Attracting bees with the right plants is important, but what about inviting them to make a home nearby with attractive ready-to-move-in housing? A custom condo became my project in the winter for solitary mason bees and other native bees of all kinds who come knocking on my door for a place to lay their eggs.
Native bees start looking for homes in early spring so I wanted to have it in “move-in condition” with lots of curb appeal in early March to late May when they were likely to be house hunting. Mud is a necessary component to make partitions and seal the entrance to the nesting tubes. The eggs hatch into larvae and these feed on the ball of pollen left behind for the rest of the year until they emerge as adults. Sources of water and exposed soil to make mud was number one item on my building list for the bees.
When I did my research on solitary native mason bees, I discovered to my surprise that they are a much more efficient pollinator than the social honeybees which were originally imported from Europe with the colonists. Mason bees are one of the few managed native pollinators in agriculture because of this terrific pollinating ability.
Mason bees are about the same size or slightly larger than a honeybee and color is your best way to tell them apart. A mason bee is a dark metallic blue, not striped brown and orange like the honeybee. Being solitary, the mason bee tends to its own brood, instead of having a queen and worker bees like the social honeybee. They seem to appreciate the company of others of their kind and happily build their nests next to each other. They also readily accept the hollow tubes provided by the orchard grower for this purpose. Mason bees don’t produce honey like the honeybee, but collect pollen and nectar just like the honeybee for feeding their young.
Unlike the honeybee, the mason bee flying season is early spring because they can tolerate lower temperatures. The honeybee will only fly when it reaches the 50s, but the mason bee flies in the 40s. Once a mason bee emerges from their over wintering tube, they mate, search for empty holes that are the right size and shape, and start to work. They collect food for their brood, which is tree pollen plus nectar. Females collect this food, bring it to their nests, and knead it into a ball, mixing it with nectar and their own saliva. Once they have a food store that is big enough, they lay an egg on top of this mass and seal-off the chamber or cell with mud. The video below was taken in mid-March and I am not sure of the bee variety.
Then, they start the process all over again until there are five to eight eggs with food, each separated by a thin wall of dried mud. They seal the entrance to the hole with a thicker mud wall. The larvae grow and, by the end of summer, metamorphose into pupae and later into adults, and remain safe and sound inside the nest in a cocoon until the next spring. The new generation emerges in early spring, usually in perfect timing with the blooming peach or apple trees.
Location, Location, Location
For locating your house, look for a south or westerly facing aspect to make full use of the morning sun. Protected from wind and rain by locating the house under a roof overhang, will increase your chances of bees and other insects moving in. A ready source of uncovered soil for the mason bee to use as mud in sealing the eggs, is also important as well as proximity to floral sources. For help in planting the right plants, go to Plant These For Bees.
For an easy mason bee habitat out of cedar wood, I created this simple box with a roof out of an old window box. The house measures 18-inches by 22-inches high with a peaked roof, 6-inches high. The depth of the house is about 4-inches. Using a piece of untreated 4×4 timber and cut rounds of a tree trunk, I cut them into chunks the depth of the house, and drilled holes into the blocks of different diameters. The various sized holes give pollinators a choice in picking out the most suitable hole for their species. This house would be appropriate for different varieties of native bees. The back was just a piece of plywood to give the house stability.
Filling in all the spaces with lotus pods, pine cones, and hollow stems of sunflowers that I cut down from my garden last year took some time. Topping it off with plastic covered hardware cloth, the bee condo was ready to hang and open for business. After the eggs hatch out, I will replace the used blocks and stems with new material and open the house up to new residents next spring.