Solitary Bees: The Remarkable Pollinators Living in Your Backyard
Most bee species don't live in hives or make honey. Meet solitary bees, the remarkable pollinators nesting in the ground, hollow stems, and small cavities all around us.
When most people picture a bee, they imagine thousands of honey bees living together inside a hive.
But that's only one version of life as a bee.
There are more than 20,000 known bee species worldwide, and the majority don't live in large colonies at all.
Many are solitary.
They don't have worker bees. They don't have enormous colonies. And they generally aren't producing jars of honey.
Instead, a female typically builds and provisions her own nest.
And some of these little-known bees are extraordinary pollinators.
What Is a Solitary Bee?
A solitary bee is a bee that doesn't live within the large, highly organized social colonies we associate with honey bees.
Instead, an adult female generally builds her own nest and provides food for her own offspring.
She collects pollen and nectar, brings it back to the nest, creates a food supply for a developing larva, lays an egg, and seals the nest chamber.
Eventually, a new adult emerges and begins the cycle again.
There may be no queen commanding a colony and no thousands of workers sharing the workload.
It's a very different way of being a bee.
Where Do Solitary Bees Live?
There's no single answer.
Different species have evolved very different nesting strategies.
Ground-nesting bees excavate nests in soil.
Cavity-nesting bees use existing holes and tunnels.
Stem-nesting bees may use hollow or pithy plant stems.
Some species take advantage of holes left behind by beetles or other insects in dead wood.
You might have solitary bees living in your yard without ever realizing they're there.
Are Mason Bees Solitary?
Yes.
Mason bees are among the best-known solitary bees.
They get their name from their use of mud or similar materials to construct partitions between individual brood cells inside their nests.
A female finds an appropriate cavity, gathers pollen and nectar, lays an egg with its food supply, creates a partition, and repeats the process.
Eventually, one tunnel can contain a series of individual chambers.
What About Leafcutter Bees?
Leafcutter bees are another fascinating group of solitary bees.
If you've ever noticed nearly perfect circles or semicircles missing from the edge of a leaf, you may have encountered their handiwork.
Female leafcutter bees cut pieces of leaves and carry them back to their nests.
Rather than eating the leaves, they use the material to construct brood cells.
It's one of the most recognizable signs that solitary bees are living nearby.
Are Bumble Bees Solitary Bees?
No.
This is an important distinction.
Bumble bees are native bees in many parts of the world, but most bumble bee species are social, not solitary.
A bumble bee colony usually begins with a queen that establishes a nest and produces workers.
Their colonies are much smaller and operate differently from perennial honey bee colonies, but bumble bees still have a social structure.
So:
Honey bees = highly social
Bumble bees = social
Mason bees = generally solitary
Leafcutter bees = generally solitary
The bee world contains many different lifestyles.
Do Solitary Bees Make Honey?
Solitary bees generally don't produce harvestable honey.
Honey bees maintain large colonies that can survive across seasons, requiring substantial stored food reserves.
That lifestyle helped create the extraordinary honey-production system humans have worked with for thousands of years.
A solitary bee has a different strategy.
She typically gathers enough pollen and nectar to provision individual offspring rather than building a communal reserve of honey.
That doesn't make solitary bees less important.
It simply makes them different.
Are Solitary Bees Good Pollinators?
Absolutely.
Many solitary bee species are highly effective pollinators.
Some visit a wide variety of flowers, while others have evolved close relationships with particular plants.
Certain solitary bees are also commercially managed to help pollinate agricultural crops.
For example, some mason bees can contribute to orchard pollination, while alfalfa leafcutter bees are important managed pollinators of alfalfa seed crops.
Pollination isn't a competition where one bee needs to be declared the winner.
Different plants benefit from different pollinators.
Are Solitary Bees Aggressive?
Generally, no.
Female solitary bees may be physically capable of stinging, depending on the species, but they don't have a large communal hive filled with honey and brood to defend.
As a result, many solitary species are unlikely to sting people unless they're handled or threatened.
Males don't have stingers.
That makes solitary bees fascinating neighbors to observe in a garden.
How Can You Help Solitary Bees?
One of the best things you can do is provide food and habitat.
Plant a diversity of flowering plants so something is blooming across different parts of the growing season.
Native plants appropriate to your region can be particularly valuable to native pollinators.
You can also allow portions of your landscape to remain a little less manicured.
Bare or lightly vegetated soil can provide nesting opportunities for ground-nesting species.
Dead stems and natural cavities can provide habitat for others.
And reducing unnecessary pesticide use around flowering plants can decrease potential exposure for visiting pollinators.
Sometimes helping bees means doing less rather than more.
Should You Build a Bee Hotel?
Bee hotels can provide nesting habitat for certain cavity-nesting bees, but they need to be designed and maintained thoughtfully.
A large structure packed with nesting tubes isn't automatically better.
Concentrating many nesting bees into one location can potentially create opportunities for parasites, predators, and pathogens.
Materials should remain dry, nesting cavities should be appropriately constructed, and occupied materials need to be managed responsibly.
If you aren't prepared to maintain a bee hotel, creating natural habitat may be an easier option.
Leave some stems standing.
Preserve appropriate dead wood where it's safe.
Allow some bare soil.
Plant flowers.
Nature already knows how to build bee habitat.
Honey Bees and Native Bees Both Matter
Conversations about pollinators sometimes turn into an unnecessary competition between honey bees and native bees.
We don't think that's particularly useful.
Honey bees are extraordinary social insects with a unique relationship to humans, agriculture, and beekeeping.
Native bees represent thousands of species with their own remarkable ecological relationships.
Understanding those differences allows us to appreciate both without pretending they're the same.
At Bee Mission, our work focuses on making beekeeping more economically sustainable for the people who manage honey bee colonies.
At the same time, we believe everyone benefits from understanding and creating habitat for the incredible diversity of pollinators around us.
So the next time a tiny bee appears in your garden, take a closer look.
You may be meeting one of your neighborhood's solitary pollination superstars.
Learn about bees. Create habitat. Support beekeepers. Grow the mission.