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 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 and other bees, I discovered to my surprise that they are a much more efficient pollinator than the social honey bees 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.
Differences Between Mason & Honey Bees
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 honey bee. 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 honey bee, but collect pollen and nectar just like the honey bee for feeding their young.
Home gardeners can attract mason bees in their own gardens by placing home-made bee houses and blocks in their own yards. Scroll down to see my version of a DIY house for mason bees.
Unlike the honey bee, the mason bee flying season is early spring because they can tolerate lower temperatures. The honey bee will only fly when it reaches the 50’s, but the mason bee flies in the 40’s. 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.
Nesting House Basics
Since many wild bees are sedentary, residing where they originated, they will stay nearby, provided there are suitable nesting sites. The greater the variety of species and population density in the area, the faster the colonization.
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.
Easy DIY Mason Bee House
For an easy mason bee habitat out of wood, I created this simple box with a roof out of cedar wood. The house measures 18″ x 22″ high with a peaked roof, 6″ high. The depth of the house is about 4″. I took an untreated (no chemicals) 4 x 4 timber and cut it 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.
Chas and Mark Simmons collaborated on making 3 artistically beautiful houses using all recycled materials. Taking about 4 hours to make the frames- pallets, screens from the safety guards of greenhouse fans, and other repurposed materials were all put to good use. But the time consuming part, 4 days, was collecting all the materials to go inside and paint them. Everything used in the construction was used from the property of Cavanos’ Perennial Nursery, where they both work. Once the weather warms up a little, they will be hung up where the bees have a entire nursery to pick from for their floral sources.
Craft paint and sealer was used on the edges to make these houses pop!
Move In Day
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.
Tubular is the main feature that mason bees are interested in. Finding something round is critical for their egg-laying success. I keep looking for tubular shaped objects, like bamboo, sunflower stems, or any large stem with a cavity in the center. Even paper straws would work.
Go to www.crownbees.com to browse ready-made houses and tubes, if you don’t have time to build from the ground up. You can also get an attractant pheromone that will be sure to entice the mason bees to nest in their new home. The site is also a wealth of information about many native bees.
Crown Bees recommends that once summer is over, that you harvest the mason bee cocoons and place them in a humidity tray with a moist cloth in your refrigerator to keep conditions right for surviving until next spring. They would still hatch outside, but predators and disease are more likely to kill them.
When warmer weather rolls around, bring the humidity tray outside in the warmer air and wait for the cocoons to hatch and release the bees. I ordered some cocoons from them and a few hatched in transit which I released outside when they came.
There are many other strategies that you as a homeowner can do to help out with our pollination crisis. See my action plan outlined at Sex in the Garden.