雅思閱讀：蚊子如何選擇叮咬對象？

Research reveals why some people are constantly under attack from the bloodsucking insects, while others walk free.

研究揭示了為什么有些人總是會受到吸血蟲蚊子的襲擊而有些人卻可以平安無事。

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?

對那些很不幸被蚊子列為叮咬對象的人們來說，夏夜就是蚊蟲叮咬的代名詞。而有些人卻從沒被蚊子叮咬過。那么這些吸血蟲是怎樣選擇它們的受害對象的呢?

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.

科學家們把培養(yǎng)皿在自己的腹部進行擦拭。對于關于蚊子喜好的可能性解釋，蚊子的繁殖季節(jié)提供了無數(shù)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:

昆蟲的口味好像很隨意。然而研究顯示當蚊子要從潛在的受害者中選擇對象時，還是氣味起了決定作用。

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.

“蚊子會被每個人都會散發(fā)出的二氧化碳和熱量所吸引，但蚊子也會被某些特定的氣味所吸引。” 丹麥阿爾胡斯大學農(nóng)學部研究的負責人卡爾馬丁-威詹森說。根據(jù)他的說法，目前仍沒確定那些會吸引蚊子的氣味到底是哪些。但研究的確指出了有些氣味相比較其它氣味而言更會吸引蚊子。

“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.

“所有的實驗室人員都把培養(yǎng)皿在他們的腹部輕輕擦了擦。通過這種方式，他們的氣味就存儲在了培養(yǎng)皿里，然后把培養(yǎng)皿放置在一個蚊子出沒的地方。”

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

“蚊子會反復地停留在某些培養(yǎng)皿上，卻不會飛到附近其它的培養(yǎng)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.

維他命B并不能嚇走蚊子。這個實驗也戳穿了諸多關于吸引蚊子的“倒霉學問” 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.

有些研究人員認為血液的酸性環(huán)境讓蚊蟲無法存活，或是蚊子可以檢測血液疾病，而另一些人相信維他命B提供了免于蚊蟲叮咬的保護。

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，沒有證據(jù)表明這些理論都是正確的。詹森說：“關于這一點還沒有任何存在的事實。關于維他命B的理論已經(jīng)反反復復經(jīng)過了論證，但這種說法似乎站不住腳。”

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:

也許可以從流行小說里得到一些啟發(fā)，也有些人宣稱大蒜是一種可以用來對付蚊子很好的防蟲劑。據(jù)研究人員透露，盡管還未經(jīng)證實，但這種方法也并非完全無效：

“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，目前沒有科學依據(jù)證明吃大蒜會有效預防蚊蟲叮咬。但在理論上它也許是行得通的，可以用大蒜來掩蓋你的氣味。”詹森說。

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.

唯一有效的免于蚊蟲叮咬的方法是使用在柜臺處買來的對付蚊蟲的強效防蚊劑。防蚊劑包含了一些讓蚊子產(chǎn)生混淆的氣味。蚊子尋找獵物要做的第一件事是查看附近有沒有動物和人。

“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.

“當蚊子靠近時，它會根據(jù)氣味、熱量和二氧化碳來決定是不是要叮咬。但如果它被防蟲劑弄迷糊了，它不會輕率行動。”詹森說。然而，即使是防蟲劑也沒有為人們提供保護，讓我們完全免于蚊蟲頻繁襲擊。

“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.”

“防蟲劑可以減少蚊蟲的叮咬次數(shù)，最多能降低70%。這樣的效果也算很不錯了，但你仍會時不時地被咬上一口。”