蜜蜂上哪里去了(2)【沪江慢速VOA 4-14】
Disappearance of Honey Bees a Mystery (2/2)
Mister Rexroad said the cause of the sudden loss of bees is not clear. The number of honey bees already had fallen before the colony collapse disorder began.
Experts say the varroa mite is at least partly responsible for the earlier decrease in honeybees. The mite is a tiny creature that feeds on honeybees. It may play a part in colony collapse disorder by carrying bee viruses. Or the problem may be caused by other diseases and weather conditions.
A group of scientists is examining bees from more than 100 colonies across the country. The researchers also are studying the pollen, honey, and wax that the bees produce. They are working with the Agriculture Department's Agricultural Research Service.
Diana Cox-Foster of Pennsylvania State University is part of the scientific group. Miz Cox-Foster says the nation needs honeybees that can defend themselves better against disease and insects. The recent mapping of most of the honeybee's genes offers hope of a stronger honeybee some day.
