Man-made pandemic is killing honeybeesAmy Walsh (Author) Published Date : Feb 05, 2016 18:53 IST
The spread of a disease that is decimating global bee populations is manmade, and driven by European honeybee populations, new research has concluded.
A study led by the University of Exeter and UC Berkeley and published in the journal Science found that the European honeybee Apis mellifera is overwhelmingly the source of cases of the Deformed Wing Virus infecting hives worldwide. The finding suggests that the pandemic is manmade rather than naturally occurring, with human trade and transportation of bees for crop pollination driving the spread.
Although separately they are not major threats to bee populations, when the Varroamite carries the disease, the combination is deadly, and has wiped out millions of honeybees over recent decades. Varroa feed on bee larvae while the Deformed Wing Virus kills off bees, a devastating double blow to colonies.
The situation is adding to fears over the future of global bee populations, with major implications for biodiversity, agricultural biosecurity, global economies, and human health. There are ways to control this.
Varroa mites harm honey bees directly and also spread virus diseases that kill colonies. Professor Francis Ratnieks, head of Laboratory of Apiculture and Social Insects, LASI, stated that controlling Varroa was at first simple, as the product Apistan could be used. Apistan contains a synthetic chemical that kills 99% of the Varroa but is not harmful to the bees. However, Varroa have now evolved resistance to the active ingredient.
Lead author Dr Lena Wilfert, of the University of Exeter's Centre for Ecology and Conservation, on the Penryn Campus in Cornwall, said, This demonstrates that the spread of this combination is largely manmade - if the spread was naturally occurring, we would expect to see transmission between countries that are close to each other, but we found that, for example, the New Zealand virus population originated in Europe. This significantly strengthens the theory that human transportation of bees is responsible for the spread of this devastating disease.
Researchers analysed sequence data of Deformed Wing Virus samples across the globe from honeybees and Varroa mites, as well as the occurrence of Varroa. They used the information to reconstruct the spread of Deformed Wing Virus and found that the epidemic largely spread from Europe to North America, Australia and New Zealand.
They found some two-way movement between Europe and Asia, but none between Asia and Australasia, despite their closer proximity. The team also looked at samples from other species suspected of transmitting the disease, including different species of honeybee, mite and bumblebees, but concluded that the European honeybee was the key transmitter.
Professor Roger Butlin, Professor of Evolutionary Biology at the University of Sheffield, said, The study has found that the deformed wing virus is a major threat to honeybee populations across the world and this epidemic has been driven by the trade and movement of honeybee colonies. Senior author Professor Mike Boots of Exeter and UC Berkeley concluded, it is important to mitigate this and future disease problems.
Man-made pandemic is killing honeybees