Body lengths, female 22 mm, male 16 mm. The queens are large with a black body with a ‘tail’ of red hairs at the tip of the abdomen. The wings are suffused dark brown. Males are smaller with clear wings and many have some dull yellow hairs on the front of the abdomen and on both the front and rear of the thorax. These yellow hairs, however, do not form a distinct band.
It is found along with the host bee, the Red-tailed Bumblebee (Bombus lapidarius), in dry unimproved, grassland, often on the coast.
When to see it
Bombus rupestris adults can be seen from April/May to September.
Takes over the nests of Bombus lapidarius. Mated queens of Bombus rupestris overwinter and emerge somewhat later than the host…. Naturespot