Recent research publications into this phenomenon have identified three poosible causes:
1 The varroa mite, a bee parasite, is now known to be the carrier of a virus which can decimate a beehive. The mite and virus are known throughout the world.
2 The neonicotinoid insecticides (used widely in agriculture but rarely in the garden) are now known to be very persistent at extremely low levels in the enviroment. Calculations indicate that at these levels these residues are not toxic to bees however they may be toxic to other invertebrates.
Bees exposed to these insecticides loose their ability to navigate and fail to locate their home hive. This research work has at the moment only been carried out on single bees.
3.Habitat loss. A study from 1934 to 2013 clearly shows the dramatic loss of the bee`s feeding habitats and the corresponding increase in agricultutral monoculture. (Habitat loss is already being partly blamed for the decline of butterfly and moth numbers).
