Mason Bee Countdown

If I can believe the weather forecast, we should have a series of 'warm enough' days starting next Monday. I've been holding my mason bee cocoons in the deli drawer of my fridge for several months now, in an unmarked Ziploc container with a bit of moist paper towelling - we always got weird looks from houseguests when they discovered the brown bag marked 'Bees' while looking for someplace to stow their potluck food. I believe this is our fifth year of providing a habitat for these solitary pollinators, who help us in return by visiting our fruit trees and berry bushes, which are some of the earliest crops in our garden needing pollination.

Our mason bees are specifically orchard mason bees (osmia lignaria), which have a green/blue metallic colour, rather than the typical black and yellow that comes to mind when people think of bees. They're very docile, with habits very different from the colony-dwelling honey bee. Mason bee females all mate and lay eggs, while producing neither wax nor honey. All they require is a narrow hole or tube in which to lay their eggs, providing their young with pollen and nectar. A female can visit 75 flowers per trip, and it takes 25 trips to create a complete pollen/nectar provision for each egg (Wikipedia). They wall off each individual cell with mud, and leave the larva to develop, and cocoon for hibernation. Similar to other bees, the orchard bee life span ranges from four to eight weeks, at which point she may have visited 60,000 flowers and laid perhaps 20 eggs. This is where I interrupt the cycle, removing the cocoons (ideally in October through February) and rinse them of possible parasites and pests. I store them until I believe the weather will allow enough time for the males to emerge, and mate with the later-emerging females, but need to keep in mind that the cocooned bees are burning through their energy reserves while time passes.

I also provide them a nesting site which I can disassemble and clean for them each year to avoid a buildup of parasites. There's an 'attic' for this bee house, where I can place the cocoons out of the weather; with enough days of warm weather, they emerge through a small hole in the front of the hive, and go about their bee business

 



We've enjoyed keeping our mason bees over the years, though we've never been rewarded with an exceptional growth in our cocoon numbers. Most years we put out about 50-70 cocoons (one year we had to start over due to woodpecker predation), and this year we will be starting with the 80 I removed and cleaned from last year. In the future, I hope to provide more homes for these gentle pollinators.