Ground Nesting Bees
Around this time each year, we begin to receive questions at the N.C. Cooperative Extension of Union County office and via the Extension Master Gardener℠ Volunteers of Union County Growline about bees nesting in the ground and leaving mounds of soil on the soil surface. Often times, if folks have never seen these before they are worried about being stung by the bees or they see the soil mounds and may think it is fire ants.
Not to worry, though. Generally, they do not sting. These little guys are solitary bees and are not colony forming bees like the honey bee and they don’t build a single nest that builds up large numbers by the end of the season like yellow jackets or hornets.
A single female bee builds the nest by burrowing into the ground. She prepares larval cells where eggs will be laid. Mothers provision each brood cell with a mixture of pollen and nectar called bee bread that serves as food for young larvae. After laying an egg she closes the brood cell and starts another. After completing several brood cells, the mother will seal the entrance and leave the nest to begin a new nest. After a few weeks, she will die leaving the next generation safe in the ground. In spring the bees complete development and emerge as adults that dig their way out of the ground and forage for pollen and nectar to provision their own nests. The visual spectacle of these bees is produced largely by males who swarm over nests trying to mate with newly emerged females.
Hundreds of small mounds and swarms of bees often trigger calls to exterminators or landscape professionals. Homeowners fear that they will be attacked and stung as they bend over to pick up the paper and they believe that the bees are actively damaging their yard and want them gone. This is not the case.
These bees prefer to nest in dry, sparsely vegetating areas. Therefore, if you have bees nesting in your lawn it is because the grass is thin and soil dry. The bees don’t make it this way they just take advantage of the conditions. If anything, the bees are providing a valuable service by providing pollination services & aerating the lawn! Because you now understand their habitat preferences, you can take steps to discourage nesting and reduce numbers for next year. You can irrigate during the times the bees emerge & nest and you can take steps to improve your lawn to create a thick stand of grass to encourage the bees to make their nests elsewhere. Native bees are an important part of ecosystems and food production. We should take steps to protect these bees or at least use non-lethal means to encourage them to nest somewhere else.
Join the Master Gardener℠ volunteers of Union County for a Walk & Talk in the Teaching Garden, Thursday, April 18, 2019, at 6 p.m. at the Union County Agriculture Center. The group will meet at the greenhouse. You may even see some bees and other pollinators.