A study published by the International Bee Research Association, has provided an overview of the problem of bee colony decline at the European level. As the other pollinators such as wild bees and hover flies are also in decline, this could be a potential danger for pollinator services, on which many arable crops depend says a special edition of the Journal of Apicultural Research.
  
The loss of pollinators such as bees, bumble bees and butterflies is one of the four pillars of the EU project "Assessing Large scale environmental Risks for biodiversity with tested Methods" ALARM and was the largest research project of the European Union in the field of biodiversity.

Over 200 scientists from 35 countries and 68 partner organisations (of which seven were companies) worked on this comprehensive research project between 2004 and 2009, coordinated by Dr Josef Settele (right) from the UFZ with six other colleagues. ALARM was not only one of the largest EU research projects but also one of the most productive: The funding of this project resulted in more than 1000 scientific publications until now. But the bee problem remains.

The compilation provides a preliminary overview of the situation in Europe incomplete however, since France, Spain and some Eastern European EU countries are missing from it, with no suitable data.

While in Europe and the USA the number of bee colonies has declined, the number on a worldwide scale is thought to have increased by approximately 45% over the last 50 years according to a 2009 report from the Food and Agricultural Organisation of the United Nations (FAO).
 
But of little use to the agrarian economy in Europe and the USA, for although honey can be imported, this is not the case for pollination services provided by the bees. 

According to the analysis,bee colony number have already been on the decline in Central and Western Europe since 1965. Since 1985 the trend also become apparent in countries such as the Czech Republic, Norway, Slovak Republic and Sweden.

By comparison, in the South of Europe (Greece, Italy and Portugal) number of bee colonies increased between 1965 and 2005. But numbers of beekeepers decreased in all of the countries that investigated.

Scientists assume the cause to be the social and economic changes over recent decades. Rising incomes of the rural population made other sugar-based products affordable, the replacement of jobs by machines in agriculture speeded up rural exodus to urban regions so hobby beekeeping lost its attraction.
"The price of treating bee diseases has increased to the extent that the cost of treatments may equal or exceed the income from a colony for an entire year, making it uneconomic to keep bees on a small scale", explains Dr. Simon Potts (left) of the University of Reading, England. "Moreover, the effort for treating disease, in particular Varroa destructor, has probably also reduced the attractiveness of beekeeping as a hobby."  

The mystery of bee losses has not been solved, emphasise the scientists, despite able to add another piece to the puzzle.  Data would need very careful interpretation because of the very different evaluation methods in individual countries.

"With the limited evidence available it is neither possible to identify the actual driver of honey bee losses in Europe nor to give a complete answer on the trends for colonies and beekeepers.

This creates an urgent demand for a standardisation of evaluation methods, especially on colony numbers. Such harmonised reliable methods will be the obvious backbone for any research to understand and mitigate honey bee colony losses", adds Dr Settele.