I can't speak for the rest of Europe, but this is something that our newspapers etc have talked about for a few years now. At times it seams climate change is the to blame for everything,that isn't understood.
In the springs of 2012 & 13 found dozens of dead and dying bees, under a goat willow salix capra some thing had eaten their abdomens, leaving only the head and thorax, in some case's they continued crawling around like this for ages. I tried to find out what had caused it, but no one seamed to know, personally I think the bees became chilled and fell to the floor to be eaten by shrews or possibly voles if they ever take insects. This year I didn't find any, possibly the wet winter killed the predators or maybe they died out, who knows?