The disappearing bees was a great Doctor Who storyline.

With the universe teetering on the abyss - courtesy, naturally, of the Daleks - and the Doctor literally lost in space, he suddenly came to the conclusion that the bees had not been disappearing at all, but fleeing the Earth because they had sensed it was time to make a swift exit.

Dig deep into the internet and similar stories abound; the bees are getting out before doomsday.

That there are fewer domestic honeybees and their feral cousins, wild bees - bumblebees - worldwide is not in dispute. The reasons why, though, are much more prosaic.

"It's the varroa mite," said Peter Inson. "It came into the UK, Australia and New Zealand about 15 years ago, probably on the bodies of live bees brought in illegally. The mite lives on the bees' body fluids and eventually kills them."

The mite attacks all bees, both domestic and wild, and can decimate hives. While beekeepers can ensure their honeybees take anti-varroa drugs via a sugary paste, bumblebees are on their own.

"But the mites are already developing a resistance," said Mr Inson, "so scientists are having to adapt the drugs. Still we have learnt a lot about how to cope with the problem facing domestic bees. Unfortunately, that is not helping the bumblebees. There are fewer feral colonies today than there were a decade ago."

Mr Inson is a beekeeper (an apiarist) and a member of Colchester Beekeepers' Association. He has seven hives in the garden of his home at East Mersea.

Each hive contains a single colony and the number of bees in the colony can be as high as 50,000 in the summer, when the bees are actively collecting pollen and making honey, to no more than 4,000 in the winter.

Mr Inson doesn't just keep bees to sell honey. He is finding he is more and more in demand from local farmers who want his domestic bees to pollinate their crops because there are fewer bumblebees. The wild bee may be more attracted to crop flowers than the honeybee (honeybees prefer nectar-rich plants) but where needs must, the honeybee will rise to the occasion.

"My bees have already pollinated bean plants," said Mr Inson, "and the farmer was so pleased he is thinking of planting borage and hiring my bees again."

It isn't only the varroa mite which has reduced bumblebee numbers. Intensive farming and a cut in the number of insect-pollinated crops (more cereal crops, fewer bean crops) have also led to decline. Three of the UK bumblebee populations are already extinct and another nine are on the endangered species list.

Brian Finnerty, spokesman for the East Anglia branch of the National Union of Farmers (NFU), said pollination by bees is worth £200 million a year to the agriculture and horticulture industries.

A further decline in bumblebee numbers could have a serious economic impact on the farming industry, which is why the Department for Food and Rural Affairs' (Defra) National Bee Unit is looking at ways to give the bumblebee a fighting chance.

"They (bumblebees) play a very important role," said Mr Finnerty. "They are the best pollinators. That is why so much effort is going into trying to reverse their decline."

Then there is the UK's intensive house-building programme, particularly in north Essex and the Thames Gateway (east and south-east London, parts of Kent and Essex - 120,000 new homes by 2016) which conservationists claim is "decimating" the bumblebees' habitat.

Ben Darvill, of the Bumblebee Conservation Trust, revealed four types of bumblebee, amongst the most endangered species in the UK, thrive on wild flowers in the Thames Gateway area.

"We recognise they are rare and yet they (the Government) still seem determined to let developers build on these sites," said Mr Darvill. "Without bumblebees you are talking about reduced crop yields and sweeping changes to the countryside."

Meanwhile, America has a more perplexing bee problem. Colonies there really are disappearing. There is even a name for it - collapsing colony disorder (CCD) - and it is getting worse.

"There is no explanation for it as yet," said Mr Inson. "The bees just abandon their hives and vanish. There is no sign of disease, no sign of anything.

"Oh, there have been theories. Climate change hasn't been dismissed, but the notion that electrical impulses from mobile phones were affecting the bees' navigation was quickly dismissed."

Which makes it all very definitely more Doctor Who than Defra.

WHY ARE BUMBLEBEES IMPORTANT?

  • Bumblebees work on plants with no nectar, so play a crucial role in the pollination of farm flowers and vegetables
  • The farming industry relies heavily on insect pollination. Few, if any, bean flowers, for example, would set pods unless they were pollinated by insects, particularly bumblebees, which the Department for Food and Rural Affairs' (Defra) National Bee Unit says are the most efficient pollinators
  • Many apple, pear and plum trees rely on bumblebees for good harvests.

BUMBLEBEES AT RISK

Britain and Ireland have 25 native species of bumblebee.

Five are currently listed in the UK Biodiversity Action Plan because of their rapid decline - bombus distinguendus (great yellow bumblebee), bombus humilis (carder bumblebee); bombus ruderatus (large garden bumblebee), bombus subterraneus (short-haired bumblebee) and bombus sylvarum (shrill carder bee).