The A to Z on why it's a tough time for bees

12:17pm Thursday 7th August 2008

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WE all know honey bees produce honey, but pollination is another important role for all types of bees. Stuart explained 84 per cent of European crops species rely on insect pollination along with 80 per cent of wild flowers. Bees, which can be divided into three broad types, play a valuable role in this.

In the UK, we have one species (but many varieties) of honey bee, around 20 species of bumblebees and some 240 species of solitary bees. These are all subject to different pressures which may cause a decline in numbers.

Honey bees are valued for their honey in Europe but, in the USA, their primary use is as pollinators of crops and fruit trees.

Stuart explained Colony Collapse Disorder (CCD) has been blamed for the loss of many colonies of honey bee in the USA.

"There are a whole stack of things which can cause a colony to collapse," said Stuart, "Even a careful beekeeper can lose a colony over winter." The causes of this disastrous condition are not understood, but Stuart believes the many stresses the bees are placed under may weaken their immunity against other pests and diseases.

"Part of the problem in the USA is that pollination is the most important reason for keeping bees, so they are subject to stresses such as being moved around the country to pollinate crops.

"It's a really big business and, for one packet of almonds you buy, 20 per cent of the cost comes from pollination."

"Add to this a combination of poor bee husbandry, limited diet, pesticide exposure and Varroa mites and we have a perfect storm. As far as we know, there is no evidence for CCD in Europe, however we do have the parasitic Varroa. This only affects honey bees and can cause massive losses.

"There have been scare stories in the national press honey bees will be extinct in ten years time, but this is unlikely. They are managed and so the chances are remote.

"However, there have been definite declines in bee keeping in some parts of Europe."

Of the 20 or so species of bumblebees in the UK, only around six are common and at least two became extinct in the last century.

Several other species are scarce or seriously threatened.

Stuart puts the bumblebee decline down to massive and widespread habitat loss caused by an increase in urbanisation and changes in agricultural practice, which may reduce the amount of suitable forage for the bee colonies.

As for the solitary bees, many are so small they are difficult to keep an eye on, but groups such as the Bees, Wasps and Ants Recording Society which use keen amateur entomologists are essential because they provide a lot of data for professional scientists to analyse.

"There is a clear role for amateurs to get involved - they provide critical data to allow professionals to do their work," said Stuart, who works as a researcher for Reading University.

There are clear changes in both solitary and bumblebees in Europe, with more losers than winners. Common species are getting commoner and rarer species are getting rarer.