Vernal colletes

How to recognise it

A large, densely furred plasterer bee with a gingery-brown thorax and a dark abdomen with pale hair bands, similar in build to the ivy bee but flying six months earlier and larger.

• Large and gingery, flying in March and April — no other Colletes is on the wing then.
• Massive nesting aggregations in sand dunes, sandpits and light soil.
• Clouds of males flying low over the emergence area, forming mating balls around emerging females.
• Found on willow catkins, which it depends on almost entirely.

Body length 12–16 mm (typically 14 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

Burrows in the ground

Digs burrows in light sandy soil, overwhelmingly in dunes, sandpits and heathland, and in aggregations that can run to tens of thousands of nests. Cells are lined with the cellophane-like polyester secretion characteristic of the genus, which waterproofs them in ground that drains fast and floods occasionally.

Carries pollen

Scopa — dense hairs on the hind leg

On the wing

March to May

Lifecycle

1. 1EmergenceMales emerge first in March and patrol the aggregation in large numbers; females follow days later.March to April.
2. 2MatingMales scramble around emerging females in dense mating balls — alarming to watch and entirely harmless, since males cannot sting.
3. 3ProvisioningFemales collect willow pollen through April, provisioning semi-liquid pollen-and-nectar mixtures in waterproofed cells.Four to six weeks.
4. 4OverwinteringThe larva develops on the liquid provision and overwinters in the sealed cell.Roughly eleven months.

Where it lives and what it does

Habitat

Coastal sand dunes, sandpits, heathland and light sandy soils with willow nearby.

Distribution

Across Europe from Scandinavia to the Mediterranean, and one of the most abundant spring bees on northern European dune systems.

Behaviour

A near-specialist on willow, with the whole life cycle synchronised to catkin flowering. The aggregations are among the most dramatic wild bee spectacles in Europe and are routinely mistaken for a swarm of something dangerous.

Pollination role

An important early pollinator of willow, which is itself the most important early pollen source in temperate Europe. The relationship is tight in both directions.

High on willow, and negligible elsewhere.

What it forages on

Willow overwhelmingly. Where willow is scarce it will use other early flowers, but the population depends on it.

Honey

Produces no honey

None. A semi-liquid provision sized for one larva in a sealed waterproof cell.

Relationship with people

How people interact with it

Encountered as a startling aggregation on a dune or in a sandpit, and almost always reported as a problem. Nothing needs doing; the bees are gone by May and the site will be used again next year.

Conservation

Widespread and locally abundant, and dependent on the coincidence of open sandy ground and willow. Dune stabilisation, scrub encroachment and sandpit restoration all remove nesting habitat.