Researchers at the University of Sydney have found that the relationship between the tissue-sucking Varroa mite and virulence of a virus of honey bees, has most likely been misunderstood.
The study challenges the long-held belief that the parasitic Varroa mite -- a mite that sucks the tissue of honey bees -- transmits the Deformed Wing Virus of honeybees and in doing so changes the virus to make it more virulent and deadly.
Australia is the only country in the world to remain free of the Varroa mite. This makes Australian honey and wax valuable because it is free of chemical residues used to eliminate the parasite.
"Australia is the last country on the planet to produce completely pure honey," says Professor Madeleine Beekman from the School of Life and Environmental Sciences at the University of Sydney. "But the mite is highly likely to arrive in Australia on shipping containers so we need to understand how the mite and the virus interact."
Professor Beekman and her team in the Behaviour and Genetics of Social Insects Lab injected honey bee pupae with high levels of Deformed Wing Virus which is carried by the mite to test if the virus was highly virulent due to changes in the transmission route that occurred via the Varroa mite.
The team found the transmission route used by the Varroa mite selects against viruses that are much more virulent than the Deformed Wing Virus, such as Sacbrood virus and Black queen cell virus. These viruses normally suppress Deformed Wing Virus. The elimination of Sacbrood and Black Queencell virus leaves just Deformed Wing Virus, which does not kill the bees.
"Our work therefore changes our understanding of the effect Varroa has on Deformed Wing Virus and the health of honey bee colonies," Professor Beekman said.
"It means we don't have to be scared of the virus. Instead we need to focus on eliminating the mite and reducing its numbers."
Read more about this study at Science Daily.