I knew last year my mason bees laid many eggs, however I frequently saw wasps and other predators near their nest during the summer and autumn. I feared for their survival as many of the chambers were punctured by weather and other insects.
It seems like my fears were unfounded.
However, I did notice a serious problem. Upon closer inspection of the photo I took below, I saw hundreds of what appeared like mites tightly packed on to the bees.
This affected all my bees. So I decided to capture one bee, remove a mite and placed it under the microscope. This is where I picked off one mite.
And the mite itself under a light microscope.
I will try and sterilize the bee houses in the autumn as best I can, and hope that is sufficient. These Chaetodactylidae mites are really tough...
PS: On a lighter note, mason bees love just like we do.