Studies fault Bayer in bee die-off

A corn pesticide manufactured by the German chemical company Bayer has come under scrutiny in two scientific studies that indicate that it is responsible for mass deaths of pollinating bees.

Honey Bee

Source: Studies fault Bayer in bee die-off, by Josephine Marcott, Minneapolis Star Tribune

Colony collapse disorder

Colony collapse disorder (CCD) is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of disappearances of Western honey bee colonies in North America in late 2006. Colony collapse is significant because many agricultural crops worldwide are pollinated by bees.

European beekeepers observed similar phenomena in Belgium, France, the Netherlands, Greece, Italy, Portugal, and Spain, and initial reports have also come in from Switzerland and Germany, albeit to a lesser degree while the Northern Ireland Assembly received reports of a decline greater than 50%. Possible cases of CCD have also been reported in Taiwan since April 2007.

Multiple possible causes of CCD have been identified. In 2007, some authorities attributed the problem to biotic factors such as Varroa mites and insect diseases (i.e., pathogens including Nosema apis and Israel acute paralysis virus). Other proposed causes include environmental change-related stresses, malnutrition, pesticides (e.g.. neonicotinoids such as clothianidin and imidacloprid), and migratory beekeeping. More speculative possibilities have included both cell phone radiation and genetically modified (GM) crops with pest control characteristics. Relatively little attention has been given to the artificial selective breeding of bees for industrial use, the displacement of and stressors on wild bees, and the effect of artificial genetic homogeneity on increased predisposition and uniform susceptibility to disease.

It has also been suggested that it may be due to a combination of many factors and that no single factor is the cause. The most recent report (USDA - 2010) states that “based on an initial analysis of collected bee samples (CCD- and non-CCD affected), reports have noted the high number of viruses and other pathogens, pesticides, and parasites present in CCD colonies, and lower levels in non-CCD colonies. This work suggests that a combination of environmental stressors may set off a cascade of events and contribute to a colony where weakened worker bees are more susceptible to pests and pathogens.” Applying proteomics-based pathogen screening tools in 2010, researchers announced they had identified a co-infection of invertebrate iridescent virus type 6 (IIV-6) and the fungus Nosema ceranae in all CCD colonies sampled. However, subsequent studies have questioned the methodology used in these proteomic experiments.

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