英語聽力文摘585 不同年齡的蜜蜂有不同的分工！

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.