From Wikipedia, the free encyclopedia
Andrena is the largest genus in the family Andrenidae, and is nearly worldwide in distribution, with the notable exception of Oceania. With over 1,300 species, it is one of the largest of all bee genera. The typical appearance is brown to black with whitish abdominal bands. Some species have completely black abdomen without bands (e.g. subgenus Melandrena), while others have bands which are centrally interrupted (e.g. in subgenus Micrandrena), and others have red abdomens. Females often show a black triangle at the abdominal apex (tip). In temperate areas, Andrena bees (both males and females) emerge from the underground cells where their prepupae spend the winter, when the temperature ranges from about 20°C to 30°C. They mate, and the females then seek sites for their nest burrows, where they construct small cells containing a ball of pollen mixed with nectar, upon which an egg is laid, before each cell is sealed. Andrena usually prefer sandy soils for a nesting substrate, near or under shrubs to be protected from heat and frost.
