Honeybees responsible for decreasing population of bumblebees: study

There are several species that are staring at the risk of extinction. One such species is that of bumblebees that are on the verge of extinction because of diseases spread by domestic honeybees, reports a recent study.

"Several of the viruses associated with bumblebees' trouble are moving from managed bees in apiaries to nearby populations of wild bumblebees and we show this spillover is likely occurring through flowers that both kinds of bees share," said Samantha Alger, a scientist who led the new research published in the journal of PLOS ONE.

"Many wild pollinators are in trouble and this finding could help us protect bumblebees. This has implications for how we manage domestic bees and where we locate them," she said.

Around the globe, the importance of wild pollinators has been gaining attention as diseases and declines in managed honeybees threaten key crops. Less well understood is that many of the threats to honeybees (Apis mellifera) including land degradation, certain pesticides, and diseases also threaten native bees, such as the rusty-patched bumblebee, recently listed under the Endangered Species Act; it has declined by nearly 90 per cent but was once an excellent pollinator of cranberries, plums, apples, and other agricultural plants.

The research team explored 19 sites across Vermont. They discovered that two well-known RNA viruses found in honeybees - deformed wing virus and black queen cell virus - were higher in bumblebees collected less than 300 meters from commercial beehives.

The scientists also discovered that active infections of the deformed wing virus were higher near these commercial apiaries but no deformed wing virus was found in the bumblebees they collected where foraging honeybees and apiaries were absent.

Most impressive, the team detected viruses on 19 per cent of the flowers they sampled from sites near apiaries. "I thought this was going to be like looking for a needle in a haystack. What are the chances that you're going to pick a flower and find a bee virus on it? Finding this many was surprising," said Alger.

In contrast, the scientists didn't detect any bee viruses on flowers sampled more than one kilometre from commercial beehives.

Alger is deeply concerned about the long-distance transport of large numbers of honeybees for commercial pollination. "Big operators put hives on flatbed trucks and move them to California to pollinate almonds and then onto Texas for another crop," she said.

"This research suggests that we might want to keep apiaries outside of areas where there are vulnerable pollinator species, like the rusty-patched bumblebees, especially because we have so much more to learn about what these viruses are actually doing to bumblebees," Alger said.

Honeybees are an important part of modern agriculture, but "they're non-native. They're livestock animals. A huge misconception in the public is that honeybees serve as the iconic image for pollinator conservation. That's ridiculous. It's like making chickens the iconic image of bird conservation," Alger concluded.