Humans have been associated with honeybees for thousands of years, although the first historical record of bee mortality was not until 950 AD in Ireland. Historical records throughout the Middle Ages repeatedly refer to large-scale colony losses and by the end of the seventeenth century, scientists in Europe were beginning to analyze the reasons for the repeated incidents of mass bee mortality. The most frequently identified issue was adverse weather conditions. However, factors such as pathogens or parasites may have played a role, too.
The earliest recorded shipment of the Western (or European) honeybee (Apis mellifera) to the Americas was in 1621 and ever since, bee mortality events in North America have been the subject of both observation and scientific research – right up to the present day when Colony Collapse Disorder (CCD) first came to light in the United States in 2006. There have been substantial losses of honeybee colonies in certain regions of Europe and North America during or directly after the winter months, through which the overwintering honeybees cluster together in their hive and cannot forage outside. This is possibly due to intensification of beekeeping practices in the United States, the spread of the parasitic Varroa destructor mite and the deadly viruses it transmits.
Overall, the number of managed honeybee colonies has remained either relatively stable or shown positive increases over the last ten years across North America. In Europe, colony numbers are relatively stable at approx. 15-16 million hives. Interestingly, the overall number of managed honeybee colonies worldwide has increased by some 65% over the last 50 years.
In addition to honeybees, there are more than 20,000 other bee species worldwide, including solitary bees and bumblebees, which also contribute to pollination of our crops and flowers. Some species are in decline, mainly due to changing land use and a reduction of the habitat that they rely on for food, shelter and nesting. For many solitary bees, there are few historical records of their abundance and range in the past so it is difficult to determine whether present day numbers are in decline or not.
One thing is clear, however. Bees, together with most pollinating insects, are subject to numerous pressures in much of the modern world. The need to produce more food for human consumption has led to more intensive agriculture, and this has undoubtedly contributed to the reduced abundance and diversity of flowers. The impact of weather, parasites and diseases, a lack of suitable nesting sites, agricultural and apicultural practices, and exposure to environmental chemicals have also been implicated in poor pollinator health.