February 6, 2014
Uncovering The Drivers Of Colony Collapse In Honey Bees
April Flowers for redOrbit.com - Your Universe Online
A new study from EcoHealth Alliance investigated the causes of long-term honey bee colony numbers and annual colony losses, revealing that socioeconomic and political pressures on honey production over the past few decades have caused a long-term reduction in the number of colonies in production in the USA, Europe and many other countries.
The study, published in the journal EcoHealth, also reports that pests, pathogens and management issues likely play a major role in the recent losses in stocks -- or annual colony losses -- reported by honey bee managers. These driving factors are under-researched and poorly understood, according to the researchers.
Honey bees pollinate crops worth approximately $215 billion annually, worldwide. Managers and scientists have been concerned over honey bee declines in the recent decades, as well as the annual losses. This concern has sparked debate about the causes, leading to the hypothesis that a new syndrome, "Colony Collapse Disorder" (CCD), is the root problem, while other scientists have proposed factors such as pollution from pesticides as the cause of the declines.
The EcoHealth research team conducted an in-depth, critical review of the science behind the declines and losses. Their findings include:
* The downward trend in the number of bee colonies in many countries over the past few decades reflects a decrease in the profitability of bee keeping due to economic and/or political change. These forces have led many bee keepers to leave the profession.
* The collection of data on annual losses is sparse and non-uniform, making it difficult to compare the extent and potential cause of losses in the previous years.
* The way researchers and bee keepers define CCD has significant inconsistencies, suggesting that it might be over-reported.
* That the major causes of annual losses include pests—such as the Varroa mite, pathogens – viruses that these mites carry, and the need for research and advancements in management techniques available for large-scale apiaries which have evolved from smaller "back-yard" productions.
"There is a growing understanding of the role that introduced pests and pathogens play in species declines," said Dr. Peter Daszak, Disease Ecologist and President of EcoHealth Alliance.
"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," he added.
Long term declines have been documented in the Europe and the US; yet, since 1961, the overall number of global colonies has increased by 45 percent. In conjunction with the 300 percent rise in pollinator-dependent crops, the increase of colonies requires the industry to manage honey bees like never before; millions of honey bees are moved across the country annually to pollinate crops.
The methodology used to count colonies is one factor that is vital to understanding the metrics of long-term colony declines. For example, the USDA National Agricultural Statistics Service (NASS) reduced the number of colonies in the US in the 1980s by one million by changing the formulation of how colonies were counted previously. However, NASS did not count colonies in operation that had five or fewer hives. In addition to socioeconomic and political factors, the change contributed to the decrease in colony numbers over previous decades.
"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. Bee management specialists and veterinarians need to support bee keepers with information, tools, and resources to adapt to a swiftly growing production system," said Dr. Kristine Smith, Wildlife Veterinarian and Associate Director of Health and Policy at EcoHealth Alliance. Dr. Smith continued, "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."
Factors that contribute to such losses should include:
* The presence of pathogens and pests in the colony during the previous year.
* Disturbances of an environmental and ecological nature.
* Application and misuse of pesticides around the colony
* Industry and management practices such as migration, nutrition, and medical treatments
EcoHealth recommends standardization of data collection, increased surveillance and surveys of management practices. They also say that more research is needed to understand the toll of agricultural intensification on this semi-free ranging managed species and the confounding pressure of viruses spread through Varroa mites and the burden of these viruses and mites at the individual bee and colony level.