Mason bees use mud or other natural materials in building their nests, which are made in pre-existing cavities such as hollowed stems, holes made by wood-boring insects, cracks in bark and stones, or even snail shells. Scientists classify mason bees in the genus Osmia and the family Megachilidae. We work two species of mason bees: the blue orchard mason bee, Osmia lignaria, and the horn-faced mason bee, Osmia cornifrons. They fly during early spring and pollinate plants that bloom in the spring such as fruit trees, some berry bushes, and many of our native trees and shrubs.
There are a lot of great things that happen when you host bees in your yard including:
-Increased productions from your fruit trees (apples, pears, cherries, plums, etc.) and berry bushes (raspberries, blueberries).
-Better pollination of our native plants by the mason bees allows them to grow healthier and bigger, which in turn aids in better filtration of our air and water cleaning our environment.
-You can have a direct impact on where your food comes from! Bees that you raise in your backyard will be taken the following year to local farms to pollinate crops that will eventually be sold in our grocery stores.
-Some bees naturally disperse and lay their eggs in your yard, so you are helping to boost local populations of these native bees too.
-Mason bees are gentle: they are a great teaching tool for kids and students to learn about native bees without having to worry about getting stung
-Fun to watch as they pack mud into nesting blocks to protect their developing offspring
You don’t have to worry about getting stung! Mason bees are extremely docile bees. All the females are fertile, which means there is no queen bee for the other bees to protect. They will happily go about their day visiting flowers and carrying mud to the nesting block and not be bothered or aggravated by your presence. You can easily stand in front of the bee house and watch them fly in and out without having to worry about getting stung. Recent experiments out of the USDA Bee Lab have shown that mason bee bodies do not contain any venom which is unlike honey bees or wasps. This means that even if they were to sting you (which might only happen if you were to pinch them or otherwise try to kill them) it would feel more like a mosquito bite than a sting.
Mason bees do not look like a “typical bee”. Blue orchard bees are metallic blue-green and around the same size as a honey bee. Horn-faced bees are slightly smaller, and brown with a furry, golden-orange belly. Male mason bees can be distinguished from females by their smaller size, longer antennae, and light-colored hair patch on their face. Male bees do not have stingers!
Flies, who do not have stingers, mimic bees and wasps to protect themselves from predators but can be distinguished by a few characters. Flies often have large eyes that nearly touch on the top of their head. Flies also have short antennae and only one set of wings. Bees have long, segmented antennae, two separate eyes, and two sets of wings.
Mason bees use mud to pack the holes where they lay their offspring. They go to the back of the hole in the nesting block and place a ball of pollen and nectar that we call “bee bread.” They lay their egg on top of the food source and then build a small mud wall, creating a small cell. They will repeat this process until they have reached the front of the hole, and then plug it with a ¼” of mud that they carry with their mouths. At the end of the springtime, in each hole of the nesting block there will be between 5-8 mason bee offspring behind a plug of mud. When you host mason bees in your yard, you will need to make sure that you mud hole stays wet throughout the season.
In the spring, male and female bees hatch out of their cocoons. The males hatch first, and scent mark the outside of the tube so they know where to return to find the females. After mating, the males have completed their lifecycle. The females then spend the rest of April and May collecting nectar and pollen, pollinating your yard, and laying their offspring in the nesting block.
By June, the adult mason bees you hatched in your yard have completed their lifecycle. Behind the mud plugs are mason bee eggs, which will develop from egg, to larva, to fully formed bees in cocoons by September. We bring them into our storage facility in June and store them at 78 F to protect them from predators and ensure high survival rates.
By September, the bees are now fully formed in cocoons. At that time, we will open the nesting blocks, clean the cocoons, sanitize the blocks, and store the bees in a walk-in cooler for the winter. This is their hibernation time, where their body systems slow and they remain dormant in cocoons until the following spring.
The following March, the bees come out of the cooler (or if the eggs were laid in nature will emerge from your backyard) and begin to fly around your yard. The next generation has now reached adulthood and will begin their lifecycle process all over again.
No, only honeybees make honey, unlike the other 600 kinds of bees that live in the Pacific Northwest. Mason bees are extremely efficient pollinators that are crucial to the health of our ecosystem. They are native to this area, so they are well-adapted to our climate. Mason bees will pollinate about 95% of all flowers that they land on, honey bees can only pollinate about 5%.
Solitary means that all the females are fertile and there is no queen bee. Some bees are ground-nesting, others like the mason bee nest in cavities. The mason bee is a gregarious solitary bee, meaning all the females lay their own offspring, but like to do it near one another, which is why they like to utilize and share our nesting blocks.
There are over 4000 different kinds of native bees in the United States, and we have at least 600 of them in Washington state. We have yet to identify all of the species of bees that exist. This list includes bumblebees, sweat bees, green bees, and carpenter bees among many others. Click here to read about some of the pollinators you might see in your backyard.
The lifecycle of a mason bee takes about 1 year. They begin as eggs in the spring, and develop from egg to larva to pupa to adult bee in a cocoon from June to September. Once in cocoon, they hibernate until temperatures reach around 58 degrees (typically the end of March/beginning of April). The males will fly for about 3 weeks and the females typically fly for 7-8 weeks. So even though we only see them flying around for a few months out of the year, a single mason bee lives for one year.
HOSTING MASON BEES
Hosting mason bees is very easy. You need to provide them with three things:
1. Sources of pollen and nectar during April and May within 300 feet from their nesting block. This could be fruit trees, flower beds, a yard of dandelions or a green belt. Remember, they won’t just stop on your property line, they will travel across the street and into your neighbors’ yards for food too.
2. A nesting block in the sun. We will give you the house to host your bees in, all you need to do is find a sunny spot in your yard to hang the house. To hang, use one nail or screw on the side of your house, fence, or a post in your garden. South facing is great, and you want to ensure that they will get morning sun.
3. A mud source. We have small bags of clay available if you want to supplement your sandy soil with some clay to make it easier for the bees to work with. Instructions for building your mud hole are linked here. Make sure you keep it wet throughout the spring.
WHAT TO DO WITH YOUR BAG OF POWDERED CLAY:
1. Dig a small hole (about a foot deep) somewhere in your yard. It does not need to be right next to where you hung your bee house. The bees will travel 300 feet in any direction from the box searching for pollen and mud.
2. Get the hole wet.
3. Get the clay wet. This can be in your hands or in a bowl. This part is a bit messy as the clay gets very sticky when its wet.
4. Line one side of the hole with the sticky clay about .5″ to 1″ thick. The clay does not need to go all the way around the hole. Mold it as if your a molding a clay bowl. The bees will go into the side of the hole to find mouthfuls of muddy clay.
5. Keep the hole wet throughout May. As temperatures dry out, fill the hole periodically with water when you go out to water your garden. This will keep the clay moist and enable the bees to use it to fill their nesting blocks to protect their developing offspring.
DIDN’T PICK UP A BAG OF CLAY? THAT’S OK.
Dig a hole somewhere in your yard and keep the hole muddy through the season. If at the end of the season only a few holes are filled, consider buying a bag of clay next year to supplement your soil. The bees will thank you!
About a football field in any direction (300 feet or 100 yards) from where you hang the box. That means that when you hang the kit, it doesn’t necessary need to be right next to your apple trees or your mud hole. The bees will seek out foraging resources so it is most important to hang the box in a sunny spot.
When you pick up your kit, we will give you a PVC pipe with two caps on each end. That is where your mason bees start out in while they are still in cocoon. When you get home and mount your kit, take off the tape that is on one of the caps. The mason bees will chew their way out of the cocoons and fly out of the drilled hole. Once the males have hatched, they will begin to scent mark the outside of the tube to know where to come back to find the females. You can leave the tube in the house for the entire season and bring it back to us when you return your bees. If it falls out later in the season, that is OK, the bees will have already emerged and what is left are empty shells. If it does not want to stay put in your house, use some crumpled newspaper around it to wedge it in place.
Those are scent marks left by the emerging male bees. Male mason bees will hatch a few days to a few weeks earlier than the female mason bees. As soon as they hatch, they will scent mark their surroundings with a pheromone marker so that they will know where to return to find the females. You will periodically see them reenter the white tube looking for hatched females.
Absolutely! Of the over 600 different kinds of bees that live in Washington state, each bee depending on size, shape, behavior, and emergence times fall into their own ecological niche. This allows different kinds of bees to forage on different resources and nest in different places so that they can co-habitat in the same places. That means you can host mason bees in your yard and not have to worry about them taking resources away from other bees or vice versa. When planning your garden, it is a good idea to plant a diverse combination of plants to support different kinds of native bees. Click here for ideas on how to select plants for pollinators.
GETTING STARTED WITH YOUR RENTAL KIT
For both mason bees and leafcutter bees, it is important that you hang the bee house in the sunniest spot in your yard. South-facing is ideal as you want to ensure the bees get morning sun and as much sun throughout the day. The bees will travel about a football field (300 feet) in any direction from where you hang the house, so they do not necessarily need to hung directly next to your garden or fruit trees. The houses come with a metal hook on the back so all you need is one nail or screw to hang your house. It will have a slight natural angle down to ensure that rain will not accumulate at the back of the house as it is essential that the nesting block stays dry.
Do not move the house once your bees have begun to emerge. Once the male mason bees have begun to hatch, they will scent mark the outside of the white tube and the nesting block. It is important that you do not move the house because they will be disoriented and not be able to find their way back to the female mason bees. Each year hosting mason bees is an experiment to find the best location for the house so take note of where you hung the house and make adjustments the following year.
Yes! Mason bees are solitary bees which means they do not have a queen to protect so they have no reason to sting you. Kids love watching these bees work in the nesting block and mason bees are a great teaching tool to for children to learn about the importance of pollinators and their role in our agricultural system.
When you return your mason bee kit to us, you are bringing us back the next generation of mason bees. Behind each mud plug, there is anywhere from 5-10 developing mason bees. In June, they are eggs on top of a pollen/nectar food source. They will then go from egg, to larva, to pupa, to an adult bee in a cocoon by September. The bees that you raised in your yard will then be cleaned and overwintered, and then end up either in someone else’s backyard next year, or on one of the farms we work with to pollinate fruit that will end up in our grocery stores. The bees that you hatched out will have completed their lifecycle by June, laying some of their eggs in the nesting block, and some in your backyard to repopulate the local mason bee population in your neighborhood.
THE RENTAL PROGRAM
We provide an option to rent these bees because we want to offer a way for people to support native bees but not have to worry about doing the work the rest of the year. Once you return the bees in June, we put them in our storage facility and keep them at a constant warm temperature to support their development through the summer. We do this to keep them protected from the parasitic mono wasp, as well as to make sure they do not over heat during the summer. Once they are fully developed by September in cocoons, we will open the blocks and wash the cocoons. This insures there are no mites, bacteria, or fungus that could decrease the survival rates of the bees. The blocks are sanitized and the cocoons are moved into cold storage for the winter. If all of these steps are not taken, many of the bees will not survive or the following year will be more likely to spread disease.
We realize that some people want the entire year experience of caring and cleaning mason bees, but for those who want to support bees and get their yards pollinated for a fraction of the cost we want to provide an accessible source. Many of the bees that are propagated through our rental program are then utilized the following year to pollinate fruit trees for local orchards that then end up in our grocery stores. Our rental program offers a way to be involved in your community’s food source and promote healthier urban and rural ecosystems with a minimal commitment.
Yes, there are options to purchase mason bees. We believe in our rental process because there is high potential for spreading disease among native bees when they are not properly taken care of throughout the year. Besides providing nesting and food sources during their flying time, it is crucial to clean the cocoons and store them in your refrigerator over the winter in order to not encourage parasitic populations of pollen mites and mono wasp, both of which cause threats to the development of the mason bee. We have the equipment necessary to carry out this process. It is absolutely possible for those who want the experience of cleaning and storing native mason bees to be successful bee farmers, but we also want to provide an opportunity for many people to support and raise mason bees without having to commit year-round.
We send you an email in November after we have finished cleaning the bees when rental reservations have opened up for the following year. At that time you can go onto our website, create an account if you don’t have one, and reserve your mason bee and/or leafcutter bee kit(s). If you have previously rented from us and still have one of the black houses, reserve the insert instead of the kit.
If you sign up to receive your bees by mail, we will mail your bees to you on your selected ship date. You package will include instructions on what to do when you receive your bees. At the end of the season, you will receive email instructions on how to return your bee kit to our facility in NW Washington State.
If you sign up to pick up your bees at one of our local events in Washington or Oregon state, we will send an email in early March announcing all of the pick-up dates. You’ll host them in your yard for the spring and we will send another email in May with all of our return events.
Once you return the mason bees to us in June you can pick up your leafcutters at the same time. Leafcutter bee returns will take place at the beginning of September.
Yes, there are several other species that can pose threats to the survival of the mason bee. This is why we bring our bees into a temperature controlled room during the summer and a walk-in refrigerator during the winter so that we can control pest population and ensure high survival rates of our bees.
The monodontomerus wasp, or mono wasp, is a parasitic wasp that can be extremely detrimental to mason bee populations. The mono wasp will insert its ovipositor into the mason bee nests and lay its eggs on the mason bee larvae. Once the young wasps hatch, they will eat the developing mason bees inside of their cocoons.
Pollen mites also pose threats to developing bees. When blocks are not cleaned, adult mason bees will carry pollen mites from their surroundings into their nesting cavities. Normally adult bees will knock off most of the mites but there is a section on their thorax behind their head that they cannot reach. Those mites will fall off onto the developing mason bees and consume their food source. If the mason bee egg has no food to consume, it will not survive. To ensure these predators are not spread into local bee populations, we sanitize all of our nesting blocks and clean all of the cocoons. We also try to provide education to the community about why it is important to maintain clean responsible practices when it comes to raising bees.
If you are seeing brown markings on the white tube, that means that the male mason bees have hatched. Sometimes it can take up to 2 weeks after the males hatch for the females to hatch. They then need to mate before the female bees will start to use the nesting block to lay their eggs.
It could be that you do not have adequate mud for the females to use and they left in search of a better mud source. If your soil too sandy or does not remain wet throughout the spring this may be the case. We offer bags of clay to supplement your sandy soil which can sometimes greatly increase your success with hosting bees. You will also want to make sure that the house in hung in full sun, as sometimes the bees will look elsewhere for warmer nesting sites, such as the shingles of your house or in a rockery (don’t worry they don’t do any damage to your property, they only find preexisting holes).
If the mason bees have chosen to not use the nesting block, that is OK as they have found places to lay their eggs in your yard, which will boost the local population of these native bees.
Due to various predators, it is essential that the bees are returned at the beginning of June (for in person drop off) and September for mail return) during our return events and we cannot arrange for individual pick-ups or drop offs. When you rent bees, you are agreeing to returning the bees on time.
We are able to offer our bees at a discounted price because we are able to grow more bees to work with more farms in the Pacific Northwest. If you do not return your bees within the 30 day return window, your credit card will be charged the full retail value of the bee kit ($150). We do not want to do this, but when the bees are not returned, their health is jeopardized and we lose bees.
We recommend getting rid of any bee houses that have been in your backyard for more than a season without being cleaned. If you have a drilled block that does not come apart, and you see mud plugs in it the following is what we recommend to do:
Take the house down and place it in a covered area (under a porch awning for example) with the holes facing up
Place ¼” – ½” of sawdust over the holes
When the bees hatch out, the sawdust will fall in the holes, allowing the adult bees to hatch but not go back into the dirty holes to lay eggs
Provide with a new, clean house nearby for nesting
Alternatively, if you do not have access to sawdust, in the springtime you can place the old house in a sealed cardboard box, holes up, with a small hole cut into the box. The bees will fly out towards the light, but will not return to nest in the old box.
To dispose, burn the block to prevent the spread of pests, or remove from your property.