Wild Bees
Many species, Andrenidae, HYMENOPTERA


DESCRIPTION

Adult -- These small- to medium-sized bees may be any of a wide range of colors: metallic red, black, blue, green, or copper. Usually no distinctive spots or bands are present. Length ranges from 8.5 to 17 mm.

Egg -- The tiny, white eggs may be up to 2.5 mm long and 0.5 mm wide. Each one is elongate, slightly curved, and attached at one or both ends to a pollen ball.

Larva -- Approximately egg-size when first hatched, the C-shaped larvae grow rapidly and, when mature, are about as long as adult bees. They have a distinct transverse arrangement of bumps across their backs.

Pupa -- Pupae resemble pale, mummified adults and have no protective cocoon.


BIOLOGY

Distribution -- Since several bee species build nests in the soil, bee mounds in turf are nearly cosmopolitan in occurrence although only locally abundant. They are most common, however, in areas with sparse to moderate plant growth, little organic matter, and well-drained soils.

Host Plants -- Essentially beneficial insects, wild bees feed on the nectar of many plants and gather pollen for the larvae to feed upon.

Damage -- Bees do little significant injury to turf. Since they prefer to nest in soils with a sparse vegetative cover, only the unthriftiest of lawns become infested. As the bees tunnel in the soil, the excavated dirt forms mounds 1.5 to 6.0 cm wide and 0.25 to 1.5 cm high. The bees, however, are more often controlled to prevent their damage as stinging pests than to alleviate their detrimental effects upon turf.

Life History -- Wild bees generally overwinter in their soil burrows as adults. They emerge by early April and begin digging new burrows. The burrow consists basically of a vertical shaft 8 to 15 cm deep. The number and size of side tunnels varies with the particular bee species. Unlike some bees, soil- nesting species are not social in that each female makes her own nest, provisions it with food, and lays eggs. There is no worker caste. The bees, however, are gregarious and often nest closely together.

In central North Carolina, wild bees first begin to fly around April 14. Mating takes place soon afterwards and females begin storing pollen in burrows. Furnishing each cell of their burrow with a pollen ball 3 to 5 mm in diameter, females then deposit a single egg on each pollen ball. Eggs hatch in early May in Illinois and perhaps a little sooner in North Carolina. Throughout the summer, the larvae feed and develop within the burrows. Pupation occurs in late summer, usually in August. Adult bees develop sometime in the fall but remain in their burrows to overwinter. A single generation is completed each year.


CONTROL

Wild bees can be controlled by the same methods employed against cicada killer wasps. Consult the agricultural extension service for control recommendations.