Small Mounds of Soil Caused by Ground-Dwelling Bees

Small Mounds of Soil Caused by Ground-Dwelling Bees

by | Mar 20, 2020

Ground-dwelling bees get a lot of attention in late winter and spring as they create large numbers of small mounds in local lawns and landscapes.

Many people become concerned as they see these bees hovering close to the ground out in their lawns and landscapes. But these bees are interesting, docile, beneficial and are unlikely to sting.

These bees are known as andrenid bees or mining bees. Andrenid bees are solitary. As the name implies, they live alone. However, they may nest in close proximity to one another but they do not form a colony or hive. They produce individual mounds with a small entrance hole. The bees are approximately ½ inch in length with a black body.

Richard Sprenkel, retired UF/IFAS Entomologist, explains their biology in today’s article.

“After mating in late winter and early spring, the female selects a site that has dry, loose soil with sparse vegetation. She excavates a vertical shaft in the soil that is approximately the diameter of a pencil and up to eighteen inches deep. Off of the main shaft, the female will construct several brood chambers that she lines with a waterproof material. The female bee provisions each brood chamber with pollen and nectar on which she lays an egg. The pollen and nectar sustain the larva until fall when the overwintering adult is formed. Early the following spring, adult bees emerge from the ground to begin the cycle again. There is one generation per year.”

The small mound of soil that is excavated from each burrow brings additional attention to the activity of the bees. As males continue to hover in the area of the burrows looking for unmated females, the bees appear more menacing than they actually are. Andrenid bees have a tendency to concentrate their nests in a relatively small area. The openings to the underground burrows may be no more than three to four inches apart.

The threat of being stung by these bees is usually highly overrated. The males cannot sting and the females are docile and not likely to sting unless stepped on, handled or threatened. While entrances to the tunnels and excavated soil may appear disruptive to the lawn, they usually are not damaging. It may appear that the grass is thin because of the bees but it is more likely that the bees are in the area because the grass was already thin. Control is usually not necessary. Because the andrenid bees forage to gather pollen and nectar, they are actually beneficial. They serve as pollinators this time of the year.

 

**** Photo Credited to UF / IFAS Extension Jackson County courtesy of Josh Thompson****

Let That Digger Bee Be

Let That Digger Bee Be

by | Mar 26, 2018

Digger bees resemble honey bees, although they do not sting, and would only bite if mistreated. Photo by Molly Jameson.

Have you noticed many little dirt piles that resemble mini ant mounds around your yard? Well, fear not, for these mini mounds are made by digger bees who are excellent, yet ephemeral, early-spring pollinators.

These solitary ground-nesters are native to our area and only appear for four to six weeks to raise their offspring. Although they do not produce honey, they resemble honey bees in size and shape. They also do not sting and would only bite if they were handled roughly.

Female digger bees build their nests close together, creating clusters of many small mounds. Photo by Molly Jameson.

Otherwise known as miner bees, females create their underground cylinder-shaped nests in dry, well-drained soils, often right next to each other, creating patches of many mounds in a small area.

These bees will pollinate many early-spring blooming flowers – a bonus for gardeners – as they collect pollen to add to each cell that they excavate. They then lay their eggs on these pollen masses, cap the cells with clay, and complete their life cycles. The eggs hatch about five days later and emerge from the chamber created by their mothers.

While digger bee mounds may detract from an otherwise tidy lawn, they will do no harm, and can actually be beneficial, in that they improve air, water, and nutrient percolation. If you feel you must discourage their presence, simply run a sprinkler over the area as their season approaches. They prefer dry soil rather than wet soil and will look elsewhere to build their nests.

But better yet, take a seat on your front or back porch, pour yourself some lemonade, and take in the soothing hums of their wings as they do their work.