#3612 · 🐝 bees, wasps & ants
Blue Mason Bee
🇳🇱 Blauwe metselbij ·Osmia caerulescens
7 photos from iNaturalist (Creative Commons) · credits & licences
what is it?
Osmia caerulescens , the blue mason bee , is a species of solitary bee from the family Megachilidae. It has a Holarctic distribution extending into the Indomalayan region, although its presence in the Nearctic may be due to human assisted introduction.
base stats
Bars compare against all animals on log scales: up to 300,000 Dutch and 600,000 worldwide sightings (the most-seen species), 150 t (blue whale), 30 m and 400 years (Greenland shark).
fun facts
- Spotted 28 times in the Netherlands on iNaturalist.
- 2,543 observations worldwide on iNaturalist.
- Scientifically named in 1758 (268 years ago).
fact sheet
- English
- Blue Mason Bee
- Nederlands
- Blauwe metselbij
- scientific name
- Osmia caerulescens
- class
- Insecta
- order
- Hymenoptera
- family
- Megachilidae
- in NL
- native
- sightings in NL
- 28
- sightings in Europe
- 837
- sightings worldwide
- 2,543
- GBIF records in NL
- 4,362
- weight
- —
- length
- —
- lifespan
- —
- named
- 1758
relatives· Megachilidae
#3510 📷 8Red Mason Bee
🇳🇱 Rosse metselbij
Osmia bicornis
👀 595 in NL
#3518 📷 10European Orchard Bee
🇳🇱 Gehoornde metselbij
Osmia cornuta
👀 364 in NL
#3539 📷 10European Woolcarder Bee
🇳🇱 Grote wolbij
Anthidium manicatum
👀 141 in NL
#3586 📷 10Banded Mud Bee
🇳🇱 Lathyrusbij
Megachile ericetorum
👀 39 in NL
#3605 📷 10Large-headed Armoured-Resin bee
🇳🇱 Tronkenbij
Heriades truncorum
👀 33 in NL
#3636 📷 8Florentine Woolcarder Bee
🇳🇱 Geelschouderwolbij
Anthidium florentinum
🌍 6.5k seen
Sources: iNaturalist taxon 199124, Wikidata Q2388784, GBIF 5039096, Wikipedia (EN), Wikipedia (NL). Intro text from Wikipedia (CC BY-SA 4.0).Updated 2026-10-24.