Bee disappearances around the world are puzzling scientists – and worrying those involved in agriculture, reports Farouq Manji
If you ask any number of people with apiphobia, the fear of bees, they might tell you that the mass disappearance of bees isn’t such a bad thing. However, many species – including humans – depend on the pollinising role of bees for their very survival. The word apiphobia is derived from the Latin word ‘apiary’, meaning beehive, and it so happens that all over the world, for no apparent reason, beehives are being found utterly abandoned.
The phenomenon of bee disappearances has been termed Colony Collapse Disorder (CCD), and it has baffled beekeepers and scientists. In over 30 American states, several Canadian provinces and a number of European countries, entire colonies – each with up to 40,000 bees or more – have vanished without a trace.
What is more puzzling is that they have left their Queen, eggs and honey behind – very uncommon behaviour in such social insects such as honeybees. There are no corpses to be found, and no clues as to where the bees have migrated. Strangely, predators of beehives such as wax moths – which would normally relish the opportunity to feast on unguarded honey – will not enter the hives for several weeks or longer.
Historically, bees have been used to pollinate crops since ancient Egypt, when they were sent down the Nile. In America each year, roughly $14 billion dollars worth of crops depend on bee pollination to survive – which include seeded fruits such as apples and oranges.
In Ireland, it is not uncommon for farmers to import bee colonies from mainland Europe to help pollinate crops to improve their yield. Crops such as oilseed rape and strawberries benefit from the active introduction of colonies.
The constant use of bees in an ever-expanding and demanding industry, however, takes its toll on the colonies. Forcing bees to continuously visit commercially cultivated crops exposes them to pesticides, parasites and other pathogens, as well as causing them the stress of constantly being shipped around. Since their natural habitat has been taken away, they are often undernourished, feeding only on one of several crops rather than the multitude of plants they would encounter in a natural habitat.
All of these stresses are likely to weaken their immune system, forming the basis of one of several theories that have been put forth to explain this strange behaviour. One theory portends that all of these stresses are making the bees more susceptible to viruses and parasites such as the varroa mite.
A predominant theory is that pesticides, specifically a newer type referred to as neonicotinoids, are largely responsible for CCD. These pesticides were partially banned in France in 1999, and have been banned in other European countries intermittently over the last decade. Research indicates that in high doses, these pesticides can interfere with the navigation system in bees, which relies on a complex array of inputs, including the position of the sun, the magnetic field of the earth and the unique scent of the hive. These pesticides have also been the focus of a new documentary released in the UK, which attempts to draw a connection between the use of these pesticides and CCD.
One of the principle manufacturers of these products, Bayer CropScience, denies the association between CCD and their product, and roundly refutes the claims made in the film. The film is slated to be released outside of the UK in the near future.
There are less credible – and plainly ludicrous – theories as well. One is that Osama bin Laden has somehow planned and executed a honeybee massacre to devastate American agriculture. Another, slightly more credible, is that genetically modified crops containing a specific pesticide are killing bees. And one study suggesting mobile phone radiation might be involved, was blown out of proportion and became a media frenzy in America.
One of the most intriguing theories revolves around the discovery of a number of newly discovered viruses, which have been found to affect domesticated bees. One of these, the Israeli Acute Paralysis Virus (IPAV) causes paralysis and bizarre behaviour in bees, however there is no conclusive research to suggest a strong association between it and CCD. Furthermore, some have postulated that viruses carried by Varroa mites may have become more virulent to bees – maybe because of their weakened immune system.
It has therefore been suggested that a new strain of virus may have infected bees, and are causing these mass desertions. Most likely, it is the combination of one or more of the above factors, plus the inordinate stress places on bees, that create the specific circumstances for CCD. Others however, argue that the only reason new viruses are showing up in bees is because their immune systems are being weakened by something larger and more sinister.
It is likely that it will take years before any convincing evidence is found to discern its cause. In the meantime, most experts are hoping that it is not due to an infectious disease – otherwise the picture may look very bleak indeed.
Mass disappearances have occurred before, and have been dated back to the 1800s, but their causes have never been fully determined. Most recently they were reported in the 1920s and 1960s. Is it possible that this phenomenon is part of a natural cycle? If so, it must be taken into account just how far this might go – to date, some have estimated that approximately 34 per cent of American bees have been affected by CCD.
Dr Maria Spivak of the University of Minnesota agrees that bees are largely quite stressed, and believes that they provide a sensitive reflection of the environment and our impact upon it. When they collect and return food to their nests, they concentrate the contaminants in the foods and create a toxic living environment.
Pollinating bees are responsible for the growth of up to one third of the world’s food supply. Perhaps bees are serving as a microcosm of the general world we live in – and if this is the case, it makes it all the more important to understand what is happening to our honeybees.