Bumblebee Mimic Hoverfly - Sericomyia superbiens
What you see in the first photo is not a bee, but an extraordinary bee-mimic hoverfly scientifically named Sericomyia superbiens (Diptera - Syrphidae). This hoverfly found in most Europe, mimics the Common Carder Bee, Bombus pascuorum, a species of bumblebee with which it shares habitat
In the bottom photo you can see a comparison between the Carder Bee, Bombus pascuorum (left) and the bee-mimic hoverfly Sericomyia superbiens (right).
Many hoverflies resemble bees or wasps, not only in their shape and coloring, but also in their behavior. Some are extremely good mimics and even experienced recorders need to look twice. Explanation for this resemblance is Batesian mimicry, which in simply words means that by looking like a stinging and distasteful bee or wasp, a hoverfly gains a degree of protection from predator, even though it is actually perfectly edible.
Reference: [1]
Photo credits: ©S. Rae (CC BY 2.0) | Locality: Humbie, East Lothian, Scotland (2009-2011) | [Top] - [Bottom]