Why is the presence of nectar-rich flowers considered indirect support for the Vestal Cuckoo?

These flowers sustain the host colonies that the cuckoo bee depends upon

While conservationists might aim to help specific pollinator species by planting native, nectar-rich flowers, these efforts often create a cascade effect that benefits parasitic species as well. Because the Vestal Cuckoo requires a healthy, well-provisioned host colony to succeed, the floral resources that sustain the host population are essential. By ensuring that the host species, such as Bombus terrestris, has access to continuous forage, the habitat can support large host colonies. These strong colonies, in turn, are the only ones capable of successfully being exploited by the Vestal Cuckoo, effectively making the health of the host the limiting factor for the success of the parasite.