Bees and keepers tackle mite-y problem.

If you find you've been paying a high price for honey lately, you can blame it in part on the varroa mite. It's the most destructive of the two kinds of mites that have infested and devastated honeybees across North America (SN: 6/29/96, p. 406). Like a tick ingesting human blood, the varroa mite feeds off the bee's bloodlike hemolymph. Ferried back to the hive, the mite seeks out a honeycomb cell and feeds on the eggs and pupae there.

"It's a serious problem," says Thomas E. Rinderer of the U.S. Department of Agriculture honeybee lab in Baton Rouge, La. "The solution is a ways off."

At a conference on honeybees last month in Memphis, researchers discussed what that solution might be. Several biological strategies are in the works, such as developing bees that groom to rid each other of the mites or infesting hives with a benign strain of varroa mites that could pre-empt the more virulent pests. Honeybees from the Primorsky region in eastern Russia seem to have a genetic resistance to varroa mites and, pending USDA approval, are to be imported this summer for quarantine, study, and possible use by U.S. beekeepers. Such methods could eliminate or minimize the use of chemical controls, to which varroa mites are already showing resistance.

Another biological strategy involves selectively breeding for "hygienic" honeybees. Bees with this naturally occurring behavioral trait cue into the presence of varroa mites in cells and evict them. Entomologist Marla Spivak of the University of Minnesota in St. Paul reported at the meeting and in the December 1996 Apidologie that in 2 out of 3 years her hygienic honeybees removed most of the infested pupae in test colonies. In three out of four commercial apiaries, the hygienic bees had fewer mites than nonhygienic bees did.

Rinderer says it will probably take several strategies in concert to vanquish the mite. Honeybees may eventually develop their own natural resistance, he adds.