Ground Bees: Important Pollinators That Pose Minimal Problems

Nearly 70% of our wild bee species nest in the ground. They choose well-drained soils in open, sunny areas. Conical piles of fine soil particles usually surround their tunnel entrances (Figure 1). Ground bees are solitary but over several seasons, clusters of burrows develop where soil conditions are favorable.

Ground bees can sting if handled or mashed.  However, they are typically not aggressive and do not respond strongly to perceived threats the way honey bees or ground-nesting wasps do. If practical, ground bees should be left to do their valuable work. Nesting areas can be mowed at night when the bees are not active.

Figure 1. Ground nesting bee resting over tunnel entrance. (Photo: Lee Townsend, UK)

Figure 1. Ground nesting bee resting over tunnel entrance. (Photo: Lee Townsend, UK)

Ground Bee Activities

Ground bees collect nectar and pollen and carry them back to the burrow to feed their developing grub-like larvae. Females will dig several underground burrows, provision them with pollen, deposit eggs, and seal the chambers with soil. The developing bee spends the summer and winter in the soil and emerges as an adult in the following spring. Their activity usually ends by early summer.

Discouraging Ground Bee Nesting

Ground bees select nesting areas because of their characteristics. The long-term answer to discouraging them in undesirable locations is to make the site unacceptable. These bees do not like wet soil so a weekly soaking of the area with the equivalent of about 1 inch of rain may force them to move. Other potential tactics include a thick layer of mulch or shading the site, if practical. Insecticide applications are neither desirable nor particularly effective.

 

By Lee Townsend, Extension Entomologist

 

 

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