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 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 somet ...

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-c ...

, but is sometimes 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 taxon, extant group in the tribe Bombini, though a few extinct r ...

'') in the subgenus ''

Psithyrus Cuckoo bumblebees are members of the subgenus ''Psithyrus'' in the bumblebee genus '' Bombus''. Until the 1990s, ''Psithyrus'' was considered to constitute a separate genus.Williams, P.H. 1994. Phylogenetic relationships among bumblebees (''Bomb ...

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

scopa (; ) is an Italian card game, and one of the three major national card games in Italy, the others being and . It is also popular in Argentina and Brazil, brought in by Italian diaspora, Italian immigrants, mostly in the variation. is also p ...

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

exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that ...

, and saber-like

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

s, although this is not universally true; other less visible changes are also common. The number of times kleptoparasitic behavior has independently evolved within the bees is remarkable; Charles Duncan 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. Characteristic traits of this family are the restriction of their pollen-carrying structure (called a '' scopa'') to the ventral surface of the abdomen (rather than mostly or exclu ...

, and

Halictidae Halictidae is the second-largest family of bees (clade Anthophila) with nearly 4,500 species. They are commonly called sweat bees (especially the smaller species), as they are often attracted to perspiration. Halictid species are an extremely div ...

), 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 distribution, cosmopolitan family of solitary, ground-nesting bees. Most of the family's diversity is located in temperate or arid areas (warm temperate xeric). It i ...

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 The Stenotritidae is the smallest of all formally recognised bee families, with only 21 species in two genera, all of them restricted to Australia. Historically, they were generally considered to belong in the family Colletidae, but the stenotrit ...

, and possibly the

Colletidae The Colletidae are a family (biology), 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 s ...

(there are only unconfirmed suspicions that one group of Hawaiian '' Hylaeus'' species may be parasitic). Cuckoo bees typically enter the nests of

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

-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 ''

'' 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 may refer to: Nature * Brood, a collective term for offspring * Brooding, the incubation of bird eggs by their parents * Bee brood, the young of a beehive * Individual broods of North American periodical cicadas: ** Brood X, the largest ...

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'', a nomadine apid, one species of which is a kleptoparasite of the melittid genus '' Hesperapis'', whereas the other species in the same genus attack halictid bees.

References

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