Since twenty years, bees have been suffering a global decline caused by multiple factors. This phenomenon is particularly affecting Europe, North America and Central America. This has resulted in worrying mortality of honeybees (called colony collapse syndrome). This decline is also affecting wild bees. Many research projects, both at the national and European or international level revolve around this phenomenon and its origins.

A worrying trend

Between 2006 and 2007, a loss of 60% of honeybee colonies was observed in the USA, 40 % in Quebec, 25% in Germany and in many other European countries. Wild bees are also under threat. However, since they are mostly solitary, when a wild bee disappears, it is a breeder that is disappearing. This results in a decrease in the number of species of wild bees.

Belgium is no exception to the decline of bees observed around the world. Of the known species, more than half are rare or in very sharp decline. Some have even completely disappeared from the country. The honeybee, Apis mellifera, is also threatened. The excess mortality rate observed in the Belgian apiaries has risen from 17% in 2004 to 28% in 2011.

Reasons for the decline

There are many causes for the phenomenon of decline of the bees. Some of these factors particularly affect honeybees. This is the case of diseases (parasites, viruses, bacteria and fungi), and the loss of immune capacity due to low genetic diversity within the Apis mellifera species. Some beekeeping practices could also contribute to weakening of the honeybees.

Other factors are common to all species of bees. Chemical contamination (through pesticides and biocides) is increasingly challenged by the scientific community as one of the major threats to the bee community. In Europe, some invasive alien species pose a potential threat to bees. Erosion of biodiversity, and thus the decrease in food resources is a key factor in the decline of bees. Other little known factors are under consideration and must be investigated, such as electromagnetic pollution and the effect of the development of genetically modified crops.

Finally, a poorly studied phenomenon is the synergy between these factors, plus the influence of climate change.


Given these findings, several research initiatives have been launched in Belgium, in the European Union and internationally. Their goal is to collect data on the factors involved, to follow the evolution of honey bee colonies and wildlife populations, and to identify measures and actions for prevention and mitigation. One of the actions of Bee Plan 2012-2014, Action 13, plans to focus the federal research programmes around the theme of pollinators.