Osmia caerulescens

Osmia caerulescens

profile iconSolitary bee on scabious, Sandy, Bedfordshire (7615501134)
by Orangeaurochs (CC BY 2.0)
1 of 3
A close up of a Blue Mason Bee Osmia Caerulescens on a flower
profile iconSolitary bee on scabious, Sandy, Bedfordshire (7615501134)
by Orangeaurochs (CC BY 2.0)
1 of 3
The blue mason bee, not to be confused with the blue orchard bee, is a small species of solitary bee. Like many mason bees, this species will use mud and chewed up petals and leaves to construct the walls of the nest. These tiny bees fall just under 1cm in length and are an iridescent blue under sunlight, displaying tones of blues, greens and turquoise when the light reflects from them. These small bees enjoy nectar from the smaller flowers, such as lavender, catmint and snapdragons, to name a few.
Free download for your phone or tablet
Download on the App StoreGet it on Google Play

Traits

Blue mason bees are attractive bees.
They may take bites from the petals of some flowers.

Appearance

Adults: Osmia caerulescens are below 1cm, so it can be challenging to spot if you're not looking out for them. They can appear black but when the light shines on them, appear an iridescent blue, sometimes showing tones of greens and blues under sunlight. If you can get close enough, you may be able to spot the white leg-hairs. The pollen-collecting hairs beneath the abdomen are black.

Symptoms

These bees may bite into flower petals, however, in most cases they won't cause significant damage.

Activity

Diurnal

Personality

Order

Hymenoptera

Family

Megachilidae

Metamorphosis

Complete

Distribution

These bees are steadily distributed throughout the UK, although not too abundant. They're also found in South East Asia and Northern America.

Biological treatment

These bees are effective pollinators, bringing benefits to gardens. Encourage these bees to your garden by planting bee-friendly flowers, and they especially like plants that produce fruit crops!

Chemical treatment

It's not advised to treat gardens with bees. Plants which are in flower should not be sprayed if possible. Bees can be affected even if they weren't intended to be.

Attracts this pest

These bees enjoy the nectar of short-petaled flowers.
Free download for your phone or tablet
Download on the App StoreGet it on Google Play

Knowledge and advice

Search our ever-growing knowledge base to find plants and information. Find out about pests and diseases you should be keeping an eye out for. Watch How to videos or follow step by step guides for tasks in the garden. Free download for your phone or tablet.
Download on the App StoreGet it on Google Play