I know some people who live in the suburbs of a city who had some bumblebees living on their yard. They called an exterminator to get rid of them.
I also watch one of the local gardening "experts" on TV, and listen to a different one on the radio occasionally. People call in to those shows and ask how they can get rid of the bees on their flowers! Sometimes the host will try to explain that bees are important pollinators, but often he will recommend a pesticide to use.
Let me state my position: Bees are a good thing. Bumblebees are especially a good thing.
Sure, they can sting you if you mess with them. Leave them alone and enjoy them.
I have two bumble bee photographs here. I am pretty sure that they are different species, but I have not tried to identify them. The one on the right is on a nice tallgrass prairie flower that is not terribly uncommon. It is called foxglove beardtongue, and it is related to the large flowered beardtongue.
The photo on the left is of a bumblebee on a gentian which is a naturally occurring hybrid between the downy gentian (Gentiana puberula) and the creamy or white gentian (Gentiana alba).
My dad found this flower while he was collecting prairie seeds as a volunteer for The Neal Smith National Wildlife Refuge. The flower had been previously described, but not in Iowa. Did I mention that my dad has no scientific background? I have to say that I am pretty proud of him.
On the left is one of the variations of the hybrid gentian. On the right is a photo of the creamy gentian and the hybrid together. The hybrid is in the upper right.
The creamy gentian typically blooms in mid to late summer, and the downy gentian blooms in late autumn. The hybrid blooms between the two. Other characteristics are intermediate as well, such as the height of the plant and the width of the leaves.
Gentians have large flowers which typically require the insect seeking nectar to crawl down deep into the flower. They are a typical bumblebee flower.