The world is losing its honey bees at an alarming rate - a trend that could prove disastrous for us all....
In the closing months of 2006, when thousands of American beehives were found to be almost entirely devoid of bees ñ victims of a mysterious malady known as Colony Collapse Disorder (CCD). A study across 15 different states of the USA by the Apiary Inspectors of America found that from September 2006 to March 2007, almost a third of all honey bee colonies had collapsed.
This winter it was even worse, with a recode 36% of colonies lost between September and March. Nor is the problem limited to America: large numbers of colonies have been wiped out in Canada, South America, Asia and Europe. In Croatia, five million bees were reported to have disappeared in 48 hours; in Taiwan last year around ten million vanished.
CCD occurs when most of the bees suddenly disappear from a hive ñ leaving it like an apian Mary Celeste ñ with only queens, eggs or pupae (the "brood") and a few immature workers still remaining. The vanished bees ñ strangely never found ñ are thought to die singly far from home.
The phenomenon is odd for various reasons. First, bees never usually abandon a hive until the brood has hatched; their sophisticated in-built navigation system allows them to forage up to three miles from the hive and return safely. Second, when a colony dies, the honey left behind is usually raided by bees from other hives, or by moths and beetles. Yet bees and pests avoid the abandoned hives like the plague. And lastly, the incidence of CCD is very erratic. Some beekeepers report heavy losses while their neighbours maintain healthy hives.
If honey bee populations continue to decline it will, of course, hit honey supplies. But far more disturbing is the effect it could have on plant. Most flowering plants rely on animals to pollinate them, and the honey bee is nature's premier pollinator, with a body perfectly designed to collect and spread pollen, and a work ethic to match: one big colony, containing up to 60,000 worker bees can pollinate millions of flowers in a day. The US Department of Agriculture estimates that about a third of the food we eat benefits directly or indirectly from bee pollination.
Scientists remain puzzled. One study at Pennsylvania State University found that a microbe ñ the Israeli Acute Paralysis Virus, which immobilises bees and kills them ñ was present in all but one of the sick colonies. But researchers believe the virus, along with other diseases found in "collapsed" colonies, may be a symptom rather than the cause. Given the variety of associated diseases, it seems likely there has been widespread damage to the bees' immune system.
Various explanations are advanced. In America, hives are hauled around the country to pollinate crops, and one theory is that the bees' immune systems get damaged in the process. Another sees the cause in the disruptive effects of climate change, while others again trace it to one of two well-known bee diseases: the varroa mite, a virulent blood parasite; or Nosema ceranae, a pathogenic gut fungus. (More fancifully, some even blame mobile phones, which are said to interfere with with bees' navigation systems.)
The impact of all such factors (except the last) is exacerbated by the shrinking size of the gene pool ñ most bee keepers having filled their apiaries with just one type of bee from Italy, renowned for its honey and gentleness. But many beekeepers point the finger at a quite different culprit: pesticides.
Again, it's not quite clear. However, Dave Hackenberg, the US beekeeper widely credited with discovering CCD, thinks that his bees started to abandon their hives after they had been exposed to apple trees sprayed with a new breed of pesticide: a neonicotinoid, an artificial form of nicotine that attacks insects' nervous systems and disorientates them. One such insecticide has been banned in France since the 1990s, when it was blamed for heavy winter bee deaths. However, deaths have not noticeably decreased since then.
Far from it. The first such recorded case was in America 150 years ago, and ever since, large numbers have vanished at intervals throughout North America, Europe and Australia. An epidemic first reported in the Isle of Wight in 1904 wiped out 90% of the UK's honey bee colonies. These losses have been given many different names: disappearing disease, spring dwindle, May disease, or autumn collapse.
What really bothers scientists and beekeepers about the current situation, though, is the fact that it comes on the back of a sustained reduction in bee numbers, resulting from disease, urbanisation, and beekeepers retiring or going out of business. In America, there were 5.9 million maintained colonies in 1947; today there are only 2.44 million; feral honey bees have all but died out. If bees keep disappearing at this rate, it's estimated that there will be none left in the US by 2035.
As in America, beekeeping has taken a nosedive (from 360,000 hives in 1947 to 250,000 today). Officially, CCD hasn't yet hit Britain; but the varroa mite has caused much damage since it arrived in 1992, and there have been reports of suspected CCD cases. This spring, more than 25% of colonies were found dead, compared to 18.2% last year. The environment ministry (Defra) has stepped up investigations, but the British Beekeepers' Association fears not nearly enough is being invested in research.
"If the bee disappeared off the surface of the globe," Albert Einstein is reputed to have said, "then man would only have four years of life left." This may be an exaggeration, but as Alison Benjamin and Brian McCallum explain in their recent book A World Without Bees, if the honey bee did disappear, agriculture as we know it would collapse.
More than 90 commercial crops ñ from apples, peaches and citrus fruits to strawberries and blackberries, to nuts, carrots, broccoli and onions ñ are pollinated by bees. So is cotton and much livestock fodder, such as clover and alfalfa. A study by Cornell University found that bees helped produce $60bn of food around the world - $15bn in the US alone, where many commercial beekeepers take their hives on a five-month tour of the country, pollinating California's lucrative almond trees, for instance, then Florida's citrus trees and Maine's blueberries. Defra estimates that Britain's 250,000 hives contribute £165m to agricultural output.
Without bees, wind-pollinated grasses would continue to grow, but flowers and vegetable beds would be devastated, and there would be far less food for birds and mammals to eat. In southern Sichuan in China, where honey bees were wiped out by insecticides, pear trees have to be pollinated by hand - an immensely labour intensive business.
Article provided by Pest Control Charter