''Andrena'' is a genus of bees in the family

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 ...

. With over 1,500 species, it is one of the largest genera of animals. It is a strongly

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

group that is difficult to split into more manageable divisions; currently, ''Andrena'' is organized into 104 subgenera. It is nearly worldwide in distribution, with the notable exceptions of

Oceania Oceania ( , ) is a region, geographical region including Australasia, Melanesia, Micronesia, and Polynesia. Outside of the English-speaking world, Oceania is generally considered a continent, while Mainland Australia is regarded as its co ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. Bees in this genus are commonly known as mining bees due to their ground-nesting lifestyle.

Morphology

''Andrena'' are generally medium-sized bees; body length ranges between 8 and 17 mm with males being smaller and more slender than females. Most are black with white to tan hair, and their wings have either two or three submarginal cells. They carry pollen mainly on femoral scopal hairs, but many ''Andrena'' have an additional propodeal corbicula for carrying some pollen on their thorax. C. D. Michener (2007) ''The Bees of the World'', 2nd Edition, Johns Hopkins University Press. They can be distinguished from other bees by the broad velvety areas in between the

compound eye A compound eye is a Eye, visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidium, ommatidia, which are tiny independent photoreception units that consist of a cornea, lens (anatomy), lens, and p ...

s and the antennal bases, called facial foveae. Some other genera in the family Andrenidae also have foveae though, so the best identifying feature unique to ''Andrena'' is the presence of a ring of hairs on the underside of their face called the "subgenal coronet".

Life history

All ''Andrena'' are ground nesting, solitary bees. They seem to have a preference for sandy soils. The genus includes no parasitic or social species, though some nest communally or in aggregations. After mating, each female bee digs a burrow, excavating a series of small chambers called "cells", lined with a shiny secretion, which she provisions one at a time with nectar and pollen to form firm, round pollen masses for the larvae to eat. Soil from the excavation process forms a small

tumulus A tumulus (: tumuli) is a mound of Soil, earth and Rock (geology), stones raised over a grave or graves. Tumuli are also known as barrows, burial mounds, mounds, howes, or in Siberia and Central Asia as ''kurgans'', and may be found through ...

around the nest entrance. Larvae do not spin a cocoon and they overwinter as adults. They typically have one generation per year and adults are only active for a few weeks. ''Andrena'' nests are attacked by many other insects including brood parasitic bees, blister beetles, various parasitic flies, and

Strepsiptera The Strepsiptera () are an order of insects with eleven extant families that include about 600 described species. They are endoparasites of other insects, such as bees, wasps, leafhoppers, Zygentoma, silverfish, and cockroaches. Females of most s ...

. Many ''Andrena'' are host-plant specialists, in which a species visits flowers of only a single or a few closely related plants. Oligolectic ''Andrena'' have specialized on many different plant groups and have morphological and behavioral adaptations that suit them for their pollen preference. For example, all members of the subgenus ''Callandrena'' specialize on pollen from the plant family Asteraceae and have highly branched, fluffy scopal hairs to hold aster pollen. According to Larkin ''et al.'' 2008,

oligolecty The term oligolecty is used in pollination ecology to refer to bees that exhibit a narrow, specialized preference for pollen sources, typically to a single family or genus of flowering plants. The preference may occasionally extend broadly to mu ...

was the basal trait for ''Andrena'' and a generalist diet has evolved multiple times across the genus.

Distribution

''Andrena'' are common in temperate regions of Europe, Asia, and North America and most diverse in areas with a Mediterranean climate. A small amount of species are present in sub-Saharan Africa, and there are none in South America, Australia and nearby islands, or Madagascar.

Species

Partial list of species: *'' Andrena angustitarsata'' * '' Andrena agilissima'' *'' Andrena accepta'' *'' Andrena androfovea,'' Southwestern United States * †'' Andrena antoinei'' Michez & De Meulemeester, 2014, late

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

of France *'' Andrena auricoma'' *'' Andrena barbilabris'', Europe, Northern Asia and North America *'' Andrena bicolor'', Western Palearctic *'' Andrena carbonaria'' *'' Andrena cineraria'', Europe *'' Andrena flavipes'', Europe and central Asia *'' Andrena fulva'', Europe *'' Andrena ghisbaini'', Europe (endemic to southern Spain) *'' Andrena hattorfiana'', Europe *'' Andrena haemorrhoa'', Europe *'' Andrena lauracea'', known only from 4 specimens in

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

and

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

, in the central United States *'' Andrena lagopus'', Palearctic *'' Andrena salicifloris'', western North America *'' Andrena milwaukeensis'', United States and Southern Canada *'' Andrena hadfieldi,'' Southwestern United States See comprehensive separate list. Andrena accepta.jpg, ''A. accepta'' Andrena nasonii. saxifrage.jpg, ''A. nasonii'' Early mining bee (Andrena haemorrhoa) Cumnor.jpg, ''A. haemorrhoa'', Early mining bee,

Oxfordshire Oxfordshire ( ; abbreviated ''Oxon'') is a ceremonial county in South East England. The county is bordered by Northamptonshire and Warwickshire to the north, Buckinghamshire to the east, Berkshire to the south, and Wiltshire and Glouceste ...

Andrena Subgenus Gonandrena.jpg, ''Andrena'' Subgenus ''Gonandrena'', dogwood andrena Andrena nida, m, face, Montgomery Co 2015-12-01-11.55 (24641006220).jpg, ''A. nida'' Plos One 108865 Fig 6 A Andrena antoinei.png, ''A. antoinei'' fossil

References

External links

Bugguide.net
Andrena, North American species only).

diagnostic photographs and information
Andrena Identification Guide (female)Andrena Identification Guide (male)List of SpeciesWorldwide Species Map
{{Taxonbar, from=Q517165 Bee genera Taxa named by Johan Christian Fabricius Articles containing video clips