The term
cuckoo bee is used for a variety of different
bee lineages which have evolved the
kleptoparasitic behaviour of laying their eggs in the nests of other bees, reminiscent of the behavior of
cuckoo birds. The name is perhaps best applied to the
apid subfamily
Nomadinae, but is commonly used in Europe to mean bumblebees
Bombus subgenus
Psithyrus. Females of cuckoo bees can be easily recognized in almost all cases, as they lack pollen collecting structures (the
scopa) and do not construct their own nests. They often have reduced body hair, abnormally thick and/or heavily sculptured
exoskeleton, and saber-like
mandibles, although this is not universally true; other less visible changes are also common.