While exploring a golf course on a rather blustery day this week, I was delighted to see dozens of small bees zooming inches above the ground during each break in the clouds and gusty winds. While swarming bees at the margin of play might dismay some golfers, there really was no cause for worry. These were not yellow jackets, honeybees, or other stinging terrors. The very hairy bees were plasterer bees in the genus Colletes. Plasterer bees are relatives of honeybees and bumblebees but, unlike their cousins, these bees are solitary. Rather than living in a communal nest, each female plasterer bee constructs a subterranean gallery of her own to serve as a home for her brood. The interior surface of the burrow is lined with a thin, glossy, translucent material produced by the bee. The habit of coating their galleries gives this bee the common name “plasterer bee”. The burrow is provisioned with nectar and pollen from flowering plants that bloom very early in the spring. Nectar and pollen are the food source for the larvae of the bee that develop with the galleries. Plasterer bees are important pollinators of several native plants. Although they are not considered social insects, they are often abundant in sandy soils with thin vegetation. This was precisely the condition at the edge of the fairway of the golf course. Over large areas of this balding zone, tens of burrows could be found in each square meter of ground. The plasterer bees are not responsible for the thinning of the turf. They simply colonize areas where the ground cover is naturally thin. Although frightening at first glance, these zooming bees are really quite docile. If you should see swarms of small hairy or metallic bees constructing or emerging from galleries in soil of your garden, resist the urge to treat them with insecticides. Several species and families of native pollinators such as digger bees, andrenid bees, halictid bees, and our plasterer bees nest in the ground. Give them a break. Our plants depend on them for pollination.

For more information on plasterer bees and solitary bees found in urban gardens, please visit the following web sites.