Bee Ⓒ Gilles San Martin

Swiss research for sick bees

The sharp decline in bee colonies all over the world since 2000 has not overlooked Switzerland. A national research centre is working together with beekeepers to find out what is causing this phenomenon and what can be done about it.

Switzerland’s image as a land flowing with milk and honey is both figuratively and literally correct, particularly the amount of honey produced by one of the world’s highest bee population densities. But the honeybees don't just make honey. Together with their wild species, they are responsible for 80% of plant pollination – a key role in the production of food. But since 2000, Switzerland and the rest of the world have seen a dramatic fall in bee colonies that is particularly unusual.

On the outskirts of Bern in Liebefeld, researchers at the Agroscope Swiss Bee Research Centre are trying to uncover the causes of this calamity that is threatening the balance of nature and, together with beekeepers, are looking for ways to respond.

Beehives belonging to the Swiss Bee Research Centre Ⓒ Agroscope

The centre was founded in 1907 and was the only institution in Switzerland solely dedicated to bee research for a long time. Since 2013, it has been sharing the field with the Bee Health Service (training, knowledge transfer) and Institute of Bee Health at the University of Bern (basic research). In addition, the centre launched the Coloss (‘colony losses’) network which brings together more than 800 researchers from 92 countries.

Deadly parasite

“The bees’ enemy number one is the Varroa mite,” explains Jean-Daniel Charrière, a researcher at Liebefeld. This crab-like mite originating in Asia arrived in Europe more than thirty years ago after having come into contact with the European honeybee. It reproduces inside the bees’ brood cells until the adult bee emerges from the cell. In contrast to its Asian cousin, the European honeybee has no line of defence against the parasite, which also carries viruses. “If no action is taken, more than 95% of the colonies will be destroyed,” says Charrière.

Beekeepers first began using chemical products to fight Varroa mites, but this creates resistance issues and the substances were also found in the beeswax and honey. Researchers at the centre quickly saw this impasse and turned to alternative methods such as using formic and oxalic acid. And it works. “Using organic substances helps keep the mites under control,” asserts Charrière. “But you need nimble fingers and commitment.” According to Charrière, beekeepers in Switzerland have followed suit – and more than three-quarters are using such methods today.

The Varroa mite
The Varroa mite, enemy number one for honeybees Ⓒ Gilles San Martin

A lack of explanation

Even if winter colony losses in Switzerland have been limited in certain years, records show that losses of around 20% on average during the critical winter months are becoming more and more common. That’s twice as much. Varroa mites alone are not responsible. “We don't understand the phenomenon completely,” admits Charrière. “A lot of theories have been put forward, like electromagnetic waves for example, but I don't believe in that very much.” And pesticides? Since 2013, the use of three types of insecticides on corn and rapeseed crops in Switzerland has been discontinued. “That’s a good thing,” says Charrière. But he still hasn't noticed any real impact on the health of the local bee population for the moment.

The Federal Council also provides direct payments for farmers to plant strips of flowers along their crops to promote pollination and has created provisions to reduce pesticide-related risks. These measures are intended to better protect bee colonies that are located close to crops and were introduced under the national action plan for bee health adopted in 2014. Both the honeybee and wild bee species are being targeted under these efforts because if the media only focuses on the plight of honeybees, their survival may be guaranteed – but not that of other non-domesticated species.

Strips of flowers
Switzerland encourages farmers to plan strips of flowers along their crops to promote pollination Ⓒ Matthias Tschumi/Agroscope

The end of romanticism

“There are many factors involved in the bees dying,” notes Gérald Buchwalder, a beekeeper from the Jura who has carried out tests together with the Bee Research Centre. He owns around 12 beehives in the Delémont valley and looks after the 30 colonies belonging to the Jura Region Rural Foundation where he heads the beekeeping project. The foundation keeps detailed statistics on beekeeping in the region. “For example, we’ve noticed that the colonies at a higher altitude have more resistance than those in the lowlands,” says Buchwalder. “It should be possible to analyse this further to find out why.” The statistics also show that beekeepers with less than ten hives suffer greater losses.

In this uncertain climate, the methods beekeepers use to manage their hives is more important than ever. “First, make sure you follow the advice of the Bee Health Service and the Bee Research Centre,” states Buchwalder. This isn't just in your own interests. Bees fly. So if you neglect your colony, you run the risk of contaminating others nearby... “When I started 30 years ago, I used to visit my hives from time and time and everything was fine,” reminisces Jean-Daniel Charrière from the research centre. “But those days are over. Now, you really have to keep a close eye on your colonies.”

One of the Bee Research Centre buildings in Liebefeld
One of the Bee Research Centre buildings in Liebefeld Ⓒ Agroscope