Skip to Content

All About the Mason Bee

There are so many amazing kinds of bees; one of the most interesting types is the mason bee.

These insects have very unique characteristics and nesting habits, and they’re also great pollinators. You can provide places for them to build nests to help them out, and any flowering plants you have nearby will also benefit.

Keep reading to learn all about the incredible Mason bee and what makes them so cool!

Mason Bee,(osmia,Bicornis)

What Are Mason Bees?

Mason bees get their name from the way they build their nests. They will use mud, clay, plant material, or similar materials as though they’re building masonry.

There are many different types of mason bees worldwide and they can tolerate colder climates than many other bees. This adaptation means they can be found in areas where few species of bees are present.

Some species take about two years to reach full maturity, making them among the longest-living bees.

What Do Mason Bees Look Like?

Different types of mason bees have different physical characteristics, but you can often still identify them by sight.

These bees tend to be medium-sized bees with hairs on the thorax and abdomen. Depending on the species, they can be black, orange or yellow, and even metallic green or blue.

Unlike many other bee species that collect pollen on their legs, these bees collect pollen underneath their abdomen. The hairs on both are known as the scopa. They use static electricity to hold pollen on so the bees can pack in as much as possible while out foraging.

While mason bees do have stingers, they aren’t barbed and are relatively small. As a result, mason bee stings are not particularly painful.

Mason Bee Behavior

Mason bees are most active in the spring through to late summer while building their nests and laying eggs in them.

Mason bees are solitary, meaning they don’t live in colonies with a division of labor and large nests. Every female bee is fertile and capable of laying her eggs.

Like other solitary bees, they are known to be docile and will only sting if they feel extremely threatened, even when handled. They don’t have a hive to protect, so they aren’t usually aggressive. If they do sting, it isn’t very painful because of their smaller stingers.

How Mason Bees Nest

Since mason bees are solitary, each bee will create her own nest without help from other bees.

Female bees will seek out small cracks and crevices they can use to make their nests in. Their ideal nesting site is a hollowed-out twig, but they’ll also use enclosed spaces or abandoned nests from other insects.

Whatever they choose, it will be an existing spot and not an area they excavate themselves. When they find a suitable spot, they may augment it with mud or something similar to prepare it for eggs. They use their mandibles to chew up this material and combine it with saliva to sculpt it, then dry solid.

The mason bee will collect pollen and nectar with her nest site selected. Eventually, she will mate with several male bees. A few days after mating, the female bee will begin laying eggs.

Each egg will have its little cell with nectar and pollen for sustenance until maturity. Every cell contains one egg with pollen and nectar and is sealed. The eggs laid first will develop into females, and the eggs closest to the entrance will develop into males.

The bee will continue this process until that nest site is filled. She may then go on to find other places to build new nests.

Male bees will emerge from their cells first and typically wait around nests for the females. Once they’ve mated with a single female they will die soon afterward, having served their only purpose.

Mason Bees’ Place in the Ecosystem

A closeup of a fresh emerged male red mason bee (Osmia rufa) on a purple wallflower (Erisymum Cheir)

Mason bees are among the pollinators responsible for allowing flowering plants to reproduce.

As they visit flowers to gather nectar and pollen, they also disseminate pollen between all these flowers. This dissemination allows these plants to reproduce and is a process the entire planet relies on for life as we know it to survive.

Mason bees, in particular, are essential pollinators because they are native species where they live. This role means they are an integral part of their ecosystems and help ensure that everything in that area can function as it should.

Protecting Mason Bees

Mason bees at an insect hotel in spring

Like other bees and pollinators, mason bees face several threats to their survival.

Pesticide use, particularly overuse, is a major contributor to the drop in their populations. These chemicals don’t discriminate between types of insects, so they are as harmful to the bees as they are to their intended targets.

They are also prone to drifting and ending up in places other than where they were applied.

Climate change and human activity leading to habitat destruction also harm mason bees. In parts of the world where lush green lawns are popular, these bees will find fewer necessary resources and places to make their nests.

With nowhere suitable to live and a lack of flowering plants for them to forage from, they struggle to reproduce successfully.

While they are facing population decline, many ways exist to help mason bees thrive.

Not using pesticides on your property and encouraging others to do the same is very important. If you must use them, be careful to only apply in limited areas when there is no wind or chance of rain to disperse the chemicals.

Finally, don’t bother with creating a huge lawn around your home. Instead, support native plant life and other flowering plants that feed mason bees. Wildflowers, shrubs, fruit trees, and even vegetable gardens benefit pollinators.

Mason Bee Houses

Best Mason Bee Houses

While they aren’t quite like honey bees, you can “keep” mason bees by setting up mason bee houses for them.

They don’t produce anything, but they’re very beneficial for the environment, your garden, and native plants in the area. Providing an inviting place for them to nest will help you spread those benefits.

Mason bee houses are generally made of several small tubes that give the bees an ideal place to make their nests. They’re a great low-maintenance way to help the bees out, but they aren’t all created equal.

Be mindful of the materials used, as harsh chemicals can be harmful or unappealing and won’t be used. The best mason bee houses are simple with tubes that can be easily replaced, like this one.

It’s important to monitor them occasionally and keep them clean. Mason bee houses can become unsanitary or start to house other unwanted pests that can spread to all the bees using the house to nest in. Each tube needs replacing once it’s full to continue providing nest spaces or if it’s hosting pests.

All you have to do is find a nice spot to hang the bee house, ideally somewhere with some protection from the elements. The best time to hang them is in the spring when bees emerge and look for places to build their nests.

Are Mason Bees a Problem?

One of the great things about mason bees is they aren’t something you should be concerned about if you see them around.

They rarely sting and are unlikely to build their nests in problematic spots. It’s usually pretty easy to predict where they’ll want to nest, or you can give them a house to use instead of other places you don’t want them.

You may not notice them at all, but if you do, you don’t need to worry about them. They’re very beneficial and a good sign of a healthy ecosystem, and many farmers and gardeners try to attract them as much as possible.

Appreciating Mason Bees

Mason bees are a truly amazing family of insects.

They’re important to have around to pollinate nearby plants and are among the most successful pollinators. With how well-adapted and widespread they are, they help keep so many plant species going.

The way they build their nests is impressive, and interesting to observe, and you’ll love seeing them use the mason bee house you hang up for them.

Read about honey bees, another incredible type of bee, to understand even more about incredible pollinators.