Bumblebees living in the wild in the United Kingdom are falling victim to diseases that are easily managed in captive populations. This could suggest parasites are transmitted from managed honeybees to wild bumblebees.
Matthias Fürst and Mark Brown from Royal Holloway University of London, who led the research, came to this conclusion. This new finding may shed some light on vanishing bee populations around the world.
"Wild and managed bees are in decline at national and global scales. Given their central role in pollinating wildflowers and crops, it is essential that we understand what lies behind these declines. Our results suggest that emerging diseases, spread from managed bees, may be an important cause of wild bee decline," Fürst said.
Data was collected on a number of disorders, and the team looked at how these diseases may migrate from managed populations of honeybees to wild bumblebees. Fürst and his team found deformed wing virus (DWV) and Nosema ceranae, a fungal parasite, could move between the groups. Lifespans of bees contracting DWV is shortened from around three weeks to two.
To carry out the study, the team exposed bumblebees to both pathogens under laboratory conditions. The insects quickly caught both diseases, proving they are susceptible. Next, they collected honeybees and wild bumblebees from around England. They found both diseases were present in nearly identical percentage among the species for insects from the same area. They were also the same variety of infection, strongly suggesting inter-species transfer.
"One of the novel aspects of our study is that we show that deformed wing virus, which is one of the main causes of honeybee deaths worldwide, is not only broadly present in bumblebees, but is actually replicating inside them. This means that it is acting as a real disease; they are not just carriers," Fürst said.
Parasites have been named as another leading cause of declining bee populations. The team believes these parasites are left behind on flowers and other surfaces by honeybees. Bumblebees come in contact with these organisms, and fall ill.
If bee populations decline too far, plants and flowers that depend on the pollinators to reproduce could begin to die out. This could have a significant impact on human crops. More than 70 percent of all plants eaten by humans are dependent on pollinators, and bees are responsible for 80 percent of the transfer.
Never before has the movement of disease among bee populations been documented in so much detail. Apiologists believe this research may help beekeepers better manage their populations, as well as minimize their effects on wild populations.
The study of the incidence of these diseases among bees was detailed in the journal Nature.
