Lasioglossum – sweat bees (family Halictidae)
by Lisa Schonberg and Mace Vaughan (Xerces Society) and Gretchen LeBuhn (SFSU)
Genus summary: Lasioglossum is a very large genus that occurs worldwide (Michener 2000). There are approximately 280 species in North America (Michener 1994) and 68 in New York State (Danforth & Magnacca 2002). They are often the most common bees in a habitat, but are frequently overlooked because of their small size. Lasioglossum are in the tribe Halictini with the closely related genera Halictus and Agapostemon. These genera are commonly called “sweat bees” because they are known to be attracted to human sweat, which they drink for its salt content (Michener 1994).
Floral preferences: Lasioglossum are primarily generalist foragers, and have medium length tongues (0.1 to 0.2 inches) (O’Toole & Raw 1999).
Nesting habits: Lasioglossum includes species that exhibit the full range of bee social behaviors, including solitary, communal, and social habits. Most species nest in the ground. In social colonies, daughters remain in the nest and help care for the young. Some of the social species have small nests with a single queen and a few workers whereas others build long-lived nests with multiple queens and hundreds of workers. All Lasioglossum spp. line their nests with glandular secretions that are not easily detachable from the surrounding soil (O’Toole & Raw 1999).
Diagnostic characteristics: Lasioglossum spp. are, for the most part, similar in form and structure to each other (Michener 2000). They are slender, tiny to medium bees, dusky black, dull green or blue , with bands of hair on their abdomen . The abdomen is sometimes red (Michener 1994). Females carry dry pollen on scopa (brushes of hair) on their hind legs
Similar taxa: Lasioglossum are similar to Halictus but can be distinguished by the location of hair bands on the segments of their abdomen. Lasioglossum has bands of hair on the innermost portion of each segment, whereas Halictus has bands of hair on the outermost portion of each segment (Michener 2000).
Known conservation concerns:
Interesting fact: Some Lasioglossum line their nest entrance, burrow and cells with glandular secretions of a mixture of chemicals called lactones. Each individual bee has its own unique combination of lactones and contributes this combination to the odor of the nest entrance. This helps workers recognize their own nest when they return from foraging (O’Toole & Raw 1999).