By Guest Blogger Keely Kroening
Standing on the banks of the Pareora River at Evan’s Crossing, about to start a fossil hunt we are suddenly surrounded by small black insects are flying everywhere. They settle on our skin but fly away when brushed off.
Later, on a warm summers morning in the Timaru Cemetery, near a bank of hebes and harakeke the small black insects are again flying around, settling on the arms and legs of the gathered crowd, attracted to the flowers some of them hold.
What is this small black winged insect? A quick photo and an observation on iNaturalist (a free identification app) and we have a name. Sweat bees.
Native to New Zealand unlike honeybees or bumble bees and most common the east cost of the South Island, this family of bees are the smallest of our native bees (4-8mm). Named Sweat Bees due to their habit of landing on bare skin to collect the minerals in perspiration, you may well have seen them but swatted them away thinking they were annoying flies.
This semi-social bee makes a nest hole in the ground or in riverbanks with each female laying her own eggs. The nest holes are often grouped together. Sweat bees are one of the many groups of native insects that pollinate our native plants (they pollinate many introduced species too). Surprisingly they carry the same amount of pollen as a bumble bee!
As we inspect the sweat bees landing on a bunch of flowers in the cemetery, we can see the full pollen baskets on their hind legs, golden against the almost metallic black of the bee.
It would be interesting to know if the European settlers that are now buried in the cemetery, or the first farmers of Evan’s Crossing, noticed these wee bees or if they were only interested in introducing and breeding the bees that they were more familiar with from their homelands. Certainly, introduced plants, animals and insects have made their mark on our landscape but if you look closely, you find a small but interesting treasure.
Big Fact List: New Zealand’s Native Sweat Bees
- New Zealand has around four native species of sweat bees in the genus Lasioglossum.
- These bees are native to Aotearoa and evolved alongside our plants and landscapes.
- All are very small, usually just 4–8 mm long, making them easy to miss.
- Because of their size, they are often mistaken for flies.
- They are commonly known as sweat bees.
- On hot summer days, they are attracted to human sweat, which provides minerals such as sodium.
- Sweat bees are gentle and non-aggressive.
- They are very unlikely to sting and pose no danger to people.
- Unlike honey bees, they do not produce honey.
Nesting and Life Cycle
- Female sweat bees make their nests in the ground.
- Nests are often found in bare soil, riverbanks, clay banks, tracks, and cemetery edges.
- Nest holes are sometimes grouped together, forming small colonies.
- Each female lays her own eggs in individual brood cells.
- More than one female may share a nest entrance or nesting area.
- Because of this shared care, sweat bees are described as semi-social.
- Mother bees overwinter underground.
- In summer, new bees emerge as fully grown adults ready to forage and pollinate.
Pollination and Feeding
- Sweat bees collect pollen on their fluffy tummy and hairy legs.
- Despite their tiny size, they can carry large pollen loads.
- They are important pollinators of native plants.
- They also pollinate many introduced plants and garden flowers.
- Sweat bees are not fussy feeders.
- They visit a wide range of flowers, large and small.
- Their small size allows them to reach flowers other bees cannot.
Where You’ll Find Them
- Sweat bees are most common in the east of the South Island.
- They thrive in open, sunny landscapes.
- “Untidy” places often provide the best habitat.
- Cemeteries, river crossings, road edges, and gardens can all support them.
Why They Matter
- Sweat bees help maintain healthy ecosystems.
- They increase pollination diversity, which strengthens plant survival.
- They provide resilience when honey bee numbers decline.
- Their presence is a sign of a functioning local environment.
Sweat bees may be tiny, quiet, and easily overlooked, but they have been pollinating Aotearoa’s landscapes for thousands of years. If you stop, look closely, and give them space, you may discover one of New Zealand’s smallest and most important native pollinators at work.