Bombus vestalis

Bombus vestalis is a species of cuckoo bumblebee. Cuckoo bumblebees are a type of bee that exhibits brood parasitism, meaning they lay their eggs in the nests of other bees. Unlike typical bumblebees, cuckoo bumblebees do not have a worker caste and rely on the host species to raise their young.12

The female B. vestalis often enters the nest of a social bumblebee species, sometimes killing the host queen. The host workers are then tricked into caring for the parasitic larvae. Cuckoo bumblebees are generally more robust and less hairy than other bees, and they lack pollen baskets on their hind legs, as they do not collect pollen themselves.12