In both cities and suburbs, we depend on wild bees such as bumble bee bees and honey bees to pollinate our fruit tree blossoms. Two species of parasitic mites have decimated our wild honey bee colonies (though beekeepers are able to keep mite levels down in managed honey bee colonies). The dramatic reduction in wild honey bee colonies has left us with very few honey bees in our garden.
One solution to this lack of fruit is to provide nests, and nectar and pollen producing flowers for local solitary bees such as the Mason bee. This will increase the number of Mason bees and provide the pollination level we need to get a reasonable fruit crop.
The Mason bee is one of many wild solitary bee species present in North America. It is friendly, and an efficient pollinator. They are called "Mason" because they construct walled-off chambers for each egg they lay. Mason bees begin working early in spring when flowers and fruit trees are beginning to blossom. After emerging from their cocoons and mating, the female Mason bees goes to work collecting pollen and nectar, while also pollinating your blossoms.
The mite problem makes it necessary to clean the house every fall in an attempt to control their numbers and reduce the chances that your bees will infect the next generation. A mite infestiation can apparently decimate a mason bee populations in 2 - 3 years.
Despite the name, adult bees don't actually live in the bee house, they use it for laying their eggs, which grow to adulthood inside their cocoons, and hatch out when temperatures rise in the spring. The above photo shows the trays that sit inside the house. At first it doesn't look like we've had much luck this year......but looking at the back of the trays reveals that there has indeed been some activity in the house this summer!
By removing the large black elastics that hold the trays together, we're able to separate the trays to get a look at what's inside.
In late winter/early spring, I will set the cocoons out in the "attic" of the bee house, where they will pupate and begin their work of mating, laying eggs, and providing pollen and nectar for their developing offspring, continuing the cycle.