经济学人:蜜蜂不喜健康植株爱病毒 意在帮宿主繁衍

 　　Science and technology: Evolution: Bee kind to viruses 科学技术：进化：蜜蜂爱病毒

　　A strange tale of collaboration¹ between plants, pathogens and insects. 植物、病毒和昆虫的奇特合作。

　　Cucumber mosaic² virus is not restricted to its eponymous host. 黄瓜花叶病毒能感染不是只有黄瓜。

　　They could also ravage³ tomatoes—stunting them and causing them to produce contorted tendril-like leaves. 这种病毒也荼毒番茄——病株会长出卷曲的病叶。

　　Given this devastation⁴, it is surprising susceptible⁵ plants continue to exist; natural selection should have produced resistance years ago. 考虑到病毒的危害，至今还存在易感染植物着实让人惊奇——自然选择应该早就帮助它们形成了病毒抵抗力。

　　A paper in this week’s PLoS Pathogens, however, explains the apparent contradiction. 本周，PLoS Pathogens发表的一篇论文解释了这一明显矛盾。

　　The team that wrote it, led by John Carr of Cambridge University, found that the virus actually helps its host to reproduce. 发表这篇文章的团队由剑桥大学的约翰·卡尔带领，他们发现病毒实际上在帮助宿主繁衍。

　　It does so using an unsuspecting accomplice⁶: the bumble-bee. 而达成这种目标借助的不是别的，正是大黄蜂。

　　Like many discoveries, this one was accidental. 像很多发现一样，这个发现也纯属偶然。

　　Dr Carr had ordered some equipment to analyse the volatile⁷ chemicals emitted by infected tomato plants. 卡尔博士订购了一些设备用来分析番茄病株释放的易挥发化学物质。

　　While he was waiting for it to arrive, a colleague offered to lend him some bees, as these pollinators are known for their sense of smell. 在等候交货的这段时间，一位同事提出借给他一些蜜蜂，因为这些传粉使者具有灵敏的嗅觉。

　　His team placed both healthy and infected plants in a greenhouse, covered them so that the bees could smell but not see them, and released the insects. 于是团队人员把正常植株和感染植株一同放到温室，遮盖它们确保蜜蜂只能嗅到而不能看到它们，然后释放蜜蜂。

　　The bees could indeed tell the difference—but to Dr Carr’s surprise they did not favour the healthy plants. 蜜蜂确实可以嗅出植株的不同，但令卡尔博士感到惊讶的是，它们并不喜欢健康植株。

　　Rather, they strongly preferred the infected ones. 相反，它们对感染植株青睐有加。

　　For some viral strains, they were four times more likely to visit an infected plant than a healthy one. 有一些受感染的病株甚至能吸引比健康植株多三倍的蜜蜂。

　　Subsequent experiments, carried out after the analytical⁸ apparatus⁹ had arrived, showed that this difference in behaviour was,  在分析设备到货以后进行的后续实验揭示了蜜蜂区别对待植株的原因

　　indeed, a response to differences in the chemicals that infected and uninfected plants give off. 感染植株和健康植株释放的化学物质不同。

　　The question was how the bees’ preference played into the plants’ evolution. 那么蜜蜂的偏爱在植物进化中起到了什么作用呢？

　　Tomatoes are able to fertilise themselves, without need of a pollinator, yet even this self-pollination can be assisted by a bee visiting a flower. 番茄可以自我繁衍，不需要传粉者，但是如果有蜜蜂来传播花粉，这种自花授粉的植物也会得到帮助。

　　Vibrations¹⁰ caused by the insect’s buzzing help release pollen¹¹ from the flower’s anthers so that it can fall onto the stigma¹². 昆虫翅膀的震动帮助播撒取自花药的花粉，并落到柱头上。

　　Could this process, Dr Carr wondered, make up for the evolutionary¹³ disadvantage the virus otherwise inflicts¹⁴? 卡尔博士疑惑这个过程能否弥补病毒在其他方面带来的进化劣势。

　　To investigate, he and his colleagues grew both healthy and infected tomatoes in a greenhouse with no bees,  为了进一步调查，卡尔博士和同事在一个温室里种植了健康番茄和感染番茄，但是没有蜜蜂，

　　and a similar mixture in a greenhouse into which bees were released one at a time, and their movements tracked. 又在另一个温室里进行同样的种植，但是向这个温室每次释放一只蜜蜂，并追踪它的轨迹。

　　They then analysed the seeds of the fruits of each plant as a proxy¹⁵ for evolutionary fitness. 之后他们选取每株番茄的种子作为进化适应性的代表进行分析。

　　All of the seeds they looked at seemed viable¹⁶. 他们观察的种子似乎都有望存活。

　　What differed was the number of seeds in each fruit. 不同点在于每个番茄果实内所含的种子数量。

　　In the bee-free greenhouse, infected plants had only about 50 seeds per fruit, whereas healthy ones averaged 70. 在没有蜜蜂的温室里，感染番茄平均每个果实仅含50枚种子，健康番茄70枚。

　　When bees were present, though, something strange happened. 在蜜蜂活动的温室里，神奇的事情上演了。

　　The seed count of fruits from healthy flowers visited by bees increased to 85—but that of the flowers of infected plants jumped much higher, to 115. 蜜蜂拜访过的健康番茄果实内的种子增长至85枚，而感染番茄跃升至115枚。

　　Further investigation¹⁷ showed a possible reason. 更深入的调查提供了可能的解释。

　　Not only did bees visit the infected plants more, but they also spent longer buzzing around infected flowers. 感染番茄不仅能吸引更多蜜蜂，还能让它们环绕感染植物飞舞更久。

　　The extra pollen thus displaced probably explains how the sickly plants outproduced their healthy confreres. 充裕的花粉很可能是这些生病植株比它们健康的同伴更高产的原因。

　　Using these experimental data, the researchers modelled how the system might have evolved. 研究人员运用实验数据模拟了这一系统可能的发展过程。

　　They found that the pollinator’s preference for the smell of infected plants was big enough to stop the emergence¹⁸ of viral-resistance in tomatoes. 他们发现，传粉者对感染植株味道的青睐足以阻止番茄形成病毒抵抗力。

　　That explains what is in it for the tomatoes and also for the virus. 这同样解释了番茄和病毒的利害关系。

　　What the bees get out of it, though, remains¹⁹ mysterious. 但是蜜蜂能从中分一杯什么羹，还是个谜。

1 collaboration   

n.合作，协作；勾结

参考例句：

• The two companies are working in close collaboration each other.这两家公司密切合作。
• He was shot for collaboration with the enemy.他因通敌而被枪毙了。

2 mosaic   

n./adj.镶嵌细工的，镶嵌工艺品的，嵌花式的

参考例句：

• The sky this morning is a mosaic of blue and white.今天早上的天空是幅蓝白相间的画面。
• The image mosaic is a troublesome work.图象镶嵌是个麻烦的工作。

3 ravage   

vt.使...荒废，破坏...；n.破坏，掠夺，荒废

参考例句：

• Just in time to watch a plague ravage his village.恰好目睹了瘟疫毁灭了他的村庄。
• For two decades the country has been ravaged by civil war and foreign intervention.20年来，这个国家一直被内战外侵所蹂躏。

4 devastation   

n.毁坏；荒废；极度震惊或悲伤

参考例句：

• The bomb caused widespread devastation. 炸弹造成大面积破坏。
• There was devastation on every side. 到处都是破坏的创伤。 来自《简明英汉词典》

5 susceptible   

adj.过敏的，敏感的；易动感情的，易受感动的

参考例句：

• Children are more susceptible than adults.孩子比成人易受感动。
• We are all susceptible to advertising.我们都易受广告的影响。

6 accomplice   

n.从犯，帮凶，同谋

参考例句：

• She was her husband's accomplice in murdering a rich old man.她是她丈夫谋杀一个老富翁的帮凶。
• He is suspected as an accomplice of the murder.他涉嫌为这次凶杀案的同谋。

7 volatile   

adj.反复无常的，挥发性的，稍纵即逝的，脾气火爆的；n.挥发性物质

参考例句：

• With the markets being so volatile,investments are at great risk.由于市场那么变化不定，投资冒着很大的风险。
• His character was weak and volatile.他这个人意志薄弱，喜怒无常。

8 analytical   

adj.分析的；用分析法的

参考例句：

• I have an analytical approach to every survey.对每项调查我都采用分析方法。
• As a result,analytical data obtained by analysts were often in disagreement.结果各个分析家所得的分析数据常常不一致。

9 apparatus   

n.装置，器械；器具，设备

参考例句：

• The school's audio apparatus includes films and records.学校的视听设备包括放映机和录音机。
• They had a very refined apparatus.他们有一套非常精良的设备。

10 vibrations   

n.摆动( vibration的名词复数 )；震动；感受；（偏离平衡位置的）一次性往复振动

参考例句：

• We could feel the vibrations from the trucks passing outside. 我们可以感到外面卡车经过时的颤动。
• I am drawn to that girl; I get good vibrations from her. 我被那女孩吸引住了，她使我产生良好的感觉。 来自《简明英汉词典》

11 pollen   

n.[植]花粉

参考例句：

• Hummingbirds have discovered that nectar and pollen are very nutritious.蜂鸟发现花蜜和花粉是很有营养的。
• He developed an allergy to pollen.他对花粉过敏。

12 stigma   

n.耻辱，污名；(花的)柱头

参考例句：

• Being an unmarried mother used to carry a social stigma.做未婚母亲在社会上曾是不光彩的事。
• The stigma of losing weighed heavily on the team.失败的耻辱让整个队伍压力沉重。

13 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

14 inflicts   

把…强加给，使承受，遭受( inflict的第三人称单数 )

参考例句：

• Bullfrog 50 Inflicts poison when your enemy damages you at short range. 牛娃50对近距离攻击你的敌人造成毒伤。
• The U.S. always inflicts its concept of human nature on other nations. 美国总是把自己的人权观念强加于别国。

15 proxy   

n.代理权，代表权；（对代理人的）委托书；代理人

参考例句：

• You may appoint a proxy to vote for you.你可以委托他人代你投票。
• We enclose a form of proxy for use at the Annual General Meeting.我们附上委任年度大会代表的表格。

16 viable   

adj.可行的，切实可行的，能活下去的

参考例句：

• The scheme is economically viable.这个计划从经济效益来看是可行的。
• The economy of the country is not viable.这个国家经济是难以维持的。

17 investigation   

n.调查，调查研究

参考例句：

• In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
• He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。

18 emergence   

n.浮现，显现，出现，（植物）突出体

参考例句：

• The last decade saw the emergence of a dynamic economy.最近10年见证了经济增长的姿态。
• Language emerges and develops with the emergence and development of society.语言是随着社会的产生而产生，随着社会的发展而发展的。

19 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。