Scientists discover clues for vanishing bee colonies

A virus found in healthy Australian honey bees may be playing a role in the collapse of honey bee colonies across the United States. Colony collapse disorder has killed millions of bees — up to 90 percent of colonies in some U.S. beekeeping operations — imperiling the crops largely dependent upon bees for pollination, such as oranges, blueberries, apples, and almonds. The U.S. Department of Agriculture says honey bees are responsible for pollinating $15 billion worth of crops each year in the United States. More than ninety fruits and vegetables worldwide depend on them for pollination. Signs of colony collapse disorder were first reported in the United States in 2004, the same year American beekeepers started importing bees from Australia. The disorder is marked by hives left with a queen, a few newly hatched adults and plenty of food, but the worker bees responsible for pollination gone.

CNN reports that the virus identified in the healthy Australian bees is Israeli Acute Paralysis Virus (IAPV), so named because it was discovered by Hebrew University researchers. Worker bees in colony collapse disorder vanish, but bees infected with IAPV die close to the hive, after developing shivering wings and paralysis. For some reason the Australian bees seem to be resistant to IAPV and do not come down with symptoms. Scientists used genetic analyses of bees collected over the past three years and found that IAPV was present in bees that had come from colony collapse disorder hives 96 percent of the time. the study released Thursday on the ScienceExpress Web site, operated by the journal Science, cautioned that collapse disorder is likely caused by several factors.

Bee ecology expert and University of Florida professor Jamie Ellis said earlier this year that genetic weakness bred into bees over time, pathogens spread by parasites and the effects of pesticides and pollutants might be other factors. Researchers also say varroa mites affect all hives on the U.S. mainland but are not found in Australia. University of Georgia bee researcher Keith Delaplane said Thursday the study offers a warning — and hope. “One nagging problem has been a general inability to treat or vaccinate bees against viruses of any kind,” said Delaplane, who has been trying to breed bees resistant to the varroa mite. “But in the case of IAPV, there is evidence that some bees carry genetic resistance to the disorder. This is yet one more argument for beekeepers to use honey bee stocks that are genetically disease- and pest-resistant.” Bee researchers will now look for stresses that may combine to kill bees. “The next step is to ascertain whether IAPV, alone or in concert with other factors, can induce CCD [colony collapse disorder] in healthy bees,” said Ian Lipkin, director of the Center for Infection and Immunity at Columbia University Mailman School of Public Health.

-read more in Diana L. Cox-Foster et al., “A Metagenomic Survey of Microbes in Honey Bee Colony Collapse Disorder,” ScienceExpress (6 September 2007): 1-7 (10.1126/science.1146498( (sub. req.)