A Swedish Beekeeper Association poll found that 23 percent of nearly 2,000 beekepers' bee colonies died this past winter, a two-fold increase from the previous year.
"Of course it's not good if you lose so many bees, it's a major financial hit for the beekeepers," says Preben Kristiansen, a bee health consultant.
One bee colony can produce anywhere from 20 to 100 kilos of honey, so "we can be talking about thousands of kronor in losses per colony," Kristiansen says.
He says bee experts do not know why so many bees have died. But one theory is that a cold and rainy August may have weakened these so-called winter bees.
The Swedish Beekeeper Association plans to analyze the poll further to determine why there are variations depending on where in the country the bees were farmed.
And it warns that continued problems may lead to honey shortages.