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A Year in Mason Bee Keeping

Mason Bee CocoonIn late winter, hang your mason bee nest against a wall in a sunny location that has morning light. Placing it about eye level is best. That way you can watch them coming and going! 

Consider putting the cocoons out near or on the nest in early March. Choose a warm sunny day with little wind. If using the bees for pollinating your fruit trees, wait until the trees are about 25% in bloom. Otherwise look around your garden and neigbourhood to see what is flowering. Imagine your bees visiting 17 blooms a minute in a 100-meter radius from the nest. Is there enough forage? If so, bring out the bees.
 
Hang around for a half hour or so and watch for the males to emerge. They are a little smaller than the females and have a white tuft of hair on their foreheads. They are cute! Being male, they have no stinger and so are perfectly safe to gently handle as they emerge. They will sit on your hand for a minute before flying off for a long awaited breakfast. If they leave a bit of orange sticky stuff behind don’t be shocked; just a little bee poop as a memento… If you are very lucky and very patient you might find the males huddled together beneath a flower blossom having a snooze.
 
The females will stay in their cocoons for another few days or weeks, depending on the weather. Hopefully sooner than later. After emerging they will mate almost right away, but it takes a few days for their ovaries to mature. Until then they seem to disappear. Eventually, if you have the right conditions, you’ll see them busying themselves around the nest.
 
They’re hard to follow, being such fast fliers. You can spot them around fruit tree flowers if you wait long enough. In the afternoon they can be seen with their back ends sticking out of the nest tubes, having a siesta.
 
For greater success helping your bees, make sure there is exposed clay nearby. Unfortunately, one year my bees used construction-grade sand to make their walls. The next spring the newly emerged bees couldn’t chew their way out. Since then, I haven’t left this to chance. A small tray of water with rocks in it for landing on also increases the bees’ ability to lay eggs. Planting a diversity of flowering material, in terms of colour, height, type of flower, and time of blossoming will give the bees more opportunities for forage.
 
Adult female bees lay a single egg and deposit a ball of gathered pollen and nectar. Then they wall that chamber closed before laying the next egg and depositing the next food ball. Being parthenocarpic, mason bees lay fertilized eggs—females at the back of the nest tubes, and unfertilized male eggs at the front.
 
Usually by the end of June, this year’s adult females are dead. You will notice a drop-off in activity around the nest. At this time, it’s worth bringing the nest indoors, and placing it with the entry holes pointing up somewhere out of the way like on top of the refrigerator. This will ensure that the larvae in each chamber will be in contact with their stored food supply. By bringing it indoors, you can prevent the developing larvae from being eaten by birds or parasitized by wasps. Don’t worry about it being too warm, as the larvae need time to spin their cocoons and turn into pupae.
 
By the end of August the larva have pupated inside their cocoons and are already fully mature. They will stay in this dormant condition until the following spring when the cycle begins anew. By late September, it will be safe to open the nesting tubes to wash the cocoons.
 
Gently take the tubes apart and float the waterproof cocoons in a bowl of cold water. Delicately rub them back and forth with your fingers until no more mud and mites can be seen clinging to the cocoons. The mites are very small and look like rust, turning the water very red. Cocoons containing live healthy bees tend to float on the surface of the water. Keep the sinkers separate from the good cocoons to see what emerges. This is a good way to get up close and personal with one of the small wasps that parasitize mason bees.
 
Gently dry the cocoons (mould can be a killer for the bees too), by placing them on dry towels and rolling the cocoons around to remove moisture.
 
Place the cocoons into a paper bag or cardboard box, such as a Jello container. Place it in the refrigerator or an unheated room until conditions are right in the spring for release.
 

Article compliments of Brian Campbell, Certified Bee Master.
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Comments
Alas- It is now mid August in the Gulf Islands. Is it too late to usefully provide new 'apartments' for Mason bees?
Posted by: Michael  
We are having a very wet and windy winter in Port Alberni - is it too early to put out cocoons?
Posted by: Libbie  
Hmmm... We bought a mason bee house and mason bees from WCS last year. Upon inspection through the summer, I did not see what looked like mason bees around the house, though the cocoons were hatched and none were left in the vile. I assumed there were no mason bees. This year, I was going to get some more, wash our mason bee house and start again, but I see some of the holes are mudded up. How do I tell what is inside and if they are mason bees? Because I did not clean the cocoons in the fall/winter, do I just leave them now? or try again? Throw everything inside out and start new? Thank you Mark & Brian!
Posted by: Angela