英語聽力文摘585 不同年齡的蜜蜂有不同的分工！
- 聽力原文
- 參考譯文
Bees Have Different Jobs According To Their Age
Bees take on different jobs in a bee hive according to their age. Many become food scouts 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 decided to put that question to the test. They placed a hive in an enclosure 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 genes 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 novelty 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.
不同年齡的蜜蜂有不同的分工
不同年齡的蜜蜂在蜂群中有不同的分工。許多蜜蜂在年老時會充當“食物偵察兵”。但不是所有的“偵察兵”均如此。一些會去尋找新的花朵，其他的則往返于筑好的蜜源和蜂巢之間。
一組科學家想知道一些蜜蜂是否天生就擔當承擔風險的角色，于是決定通過實驗來找出答案。他們把蜂巢移到一個柵欄中，柵欄邊放置裝滿糖水的喂食器，然后把每個去過喂食器的蜜蜂都做上標記。
幾天過后，科學家們又安置了第二個喂食器，并標記出拜訪過的蜜蜂。為了給蜜蜂增加點難度，他們把第二個喂食器移動到一個新的位置，然后標記上發(fā)現新位置的蜜蜂。
兩次都能找到喂食器的叫做尋蜜蜂，而只在原先喂食器取蜜的蜜蜂稱之為保育蜂。尋找新蜂巢的筑巢蜂在年老時有三倍的可能性會成為尋蜜蜂。
為了確定尋蜜蜂和保育蜂之間是否存在不同，研究人員通過觀察它們的大腦來找出活躍的基因。他們的發(fā)現令人出乎意料。蜜蜂的上千種基因各不相同。有些基因與人類尋找新奇事物行為相關的基因十分相似。
科學家檢查了控制多巴胺信號的基因，這種基因會增強人類的愉悅感。但是在蜜蜂中該基因的作用卻恰恰相反;多巴胺含量高會增加蜜蜂的嫌惡感。攜帶這種能夠產生較多多巴胺感受器基因的蜜蜂叫做保育蜂，而那些產生較少感受器的蜜蜂就成為了尋蜜蜂。
