Harvesting Mason Bee Cocoons for 2015

Harvesting Cocoons for 2015

I was very pleased with the number of cocoons my industrious mason bees created this year.   I started out with 17 viable mason bee cocoons the first year.  From those original 17 mason bees I got 35 cocoons for the next season.  From those thirty five bees I got 150 cocoons this year!  That’s almost 7 times more cocoons in just two years!  That definitely will require another mason been house on the side of my shed next year.

Cleaning out the mason bee houses this week revealed some interesting things.  I never did plug up the hole in the little attic so a good dozen wasps were still in there when I opened up the backside of the house.  Since it’s been so cold outside they were very sluggish, and a few were dead, so it was easy to scrape them out without risking any attack.  And of course I took the opportunity to try and get some close up micro shots with my new camera.

The most cocoons deposited in one tube were nine.  The least amount were three.   All of them looked healthy.   I was very disappointed, however, with the development of the cocoons in the other mason bee house.  Those tubes were not protected by an outer tube, so they didn’t do so well and were moist and moldy.  Some of them were infested with tiny flea looking creatures and larva that I don’t think were mason bee larva.  Now I know not to place unprotected paper tubes in the holes.  I’ll need to drill the holes bigger for next year so that they will accommodate the outer tube as well as the black plugs at the back end to prevent the intrusion of those pesky parasites.

I wish I knew what those larva were crawling around in the tubes.  Maybe they were wasp larva.  Considering that the healthy mason bee cocoons are ready for winter, and I opened the one cocoon that revealed a fully developed mason bee, I highly doubt that those larva crawling around were mason bees.

Different Cleaning Methods

Since I had so many cocoons this year, it wasn’t so practical to clean each one with a Q-tip like I did last year, so I used river sand this time.   Using a strainer, I filtered out the finest particles of sand into a bowl.  With a Q-tip I gently stirred the cocoons around in the sand.  I then placed the cocoons in the strainer and kept pouring the sand over them while shaking the strainer.  It didn’t get all the mud & poop off the cocoons, but I think it did a fairly good job.  Hopefully any mites were shed as well. There were still some cocoons with the mud cap stubbornly attached to them, so those I just picked off.

There are other methods that can be used to clean cocoons.  One method involves washing the mason bee cocoons in a bleach and water solution.  That sounds a bit toxic and harsh, but apparently the cocoons are tough enough that it doesn’t hurt them.  The bleach solution doesn’t kill the mites either, but it’s supposed to do a good job of cleaning off the dirt and poop.

For the bleach and water method you get a bowl of cold water and add a small amount of bleach, about a ¼ cup to 5 cups of water.  That should be about a 5% solution, right?  Place the cocoons in the bleach water for about 3 – 5 minutes and stir them around.  Remove the cocoons and rinse them thoroughly with fresh cold water.  You absolutely do not want to use warm water since you don’t want the larva to awaken and think it’s time to emerge.   Lightly pat the cocoons dry with a paper towel.   Do not store them in the refrigerator wet.   After they’re dry, maybe a few minutes, put them in the fridge.  You don’t want the cocoons to warm up to room’s temperature.

This is my third year with the mason bees, and the more I learn about mason bees the more interesting they become.  Not only is it fun to house, clean and harvest them for the next season, I am just thoroughly impressed with these little guys.  They are incredibly industrious, and knowing how much greater they pollinate than honey bees, it makes it all the more important to give them a helping hand by creating a hospitable and healthy habitat for them.

As much as I love the mason bees, I still plan to get some honey bee hives, and this will probably be the year for that.  I’ve decided to allow my vegetable beds to remain fallow this next season as I work on building up the nutrients and minerals in my soil, so hopefully that will free me up to dabble more in my other hobbies and projects.    One can always hope!



This was a good article and nice website. The Important of harvesting mason bees cocoons:



Crown Bees puts out a newsletter almost monthly that teaches about Mason Bees and takes you step by step through the stages of care.   I’d highly recommend getting signed up if you have mason bees.  The following link brings you to their page where you can get questions answered for each stage of care:



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