Ground bees are any bees that build nests underground, either by digging in loose soil or by taking over the abandoned burrows of other animals. Most are solitary bees living alone, but a few are social. The bees lay their eggs in spring, and the eggs hatch the following spring to start a new cycle.
Ground bees’ burrows can be shallow, above or just under the soil’s surface, or up to 3 feet (1 m) deep underground.
Experts estimate that there are 14 000 species of ground nesting bees in the world, which is about 70% of all bee species. This means that nearly three-quarters of all bees lay their eggs in the ground.
What do ground bees look like?
Ground nesting bees come in many sizes and colors. The biggest measure up to 1.6” (4 cm) and the smallest around 0.25” (0.6 cm) long. Ground bees may be black, tan, yellow, orange, white, blue, green, or a combination of these colors. They have fur on their bodies to collect pollen.
The only thing that makes a ground bee a ground bee is the fact that it builds nests on or underground, where females lay their eggs. Ground bees are not a species but many bee species are ground bees. These bees may share certain traits when it comes to their nests and behaviors, but this is not the case when it comes to their looks.
Types of ground bees
It’s impossible to give a list of 14 000 ground bee species here, but below is a short list of some common types of ground nesting bees followed by pictures of those you might be able to identify in your own backyard.
Some common ground bees in North America that you might have heard of are:
- Alkali bees
- Borer bees
- Digger bees
- Leaf cutting bees
- Miner bees
- Sweat bees
Alkali bees are ground nesting bees found in the western United States, where there is a lot of salt in the soil. These bees are about two-thirds as long as honey bees, with metallic stripes separating black segments in the abdomen.
Alkali bees are solitary bees, which means they live alone in their nest. But they are still social in that they like to build their nests close to each other, and sometimes two sisters live in the same nest.
A female alkali bee digs a main tunnel up to 21” (53 cm) underground, with as many as 20 chambers along the tunnel. It’s in these chambers that she stores pollen and lays her eggs.
The female flies up to 3 miles (4.8 km) from her nest to collect pollen on her back legs during the day, before returning to put the pollen in a chamber and lay eggs.
Bumblebees are ground bees found across most of North America. The bees are large, growing up to 0.6” (1.5 cm) long. Their body and legs are hairy, and they make a buzzing sound as they fly along.
Bumblebees have black and yellow or orange stripes on their body, often with a white tail at the end. Sometimes the tail is red or yellow.
Bumblebees are social ground bees, which means that many live together in a nest. A bumblebee colony also has a queen that hibernates over winter, so there’s no need to make honey.
Bumblebees often build their nests up to 3 feet (90 cm) underground, find naturally occurring holes in the ground to move into, or take over abandoned burrows from other animals, such as rats or rabbits. Other bumblebee species make a nest above the ground, covering it with grass and plant debris.
When spring arrives, the queen stays in the nest to lay eggs while the worker bees and male drones take on the rest of the responsibilities.
The next generation of queens find a safe place to hideout for the winter, and the original queen and her colony die by the end of summer.
Miner bees are ground nesting bees that live across the eastern United States. These bees reach up to ¾ inch in length. They usually have black or brown wings, and their black bodies may have cream, yellow, orange, tan, or white stripes on them.
The bees have fine hairs on their bodies, from their head to the ends of their legs.
Miner bees build nests in dry, well-drained soil. In fact, giving the area enough water and at the right time can get the bees to move to a new nesting site. As solitary bees, they live alone but often build nests close to each other.
A female miner bee digs a tunnel in the ground and uses loose soil to build a turret, which looks a lot like a chimney. This is why miner bees are also called chimney bees.