Halictidae

sweat bees, halictid bees

Subfamily Guides

Halictinae(Sweat bees)
Nomiinae(Nomiine bees)
Rophitinae(Shortface bees and allies)

is the second-largest of bees with nearly 4,500 described worldwide. Commonly called sweat bees, many species are attracted to human perspiration to obtain dissolved salts and electrolytes. The family exhibits remarkable diversity in social organization, ranging from solitary to primitively eusocial species, and includes the for which the term "eusocial" was originally coined. Halictids are important of wildflowers and some agricultural crops.

Lasioglossum cressonii by (c) Katja Schulz, some rights reserved (CC BY), uploaded by Katja Schulz. Used under a CC-BY license.

Agapostemon texanus by (c) Don Loarie, some rights reserved (CC BY), uploaded by Don Loarie. Used under a CC-BY license.

Agapostemon nasutus by (c) Francisco Farriols Sarabia, some rights reserved (CC BY), uploaded by Francisco Farriols Sarabia. Used under a CC-BY license.

Pronunciation

How to pronounce Halictidae: /həˈlɪktɪdiː/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

is distinguished from other by the arcuate (strongly curved) basal on the forewing. Members vary greatly in size and coloration, from tiny brassy or brown to brilliant metallic green, blue, or forms. Most species have short tongues. Females are typically larger than males and possess scopae (pollen-collecting hairs) on the hind legs; males often have yellow facial markings. Several of metallic green bees (Agapostemon, Augochlora, Augochlorella, Augochloropsis) are frequently mistaken for cuckoo wasps but can be distinguished by their : sweat bees are common on flowers, fly more directly, and move less jerkily than .

Images

Distribution

occurs on every continent except Antarctica. The has been documented from Baltic amber (96–75 million years ago) and Dominican Republic amber, with the oldest fossil records dating to the Early Eocene.

Diet

halictids feed on nectar and pollen. All except kleptoparasites are pollen feeders. Many species are , though some are oligolectic (specialized to particular plants).

Life Cycle

Most nest in the ground, excavating burrows in soil ranging from sand to clay; some species nest in rotting wood. Females mass-provision their young: a waterproof is stocked with a mass of pollen and nectar, an is laid upon it, and the cell is sealed. The larva receives all food at once rather than being fed progressively as in honey bees. Some species line nest tunnels with lactone secretions that serve as chemical signatures to help return to the nest.

Behavior

Many halictid exhibit eusociality with and , though the division of labor is often less rigid than in honey bees. Social organization varies widely within the and can be facultative, shifting with environmental conditions such as temperature, food availability, and season. Some species are solitary, others communal or semi-social. Several , notably Sphecodes, are kleptoparasites that enter , consume the host , and lay their own egg in its place; this has evolved independently at least nine times within the family. Some species in Lasioglossum (subgenus Sphecodogastra) and Megalopta are or , with greatly enlarged ocelli.

Ecological Role

are significant of diverse flowering plants, including wildflowers and some agricultural crops. Their ground-nesting contributes to soil aeration and nutrient cycling.

Human Relevance

Halictids are generally beneficial insects that contribute to pollination services. Some , including the alkali bee (Nomia melanderi), Lasioglossum vierecki, and L. leucozonium, are important crop . The "sweat bee" derives from their attraction to human perspiration; they seek dissolved salts and electrolytes and are harmless unless trapped or swatted. Only females can sting, and the sting is minor. They are often confused with syrphid flies (hover flies), which also visit humans for sweat but are flies, not bees.

Similar Taxa

SyrphidaeHover flies are frequently mistaken for sweat bees due to similar size, coloration, and attraction to human sweat. Syrphids have only one pair of wings (bees have two), lack scopae on legs, and often have large that meet at the top of the in males.
ChrysididaeCuckoo wasps are often confused with metallic green halictids such as Agapostemon and Augochlorini. are less commonly found on flowers, move with quick jerky motions, and lack pollen-collecting scopae on the hind legs.

Misconceptions

Despite their name, sweat bees do not produce sweat; they consume it. They are not aggressive and sting only when trapped or handled roughly. The is not uniformly social—social organization varies from solitary to eusocial depending on and environmental conditions.