The term cuckoo bee is used for a variety of different

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfami ...

lineages which have evolved the

kleptoparasitic Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when f ...

behaviour of laying their eggs in the nests of other bees, reminiscent of the behavior of

cuckoo Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals and anis. The coucals and anis are sometimes separ ...

birds. The name is perhaps best applied to the apid subfamily

Nomadinae Nomadinae is a subfamily of bees in the family Apidae. They are known commonly as cuckoo bees. This subfamily is entirely kleptoparasitic. They occur worldwide, and use many different types of bees as hosts. As parasites, they lack a pollen-carr ...

, but is commonly used in Europe to mean bumblebees ''

Bombus A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only extant group in the tribe Bombini, though a few extinct related genera ...

'' subgenus ''Psithyrus''. Females of cuckoo bees are easy to recognize in almost all cases, as they lack pollen collecting structures (the

scopa ''Scopa'' (; literally "broom") is an Italian card game, and one of the three major national card games in Italy, the others being '' Briscola'' and ''Tresette''. It is also popular in Argentina and Brazil, brought in by Italian immigrants, most ...

) and do not construct their own nests. They often have reduced body hair, abnormally thick and/or heavily sculptured

exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton ( endoskeleton) in for example, a human. In usage, some of the ...

, and saber-like

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

s, although this is not universally true; other less visible changes are also common. They typically enter the nests of

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

-collecting species, and lay their eggs in cells provisioned by the host bee. When the cuckoo bee larva hatches it consumes the host larva's pollen ball, and, if the female kleptoparasite has not already done so, kills and eats the host larva. In a few cases in which the hosts are social species (e.g., the subgenus ''

Psithyrus Cuckoo bumblebees are members of the subgenus ''Psithyrus'' in the bumblebee genus ''Bombus''. Until recently, the 28 species of ''Psithyrus'' were considered to constitute a separate genus. They are a specialized socially parasitic lineage whi ...

'' of the genus ''

'', which are parasitic bumble bees, and infiltrate nests of non-parasitic species of ''Bombus''), the kleptoparasite remains in the host nest and lays many eggs, sometimes even killing the host queen and replacing her - such species are often called social parasites, although a few of them are also what are referred to as "

brood parasite Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were it ...

s." Many cuckoo bees are closely related to their hosts, and may bear similarities in appearance reflecting this relationship. This common pattern gave rise to the ecological principle known as " Emery's Rule". Others parasitize bees in families different from their own, like ''

Townsendiella ''Townsendiella'' is a genus of cuckoo bees in the family Apidae Apidae is the largest family within the superfamily Apoidea, containing at least 5700 species of bees. The family includes some of the most commonly seen bees, including bumblebe ...

'', a nomadine apid, one species of which is a kleptoparasite of the dasypodaid genus ''

Hesperapis ''Hesperapis'' is a genus of evening bees in the family Melittidae. There are at least 30 described species in ''Hesperapis''.Michez D. (2008) ''Monographic revision of the melittid bees (Hymenoptera, Apoidea, Melittidae sensu lato)].'' Proc. Net ...

'', whereas the other species in the same genus attack halictidae, halictid bees. The number of times kleptoparasitic behavior has independently evolved within the bees is remarkable; C. D. Michener (2000) lists 16 lineages in which parasitism of social species has evolved (mostly in the family

Apidae Apidae is the largest family within the superfamily Apoidea, containing at least 5700 species of bees. The family includes some of the most commonly seen bees, including bumblebees and honey bees, but also includes stingless bees (also used for ...

), and 31 lineages that parasitize solitary hosts (mostly in

Megachilidae Megachilidae is a cosmopolitan family of mostly solitary bees. Both that their pollen-carrying structure (called a '' scopa'') is restricted to the ventral surface of the abdomen (rather than mostly or exclusively on the hind legs as in other ...

, and

Halictidae Halictidae is the second-largest family of bees (clade Anthophila) with nearly 4,500 species. Halictid species are an extremely diverse group that can vary greatly in appearance. These bees occur all over the world and are found on every continen ...

), collectively representing several thousand species, and therefore a very large proportion of overall bee diversity. There are no cuckoo bees in the families

Andrenidae The Andrenidae (commonly known as mining bees) are a large, nearly cosmopolitan family of solitary, ground-nesting bees. Most of the family's diversity is located in temperate or arid areas (warm temperate xeric). It includes some enormous gener ...

Melittidae Melittidae is a small bee family, with over 200 described species in three subfamilies. The family has a limited distribution, with all described species restricted to Africa and the northern temperate zone. Fossil melittids have been found oc ...

, or Stenotritidae, and possibly the

Colletidae The Colletidae are a family of bees, and are often referred to collectively as plasterer bees or polyester bees, due to the method of smoothing the walls of their nest cells with secretions applied with their mouthparts; these secretions dry into ...

(there are only unconfirmed suspicions that one group of Hawaiian Hylaeus species may be parasitic).

References

*''The Bees of the World'', C. D. Michener (2000) {{Brood parasite Insect common names Bees Brood parasites