Bumblebees are social insects: they live in a colony with a queen and her daughters (the workers). Bumblebees have an annual lifecycle, with new nests being started each spring by queens. The queen bumblebees are very large, and from February onwards can be seen feeding on flowers such as willow catkins, bluebells and lungwort, or flying low over the ground searching for a nest site.
Some species prefer to nest underground in abandoned burrows of rodents, while others nest just above the ground in dense grass or leaf-litter. The queen stocks her nest with pollen and nectar, and lays her first batch of eggs. She incubates them much as a bird would, sitting on the eggs while shivering her flight muscles to produce warmth.
When the eggs hatch the legless grubs consume pollen and nectar, grow rapidly, and pupate after a few weeks. A few days later the first workers hatch from their pupae and begin helping their mother, expanding the nest and gathering food. By mid-summer nests of some species can contain several hundred workers. At this point the queen starts laying both male and female eggs.
The females are fed extra food and become future queens. Both males and new queens leave the nest to mate, and the new queens burrow into the ground to wait until the following spring. The males, workers, and the old queen die off in the autumn, leaving the nest to decay.
REMEDY: If at all possible always leave a bumble bee nest alone to thrive as they are rarely aggressive and their presence is actually beneficial for gardeners and their crop. But, If a nest is situated in a hazardous location, removal may be possible rather than destruction.
Professionals have the ability and training remove these. Only if the location of a nest is dangerous and removal not possible should an insecticide be used to destroy the nest.
Pest Information from the British Pest Control Association.