C Beese

Mike Barkley wrote:My interest is honeybees BUT we have a lot of wild mason bees here. I watch them almost daily in warm weather. Seems they will bore into any type of wood. Trees, deck railings, loose lumber scraps, old furniture, stumps, etc. Not a significant problem as long as there is an alternative for them such as trees & bee condos.

Only the bigger carpenter bees in the Xylocopa genus have the lifespan and muscle power to drill into wood. Smaller carpenter bees in the Ceratina genus chew through pithy stems of raspberry canes. Our mason bees are only flying as adults for 4-6 weeks and that's not enough time to chew through wood. Xylocopa bees can only chew a 1/4" deep tunnel each day to give you an idea of how long it takes. So what you're seeing with the little blue mason bees is them finding an existing hole left behind by something else, probably a grub of some kind. Standing dead trees are perfect but not always safe and I'm happy to see landscapers leaving behind as much standing as they can safely. Widely available bee condos and hotels are getting there but a lot of the designs out there are not great.

Hugo Morvan wrote:
I'm in France, and have to render a wall of the house, it's an old wall and over time different farmers have used different mixes to patch up the wall. I noticed the mason bees live in the wall (i saw their "doors"),and they have a strong preference for one of the render types. It is a very soft one, with hardly any lime but it consists mainly of silt and clay. So my plan is to scrape this favored render type out and keep it seperate in a bin ,until after i rendered the wall with a traditional mix, then i want to make some wooden frames here and there on the wall and fill it up with the mason bees preferred render. I wonder if you have any idea if this will work, because i believe they have a completely different worldview and extra senses we can not even begin to imagine then we do, and the mason bees might not like the idea i have, or worse, that it will make it easier for predators.
Any help welcome.

I admit that I'm not sure if the European mason bees behave in the same way as our Osmia lignaria do, but from what I've heard they do have the same lifecycle and habits. Mason bees are fairly small and have a short adult lifespan flying - only about 4-6 weeks. That's not a long time to spend drilling holes in walls and they are opportunists that use old grub tunnels or holes made by something else. I don't know if your plan will work and it might be easier to just provide a nice mason bee house, properly made. Look for something with 8mm sized holes and is about 6" deep (sorry I don't know the # in cm).  I do know that mason bees prefer to gather moist mud that is just like pottery clay and what you've got is the perfect mud mix for bees. The mud is half the battle with raising mason bees!

r ranson wrote:

Would bamboo work if you made a new hotel each year?  It would be a bit more work than the ideas suggested above, but it might reduce the pest problem?  

My neighbours are big into native bees and they have some hotels that they clean out (and store the cocoons somehow I wasn't paying attention to but they say it prevents mites) but they also drill holes in several firewood logs.  At the end of the hatching season, they take those logs and move them back into the firewood pile hole side down, and drill new ones for this year's bees.

I'll explain how pests are spread with hole-nesting bees.

Chalkbrood is a fungal infection and pollen mites are microscopic mites, both are on flowers and are picked up, brought home to the nesting hole. Inside the nesting hole are a series of nesting chambers, all in a line. Usually the infection happens right in the middle, so the healthy adult bee has to walk through the fungal spores or pollen mites. Now all the chambers on the outside edge have fungus and mites inside them and they get spread to new flowers. Mason bees do not have the ability to clean out nesting holes.

The only way to reduce chalkbrood and pollen mites is by opening the nesting hole each year, taking out the healthy cocoons (we call this cocoon harvesting), and leaving the chalkbrood cadavers and pollen mite mass behind. With our reusable wooden trays you can brush away pollen mites and spot clean locations of chalkbrood with a mild bleach solution.

Bamboo is very hard to open and it behaves like drilled blocks of wood - no way to get the cocoons out easily.

What your friends are doing is one way to keep the pests down because at least the bees are using a fresh nesting hole. Another idea is to take our white paper Inserts and tuck them into each drilled hole or bamboo tube. Another problem with bamboo tubes is they are not cut properly and there is a node right at the open edge. Nesting tubes need to be 6" long so that female eggs are laid at the right ratio. I have a feeling that lots of people are going to get frustrated with their bamboo bee houses in a year or two.

We provided the information for The Honeybee Conservancy and nesting holes that can't be opened are not recommended (bamboo can't be opened). Just like any other creature, mason bees have their own pests and diseases and when we don't take care of the cocoons the pests can spread. Mason bees are not able to clean out chalkbrood (fungal infection) or pollen mites (they eat the pollen loaf before the bee larva can). If you don't have time to harvest cocoons you should provide fresh nesting holes each spring using the tips from our new blog post: https://crownbees.com/blog/movingday/


I'd suggest reading our website. We are mason bee raising experts and our advice is based on decades of experience.