Queens fly from late April (sometimes earlier on the Isles of Scilly,) to early October, workers from mid June to the beginning of October, and males from mid July to early October. The flight season starts later and finishes earlier in Norway (Løken, 1973).
Parasites and predators: Bombus rupestris is a well known social parasite in the nests of this species (Sladen, 1912; Cumber, 1949; Pouvreau,1973; Alford, 1975; Peeters, Raemakers & Smit,1999).