HymenopteraColletidae

Chalk Yellow-face Bee

Hylaeus dilatatus

This record describes Hylaeus dilatatus (species). Recorded family: Colletidae. Recorded order: Hymenoptera.

Identification and Appearance

Chalk Yellow-face Bee - Hylaeus dilatatus

British representatives of the subgenus Lambdopsis are restricted to Hylaeus dilatatus and H. annularis (formerly H. spilotus).The females of both differ from other British Hylaeus in the reduced, circular (not wedge-shaped or linear) paraocular markings; the males have greatly dilated, yellow and black-marked, sub-rectangular antennal scapes (easily visible to the naked eye). Most solitary bees and wasps are difficult to identify, and can rarely be identified from photos taken in the field. All red-rated records should include a photo, or set of photos, showing the key characters, which may require the specimen. Please include a face shot, side, top and wings. Note whether male or female, explain how the specimen met the key characters and the key used. 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’). The species is often locally common on calcareous grassland, but has been reported from coastal sites, fens and open woodland. Univoltine; early June to late August or early September. As with all British Hylaeus, the females are often long lived (the males having a considerably shorter adult life). Nest burrows are made in old bramble stems and n the stems of some other plants.

Classification

Kingdom
Animalia
Phylum
Arthropoda
Class
Insecta
Genus
Hylaeus

Imported taxonomy record. Source availability varies; see the source references and editorial policy below.

Habitat and Range

Habitat

The species is often locally common on calcareous grassland, but has been reported from coastal sites, fens and open woodland.

Seasonal Activity

Univoltine; early June to late August or early September. As with all British Hylaeus, the females are often long lived (the males having a considerably shorter adult life).

Diet and Behavior

Life History

Nest burrows are made in old bramble stems and n the stems of some other plants.

Additional species information

Recorded status

Widely distributed, though local, in southern England; the range extends north to the Midlands (Leicestershire). In Wales, only recorded from South Glamorgan.

About Flies: the wider group

Order-level background for Hymenoptera, the group containing Hylaeus dilatatus. Species-specific details appear above.

Group overview

Hymenoptera includes over 150,000 described species of ants, bees, wasps, and sawflies. Earth harbors approximately 20 quadrillion (20×10^15) ants, with a combined biomass of ~12 megatons of dry carbon - exceeding the combined biomass of all wild birds and mammals (PNAS, 2022).

Ecological role of the group

About 35% of the world's food crops depend on animal pollinators. The chocolate industry, valued at over $100 billion, depends on pollinating flies and midges. Ants are the dominant soil engineers in most terrestrial ecosystems, turning more soil than earthworms in many habitats.

Economic and practical significance of the group

Pollinators contribute $235-577 billion worth of annual global food production (FAO). In the U.S., bee pollination alone benefits crops valued at $18 billion annually, and honey bees are responsible for $5.4 billion in agricultural productivity. Between April 2023-2024, 55.1% of managed honey bee colonies were lost. The U.S. bee population dropped from 5 million to 2.5 million.

Recorded sources for this group: FAO, USDA, EPA, PNAS (2022), US Fish & Wildlife Service. Imported estimates may describe particular regions or reporting periods.

Explore Hymenoptera families and species →

Photos of Chalk Yellow-face Bee (5)

Chalk Yellow-face Bee - photo 1
Chalk Yellow-face Bee - photo 2
Chalk Yellow-face Bee - photo 3
Chalk Yellow-face Bee - photo 4
Chalk Yellow-face Bee - photo 5

Frequently Asked Questions About Chalk Yellow-face Bee

What is Chalk Yellow-face Bee?

Chalk Yellow-face Bee (Hylaeus dilatatus) is a species in the family Colletidae, within the order Hymenoptera.

Where is Chalk Yellow-face Bee found?

Habitat: The species is often locally common on calcareous grassland, but has been reported from coastal sites, fens and open woodland.

When is Chalk Yellow-face Bee active?

Chalk Yellow-face Bee: seasonal activity - Univoltine; early June to late August or early September. As with all British Hylaeus, the females are often long lived (the males having a considerably shorter adult life)..

What is the life cycle of a Chalk Yellow-face Bee?

Nest burrows are made in old bramble stems and n the stems of some other plants.