The number of wild honeybees in the US declined substantially from 1971 through 2006. Honeybees, in the wild, are now almost extinct in the U.S.. This is paralleled by a significant, more gradual decline in the number of colonies maintained by beekeepers. This has profound implications for our food supply, and the food supply of nature and all animals, including man, are directly or indirectly dependent upon the ability of plants to produce fruits and seeds.
The decline of some domestic hives can be attributed to a variety of factors such as urbanization, pesticide use, tracheal and Varroa mites, and commercial beekeepers retiring and going out of business. However, late in 2006 and in early 2007 the rate of attrition reached new levels, and the term "Colony Collapse Disorder" was used to describe this sudden rash of disappearances.
The disorder seems to mostly affect colonies that have undergone stress, such as transporting them around the U.S. for pollination jobs, but some beekeepers report that it happens even if the hives aren't transported.
Sporadic hive disappearances resembling CCD have been documented as early as 1896, and this set of symptoms has in the past several decades been given many different names (disappearing disease, spring dwindle, May disease, autumn collapse, and fall dwindle disease). Most recently, a similar phenomenon in the winter of 2004/2005 occurred, and was attributed to Varroa mites (the "Vampire Mite" scare), though this was never ultimately confirmed. Nobody has been able to determine the cause of any past appearances of this syndrome. Upon recognition that the syndrome does not seem to be seasonally-restricted, and that it may not be a "disease" in the standard sense - that there may not be a specific causative agent - the syndrome was renamed.
A colony which has collapsed from CCD is generally characterized by all of these conditions occurring simultaneously:
In the U.S., at least 24 different states as well as portions of Canada have
reported at least one case of CCD. However, in many cases, beekeepers reporting
significant losses of bees did not experience CCD, and a major part of the
subsequent analysis of the phenomenon hinges upon distinguishing between true
CCD losses and non-CCD losses. In a survey of 384 responding beekeepers from 13
states, reporting the number of hives containing few or no bees in spring, only
23.8% met the specified criteria for CCD (that 50% or more of their dead
colonies were found without bees and/or with very few dead bees in the hive or
apiary). In the US, despite highly variable anecdotal claims appearing in the
media, the best documentation indicates that CCD-suffering operations had a
total loss of 45% compared to the total loss of 25% of all colonies experienced
by non-CCD suffering beekeepers in 2006-2007; it is further noted that non-CCD
winter losses as high as 50% have occurred in some years and regions (e.g.,
2000-2001 in Pennsylvania), though "normal" winter losses are typically
considered to be in the range of 15-25%
There are also putative cases reported by the media from India, Brazil and
parts of Europe. Since the beginning of the 1990s, France, Belgium, Italy,
Germany, Switzerland, Spain, Greece, Slovenia and the Netherlands have been
affected by honey bee disappearances, though this is not necessarily associated
with CCD; Austria and England (where it has been dubbed the "Mary Celeste"
phenomenon, after the name of a ship whose crew disappeared in 1872) have also
reportedly been affected It is far from certain that all or any of these
reported non-US cases are indeed CCD: there has been considerable publicity, but
only rarely was the phenomenon described in sufficient detail. In Germany, for
example, where some of the first reports of CCD in Europe appeared, and where -
according to the German national association of beekeepers - 40% of the honey
bee colonies died, there has been no scientific confirmation; as of early May
2007, the German media were reporting that no confirmed CCD cases seemed to have
occurred in Germany.
The exact mechanisms of CCD are still unknown. One report indicates a strong but possibly non-causal association between the syndrome and the presence of the Israel acute paralysis virus. Other factors may also be involved, however, and several have been proposed as causative agents; malnutrition, pesticides, pathogens, immunodeficiencies, mites, fungus, genetically modified (GM) crops, beekeeping practices (such as the use of antibiotics, or long-distance transportation of beehives) and electromagnetic radiation. Whether any single factor is responsible, or a combination of factors (acting independently in different areas affected by CCD, or acting in tandem), is still unknown. It is likewise still uncertain whether CCD is a genuinely new phenomenon, as opposed to a known phenomenon that previously only had a minor impact.
At present, the primary source of information, and presumed "lead" group investigating the phenomenon, is the Colony Collapse Disorder Working Group, based primarily at Penn State University. Their preliminary report pointed out some patterns, but drew no strong conclusions. A survey of beekeepers early in 2007 indicates that most hobbyist beekeepers believed that starvation was the leading cause of death in their colonies, while commercial beekeepers overwhelmingly believed that invertebrate pests (Varroa mites, honey bee tracheal mites, and/or small hive beetles) were the leading cause of colony mortality. A scholarly review in June, 2007, similarly addressed numerous theories and possible contributing factors, but left the issue unresolved.
In July, 2007, the USDA released its "CCD Action Plan", which outlines a strategy for addressing CCD consisting of four main components:
As of late 2007, there is still no consensus of opinion, and no definitive
causes have emerged; the schedule of presentations for a planned national
symposium on CCD, titled "Colony Collapse Disorder in Honey Bees: Insight Into
Status, Potential Causes, and Preventive Measures," which is scheduled for
December 11, 2007, at the meeting of the Entomological Society of America in San
Diego, California, gives no indication of any major breakthroughs
One of the more common general hypotheses concerns pesticides (or, more specifically, insecticides), though several studies have found no common environmental factors between unrelated outbreaks studied.
Potential effects on honey bees of gathering pollen and nectar from genetically modified (GM) crops that produce Bacillus thuringiensis (Bt) toxin have been investigated, and there is scant evidence of deleterious effects on bees visiting such crops. Corn (maize), the major such crop, is not a preferred plant for honey bees, although beekeepers who keep bees near corn fields state that "corn is an excellent source of pollen when in tassel". Cotton, the second important Bt crop, is highly subject to bee visitation for nectar (pollen is only consumed if there is no other pollen available), but there is no credible evidence of toxicity of GM cotton, other than that from insecticides used during bloom.
The Sierra Club Genetic Engineering Committee recently published a letter to Senator Thomas Harkin on the web.They are of the opinion that "highly respected scientists believe that exposure to genetically engineered crops and their plant-produced pesticides merit serious consideration as either the cause or a contributory factor to the development and spread of CCD." Nine literature references which might support this theory are cited The primary effects of Bt on insects is in the larval stage. Thus the studies on Bt-toxins and effects on honey bees originally concentrated more on larvae and their development. However, as pollen is an important part of bee bread, which is also food for adult bees, some beekeepers think that adult bees may be more affected by ingredients of pollen, because adult bees are something like a filter for larvae. And as the CCD phenomenon involves the disappearance of the adult bees, some think there could be a direct connection despite the absence of symptoms in the larvae, and despite any evidence that the bees experiencing CCD have ever been exposed to GM crops.
In 2005 Bt maize, which is commercially planted in the US since 1996, accounted for 35% (106,400 kmē) of total US maize plantings. GM insect resistant Bt cotton has also been grown commercially in the US since 1996 and by 2005, was planted on 52% (28,000 kmē) of total cotton plantings. According to David Hackenberg, former president of the American Beekeeping Federation and leading the public information concerning CCD as a beekeeper, "beekeepers that have been most affected so far have been close to corn, cotton, soybeans, canola, sunflowers, apples, vine crops and pumpkins", though Hackenberg personally attributes CCD to neonicotinoid pesticides applied to these crops.
Thus, some Bt plants may have been visited by honey bees that later exhibited CCD. However, similar massive bee die-offs (or disappearances) have been recorded for decades prior to the introduction of these crops, and also "have occurred in Europe and areas of Canada where Bt crops were not grown." According to the European Union's GMO Compass Bt maize is grown in Spain, France, Czech Republic, Portugal, Germany and Slovakia. Various documents relating to US risk assessment studies on Bt in relation to honey bees are published on the United States Environmental Protection Agency (EPA) homepage for Biopesticides Registration Action Documents; there is no indication that any of these studies found effects of Bt pollen on honey bees.
A research study conducted in Germany suggested that rather than having a direct effect, exposure to Bt maize pollen may weaken the adult bees' defense against Nosema, though in the absence of such an infection, there were no detectable effects:
Bee rental for pollination is a crucial element of US agriculture, which could not produce anywhere near its current levels with native pollinators alone US beekeepers collectively earn much more from renting their bees out for pollination than they do from honey production.
Researchers are concerned that trucking colonies around the country to pollinate crops, where they intermingle with other bees from all over, helps spread viruses and mites among colonies. Additionally, such continuous movement and re-settlement is considered by some a strain and disruption for the entire hive, possibly rendering it less resistant to all sorts of systemic disorder.
One major US beekeeper reports moving his hives from Idaho to California in January, then to apple orchards in Washington in March, to North Dakota two months later, and then back to Idaho by November -- a journey of several thousand kilometres. Others move from Florida to New Hampshire or to Texas; nearly all visit California for the almond bloom in January.
Beekeepers in Europe and Asia are generally far less mobile, with bee populations moving and mingling within a smaller geographic extent (although some keepers do move longer distances, it is much less common).
This wider spread and intermingling in the US has resulted in far greater losses from Varroa mite infections in recent years.
Some beekeepers think the culprit may be climate change, in which the earth as a whole is warming but regional and local temperatures may drop much lower or rise higher than normal. "Erratic weather patterns caused by global warming could play havoc with bees' sensitive cycles. A lot of northeastern U.S. beekeepers say a late cold snap is what did the damage to them this year". Indeed an unusually dry and warm winter prevented the flowering of many plants, "If there is not a common thread, such as a pathogen seen in many of the affected colonies, Professor Eric Mussen of UC Davis said he is convinced that a nutritional deficit helps explain how the honeybees were weakened by the smorgasbord of potential causes of death. That is because dry conditions, certainly in California, did not produce flowers in which bees find their required mix of pollens, he said ... 'In many situations the bees were weakened by not being able to get a nice mix of nutrients that they needed from the pollens, and I think that weakened them,' he said. 'Under those circumstances you can take all the other (causes), and there are plenty of them, and combine them together and down go the bees'".
"Dry conditions in many parts of the country last fall reduced good nectar flow, so fewer good fall pollens were taken into colonies. 'Bees rely on fall pollens to rear a brood and take them through the winter. It was a hard fall, followed by a warm winter, and bees were out flying. There weren't any resources (food) out there, so the bees were burning up flight muscles'". "Well, you get this blast of hot temperature, which is about the time the flower buds are forming and the pollen grains are beginning to form. What does that do? You get sterile pollen. A beekeeper could look into the hive and say, "I've got all kinds of pollen in there and the bees disappeared." Well, right, you've got pollen grains, but do they have any nutrition in them? ... I think something happened at the end of last year in many places in the temperate climate around the world, not just here, and fouled up the bees' food supply. Unless somebody tells me differently, I'm blaming it on the weather ... for whatever reason, we are beginning to kind of move into a cycle where we are going to find more extremes than we used to have. The droughts may be hotter and longer, the storms and floods may be more severe. Things aren't going to be so nice in the future". In fact the first half of 2006 was the warmest on record in U.S.
Some say that flowers are blooming earlier than in the past, "Climate change and earlier springs have also taken a toll. Plants like red maples and pussy willows, typically the first pollen sources for honeybees, have been blossoming weeks before the bees can fly in the spring, Conrad [author of Natural Beekeeping] said, so they miss out on that important source of pollen" . Wayne Esaias, a NASA climatologist and beekeeper has been keeping tabs on the possible connection . See also Bees, Pollination and Climate Change: A Guide to Selected Resources.
In April 2007, news of a University of Landau study appeared in major media,
beginning with an article in The Independent that stated that the subject of the
study was mobile phones and had related them to CCD. Cellular phones were
implicated by other media reports, but were in fact not covered in the study,
and the researchers have since emphatically disavowed any connection between
their research, cell phones, and CCD, specifically indicating that the
Independent article had misinterpreted their results and created "a horror
The 2006 University of Landau pilot study was looking for non-thermal effects of radio frequency ("RF") on honey bees (Apis mellifera carnica) and suggested that when bee hives have DECT cordless phone base stations embedded in them, the close-range electromagnetic field ("EMF") may reduce the ability of bees to return to their hive; they also noticed a slight reduction in honeycomb weight in treated colonies. In the course of their study, one half of their colonies broke down, including some of their controls which did not have DECT base stations embedded in them.
The team's 2004 exploratory study on non-thermal effects on learning did not find any change in behavior due to RF exposure from the DECT base station operating at 1880-1900 MHz.
Like the links to CCD from variants (herbicides, genetically modified crops, etc), the link of either cordless or cellular phones, cell towers, interference by HAARP (High Frequency Active Auroral Research Program) or GWEN (Ground Wave Emergency Network) to CCD is speculative..
The phenomenon is particularly important for crops such as almond growing in
California, where honey bees are the predominant pollinator and the crop value
in 2006 was US$1.5 billion. In 2000, the total U.S. crop value that was wholly
dependent on honey bee pollination was estimated to exceed US$15 billion.
Honey bees are not native to the Americas, therefore their necessity as pollinators in the US is limited to strictly agricultural/ornamental uses, as no native plants require honey bee pollination, except where concentrated in monoculture situations-where the pollination need is so great at bloom time that pollinators must be concentrated beyond the capacity of native bees (with current technology).
They are responsible for pollination of approximately one third of the United States' crop species, including such species as: almonds, peaches, soybeans, apples, pears, cherries, raspberries, blackberries, cranberries, watermelons, cantaloupes, cucumbers and strawberries. Many but not all of these plants can be (and often are) pollinated by other insects in small holdings in the U.S., including other kinds of bees, but typically not on a commercial scale. While some farmers of a few kinds of native crops do bring in honey bees to help pollinate, none specifically need them, and when honey bees are absent from a region, there is a presumption that native pollinators may reclaim the niche, typically being better adapted to serve those plants (assuming that the plants normally occur in that specific area).
However, even though on a per-individual basis, many other species are actually more efficient at pollinating, on the 30% of crop types where honey bees are used, most native pollinators cannot be mass-utilized as easily or as effectively as honey bees-in many instances they will not visit the plants at all. Beehives can be moved from crop to crop as needed, and the bees will visit many plants in large numbers, compensating via sheer numbers for what they lack in efficiency. The commercial viability of these crops is therefore strongly tied to the beekeeping industry.
The following tentative recommendations have been proposed for beekeepers noticing the symptoms of CCD