Meta-analysis of Honeybee Colony Collapse Highlights Shortcomings

Socioeconomic and political pressures on honey production over the past few decades has caused a long-term reduction in the number of productive honeybee colonies in the US, Europe and other countries, a study by EcoHealth Alliance concluded. The research showed the more recent, increasing "annual colony losses" reported by honeybee managers to be the result of pests, pathogen and management issues, which are under researched and poorly understood.

Honeybees provide ecosystem services through pollination of crops worth $215 billion annually worldwide. Concern over the long term decline of the profitable insects has sparked debate over colony collapse disorder (CCD) and its causes.

EcoHealth Alliance, a nonprofit organization that focuses on local conservation and global health issues, conducted an in-depth, critical review of the scientific research surrounding colony declines and losses. Their findings have shown that: the declines reflect a reduction in the profitability of bee keeping due to economic and/or political change, with many bee keepers leaving the profession; data is sparse and collected in a non-uniform way that makes comparison across years difficult; there are inconsistencies with definition of CCD, suggesting that it may be over-reported; and the major causes of annual losses include pests, pathogens carried by the pests and poor management of scaled up honey bee operations.

"There is a growing understanding of the role that introduced pests and pathogens play in species declines," said Peter Daszak, disease ecologist and president of EcoHealth Alliance, in a press release announcing the research. "We call this phenomenon 'Pathogen Pollution', and bees are no exception - the role of introduced mites and the pathogens they carry is under researched and desperately in need of more work."

One factor hindering the full understanding of bee colony declines is the methodology of counting colonies. For example, in the 1980s, the USDA National Agricultural Statistics Service (NASS) "reduced" the number of colonies in the US by one million, simply by changing how colonies were counted. The NASS negated to count colonies in operation that had five or fewer hives.

"Because of the nature of colony losses, it is very difficult to collect key information on the cause unless standardized, in-depth data collection is occurring well before the loss takes place." said Kristine Smith, wildlife veterinarian and associate director of health and policy at EcoHealth Alliance. "Confusion also exists around the term Colony Collapse Disorder since the media and general public often generalize by applying this term to any larger than normal annual losses."

While conducting further research and data standardization, two important aspects remain open for more exploration: the toll of agricultural intensification on the semi-free ranging honeybee and the burden of viruses spread through Varroa mites, according to the study.