Please people, shake off this negative notion about BB.
They are an important link in a long chain that is Nature and they have a place in our world the same as our Honey bees do...
If any danger is present, it is danger from our bees spilling over to the BB.
Research indicates that varroa and other asociated maladies are spreading on BB and wrecking havoc with them. In many parts of the globe they are fast disappearing; In the USA about 78% of them are already gone. In UK many species are already gone and Germany last year became alarmed, cause people noticed lack of BB?!
Remember, if honey bees are/become absent/disappear, bumbles will be one of only other major pollinators left to do the job such as it is.
Besides, BB are the only suitable pollinators that will work inside the greenhouses, plus few varieties of solitary bees. BB are the only bee that will not panic in the greenhouse, or when done, will not make a beeline to the first source of light - go on the glass and there walk, up and down, until dying. . .
Bumbles work by sight and not by orientation of the sun. In other words; BB will stay at the ground and work from flower to flower, thus be able to come out where one goes in. Our bees will get in alright, but when done it flies up into the sky, thus getting caught on the glass and there tortuously ending its life. . .
Do not wory that bumbles will cut into honey production, or the pocket books? Bumbles don't store honey, per se, they only gather enough to survive and to feed their young. Bumbles are territorial and mostly feed/gather in small designated areas and even only prefer certain flowers. They usualy take what our bees deem useless, or not yielding enough to bother.
They usualy don't even like competition on the same flowers and will move off. I have kept BB for years and they peacefully coexist with my hives.
Remember, BB too are having problems surviving and they do not have us, humans, to help them out with food and medicine like they insist on helping/doing with our honeybees. . .
Erect some BB houses and/or wooden blocks with holes drilled in them (5 to 7mm size) to house and help out some other (solitary) bees as well. Cause, harmonious and happy coexistence with all species of wild bees can only be of benefit to our endangered honey bees.
Think a bit outside the box, please.
To a gent who has a 10mm upper entrance: Block it down to around 5mm - 6mm at most. A 10mm opening is too big, too high, it will let in snakes, beetles and mice, among countless other things. . . .
Personally I never found the need for larger opening than 3/8 of an inch and even that is too high for my liking. One bee height is all that is needed.
Think defence!? Defending the large opening...
BB will occasionally go into the hive and pick polen from the floor. (bees don't touch it after and if it falls off)
But, BB takes a dangerous gamble by going into the hive. They rarely succeed to take something and get safely out only in weak hives. The strong ones will ball and kill them, if they don't escape in a hurry.
One finds them dead and hairless for the simple reason that bees attempt to drag them out, but they are too heavy and all they accomplish is - they pluck them bald and sometimes mange to tear them to pieces and than drag them out.
There is no danger, whatsoever, from occasional BB that in desperation and hunger ventures into the hive to get something of use for own survival.
Relax people and enjoy in more diversified life around you. . . .