The secret death of bees

Researchers are a step closer to solving the mystery of the disappearing honeybees, according to a paper published this week in the journal Science. Scientists had dubbed the strange syndrome colony collapse disorder, or CCD. Beekeepers across the country reported finding their hives empty and the worker bees missing. Vexed, researchers started exploring a number of possible causes for CCD, including pesticide use, parasites and the prevalence of multiple stresses, such as overcrowding, frequent travel from one field to another or a contaminated water supply. Other fingers were pointing at causes as disparate as global warming and the increase in the number of cellphone towers. No common environmental factor could be identified.

The phenomenon was widespread, however. U.S. commercial beekeepers, many of whom move their apiaries to different farms selling the honeybees’ pollination service, reported an average loss of nearly 40 percent of their managed colonies between September 2006 and March. Beekeepers in Georgia, Michigan and Pennsylvania reported losses of more than 50 percent, while their colleagues in Ohio saw more than 70 percent disappear.

Part of what made this so difficult to understand, and such a mystery, was that the bees literally disappeared, and beekeepers and farmers couldn’t turn up an appreciable number of carcasses for analysis. The honeybees presumably died in the fields, either lost or unable to return to the hive.

While this posed an intriguing scientific question, it also presented a serious and pressing economic concern. The essential role that honeybees play in pollinating fruits, vegetables and other crops can’t be easily duplicated. The honeybee contribution to U.S. agriculture is worth roughly $15 billion per year.

Genetic sequencing of healthy and infected samples allowed scientists to isolate and compare the bacteria, viruses and fungi present in honeybees. One virus was identified as common to the infected but not the healthy bees. Called the Israeli acute paralytic virus because it was first identified three years ago in Israel, it was likely imported with bees from Australia in 2004 and is known to paralyze bees, usually away from the hive.

The syndrome is far from being fully understood. The virus identified by researchers may be causing CCD, or it may be a symptom of something else that is really causing honeybees to vanish. Either way, this is an important step toward solving that urgent mystery. Additional research will undoubtedly shed more light on the mystery.