More than a quarter of honey bee colonies in the US were obliterated over the winter making a total of nearly half of all colonies disappearing in the year to April 2016.
Preliminary figures from the US Dept of Agriculture (USDA) and the Bee Informed Partnership indicate that 44% of bee colonies were wiped out during the year.
Beekeepers reported that the winter loss rate of bee colonies have reached up to 28%, an increase of 5% over the previous winter, while summer loss rate also hit 28% from 25% last summer.
These losses are considered too high to be sustainable for U.S. agriculture and the beekeeping industry.
Driving the calamity are lethal infestations of the varroa mite parasite which weakens and eventually kills colonies and the conversion of pollen-rich fields into farms producing corn and soy beans as well as the heavy use of pesticides.
Bees are crucial pollinators. Moreover, pollination is responsible for $15bn in US agriculture; the USDA claims honey bees are “a critical link in US agricultural production”.
“One in three bites of food we eat is directly or indirectly pollinated by bees. If we want to produce apples, cucumbers, almonds, blueberries and lots of other types of food, we need a functioning pollination system,” said Dennis vanEngelsdorp, a University of Maryland bee scientist.
Until recently it was believed that colony losses occurred only during winter, but now scientists are increasingly concerned that the declines are starting to take place in summer too when bees should be flourishing.
“This suggests there is something more going on – bees may be the canary in the coalmine of bigger environmental problems,” vanEngelsdorp said.
From an estimated 5 million colonies in the US in 1940, only half remain. Rescue operations, such as artificially replacing queen bees, over the last decade have managed to bring the number up to some extent.
Initial indications are that neonicotinoids, the world’s most widely used class of insecticides, pose a risk to honeybees, according to Environmental Protection Agency investigations.
Environmental groups have called for this and other pesticides to be phased out to help bee populations recover.
