经济学人下载:昆虫学 有失蜂度

Science and technology
科学技术

Entomology
昆虫学

Bad beehaviour
有失蜂度

The strange case of the bandit bumblebees
熊蜂：不可思议的土匪

TO MOST people, bumblebees are charming, slightly absurd creatures that blunder through garden and meadow with neither the steely determination of the honeybee nor the malevolent intention of the wasp.
在人们的印象里，熊蜂可爱、友好而又有些令人可笑。它们跌跌撞撞地穿过花园和草场，既不像蜜蜂，有钢铁般的决心；也不似黄蜂，具备恶意的企图。

If you are a plant, though, things look rather different—for from the point of view of some flowering plants many bumblebees are nothing more than thieves.
不过，如果你是一株植物，你就会从新定义它们。从一些有花植物角度来看，熊蜂是彻头彻尾的贼：

They rob them of their nectar and give nothing in return.
它们掠夺花蜜，却未予回报。

Nectar robbery, in which a bumblebee carves a hole in the side of a flower as a bank robber might cut his way into a vault, was discovered by Charles Darwin.
某些花的形状发生了演化，以促进具有长舌的昆虫为其授粉。昆虫的长舌能探到狭小管道状花的深处。

This technique lets bees get at the nectar of flowers whose shapes have evolved to encourage their pollination by insects with long tongues, which can reach down narrow tubes.
达尔文最先发现熊蜂抢劫花蜜的行为。熊蜂在花的一侧切开一个口，行径无异于银行强盗杀进金库。它们凭借这种本领获取狭小管道状花的花蜜。

Some bumblebees do have such tongues. But some do not.
有的熊蜂的确有长舌，不过有些确实没有。

Short-tongued bees are, however, unwilling to deny themselves the bounty of nectar inside these flowers. Hence the hole-cutting.
短舌熊蜂难以抵御丰厚花蜜的诱惑，于是就有了切口打孔。

By breaking in in this way, though, a bumblebee nullifies the 100m-year-old pact between flowering plants and insects: that the plant feeds the insect in exchange for the insect pollinating the plant.
然而这种暴力获取的方式却撕毁了有花植物和昆虫间一亿万年的古老契约：植物为昆虫提供食物，昆虫履行为其授粉的义务。

The question about nectar robbery that has intrigued biologists from Darwin onwards is whether the behaviour is innate or learnt.
熊蜂抢劫花蜜的行为到底是先天性还是后天性，自达尔文起，生物学家们一直对此感到困惑。

Darwin, though he originated the idea that many behaviour patterns are products of evolution by natural selection, suspected that it is learnt.
达尔文推测这是后天性的。

Insects, in other words, can copy what other insects get up to.
换言之，他推测昆虫有能力模仿其他昆虫的行为习惯。

Only now, though, has somebody proved that this is true.
直到现在，这种推测才被证明是正确的。

The observations were made by David Goulson, and his colleagues.
做出观测的是David Goulson以及他的同事。

To test his ideas he had to go from Britain to Switzerland, for only there could he find a flower of the correct shape to conduct the study.
为了检验他的想法，他必须远离英国前往瑞士。因为只有那里才能找到形状合适的花以进行研究。

His crucial observation was that when the flowers of an alpine plant called the yellow rattle are robbed, the entry holes—because of the structure of the flower—tend to be unambiguously on either the right-hand side or the left-hand side.
决定性的观测在于yellow rattle被熊蜂造访后留下的孔。由于这种花的特殊结构，人们可以明确地区分出孔在花的左侧还是右侧。

Moreover, preliminary observation suggested that the holes in flowers in a single meadow are often all made on the same side.
加之初步观测结果表明，同一块草场中这种花上的孔常常在同一侧。

This led him to speculate that bumblebees in a particular area do indeed learn the art of nectar robbery from one another, and then copy the technique with such fidelity that they always attack a flower from the same side.
他认为，对于生活在所研究的特定草场中的熊蜂，它们确确实实从其他个体那里学习了抢劫花蜜的技术。并且它们模仿的相当精准，以至于总是从同一侧侵袭花朵。

Crime and nourishment
罪与馐

His team monitored 13 alpine meadows during the summers of 2009 and 2011.
他的研究组于2009年和2011年的夏天监测阿尔卑斯山13块草场。

They painstakingly recorded the sites of robbery holes in yellow-rattle flowers, and studied the behaviour of 168 bumblebees.
他们煞费苦心地记录yellow rattle上抢劫孔的位置，并且研究了168只熊蜂的行为。

They tried to follow each bee until it had visited 20 flowers, though they lost sight of some insects before they had reached this score.
研究组尽力追踪每只熊蜂，直到它光顾的花达到20朵为止。

If they could, they then captured the insect so as not to follow it again on another occasion.
尽管有些熊蜂没有达到这个数量就不见了，但若够数，他们旋即捉捕那只熊蜂，以防止二次追踪。

Dr Goulson found, as he reports in Behavioral Ecology and Sociobiology, that two short-tongued bumblebee species which live in the area, Bombus lucorum and Bombus wurflenii, demonstrated handedness when they robbed flowers.
博士发现，生活在该地区的两种短舌熊蜂在打劫花时表现出利手行为。

Moreover, if one species was behaving in a left-handed manner in a particular meadow, the other was likely to do the same.
更有甚者，如果针对特定的草场，一种熊蜂是左撇子，那么另一种熊蜂通常也是左撇子。

This suggests that one species can learn from another—a trick previously thought to be confined to vertebrates.
这暗示一物种可以向另一物种学习—过去人们认为只有脊椎动物才有这种本领。

Handedness in any given meadow, Dr Goulson found, increased as the season progressed.
他还发现，在任何指定的草场中，利手性随着季节的更替而强化，

But each summer appeared to start as a blank slate.
但每到夏天则似乎从新形成。

The handedness that developed in a meadow in 2009 did not predict its handedness in 2011.
某块草场中09年利手性并没有预测出11年的利手性。Goulson博士将以上发现发表在《生态学与社会生物学》上。

The most reasonable explanation, Dr Goulson argues, is that each year a few bumblebees which have learnt the trick of nectar robbery in the previous season come out of hibernation and start robbing flowers again.
Goulson博士认为最合理的解释是：每一年，一些熊蜂在过去季节里掌握了抢劫花蜜本领，它们冬眠后再次出来抢劫。

By chance, they make more holes on one side of the flowers than the other, and as the habit is picked up by other, newly hatched bees, a preference for left or right spreads by a process of positive feedback.
它们偶然间在花的一侧制造出更多的抢劫孔。由于其他新孵化出的熊蜂效仿了这种习惯，左利手或右利手作为一种正反馈进行传播。

The bees have, in other words, created a simple culture.
或者说，熊蜂创造出一种简单的文化。

It is a criminal culture, admittedly.
诚然，这是一种罪恶的文化，

But no one ever said that nature was pretty.
但没有人曾说，自然界原本是优雅的。