They are robust and hairy. They are black and may have yellow, white or orange bands. Two species at the reserve are completely black: Bombus pauloensis (previously known as Bombus atratus) and Bombus cf. morio. To tell them apart the length of the face should be compared. So, we have opted to leave them as Bombus sp. Both species share the subgenus Thoracobombus with a third bumblebee, Bombus bellicosus, also recorded here.

They are excellent pollinators of flowers and cultivated plants. Bumblebees have more advantages over the European honey bees - they tolerate colder temperatures, which increase the number of days and hours devoted to pollination; they get oriented better in low-lit environments like greenhouses; and they visit more flowers than bees do.