CRCritically Endangered

Fringe Horned Mason Bee

Osmia pilicornis

The Fringe Horned Mason Bee is a distinctive solitary bee species characterized by prominent horn-like projections on the male's antennae that are fringed with specialized hairs. This medium-sized mason bee constructs individual brood cells using mud and plant materials, typically nesting in cavities within dead wood or rock crevices.

01Classification

Taxonomy & Classification

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hymenoptera

Family

Megachilidae

Genus

Osmia

Fringe Horned Mason Bee belongs to the family Megachilidae, order Hymenoptera, within the Insecta class.

02Description

Species Profile

The Fringe Horned Mason Bee is a distinctive solitary bee species characterized by prominent horn-like projections on the male's antennae that are fringed with specialized hairs. This medium-sized mason bee constructs individual brood cells using mud and plant materials, typically nesting in cavities within dead wood or rock crevices. As a specialized pollinator, it plays a crucial role in maintaining plant diversity within its native ecosystems.

The Fringe Horned Mason Bee faces severe population declines primarily due to habitat loss and degradation of its specialized nesting sites in coastal areas. Agricultural intensification, urban development, and changes in land management practices have eliminated much of the species' required habitat, while climate change may be altering the availability of suitable nesting conditions and food plants.

Key Facts

IUCN StatusCritically Endangered (CR)
GroupInsects
03Habitat

Habitat & Distribution

The Fringe Horned Mason Bee inhabits mature deciduous and mixed woodlands with abundant dead standing timber and fallen logs that provide essential nesting cavities. It requires areas with diverse native wildflower meadows and woodland edges within close proximity to its nesting sites, particularly favoring locations with south-facing slopes that receive optimal sun exposure.

04Threats

Threats

!

IUCN Red List: Critically Endangered

The Fringe Horned Mason Bee faces severe population declines primarily due to habitat loss and degradation of its specialized nesting sites in coastal areas. Agricultural intensification, urban development, and changes in land management practices have eliminated much of the species' required habitat, while climate change may be altering the availability of suitable nesting conditions and food plants.

Agricultural intensification

HighOngoing

Habitat loss and fragmentation

HighOngoing

Urban development and coastal development

HighOngoing

Changes in land management practices

MediumOngoing

Climate change impacts on habitat suitability

MediumOngoing
07National Status

National vs Global Threat Status

How this species is assessed at the national level compared to its IUCN global status (CR).

CountryNational StatusGlobal StatusComparison
EULCLeast ConcernCRCritically EndangeredLower local risk

National Red List data sourced from the National Red List Project (nationalredlist.org, ZSL) and country-specific Red List authorities.

Community

Community Sightings

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07Sources

Sources & Attribution

How to Cite

IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS

GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org

National Red Lists: ZSL (2025). National Red List. Zoological Society of London. Available at: https://www.nationalredlist.org

This page: SpeciesRadar (2025). Fringe Horned Mason Bee (Osmia pilicornis). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/fringe-horned-mason-bee

Full citation guide & data usage terms