英语听力文摘 English Digest 585、不同年龄的蜜蜂有不同的分工！

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　　Bees take on different jobs in a bee hive according to their age. Many become food scouts¹ when older, but not all scouts are the same. Some search for new flowers, while others fly to and from established nectar sources.

 

　　A team of scientists wondering if some bees might be natural risk takers decided² to put that question to the test. They placed a hive in an enclosure³ with a feeder of sugar water and marked each bee that visited the feeder.

 

　　A few days later, they added second feeder and marked the bees that found that one. Challenging the bees again, they moved the second feeder to a new location and marked the bees that discovered that location too.

 

　　Bees that found new feeders both times were called scouts, while bees that only gathered nectar at the old feeder were called non scouts. Nest scouts, who search for new hive locations, were three times more likely to be nectar scouts when older.

 

　　To determine if there are differences between scouts and non scouts, researchers examined their brains to see which genes⁴ were active. What they found was surprising. There were large differences in over one thousand genes. Some of those genes are very similar to ones associated with human novelty⁵ seeking behavior.

 

　　Scientists examined genes controlling dopamine signaling, which reinforces pleasure in humans. In bees it works just the opposite; high dopamine reinforces aversion. Bees with genes that made more dopamine receptors were non scouts, while those with low receptors tended to be scouts.

 

 

 

　　不同年龄的蜜蜂有不同的分工

 

　　不同年龄的蜜蜂在蜂群中有不同的分工。许多蜜蜂在年老时会充当“食物侦察兵”。但不是所有的“侦察兵”均如此。一些会去寻找新的花朵，其他的则往返于筑好的蜜源和蜂巢之间。

 

　　一组科学家想知道一些蜜蜂是否天生就担当承担风险的角色，于是决定通过实验来找出答案。他们把蜂巢移到一个栅栏中，栅栏边放置装满糖水的喂食器，然后把每个去过喂食器的蜜蜂都做上标记。

 

　　几天过后，科学家们又安置了第二个喂食器，并标记出拜访过的蜜蜂。为了给蜜蜂增加点难度，他们把第二个喂食器移动到一个新的位置，然后标记上发现新位置的蜜蜂。

 

　　两次都能找到喂食器的叫做寻蜜蜂，而只在原先喂食器取蜜的蜜蜂称之为保育蜂。寻找新蜂巢的筑巢蜂在年老时有三倍的可能性会成为寻蜜蜂。

 

　　为了确定寻蜜蜂和保育蜂之间是否存在不同，研究人员通过观察它们的大脑来找出活跃的基因。他们的发现令人出乎意料。蜜蜂的上千种基因各不相同。有些基因与人类寻找新奇事物行为相关的基因十分相似。

 

　　科学家检查了控制多巴胺信号的基因，这种基因会增强人类的愉悦感。但是在蜜蜂中该基因的作用却恰恰相反；多巴胺含量高会增加蜜蜂的嫌恶感。携带这种能够产生较多多巴胺感受器基因的蜜蜂叫做保育蜂，而那些产生较少感受器的蜜蜂就成为了寻蜜蜂。

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