Parasitic mites appear to be the cause of the deformed wing virus spreading throughout bee colonies, according to new research from the University of Sheffield.
The virus is thought to be one of many factors contributing to the collapse of honey bee populations worldwide. It’s probable that the virus has contributed to the deaths of millions of honey bee colonies worldwide. The monetary value of honey bees to US agriculture is estimated to be about $15-20 billion annually.
The research was conducted in Hawaii and showed how the Varroa mite caused deformed wing virus (DWV) to increase its frequency among honey bee colonies from 10 per cent to 100 per cent.
The changes were in unison with a million-fold increase in the number of virus particles infecting each honey bee, and a great reduction in viral strain diversity, leading to a single virulent strain of DWV.
Dr Stephen Martin, of the University of Sheffield’s Department of Animal and Plant Sciences, said: “Just 2,000 mites can cause a colony containing 30,000 bees to die. The mite is the biggest problem worldwide for bee keepers; it’s responsible for millions of colonies being killed.”
“Understanding the changing viral landscape that honey bees and other pollinators face will help beekeepers and conservationists worldwide protect these important insects. We have discovered what happens at the start of an infection. The goal is to understand how the infection comes about so that we can control it.”
“Deformed Wing Virus is naturally transmitted in bees through feeding or sex but the mites change the disease so it becomes more deadly, shortening the bees’ lives.”
As the mites and the new virulent strain of DWV spread through the Hawaiian Islands, the honey bee colonies there will come to resemble the colonies in the rest of the work, where the mite and virus are already well established.
“This ability of a mite to permanently alter the honey bee viral landscape may by a key factor in the recent colony collapse disorder (CCD) and over-wintering colony losses (OCL) as the virulent pathogen strain remains even after the mites are removed.”