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Entomology

Empty beehives

Mysterious syndrome wipes out bees in Europe and North America

“The price of  honey is going to skyrocket in the coming years,”  says salesperson Raquel, as she offers the product at a street fair in the city of Campinas, in the State of São Paulo. The topic being discussed at her stall was the TV program broadcast a few days earlier, warning of the disappearance in different parts of the world of the Apis mellifera bees, the species that produces honey for commercial purposes. Initially detected in Europe in 2006, the problem has already spread throughout the United States, to 30 of the 50 states, a number high enough to be considered  an epidemic. This phenomenon is beginning to be found –  albeit on a smaller scale –  in Brazil’s honey producing areas.

“The  death of  bees in large numbers is nothing new and happens periodically,”   says Constantino Zara Filho, president of the São Paulo Association of European Honeybee Apiarists (Apacame). But the mortality seen in the last few months in the United States and in Europe is important because of the number of empty beehives: more than 80% of the beehives owned by a number of beekeepers were completely empty because of the bees’  sudden death.

In Brazil, bee pathology specialist David de  Jong, from the Department of Genetics of the University of  São Paulo campus in Ribeirão Preto (FMRP-USP), has begun to investigate the symptoms of this disturbance in the collapse of the beehives (CCD, in English) and has found that bee diseases, with some of the symptoms of CCD, have worsened in Brazil. However, the impact so far has not been as serious, because, he says, “our bees are hardier and more resistant.”

Specialists are intrigued by some of the characteristics of this syndrome. One of them is that the bees simply disappear without leaving any traces – no dead bodies are found at the entrance to the beehive, which is the case in other bee diseases. Another characteristic is that, at first, the syndrome eliminates only the bees  looking for pollen and nectar. “Initially, we find the queen bee, very few adult bees and many offspring (larvae and pupae), but when there are no adult bees to gather food and take care of the young, the beehive dwindles very quickly and dies,”  explains De Jong.

Precious insects
The sudden collaapse of beehives is not only a problem for those who enjoy honey and propolis. Bees are essential for pollinating several kinds of plant species. This is why a sharp decline in the bee population can give rise to serious ecological and economic consequences. In the United States, the crops that depend on pollination by bees are an estimated US$ 14 billion industry – almond crops in California mobilize 1.4 million beehives, rented by  farmers during the blossoming period. According to De Jong, until a few years ago, the monthly rent of each beehive was about US$ 40. Now it ranges from US$ 150 to US$ 200. “And there is a scarcity of  beehives,”  he adds. This is why U.S. apiarists have resorted to importing thousands of Australian bees every year.

Several reasons are suspected for the cause of bee mortality. One of them, which is yet to be supported by scientific data, is radiation from mobile telephones  and the pollen from transgenic crops. A recent joint effort of researchers has led to more plausible causes, both in the US and in Brazil. One of these causes ? the protozoan nosema ceranae ? has recently arrived in the Americas. This protozoan was discovered in Asian bees. According to De Jong, the protozoan is common in Brazil, in the US and in parts of Europe. Another species of the same protozoan – nosema apis – attacks the bees’ digestive system. Honeybee producers have known about this protozoan for a long time. “This deadly parasite has always existed in Brazil,”  says Zara Filho. “But it is not necessary to medicate the bees because Brazil’s African bees are highly resistant to infections from this micro organism.”  The bees on this side of the Atlantic do not have any defenses against the Asian protozoan and this is why, even if they don’t die, they become more susceptible to other infections, especially those caused by viruses.

The acarus varroa destructor is another agent identified in empty beehives. It attacks up to 10% of Brazil’s African bees. Under normal circumstances, the bees used in Brazilian apiculture, which are a mixture of one European sub species and one African sub species, are resistant to this acarus. De Jong says that although most of Brazil’s beehives are infected by this parasite, there is no need to medicate the bees. Susceptibility to diseases has a strong hereditary component and when resorting to medication, the apiarist might protect bees that are susceptible to these problems. “Nature is much better at selecting resistance to diseases than we are, because it safeguards the genetic variety and only eliminates the weak specimens,”  he points out. In this case, if the apiarist wants to lend nature a helping hand, then De Jong suggests that the queen bee in sick beehives be replaced. As the queen bee is the mother of the entire beehive, a new queen bee will bring a set of different genetic features to the beehive, and this can help eliminate the genes responsible for susceptibility to diseases.

However, it seems that  parasites are not the only cause of the bees’ elimination. Consumption of toxic pollen grains, such as barbatimão, and viral infections are partly to blame. De Jong has been investigating all of these aspects in collaboration with Dejair Message, from the Federal University of  Viçosa, in the state of  Minas Gerais; their research project focuses on viral diseases in bees. The pair have also found that this still unexplained syndrome affects not only the Apis mellifera, but also native social bees, known as meliponas, or stingless bees.

The symptoms of the dying bees, however, have led De Jong to suspect that new kinds of insecticides in farming (fipronil, sold in Brazil under the Regent brand, and imidachloprid, sold under the Gaucho brand) are the beehives’  worst enemies. Both are highly toxic to bees, which is why France banned fipronil.

National syndrome
Unexpected death occurred in the Nogueira Neto melipona bee farm located in São Simão,  in the state of São Paulo. This death was observed during a project coordinated by Vera Lúcia Imperatriz Fonseca, from the University of São Paulo (USP), who is investigating the role of native bees in pollination. De Jong examined the dead beehives and bees and found no signs of the diseases. “The symptoms of the bees that I observed as they were dying were similar to those resulting from insecticide-caused death: the bees were trying to fly, turning around in circles,”  he reports. He says that at least four species of native bees were affected, in addition to African honeybees from a nearby farm. “No disease affects so many species at the same time,”  states the geneticist from USP.  Zara Filho, of Apacame, ascribes the increase in the effect of insecticides on bees to the expansion of sugar cane crops. “Pesticide is sprayed from airplanes and spreads throughout a very wide region.”

The complaints in Brazil are not that many, but are becoming more frequent. Apacame registered mortality rates in several places in the state of São Paulo that are quite far from each other. According to De Jong, reports about empty beehives similar to the collapse of the bee farms have so far been limited to apiary-intensive regions, which spread from the state of  Minas Gerais down to the state of Rio Grande do Sul. “I was recently in the Northeast, and it seems that there are no problems of this sort in that area,”  says the researcher.

So far, the collapse of the beehives is a puzzle whose pieces do not all seem to fit together. Although there are similarities in the symptoms found in Brazil, in the United States and in Europe, experts are still unable to ascertain whether it is the same syndrome. In the opinion of  Fábia Mello, from the Empresa Brasileira de Pesquisa Agropecuária Meio-Norte/Embrapa Meio-Norte ( crop and animal husbandry research center), rumors of the disappearance of bees in the states of  Rio de Janeiro, Minas Gerais and in the south of the country, might simply reflect alarm at the news from other countries. “It is important that these rumors be immediately denied, because they alarm the apiarists and ultimately jeopardize the marketing of the product. However, if beehives in Brazil do start dying out, then it will be necessary to announce this news officially to apiarists and researchers,”  says Fábia. “We are keeping a close watch on the situation in the United States. The Americans are also interested in following what’s going on here to understand what is going on there,”  says De Jong. De Jong recently attended meetings with experts in the United States, but he is far from reaching a final conclusion.

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