Almost a fifth of bee colonies in Switzerland failed to survive the winter. Losses have been greater than in previous years. +Get the most important news from Switzerland in your inbox The Lake Geneva region has been hardest hit, Apisuisse reported on Wednesday. According to the traditional winter mortality survey, 18.9% of colonies did not make it through the cold season, a proportion up 4% on the previous year. + Read about Switzerland's 'battle of the bees' Bee colony mortality was highest in the Lake Geneva region, at 28.9%. The canton of Zurich (23.3%) and Ticino (22.5%) were also above the national average. Central Switzerland has the lowest mortality rate, at 15.8%. 'Cement' honey Winter mortality in bee colonies is a complex phenomenon. For around two decades, losses have fluctuated at a high level, with no clear trend, according to Apisuisse. This winter, forest honey has attracted particular attention. Colonies that spent the winter on forest honey recorded significantly ...