Agapostemon

Photo by Ron Hemberger

Agapostemon – green sweat bees (family Halictidae)
written by Lisa Schonberg and Mace Vaughan (Xerces Society) and
Gretchen LeBuhn (SFSU)

Genus summary: The genus Agapostemon is widespread and abundant throughout North and South America. There are 44 species in total (Michener 2000). There are 5 known species in New York State (Danforth & Magnacca 2002, Mitchell 1960) and about 5 in the northwestern portions of both the U.S. & Canada (Stephen et al. 1969). They are most diverse and abundant in temperate regions and southwestern U.S. deserts. Agapostemon are in the tribe Halictini, which also includes Halictus and Lasioglossum. These genera are commonly called “sweat bees” because they are attracted to human sweat and drink it for its salt content.

Floral relations: Agapostemon are floral generalists (Stephen et al). Like other members of the family Halictidae, they are short-tongued (Michener 2000). Males can be observed flying slowly around flowers looking for females.

Nesting habits: Most Agapostemon are solitary ground nesting bees. Some species nest communally; two to 24 females share a single nest but each individual still builds and provisions its own nest cells. Agapostemon nest in the ground in deep vertical burrows or soil banks (O’Toole & Raw 1999).

Diagnostic characters: Agapostemon are robust, strikingly colored metallic green or blue bees. They are medium sized and 0.3 to 0.6 inches long (Michener 2000). Most species have a bright metallic green head and thorax and a striped abdomen; some females are entirely bright green or blue. Females carry pollen on brushes of hair (scopa) on their hind legs . Female Agapostemon are relatively fast-flying bees but, males fly much more slowly because they are often searching flowers for females.

Similar taxa: Augochlora pura, a species that occurs north to southern Oregon, is also metallic green. However, the Agapostemon male has yellow and black-banded abdomen whereas Augochlora does not (Stephen et al). Other similar taxa are Osmia,, some wasps, and orchid bees (Tribe Euglossini).

Known conservation concerns:
Interesting fact:
Additional resources: Roberts (1969).

World map of species of Agapostemon

Key to Agapostemon at DiscoverLife