Last year I started raising orchard mason bees (Osmia lignaria), which are cute little solitary bees that live in holes in masonry or wood, or in the case of my bees, in paper straws made specially for them. At least, in theory mine live in straws.
Keeping mason bees is a much simpler affair than keeping honey bees. Mostly it’s just providing nesting space (straws or reeds), mud (they use it as dividers between eggs), and pollen during their active period, which is in the spring. After they’ve laid all their eggs or their wings are too tattered to fly, which is around when most fruit trees stop flowering, the adults die, and you put the straws which are now full of eggs and larva somewhere warm and protected from birds, beetles, and mice. Then in the fall, you pop the straws in a refrigerator until a few weeks before the fruit trees begin to bloom in the spring. In the fall, you’d generally also want to open up some of the straws and check for pests, which only takes a few minutes.
Since last year was my first year raising mason bees, I slightly screwed up this process, and when I put the straws inside in mid-summer, I put them in the basement, but I should have put them somewhere warmer. This Spring, I put some of the tubes out in March, and some in April. Until today, I though I may have killed them all, because I had only seen a single bee hanging out around the bee house, and I should have at least 60 cocoons. Usually in the spring, the males emerge first, and hang around the nesting holes until the females emerge, so they can mate with them. Then the females go out and gather pollen and mud, lay eggs on top of piles of pollen, and seal off the eggs with a wall of mud, and then repeat the process until they die a month or two later.
Because I thought I had killed off all my orchard mason bees, and it’s too late to order more this year, I decided to try summer mason bees, Osmia californica. Californica bees are very similar to orchard mason bees, except they emerge later in the year, they use chewed up leaves instead of mud to separate their eggs, and they prefer aster-type flowers. I got my little carton of 20 californica bee cocoons in the mail today from Crown Bees, and I was surprised when I opened it that it smelled distinctly like flowers.
There was also one little bee that had emerged from his cocoon during shipping that was crawling around in the box, so I carefully slotted the carton into the mason bee house I made last year, and got to watch him crawl out to the roof of the house to sun himself. I started taking photos of him crawling around covered in the pollen that had rubbed off on him as he made his way through the other cocoons, and it didn’t take long to notice that there were some orchard mason bees also flying around near me. I couldn’t figure out why they seemed to be bouncing off the wall next to the bee house, instead of flying into it, so I stood back a few feet in case I was in the way. This is when I realized that they weren’t accidentally missing the bee house- they’re heading for old nail holes in the wall instead. It makes me wonder if the others are either just late to emerge, or are perhaps nesting in my wooden shingles. I’m not sure why they’re shunning my paper tubes, but I’m glad to know they’re not all dead.