Bees pollinate many of the world 's crops-a service estimated to be worth $ 15 billion a year in america alone .
它们负责为许多农作物传粉,据估计这项工作仅在美国就能创造出每年150亿美元的产值。
Since they 're often forced to pollinate one specific crop , they may not get all the nutrients they need to be healthy .
因为它们经常会被迫向一种单一的作物传粉,所以它们可能无法摄入维持健康所需的所有营养。
Much like how the primary function of petals on a flower is to attract insects to pollinate , good design ensures that your website will thrive .
就像花瓣的主要作用是吸引昆虫授粉一样,好的设计能够促使网站壮大。
If it 's a parasite , it needs a host ; if it 's a plant , it may need bacteria to help it process nitrogen or bees to pollinate its flowers .
如果是寄生虫,它就需要宿主;如果是植物,它可能就需要细菌来帮助它合成氮或者需要蜜蜂来给花授粉。
They are putting forward the theory that radiation given off by mobile phones and other hi-tech gadgets is a possible answer to one of the more bizarre mysteries ever to happen in the natural world - the abrupt disappearance of the bees that pollinate crops .
Beekeeping is one example beloved by economic theorists . Bees create honey , which can be sold on the market . But they also pollinate nearby apple trees , a useful service that is not purchased or priced .
Since one species of italian honey bee , apis mellifera , was conscripted to pollinate foods , cotton , alfalfa and clover for the beef and dairy industries 150 years ago , it has helped to generate more than 200 billion per year worldwide .