科学美国人60秒：蚊子能识别危险气味
燕山大学 刘立军 编写
TRANSCRIPT
This is Scientific American - 60-Second Science. I'm Karen Hopkin.
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.
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.
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.
Next, the researchers attempted to train the mosquitoes to flee from the heady aroma of humans. So they coupled the exposure to human odor 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.
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 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.
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 (swatting/slap noise) are easier to swat.
Thanks for listening for Scientific American - 60-Second Science. I'm Karen Hopkin.
Adapted from http://www.kekenet.com/broadcast/201808/560139.shtml
VOCABULARY
1. skeeter n. (North Amercian English, informal, humorous) = mosquito 蚊子
2. robin n. a grey American bird with a red breast, larger than a European robin 旅鸫，美洲知更鸟（毛灰色，胸部红色，比欧亚鸲大）
3. mammal n. any animal that gives birth to live babies, not eggs, and feeds its young on milk. Cows, humans and whales are all mammals. 哺乳动物
4. olfactory adj. (technical 术语) connected with the sense of smell 嗅觉的。例如：
olfactory cells / nerves / organs嗅觉细胞 / 神经 / 器官
5. swat v. to hit sth., especially an insect, using your hand or a flat object 拍，打（昆虫等）
6. maze n. a system of paths separated by walls or hedges built in a park or garden, that is designed so that it is difficult to find your way through 迷宫。例如：We got lost in the maze. 我们在迷宫里迷失了方向。
7. suffuse v. suffuse sb./sth. (with sth.) (literary) (especially of a colour, light or feeling 尤指颜色、光线或感情) to spread all over or through sb. / sth. 布满；弥漫于；充满。例如：Her face was suffused with colour. 她满脸通红。
8. aroma n. a pleasant, noticeable smell 芳香；香味。例如：the aroma of fresh coffee新鲜咖啡的香味
9. akin to sth.: (formal) similar to 相似的；类似的。例如：What he felt was more akin to pity than love. 他感受到的更像怜悯，而不是爱。
10. maneuver n. 策略
11. neurotransmitter n. (biology 生) a chemical that carries messages from nerve cells to other nerve cells or muscles 神经递质（在神经细胞间或向肌肉传递信息）
12. dopamine n. a chemical produced by nerve cells which has an effect on other cells 多巴胺（神经细胞产生的一种作用于其他细胞的化学物质）
13. molecular adj. 分子的
14. curb v. to control or limit sth., especially sth. bad 控制，抑制，限定，约束（不好的事物）。例如：
He needs to learn to curb his temper. 他得学着控制自己的脾气。
A range of policies have been introduced aimed at curbing inflation. 为了抑制通货膨胀实施了一系列的政策。
15. dengue n. a disease caused by a virus carried by mosquitoes , that is found in tropical areas and causes fever and severe pain in the joints 登革热（由蚊子传播的热带疾病，症状为发烧和关节剧痛）
QUESTIONS
Read the statements. Then listen to the news and fill in the blanks with the information (words, phrases or sentences) you hear.
1. When it comes to sucking blood, mosquitos can play favorites: they show preferences for (Q1) ____________________________ or even (Q2) _____________________. At the same time, their (Q3) ______________ can change, depending on the (Q4) __________________.
2. But how do mosquitoes decide what's on the menu? And when to shift to something new? It appears that they play it by (Q5) ____________ - and by (Q6) __________________________. Because a new study shows that mosquitoes not only memorize the (Q7) ___________ of their preferred host, they can use these olfactory cues to avoid (Q8) ________ who try to (Q9) ______ them. The finding is in the journal Current Biology.
3. Researchers took (Q10) ______________ 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 (Q11) _____________________ volunteer. The other contained a control solution of (Q12) _____________________. As predicted, the mosquitoes showed (Q13) ____________________ for eu d' Homo sapiens.
4. Next, the researchers attempted to train the mosquitoes to (Q14) _______________ the heady aroma of humans. So they coupled the exposure to (Q15) _________________ 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 (Q16) ________________ for the previously attractive scent.
5. 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 (Q17) __________________________ in other insects.
6. 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 (Q18) ___________________________.
7. Targeting mosquitoes' smarts could thus provide a new method for (Q19) __________________________________ carried by Aedis aegypti - like Zika, dengue, and yellow fever. Because mosquitoes that are (Q20) ____________________ (swatting/slap noise) are easier to swat.
KEY
Read the statements. Then listen to the news and fill in the blanks with the information (words, phrases or sentences) you hear.
1. When it comes to sucking blood, mosquitos can play favorites: they show preferences for (Q1) particular species or even (Q2) certain individuals. At the same time, their (Q3) tastes can change, depending on the (Q4) circumstances.
2. But how do mosquitoes decide what's on the menu? And when to shift to something new? It appears that they play it by (Q5) nose - and by (Q6) their intended victim's behavior. Because a new study shows that mosquitoes not only memorize the (Q7) scent of their preferred host, they can use these olfactory cues to avoid (Q8) individuals who try to (Q9) swat them. The finding is in the journal Current Biology.
3. Researchers took (Q10) 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 (Q11) human volunteer. The other contained a control solution of (Q12) mineral oil. As predicted, the mosquitoes showed (Q13) an obvious preference for eu d' Homo sapiens.
4. Next, the researchers attempted to train the mosquitoes to (Q14) flee from the heady aroma of humans. So they coupled the exposure to (Q15) human odor 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 (Q16) appetite for the previously attractive scent.
5. 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 (Q17) learning and memory in other insects.
6. 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 (Q18) avoid danger.
7. Targeting mosquitoes' smarts could thus provide a new method for (Q19) curbing the spread of diseases carried by Aedis aegypti - like Zika, dengue, and yellow fever. Because mosquitoes that are (Q20) slow learners (swatting/slap noise) are easier to swat.