The total number of honey bee colonies across Europe plunged 16% over the winter 2017–18, according to COLOSS (Prevention of honey bee COlony LOSSes), an international, non-profit organization based in Switzerland, tasked with the goals of protecting honey bees.
Allison Gray, the lead researcher on the study, sent a COLOSS questionnaire to 25,363 beekeepers in 36 countries: 33 in Europe, plus Algeria, Israel, and Mexico.
The data collected revealed an overall loss rate of 16.4% of honey bee colonies during winter 2017/18 between the countries.
Beekeepers were asked several questions about their hives: (a) were alive but had unsolvable queen problems (e.g., a missing queen, laying workers, or a drone-egg laying queen), (b) were dead or reduced to a few hundred bees and (c) were lost through natural disaster (from various possible causes).
Gray and her team determined that Portugal, Northern Ireland, Italy, and England had the most significant colony collapses of more than 25%. The authors noted that smaller bee farms experienced higher loss rates than large-scale ones.
"The overall loss rate in winter 2017/18 was highest in Portugal (32.8%), a new country to the survey. Other countries with high losses (above 25%) were Slovenia, Northern Ireland, England, Wales, Italy, and Spain, countries mostly in Western Europe," wrote Gray.
A year earlier, loss rates were the lowest in Norway, Northern Ireland, and Algeria, and the year before that in Central Europe.
Winter losses linked to queen difficulties was 1% in Bulgaria to 20.3% in Slovenia, whereas for winter 2016/17, the rate for this loss for Slovenia was the lowest for the study.
Each hive's queen is crucial for the survival of the overall colony. If a queen goes missing or doesn't lay eggs to create more drones, the colony will collapse. Honey bees are also at risk from parasitic mites.
If honey bees don't have enough forage or food supply consists of nectar and pollen from blooming plants within flight range of the hive, the colony will collapse.
Gray found that intensive foraging on specific plant sources, including orchards, oilseed rape, maize, heather, and autumn forage crops, was associated with hive collapses during the winter periods.
The colony collapse of honey bees is a complex issue, wrote Gray, and are frequently caused by volatile weather or natural disasters rather than climate. And there is no solution at the moment.
She noted that future investigations should be conducted into the impact of pesticides, and herbicides on honey bees.
Not too long ago, we reported that honey bees exposed to glyphosate, the active ingredient in Roundup, lose critical bacterial in their guts and are more susceptible to infection and death from harmful bacteria. It showed how glyphosate is possibly contributing to a rapid decline of honey bees around the world, otherwise known as Colony Collapse Disorder (CCD), a phenomenon that occurs when the majority of worker bees in a colony disappear and leave behind the queen.
Globally, honey bees are the world's most important pollinator of food crops. It's estimated that 33% of the food people eat from around the globe rely on pollination by bees. So when the bee populations across Europe, the Americas, and other parts of the world are in decline, it could trigger lower crop yields, therefore causing food shortages and economic stress for governments and central banks.