Bees face extinction threat through disease transfer

Domesticated bees spreading pathogens to wild species including bumblebees

Domesticated honeybees are spreading diseases from their managed hives to bee populations in the wild. The disease transfer is speeding up the decline of essential pollinators such as the bumblebee, according to research from Britain released this afternoon.

There is international trade in honeybees (Apis mellifera) and their hives need constant management to keep diseases under control. Despite this, researchers from the Royal Holloway University of London have shown at least two diseases are actively being spread from domesticated bees to wild species, according to the study published in the journal Nature.

The bumblebee (Bombus) is in global decline, something that threatens the productivity of farming. The growth of fruit, veg and other crops is dependent on having pollinators of all sorts available but bees are particularly important, the authors write. They decided to study whether disease transfer from managed bees might be putting species like the bumblebee under pressure.

They first tested the idea in the lab with infection experiments and then conducted a large-scale field study across Britain and the Isle of Man. They were looking at two common diseases in domesticated bees, deformed wing virus and a fungal disease that affects bees.


They found that both diseases were actively replicating in honeybees and bumblebees. Genetic studies of the virus also showed that bees tested in shared foraging areas had related strains of the virus showing that there was ongoing disease transmission, the author said.

“Our results provide evidence for an emerging pathogen problem in wild pollinators that may be driven by Apis,” the authors write.

Ireland's 101 native bee populations are also under considerable stress, said Dr Una FitzPatrick, an ecologist at the National Biodiversity Data Centre in Waterford. "A third of the Irish bee fauna is threatened with extinction, " she said.

The primary cause for this was the loss of bee habitat due to increased urbanisation and more intensive agricultural practices, Dr FitzPatrick said. “There are just fewer places where a bee can make a home.”

The decline of bees loss will have an impact on us that people don’t consider. “We forget bees provide an essential service. We are totally dependent on them to pollinate our crops,” she said.

The paper’s findings were no surprise, it had been suspected and now there was evidence of disease transfer, she said. “This is yet another stressor that bee populations don’t need.”

Simple changes could make a difference however like letting wildflowers grow in road margins to make them more pollinator friendly. “Just don’t cut the grass verges so often,” she said.

The research article can be read online at:

Dick Ahlstrom

Dick Ahlstrom

Dick Ahlstrom, a contributor to The Irish Times, is the newspaper's former Science Editor.