[T]here has been no shortage of media coverage in the past few years about the host of problems facing honey bees, from varroa mites to climate change. And, more recently, increasing attention has also been paid to the plight of wild pollinators — including bumble bees.
A new study from a team of UVM and University of Florida researchers suggests that viruses plaguing honey bees could be “spilling over” to wild bumble bees — highlighting the need for proper management of commercial bees.
They found that two RNA viruses — deformed wing virus and black queen cell virus — were more common in bumble bees caught near beehives, according to a study published last week in PLOS ONE (a peer-reviewed journal from the Public Library of Science).
Previous research has shown that viruses spread between different kinds of honey bees —- and between commercial bumble bees and wild bumble bees, said Samantha Alger, a research affiliate with UVM and co-author of the study.
“The link hadn’t been made for pathogens spilling over from honey bees to bumble bees,” she said. “Our study tested and found that it looks like … spillover is occurring from honey bees to wild bumble bees — and it’s likely occurring through flowers.”
Bumble bees are one group of native Vermont bees. In contrast, while honey bees can be found in Vermont in both managed beehives — called apiaries — and in the wild, they were originally brought to the U.S. in the 1600s by European settlers.
The team of UVM researchers collected flowers, honey bees, and bumble bees around Vermont, sampling from seven sites by apiaries and 12 sites with no apiaries within a kilometer.
Alger said one of the most surprising findings was that they were able to find bee viruses on flowers — and only on flowers near apiaries.
“We thought it was totally going to be like looking for a needle in a haystack, like what’s the likelihood of finding a bee virus on a flower in a field,” she said. “And when we got around to testing them, we were like, oh my god, it’s way higher prevalence than we thought, and only flowers that we collected from sites where there was a honey bee apiary present had viruses on them.”
Alger said little is known about how the RNA viruses — once thought to only be found in European honey bees — impact wild bumble bees as it is “difficult to find sick bees.” Research is needed in a laboratory setting on how RNA viruses impact bumble bees, she said.
Almost half of Vermont’s bumble bees are extinct or in serious decline, according to a study that came out this winter from UVM’s Gund Institute and the Vermont Center for Ecostudies.
The new study did not show that viruses from honey bees were causing the decline in wild bees, Alger said. Leif Richardson, an ecologist at UVM’s Gund Institute, said in an interview last year that climate change, habitat loss, pesticide use, and parasites and pathogens were all likely contributing factors.
As a beekeeper, Alger stressed that the researchers were not seeking to “villainize” beekeepers, but rather hope the research would point to the need for more educational resources for beekeepers.
“The take home message for beekeepers is to treat their (varroa) mites properly,” she said.
Varroa mites feed on bee larvae, transmitting bee diseases in the process.
“Varroa is still the No. 1 enemy, in my humble opinion, and it has resisted the industry’s several attempts to neutralize it,” said Bill Mares, longtime beekeeper and advisory board member of the Vermont Beekeepers’ Association. He added that climate change, pesticides and “loss of forage” are also impacting honey bees.
“I had a terrible year (last year), it’s the worst year I had in 25-30 years and I thought I was doing most things right,” he said.
Both Alger and Mares said the state needs a strengthened apiary inspection program, which Mares said would serve as a “police power” to deter beekeepers who were not properly managing their bees.
This year lawmakers passed a law, Act 35, last session that the Vermont Beekeepers’ Association and pollinator activists had been lobbying for. The bill restricts use of neonicotinoid pesticides so that only certified applicators can buy and use that class of pesticides as of July 1.
The law creates a new “pollinator specialist” position at the Agency of Agriculture, Food and Markets and strengthens regulations around importing bees.
The law also requires the Agency of Agriculture to partner with the VBA to set-up a voluntary beekeeper education program.
Cary Giguere, director of public health and agricultural resource management for the agency, said H.205 enables a tripling of state apiary inspection efforts by adding an additional full-time position. He said the agency is starting to hire this summer for that position and for a pesticide enforcement position to roll out the new neonicotinoid restrictions.
He added that the bill will allow also allow the agency to regulate other bee pests and diseases, like varroa mite, in the way it currently does for American foulbrood.
Giguere credited Rep. Chip Troiano, D-Stannard, for sponsoring a “very progressive pollinator health” bill.
“There’s no other bill like it in the country,” he said.
Ed. Note — Bill Mares is on the board of the Vermont Journalism Trust, doing business as VTDigger.