Less Known Pollinators–Mason Bees

Honey bees have a reputation of being great pollinators, but a few years ago our neighbor introduced us to Mason bees as being even better pollinators for early blooming fruits trees such as apples, plums, peaches, nectarines etc. and pears, especially Asian pears because they do bloom the earliest in my garden. Mason bees emerge early spring while honey bees emerge in the warmer later spring weather. Our neighbor was kind enough to give us a few paper straws and told us to drill 5/16 in holes in a wood block then insert the straws into the holes and wait for Mason bees to take residents in them… The blocks were hanged on the fruit trees as he did, but they were not very successful attracting bees that year for some reason. After we moved the blocks under the south facing patio, the Mason bees are lot happier! We have to add new blocks every year since then because the population is growing. It’s very entertaining to watch them busy going back and forth building their nest cavities which are called brood cells inside those block holes. When you use paper straws liners, you’ll need to change them every year, but ours are just plain wood blocks, they seem don’t mind at all to use them year after year, even the cedar block which is not recommended because the odor, they didn’t seem mind at all. Maybe our blocks are well seasoned, 😉

This is one of the original blocks we had, and they are still using it… Spring time, yay!

One of the newer blocks. Mason bees first put the pollen into the cells to make a pollen loaf which will take a female bees about 25 or more trips, then they come out and back into the cell to lay their eggs, after that they’ll seal off that cell with mud clay and repeat the process again until the hole is completely filled! The holes are 4 to 6 inches deep, wondering how do they construct those brood cells in each hole…🤔

Well wonder no more! By accident we discovered their Secrets.

Apparently there were so many of them this spring and they literally ran out the holes in the blocks to build their nests in, so they started to build them on the under side of a plant tray, I find that out by removing that tray… Poor bees, so much work was wasted cuz careless of me, I am so sorry.😒

Huge pollen loaf made of pollen and nectar for a little tiny egg.

Mason bees are called mason bees because, in a sense, they do masonry work. Pretty impressive construction they did indeed! Each brood cell is sealed off with mud clay. This female bee had made 8 brood cells which is more than the normal of 5 to 6! And each female has about 15 to 20 eggs in her life time, plus they only live about 25 days which explains why they are always in such a frantic stage when you see them…have to get the work done in time I suppose!

As bee populations grow, we add one or two more blocks each year. All of the holes had been filled this spring, and obviously some insects or birds had been getting into the holes. Also as mason bees are building their brood cells there are always those Houdini flies ( Cacoxenus indagator, kind of fruit flies) flying around the holes. They are kleptparasites meaning parasitism by theft! They do not attack mason bees directly, but lay their eggs on the pollen loafs meant for the mason bee young. The Houdini fly maggots then emerge and consume the food before the mason bee larvae, which causes them to starve. We definitely get rid of those nasty flies whenever we see them hovering around the nesting boxes.

This block box was made by stacking pieces of wood board on top of each other, the holes are square instead of round. What we have noticed was that the bees would first put the mud clay in to the holes to fill up the 4 corners in order to change the configuration of the square into the round holes, then they would started to build up the pollen loafs and eventually lay their eggs. Pretty ingenious wouldn’t you say?

We have also noticed that they were building the nest in the holes of a pair of my old shears’ handle bars (see the video below). People order mason bees online for their gardens, but if you just make yourselves a block or two, you will for sure to have them around to pollinate your garden delights.

Here is an interesting fact, in order for pollination to occur, orchards need less mason bees per acre than they would honeybees. Mason bees have a 95% pollination rate, where honeybees have a 5% pollination rate. Guess Honey they produce will make for their low pollination rate!😉

By the way, “Despite having a stinger, female mason bees are not aggressive and rarely sting, even when handled. The sting is also much less painful than that of a honey bee. As a result, beekeepers do not need any special protective equipment when working with mason bees. Male mason bees do not have a stinger! “

Here are a few video clips to see those amazing bees in action…

https://photos.app.goo.gl/6K6qxgo5ACsBYnhn8 (seal off the hole with clay)

https://photos.app.goo.gl/DGcnK5xfysPS9dFZ7 (nest in the handle bars)

https://photos.app.goo.gl/4EbCtQ5n5ttoLgKA9 (house cleaning before moving in)

https://photos.app.goo.gl/TjmUd9dtNk5Vjx8MA (house cleaning 2)

https://photos.app.goo.gl/omvB1N12u1w3LJcu9(oops, wrong nest)

https://photos.app.goo.gl/kXvRWFxaw4EoT8K87 (seal off the hole 2)

Here is a very interesting article about mason bees’ life cycle if you’d like to know more about those beneficial bees!

https://crownbees.com/pages/mason-bee-life-cycle

Less Known Pollinators–Mason Bees

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