What is the function of the corbiculae that are absent in the Yellowish Cuckoo Bumblebee female?

To serve as pollen baskets for transporting provisions

The corbiculae, which are smooth, concave areas situated on the hind tibia of standard bumblebees, function specifically as pollen baskets. These structures are essential for the non-parasitic bee colonies because they allow the worker and queen bees responsible for provisioning to gather large quantities of both nectar and pollen. This collected material is vital for feeding the developing brood within the nest. Since the Yellowish Cuckoo Bumblebee is a social parasite, the female relies entirely on the host colony to gather and provide all necessary resources, meaning the parasitic female herself does not need to develop or utilize these specialized transport structures for raising young.