Harvesting Mason Bee Cocoons

Last weekend, I harvested my mason bee cocoons. I bought 10 cocoons (6 male and 4 female) last winter and refrigerated them until March. Then I put them out in an assortment of cardboard tubes and reeds in a little house. They woke up in the later part of March and were busy until around mid May. Since I harvested more than 160 healthy cocoons, I'm sure that quite a few native mason bees found my house and decided to lay their eggs there. I have a great location for mason bees (Blue Orchard Bees, or BOBs), since I have my little stream where they can get the mud needed to separate the egg chambers.

Here are photos I took during the harvest process. It was a little more difficult than I expected to get the tubes open. The reeds are much easier, so I went to Crown Bees in Woodinville and exchanged about 120 of my excess bees for a bunch more reeds for the spring.

It took me about 90 minutes to harvest the cocoons. This was my first time, so I think it will take less than half the time next year.

This photo shows the assortment of tubes I used and the first few cocoons I harvested:

 This shows some of the opened cardboard tubes:

 This is an opened reed. They are quite easy to open up. You can see the cocoons separated by plugs of mud. The black specks are bee feces.
The orange "dust" is pollen mite feces, which I found in a few of the tubes/reeds. I discarded the orange dust and the cocoons that were next to it.

 Here are my harvested cocoons. I brushed off most of the black specks (feces), but it doesn't hurt to leave some, so I didn't bother with any unnecessary work.

I kept about 30 cocoons and took the rest to Crown Bees for them to distribute to others who want to raise mason bees. They are working on getting more farmers (such as almond and cherry growers) to use bees as an additional type of bee.

The bees I kept are stored in the refrigerator until March. I put them in a little yogurt container, which rests in a larger container with some water in the bottom so they won't get dehydrated in the refrigerator. Then a poked holes in the plastic lid of the container, so they will get air. A no-cost way to safely store the bees while hey hibernate.

Harvesting bees will increase the numbers of healthy bees that survive.