Japanese orchard bee

How to recognise it

A stocky mason bee of roughly honey bee size, covered in dense gingery-brown hair, with two small horns on the female's face used to tamp mud. Very similar to the European red mason bee, to which it is closely related.

• Gingery-brown and stocky, with two small facial horns in the female.
• Pollen carried on the underside of the abdomen.
• Carrying mud into tubes and reed bundles in early spring.
• In Japan and eastern North America; not native to the latter.

Body length 8–14 mm (typically 11 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; Hollow stems and plant cavities

Uses existing tubular cavities of 7-9 mm, and in Japanese orchards is managed with bundles of cut reeds set out in shelters. Cells are separated by mud partitions and sealed with a thick mud plug, and females return reliably to the same bundle.

Carries pollen

Scopa on the underside of the abdomen

On the wing

March to June

Lifecycle

1. 1Managed emergenceCocoons are overwintered at controlled temperature and warmed to release at bloom.March to April.
2. 2NestingFemales provision cells for four to six weeks and die before their offspring hatch.
3. 3Harvest and storageReed bundles are collected in autumn, cocoons extracted, cleaned of pollen mites, and stored cold until spring.Roughly ten months.

Where it lives and what it does

Habitat

Orchards, woodland edge, gardens and hedgerows.

Distribution

Native to Japan, Korea, China and far eastern Russia. Introduced to the United States in the 1970s and now naturalised across much of the east.

Behaviour

Fast, cool-tolerant and clumsy inside a blossom, which is exactly why it pollinates so well — dry abdominal pollen sheds readily and the bee moves between trees rather than working one methodically. Japanese growers report that a few hundred females pollinate an orchard as effectively as several honey bee colonies.

Pollination role

Outstanding on apple and other tree fruit, and the basis of a large share of Japanese apple production. Adoption there is far more advanced than anywhere in Europe or North America.

Among the most effective apple pollinators known, per individual.

What it forages on

Spring blossom, particularly the rose family.

Honey

Produces no honey

None. One pollen loaf per cell, no colony.

Relationship with people

How people interact with it

One of the clearest demonstrations anywhere that a solitary bee can be managed commercially at scale. Japanese apple growers adopted it from the 1940s and it now handles the majority of the crop in some prefectures.

Management

Managed with reed bundles or drilled blocks, autumn cocoon harvest, washing to control pollen mites, and cold storage to time emergence. Skipping the cleaning is what turns a managed population into a parasite reservoir.

Conservation

Not threatened. In North America it is an introduced species that has naturalised widely, and there is active concern about competition with and pathogen transfer to native Osmia — a reminder that a useful pollinator is not automatically a harmless one.