Mated females: up to about a year including winter (estimate from the life cycle). Workers: one summer; not measured. Males: don't survive winter. Colonies: usually annual (UF/IFAS). Name: they drink sweat for the salt (WSU).
How long do sweat bees live?
How long do sweat bees live? Nobody seems to have measured it directly. We searched extension publications, museum species accounts and the research literature and found no published adult lifespan for any sweat bee caste — Animal Diversity Web says plainly that "the exact lifespan of pure green sweat bees is not known." What is well documented is their life cycle, and that gives a good picture:
- Mated females (queens and solitary nesters) are the long-lived ones. In most social species the colony is "annual, lasting one year, and [is] initiated by a single female queen bee, typically in the spring" (UF/IFAS). She was born the previous summer and spent the winter as an adult, so she lives up to about a year — our estimate from that life cycle, not a measurement.
- Workers are born and die within a single summer.
- Males appear in summer and don't survive the winter; only mated females do (UF/IFAS; Yanega 1988).
The calculator shows what's known for the type and caste you choose, and where the month falls in the sweat bee year, without inventing a number.
Development: egg to adult
Development can be quick. In the pure green sweat bee (Augochlora pura), "the time to mature from egg to adult can range from 17 to 40 days," and there are usually two or three generations a year (Animal Diversity Web). Many solitary sweat bees have one generation a year instead (UF/IFAS).
What are sweat bees?
What are sweat bees? Bees of the family Halictidae — "the second largest family of bees", with about 500 species in North America (WSU). They are small to medium-sized, 0.1 to 0.8 inches long, "usually dark-colored and often metallic"; the sweat bee genera Agapostemon, Halictus and Lasioglossum are 0.1–0.4 inches (WSU). Most are "dull to metallic black, with the remaining species being metallic green, blue or purple" (UF/IFAS). Because many don't look like the bees people picture, they're often overlooked (WSU).
They are important pollinators. Most nest underground, often in bare, sunny or sandy soil, and a female stocks each cell with a ball of pollen and nectar and a single egg (UF/IFAS; WSU). The alkali bee, a relative, is a key pollinator of alfalfa (WSU). Wildflowers with patches of bare soil help them (UF/IFAS).
Solitary and social sweat bees
Sweat bees span almost every kind of social life. Species "can be solitary, communal, semi-social, or primitively eusocial," and some switch between solitary and social behaviour "depending on time of year, geographic location, altitude" (UF/IFAS, citing Michener 2007).
| Social sweat bees | Solitary sweat bees | |
|---|---|---|
| Who nests | a queen who founds the nest in spring, then her worker daughters help | each female builds and stocks her own nest |
| Castes | queen, workers, males | females and males |
| Colony | usually annual, one year (UF/IFAS) | no colony |
| Winter | only mated females survive; workers and males die | overwinter as adults or as prepupae (UF/IFAS) |
| Generations a year | workers first, then males and new queens | mostly one; some species 2–3 (UF/IFAS; ADW) |
| Examples | many Halictus and Lasioglossum | pure green sweat bee (Augochlora pura) |
A study of Halictus rubicundus shows how flexible they are: many females from the first summer brood mate, "soon vanish from the nesting site, undergo diapause, and return unworn the following spring" to found their own nests (Yanega 1988). Those females skip being workers entirely.
Sweat bee vs honey bee
Next to a honey bee, a sweat bee is small, often metallic and usually nests in the ground rather than a hive. A summer honey bee worker lives 15–38 days (Remolina & Hughes 2008); a sweat bee worker's life also fits within a single summer, though it hasn't been measured. Instead of storing honey in wax combs, sweat bees mass-provision each underground cell with all the pollen and nectar its larva will need (UF/IFAS).
| Month | Northern Hemisphere | Southern Hemisphere |
|---|---|---|
| January | Mated females overwintering | Summer broods |
| February | Mated females overwintering | Summer broods |
| March | Mated females overwintering | New females going into winter |
| April | Spring nest founding | New females going into winter |
| May | Spring nest founding | Mated females overwintering |
| June | Summer broods | Mated females overwintering |
| July | Summer broods | Mated females overwintering |
| August | Summer broods | Mated females overwintering |
| September | New females going into winter | Mated females overwintering |
| October | New females going into winter | Spring nest founding |
| November | Mated females overwintering | Spring nest founding |
| December | Mated females overwintering | Summer broods |
Months are approximate for temperate regions and vary by species; Southern Hemisphere months are our six-month shift.
Sweat bee nests
Most halictids nest underground, though some nest above ground in rotting wood (UF/IFAS). Each nest cell is usually lined with a waxy substance, probably from the bee's Dufour's gland, and stocked with all the pollen and nectar the larva needs — sweat bees are "mass provisioners" (UF/IFAS). Most gather pollen from many kinds of plants, while a few species specialise on a single plant family (UF/IFAS). Nest shapes differ by group: some dig cells off a slanting tunnel, others build vertical cells or clusters (UF/IFAS).
Cuckoo sweat bees
Not every sweat bee builds a nest. Cuckoo bees (Sphecodes, about 80 species in North America) are "black and red or orange in color, sparsely haired and shiny" and lay their eggs in other bees' nests (WSU). A Sphecodes female usually kills the host's egg or larva before laying her own, and the young cuckoo then eats the stored food (UF/IFAS).
How to recognise a sweat bee
Up close, halictids have "a strongly curved basal vein in the wing", which separates them from other bee families (UF/IFAS). Females carry pollen on hairs on their hind legs; males are often more slender, lack those pollen hairs and sometimes have yellow markings on the face, abdomen or legs (UF/IFAS). Most are slender and dull to metallic black; others are metallic green, blue or purple (UF/IFAS).
Helping sweat bees
Sweat bees "are very important pollinators for many wildflowers and crops, including stone fruits, pomme fruits, alfalfa and sunflower," and their populations "can be encouraged with wildflower plantings and by providing nesting areas" — they typically nest in bare soil in a sunny spot (UF/IFAS). "Minimum tillage and insecticide use will help to increase populations of Halictidae and other soil nesting bees" (UF/IFAS). Native plants also provide overwintering sites (WSU).
Why sweat bees land on people
For the salt. "Halictus and Lasioglossum bees are attracted to human sweat which they drink for the salt content" (WSU) — that's where the name comes from, and Animal Diversity Web says the same of the pure green sweat bee. A sweat bee on your arm on a hot day is having a drink, not attacking.
Do sweat bees sting?
Females can. "Sweat bees sting to defend themselves and their nests," and the sting is painful (Animal Diversity Web). Brush one away gently rather than slapping it. As with any sting, if someone has trouble breathing, swelling of the face or throat or feels faint, call emergency services (UC IPM notes that some people have severe allergic reactions to stings).
How this calculator works
- Type and caste: social (queen, worker, male) or solitary (female, male). The text comes from the shared bee data set used by the bee lifespan calculator.
- Lifespans: because no measured adult lifespan exists in the sources we found, females get "up to about a year" — clearly labelled as our estimate from the life cycle described by UF/IFAS and Yanega (1988) — and workers and males get "not measured".
- Season: the month is matched to the sweat bee year in the table above; Southern Hemisphere months are shifted by six (our assumption).
Frequently asked questions
How long do sweat bees live?
No measured lifespan exists. Mated females live up to about a year including winter (our estimate from the life cycle); workers and males live within one summer (UF/IFAS; Yanega 1988).
What are sweat bees?
Bees of the family Halictidae — about 500 North American species, small and often metallic, that drink sweat for its salt (WSU).
Why are sweat bees attracted to sweat?
They drink it for the salt (WSU).
Do sweat bees sting?
Females can, to defend themselves and their nests, and it's painful (Animal Diversity Web). Brush one off gently instead of slapping it.
Are sweat bees social or solitary?
Both: species range from solitary to primitively eusocial, and some switch with season or place (UF/IFAS).
How long does a sweat bee colony last?
Usually one year; it's founded in spring by a single queen (UF/IFAS).
Where do sweat bees nest?
Mostly underground, preferring loose, sandy or bare sunny soil (UF/IFAS; WSU).
How is a sweat bee different from a honey bee?
Smaller, often metallic, mostly ground-nesting and usually with short-lived annual colonies or no colony at all.
Do sweat bees make honey?
No harvestable honey: they stock each cell with a ball of pollen and nectar for one larva (UF/IFAS).
These calculators give estimates from research and extension figures, for education. Bees are important pollinators — never spray a swarm or a colony. For a swarm or bees in a wall, contact a local beekeeper, a bee-removal specialist or your Extension office (Mississippi State; UGA Extension). If a sting causes trouble breathing, swelling of the face or throat or faintness, call emergency services (UC IPM).