Sweat bees belong to the family Halictidae. The halictid bees are often called “miner bees: because they make underground tunnels where they deposit their eggs.
There are about twelve species of Halictid bees that people call “Sweat Bees”. The sweat bees are small bees. They got their name because they are attracted to perspiration on people and animals. They are not aggressive, but some people receive a sting when they try to brush a sweat bee away.
Halictid bees are not aggressive, but homeowners are sometimes frightened when they find that many bees have nested in the same location around the home.
Halictid bees are not social insects, but scientists often call them “communal”. Many bees work together making the tunnels. Sometimes the female bees work so closely that they use the same tunnel entrance. When the vertical tunnel is finished, each female bee makes her own side tunnel. The side tunnels branch off the vertical tunnel.
When the side tunnel is finished, the female bee brings several loads of pollen and nectar. She forms these into a ball and places the ball in the side tunnel. She places an egg on the pollen ball and seals the chamber with soil.
When the eggs hatch, the larva eats the pollen ball and grows. The larvae that develop from late-summer eggs will usually stay in the underground chamber until spring. They emerge as adult bees.
Halictid bees are valuable as pollinators of crops and flowers. However, homeowners can be intimidated when they see a large number of these bees working in a flowerbed. Many people call a pest control professional rather than trying to control the bees themselves.