What does the decline of a specialized cuckoo bee population likely indicate?
Answer
A decline in the specific, closely related host species it exclusively parasitizes.
Some cuckoo bee species are remarkably specialized, targeting only one or two closely related host species; if that specific host population declines, the specialized cuckoo bee population is likely to follow suit immediately.

Related Questions
What reproductive strategy defines cuckoo bees?Why do cuckoo bees often look sleeker and more wasp-like than honeybees?Is "cuckoo bee" a single taxonomic group?What feature do cuckoo bumble bees lack compared to their host relatives?When does a female cuckoo bee typically lay her egg in a host cell?What advantage does the cuckoo bee larva often possess immediately after hatching?What is the typical social structure of almost all cuckoo bees?How does the adult diet of a cuckoo bee generally compare to that of its host bee?What does the decline of a specialized cuckoo bee population likely indicate?What positive ecological implication does the presence of a cuckoo bee often suggest?