If you pull the plant, she warns you to go away. Buzz! Buzz! Buzz! If you go away, not pulling the moss, she is working on in peace without any further buzz. Very polite insects these bumble bees, but the females have a sting. You are disturbing a queen. She comes in alone, building up her state. If you've got a diligent queen, you will have a lot of them very soon (approx 50–500). A worker is living max. 4 weeks. Queens are alive up to one year, most of their lifetime is spend in winter, waiting to build a new nest next spring. In September, all of them are dead, except the young Queens. They fly out to search a new place for winter. Short life and a lot of work. Poor Buzzers.