Mason Bees Nesting in the Bug Box

bug box on allotment shed

We have some exciting news to share! Mason bees (Osmia rufa) are making nests inside the bamboo cane bug box, sited on the allotment shed. Mason bees are solitary and do not form colonies or produce honey. The Mason bee gets it name due to using mud in building nest compartments, rather like a stone mason constructing a house. After mating, males die and females begin collecting pollen and nectar to build nests. After laying her eggs (males at the front and females at the back), the female seals the entrance to the tubular nest using mud. Mason bees may nest inside reeds or holes in wood made by wood-boring insects, some British species make their nests in empty snail shells. Luckily for us, 3-4 females have chosen to use our bug box.

If you look closely, you may just be able to see the mud-sealed entrance to one of the nests
If you look closely, you may be able to see a nest being built with mud. The tubes being used are yet to be sealed with a ‘mud plug’ which indicates a completed nest.

mason bee

The bug box is in full sun, sited approximately 5′ 8″ high, this is the first time the box has been used by bees. The bees were very calm considering we were about, using the shed and nearby area as we usually would. Mason bees are usually non-aggressive and will only sting if they are really threatened, ie being held between fingers. They would much rather get on with the job of building a nest rather than defending it.


We’re thrilled to be able to watch the bees, they’re brilliant little pollinators and very welcome on our plot. Plot 4 is certainly living up to its name – The Little Haven.

15 thoughts on “Mason Bees Nesting in the Bug Box

  1. I’ve got some bees in my allotment shed; I’m not sure if they’re Mason bees, but they could be I think.


  2. How wonderful.bees are threatened all over the world and people don’t understand that without them we have no pollination,no fruit no vegetables! We have a Mud dauber wasp it also is solitary,uses wet mud from the dam to build its tube nests for it’s eggs,it also will not sting unless provoked it lays the eggs paralyses spiders and puts them in the tubes.It is quite large and has big dangly legs and they have their tubes all over our house under the verandah..and because our house is made from reclaimed brick they are well disguised.I must put some picks up for you :)


  3. This looks like a great idea! We get a lot of native stingless bees in Australia, would be great to get a colony nesting in the middle of the veg patch! The allotment is looking great!


  4. we have 7 mason bees [I think] in our bug box and they have sealed the entrance with pieces of leaf, have they laid eggs inside and if so when do they hatch?


  5. Hi Terry, well done with attracting solitary bees, they’re brilliant pollinators! From your description, it sounds as if leaf cutter bees rather than mason bees (who choose to seal their nests with mud) have made nests in your bug box. The female(s) will indeed lay eggs, the bees should emerge late spring to early summer, all being well.


  6. I think my bug box has mason bees and there must be around 30 tubes blocked off by mud. do I just leave it alone for the new bees to emerge? and when will they hatch?


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