mason bees wild bees and native bees

Make room for mason bees

My first shipment of orchard mason bees arrived in shiny little tubes that look like drinking straws, packed in a box that weighs next to nothing. So why am I messing with mason bees in the midst of a million honey bees?

The answer is partly because they’re native—I encourage native species whenever I can—and partly because they’re fun. Then, too, I have pear trees; honey bees like pear nectar as much as Bush-the-elder likes broccoli. Honey bees are amazingly polylectic, which means they collect nectar from a wide variety of plants. They have their favorites, however, and pear isn’t one of them. Pear nectar is generally lower in sugars than other orchard nectars so, unless pickings are slim, they will pretty much ignore it.

There are several species of mason bees, but the ones native to the coastal Pacific Northwest are Osmia lignaria. They are in the same order (Hymenoptera) as honey bees, but in a different family (Megachilidae). Compared to honey bees, mason bees are extremely efficient pollinators. Just two or three mason bees can pollinate the equivalent of a mature apple tree in one season.

Like most of the native bees, mason bees are solitary. After the female is fertilized in spring, she raises the next generation by herself. She searches out comfortable digs—usually a hole or a hollow reed—and collects a pile of provisions (nectar and pollen) which she deposits at the far end. On top of this she lays an egg and then walls off the compartment with mud—hence the name “mason” bee. She continues this process until the hole is filled and then begins another.

The eggs she lays go through complete metamorphosis like a honey bee except, instead of being fed by a solicitous hoard of nurses, the developing larva has only her personal supply of grub. I say “her” although the last egg to be laid—the one nearest the opening—is a “him.” Like a LIFO system of inventory (last in, first out) the male bee is the first to hatch. Biologists call this phenomenon “protandry.” Protandry assures that the males will be fully mature and ready for the females when they emerge. (I know what you’re thinking but, no, they are not incestuous. Other brood from other females is hatching at the same time.) Protandry occurs in many species. In salmon, for example, the males arrive at the spawning grounds first, then rest (have a beer) and wait for the females to arrive. The system works.

Orchard mason bees have lots of people-friendly attributes. Since they have no large stores of honey or masses of brood to protect, they are relatively docile. They will sting if stepped on or grabbed, but they don’t fly into large hairy mammals to resolve territory issues. Unlike carpenter bees, masons use existing holes and never employ awls or augers on your siding or lawn furniture. Also, since they don’t live in large colonies, they don’t swarm onto your neighbor’s swing set or leave fecal trails on their BMWs. Furthermore, unlike honey bees, they don’t stray very far from home—put them in your orchard and they’ll probably stay there.

Lastly, mason bee houses are much cuter and smaller (and did I mention lighter?) than honey bee houses. Why not give them a try?



  • Yesterday was a flying day, the second in a row, but there was no flying out of the nuc we’re babysitting. My husband suggested we take a break from beekeeping this year, and oddly enough I agreed that it was a good idea. And then he suggested mason bees, which I thought was a GREAT idea. I went straight to the computer and, I’m not sure I got my order in on time, but we’re giving BOB (Blue Orchard Bees) a try. Glad you’re suite includes mason bee stuff, too, ’cause you can be sure I’ll be looking for advice. Thanks!

  • HB,

    Don’t go getting all discouraged on me! I’ll let you take a year off, then back to it for you.

    I think you will enjoy your blue orchard bees. They’re fun to watch and they start so early! They will give you some time to re-group before you start with honey bees again.

    • Coming up with good content seems easy for you, but I was mentally equating taking a break from the honeybees w/taking a break from my blog. One of these days, the boss IS going to catch me blogging instead of working.

      I just got the email confirmation that my mason bees are on the way so now I’m really playing with fire. I’ll have a whole ‘nother Backyard Bee Hive to blog about, at least until June. Then who knows… I don’t think we’d turn down a Silver Spoon.

      • HB,

        That’s funny, because I obsess over what to write about. It keeps me awake at night. Do you ever wonder why we blog, especially since it can be so distressing?

        One of the best parts, at least for me, is the little group of regulars who always comment. It’s kind of like having pen pals. Without them it would be like writing a letter and putting it in a bottle or a space capsule and wondering if anyone would ever read it.

        Anyway, I’m glad your mason bees are coming. I worry about bees–all bees. I don’t see how any at all survive with the way we treat our environment. Anyone who helps them out is doing a good and selfless thing.

  • Hi Rusty,
    My husband’s co-worker gave us a few straws of mason bee cocoons to try our hand at solitary bees. (We currently keep honeybees). The straws are currently in a box in our unheated garage (we live in W. Washington). I’m a bit confused after reading the internet’s “not-so-helpful” sites on Mason bees. Are we supposed to cut open the straws and put the cocoons in the fridge until spring? Or leave them in the straws and put them out when weather is consistently 50’s? Thought maybe you would know best in regards to how to treat them in this climate, since you are from this area.
    Thanks so much!!

    • Michele,

      First read my post, “When should I put my mason bees outside?.”

      The way you handle the straws is optional. Some people cut the straws open and store only cocoons, other people leave them in the straws and let them emerge directly. I’ve done it both ways and don’t see much difference in the results.

      I store my straws in my garden shed and don’t bother with the fridge. Last year, I forgot about them and they began to hatch in the shed. Once I opened the door, all was well. There is a lot of hype and nonsense surrounding mason bees, much of it pushed by people who want to sell you all kinds of stuff the bees don’t need. I frequently consult the USDA bee lab and some of the universities about mason bees and, so far, have been confirmed in my suspicions.

      As a rule of thumb, daytime temperatures should be in the 50s and there needs to be a food source for the bees nearby (open flowers). But there is flexibility. If you have fruit trees you want to pollinate, you can wait until they’re nearly ready to bloom before putting them out. But also remember that if they have been in cold storage, it may take a week or two for them to begin emerging. Males hatch first, but it’s the females you need for pollination.

      Regardless of other systems, mine works well. Last year I remember thinking, “I have 10 honey bee hives on the property, but you’d never know it. All we ever see is mason bees.” Honestly, they are everywhere.

      Just for the record, it is March 1 and mine are still in the shed. My pear trees don’t look anywhere near ready to bloom, so I’m holding back a bit on the masons.

  • Thank you, Rusty. I did notice the other post AFTER leaving my comment on this thread. Oops. However, I would have still asked the questions.
    I was wondering about “March 1st” from another post, and our fruit trees are also not even close to blooming, so good to know to just wait. And, that I don’t need to be enticed by all the stuff companies are selling, lol.

    Your reply was more helpful than my hours of internet searching. Looking forward to seeing the masons, not sure if I’ve ever noticed them before, just our honey bees.

  • I put my little guest houses out last year, have no idea what I’m doing, and one filled right away, but not the other. However, they are sealed with mud and I did not move them from the original location. We had our first really warm days last week, got up to 70 degrees; we have these teaser days every spring, and mason bees were swarming around the little houses. I have just left them alone assuming they know what they are doing. Now my question, will the bees just emerge on their own or do I need to do something. Doing something seems rather arrogant since they have managed forever without me. Do you have any idea why they would shun one house and not the other? I have mason bees living in my blower so not using it for the moment. I am just befuddled why they seem to like one location and not the other right next door.


    • Hi Jane,

      This is the “I think” answer rather than the “I know” answer! I have noticed this, too. I use cans filled with straws and notice that the bees will completely fill up one can before moving to the ones on either side of it. I think it has something to do with pheromones. They sense where other bees live and build close by. I think living together has something to do with safety, as in they are more easily able to fend off predators if they live in small groups. In short, I don’t worry about it.

      As for “doing something,” I fall on the laissez-faire side of the coin. I just let them do their own thing, just as they would do if they lived alone in a raspberry cane. Big producers end up needing to do a lot of cocoon cleaning, etc because large, single-species installations attract lots of parasites and predators. But for the homeowner with a few hundred mason bees, this is usually not a problem. Two years ago, I sent a number of inquiries to different researchers about this very question. They agreed that interference was not necessary unless you run a big operation.

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