European bees are at their best health level in years as overwintering losses of colonies sink to record low

The FINANCIAL — Monheim – European bees are much healthier than many recent media publications appear to suggest. Overwintering losses of honey bee colonies – an important indicator of general bee health – were at their lowest level in years in 2013/2014, new field data from nearly 400,000 bee colonies from 21 countries in Europe and the Mediterranean show.

“It is great to see that our bees have come out of the 2013/2014 winter in the best shape for many years,” said Dr. Christian Maus, Global Pollinator Safety Manager at Bayer CropScience. “These results are also very telling since the data relate to a season during which neonicotinoid-based crop protection products were still in common use throughout Europe. This offers further evidence that these important components in the toolbox of farmers do not impact the survival of honeybee colonies during overwintering under real-life field conditions,” Maus added.

The non-profit honey bee research association COLOSS (prevention of honey bee COlony LOSSes), which comprises more than 360 scientific professionals from 60 countries, has published new data showing that the overall mortality rate of bee colonies in the 2013/2014 winter was on average 9 percent – losses below 10 percent are considered to be normal. This compares with loss rates of up to 37 percent that were recorded from individual countries in previous years, according to Bayer AG.

Mite infestations impact overwintering

In winter, honey bees are generally not active outside the hive; they are very busy inside taking steps to ensure the colony’s survival. They continue to access stored food – honey and pollen – and generate heat within the hive to protect the colony. If adequate provisions have not been made during the summer and fall, e.g. by the beekeeper, then a colony may not survive the winter season because of starvation.

Another major factor affecting honey bee colonies in the winter is Varroa mite infestation, often linked with secondary infestations by viruses. Adult winter bees that were infested with Varroa as immature bees within the brood cells do not fully develop the physiological characteristics of a long-lived winter bee. This makes them less likely to withstand the grueling environmental stressors associated with winter conditions and survive until the spring, according to Bayer AG.

“The contributions of many factors which are correlated to colony losses seem to be very dependent on weather conditions. Colonies built their brood nests late because of the relatively cold spring in 2013. This may have decreased the number of reproductive cycles of the parasitic Varroa mite, producing fewer mites. Good weather in the summer then provided excellent foraging opportunities,” the coordinator of the COLOSS Working Group, Dr. Romée van der Zee from the Dutch Centre for Bee Research said.

Neonicotinoids do not cause harm to bee health in proper farming practice

Restrictions on neonicotinoids came into force in Europe in December 2013 as a result of the European Commission´s concerns, that this group of crop protection products, which is used to control pests that damage field crops such as maize and oilseed rape, might pose a risk to bees. However, as many scientific studies, field monitoring data and risk assessments have shown, neonicotinoids do not cause harm to bee colonies under real-life field conditions, when they are used responsibly and properly, according to label instructions.

“It seems that everyone is looking for just one culprit for reduced bee health and colony losses, but you can’t point the finger of blame at a single factor. Bees are facing multiple challenges around pests and pathogens, loss of foraging habitat and poor farming and beekeeping practices. Pollination matters to agriculture, hence safeguarding the health of bees is a shared responsibility of all the partners involved: farmers, beekeepers and industry,” said Annette Schürmann, Head of the Bayer Bee Care Center.

This is underscored by a landmark study published in May 2014 in the Proceedings of the Royal Society. A group of international scientists led by Professor Charles Godfray and Professor Angela McLean, University of Oxford, analyzed the natural science evidence base relevant to neonicotinoid insecticides and insect pollinators. They concluded that “there is poor geographical correlation between neonicotinoid use and honeybee decline”.