Resin bees

How to recognise it

Very small and narrowly cylindrical at 6-8 mm, black and sparsely haired, with a notably large head and a pale-banded abdomen. Females carry pollen on the underside of the abdomen.

• Tiny, cylindrical and black, with a large head relative to the body.
• Nest tubes sealed with a shining, hard resin plug rather than mud or leaves.
• Almost always on composites — daisies, ragwort, hawkbits, knapweed.
• Uses very fine cavities of 3-5 mm.

Body length 6–9 mm (typically 7 mm).

Biology

Social organisation

Solitary

Each female builds and provisions her own nest with no workers and no caste. Most of the world's bee species.

Nesting

Existing cavities and tubes; Resin-lined cavities; Hollow stems and plant cavities

Uses very narrow existing cavities — old beetle borings in dead wood, fine hollow stems, and the smallest bee hotel tubes at 3-5 mm. Cells are separated and the entrance sealed with plant resin, which sets hard and glossy and is genuinely distinctive.

Carries pollen

Scopa on the underside of the abdomen

On the wing

June to September

Lifecycle

1. 1EmergenceAdults emerge in early summer, timed to composite flowering.June to July.
2. 2ProvisioningFemales collect composite pollen and seal cells with resin gathered from conifers and other resinous plants.Several weeks.
3. 3OverwinteringThe larva develops and overwinters in the resin-sealed cell.Roughly ten months.

Where it lives and what it does

Habitat

Gardens, brownfield land, woodland edge, heathland and old fence posts — anywhere with fine dead-wood cavities and abundant composites.

Distribution

Worldwide except Australia, with good representation across Europe, Asia and North America.

Behaviour

Quick and easily overlooked, and strongly tied to composites for pollen. The resin gathering is worth watching: the bee arrives at a conifer wound or a resinous bud, works a droplet free with the mandibles, and flies off with it held at the front — a difficult cargo to manage.

Pollination role

Useful pollinators of composites, and effective on small flowers that larger bees find uneconomic.

Moderate per individual and meaningful in aggregate on composites.

What it forages on

Composites strongly favoured, and several species are effectively restricted to them.

Honey

Produces no honey

None. One small pollen loaf per cell.

Relationship with people

How people interact with it

Almost never noticed, and another argument for bee hotels with much finer tubes than the standard sizes. A resin-sealed tube in a hotel is a good find.

Conservation

Widespread, and dependent on the coincidence of fine dead-wood cavities, resin sources and composites within a short flight.