Sharp-tailed bees

How to recognise it

Medium bees with a distinctly conical, sharply tapering abdomen ending in a point in the female and in several small spines in the male. Boldly marked with bands of white or silver hair on a black body, sparsely haired and hard-shelled. Females have no pollen brush of any kind.

• A sharply pointed, cone-shaped abdomen unlike any other bee's — the single best character.
• No pollen-carrying hairs anywhere on the body.
• Sparse hair with crisp white or silver bands, and a hard shiny cuticle.
• Seen flying slowly and searching around bee hotels, hollow stems and leafcutter nesting areas.

Body length 7–17 mm (typically 11 mm).

Biology

Social organisation

Cleptoparasitic — lays in other bees' nests

Builds no nest and gathers no pollen for her own young, laying instead in another bee's provisioned cell. Sometimes called cuckoo bees.

Nesting

Builds no nest

Builds nothing. The female finds a leafcutter cell that has been provisioned and sealed, uses the pointed tip of her abdomen to cut through the leaf wall, and inserts an egg into the cell — sometimes into the cell wall itself, so that it hatches after the host has finished sealing.

Carries pollen

Carries no pollen for young

On the wing

May to September

Timed to leafcutter flight periods.

Lifecycle

1. 1SearchingThe female patrols host nesting areas — bee hotels, hollow stems, banks — testing tubes and cavities. Her emergence is timed to her host's, which is why Coelioxys appear at bee hotels shortly after the leafcutters do.
2. 2Egg insertionShe slits a sealed cell with her abdomen tip and inserts an egg, then reseals nothing and leaves.
3. 3Host eliminationThe first-instar larva has large sickle-shaped mandibles used specifically to kill the host egg or larva, and then moults into an ordinary grub to eat the pollen provision.

Where it lives and what it does

Habitat

Wherever leafcutter bees nest: gardens, bee hotels, hedgerows, brownfield land, heath and woodland edge.

Distribution

Worldwide wherever megachilid bees occur, with high diversity in warm temperate and subtropical regions.

Behaviour

Slow, deliberate and searching rather than purposeful. The characteristic sight is a sharp-tailed bee working methodically along a bee hotel, investigating each tube in turn — which is exactly what a leafcutter never does.

Pollination role

Negligible as a pollinator. It visits flowers only for its own fuel and carries no pollen deliberately. Its ecological role is as a top-level specialist whose presence indicates a substantial host population.

Incidental only.

What it forages on

Visits flowers for nectar only, and is unfussy about which.

Honey

Produces no honey

None. No nest, no colony, no stores.

Relationship with people

How people interact with it

Encountered mainly by people who run bee hotels and notice an odd pointed bee investigating the tubes. The usual instinct is to remove it, and the better response is to record it — a bee hotel with cuckoo bees at it is a bee hotel that is genuinely working.

Conservation

Several species are scarce and, as with all cleptoparasites, they decline faster than their hosts and recover more slowly. Their presence is a reasonable indicator that a leafcutter population is large enough to be self-sustaining.