Harvest threat: so few bees, so many crops
When was the last time you saw a honeybee on a flower? If the answer is "not recently," it wouldn't be surprising.
It's not easy being a bee in America. In the 1980s, wild bees in the United States were devastated by an invading parasite, the varroa, or "vampire mite." Since then, the situation has gotten even worse.
The bee population has been steadily dropping, mainly because of varroa but also because of pesticides and predator birds.
Now, as pollinating season hits full swing in the United States, farmers of the 90 or so crops that depend on bees for pollination are feeling the tightest pinch ever.
"For the first time in our history [pollination] is a limiting factor in crop production," says Keith Delaplane, professor of entomology at the University of Georgia's College of Agricultural and Environmental Sciences. "For a long time ... it was one of those things that just took care of self."
With virtually no wild honeybees left, US farmers rely on commercial bee colonies. But this year only about 2.6 million colonies remain to pollinate the millions of acres of melons, cucumbers, almonds, apples, avocados, and kiwi, to name some of the crops that depend on honeybees. That slender bee army - down from 3.2 million colonies in 1990 - is all that stands between Americans and a vastly more boring diet.
Scientists and beekeepers are feeling the pressure. Hope for crop pollination this year rests temporarily on new chemicals to kill the bee parasites, but the mites have been developing resistance to them. So researchers are exploring long-term solutions such as genetically altered bees that can resist mites or bees that are imported from eastern Russia and have adapted to the varroa mite.
Some bee experts worry that regional shortfalls in bee availability are only going to get worse before they improve.
"We're very concerned about the declining effectiveness of the chemicals," says Troy Fore, executive director of the American Bee Keeping Federation in Jessup, Ga. He says there's a threat the mites could wipe out more commercial bee colonies in coming years if new solutions are not found soon.
Perhaps the most extreme example is California's big almond crop (1 billion pounds annually) that requires pollination every February. This year, there were barely enough bees to pollinate the state's 520,000 acres of almonds, says Joe Traynor, a pollination broker in Bakersfield, Calif., who matches farmers with beekeepers.
With two bee colonies needed per acre, more than 1 million hives are required. California has about 500,000 hives and about another 500,000 were trucked in. Some farmers who wanted two hives made do with a hive and a half.
"There's clearly a shortage of bees for almonds," Mr. Traynor says. "That's where your crunch is."
The bee pinch, he says, is not nearly as tight for most other bee-pollinated crops such as apples, cantaloupes, or cucumbers because there are fewer total acres and commercial beekeepers can keep up with demand.
Honeybees are not native to the US. A British subspecies arrived with colonists in 1680 and spread rapidly nationwide. In 1984, though, beekeepers discovered that a new parasite, the trachea mite, was devastating wild and commercial colonies.
Already, the impact of the mites over the past 15 years has been huge. In Florida, for example, the number of commercial bee colonies has fallen from about 360,000 around 1990 to just 220,000 today, according to Laurence Cutts, Florida's recently retired top bee inspector.
"There's a lot of concern out there, because the surviving beekeepers know that if we don't find some way to control varroa they're going to lose their business," says Frank Eischen, a research entomologist for the US Department of Agriculture who is working on a new generation of chemical pesticides to kill bee mites. "I have great hope we will get through this gap."
But Dr. Eischen calls any chemical treatment a "Band-Aid" approach that won't last. Instead, he says the best hope for US bees is for a genetic solution - an internal modification of the bees that makes them immune or resistant to varroa and other mites. He says several techniques are being explored.
Thomas Linderer, a research geneticist at the USDA's Honeybee Breeding, Genetics & Physiology Laboratory in Baton Rouge, La., thinks Russian honeybees may be the solution.
The bees come from the Vladivostok region of eastern Russia, where they've had 150 years to adapt to the varroa mite and develop a resistance to them.
Charles Harper, a commercial beekeeper from Lafayette, La., is cautiously optimistic about the Russian bees.
About 90 percent of his Russian colonies have survived the past three winters with little need for antimite chemicals. He even dares to hope the new strain may repopulate the US with wild colonies - as the earlier European bees once did.
"I saw a wild colony just the other day in a tree - bees were going in and out, and they had been doing that for three years," he says. "Chances are those bees were Russians. That gives me hope."