An EU-wide study of honeybee colony losses has revealed that bees in Northern Europe – including the UK – have been hardest hit by collapses.

image expired

The study was conducted across 17 of the 28 member states. In what the European Commission has called the bloc's most comprehensive look into bee deaths, EU researchers assessed the health of bee colonies in autumn 2012 and then again in Spring and Summer 2013 to estimate the mortality rates of the colonies. They also recorded information on farming practices and any incidences of major bee parasites and disease.

Only honeybees living in managed colonies were assessed as part of the work, though there are also widespread concerns for the health of wild bees; a quarter of Europe's 68 bumblebee species are thought to be at risk of extinction. Although notes were made on farming practices, only disease and parasite incidence was studied as part of the research, not pesticide impact.

The EU is currently facing legal challenges from manufacturers of several pesticides – amongst them three neonicotinoids – which have been made subject to tight restrictions in light of evidence that their use may be harming pollinating insects, including bees. The Commission had requested that the impacts of pesticide use be included in the Epilobee study, but member state governments blocked the request. This oversight was criticised by scientists when the Commission made its bee study public on Monday.    

The Epilobee researchers studied almost 32,000 colonies in all. The results of their analysis show a distinct north-south pattern of bee mortality across Europe. Overall, winter colony mortality rates ranged from 3.5 percent to 33.6 percent in the states studied.

Northern states worst affected

In southern states, including, Greece, Hungary, Italy, Lithuania, Slovakia and Spain over-winter colony losses were below 10 percent. In Germany, France, Latvia Poland and Portugal mortality rates were noticeably higher, ranging between 10 and 15 percent. More alarming still, in more northerly countries, including Belgium, Denmark, Estonia, Finland, Sweden and the United Kingdom, these were above 20 percent.

Over-winter mortality rates in the UK were amongst the highest recorded as part of the study, coming second only to Belgium, with 28.8 percent of colonies affected.

During the beekeeping season, colony die-offs were rarer, affecting between 0.3 percent and 13.6 percent of colonies. In-season mortality rates did not share the same pattern as winter die-offs; France had the highest rate of loss, though losses in Belgium and the UK remained high (at 8.9 and 9.7 percent respectively to two countries suffered the second and third highest in-season losses).

Rates of disease did not correlate with higher colony mortality in the observations. Prevalence of most major diseases was found to be low, though varroa mites were found in every state. The researchers said that, in all, the Epilobee monitoring project had proven itself to be a useful surveillance tool.

Commission spokespeople have since declared that the research showed colony deaths were lower than feared across the bloc. Bee losses in the EU were lower than in the United States, though the decline of insect pollinators across the Northern hemisphere remains perplexing, and could potentially impact on food production.

However, though the new study will provide useful information for policy makers, and give researchers a clearer picture of trends around the EU, it does not fully indicate how different factors, including habitat loss, climate change, disease and exposure to potentially harmful chemicals, are impacting on bees.

Nevertheless, the project is ongoing, and more information has been collected over the past autumn and winter.