Valuable as pollinators of shrubs, flowers and trees, the term digger bee refers to several species of bees that burrows into the ground to build their nests. The females construct these underground nests, line them with pollen and deposit their eggs inside. Digger bees are generally docile, and only the females have the ability to sting.
Digger bees prefer dry, sandy soil on flat ground or river banks. Though they sometimes invade lawns, they prefer areas where grass is sparse, such as under the shade of trees or under-watered portions. Unlike honey bees, which form social hives, digger bee females dig solitary nests of only one bee per hole. While females create nests, males cruise overhead looking for mating opportunities. When females emerge from underground, the males mate with them.
Adult digger bees live for only about four weeks and die shortly after mating and laying eggs. The larvae spend the winter in the underground nests, and the following spring they pupate and dig themselves out.
The openings of digger bee nests are surrounded by small mounds of dirt. Although there may be several on a dry patch, they do not damage a lawn. Sometimes homeowners become annoyed by the males that cruise over nesting areas. Rather than use insecticide on these important pollinators, however, it is better to thoroughly water the lawn once a week, and allow the digger bees to move to a drier area.