Cuckoo bee
Encyclopedia
Bee
Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
lineages which have evolved the kleptoparasitic
Kleptoparasitism
Kleptoparasitism or cleptoparasitism is a form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food...
habit of laying their eggs in the nests of other bees, reminiscent of the behavior of cuckoo
Cuckoo
The cuckoos are a family, Cuculidae, of near passerine birds. The order Cuculiformes, in addition to the cuckoos, also includes the turacos . Some zoologists and taxonomists have also included the unique Hoatzin in the Cuculiformes, but its taxonomy remains in dispute...
birds. The name is technically best applied to the apid
Apidae
The Apidae are a large family of bees, comprising the common honey bees, stingless bees , carpenter bees, orchid bees, cuckoo bees, bumblebees, and various other less well-known groups...
subfamily Nomadinae
Nomadinae
The subfamily Nomadinae is the largest and most diverse group of cleptoparasitic "cuckoo bees" with 31 genera in 10 tribes; they occur worldwide, and utilize many different types of bees as hosts. As parasites, they lack a pollen-carrying scopa, and are often extraordinarily wasp-like in appearance...
. Females of cuckoo bees can be easily recognized in almost all cases, as they lack pollen collecting structures (the scopa
Scopa (biology)
The term scopa is used to refer to any of a number of different modifications on the body of a non-parasitic bee that form a pollen-carrying apparatus. In most bees, the scopa is simply a particularly dense mass of elongated, often branched, hairs on the hind leg...
) and do not construct their own nests. They often have reduced body hair, abnormally thick and/or heavily sculptured exoskeleton
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
, and saber-like mandible
Mandible (insect)
Insect mandibles are a pair of appendages near the insect’s mouth, and the most anterior of the three pairs of oral appendages . Their function is typically to grasp, crush, or cut the insect’s food, or to defend against predators or rivals...
s, though this is not universally true, and other less visible changes are common, as well.
They typically enter the nests of pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
-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 where the hosts are social species (e.g., the subgenus Psithyrus
Psithyrus
Cuckoo bumblebees are members of the subgenus Psithyrus in the bumblebee genus Bombus. Up until recently, the 29 species of Psithyrus were considered to constitute a separate genus. They are a specialized lineage which has lost social behavior, and lost the ability to collect pollen, and are...
of the genus Bombus, which are parasitic bumble bees that infiltrate nests of non-parasitic species of Bombus), the cleptoparasite 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, though a few of them are also what are referred to as "brood parasite
Brood parasite
Brood parasites are organisms that use the strategy of brood parasitism, a kind of kleptoparasitism found among birds, fish or insects, involving the manipulation and use of host individuals either of the same or different species to raise the young of the brood-parasite...
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
Emery's Rule
In 1909, the entomologist Carlo Emery noted that social parasites among insects tend to be parasites of species or genera to which they are closely related. Over the years, this pattern has been recognized in many additional cases, and generalized to what is now known as Emery's Rule...
". Others parasitize bees in different families, like Townsendiella, a nomadine
Nomadinae
The subfamily Nomadinae is the largest and most diverse group of cleptoparasitic "cuckoo bees" with 31 genera in 10 tribes; they occur worldwide, and utilize many different types of bees as hosts. As parasites, they lack a pollen-carrying scopa, and are often extraordinarily wasp-like in appearance...
apid
Apidae
The Apidae are a large family of bees, comprising the common honey bees, stingless bees , carpenter bees, orchid bees, cuckoo bees, bumblebees, and various other less well-known groups...
, one species of which is a cleptoparasite of the melittid
Melittidae
The family Melittidae is a small bee family, with some 60 species in 4 genera, restricted to Africa and the northern temperate zone. Historically, the family has included the Dasypodaidae and Meganomiidae as subfamilies, but recent molecular studies indicate that Melittidae was paraphyletic, so...
genus Hesperapis, while the other species in the same genus attack halictid
Halictidae
Halictidae is a cosmopolitan family of the order Hymenoptera consisting of small to midsize bees which are usually dark-colored and often metallic in appearance...
bees.
The number of times cleptoparasitic 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
The Apidae are a large family of bees, comprising the common honey bees, stingless bees , carpenter bees, orchid bees, cuckoo bees, bumblebees, and various other less well-known groups...
), and 31 lineages parasitizing solitary hosts (mostly in Apidae
Apidae
The Apidae are a large family of bees, comprising the common honey bees, stingless bees , carpenter bees, orchid bees, cuckoo bees, bumblebees, and various other less well-known groups...
, Megachilidae
Megachilidae
The Megachilidae are a cosmopolitan family of solitary bees whose pollen-carrying structure is restricted to the ventral surface of the abdomen...
, and Halictidae
Halictidae
Halictidae is a cosmopolitan family of the order Hymenoptera consisting of small to midsize bees which are usually dark-colored and often metallic in appearance...
), collectively representing several thousand species, and therefore a very large proportion of overall bee diversity. There are no cuckoo bees in the families Andrenidae
Andrenidae
The family Andrenidae is a large cosmopolitan non-parasitic bee family, with most of the diversity in temperate and/or arid areas , including some truly enormous genera...
, Melittidae
Melittidae
The family Melittidae is a small bee family, with some 60 species in 4 genera, restricted to Africa and the northern temperate zone. Historically, the family has included the Dasypodaidae and Meganomiidae as subfamilies, but recent molecular studies indicate that Melittidae was paraphyletic, so...
, or Stenotritidae
Stenotritidae
The family Stenotritidae is the smallest of all formally-recognized bee families, with only 21 species in 2 genera, all of them restricted to Australia. Historically, they were generally considered to belong in the family Colletidae, but it is presently considered that the stenotritids are their...
, and possibly the Colletidae
Colletidae
Colletidae is 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 a cellophane-like lining...
(there are only unconfirmed suspicions that one group of Hawaiian hylaeine species may be parasitic).