What is the Mason Bee Survey about?

The blue orchard bee (Osmia lignaria) is a native solitary bee that many Oregonians rear in their backyards and small orchards. The bees is an excellent pollinator of fruit trees, but is also gentle and kept as a hobby in many of the state's gardens.

These bees, however, can develop diseases and populations of predators and pests can build up. In addition there are some new exotic bees and bee pests and predators that have been recently introduced into Oregon. We are looking for your help to establish baseline on the health of stocks of these bees, which ultimately will help track the health of these bees over time.

How to get involved?

Step 1.

Fill out the attached survey (see below) and we will mail you sample containers to return the cocoons to us.

Step 2.

Before you strip your blocks, take an image of the exposed nests with your camera. We will use this image to compare to the species in your cocoons in order to see whether bee species other than O. lignaria can be identified by the orientation and density of the cocoons in the block.

Step 3.

Take a sample of your cocoons at the time when you remove the cocoons from the block. It's important to take the samples BEFORE you clean the cocoons, because:

  • We don't want you to wash or clean these cocoons in any way
  • We want you to sample based on the arrangement of the cocoons in your nesting material.

You will get two vials, one for what appear to be healthy blue orchard bee cocoons, one for cocoons you suspect to contain exotic bees (see below).

Step 4.

Send your cocoons back to the Pollinator Health lab at Oregon State University for analysis. We will provide results back to you in the March 2022.

How to tell the blue orchard bee (Osmia lignaria) from the horned-faced bee (Osmia cornifrons)?

Of key concern to the state is the spread of an exotic bee that nests alongside our native orchard mason bee, namely the horned-faced bee (Osmia cornifrons). Although this bee has been in the Portland area for some decades, reports indicate that this bee has spread outside the Portland area. We are also looking for other exotic bee species during this survey.

Reports indicate that the difference between the blue orchard bee and horned-faced bees are best assessed before removing bees from their nesting material (see figure).

  • The horned-faced bee tends to be smaller and can have as many as 13-15 in a regular 6" tube.
  • In contrast, the blue orchard bees are typically larger, with around 8 bees per 6" tube.
  • The cocoons of the blue orchard bee tend to be browner in color.

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