Orange-vented Mason Bee - Osmia leaiana

Description

10mm females, 6mm males. As with all Osmia species, it has a large box-shaped head (similar in size to the thorax). Females have a dense orange pollen brush under the abdomen. Males lack the pollen brush and are generally dark, often metallic green, with ginger hairs. Eyes are black. The tip of the abdomen is smooth (except for the central indent).

Similar Species

The males of O. leaiana and O. caerulescens are very similar. However O. caerulescens males have green eyes (when alive) but these are black in O. leaiana. Also, the tip of tergite 6 is crenulated in caerulescens but smooth in leaiana (except for the central indent).

Identification difficulty

Females , Males

Recording advice

Records should include a photo, or set of photos, showing the key characters. We will accept records identified by a recognised local or national expert, or that have been identified via the BWARS’ Facebook noting the name of the person/organisation identifying the record (e.g. ‘Stuart Roberts, BWARS Facebook’).

Habitat

It uses a wide range of habitats, especially sites with plentiful thistles and knapweeds. It can be frequent in gardens and is one of the species that like to exploit bee hotels.

When to see it

Between May and August.

Life History

Nests in cavities in dead wood, walls or cliffs. Adults collect pollen exclusively from Asteraceae.

UK Status

Restricted to England and Wales. It is less frequently found than O. caerulescens, but occurs in similar habitats.

VC55 Status

Status in Leicestershire and Rutland not known.

Leicestershire & Rutland Map

MAP KEY:

Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2025+ | 2020-2024 | pre-2020

UK Map

Species profile

Common names
Orange-vented Mason Bee
Species group:
Bees, Wasps, Ants
Kingdom:
Animalia
Order:
Hymenoptera
Family:
Megachilidae
Records on NatureSpot:
35
First record:
12/07/2013 (Helen Ikin;Steve Woodward)
Last record:
23/07/2024 (Nicholls, David)

Total records by month

% of records within its species group

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