Agriculture/Agriculture One in five Swiss bee colonies did not survive the winter
Almost a fifth of bee colonies in Switzerland did not survive last winter. The losses were therefore higher than in previous years.
04.06.2025, 15:10
SDA
This was revealed by a survey conducted by the Apisuisse beekeepers' association and the Agroscope Center for Bee Research, as announced by the beekeepers' association on Wednesday. According to the survey, 18.9 percent of bee colonies died last winter. In the previous year, the figure was four percent lower.
The highest mortality rate of bee colonies was recorded in the Lake Geneva region with almost a third (28.9 percent). The canton of Zurich (23.3 percent) and Ticino (22.5 percent) are also above the national average. Central Switzerland (LU, UR, SZ, OW, NW, ZG) recorded the lowest loss rate at 15.8%.
Cement honey and mites
The winter mortality of bee colonies is a complex phenomenon. According to Apisuisse, losses have been fluctuating at a high level for around two decades, with no clear trend. This winter, the focus was particularly on forest honey. Colonies that overwintered on forest honey had significantly higher loss rates than those with other feed.
One reason for this could be so-called cement honey: Honey with a high proportion of the triple sugar melezitose, which causes the honey to crystallize in the combs.
According to the beekeepers' association, bees need a lot of energy and water to process this cement honey. It is also difficult for the insects to digest.
Inadequate or late treatment against the Varroa mite, a bee parasite, also had a negative effect. Beekeepers also suspect that the spread of the Asian hornet has an influence.
