Global bee populations have, indeed, struggled in recent years, but although researchers point to a number of possible causes, neonicotinoids are perhaps the least likely culprit. The bee protection organization COLOSS (Prevention of honey bee COlony LOSSes) compared surveys of honey bee losses in 2009 and 2010 in Europe with the rates of neonicotinoid application in the same geographical areas (in a separate survey). They found no correlation.
The main suspects for causing bee deaths are viruses and other pests acting in tandem, especially the aptly named Varroa destructor mite. These parasites attach to honeybees and appear to be “both a disseminator and activator of a number of bee viruses,” according to a report on honeybee disease in Europe by the Food and Environment Research Agency. In countries experiencing bee decline, Varroa is a feared and growing presence among beekeepers – even if neonicotinoids are absent. For example, in upland areas of Switzerland where neonicotinoids are not used, bee colony populations are under significant pressure from the mites; and in France, declines in the bee population in mountainous areas are similar to those on agricultural land (although neonicotinoids are commonly used in the latter but not in the former).
Conversely, where Varroa mites are not present, bee populations thrive even when neonicotinoids are heavily used. For example, Australia, which is currently Varroa-free, boasts a thriving bee population in spite of widespread use of neonicotinoids. In fact, their bees are so healthy that Australian beekeepers export queen bees and nucleus hives to countries with declining populations. (Emphasis added)