Scientists are sounding the alarm.
Bees and other pollinating insects have their number dropped alarmingly, putting their future survival at risk, and could have dramatic consequences for ecosystems and agriculture.
More and more scientific studies suggest that changes in farming practices could make bee populations vulnerable to pests and parasites, dangerously increasing mortality rates. Changes in pesticide use could even be responsible for the collapse of entire bee colonies.
Effects of pesticides on honeybee hives
INRA (National Agronomic Research Institute) researchers have recently shown that it is the combination of an infectious agent and an insecticide that threatens hives. A deadly cocktail that should require a review of the procedure for the evaluation of pesticides.
The imidacloprid, the active agent of the Gaucho, a systemic insecticide, and Nosema Ceranae and a microparasite of the bowel weaken together bees or kill them massively.
This was shown by Cédric Alaux, Yves Leconte and their colleagues at INRA Avignon, in a previous study curiously unnoticed: “Our study shows that if they are contaminated with Nosema, bees exposed to Imidacloprid even in minute quantities, succumb to Nosema” said Yve Leconte.
A result that may shed a new light on the decline and mass mortalities observed in bee colonies in the United States, France, and in most European countries. For today, according to the ANSES (the French Agency for Food, Environmental and Occupational Health Safety) Imidacloprid residues are found in 50% of France’s hives. And the presence of Nosema Ceranae has proven in almost all of them since at least 2002, as shown by Marie-Pierre Chauzat – from the ANSES.
But until then, as the pesticide industry continues to proclaim, the insecticide alone is not considered lethal at low doses. No more than also Nosema – Marc-Edouard Colin, of Supagro (Montpellier) has already shown in 2006 that Nosema was present in hives that worked perfectly normally.
However, the combination of the two is a time bomb.
Bee disappearances are not a new phenomenon. They have been regularly observed and described since 1896. But a more important and widespread phenomenon seems to affect domesticated honeybees since the late 1990s (the other species are poorly studied and even less monitored!)
It has been observed over the last seven years inexplicably high mortality rate among bee populations, a phenomenon called " Colony Collapse Disorder " or CCD. Apparently healthy colonies suddenly collapsed, leaving the brood (larvae) and food stocks, and sometimes leaving only the queen in the hive.
This syndrome is believed to be serious by beekeepers themselves of course, but also by many economists and more and more scientists, because of the ecological and economic importance of bees.
The bee is usually considered a telling "sentinel" of the state of the environment, due to its presence almost everywhere on earth, its ability to collect, via pollen and nectar, minute doses of pollutants and of course because they are closely observed by beekeepers themselves whose survival depends on the health of hives.
The precise causes of the colony collapse disorders of bee colonies have not yet been formally identified. A number of factors are thought to contribute to this decline, including the emergence of new viruses and climate change. But there are clear indications that modern agricultural practices, particularly the prevalence of monoculture farms and their dependence on pesticides could be a key element.
The hypothesis that the neurotoxic pesticides play a key role has a growing support among scientists and members of the community of beekeepers. Indeed, there is evidence to show a high correlation between the countries facing the largest losses of bees and those using the most pesticides. 
A previous example of high mortality among bees in France was shown to be the result of the coating of pesticides used on sunflower seeds (up to the interruption of the practice with certain pesticides). The peak of the new colony collapse disorders occurred in spring 2008 in France, Germany, Italy and Slovenia, where a high amount of neurological pesticides was present in the air, after planting treated seeds.
A report published in March 2011 by the United Nations Environment Programme, the UNEP, collects and analyzes the latest scientific data on colony collapse disorders.
The study called "Global Bee Colony Disorder and other threats to Insect Pollinators" explains the many factors suspected of decimating bee populations worldwide. 
In Europe, the artificial decline of bee colonies goes back to the mid-1960s. It has accelerated since 1998, especially in Belgium, France, Germany, Italy, the Netherlands, Spain and the United Kingdom.
In North America, since 2004, the disappearance of honeybee colonies has reached worrying levels. Population levels of these pollinators have never been lower than during the last 50 years.
Chinese beekeepers who manage western and eastern species of bees have recently noticed several unexplainable and complex signals of alteration of colonies, for both species.
A quarter of Japanese beekeepers have recently been confronted with sudden losses of their bee colonies.
In Africa, beekeepers who exercise along the Egyptian Nile also said they noticed early signs of colony collapse disorders, although to date there is no other real evidence confirmed on the rest of the African continent.
Peak demise in spring 2007
In 2007, specialists considered an alarming peak of bee demise catastrophic, threatening the pollination of many fruit and vegetable crops in the United States in particular. 
Apples, but also almonds, avocados, cherries, onions, cucumbers, cotton, peanuts, melon, etc. depend 90% or even 100% of the bees for their pollination.
Services to the pollination offered by bees are estimated at about fifteen billion dollars a year in the United States.  Some beekeepers have lost 70% of their bees in that year. 
In 2007, the rate of abandoned or almost deserted hives dropped reached 70% or even 80% in the most affected regions and countries. A quarter of the livestock of hives from the United States would have disappeared during the winter of 2006-2007 alone, and 35 States have been affected says a report from the American Congress of June 2007. 
In Europe, many countries have announced significant losses (France, Belgium, Italy, Germany, Switzerland, Spain, Greece, Portugal and the Netherlands since 2000. In the most affected hives up to 90% of bees disappeared.
Many beekeepers and scientists are concerned about the new class of insecticides called neonicotinoid systemic insecticides as the main factor behind the mass disappearance of bees in recent years.
We have already identified nearly fifty scientific studies exposing the devastating effects these neonicotinoid insecticides could have on bees.
The Task Force on System Pesticides, an independent group of 53 scientists from around the world conducted in the utmost secrecy a study on neonicotinoid pesticides - suspected of decimating bees.
Their conclusions are clear: not only are these pesticides highly toxic to bees and other pollinating insects, but they affect birds, aquatic fauna, mammals and perhaps even humans.
We invite you to browse these studies on the POLLINIS website, to get an idea for yourself about the state of knowledge on the subject.
Several scientific studies suggest that one of the causes of the disappearance of bees would be a weakening of their immune system, reflecting mainly an impoverished diet. Researchers at INRA Avignon for example, have shown in a study published in January 2010 the importance of the variety of pollen on bee health. (1)
To test the effect of the amount of protein provided by pollen and pollen diversity on the immunity and health of bees, groups of 80 bees were fed pollen from one variety of flower and other groups with six different flower pollen. The experiment was repeated on five different colonies.
The researchers found that after a few weeks the bees that had the most varied diet with a mixture of pollen, also had a rate of greater variety of a particular enzyme (called glucose oxidase). It is through this enzyme that bees make antiseptic products (natural "medicines") found in the diet of larvae and honey. These drugs are used to sterilize food for the entire bee colony, and therefore contribute to the prevention of diseases within the colony.
Bees fed with pollen from only one flower produce less antiseptic than those fed with pollen from several flowers, and therefore the colony becomes more susceptible to diseases.
And even more interesting, in the same experiment, the researchers found that the biodiversity of the pollen is more important in itself that its protein content, but which are essential to the development of young larvae. At equal protein rate, pollen from five different species feeds better the bee than a single species.
A similar study on larval feeding bumblebees (2) gave the same results. Larvae fed with several types of pollens were larger than those that were fed with a single pollen.
«The results are spectacular», say the researchers who will continue their work to identify now what mixture of pollen is optimal to develop the immunity of bees.
Restore as quickly as possible a rich natural diversity
The constitution of flowering fallows in large areas of monoculture, where only one variety of cereal, wheat or rapeseed is grown for example, is one of the widely adopted solution for a balanced diet for bees.
But it is certainly not the only one.
This is especially the enrichment of the agricultural landscape throughout France of semi-natural elements such as hedgerows, thickets or wasteland bordering fields, rich in flowers of all kinds which remains the key to this varied diet and a rich biodiversity.
For more information:
(1) The study of Cedric Alaux for the INRA Avignon «Diet effects on honeybee immunocompetence» published in Biology Letters: http://rsbl.royalsocietypublishing.org/content/early/2010/01/18/rsbl.2009.0986
(2) Study on the bumblebee «Nutritive value of 15 single pollens and pollen mixes tested on larvae produced by bumblebee workers», published in Apidologie: http://www.apidologie.org/index.php?option=com_article&access=doi&doi=10.1051/apido:2008017&Itemid=129
The question on GMOs (genetically modified organisms) remains difficult to address. The effects on human health and the environment are still poorly known and experiments are often contradictory in their conclusion. After pesticides and herbicides it would seem that GMOs are the next to be responsible for the death of bees.
Definition of a Genetically Modified Organism
It is an organism (animal, plant, bacteria) which genetic material (genetic code) was modified by a recent technique called «genetic engineering» the transgenesis to give it a new feature (eg. ability to repel insect pests or resist cold...). You select one or more genes from an existing species and you introduce them into the gene pool of the species that you want to change. Genetic transformation can be performed on many plant species, from cereals to vegetables or trees. Overall, more than 60 species can now be processed. The most advanced GMOs are mostly field crops such as corn, sugar beet and oilseed rape. The introduced genes are very diverse but for now useful characters for agriculture are favored.
Knowing that plant GMOs are not strictly «natural» species, what are the impact on their main pollinator the honeybees?
The mechanism of operation of GMOs works through protease inhibitors (PIs). Genetically modified plants proteins produce these proteins but you can also obtain them in nature in a purified state. At certain concentrations, PIs have more or less harmful effects on the digestive tract of the bee, which can block important enzymes for digestion of the insect.
A study was to introduce genes that make protease inhibitors (PIs) in certain plants visited by bees and note the effects on them according to three criteria: the behavior when foraging, learning ability (10) and the lifetime of the bee. The results of this study showed that there were no differences in bee behavior when foraging, whether foraging modified plants (introduced genes) or control plants. On learning ability, there were also no differences between bees that had foraged the modified plants and those that had foraged the control plants, with natural nectar. Finally, the life of larvae and bees depended on the concentration of PIs; naturally, their concentration did not cause more mortality than the control culture.
This study demonstrates that the risks incurred by bees facing GMOs are still very low and remain acceptable for now. GMOs are not the main cause of the colony collapse disorder of hives.
The GMO plants to which must be paid more attention regarding the bees are those that produce an insecticide and those that produce a protein conferring resistance to a herbicide.
Currently the only GM crops authorized in France are colza producing PI insecticide (protease inhibitor) and maize producing the Bt insecticide. In the first case, the insecticide is a protein, which blocks an essential enzyme in the digestion of beetles. The bee also lacks the enzyme that is likely to be blocked and therefore is irrelevant to this protein. Experiments conducted in laboratory and under tunnel conditions confirmed that ingesting this protein did not affect the bee, even in the long term. Furthermore, this protein is not present in the nectar or in the pollen. This protein is also naturally produced in rice and soybeans.
Regarding Bt maize, the introduced gene comes from the Bt bacterium, Bacillus thuringiensis and produces a protein that destroys the epithelial cells of the digestive tract of Lepidoptera (butterflies). It is used to fight against the borer. This protein is present in the pollen of maize, but is harmless to bees. This protein is also well known to beekeepers since Bt has long been used in organic farming and beekeeping under the trade name of B 401, for the treatment of frames against the wax moth.
Regarding the GMOs having a gene resisting herbicide, we must first know how the herbicide in question works.
The best known herbicide is glyphosate (Round Up). Glyphosate is a molecule which specifically recognizes a very essential enzyme of the chlorophyll absorption by blocking it, which results in the death of the plant. This herbicide acts only on the green parts of plants and therefore has no effect on bees. To make a plant resistant to this herbicide, a second copy of the gene for this enzyme is transferred to the plant, but by modifying it slightly in a region not involved in the function of the enzyme. In this way, the enzyme retains all properties, but is no longer recognized by the glyphosate and the plant can grow normally. This GMO plant has no foreign gene and is therefore equivalent to the non-transformed plant for bees and humans.
Another herbicide against which GM crops are developed is glufosinate (Basta). Glufosinate is a molecule that blocks the functioning of an enzyme for the synthesis of glutamine and is thereby causing an accumulation of ammonium, which leads to intoxication and the death of the plant. To make a plant resistant to this herbicide, no foreign gene is introduced, but another copy of the gene of the enzyme in question is added to it. There is an overproduction of the enzyme as a result and glufosinate can only block a portion of it, the non-blocked portion of the excess of the enzyme allows the plant to grow normally. As in the previous case there is no foreign protein in the plant and it is similar to the untransformed plant for the bee and humans.
However the culture of this plant involves the use of glufosinate herbicide. The human being possesses the enzyme that blocks this molecule, but it does not cause intoxication because humans have other ways of glutamine synthesis that can take over, but for the bee, this possibility has not been demonstrated to our knowledge. It is not excluded that the insecticide in question may present a danger to the bee; its toxicity has been demonstrated for a small butterfly.
The Asian hornet (Vespa Velutina) are usually found in India, China, Indonesia ... and since late 2004: in France. In 2007, 1500 nests were found in the regions of Gironde, Dordogne and much more in the Lot et Garonne.
The proliferation of the species has important implications for the European bee.
The Asian hornet attacks the bees to steal their pollen and feed their larvae.
It is said that the hornet Vespa Velutina has traveled to France aboard a cargo ship whose cargo of Chinese pottery was landed in the Lot and Garonne. The species has easily adapted to the climate and the French environment. It thrives today with even more ease because there are almost no predators for them on our soil.
Our European honeybee (Apis Mellifera) is completely helpless in front of the attacks of this insatiable killer. Unlike Asian bees (Apis Cerana) that developed during their evolution an effective method to defend themselves: they are fighting back together and form a cluster of bees around each hornet to make its body temperature rise and kill it - the bee’s body temperature is about 2° higher than the one of the hornets.
Oddly enough, European bees do not react to the attack of Asian hornets. And let the attackers systematically decimate the foragers.
For the Asian hornet attacks almost exclusively foragers in Europe. It remains in hovering at the entrance of the hive and attacks bees loaded with pollen. It takes them and beheads them with its mandibles for cutting them up a little further, the hornet makes a dumpling out of the bees which he removed the wings and legs to feed its larvae. It can kill and take two bees every three seconds.
The adult hornet yet eats ripe fruits and nectar.
The queen builds the nest during spring, which is built usually very high in the trees, 12 to 15 meters above the ground. Each nest can contain up to 2,000 hornets. It is abandoned during the winter.
The Varroa Destructor
The Varroa Destructor is a mite native to Asia that began colonizing swarms around the world from 1950. It is seen for the first time in France in 1982 and these days they are found in more than a hive in two across France.
The Varroa parasited originally the Apis Cerana, which is the common bee species in Asia and could originally only be found there. For this reason Apis Cerana tolerates the Varroa Destructor, which is living at its expense in the hive.
But with the development of international trade, the importation of bee swarms, and the crossing of species, the Varroa that had always lived with the Apis Cerana is well accustomed to our European bee whose hives he has gradually settled worldwide.
The Varroa looks like a small-flattened red crab 1 to 1.8 mm long and 1.5 wide. It has short legs that allow it to cling to a bee and its body is covered with silk.
The female Varroa mite lays eggs in the cells harboring bee larvae. Eggs fertilized by male Varroa become females while the others become infertile males. Young Varroa feed on the food of the bee larvae and adult females feed on Bes « blood » (hemolymph). Females are adult in nine days and males in 7 days. The male depends on the food given to the larvae, so it must fertilize the female before the bee gets out of the cell, he dies afterwards because of lack of food. Females live longer and follow the movements of bees clinging to the worker bees and bumblebees, so it can easily change the hive and colonize an area.
A single bee can host multiple Varroas, and we understand why the bees eventually die. At bee larvae it causes malformations of the larvae that causes long-term damage to the entire hive. If the spread of the mite is great within the same hive and is untreated the colony of bees are rapidly depopulated. Varroa mites are difficult to locate because of its small size.
Some Apis Mellifera are more resistant to the Varroa as they destroy selectively the cells of the hive or box where the Varroa mite has already produced offspring, cells containing sterile Varroa females are not destroyed. The destruction of the Varroa that had descendants is one of the mechanisms explaining the resilience of Asian bees to Varroa.
The Nosema Ceranae fungus
The Nosema Ceranae is a protozoan, a unicellular being, which attacks the epithelial cells of the gut of the bee. It is also native to Asia. We do not know the ways he borrowed to conquer Europe, but it is also well established in the French beekeeping landscape.
Apparently he only attacks colonies already weakened by poor nutrition, adverse weather conditions moving colonies from one place to another...
Nosema Ceranae is a microsporidian which, when ingested by the bee enters the epithelial cells of the intestine and reproduces by mitosis, creating spores that will in turn multiply in another cell and destroy it, and so on until it destroys almost completely the wall of the insect gut.
The cells thus destroyed cannot produce an enzyme used to catalyze the hydrolysis of food into nutrients that can then pass into the hemolymph ("blood") of the bee. The bee is therefore seen to have protein deficiency and poor digestion that result in loss of energy and dysentery (diarrhea). As a result of this energy loss, the bee eats more, drawing on reserves for other bees or brood, weakening the hive.
Contamination: Infection occurs via pollen and bee droppings, which are already infested. When bees form a ball, they stick pollen grains with honey or nectar content in their craw, which can contain spores of Nosema Ceranae (when infected). If another bee comes to consume one, Nosema Ceranae spores arrive in its intestine and the new bee is contaminated. Bee droppings are also a means of contamination because the bee contaminated having dysentery sometimes defecate in the hive. There the Nosema Ceranae spores, which are resistant to cold and hot and are provided with an envelope that protects them, can survive up to one year or more in the feces and if another bee eats them (which happens), it is also contaminated.
Contamination is also done through the dead bees in which Nosema Ceranae spores remain alive 5 to 6 weeks and can contaminate far more bees.
Winter is the best season to infest the hive: the bees defecate (they only come out rarely) and eat the reserves (some of which contain spores of Nosema Ceranae), and dead bees remain in the hive; so there is a greater chance for a healthy bee to be contaminated.
Effects on the hive:
By their decreasing number, bees are not numerous enough to take care of the brood: foragers (fewer and more tired) will bring back less food, so the brood is less well nourished and gives rise to less foragers who will bring less food, etc.
If Nosema Ceranae affects the queen, it may become sterile or lay eggs of poor quality (if the ovaries are damaged) or die too.
In this case, there are two ways:
· If the season is favorable and there is enough food to raise a queen the hive hurries to raise another queen and the colony has a reprieve;
· If the weather is not good or there is not enough food, the hive is an orphan and collapses.
Nosema Ceranae also attacks bees’ macrophages cells (in the same way as the epithelial cells of the intestine). Without intestinal wall and without immune defense, bees are more susceptible to other diseases and viruses, which without obstacle to their proliferation can « help » Nosema Ceranae to kill bees. So, bees infected with Nosema Ceranae die of weakness (away from the hive, so you might find few bodies) and of dysentery. They can also die from diseases that take advantage of their weakness in order to « kill » them, but they are also more vulnerable to the effects of pesticides, what the researcher Joe Cummins suspects, after experiments on the European corn borer (caterpillar devouring parasite corn cobs), revealed that insects infected with Nosema Ceranae are more sensitive to the effects of insecticides.
Article in preparation. Thank you for your patience.