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Entomologist Elliud Muli, a beekeeping expert at the International Center for Insect Physiology and Ecology (ICIPE), teamed up with researchers at Penn State University to survey beehives in all of Kenya’s major ecosystems: savanna, mountains, tropical coast, and desert. They measured the sizes of hives and the numbers of bees and tested them for parasites and pesticide contaminants.

In a paper published today in the online journal
PLOS ONE, the researchers report that honeybees in Kenya are infested with the same nasty pests and diseases that wipe out hives elsewhere-but what’s surprising is that they don’t succumb. Hives remain healthy even where a combination of pathogens are present.

“That resilience-I was amazed by the lack of manifestation of ill health in the bees,” says Muli.

Vanishing Bees in the West

In hives afflicted with colony collapse disorder (CCD), the name given to a mysterious condition that began killing U.S. honeybees in 2006, adult bees simply vanished from hives, leaving the queen behind. According to a report issued last year by the U.S. Department of Agriculture, since that time U.S. commercial beekeepers have lost some ten million hives and $2 billion.

Though some of that is due to normal wintertime attrition, the report said, CCD is thought to have at least doubled normal losses and in some cases wiped out more than 90 percent of hives. It was a particularly major threat to crops pollinated by bees trucked in by commercial keepers-especially almonds in California, which require the services of 60 percent of all hives in the U.S.

CCD had no smoking gun; scientists finally determined that no one pathogen or chemical or environmental problem was to blame. Instead, it was an onslaught of many factors, all of which continue to weaken and wipe out hives nearly a decade later.
Varroa mites plague colonies throughout the Western world, and since invading the U.S. in 1987 have “caused hives to crash all over the place,” says Penn State’s Christina Grozinger, a coauthor of the Kenya study. The gut parasite
Nosema is another menace. Beekeepers keep up a constant chemical battle to fight off these two killers but often lose. (See “The Plight of the Honeybee.”)

Though many pesticides are deemed safe for use, components in them weaken bees’ resilience, as do other chemicals applied to the crops they pollinate. Poor nutrition from a monoculture diet and the stress of being carted from state to state are factors. There are also viruses that join forces with parasites to knock the insects out. “It’s now well accepted that our honeybees are dying because of the synergistic effects of multiple stressors on their immune systems,” Grozinger says. “We have worn them down bit by bit until they can’t take any more.”