Mystery illness devastates honeybee colonies

From New Scientist:

• 12:31 14 February 2007
• NewScientist.com news service
• Roxanne Khamsi

A mysterious illness is devastating honeybee populations across the US from California to Florida, claiming up to 80% of colonies in some areas. The losses of honeybees could disrupt the pollination of food crops, researchers warn.

Beekeepers are finding once-healthy colonies abandoned just a few days later, says Jerry Bromenshank, at the University of Montana at Missoula and Bee Alert Technology, a company monitoring the problem: “In most cases the only one left is the queen, along with a few young bees.”

The absence of dead bees makes it difficult to know what ails them and where they have gone. Furthermore, experts cannot track the spread of the mysterious illness. “The problem is that it strikes out of the blue,” says Bromenshank.

At a loss for an explanation, researchers have referred to the honeybee decline as “colony collapse disorder”. Reports of the problem have intensified in recent weeks and spanned 22 states, but some beekeepers say that they began seeing their colonies decline almost two years ago.

Almonds and apples

Researchers say colony collapse disorder might be a re-emergence of a similarly mysterious illness that struck US honeybees in the 1960s. Experts never pinpointed the cause behind that previous bee crisis, according to Bromenshank. He notes that in light of this some people have jokingly termed the problem the “disappearing-disappearing illness”.

But beekeepers and farmers see no humour in the potential economic costs of drastic honeybee decline. Almond crops are immediately vulnerable because they rely on honeybee pollination at this time of year. And the insect decline could potentially affect other crops later in the year, such as apples and blueberries.

Bromenshank speculates that dry conditions in the autumn reduced the natural food supply of the honeybees, making them more vulnerable to some sort of virus – such as deformed wing virus – or fungal infection. He notes that the abandoned colonies are not repopulated by other honeybees or insects for at least a few weeks. This, he says, is consistent with the presence of toxic fungal residues from the dying bees that repel other insects from re-inhabiting the colony.

Other scientists have tentatively blamed the problem on pesticides or chemicals specifically designed to control mites in bee colonies.

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This seems related to colony collapse disorder, which has struck before.