While many associate bees with hives in trees or human-made boxes, a significant portion of bee species actually make their homes underground. Understanding these ground-nesting bees offers insights into their diverse behaviors and ecological contributions.
The World of Ground-Nesting Bees
A substantial majority, approximately 70% of all bee species worldwide, are ground-nesting. These bees include various types such as mining bees (Andrena species), digger bees (Anthophora species), and sweat bees (Halictidae family).
Most ground-nesting bees are solitary, meaning each female constructs and provisions her own nest independently, without a large colony or queen.
These bees burrow into the ground primarily to create a sheltered environment for their offspring. The females dig tunnels, which can range from a few inches to several feet deep, to lay their eggs and provide a food source for the developing larvae. They often create individual cells within these tunnels, each containing an egg and a ball of pollen and nectar for the larva to consume upon hatching. Ground-nesting bees are often drawn to dry, well-drained, and often sandy or sparsely vegetated soil for their nesting sites.
Understanding Different Bee Nests
Not all bees nest in the soil. Honey bees, for example, are social insects that live in large, organized colonies and typically build their nests in cavities such as tree hollows or in human-made hives. Some Asian honey bee species even construct massive nests in the open, hanging from cliffs or trees.
Bumble bees, another well-known social bee, also do not dig their own extensive burrows for their main nests. They commonly establish their colonies in abandoned rodent burrows or other pre-existing underground cavities. They may also nest in dense grass, compost piles, or other sheltered spots on or just below the ground’s surface.
Coexisting with Ground Bees
Ground-nesting bees are generally docile and pose minimal threat to humans. They are not aggressive and typically only sting if directly provoked, such as when stepped on or handled. The males, often seen flying actively near nest entrances in search of mates, do not possess stingers.
These bees are important pollinators for wildflowers and various crops, including apples and blueberries. To coexist peacefully with ground bees, it is recommended to leave them undisturbed. Avoiding walking barefoot in areas where they are active and understanding their temporary presence during their nesting season can prevent accidental encounters. If their presence is a concern, altering soil conditions, such as increasing lawn density or watering dry patches, can encourage them to find other suitable nesting locations without resorting to harmful pesticides.