Invertebrates
Red Mason Bee
Osmia bicornis
On an April morning in an orchard, a red mason bee backs out of a hole in an old wall, her belly dusted yellow with apple pollen, and flies back to build another mud-walled cell.
Overview
The red mason bee, Osmia bicornis, is a Least Concern solitary bee found across Europe, North Africa, and western Asia. Its mud-walled nests, belly-brush pollen carrying, and value as an orchard pollinator make it one of the most useful and gentle wild bees in gardens.
A solitary bee that works orchards
Unlike honeybees, the red mason bee has no hive or queen, and every female works alone to fill her nest with pollen and eggs.
Status
Least Concern, widespread and common.
Red Mason Bee: common questions
Does the red mason bee live in a colony?
No, it is a solitary bee, and each female builds and provisions her own nest.
Why is it called a mason bee?
It divides its nest tunnel into cells with walls of mud, like a mason building with mortar.
Why do gardeners value the red mason bee?
It is a very effective pollinator of apple, pear, and other fruit blossom, and readily uses bee hotels.
When can you see red mason bees?
They are on the wing from March to June, with males emerging a few days before females.