Where have all the flowers gone?/Long time passing/Where have all the Bees gone?/Not so long ago not so long ago/Where have all the flowers gone?/Bees have picked them every one/When will we ever learn?/When will we ever learn?

All apologies to Pete Seeger; however his Vietnam Era anti war song could well serve as an anthem for the American beekeeper.

Researchers are scrambling for clues, any clues, into the recent, baffling disappearance of honeybees across the United States, a potentially catastrophic trend that threatens the hundred or more food crops dependent on bees for pollination.

Unless someone or something stops it soon, the mysterious killer that is wiping out many of America’s honeybees could have a devastating effect on the country’s dinner plate, perhaps even reducing its people to a glorified bread-and-water diet.

The almond trees are blooming and the bees are dying, and nobody knows why. All up and down California’s vast San Joaquin Valley, nearly 2,500 square kilometers of small nut trees arranged in laser-straight rows are shaking off the cobwebs of winter.

They’re gearing up once again to produce nearly half a billion kilograms of nuts, worth US$3 billion to the U.S. economy.

The trees cannot produce the bounty on their own, however. They need bees – a million hives worth – trucked in from nearly forty U.S. states to move pollen from one tree to another, fertilizing the blooms in the largest managed pollination event on Earth.

But even as the beekeepers reap record fees for renting their hives, their livelihood is now threatened by the largest loss of honey bees in the history of the industry.

Since October 2006, 35 per cent or more of the United States’ population of the Western honey bee (Apis mellifera) – billions of individual bees – simply flew from their hive homes and disappeared.

What’s causing the carnage, however, is a total mystery; all that scientists have come up with so far is a new name for the phenomenon – Colony Collapse Disorder (CCD) – and a list of symptoms.

In hives hit by CCD, adult workers simply fly away and disappear, leaving a small cluster of workers and the hive’s young to fend for themselves.

Adding to the mystery, nearby predators, such as the wax moth, are refraining from moving in to pilfer honey and other hive contents from the abandoned hives; in CCD-affected hives the honey remains untouched.

The symptoms are baffling, but one of the emerging hypotheses is that the scourge is underpinned by a collapse of the bees’ immune systems. Stressed out by cross-country truck journeys and drought, attacked by viruses and introduced parasites, or whacked out by harmful new pesticides, some researchers believe the bees’ natural defenses may have simply given way.

This opens the door to a host of problems that the bees can normally suppress.

What’s surprising is that mysterious declines are nothing new. As far back as 1896, CCD has popped up again and again, only under the monikers: ‘fall dwindle’ disease, ‘May dwindle’, ‘spring dwindle’, ‘disappearing disease’, and ‘autumn collapse’.

Even the current outbreak has possibly been going on undetected for two years, according to the CCD Working Group – a crack group of U.S. researchers from institutes including the Pennsylvania State University and University of Montana, who are trying to unravel the mystery.

What has made the members of the Working Group – as well as conservationists, beekeepers, and farmers – really sit up and notice is the scale of this year’s decimation; something in the environment has allowed CCD to reach an unprecedented scale that threatens the very survival of the pollination industry.

“We have never seen a die-off of this magnitude with this weird symptomology,” said Maryann Frazier, a bee researcher at Pennsylvania State University. “We’ve seen bees disappear over time and dwindle away, but not die-off so quickly.”

A problem preventing clear identification of CCD is that honey bees are already under threat from manifold foes.

Even without CCD, the number of managed hives in the U.S. has dwindled by nearly 50 per cent since the industry’s peak in the 1970s. The main culprit for the die-offs is a tiny Asian mite. Known as Varroa destructor to scientists and the ‘vampire mite’ to beekeepers, these tiny parasites – circular, crab-like arachnids about the size of a bee’s eyeball – have been quietly parasitizing the Asiatic honey bee (Apis cerana) in Southeast Asia for millennia.

Some time in the early 1980s, though, the mites hitched a ride to America and hopped on new hosts – spreading like wildfire throughout the defenseless Western honey bee population with the help of migratory beekeepers who obligingly trucked them around the country.

The mites suck the vital juices out of both developing and adult bees, and left unchecked can kill a hive within 12 months.

In addition to the damage that the mites do themselves, they also spread viruses. Furthermore, the mites appear to assist the viruses by somehow sabotaging the bees’ immune system.

“There’s something about a mite feeding on a bee that just knocks its immune system out. [Then] the viruses can take over,” said Eric Mussen, a bee researcher at the University of California, Davis.

But mites and their viruses have been infecting U.S. honey bees for nearly 30 years. What has experts worried is that CCD kills bees even more efficiently than mites – destroying a healthy colony in a matter of weeks.

As if having its bodily fluids sucked out by a parasite wasn’t enough to weaken a bee, some suspect its immune system is also under attack from plain old stress.

Just as humans fall ill more readily after draining tasks or emotional upheavals, Mussen said stress is a sure-fire way to compromise bee immunity too.

The lives of commercial honey bees are filled with stress. A typical year for a hive might entail up to five cross-country truck trips, chasing crops to pollinate and clover fields to make honey in. Banging the bees around during cross-country journeys can take a heavy toll.

“Some of the beekeepers you talk to will tell you that they’ll lose 10 per cent of their queens” on every trip, Mussen said. Besides transportation stress, many of the hardest-hit beekeepers have reported that their hives underwent extraordinary stresses like drought, overcrowding, or famine, in the months before die-offs occurred.

Stress alone won’t kill a bee, but Mussen thinks that it’s just one more factor conspiring against them. “It’s the knocking down of the immune system, it’s having mites around – everything is just piling up – they haven’t got much of a chance.”

Pesticides are designed to kill bugs and other pests on crops without causing harm to humans or the environment. But in a never-ending biological arms race, miscreant insects develop resistance to new pesticides nearly as fast as chemists can create them.

In this tit-for-tat exchange, scant attention is paid to effects that new pesticides have on beneficial insects like honey bees.

While many pesticides are downright lethal to bees, some new studies have pointed to other strange effects found at low doses. For example, low doses of new compounds called neonicotinoids might be interfering with bee minds. Potentially, this prevents them from remembering their colony’s location and causes them to get lost and never return.

According to Pennsylvania State University entomologist Diane Cox-Foster, another possibility is that neonicotinoids are a factor in impairing bee immunity.

Yet another hypothesis is that sick adult bees may be self-sacrificing: flying away to die in order to protect the hive from further infection.

When the Working Group first examined samples of CCD-killed bees from across the country, one factor they found in common was fungal growth in the bees’ guts. The fungi may be from the genus Aspergillus, a group of fungi that produce toxins which can kill young adult bees.

Studies published in the past have reported that bees infected with the fungus fly away from the colony to die.

Not that Aspergillus is the only possibility. “We’re asking if there is anything new that may have been brought in accidentally,”said Cox-Foster. “We know that there are a couple of potential routes for introduction of new pathogens.”

When a colony is weakened other bees or insects usually move in to take advantage of the gap and score a free lunch in the form of honey.

Not so in CCD-killed hives; wax moths and other predators stay away, at least for much longer than they would normally.

According to Cox-Foster, it could be that insects’ keen sense of smell may be keeping them away from dangerous chemicals present in the dead hive. “We know that insects are very good at detecting chemicals in their environment.

There are studies that have taken caterpillars and shown that they’ll actually feed around a droplet of pesticide on a leaf because they can detect it”

“One of our hypotheses is that the fungus itself is producing toxins that are being detected by the other insects. Likewise, it could be one of these environmental contaminants [like pesticides],” she said.

That’s as far as the research detectives have gotten to date. Are bees, under stress from many sources, succumbing to pressure from new pathogens or chemicals? Between mites, viruses, fungi, stress and new pesticides, the insects are under threat like never before.

.Honeybees do not just make honey; they pollinate more than 90 of the tastiest flowering crops such as: apples, nuts, avocados, soybeans, asparagus, broccoli, celery, squash and cucumbers and along with lots of the really sweet and tart stuff, too, including citrus fruit, peaches, kiwi, cherries, blueberries, cranberries, strawberries, cantaloupe and other melons.

In fact, about one-third of the human diet comes from insect-pollinated plants, and the honeybee is responsible for 80 percent of that pollination, according to the U.S. Department of Agriculture.

Even cattle, which feed on alfalfa, depend on bees. So if the collapse worsens, Americans could end up being “stuck with grains and water,” said Kevin Hackett, the national program leader for USDA’s bee and pollination program.

“This is the biggest general threat to our food supply,” Hackett said.

While not all scientists foresee a food crisis, noting that large-scale bee die-offs have happened before, this one seems particularly baffling and alarming.

U.S. beekeepers in the past few months have lost one-quarter of their colonies — or about five times the normal winter losses — because of what scientists have dubbed Colony Collapse Disorder.

The problem started in November and seems to have spread to 27 states, with similar collapses reported in Brazil, Canada and parts of Europe.

Scientists are struggling to figure out what is killing the honeybees and early results of a key study this week point to some kind of disease or parasite.

Even before this disorder struck, America’s honeybees were in trouble.

Their numbers were steadily shrinking, because their genes do not equip them to fight poisons and disease very well, and because their gregarious nature exposes them to ailments that afflict thousands of their close cousins.

“Quite frankly, the question is whether the bees can weather this perfect storm,” Hackett said. “Do they have the resilience to bounce back? We’ll know probably by the end of the summer.”

Pulitzer Prize-winning insect biologist E.O. Wilson of Harvard said the honeybee is nature’s “workhorse — and we took it for granted.”

Beginning this past fall, beekeepers would open up their hives and find no workers, just newborn bees and the queen. Unlike past bee die-offs, where dead bees would be found near the hive, this time they just disappeared. The die-off takes just one to three weeks.

USDA’s top bee scientist, Jeff Pettis, who is coordinating the detective work on this die-off, has more suspected causes than time, people and money to look into them.

The top suspects are a parasite, an unknown virus, some kind of bacteria, pesticides, or a one-two combination of the top four, with one weakening the honeybee and the second killing it.

A quick experiment with some of the devastated hives makes pesticides seem less likely. In the recent experiment, Pettis and colleagues irradiated some hard-hit hives and reintroduced new bee colonies. More bees thrived in the irradiated hives than in the non-irradiated ones, pointing toward some kind of disease or parasite that was killed by radiation.

The parasite hypothesis has history and some new findings to give it a boost: A mite practically wiped out the wild honeybee in the U.S. in the 1990s. And another new one-celled parasitic fungus was found last week in a tiny sample of dead bees by University of California San Francisco molecular biologist Joe DeRisi, who isolated the human SARS virus.

However, Pettis and others said while the parasite nosema ceranae may be a factor, it cannot be the sole cause. The fungus has been seen before, sometimes in colonies that were healthy.

Recently, scientists have begun to wonder if mankind is too dependent on honeybees.

The scientific warning signs came in two reports last October.

First, the National Academy of Sciences said pollinators, especially America’s honeybee, were under threat of collapse because of a variety of factors. Captive colonies in the United States shrank from 5.9 million in 1947 to 2.4 million in 2005.

Then, scientists finished mapping the honeybee genome. It was discovered the insect did not have the normal complement of genes that take poisons out of their systems or many immune-disease-fighting genes.

A fruit fly or a mosquito has twice the number of genes to fight toxins, according to University of Illinois entomologist May Berenbaum.

What the genome mapping revealed was “that honeybees may be peculiarly vulnerable to disease and toxins,” Berenbaum said.

University of Montana bee expert Jerry Bromenshenk has surveyed more than 500 beekeepers and found that 38 percent of them had losses of 75 percent or more. A few weeks back, Bromenshenk was visiting California beekeepers and saw a hive that was thriving.

Two days later, it had completely collapsed.

Yet Bromenshenk said, “I’m not ready to panic yet.” He said he does not think a food crisis is looming.

While many experts think this is a new type of die-off, it may have happened before.

Bromenshenk said cited die-offs in the 1960s and 1970s that sound somewhat the same. There were reports of something like this in the United States in spots in 2004, Pettis said. And Germany had something similar in 2004, said Peter Neumann, co-chairman of a 17-country European research group studying the problem.

“The problem is that everyone wants a simple answer,” Pettis said. “And it may not be a simple answer.”

Unlike the great bee die-offs of the past, when mites or other deadly pathogens left mounds of bee corpses lying by the hives, in the newest crisis there are as yet no bee bodies to forensically explore.

The bees are simply flying off by the billions as though into the void.

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