At the end of my last post I asked if anyone thought Colletes bees might nest in bee hotels. The idea seemed improbable as they are called mining bees because they are subterranean nesters. However, I knew Colletes bees lined their underground cells with a waterproof cellophane-like substance.
In August I noticed that one of the holes in the bee hotel had been plugged and the surface had a glassy, shiny appearance. I was not able to take a better photograph as the substance was reflective.
Just under the hole a thin membrane, like a cellophane paper, was adhering to the rough wood.
I was encouraged by Susan (http://daysontheclaise.blogspot.fr/) to enquire on a forum. I was very reticent as I have never asked on a bee forum before so I posed my query on apoidea-gallica.
I received a quick response with a link to a photograph of another shiny plugged hole on Flikr and the suggestions that it could have been filled by a bee in the Genus Hylaeus.
My “Bees of Surrey” by David Baldock tells me that Hylaeus “nest mainly in dead stems (especially brambles) but also in crevices such as holes in wood, stones or walls. The cells are made in a line and are waterproofed by a cellophane-like material.) This seems a likely explanation for my mystery plug.
In addition, I had a photograph of an unidentified black bee on my Astrantia in September.
The photographs are not good enough to positively identify the bee but I’ve learnt a lot from the shiny plug in the bee hotel and I am going to be on the lookout for Hylaeus bees this summer.