Did you know, that only 30% of Australia’s native bees nest in pre-existing cavities, such as bee hotels. The other 70% nest in the ground. As she digs a vertical burrow, the female bee mostly uses her mandibles to move soil up and behind her body. Once an appropriate amount of soil has gathered behind her, the bee pushes the load up and out of the burrow, using sonication of her body to assist in the excavation.
Most ground nesting, native bees range from 5mm to 13mm in length. Some dig relatively shallow burrows, with multiple corridors branching off from the main tunnel. Brood cells are constructed at the end of each corridor. Others, like some Ctenocolletes species, excavate burrows as deep as 3 metres! That’s a lot of work for a little bee.
So, it’s important that we keep these little diggers in mind when we go out to the garden with our shovels. Or, more commonly, with our wheelbarrow full of mulch. Just imagine how hard it is to dig through all that bark chip when you’re only 5mm long!
Try to dedicate an area in the garden where the mulch is sparce or absent. This may encourage your local little diggers to come and make a home in your space. And don’t forget… plant lots and lots of native flowering plants!