Did you know that …
- Somewhere between 75% and 95% of the world’s flowering plants depend on pollinators. 
- 30% of the food we eat comes from crops that require pollination in order to grow. 
- There are more than 20,000 known species of bee in the world and approximately 500 species live in Oregon. 
With spring here, gardens will soon be buzzing with pollinators – and not only the honeybees! Prior to the honeybee’s introduction to the Pacific Northwest in the 1860s, wild bees fulfilled most of the region’s pollination needs. These local bees are still the most important for pollinating native plants and helping maintain biodiversity in the Willamette Valley. Additionally, native bees play a large role in crop pollination. They are often better pollinators than honeybees because they spend more time on each flower, therefore helping to transfer more pollen.
Most of the Pacific Northwest’s native bees are solitary, meaning they don’t form complex colonies with divisions of labor, like honeybees do. Solitary bees either dig nests in the ground or find hollow stems to occupy. Because most native bees are solitary, they don’t have a hive to protect and are therefore much less likely to sting than honeybees.
Causes of Bee Decline
Unfortunately, populations of both native bees and honeybees are declining at a rapid pace. As pollinators, bees play an essential part in every aspect of ecosystems. They support the growth of trees, flowers, and other plants, which serve as food and shelter for creatures large and small. Habitat loss and fragmentation are major drivers of worldwide biodiversity loss. Habitat fragmentation is a process in which an expansive area of habitat is broken into smaller patches that are disconnected from one another. Even these remaining habitat fragments are losing value due to the spread of invasive plants. These invasive plants outcompete native plants that most bee populations rely on for nectar and pollen.
Similarly, climate change is causing a decline in bee populations. As average monthly temperatures rise, flowers bloom earlier in the spring. This creates a potential mismatch in timing between flowers producing pollen and bees being ready to feed on that pollen. Even just a few days of mismatch can have drastic negative effects on bee health, which causes them to reproduce less and be less resistant to predators and parasites.
Native Bees in the Pacific Northwest
Of course, when you are trying to contribute to bee conservation, it can help to know a little more about what you are trying to protect. Here are a couple of profiles of native bees that can be found in Washington County.
Mason Bees (Osmia)
Mason bees are named for the way they use mud as a building material to create cell divisions within their nests. Like most of Oregon’s native bees, mason bees are solitary and make their nests in naturally occurring above-ground holes or hollow stems. They are very efficient pollinators and are one of the first bees to emerge from winter hibernation. Mason bees are active from spring through early summer. Planting common camas (Camassia quamash), Oregon grape (Mahonia aquifolium), or Indian plum (Oemleria cerasiformis) can be particularly beneficial for mason bees.
Leafcutter Bees (Megachile)
Similar to mason bees, leafcutter bees like to make their nests in naturally occurring above-ground holes or hollow stems. Unlike mason bees, leafcutter bees use cut sections of leaves or petals to make cell divisions within their nests. Hence the name! While leafcutters can cause some superficial damage to plants in your garden, they more than make up for it as being active mid to late summer pollinators. Planting Oregon crabapple (Malus fusca) and snowberry (Symphoricarpos albus) is particularly beneficial for leafcutter bees.
How You Can Help Native Bees
Plant a Pollinator Garden
You can help conserve our native bees by planting plants in your yard with year-round, continuous bloom. Focus on planting native species because ornamental plants, while showy, often produce less pollen bees rely on.
If you want to go a step further, you can remove or reduce the size of your lawn. A perfectly manicured lawn reduces an area’s biodiversity and is often inhospitable to wildlife, including bees. Reducing the size of your lawn by creating pollinator gardens increases habitat, which will provide shelter and food for native bees and other types of pollinators.
Plant native plants from your ecoregion. Using locally native, flowering plants is the best option for supporting your local bee population. Native bees and native plants have become mutually adapted through millions of years of partnership with one another. Finding and planting the right plants makes a huge difference in the health of native bee populations. To find more native plants that are beneficial to local bees, visit the Xerces Society’s Maritime Northwest Region Pollinator Plant List.
Create Habitat for Native Bees
There are many ways you can create habitat for native bees. A simple bare spot here and there (no mulch or grass, just bare soil) may be enough for a collection of ground nesting bees. A sand pile may be even better. Standing dead trees are also important nesting habitats. If you cannot tolerate a dead tree on your property, it may be possible to keep a stump or standing log and use it as an attractive planter. Perhaps it will, in turn, provide nesting space for bees. These types of habitat will also provide shelter and shade for bees to escape extreme heat.
You can also build or buy your own bee house. There are many on the market, and it is relatively easy to build your own. Hollow paper tubes, about the size of drinking straws, can be used by mason bees and leafcutter bees as a nest. Or try tying up a bunch of hollow twigs, such as elderberry, or paper drinking straws and pack them into a container such as a small milk carton and place them horizontally. Simple, fun activities like these go a long way in helping native bees.Mader, E.; Shepherd, M.; Vaughan, M.; Black, S.; & LeBuhn, G. (2011). Attracting native pollinators: protecting North Americas bees and butterflies: The Xerces Society Guide. North Adams, MA: Storey Pub.  University of California – Berkeley. (October 2006). Pollinators Help One-third of the World’s Food Crop Production. ScienceDaily. Retrieved March 20, 2020 from www.sciencedaily.com/releases/2006/10/061025165904.htm  Kincaid, S.; & Shahan, T. (2017). Common bee pollinators of Oregon crops. Salem, OR: Oregon Department of Agriculture, Insect Pest Prevention & Management.