Gold-fringed Mason Bee

Fast Facts

Latin name: Osmia aurulenta

Notable feature: Broad head and gold "fringes" on abdomen

Conservation Status: Least Concern

Where in the UK: Nationally Scarce but locally common in many coastal and inland localities in southern England. Apparently exclusively coastal in Wales, north-west England, south-west Scotland and Ireland.

Golden-fringed Mason Bee (Osmia aurulenta) © Vlad Proklov


The Gold-fringed Mason Bee (Osmia aurulenta) is a native, medium-sized, solitary bee that can be found predominantly in coastal localities; it can also be found inland – generally on calcareous soils (ie. grasslands, quarries, chalk woodlands).

Gold-fringed Mason Bee (Osmia aurulenta) © Liam Olds

Females are medium-sized with a bulbous head, brick-red hairs on their thorax and a brown abdomen fringed with orange-golden hairs (from which it gets its name).  Males are slightly smaller and duller in colour.

As with many solitary bees the Gold-fringed Mason Bee takes one whole year to pass through a complete life cycle and may only survive as adults for a few months. This isn’t long enough for them to raise their offspring to adulthood, so the young bees have to fend for themselves, hence the term ‘solitary bee’.

Following mating, females construct a nest containing a small number of cells in which she’ll lay an egg and leave a ball of food; made by mixing pollen and nectar. Once complete, she’ll then close the entire nest.  Adult bees will then die as they have completed their job. The larvae survive the winter, eating the food supply that’s been left for them in their own chamber. Emerging the following spring as adults when the cycle begins again.

    • Size:  Between 8-10mm in length (males are slightly smaller than females)
    • Life span:  Annual life cycle; adults are on the wing between April-August, typically peaking between May and July.
    • Diet: Females collect nectar and pollen from a variety of plants including Bird’s-foot Trefoil, vetches, thistles & Black Medick
    • Reproduction: Females of this species commonly build their nests in medium-sized to large empty snail shells.  Shells will ordinarily contain 1-4 cells with the dividing walls of cells made up of chewed leaf pieces
    • When to see:  Adults are on the wing between April-August, typically peaking between May and July.
    • Population Trend:  Unknown
    • Threats: Loss of habitat and food sources, as a result of agricultural intensification, urbanisation and scrub encroachment.
    • Fun Fact:  The Gold-fringed Mason Bee commonly build their nests in empty snail shells

How you can help: 

Buglife is working to increase awareness of invertebrates and the Gold-fringed Mason Bee through specific projects, including Natur Am Byth and B-Lines, but we need your help!

Buglife B-Lines are an imaginative and beautiful solution to the problem of the loss of flowers and pollinators. B-Lines are a series of ‘insect pathways’ running through our countryside and towns, along which we are restoring and creating a series of wildflower-rich habitat stepping stones. Linking existing wildlife areas together, creating a network, like a railway, that will weave across the UK landscape.  More information about B-Lines and how you can help pollinators can be found on our B-Lines & Pollinator Projects pages.

Join a recording scheme and log your finds – send any records/sightings to BWARS or download the iRecord app and get recording!

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