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？

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

“Mosquitoes are attracted by carbon dioxide and heat， which everyone gives off. But mosquitoes are also attracted by certain scents.” says Karl-Martin Vagn Jensen， head of the Department of Agriculture from Aarhus University， Denmark. 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.

“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.

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

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： There may be something to the theory that it’s possible to mask people’s scent with garlic.

The only reliable method of protection against mosquitoes is to use one of the effective repellents. 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.

“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.

“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.”

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。而有些人卻從未被蚊子叮咬過。那么這些吸血蟲是如何選擇它們的受害對象的呢？

蚊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。

“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?！钡湴柡勾髮W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，目前還無法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他氣味而言更會吸引蚊子。

“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)皿上，然后把培養(yǎng)皿放置在一個蚊子出沒的地方?！闭采f。

“蚊子會反復地停留在某些培養(yǎng)皿上，卻不會飛到附近其他的培養(yǎng)皿上?！?/p>

也許從流行小說里得到了一些啟發(fā)，也有些人宣稱大蒜是一種可以用來對付蚊子的很好的防蟲劑。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：在理論上它也許是行得通的，可以用大蒜來掩蓋人體的氣味。

唯一有效的免于蚊蟲叮咬的方法是使用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偵查附近有沒有動物和人。

“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。但如果它被防蚊劑弄迷糊了，就不會輕率行動?！闭采f。然而，即使是防蚊劑也沒能讓人們完全免于蚊蟲頻繁襲擊。

“防蚊劑可以減少蚊蟲的叮咬次數(shù)，最多能降低70%。這樣的效果算很不錯了，但你仍會時不時地被咬上一口?！?/p>