Parasitic mite spreads lethal virus to honeybees
June 27, 2014
From: Planet Earth Online
A parasitic mite has helped spread a particularly nasty strain of a virus to countless honeybees, helping to wipe out hundreds of colonies, according to the latest study.
A UK team of researchers found that when the Varroa mite gets into hives, it massively amplifies a disease-causing strain of deformed wing virus (DWV), rendering bees unable to forage properly and leading to high colony losses.
The findings explain why the bloodsucking parasite, which has long been considered one of the biggest threats facing honeybees, is such bad news for bees and beekeepers.
‘We find deformed wing virus in almost all colonies – it’s one of the most common viruses that affects honeybees,’ says Professor David Evans of the University of Warwick, who led the study.
‘But we only find high levels of this virulent strain of the virus when the Varroa mite has fed on the developing bee. In this case it accounts for more than 99.9% of the DWV present.’
DWV is common in UK honeybees. Lots of different strains of the virus exist, but only at low levels which means it’s usually harmless. Mites feed on young, healthy developing bees’ blood, taking in this mixture of virus strains. When they move to another developing bee they inject the mixture and the virulent strain of DWV out-competes all of the others and replicates to very high levels.
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