Passage 16
When honey bees began to desert their hives recently，never to return，it threw apiarists into a panic.What appeared to be perfectly healthy adult bees would flee their queen，the young and their food stores.Instead of ransacking the empty hive，other bees would avoid it like the plague.Yet there was nothing obviously wrong.Researchers have now identified the first tangible clue in the mystery—a relatively new virus.
Colony collapse disorder became widespread in America in the winter of 2006-2007，when about a quarter of the nation’s beekeepers were affected，each losing between 30% and 90%of their winged workers.Bees are valued not so much for their honey，which is worth some$200m a year in America，but for their work in pollinating crops.This brings the economy some$15 billion a year，as apiarists move their hives to land producing fruit，vegetables and nuts.
Finding exactly why colonies collapse has been taxing the minds of both federal and university scientists.There have been few bodies on which to conduct autopsies.Those adult bees that have been found dead near an abandoned hive have been riddled with almost every bee disease known to man.Now a report by Diana Cox-Foster of Pennsylvania State University and her colleagues，published in the September 6th issue of Science，points the finger at the Israeli acute paralysis virus.The lurgy in question was，the researchers suggest，imported from Australia.
Because many factors could be acting together to cause bee colonies to collapse，Dr.Cox-Foster and her colleagues decided to examine everything they could find within the empty hives.They collected samples from infected hives and compared them not only with samples from apparently healthy hives but also with an analysis of royal jelly—a bee secretion fed to the larvae—from China，which has not been affected by the mystery disorder.From their samples，the researchers extracted RNA—a chemical that carries and helps to decode genetic0 information.Their analysis revealed the presence of various bacteria，fungi and viruses that were lurking in the hives and the royal jelly.They then looked to see whether there was anything in the abandoned hives that was not found elsewhere.
What they found was a virus first identified in 2004 in the Middle East.Bees infected with Israeli acute paralysis virus shiver，their bodies become frozen and they die.But the virus itself cannot be the sole cause of colony collapse disorder.For a start，all the hives infected with it were also infested with a second nasty，the Kashmiri bee virus.Yet this virus was also present in many of the apparently healthy hives.Intriguingly，there was also a virus that the researchers were unable to classify.They suspect it may be a new lineage of the Kashmiri bee virus，but it could be something completely novel.This second virus was also found only in the abandoned hives.
The researchers reckon that the reason why so many honey bees are dying is down to a combination of factors that are found only，so far，in America.The Israeli acute paralysis virus may have had such a devastating effect there because of the presence of a parasite called the varroa mite.This parasite weakens the immune systems of bees，making the consequences of an infection more likely to be fatal.Tellingly，bees in Australia have not been infected by the parasite.
1.When honey bees desert their hives，the other bees will usually____.
A.stay far away from the empty hives because they are useless
B.flee their queen，the young and their food stores away and steal the hives
C.throw apiarists into a panic by plaguing the empty hives
D.plunder the empty hives and take possession of all that is worth anything
2.When the bee colony collapse disorder became rampant in America，____.
A.the workers of the nation’s beekeepers resigned from the beekeeping factory
B.the apiarists moved their hives to land producing fruit，vegetables and nuts
C.the crops could not grow to maturity as before for short of effective pollination(https://www.daowen.com)
D.each apiarist suffered a loss of$200m to$1b a year as well as most of their workers
3.It has been a headache to find out why bee colonies collapse because of the following reasons EXCEPT____.
A.RNA experiment shows an intricate connection between the dead bees with their Chinese counterparts
B.dead bees near a deserted hive are found to carry too many diseases
C.there were almost no samples for scientists to do research on the dead bees
D.the scientists could not identify exactly which disease was the main factor that had caused the colonies collapse
4.Which one of the following statements is NOT true of the experiment carried out by Dr.Cox-Foster and her colleagues？
A.They collected samples not only from infected hives，but also from healthy hives and royal jelly.
B.They sorted out a chemical that provides relevant information from the genetic perspective.
C.The research points out that an Israeli virus is the main cause of the collapse disorder since the virus was found in the hives and the royal jelly.
D.They found that there were all kinds of viruses in the royal jelly which were also present in the infected hives.
5.According to the researchers，so many honey bees are dying probably because of the following reasons EXCEPT____.
A.the bees were affected with Israeli acute paralysis virus which was fatal to them
B.the hives were infected with a combination of the viruses that led to massive deaths of the bees
C.an unidentified virus which may be a new lineage of the Kashmiri bee virus or a new virus causes the disaster
D.the varroa mite is believed to worsen the conditions of the infected bees and leave them more vulnerable to deadly disease