Honeybees don’t just make honey; they pollinate more than 90 of the tastiest flowering crops we have. Among them: apples, nuts, avocados, soybeans, asparagus, broccoli, celery, squash and cucumbers. And lots of the really sweet and tart stuff, too, including citrus fruit, peaches, kiwi, cherries, blueberries, cranberries, strawberries, cantaloupe and other melons.
In fact, about one-third of the human diet comes from insect-pollinated plants, and the honeybee is responsible for 80 percent of that pollination, according to the U.S.
Department of Agriculture.
Even cattle, which feed on alfalfa, depend on bees. So if the collapse worsens, we could end up being “stuck with grains and water,” said Kevin Hackett, the national program leader for USDA’s bee and pollination program.
“This is the biggest general threat to our food supply,” Hackett said.
While not all scientists foresee a food crisis, noting that large-scale bee die-offs have happened before, this one seems particularly baffling and alarming.
U.S. beekeepers in the past few months have lost one-quarter of their colonies — or about five times the normal winter losses — because of what scientists have dubbed Colony Collapse Disorder. The problem started in November and seems to have spread to 27 states, with similar collapses reported in Brazil, Canada and parts of Europe.
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The top suspects are a parasite, an unknown virus, some kind of bacteria, pesticides, or a one-two combination of the top four, with one weakening the honeybee and the second killing it.
A quick experiment with some of the devastated hives makes pesticides seem less likely. In the recent experiment, Pettis and colleagues irradiated some hard-hit hives and reintroduced new bee colonies. More bees thrived in the irradiated hives than in the non-irradiated ones, pointing toward some kind of disease or parasite that was killed by radiation.
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Then, scientists finished mapping the honeybee genome and found that the insect did not have the normal complement of genes that take poisons out of their systems or many immune-disease-fighting genes. A fruitfly or a mosquito has twice the number of genes to fight toxins, University of Illinois entomologist May Berenbaum.
What the genome mapping revealed was “that honeybees may be peculiarly vulnerable to disease and toxins,” Berenbaum said.
University of Montana bee expert Jerry Bromenshenk has surveyed more than 500 beekeepers and found that 38 percent of them had losses of 75 percent or more. A few weeks back, Bromenshenk was visiting California beekeepers and saw a hive that was thriving. Two days later, it had completely collapsed.
