Over the last four years, millions of the West's workers have vanished. No, they're not immigrants deported back to Mexico. Rather, they're honeybees, and no one's sure where they've gone. Scientists have been baffled by the large-scale disappearances, but now there's finally some good news: Recent research has identified at least three of the major contributors to what's known as "colony collapse disorder."
Honeybees pollinate nearly one-third of the food we eat, from almonds to avocados, cherries to celery, and their work adds about $15 billion to the annual value of U.S. agriculture, according to a congressional study. But in Western states from California to Montana, thousands of hives have gone quiet. They contain larvae and honey but very few adult bees, and that decline bodes ill for our food supply. In China, hive collapse has forced some farmers to start pollinating fruit trees -- by hand -- with brushes.
So far, there are still enough honeybees to go around, at least on a small scale. The gnarled apple tree in my backyard, for instance, is loaded with ripening fruit, thanks to the honeybees who visited it earlier this spring. But it's a different story for commercial growers with hundreds of acres of monoculture crops. Other pollinators, like native bees and wasps, can't meet the demands of servicing, say, 500 acres of almonds in bloom. So almond ranchers rent honeybees from nomadic beekeepers who haul hundreds of hives from farm to farm, all the way from North Dakota to California, then back again. With the scarcity of healthy bees, the cost of renting a single hive for a few weeks is now as much as $200, up from just $40 a few years ago.
Scientists have had lots of clues to follow in this mystery. They've considered parasitic mites, viruses, malnutrition, pesticides, genetically modified crops, even cell phones. But even before colony collapse disorder, domestic bees, brought to this country from Europe, weren't faring so well. Their habit of crowding into hives allows illnesses and parasites to spread easily. Modern agriculture has also been hard on those traveling hives, which account for more than half of the country's honeybees. When crops aren't in bloom, itinerant beekeepers feed their bees high-fructose corn syrup. Life on the road and a junk-food diet stresses the bees, and makes them more susceptible to infections of all sorts.
Now, researchers are finally homing in on the causes of colony collapse disorder – and there seem to be many. Scientists with the U.S. Department of Agriculture and the University of Illinois just discovered that sick bees have high levels of viral infections, carried by mites, that attack protein-producing ribosomes essential for good health. At Washington State University, researchers recently identified two other factors. One is a pathogen called Nosema ceranae, a microbe that impairs the bees' ability to process their food and makes them more susceptible to other diseases. Scientists in Spain also connected the microbe with colony collapse this spring, finding that antibiotic treatment restored infected colonies to health.
Another factor the Washington scientists noted is that U.S. beekeepers use the same honeycombs for many years, allowing toxic levels of pesticide residue to build up. Traces of more than 70 different pesticides have been detected in honeycomb wax. Mark Pitcher, the president of Babe's Honey in British Columbia, told the Victoria News that the connection to the bees' disappearance seemed obvious: "Would you allow your youth to be raised in a totally ridiculous slum environment? No. So why did we, as beekeepers, become slum landlords?"
Some beekeepers are now sand-blasting their hive boxes, getting rid of the old honeycomb wax and repainting with nontoxic paint. Others are letting their honeybees forage only in areas where pesticides and herbicides aren't used. In the meantime, native bees may help pick up the pollination slack: Species such as bumblebees, alfalfa leaf-cutting bees and blue orchard bees pollinate certain crops even more effectively than the exotic honeybee. The wild bees need other plants to forage on when crops aren't in bloom, though, and habitat loss has cut into their populations. To help restore native bee habitat, The Xerces Society just got a $500,000 federal grant for work in California and Oregon.
By cleaning up our act, perhaps we can turn the corner on the bee crisis. The solutions seem common-sense. If we stop drenching the plants that bees visit with toxic chemicals, clean up their hives and quit trucking them thousands of miles, and if we give our native bees more forage in the field, maybe we can avoid a grim future in which we, like those Chinese farmers, must tickle each apple blossom with a brush to make it bear fruit.
Jodi Peterson is a contributor to Writers on the Range, a service of High Country News (hcn.org). She is the magazine's associate editor in Paonia, Colorado.