Updates & News

Archive: July, 2011

July 27, 2011

There are many species of mason bees, 120 in North America alone. Mason bees do not produce honey, instead females gather pollen for their larvae. Mason bees are small and easily confused with flies, however they have longer antennae, smaller eyes and four wings. Females are larger than the males, about 3/4″ and 1/2″ in length respectively, and the females have shorter antennae. They are incredibly gentle bees and although the females can sting, they very rarely do and do not even act aggressive at their nests. A Blue Orchard Bee’s sting has very low venom and produces the equivalent of a mosquito bite.

They have a very short active life, only foraging for 6-8 weeks in the spring, usually sometime during March, April or May. Males emerge first and do a little pollinating before waiting for the females to emerge. Once the males mate they die shortly thereafter. The females emerge two weeks after the males, mate and start to build their nests in holes. Mason bees do not make their own holes, in a natural setting they’ll use snags or old trees and will also make use of human structures such as shake siding and even outdoor furniture.

They lay eggs in their nests, upwards of 9-11 in each hole, leaving pollen with the eggs and then use mud to seal the egg and pollen in an individual chamber. The eggs hatch into larvae and feed off of the pollen before creating cocoons which the adults will stay in as they overwinter.

In the Pacific Northwest the Blue Orchard Bee (Osmia lignaria), has certain benefits over the honeybee such as foraging in the cold weather or light rain. They also stay close so it’s easier to target certain plants such as fruit or nuts trees. Blue Orchard Bees do not compete with the honeybee and they can even work alongside each other. In addition, the Blue Orchard Bee is not choosy about their pollen and will visit a wide range of flowers. They are messy pollen gatherers unlike the honeybee who packs wet pollen neatly onto their leg. The Blue Orchard Bee gathers the pollen, but being dry, much of it falls off and as a result, they pollinate nearly every flower they visit. One Blue Orchard Bee can pollinate 2,000 blossoms in a single day, the equivalent of what 100 honeybees can do.

Like most other pollinators, landscaping can help attract mason bees. Native spring flowers are perfect for the Blue Orchard Bee because they emerge in the spring and don’t have a strong pollen preference. Composite flowers with open petals are easier for the mason bees to harvest pollen from, and deep flowers, such as lilac are more difficult. Because they don’t forage too far from their nest sites, the flowers need to be within 300′ of a nest structure.

They also require a source of mud which they use to divide the chambers of their nest, and the mud needs to consist of more clay than sand. While this isn’t usually a problem in western Washington, if there is no close mud source, one can be created.

The third essential is to provide nest shelters. The basics of a mason bee nesting hole is a 5/16″ hole at 6″ deep. There are many materials for making holes, paper tubes with a paper insert are perhaps the best solution, but reeds also work well. Plastic straws are not good because the dampness of the pollen in the nest compartments is trapped, and can end up killing cocoons where paper pulls the moisture out. Wood blocks are not ideal either because they can be difficult to clean and inspect, although using the paper inserts in wood blocks is an option. Mason bees require a clean hole and if a block of wood is reused it can contain a build-up of pests.

The paper straws or reeds need to be protected in some type of shelter that will keep them dry. Anything from manufactured structures to a plastic soda container can work for this. The shelter should be placed where it gets morning sun to help the bees warm up in the morning. It should also be placed so that the open front is out of the direct rain and wind. Also avoid putting it too near bird feeders or over water. Mason bees identify their hole with scent, but they have to get close to smell it. Stacking the straws so that some stick out further than others helps the bees to identify their own hole.

For more information about attracting and raising mason bees visit The Metropolitan Field Guide.

Thanks Bon Appetit and Slow Food, for screening Vanishing of the Bees- it was a great turnout! I saw the movie once before, and it was interesting to pick up on things I hadn’t noticed when I saw it the first time.

- Sarah

Hi folks,

For those of you not on Facebook (most of our updates are there) -I just wanted to pass on that there’s a free screening of Vanishing of the Bees tonight at Seattle University’s Pigott auditorium. The movie is kindly hosted by Bon Appetit and Slow Food Seattle, and they moved to a bigger space so there’s still spots available. Corky Luster from Ballard Bee, Rob Stevens of Fairview Farm Apiary, and I will be there for the Q and A after the movie.

For details:




In the Pacific Northwest there are over a dozen different species of bumble bees, close to 50 in North America and over 250 species world-wide. Bumble bees are members of the Apidae family which also includes honey bees and carpenter bees. In the Pacific Northwest they vary in color, some with red, white, pale yellow, and orange, but the most familiar are black and yellow.

The various species are gentle and unlikely to sting unless their nests are disturbed, in which case they can defend their nests aggressively. Like the honey bee, they are social insects and nests contain many individuals. Unlike the honey bee, bumble bees nests are annual, meaning the nest dies off each year. They are large and very hairy and the females carry pollen moistened by nectar in their baskets, which are structures on their hind legs that fill with pollen, but not easily seen when empty.

They are some of the earliest bees to emerge in the spring and stay around the longest, often the last to be seen into the fall. Bumble bees can regulate their own body temperature by shivering or basking in the sun. This enables them not only to stay active longer during the season, but also during wet or cooler weather. They visit a variety of flowers throughout the season and as such require many different plants that bloom during the full season. They are also important pollinators of a wide range of crops such as watermelon, tomatoes and blueberries.

In the spring new queens emerge from their migration in search of a new place to build a nest. They nest socially with one queen starting her own colony.  The queen will produce an initial batch of worker bees to take over the foraging at which point she will start laying eggs around wax pots she creates to hold pollen and nectar. Near the end of the season the queen will produce a few males which will leave the nest to find mates and not return. At this time she also produces new queens. At the end of the summer nearly all of the colony will die, including the old queen, leaving only a few queens who will leave to mate before hibernating and starting new colonies the following spring. The new queens hibernate underground by digging several inches under either soil or leaf litter.

Bumble bees will make use of a wide range of nesting places including under dead wood, in a tree cavity, in old nests from birds or mice or man-made boxes or shelters. In an urban environment they will also nest in building walls, bird houses, rock walls and other urban debris. The basic requirements for built bumble bee nests are a supply of dry insulation materials and an undisturbed area. See Landscaping for Wildlife in the Pacific Northwest or Attracting Native Pollinators: The Xerces Society Guide to Conserving North American Bees and Butterflies and Their Habitat. It’s best to locate them away from people and activity where they won’t be disturbed unnecessarily and there’s less risk of seeming like a threat to them.

There are many common and native plants that will attract bumble bees. Because they are large, they will forage as far as a mile or more away from their nest location. Plants they prefer include those listed below as well as Bee Balm, Blackberry, Blueberry, Fireweed, Goldenrod, Huckleberry, Phacelia, Salal, Spirea.

For more information about bumble bees visit The Metropolitan Field Guide.