The bloodsuckers lose their appetite for attractive scents when they associate those aromas with a likelihood of being swatted.
当“吸血狂魔”面临可能被打死的危险时，它们会失去对吸引它们的香味的感知能力。
播音\撰文：Karen Hopkin
翻译：张艺箫
校对：张清越
When it comes to sucking blood, mosquitos can play favorites: they show preferences for particular species or even certain individuals. At the same time, their tastes can change, depending on the circumstances. One species of skeeter in California, for example, has a fondness in summer for robins, but will settle for mammals once the birds head south for the winter.
当提到吸血两个字时，我们很容易想到蚊子这种昆虫：它们会对特定的物种甚至某个个体表现出偏爱。与此同时，它们的口味会在不同的环境下发生改变。例如，加利福尼亚州的一种蚊子在夏天的时候十分偏爱更知鸟，但是到了更知鸟南迁的冬天，它们就会把哺乳动物当作吸血目标。
But how do mosquitoes decide what’s on the menu? And when to shift to something new? It appears that they play it by nose—and by their intended victim’s behavior. Because a new study shows that mosquitoes not only memorize the scent of their preferred host, they can use these olfactory cues to avoid individuals who try to swat them. The finding is in the journal Current Biology. [Clément Vinauger et al., Modulation of Host Learning in Aedes aegypti Mosquitoes]
但蚊子是怎样决定自己菜单上有什么的？怎样决定什么时间换成新的菜式？这看起来像是它们用鼻子——以及 “目标食物”的行为表现来做的决定。一项新的研究表明蚊子不仅记得他们喜欢的“食物”的气味，它们还会用自己的嗅觉器官来避开会攻击它们的对象。这项研究结果发表在《Current Biology》杂志上。
Researchers took female mosquitoes of the species Aedes aegypti and loaded them one by one into a maze shaped like a Y. One arm of the Y was suffused with the scent of a human volunteer. The other contained a control solution of mineral oil. As predicted, the mosquitoes showed an obvious preference for eu d’ Homo sapiens.
研究人员把雌性埃及伊蚊一个一个地装到一个Y形迷宫中。Y的一边弥漫这一个人类志愿者的气味。而另一边放的是矿物油的校核液。和预想的一样，蚊子对智人的气味表现出明显的偏爱。
Next, the researchers attempted to train the mosquitoes to flee from the heady aroma of humans. So they coupled the exposure to human with a mechanical vibration—something akin to the shock that might accompany a near-miss by a swatting host. Sure enough, mosquitoes that were trained to associate human smells with their potentially deadly defensive maneuvers lost their appetite for the previously attractive scent.
接下来，研究人员尝试训练蚊子离开那另它们陶醉的人类的气味。他们将机械振动（类似一个与它们擦肩而过的拍打动作产生的效果）与人的气味相结合。很快，被训练出把人类气味与死亡威胁联系起来的蚊子，已经失去了对先前吸引它们的气味（人类的气味）的兴趣。
That learning, the researchers found, is made possible by the neurotransmitter dopamine. This biological chemical has previously been shown to play a role when female mosquitoes seek someone to suck. And it’s involved in learning and memory in other insects.
研究人员发现，这种学习成果是神经递质多巴胺带来的。以往研究表明，这种生化物质在雌性蚊子寻找吸血对象起着重要作用，且与其他昆虫的学习和记忆能力也有联系。
So the researchers used an array of molecular techniques to knock out the aegypti’s ability to sense and respond to dopamine. And without this neurotransmitter, mosquitoes become much worse at learning to avoid danger.
于是研究人员运用不同的分子技术来干扰蚊子对多巴胺的感知和反应能力。结果发现，如果没有多巴胺这种神经递质，蚊子躲避危险的能力就没有这么强。
Targeting mosquitoes’ smarts could thus provide a new method for curbing the spread of diseases carried by Aedis aegypti—like Zika, dengue, and yellow fever. Because mosquitoes that are slow learners
蚊子的智慧为我们研究抑制寨卡病毒、登革热和黄热病等蚊虫传染病的方法提供了新思路。因为一旦蚊子的学习能力降低了，它们就更容易被打死啦。
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