Last year during the late summer I was surprised to see a new kind of bee using the bee boards I constructed. I placed these homes on different properties where the land owner was okay with it. And was happily surprised to see a whole new kind of bee using them. Honestly the first time I saw them from a distance I thought some large hornets were using my homes. I carefully walked up to them and saw they were indeed bees, though not a Leafcutter or Mason bee but instead a Giant Resin bee.
They are solitary bees just like the others that use these homes, but instead of leaves or mud they collect tree resin. They seem to be just as friendly as the Leafcutter Bees and the Mason Bees though a lot larger. Their wings drone as they fly by you and its pretty fun to watch them carrying in chunks of amber to form into homes for their larva. After the adult Resin bee queens left the area I took them bee boards to a safe location. And while harvesting my Mason bee and Leafcutter bees I decided to take a peak inside to see what is forming.
More information on Giant Resin Bees:
https://en.wikipedia.org/wiki/Megachile_sculpturalis
https://extension.umd.edu/resource/giant-resin-bee
https://bdj.pensoft.net/articles.php?id=6733
As I attempted to separate the bee boards I noticed that it required a lot of prying. Unlike the Mason bee homes that can be opened by hand, these Resin bee homes required me to use a screw driver and considerable force to open up the boards.
The resin that holds their homes together was amazingly strong though once open I could see the cells inside and the larva. They have yet to pupate, probably due to them starting their season much later than the Mason bees and Leafcutter bees. So it would take the resin bees many more months to cocoon over. Before opening these homes I attempted to research when to open and how to harvest their homes, but it would seem Resin bee husbandry is next to non existent.
So due to little information online about them I just took the chance and opened one of the boards. Now I know they need a lot longer to form.
I was surprised to see very little predator damage to the homes, usually pollen mites and tiny parasitic wasps are a concern for my Mason bees. Though it is possible the resin like material is much harder to penetrate than mud so maybe they are indeed safe from them. Also due the sticky nature of the resin I saw some wasps that did find a way in but appeared to get stuck in some of the resin. If this is the case I have no reason to open the homes, and will just let them spawn when ready.
Unfortunately the larva that were exposed will probably not make it. It looks as if I damaged their homes as I opened up the boards. Though I stopped at the first board when I saw this, so there are still six other boards probably with this many larva inside that are still intact.
Another observation was how they plugged the holes, it looks like mud is used at the end of the holes where you would see it from the outside. But a few inches in they appear to have wood chips, possibly re-enforced with resin. And then finally a heavy resin forms the cells between the larva.
One of the larva popped out when I was opening the boards, here is what is looks like. Its about the size of a cashew nut. Unlike the Mason bees that are barely any bigger than a couple grains of rice.
After I inspected the open Resin bee board I placed it back together the best I could and hoped the larva I exposed wont die. I got back to work harvesting my Mason bees, which now I have a few seasons of experience with.
I will do a follow up post soon with more pictures of my Mason bee harvest, showing what the mites look like that I clean out and a better look at their mud homes and pollen storage. Also I have some more pictures of the Leafcutter bee homes so I will show those off at a later date as well.
As for the remaining Resin bees, I will just let them form inside the bee boards and then come out naturally as well. I am planning on staggering the placement of my bee boards so the resin bees will have their own boards to populate. That way any pests that try to move into the earlier spawns of Mason bees can still be dealt with.
Previous posts from me about Resin Bees:
@solominer/resin-bees-making-use-of-old-carpenter-bee-homes
@solominer/the-kinds-of-solitary-bees-around-me