Animal

Mason bee

Osmia spp.

Also known as: Orchard mason bee, Blue orchard bee

Solitary cavity-nesting native bees, ~140 species in North America. Active in early spring during fruit-tree bloom; metallic blue-black or dark coloration; smaller than honeybees, fast-flying, gentle. The orchard mason bee (Osmia lignaria) and the Japanese hornfaced bee (Osmia cornifrons, introduced and naturalized) are major commercial fruit-tree pollinators in the Pacific Northwest and Mid-Atlantic. A single mason bee pollinates an apple bloom approximately 80 times more efficiently per individual than a honeybee — they belly-flop directly into the flower's reproductive parts, while honeybees often visit flowers without pollen contact.

Biology

Mason bees emerge from overwintering cocoons in early spring, timed with fruit-tree bloom. Females are larger than males and emerge a few days later. After mating, each female:

Selects a hollow cavity (a hollow stem, drilled wood block, or paper tube of 6–8mm diameter)
Collects pollen and nectar; mixes them into a “bee bread” provision
Lays an egg on the provision; seals the cell with mud (hence “mason”)
Repeats — typically 5–10 cells per tube; all-female cells in the back, all-male in the front (males emerge first the following spring, ready to mate as females emerge)

A female completes her work in 4–6 weeks; she dies after laying her last egg. Eggs hatch, larvae consume the provision, pupate inside cocoons, and overwinter — emerging the following spring as new adults.

Why they’re efficient pollinators

Belly-flop foraging — mason bees throw themselves directly onto flowers, contacting pollen-bearing parts firmly
Pollen collected dry on body hair — the entire underside of the female is covered in dry pollen, brushing each new flower visited (vs. honeybees, which moisten pollen with nectar and pack it into leg-baskets, less of it transferring to the next flower)
Cool-weather active — mason bees fly at lower temperatures (50°F) than honeybees (60°F+), critical during early-spring fruit-tree bloom when weather is variable
Crop fidelity — mason bees stay close to nest (typically 100m); they pollinate [[the-orchard|the orchard]], not other neighborhoods

Commercial use

Orchard mason bees are sold as ready-to-emerge cocoons; growers place them in fruit orchards at bloom. The Japanese hornfaced bee (Osmia cornifrons) was introduced to U.S. orchards in the 1970s and is now naturalized; it’s the dominant Mid-Atlantic commercial mason bee. Native species (Osmia lignaria) are increasingly used in Pacific Northwest commercial orchards.

A few hundred mason bees can pollinate an acre of apple orchard — a job requiring multiple full [[honeybee|honeybee]] colonies.

How to host mason bees

Drill holes 5/16” diameter, 5–6” deep, into untreated wood blocks
Or stack cardboard tubes / hollow stems / specialized mason bee houses
Mount on the south or east side of a building, ~5–6 feet up
Provide bare soil with clay nearby for mason work
Plant early-spring flowers (willows, fruit trees, dandelions, redbuds)

Sources

The Bees in Your Backyard, Wilson and Carril
USDA Agricultural Research Service mason bee technical materials
Crown Bees / Pollinator Partnership materials

Rooted in life.

What links here, and how

Inbound connections from across the wiki, grouped by lens and by relationship. These appear automatically — every entity page declares what it links to, and that data populates here on the targets.

Nothing yet. This entry is currently one node away from the rest of the graph — links will appear here automatically as the wiki grows. Each new entity that mentions this one in its relations frontmatter shows up here.

0 inbound links · 3 outbound