Harvesting Mason Bee Cocoons


Back in early December I cleaned out our mason bee tubes and harvested the cocoons for use in the spring. This is the first year I have harvested cocoons, it was pretty interesting!


I started by collecting all the tubes that had some kind of mud in them and setting aside the empty tubes for use again next year. I then unraveled them one by one to figure out what was inside. We didn’t have a crazy amount of success as a number of the tubes were actually empty or filled with red mites, but I did manage to collect a few cocoons. I also ended up with two types of bee, Osmia lignaria, the more common Orchard Mason Bee, as well as a bunch of Osmia californica, a different type of mason bee that comes out later in the season. We left out house out into June/July, so that is likely why we had so many of the californica bees.

The first image below shows the lignaria cocoons between the mud chamber plugs and a bunch of black bee poop.


This image shows the cocoons I suspect are californica cocoons, as you can see they have more pollen left behind and also some small red mites.


I rinsed the cocoons under cool water to rid them of dirt and mites, then soaked them for a minute in a bowl of cold water with about 5% organic bleach content to kill bacteria. Apparently the bleach does not permeate the cocoon shells so the bees inside are unharmed. I’ve also read you can clean the cocoons with sand, but I went with the bleach method. Here are the two different types of cocoons I harvested:


01_05_2015_10 01_05_2015_08

We didn’t get that many, but we had a late start to the season so this year we will put them out sooner. To keep the cocoons dormant until the spring first I dried them gently, then placed them into a toilet roll tube inside a couple of jars with breathable tops. I then put the jars in the fridge where they will stay hibernating until the spring when I put them outside with the house.

Did anyone else do mason bees last year? Do you want to try them in the year ahead?



  1. Thanks for sharing — that’s so cool!
    I would love to have bees on day, hopefully in just another year or two! What made you choose mason bees?

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  3. Thanks for pointing out the californica bees! I cleaned the tubes today from my property on the Southern Oregon coast and was baffled by the variety of cocoons. I definitely had more californica cocoons than anything else. Now if I can figure out what the little smooth reddish cocoons are, I’ll be set. πŸ™‚

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