Red Mason Bee Sealing a Nest

This year I have a bee hotel attached to the house which provides somewhere for solitary bees to nest. The most commonly seen garden solitary bee is the red mason bee (Osmia bicornis) which finds cavities, such as in walls or canes in which to lay its eggs. It adds some pollen for food and seals up the cell with mud.

Yesterday I managed to catch a female red mason bee sealing off one of the tubes in the nest box and took some photos. They are not amazing photos, my main excuses being failing light and rubbish photography skills; I was also watering the garden and getting some washing in at the same time, etc etc. A selection of photos in chronological order are below, with the time taken in the caption.

In the first photo, you can see the female deep inside the tube.


Twenty minutes later the start of a wall is in place and the bee has gone off to get some more mud.


A few minutes later and she’s back constructing the wall.


Again she’s off, and there is now a complete ring.


Three minutes later and the ring is closing in.


The female is back with more mud.


Now the hole is clearly too small for her to get in or out.


More work…


…and the hole is sealed!


The bee continues to add more mud for a better seal.


The last photo is from over an hour later and shows the cap jutting out from the wall, not entirely neatly.


There are now six holes filled up in the bee hotel. I understand that each of the holes will have a number of cells, one in front of the other. Next spring, the small males, whose eggs are laid near the front, will hatch first, followed shortly by the larger females. There are hundreds of sorts of solitary bee in the UK, although only the larger ones will use the bee hotel. I saw some leaf-cutter bees, such as the one below, last year.

Leaf-cutter bee cutting a leaf

They use mashed-up leaf pulp instead of mud to do much the same thing, so I hope they might pop by too.