Queens are active from mid May to mid October, workers from late June to late August, and males from the end of June to mid or late September. Exceptions include a queen in late March and a male in late May.
Parasites: No Bombus species is reported to usurp nests of this species in Britain or the Netherlands.
Melanism: There is considerable variation of colour shown in ths species. A range of colour morphs re known from the pale coloration of the typical form, to a form in which the collar and metanotal hairs are a dark olive brown, and the hairs on T4-5 are reddish.