The number of honey bee colonies fell by nearly 12% last winter, an international study involving the University of Strathclyde indicates.
Beekeepers in 29 countries reported that, out of nearly 400,000 colonies they managed, 11.9% had failed to survive the winter.
Cases of colonies perishing after problems occurred with their queen were higher than expected.
The UK and Spain were worst affected, compared with the previous year, when other areas of Europe were hardest hit.
The preliminary findings were made through a study by honey bee research association COLOSS, based in the Institute of Bee Health at the University of Bern.
Dr Alison Gray, of Strathclyde's Department of Mathematics & Statistics, a partner in the study, said: "These loss rates vary considerably between countries. In this year's survey the highest losses were found in Ireland and Northern Ireland, followed by Wales and Spain.