to mask your scent with garlic,” he says.

“就我所知，目前没有科学依据证明吃大蒜会有效预防蚊虫叮咬。但在理论上它也许是行得通的，可以用大蒜来掩盖你的气味。”詹森说。

The only reliable method of protection against mosquitoes is to use one of the effective repellents that are sold over the counter. Mosquito repellent contains some smells that confuse the mosquitoes. The first thing a mosquito does when looking for prey is to see if there are any animals or people in the vicinity.

唯一有效的免于蚊虫叮咬的方法是使用在柜台处买来的对付蚊虫的强效防蚊剂。防蚊剂包含了一些让蚊子产生混淆的气味。蚊子寻找猎物要做的第一件事是查看附近有没有动物和人。

“When the mosquito comes closer, it uses smell, heat and carbon dioxide to decide whether to bite. But if it is confused by a repellent, it will never get that far,” says Jensen. However, even repellents do not provide complete protection against the persistent insects.

“当蚊子靠近时，它会根据气味、热量和二氧化碳来决定是不是要叮咬。但如果它被防虫剂弄迷糊了，它不会轻率行动。”詹森说。然而，即使是防虫剂也没有为人们提供保护，让我们完全免于蚊虫频繁袭击。

“Repellents reduce the number of bites by as much as 70 percent. That’s all well and good, but you’ll still get bitten once in a while.”

“防虫剂可以减少蚊虫的叮咬次数，最多能降低70%。这样的效果也算很不错了，但你仍会时不时地被咬上一口。”