The honeybee decline
One of the principal reasons for the decline in managed honeybee colonies, and of beekeepers, is extensive and unpredictable colony death. Moderate and predictable losses can be accommodated and planned for. However, extensive and uncontrollable losses make beekeeping as a profession, with heavy investment in material and equipment, an enterprise at permanent risk of bankruptcy. It is these colony losses that the BEE DOC aims to address.
The most recent event of colony losses is the well publicised "Colony Collapse Disorder" (CCD) that devastated the honeybee industry across the USA in 2006 and 2007 and the "Rhine valley bee poisoning" case of 2008. Whereas the causes of the colony deaths became rapidly clear for the Rhine valley poisoning and similar cases in France and Italy and appropriate actions could be taken to prevent future accidents, the causes of CCD are still ambiguous or inconclusive.
Typically, the apiculturist identifies symptoms at the colony level, and then starts diagnostic procedures to identify the disease and initiate a treatment. Yet, when clinical symptoms appear at the colony level, diagnosis often comes too late to save or cure the colony. Consequently, there is a clear need for fast, reliable, sensitive and cheap diagnostic tools that alert the beekeeper to potential problems before colony level symptoms appear.
Treatments typically rely on chemicals, which are administered into the colony to target pathogens before colony collapse is inescapable. The development of such treatments is based on searching for chemicals that are toxic to the pathogen, but harmless to the honeybee. However, so far, any chemical treatment of a honeybee disease, even if successful at the colony level in the short term, has not eradicated diseases at the population level, particularly if the pathogen has a high transmission rate and a high infectivity. As illustrated by present apicultural reality, any chemotherapy of honeybee colonies immediately leads to an obligate contamination of honey and, ultimately more worrying, to resistant pathogens. Moreover, the dramatic colony losses of the past decade suggest that treatments aiming at a single pathogen only, may in principle fall short in curing colonies altogether if the interactions between various pathogens are the main drivers of colony death.
The parasite-virus-pesticide meltdown
The most thorough search for a pathogenic cause of extensive, unexplained colony losses is the case of CCD. Despite the enormous research efforts invested in the USA, no single agent or factor emerged as the definitive cause of the phenomenon. Instead, the best hypothesis to emerge from the data is that particular virulent combinations of parasites and pathogens, rather than a classical monocausal disease, is the most likely explanation. Moreover, chronic exposures to pesticides that cause no problems for healthy colonies are suspected to interact with pathogens to produce lethal consequences for colonies already weakened by disease.
The classic example of such interactions among pathogens is the case of the ectoparasite Varroa destructor, whose lethal effect on colonies is in large part due to its ability to activate and transmit a number of viral diseases. The combination of pests, parasites and pesticides results in an inadvertent "meltdown" with one negative factor enhancing the negative impacts on honeybee health of the others.
The BEE DOC will therefore focus on the interactions of these parasites with closely associated viruses and selected pesticides. However, in the search for unknown factors and interactions detrimental to bee health, it is also essential to include a comprehensive component involving as many factors as possible. The BEE DOC will therefore take a dual-track approach to studying interactions. On the experimental side the BEE DOC will concentrate on selected model systems that maximise our chance for identifying principle interactions with the greatest significance for colony health throughout Europe, and the world.