What feature do cuckoo bumble bees lack compared to their host relatives?

Answer

Functional pollen baskets (corbiculae).

A cuckoo bumble bee, which is a cleptoparasite within the Bombus genus, might retain some fluff but lacks the functional pollen baskets, known as corbiculae, found on its host relatives.

What feature do cuckoo bumble bees lack compared to their host relatives?
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