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Mosquitoes Learn the Smell of Danger

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 robins¹, but will settle for mammals once the birds head south for the winter.

当说到吸血时，蚊子会喜欢它们：它们表现出对特定物种甚至特定个体的偏好。同时，根据具体情况，他们的口味可能会改变。例如，加利福尼亚州的一个物种，在夏季喜欢知更鸟，但是一旦鸟儿在南方过冬，它们就会成为哺乳动物。

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 scent² of their preferred host, they can use these olfactory³ cues to avoid individuals who try to swat them. The finding is in the journal Current Biology.

但现在蚊子如何决定菜单上的内容?何时转向新事物?看起来他们是通过鼻子和他们预期的受害者的行为来玩的。因为一项新的研究结果表明，蚊子不仅能够记住他们喜欢的寄主的气味，还可以使用这些嗅觉线索，来避免试图扑杀它们的人。这一研究结果发表在《当代生物学 》杂志上。

Researchers took female mosquitoes of the species Aedes aegypti and loaded them one by one into a maze⁴ shaped like a Y. One arm of the Y was suffused⁵ 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.

研究人员将埃及雌性蚊子逐个装入Y形的迷宫中。Y的一只手臂充满了人类志愿者的气味。 另一个包含矿物油的对照溶液。正如预测的那样，蚊子表现出对欧洲智人的明显偏好。

Next, the researchers attempted to train the mosquitoes to flee from the heady aroma⁶ of humans. So they coupled the exposure to human odor with a mechanical vibration—something akin⁷ 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 defensive⁸ maneuvers⁹ lost their appetite for the previously¹⁰ attractive scent.

接下来，研究人员试图训练蚊子逃离人类的狂喜香气。因此，他们将机械震动与人体气味相结合——类似于可能伴随着主人不知所措的震动。果然，经过训练将人类气味与其潜在的致命防御机动相结合的蚊子，失去了对以前吸引人气味的胃口。

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.So the researchers used an array of molecular¹¹ 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.

研究人员发现，这种学习可以通过神经递质多巴胺来实现。这种生物化学物质以前曾被证明，在雌性蚊子寻求吸吮时起作用。它涉及到其他昆虫的学习和记忆。因此，研究人员使用了一系列分子技术，来去除埃及人感知和响应多巴胺的能力。没有这种神经递质，蚊子在学习时变得更加糟糕。

Targeting mosquitoes’ smarts could thus provide a new method for curbing¹² the spread of diseases carried by Aedis aegypti—like Zika, dengue, and yellow fever. Because mosquitoes that are slow learners are easier to swat.

因此，针对蚊子的智慧，可以提供一种新的方法，来遏制埃迪氏菌埃卡样病毒、登革热和黄热病携带的疾病的传播。因为学习速度慢的蚊子<扑打/拍击噪音>更容易扑打了。