Preventing the economic sting of `killer' bees
San Francisco — The reputation of the so-called ``killer'' bees, properly known as Africanized bees, apparently is well deserved. But it's the economic sting of the bee that troubles California officials. State and federal agriculture officials -- setting out honey-water bait, checking under the eaves of houses, and looking in chimneys, pipes, and hollow trees -- are searching a 400-square-mile area for four swarms of the insect presumed to be the offspring of a single colony of the bees. The abandoned hive of that colony, believed to have arrived here aboard oil-field equipment from South America, was found last week in an oil field in Lost Hills, Calif.
The intensity of the search isn't because of physical dangers the bees pose to man -- though the danger can be serious on occasion if the easily-excited bees are provoked. The problem is the potential agricultural losses if the bees were able to overtake their gentler, more productive pollinating cousin, the European-variety honey bee.
Whole crops depend on bees for pollination -- almonds, watermelon, peaches, alfalfa, and zucchini, for example. The Africanized bee crossbreeds with the European honey bee, and the resulting offspring inherit the aggressive behavior. Their restless and erratic activity makes them prone to swarming (when a queen bee takes flight and the colony follows). A swarm is usually for reproductive purposes, but Africanized bees swarm and move away if agitated, making them unreliable pollinaters, says Marshall Lev in, director of the Carl Hayden Bee Laboratory in Tucson, Ariz.
Scientists had expected the migratory insect, derived from the African bee, to arrive in the United States in 1990. It was introduced in the Western Hemisphere in the 1950s, when 26 colonies of the bees were accidentally released during a genetic research program in Brazil. The bees have multiplied, overtaking local bee populations and hopscotching north and south at a rate of 100 to 200 miles a year.
Federal and state agriculture officials, anticipating the bees' arrival, have conducted studies of the migratory insects for more than five years. One scientific advisory panel of apian experts, set up last year, hadn't even met for the first time before its members were convened in Lost Hills Tuesday to pool information and field questions for state officials.
``They are not roaming streets looking for men, women, and children,'' says Robert Dowell, an economic entomologist with the California Department of Food and Agriculture. ``These honey bees are no worse than any other honey bee [when it comes to a single sting on a human being]. . . . The difference is there are larger numbers of them, and they will follow you a quarter- to a half-mile rather than just 20 or 30 yards [like the European bees] when their nest is disturbed,'' he says. The bees reportedly attacked and killed a fox, whose hole they took over in Lost Hills.
But, Dr. Dowell explains, the real problem is the agricultural losses that could occur if these insects establish themselves here. ``If we have a 10 percent loss of pollination effectiveness, or a 1.1 billion pound loss in produce, that means crops worth $190 million to $380 million that will be nonexistent. That's the problem we face.''
Farmers must rent two or three hives per acre for effective pollination. The rental rate this season for almond pollination is $22 to $28 per hive for the whole season.
Dr. Levin explains how costs to farmers, and ultimately to shoppers, could rise if Africanized bees establish themselves here. It is known that pollination occurs most efficiently if hives are placed in or alongside the crops. But Africanized bees can't tolerate the human activity if the hive is placed so close to the field -- slight disturbances will make them swarm and relocate. These colonies must be isolated -- and many more hives are needed to ensure that enough bees find their ways to the field fo r pollination. A doubling of hives would mean a doubling of costs -- on a 100-acre farm, pollination costs could increase from $2,800 to $5,600, Levin explains.
So far in Lost Hills, authorities have tested 9,000 commercial and wild hives. Commercial beekeepers and hobbyists are not being allowed to bring bees in or out of the 400-square-mile area. The strategy, based on the presumption that the four swarms have not left the area, has been simply to try to locate the Africanized bees and destroy them.
Although the area of the search may be expanded, however, the search techniques are so thorough ``that if we don't find them, we'll be confident they didn't make it,'' Dowell says.
One-third of all these swarms typically won't survive in nature, he says. It would take more than one hive and its descendants to solidly establish this species here.
While eradication may be possible, scientific study is largely focused on how to live with the Africanized bee when it does arrive here en masse in the future, Levin says. He explains that through interbreeding, the bee that arrives here in 1990 may be significantly genetically different -- and even less aggressive -- than the breed that left Brazil in 1957.