Posted 16 August 07
A killer disease continues to wipe out honey bee colonies across America, and British beekeepers say that their hives are now starting to succumb. While everything from pesticides to mobile phones is being blamed, Richard Grant joins investigators hunting for the real culprit
'These are some of the sickest bees in America,' says Dennis van Engelsdorp, helping me into a beekeeper's suit but wearing just a T-shirt, jeans and sandals himself. A scruffy blond Dutch-Canadian, 37, and a casual veteran of many thousand bee stings, he is one of the lead scientists investigating the mysterious die-off of honey bees in America. He has been inspecting hives around the country, bringing back samples for the various laboratories studying the phenomenon and keeping some of the worst cases under observation here by his cabin in the woods of central Pennsylvania.
He opens the bear-proof fence and works the bellows on his smoker, a nozzled canister full of burning leaves. Smoke makes bees less aggressive. It disrupts the scent alarms sent by the guard bees, instructing the others to come out and attack the intruders. Instead they start gorging themselves on honey, on the assumption that a forest fire is about to destroy the hive and they'll need the extra energy to build a new one. He puffs some smoke into the first hive, takes off the lid and lifts out one of the frames. 'Look at this,' he says, 'This should be covered in bees. There's plenty of honey, pollen and brood [eggs, larvae and pupae] but hardly any adults, just these few small groupings. They're abandoning their young and their food stores, leaving the colony and just disappearing.'
Honey bees cannot survive outside the sophisticated social structure of the colony, with its guard bees and nurse bees, heating and cooling teams, cleaning squads, foragers, comb-builders, honey-processors - all of them female and all of them sisters, daughters of the same queen, communicating with each other with scents and through dances. The males, or drones, are big, hairy, clumsy and stingless. They don't dance and their only function is to mate with the queen, after which they die.
The investigators have no doubt that the disappearing bees are dying but they almost never find the dead bodies, which doesn't make it easy to determine what's causing the phenomenon. For want of a better term, they're calling it Colony Collapse Disorder (CCD), and since last November it has ravaged a quarter of America's 2.4 million beehives. In mild cases 35 per cent of the bees disappear. In severe cases an apparently healthy colony of 30,000 bees will empty itself out completely in a few days. 'Some people think their navigation systems are affected and the bees are getting lost on their way back to the hive,' van Engelsdorp says. 'I think the bees know they're sick and they're leaving the colony so they don't infect the others. But that's just a theory. At this stage it's all just theory although we are narrowing down the possible explanations.'
He lifts the lid off another hive. This one is completely deserted but still contains a good supply of honey and an intact comb. 'It's been like this for more than two weeks,' he says. 'Normally, within a day or two of bees leaving a hive, other bees come in to rob the honey and small hive beetles and wax moths start eating the comb. But this hasn't been touched and it's something we see a lot with CCD. The toxin or the pathogen or whatever it is must still be giving off a scent. These insects can detect it but as yet we can't.
A third hive contains only the slender elegant queen, still laying eggs, and a small surrounding cluster of her newly hatched offspring. 'It doesn't seem to affect the queens. Look, she's really trying but the adults are leaving faster than she can replace them. Why? That's the big question.'
For American agriculture it's a $14 billion a year question. That is the estimated value of the food crops pollinated by honey bees every year - 90 different fruits and vegetables, or one third of the American diet. They also make honey, of course, but in economic terms that's strictly a sideline activity, valued at $157 million a year. 'Without bees for pollination,' vanEngelsdorp says, 'we'd basically be eating grains and meat.'
Colony Collapse Disorder has generated enormous public interest and media coverage in America and dozens of theories have been proposed, including some predictable nonsense: the bees are experiencing rapture and ascending to heaven; aliens are abducting the bees; the military is altering the earth's electro-magnetic field in top-secret experiments; it's a plot by Osama bin Laden to destroy American agriculture.
GM crops have come under more serious scrutiny. So have the possible effects of climate change, air pollution, chemicals in the water and radiation waves from power lines and mobile phones. The main suspects, however, are a new contagious disease, damage from pesticides, and the stress on bees from being transported long distances and fed on artificial syrups and protein supplements. Most commercial beekeepers in America live as nomads, migrating from one flowering crop to the next with their hives stacked up in 18-wheel juggernauts. These were the first to suffer from CCD and the hardest hit, although it is also affecting some small organic beekeepers who don't take their bees on the road.
There have been unconfirmed reports of CCD in Canada, Brazil, Guatemala, Thailand, Switzerland, Spain, France and Britain, where the contribution of honey bees to agriculture and horticulture is estimated at £1 billion a year, and absolutely invaluable when it comes to the natural environment. The Department for Environment, Food and Rural Affairs (Defra) is insisting that CCD is not in Britain and that the sudden dramatic disappearances that some British beekeepers saw last winter were caused by varroa mites - virus-spreading Asian parasites that have killed a third of British bees and nearly half of American bees since the early 1990s.
When varroa destroys a colony, you usually find dead and dying bees in and around the hive, a high incidence of deformed wing virus and a lot of varroa mites, which are visible to the naked eye and about the size of a pinhead. If bees were human-sized and you scaled up the proportions, varroa mites would be the size of dinner plates, immovably attached and sucking your blood with their filthy disease-ridden mouthparts. John Chapple, the head of the London Bee Keepers Association, is all too familiar with varroa but last winter he and some of his members in west London found something they had never seen before: abandoned hives with no dead bees left behind and low mite populations. As did some beekeepers in other parts of England and Scotland.
'Marie Celeste syndrome is what we've been calling it,' Chapple says. 'I don't know if it's CCD or varroa-related but either way I think the Government should be investigating it. A third of our members lost all their bees last winter. Our feeling is that DEFRA doesn't want to admit there's something new going on because then it would be forced to do something.'
The total budget for research into bee health in this country is now less than £200,000 a year, and DEFRA has recently laid off some of Britain's leading bee scientists and closed down the bee health research centre at Rothamsted, Hertfordshire. There have been only a few isolated cases of these mass disappearances, and even if they are CCD, no one knows what causes it or what can be done about it, so why not sit back and let the Americans do the work? 'We remain in touch with US experts who are looking into the causes of CCD,' a DEFRA spokesman said, 'so we can then establish how it can be prevented here.'
Dennis van Engelsdorp's assistant is a heavily muscled young man with extraordinarily precise fingers. His name is Mike Andree and he is performing a bee autopsy in a laboratory at Pennsylvania State University. The bee was taken from a collapsing colony in Florida and preserved in alcohol. Using a tiny scalpel, he slits open its sides, peels back the husky scales on its abdomen and examines its insides under a microscope. He knew almost nothing about bees when he started this job a few months ago, but like most people who spend time around these remarkable insects, he has become charmed and intrigued by them and worried about their future. 'We've been collecting samples from CCD colonies and healthy colonies to compare them,' he says. 'But when you get them under the microscope, nearly all the bees look sick. I've done a thousand of these autopsies in three months and I tell you, it's really difficult to find a healthy-looking bee.'
This one, like so many CCD bees, has a shocking amount of disease symptoms. Its venom sac and sting gland are swollen and discoloured, indicating infection. Its kidneys are blackened, its intestines are scarred and it was clearly suffering from terrible constipation. 'The contents of its rectum should be soft but this is hard, undigested and really packed in there. We see this a lot. These bees can't relieve themselves but we have no idea why or what it means.'
There are also white nodules and long blue or green strands showing up inside some bees. 'We're still scratching our heads about those,' vanEngelsdorp says. One thing that's clear is that the immune systems in CCD bees are severely compromised and one theory is that CCD is analo-gous to Aids. Secondary infections from bacteria and fungus are taking advantage of their weakened immune systems and leaving this blackening and scarring on their internal organs. But what is attacking or degrading their immune systems?
Andree leans towards an environmental explanation. Before bees, he was studying the effects of polluted stream water on amphibians and saw some similarities. 'I've come to think that all the pollutants and insecticides we're putting into the environment are having an effect on the bees. Maybe they're building up to a point where the bee's immune system collapses and then all these other infections come in. But that's just my guess and I'm no expert.'
GM crops, fingered by many environmental activists as a cause or a contributing factor, are no longer under investigation, for the simple reason that the states with the most genetically modified crops - such as Illinois, where more than 75 per cent of the corn is GM - have almost no CCD. May Berenbaum, a professor of entymology at the University of Illinois, points out that bees do not pollinate any GM crops grown in America (mostly grains) and she knows of no biological mechanism whereby GM crops would be able to affect bees.
Nor are mobile phones to blame, although this theory is now firmly embedded in the folk culture and shows no signs of going away. The Independent was the first English-language newspaper to report on a German experiment indicating that radiation waves from mobile phones were interfering with the homing abilities of honey bees and might be responsible for CCD. From there the story replicated itself unchecked into all the British newspapers, and then around the world.
In fact the experiment was with the base unit of a cordless telephone and its results were entirely inconclusive, as the two German scientists, Jochen Kuhn and Stefan Kimmel, have been trying to explain ever since. American beekeepers, meanwhile, have developed an arsenal of jokes on the subject. Why should you keep mobile phones away from your bees? Because they're social insects and they'll bankrupt you with the phone bills. Because they'll only pollinate Blackberrys. Because they'll start texting instead of doing the waggle dance (a figure-of-eight dance that bees use to communicate the location of a good nectar source, based on the angle of the sun and accurate from 100 metres).
Still replicating itself through the global media machine is an ominous quotation by Einstein: 'If the bee disappeared off the surface of the globe, then man would have only four years of life left. No more bees, no more pollination, no more plants, no more animals, no more man.' In fact, Einstein never said or wrote any such thing, as several scholars have confirmed. According to snopes.com, a website devoted to quashing internet rumours, the quote first appeared in 1994 and was fabricated by the National Union of French Apiculture to bolster its calls for tariff protection against cheap honey from China.
The content of the quote is also problematic. Does it refer to the 12 species of honey bee, or all 30,000 species of bee that are thought to inhabit our globe? There would indeed be catastrophic consequences if they all disappeared, but bees are not the only pollinators and some plants, animals and humans would survive.
Another widespread misunderstanding is that vanishing bees are something new. Looking back through the literature, van Engelsdorp has found references to sudden mysterious disappearances dating from 1869. In 1923 a bee handbook mentioned a 'disappearing disease'. In 1965 something similar was noted and called 'fall dwindle'. He has witnessed bees crawl away from hives en masse because of varroa, and fly away in droves because of amoebic cysts and the depradations of a fungus called nosema. What the British call Marie Celeste syndrome, he says, is usually caused by one of these three agents. 'But if you've got low varroa, and you test for amoeba and nosema and they're not there, and the population is collapsing dramatically, and other bees and insects are avoiding the hives - which has never been mentioned before in the literature - then you've got CCD and I'm almost 100 per cent positive it's being caused by something new.
Dave Hackenburg, a former president of the American Beekeeping Federation, is a 58-year-old Pennsylvanian who drives up and down the country with some or all of his 3,000 hives in a fleet of juggernauts. Last November he checked on a group of 400 hives he had taken to Florida a month previously. All but 40 were empty. 'It was the most phenomenal thing I'd ever seen,' he says.
As the migratory beekeepers moved north for apples in Pennsylvania, blueberries in Maine, cranberries in Massachusetts and west for almonds in California, more and more of them began reporting catastrophic disappearances. One of Hackenburg's friends lost all but five of his 1,400 hives and had to give up the business. Hackenburg's losses added up to $460,000 in missed pollination fees, lost honey and the cost of buying replacement bees. 'I'm still going and I've got good summer bees at the moment,' he says. 'But there's a lot of beekeepers quitting or the bank's selling them out. If we get another winter and spring like the last one, there's going to be a whole lot more of them going out of business.'
The more high-tech, profit-driven and monocultural American agribusiness has become, with laser-levelled fields stretching across the horizon, all growing the same crop, the more dependent it has become on these few hundred migratory beekeepers. Bees cannot survive in a place where only one crop grows. Neither can other pollinators. Except for the few weeks a year when that plant is in bloom, there is nothing for them to eat. Pollination fees are already increasing because of a shortage of bees. If the CCD die-offs continue and more beekeepers go out of business, the effects on agriculture will be rapid and dramatic.
The most profitable crop in California these days (apart from illegally grown marijuana) is almonds, worth $2.34 billion a year. In the state's Central Valley the almond orchards cover more than half a million acres. Every February more than half the honey bees in America - 10 billion or so - arrive by truck to pollinate the pink blossoms. The profits from almonds, buoyed by recent studies suggesting health benefits, are so irresistible that farmers are planting more and more trees, but already there is a shortage of bees and a black market has sprung up.
Unscrupulous beekeepers are donning their suits and veils at night, sneaking into orchards, stealing hives and renting them to desperate farmers who didn't manage to procure any bees by legal means. Detective Frank Swiggart of the Modesto County Agricultural Crimes Unit has set up aircraft patrols and is putting GPS locators on hives, but so far he has arrested just one offender, who stole several thousand hives.
Dennis van Engelsdorp visited the California almond groves for the first time this year. 'I looked out over this huge wide valley and thought it was covered in snow. Then I realised it was beehives. It was an incredible sight and also sobering because it's the perfect scenario for spreading disease.'
The lifestyle of the average modern honey bee in America, living on the road in overcrowded hives stacked up in juggernauts, short on fresh air and subject to overheating, fed on corn or sucrose syrups and protein supplements to keep them going between nectar-rich crops, treated with miticides, moving relentlessly from one crop to the next - isn't this a profoundly unnatural way for a bee to live? Isn't this enough to stress them out and compromise their immune systems?
'If that's your argument you've got to explain why the organic, non-migratory guys are also getting CCD,' van Engelsdorp says. 'You've got to explain why it's happening now and not 10 or 20 years ago because this is nothing new. You've got to explain why some migratory guys have had devastating losses and others have had no losses at all.'
Most migratory beekeepers are convinced that pesticides are the culprit, and in particular a class of insecticides called neonicotinoids. Launched by Bayer in 1994 under the name Imidacloprid and banned in France after they were implicated in a massive die-off of honey bees, they are based on a synthetic form of nicotine, safe for humans and designed to kill aphids and other pests by disrupting their nervous systems. 'These insecticides are everywhere in America,' Hackenburg says. 'Agricul-ture loves them because they work on aphids and people are using them on golf courses, lawns, gardens, flea collars for pets. I think they're having sub-lethal effects on the bees, breaking down their immune systems and causing memory loss.'
Maryann Frazier is the scientist in charge of investigating these pesticides and their possible connection to CCD. 'We know they're toxic to bees and their use has greatly increased in the last two years,' she says. 'We're finding them in pollen samples taken from inside beehives, at varying levels. What this means we don't know because the hives with the highest levels of these pesticides are often having no trouble, and the hives with very low levels are often collapsing, so we can't make the connection.' It is worth noting that French bee populations have not rebounded since neonicotinoids were banned there.
Frazier thinks these insecticides, along with the herbicides, fungicides and miticides they are finding in hives, are probably having an adverse effect on bee health in general, and she has begun experiments to measure what these effects might be. But neither she nor any of the other 15 scientists involved in the investigation think that pesticides alone are causing CCD.
One reason why is an experiment conducted by van Engelsdorp. He imported some packages of bees from Australia, where CCD is unknown. He put one group into recently abandoned CCD hives. He put a second group in CCD hives that had been fumigated with concentrated acetic acid, a hive cleaner. He put a third group into hives that had been irradiated, a process that kills all living organisms and potential pathogens but does not break down chemical toxins. The bees in the untreated abandoned hives developed all the symptoms of CCD. The bees in the fumigated hives held their own. In the irradiated hives, the bees were flourishing. 'It definitely points towards a biological cause,' he says. 'And probably a new or newly mutated pathogen - a contagious virus, bac-terium or fungus that is making bees sick.'
As to what that pathogen might be, we may know more when the results of an experiment at Columbia University are peer-reviewed and published. Fortuitously, the honey bee's genome was sequenced last year before the first outbreak of CCD, and a virologist called Ian Lipkin and a bee scientist called Diana Cox-Foster have been grinding up dead bees and comb material and running it all through a DNA sequencing machine. It's a very expensive, time-consuming technology that identifies all the living organisms in the ground-up material by their DNA. By subtracting the honey bee genome, you can then see what's left, including bacteria, viruses and fungi. 'We have found some pathogens that are highly likely to be linked to CCD,' Cox-Foster says. 'They may be causing it but it's too early to say. We've found them where no CCD developed so there might be additional triggers. The next stage is to test these pathogens on bees in the laboratory and see how they react.'
It is a muggy mid-summer evening in rural Pennsylvania and some 70 beekeepers are gathered for an outdoor meeting and a presentation by Dennis van Engelsdorp about CCD. The air is buzzing with bees from the nearby hives and talk of pathogens, pesticides, varroa mites, tracheal mites, air pollution, nutrition, methods of transportation, climate change, GM crops, the ways queens are bred, the way modern bees are bred for size not hardiness.
The most obvious explanation of CCD is the perfect storm theory, that all these different elements have come together and pushed the bees into collapse. It has many proponents here among the beekeepers and in the media but none of the bee scientists I spoke to gave it much credence. 'We know that varroa and poor nutrition weaken bees' immune systems and those could certainly be important factors in conjunction with a pathogen,' van Engelsdorp says. 'But there's this tendency to just pile up a big heap of all the possible explanations and present that as the answer. It's a simple explanation but the simplest explanation is not always the right one.'
Before I leave he wants to show me a flourishing hive and make sure I understand what's at stake - not just the future of agriculture and honey production and all the birds and wild animals that depend on flowering plants but the marvel of bees themselves. He takes off the lid and starts lifting out the frames and there is a waggle dancer, shaking her abdomen in excitement and turning figure-of-eights, and van Engelsdorp is explaining how the workers collect water and fan their wings over it to cool the hives, and bring their bodies together to warm it. 'Look at that,' he says, smiling proudly on their behalf, oblivious to the bee crawling on his neck. 'Is there anything more beautiful than to see all these sisters working together in harmony?