A solitary bee is a bee that builds and stocks her own nest, with no queen, no colony and no honey. About 90% of bee species live this way, according to University of Arizona Cooperative Extension (December 2022). The Xerces Society (March 2017) adds the detail most backyard guides skip: 70% of native bees nest in the ground, and only the other 30% use tunnels in wood or stems.
That split shapes everything below: who is nesting in your yard, what each kind of nester needs, and where a bee habitat fits in.
What is a solitary bee?
Each female mates, builds her own nest and provisions it herself. In every cell she lays a single egg on a loaf of pollen and nectar, which is what the larva eats once it hatches. Xerces describes this for ground nesters and cavity nesters alike, and Oregon State University Extension (reviewed 2025) lays out the same routine for mason and leafcutter bees. There is no worker caste and no honey to defend, so a honeybee hive is the wrong picture to hold in your head.
Solitary does not always mean alone. Oregon State notes that some species nest side by side and even share an entrance, but every female still builds and feeds her own cells.
Where do solitary bees nest?
The Xerces Society splits native bees into two camps. Ground nesters, about 70%, dig tunnels in bare earth and build several brood chambers along them. Cavity nesters, about 30%, move into an existing tunnel such as a beetle hole in dead wood or a hollow stem. A cavity nester builds from the back of the tunnel toward the front and seals each chamber with mud or bits of plant material as she goes.
Ground nests tend to show up as small mounds of soil with a hole in the middle, according to the University of Arizona, which also says solitary bees are not usually aggressive.
Which solitary bees use a bee habitat?
The cavity nesters. Xerces says man-made nesting habitats are meant for mason bees, leafcutter bees and other cavity nesters, so those two are the ones to know.
Mason bees work with mud. A female seals each cell with a thin mud plug and plasters a thick one across the entrance when the tunnel is nearly full. She picks a hole slightly wider than her body, usually ¼ to ⅜ inch (6 to 10 mm) across, per the University of Arizona.
Leafcutter bees line their cells with circular pieces cut from leaves. If you find neat round bites along the edge of a rose leaf, that is where they went. The University of Arizona calls gardeners' concern about it unwarranted, and Utah State University Extension (May 2021) notes the cuttings do not harm the plant but may change how it looks.
Oregon State says mason and leafcutter bees do not bore holes or otherwise damage structures; they use cavities that already exist.
Timing depends on where you live. In Utah, USU Extension records mason bees flying from March to June and leafcutters from April to October.
Do solitary bees sting?
Only females can sting. The University of Arizona says solitary bees are not usually aggressive and their stings are considered mild, and that a person might be stung when handling a bee roughly or when one becomes trapped in clothing. Watch from a step or two away and keep fingers out of the tubes.
Anyone with a known bee or wasp allergy should treat every stinging insect with caution and follow their doctor's advice. Our full answer is in Do Solitary Bees Sting?
What do solitary bees need in your yard?
Because most native bees nest in soil, a bee habitat covers only part of the picture. This table lines up the three kinds of nester against what each one asks of a yard.
| Nesting type | Share of native bees | What to provide | Source |
|---|---|---|---|
| Ground nesters (mining and digger bees among them) | About 70% | Bare or sparsely planted, well-drained ground; digger bees, for one, prefer morning sun. Go easy on mulch: even a 1-inch layer can be as impenetrable as pavement to these small bees. | Xerces Society (2017); University of Arizona (2022) |
| Stem and wood nesters | Part of the cavity-nesting 30% | Leave dried pithy or hollow stems standing (raspberry, elderberry and hydrangea are examples), and keep some dead wood or a small brush pile. | Xerces Society (2017) |
| Bee-habitat nesters (mason and leafcutter bees) | Part of the cavity-nesting 30% | A man-made tunnel habitat with tubes closed at one end, facing southeast under a roof overhang, plus a nearby patch of bare soil or a container of clay-rich mud for mason bees. | Xerces Society (2017); Oregon State University Extension (reviewed 2025) |
Bees will not lay eggs in a tunnel that is open at both ends, according to Xerces, which is why the tubes in the third row are closed at one end.
Frequently asked questions
Are solitary bees friendly?
They are not usually aggressive. The University of Arizona says mowing and other outdoor work can carry on with few problems.
What do solitary bees do?
Each female collects pollen and nectar, builds her nest cells and lays one egg per cell. In mason bees, the offspring chew through the mud plug and emerge the following spring, according to Oregon State.
Why are there round holes in my leaves?
That is the signature of a leafcutter bee. She cuts circular pieces from leaves to line her nest cells. The University of Arizona calls worry about it unwarranted, and Utah State says the cuttings do not harm the plant.
How do I get rid of solitary bees?
Most yards do not need to. If a nest sits somewhere you truly cannot share, your local cooperative extension office can help identify what is nesting before you do anything.
This article is general information, not medical advice, diagnosis or treatment. For a persistent or worsening symptom, or any concern about your health, speak to a qualified healthcare professional.
Where does the Big Bee Box fit?
The Big Bee Box by WildYard is built for the third row of that table. It is a cedar, bamboo and plywood habitat with nesting tubes in a range of diameters, so different solitary species can each find a cavity of the right width. It measures 6.88 inches wide, 9.85 inches tall and 3.34 inches deep (17.5 × 25 × 8.5 cm), arrives fully assembled and comes with a hook for mounting.
Set it up the way Xerces suggests, with the entrance facing southeast and tucked under an overhang, and within reach of the bare soil or clay-rich mud a mason bee needs, per Oregon State. Our guide to where to hang a bee house covers height, aspect and shelter in full.
Plan on upkeep, too. Xerces points out that man-made bee habitats are not a set-it-and-forget-it purchase: nesting material can collect pathogens and mites over time, and it recommends replacing it every other year. Our seasonal care guide walks through the year.
One fair expectation to set: no bee habitat comes with a move-in date, and this one is no different.
The short version
Solitary bees stock their own nests, about 70% of native bees dig them in soil, and mason and leafcutter bees are the ones that take to tunnels. Bare ground, standing stems and a well-sited bee habitat each suit a different nester. For your next step, read where to hang a bee house, or meet the Big Bee Box.
Keep reading
- Mason Bees vs Leafcutter Bees: Who's Nesting in Your Bee House
- Do Solitary Bees Sting? What to Expect When You Host Them
- Where to Hang a Bee House: Height, Aspect, Shelter and Timing
- More from our bee species guides
Written by The WildYard Editorial Team. Last reviewed October 1, 2026.
