Everything you ever wanted to know about Blue Orchard Mason Bees…

Everything you ever wanted to know about Blue Orchard Mason Bees…

With declining Honey Bee colonies in North America, people are looking for other ways to pollinate. Mason bees are the perfect answer.

They are not only adorable to watch, but they are super hard workers (well the girls are anyway) and all they do is pollinate, perfect for all your spring blooming needs especially fruit trees.

So here are some facts about these amazing little bees…

Appearance of the bees:

The Orchard Mason Bee appears black but is actually dark metallic green/blue in color. The female is approximately 14 mm in length, robust in appearance resembling a black fly. The male is smaller and more slender, and about 11-12 mm in length. Males are characterized by their long antennae and a tuft of light colored hair in the front of the head. At rest, the bee has its wings flush with its body. Mason bees are effective pollinators because of their pubescence or hairiness. This enables them to carry pollen grains from flower to flower, causing pollination to take place.

Their story:

A number of species of Orchard Mason Bees are native to North America. They occur in different climatic environments but are particularly well adapted in the northern ranges of blooming fruit trees. The common Blue Orchard Mason Bee, Osmia lignaria is found in the B.C.’s southern Interior and coastal areas. It goes under various names including Blue Orchard Bee, Orchard Mason Bee, Orchard Bee, and Osmia Bee.

Orchard Mason bees occur in woodlands and forest edges. They appear in early spring when the first bushes and trees bloom. Cherry, Pear and Apple are particularly attractive but other nectar and pollen sources include Quince, Laburnum and blueberry. Mason bees are fast flyers and display a high bloom visitation rate. Its high activity, even under poor weather conditions, make this insect pollinator particularly attractive for early blooming crops.

Orchard Mason Bees are shy and fly away when disturbed. Even at their nests, female bees will not display defensive behavior though they are capable of stinging. Similar to honeybees, Orchard Mason Bees gather nectar in their ‘honey sac’ while foraging. The nectar is used as energy source and to provision the tubular nest.

Unlike honeybees, Orchard Mason Bees do not have specially modified hind legs called corbicula to store and carry pollen. Instead, pollen is packed underneath rows of stiff hairs called scopa under the abdomen.

Where they live:

Mason bees are solitary insects and complete their lifecycle on their own. Most species are gregarious in that they nest close together. This behavior offers several advantages such as lower predation pressures, increased mating opportunity, and optimized genetic variability through cross breeding. It is this behavior that has offered the opportunity to “domesticate” the Orchard Mason Bee.

Mated females will use existing holes in wood for a nest. Holes with 7 – 8 mm diameter holes are favored. A mud plug is placed at the end of the tubular nest and then she will place up to 20 loads of nectar and pollen at the end of the tube. When sufficient food has been deposited an egg is laid and the cell is sealed with a thin mud plug. The whole process is repeated for each egg and cell she creates until the tube is filled close to its entrance. Often the last cell is left empty to discourage predators. The tube is then closed with a thick mud plug at the entrance. Some wasp species also use tubular nests but their end plugs are often smooth and while the plug of the Mason bee is always rough.

The female Mason bee lives for about one month in the spring and she can produce one or two eggs a day. One tubular nest contains 7 – 11 cells, those laid first in the back of the tube will develop into females…while the few cells nearest to the entrance will be males.

Brood Development:

A few days after the egg has been laid, the larva will hatch and will start feeding on the nectar and pollen reserves. The larva grows very quickly and after 10 – 14 days most of the bee’s food reserves have been consumed. The larva will spin a cocoon and pupate. Later in the summer, the pupa will develop into an adult and will stay in the cell throughout the winter.

In early spring when the first warm days occur the male Bees will emerge from the nest. They chew their way through the mud plug with their strong mandibles. The males will stay near the nests and wait for females to emerge. As soon as females appear, the males will attempt to mate. There is fierce competition between males and sometimes, a female is covered by a number of struggling males. The males only job is to mate with the females and they only live for about two weeks after emerging.

Mud Availability:

As their name indicates, Mason or Osmia Bees need access to mud. If a source is readily available near the nests, the females can be spared a great deal of time and labor. A patch of soil can be kept moist or a small bucket or tray can be filled with wetted soil.

Developing your own Mason Bee Population:

Mason Bees occur in many parts of southern British Columbia. Local populations are often limited by the availability of suitable nesting sites and forage sources. Providing suitable nest sites will attract Mason Bees and allows for the establishment of a sizable bee population in an area.

Alternatively, there are various commercial sources available in British Columbia where a “starter population” comprised of a few tubes can be purchased and installed in the garden with a larger number of empty tubes for nesting sites.

Like Campbell River Garden Centre for instance…we can get you totally set up, come in and see us!

Nests can be made from blocks of wood, 2×4’s and 4×4’s, with holes of 7 – 8 mm in diameter. The length of the hole is not critical but should be 10 – 15 centimeters without opening at the end. It is recommended to use pine or fir but not cedar since the latter contains resins that repel insects. Alfalfa Leaf Cutter Bee boards with holes of at least 6 mm can also be used. If you use wood as the hole, make sure there are not sharp wood pieces in the holes as this can hurt the bees, our Bee guru Gordon recommends burning the wood lightly to get rid of the shards, also the charcoal smell attracts the bees.

Suitable nests can also be created with cardboard and paper straws. Cardboard straws can be bundled together and wrapped in weather resistant tar-paper or inserted into a large plastic tube. Wooden blocks can also be used more efficiently by drilling larger holes of 9 – 10 mm and insert paper sleeves which can be removed in winter.

The following info on how to clean your bees is from Gordon @ masonbeecentral.com:

In October, place blocks or tubular nests in garden shed or garage where there are no temperature extremes and predators. When using paper sleeves, remove from the wooden blocks and place in tray. The tray should be netted or screened and placed in refrigerator or in a cool, dry place until spring. In mid-March, nest blocks should be placed to receive morning sun. Bee activity continues until June and blocks should be removed and placed in the shed by mid July.

Cleaning the cocoons will help control the Pollen mites (Chaetodactylus krombeini) that the Mason bees pickup during their visits to blossoms they have pollinated. The mites then take up residence in the bees nesting hole. The mite will then consume the pollen the Mason bee larvae needs for its full development. If the mite population is excessive they will eat so much pollen the larvae will starve. They may also attack the egg and developing larvae. Providing clean nesting holes every year helps greatly in controlling these pests.

Leave the cocoons in their tubes until November when the bee is fully developed. Remove the paperliners from the cardboard tubes, place the liners in a bucket of water until the glue dissolves making the removal of the cocoons.easy. There will be a lot of debris to clean.

Place the loose cocoons in a cool bucket of water and swirl them around for several minutes, this will separate most of the mud and many mites. Remove the cocoons, dump the water and repeat with clean water. Do this until the water stays fairly clean.  Now prepare a 5% unscented bleach solution and  swirl the cocoons around in it for 5 minutes. Rinse with fresh cool water, let them dry on a paper towel at room temperature and you are finished.

The cocoons should then be stored for the winter. You can store them in the crisper section of your fridge. Most fridges are frost free which will dehydrate the bees and kill them so being in the crisper section will provide them with humidity. Another option is to place the cocoons in a mouse proof container that allows some air movement. A cardboard shoe box place inside a Rubbermaid tote works well. Do not layer the cocoons more than 3 high. Store outside in a shed, carport or some such structure where they will stay dry and not heat up above outside ambient temperatures. Check on them occasionally. Protect from long periods of extreme cold.

Pollen Mites:

Emerging male and female bees sometime have a brown colored mottled covering on their thorax and abdomen. These are large numbers of pollen mites that feed on the pollen that was left after the bee larva entered its pupal stage. These pollen mites are not believed to be injurious to the bees but could possibly limit food availability to the bee larva in spring, and pose a physical hindrance to the adult bee in flight.

Cardboard and paper inserts may offer an effective means to lower the effects of the pollen mites. In winter, tubes can be carefully cut lengthwise and the bees and nesting material can be dipped in a cleansing solution for a short period. Unlike wooden blocks without inserts, cardboard and paper inserts are not reused and can help to prevent pollen mite buildup.

Orchard Pollination:

The Mason Bee has proven to be a very effective pollinator of tree fruit orchards. Their high activity level and tendency to visit different trees optimizes cross pollination. Effective crop pollination can be attained with a much smaller number of Mason Bees as compared to an equal number of honeybees.

For an apple orchard, it is recommended to provide 500 – 1000 filled holes per acre. Assuming an occupancy level of 1.5 females per hole, this would provide for up to 1000 female bees. Females are the primary pollinators as they are the sole nest builders. Males also pollinate but their foraging is only done for nourishment.

Mason Bees often disperse after emergence and seek nesting holes in other areas. For this reason, population increase in a locality may be slow and insufficient to meet the pollination requirements of a crop or orchard. With proper management, a sizable population can be established after several years.

When it’s time to go!!

Usually around the middle of April once it has warmed up fairly consistently it is time to wake your bees up!!! The face of the home should be facing east or south-east. This gives them morning sun which warms them and gets them out pollinating for you that much earlier in the day. They won’t do much unless they are warmed up first :)

Make sure that if you are releasing the bees from a separate container from the home you will be providing that they wake up very close if not on the house where you are wanting them to nest.

Gordon also notes the following:

To release your bees you can insert cocoons into the back end of the tubes.  Care must be taken that the nipple end of the cocoon is towards the front of the hole. The nipple is clearly evident in the above photo. This is the head end. If put  in facing the rear they will hatch out facing the rear and can not turn around to get out. It’s a death sentence. You can fill the tubes with several cocoons, but the small cocoons should be towards the front of the tube as these are the males and they will hatch prior to the females. Place the tubes in the Mason bee home along with fresh empty tubes for the bees to fill up.

You can also temporarily attach a mouse proof container, with the cocoons inside, to the side of the home and let them hatch out of that. Of course there must be a small hole, 5/16 or a bit larger will do it, on the side near the bottom made for them to exit.

If your bees are already in tubes simply place them with fresh empty tubes into the Mason bee home.

That pretty much covers it!!

So now the fun begins, sit back and watch your little bees get to work, they are amazing to watch while they are building the cocoon’s homes.

There is much more to learn about these amazing little bees, and Gordon has a great FAQ page you can go check out @ http://www.masonbeecentral.com/frequently-asked-questions-mason-bees-central



Ministry of Agriculture

Mason Bee Central (Great info and all the stuff you need to get started)

Seabrooke Leckie (Where I got the great shot of the male mason bee and lots of good info on her blog!)

University of Washington Botanical Gardens (Mason bee egg picture)

More Great bee info can be found here:

Lewis County Beekeepers’ Association

Farmboot’s Article Bucket (Cute tin can house)

Inhabitat.com (Teardrop bee house)

Garden Artisans.Com (Bee house Pic and Purchase)

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