Megachile
Encyclopedia
The genus Megachile is a cosmopolitan
group of solitary bee
s, often called leafcutter bees. While other genera
within the family Megachilidae
may chew leaves or petals into fragments to build their nests, certain species within Megachile neatly cut pieces of leaves or petals, hence their common name. This is one of the largest genera of bees, with well over 500 species in over 50 subgenera. North America has many native Megachile species, though the imported Alfalfa leafcutter bee (Megachile rotundata) is the only truly important species used for pollination
.
Nests are sometimes constructed within hollow twigs or other similarly constricted natural cavities, but often are in burrows in the ground. Nests are typically composed of single long columns of cells, the cells being sequentially constructed from the deepest portion of the tunnel outwards. The female places a supply of food (pollen or a pollen/nectar mix) and an egg in each cell, then builds a cap and a wall that separates the completed cell from the next one. The larva hatches from the egg and consumes the food supply. After moulting a few times, it spins a cocoon and pupates, often after several months of hibernation as a prepupa. Then it emerges from the nest as an adult. Males, which are typically smaller and emerge in advance of females, die shortly after mating, but females survive for another few weeks, during which they build new nests. Numerous families of wasps and bees will parasitize Megachile nests, most notably including Gasteruptiidae
, Leucospidae
, Sapygidae
, and various cleptoparasitic Megachilids, including the closely related genus Coelioxys.
Various species in the genus, especially those in the subgenus Chalicodoma
and related groups, do not use cut leaves to form the cells as in other species, but instead use fairly dry plant resin, which they carry in their mandibles. The subgenus Chalicodoma
includes the world's largest bee, Megachile pluto
, as well as one of the largest Megachilids in the United States, the recently introduced Asian species, Megachile sculpturalis
.
Megachile species have no lobe (arolia) between their claws and thus are unable to climb smooth (glass) walls.
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
group of solitary bee
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...
s, often called leafcutter bees. While other genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
within the family Megachilidae
Megachilidae
The Megachilidae are a cosmopolitan family of solitary bees whose pollen-carrying structure is restricted to the ventral surface of the abdomen...
may chew leaves or petals into fragments to build their nests, certain species within Megachile neatly cut pieces of leaves or petals, hence their common name. This is one of the largest genera of bees, with well over 500 species in over 50 subgenera. North America has many native Megachile species, though the imported Alfalfa leafcutter bee (Megachile rotundata) is the only truly important species used for pollination
Pollination management
Pollination Management is the label for horticultural practices that accomplish or enhance pollination of a crop, to improve yield or quality, by understanding of the particular crop's pollination needs, and by knowledgeable management of pollenizers, pollinators, and pollination...
.
Gasteruptiidae
The family Gasteruptiidae is one of the more distinctive among the Apocritan wasps, with surprisingly little variation in appearance for a group that contains around 500 species in 9 genera worldwide. The propleura form an elongated "neck", the petiole attaches very high on the propodeum, and the...
, Leucospidae
Leucospidae
The Leucospidae are a small, specialized group within the Chalcidoidea, composed exclusively of ectoparasitoids of aculeate wasps or bees. They are typically mimics of bees or stinging wasps, often black with yellow, red, or white markings, sometimes metallic, with a robust mesosoma and very...
, Sapygidae
Sapygidae
The Sapygidae are a family of solitary aculeate wasps. There does not seem to be a common English name, but Club-horned wasps seems as good a name as any, though various other groups of wasps also have clubbed or thickened antennae...
, and various cleptoparasitic Megachilids, including the closely related genus Coelioxys.
Various species in the genus, especially those in the subgenus Chalicodoma
Chalicodoma
Chalicodoma is a subgenus of the bee genus Megachile in family Megachilidae. It contains the largest known of all bee species, Megachile pluto....
and related groups, do not use cut leaves to form the cells as in other species, but instead use fairly dry plant resin, which they carry in their mandibles. The subgenus Chalicodoma
Chalicodoma
Chalicodoma is a subgenus of the bee genus Megachile in family Megachilidae. It contains the largest known of all bee species, Megachile pluto....
includes the world's largest bee, Megachile pluto
Megachile pluto
Megachile pluto is a very large Indonesian resin bee . As females can be as large as 39 mm long with a wingspan of 63 mm , Megachile pluto is regarded as the largest bee in the world, and has been referred to as Wallace's Giant Bee...
, as well as one of the largest Megachilids in the United States, the recently introduced Asian species, Megachile sculpturalis
Megachile sculpturalis
Megachile sculpturalis, known as the giant resin bee, has a size between and almost . It is much bigger than other leafcutting bees. Native to Japan, it has immigrated to Eastern United States and Ontario, Canada in recent times. It is mainly black with yellow hairs. They will nest next to...
.
Megachile species have no lobe (arolia) between their claws and thus are unable to climb smooth (glass) walls.
Diversity
Approximately 1500 species, this is an incomplete list:- Megachile rotundata, alfalfa leafcutter bee
- Megachile plutoMegachile plutoMegachile pluto is a very large Indonesian resin bee . As females can be as large as 39 mm long with a wingspan of 63 mm , Megachile pluto is regarded as the largest bee in the world, and has been referred to as Wallace's Giant Bee...
, the largest bee in the world - Megachile sculpturalisMegachile sculpturalisMegachile sculpturalis, known as the giant resin bee, has a size between and almost . It is much bigger than other leafcutting bees. Native to Japan, it has immigrated to Eastern United States and Ontario, Canada in recent times. It is mainly black with yellow hairs. They will nest next to...
, giant resin bee - Megachile perihirtaWestern leafcutting beeMegachile perihirta, commonly known as the western leafcutting bee, is a bee in the genus Megachile. The bee is native to western North America, ranging from Nebraska to Texas and Mexico, west to California, and north to British Columbia and Alberta, and often inhabits meadows and orchards...
, western leafcutting bee - Megachile fidelisMegachile fidelisMegachile fidelis, the faithful leafcutting bee, is a species of bee in the Megachile genus.The bee ranges from Montana and South Dakota to New Mexico, west to California and north to Oregon, and often inhabits meadows and gardens...
, faithful leafcutting bee