About 80% of the agricultural crops in British Columbia depend on pollination by bees. Unfortunately honey-bee populations have been drastically reduced by mite infestations that originated from an infested honey-bee population that was illegally imported to Vancouver Island. This decline in honey-bee populations and pollination has meant that our native Blue Orchard or Mason bee (Osmia lignaria Cresson) has become more important to agricultural production dependent on pollination. This is mainly because the Blue Orchard bee is an efficient pollinator. For example, only 250 females are required to pollinate an acre of apples and proper care of these bees can ensure that they are not affected by mites.
However, these native bee species need our help to increase their populations because they are so negatively affected by human impact on the land. Because the Blue Orchard bee build their nests in hollow stems or naturally occurring holes, changes to our natural surroundings, through urbanization and logging, reduce natural nesting sites for these native bees. Human-made nesting boxes provide a viable nesting site for these valuable bees and bring many benefits to your garden or property. Nesting boxes are easy to make and we also have ready-made boxes available at our office.
The Blue Orchard Bee Initiative
In 1997, the Cowichan Community Land Trust Society (CCLT) initiated the Blue Orchard Bee Initiative. CCLT is promoting a friendly addition to your farm or garden by informing people about these special bees and how to provide habitat for them. The Blue Orchard Bee (Osmia lignaria Cresson) is a gentle, solitary bee native to western North America that has been getting a lot of attention lately.
“Why all the fuss?”, you might be tempted to ask, thinking the problem of crop pollination will take care of itself. Unfortunately, it is not that simple. As scientists have found, this little insect is very selective in choosing nesting places. Not being a borer itself, it searches for ready-made holes, preferably in pine, fir, or hemlock that are exactly 5/16″ in diameter and 4″ deep. Not finding any it will die.
Nesting boxes provide these bees with much needed nesting sites and can be manufactured either from a 4” x 4” wooden block or wooden trays with channels cut into one side that are then stacked to form a single nesting unit.
Blue Orchard Bee Condo
Wooden block nests are made from untreated 4″ x 4″ wood blocks using a brad point bit. The bee prefers holes spaced ¾” apart from their centers and must be sealed on one end. By drilling through the block and screwing a piece of plywood on the end the sealed end can be removed to make cleaning these nest holes easier and more effective. Ready-made nesting blocks are now available at our office.
Alternatively, nesting trays can be made from pieces of wood measuring 6”x 3 ½” x ¾”. By routering a channel to form a 5/16” groove ending within ½” of the end of each piece of wood, nesting tunnels can be created by stacking these nesting trays. (diagram available at our office) Trays should be tightly bolted or taped together to keep nesting tunnels dark and placed in an additional wooden casing to prevent predation by wasps. Trays have an extra advantage of being easily cleaned of mite infestations. In October cocoons can be removed from trays and cleaned in lukewarm water to remove any mites. Trays can then be properly cleaned and the cocoons can be placed in tissue paper in small cardboard boxes with a small exit hole (the size of a pencil). Bees will emerge from their cocoon in the spring to seek out the cleaned nesting trays.
The best place to hang the box is under eaves with a southern exposure to optimize morning sun and protection from rain. Blue Orchard bees show a preference for sunny sites as long as their nesting holes are shaded.
The bee makes several chambers in each hole, each with an egg and pollen supply. Starting from the end of each hole, they make a bed of pollen (it’s food for the larva) and lay a single egg on top of it. Afterwards, they close this one inch long nursery by erecting a mud wall, separating it from other consecutive chambers, and sealing the last one with an extra heavy mud plug, guarding the eggs from predators. Moist mud must be available nearby to make the rough textured plugs between chambers. Each Blue can lay 35 eggs which would fill a dozen holes in your condo. The larvae hatch and pupate, and develop into adults. These cocoons remain dormant until the next spring. The adults are normally active from late April to early June, but emergence can be delayed to pollinate later crops by refrigerating the nesting blocks in October at 35-40°F. If delaying is necessary, the nests should be gently taken down, kept upright, and put in paper bags with a damp cloth to ensure adequate moisture.
The Ministry of Agriculture recommends an integrated approach to encourage the protection and enhancement of habitat for wild pollinators. Avoiding disturbance to soils and natural vegetation is one way to protect wild bee habitat. Significant drops in wild pollinator populations were noticed in certain areas after serious soil or vegetation disturbances. The goal is to minimize the use of chemical control for economic reasons in some commercial productions. Nesting bee boxes can also help, and are being recommended by our current BCMAFF.
About the Blue Orchard Bee
The Blue Bee The Blue Orchard Bee is only 2/3 the size of the honey bee, that is approximately 1/2 of an inch. It is black with a shiny blue metallic patch on its back and has, just as the honey bee does, a double wing on each side of its body. It has been noted that the blue bee has been mistaken for a house fly and killed. It can be distinguished from that of a house fly by it’s wings; it has a pair of wings on both side where a house fly has one wing. The male Blue even sports a white, whiskery moustache.
Can the Blues be found readily in the wild? As soon as the first blossoms appear (sometimes later) and the weather gets warmer, you should see some activities at your condos. However, if you don’t find anything of this kind, it will be an indication that there are no Blue Orchard Bees in your surroundings. Please contact our office if you are not attracting bees to your condo.
On the other hand, should you see a lot of activity around your condo, please phone us as soon as possible and an extra condo will be delivered to accommodate all of the buzzing crowd.
Watching the bees fly by It’s pure fun to watch the Blues at work. They are simply tireless, making hundreds of flights per day, stashing pollen into the nesting holes. Observing the Blue Orchard Bees could become a great pastime, especially for children, offering them unusual materials for conversations at school.
Safety But, is it safe? One expert, Brian L. Griffin, says that “the Blue Orchard Bee is entirely non-aggressive. It simply will not attack either singly or en-masse” and it “will only sting if squeezed between the fingers or caught under clothing”. Their sting can be compared (experts say) to a mosquito sting. However, people allergic to insect bites should, understandably, exercise great caution.
Contact us – We can help.
Are you interested in raising the Blue Orchard Bee? There’s no work involved, just watch them grow!
CCLT will always be happy to receive news of your bee-keeping progress or requests for additional information.