Discover Native Bees as Pollinators

Guest column by Andrea Stevens

Photo credit: Andrea Stevens

On a recent sunny day in June, I sat on our porch steps soaking in the warmth and admiring a flowering chokeberry. I wasn’t alone in my appreciation for this diminutive tree. Bees of all sizes were bouncing from one flower cluster to another, happily drinking up the prized nectar. Sort of like free ice cream on the first day of summer.

Most pollinators are insects, but bees are one of the most important pollinator groups. This is because female bees purposefully collect nectar and pollen to feed their offspring. And in their travels, they carry pollen from flower to flower. With this pollen transfer, fertilization occurs, creating the seeds of future generations.

Pollination benefits the natural world –  and that includes us! Many claim that one in every three bites of food we eat is available because of pollinators. Wild pollinators – especially bees – have co-evolved with our native plants in ways that benefit both insect and plant. This synergy is vital to our natural landscapes.

There are about 4,000 species of native bees in the United States and more than 270 are native to Maine. The vast majority of native bees are solitary, meaning that each female prepares her own nest for her eggs. It’s encouraging to know that solitary bees rarely sting and are considered “gentle”.

The native mason bee (Osmia species) is solitary and named for its use of mud or chewed up leaves to separate egg cavities in their nest tunnels. The Maine Blueberry Bee (a mason bee) was found to be far more effective at pollinating blueberries than the non-native honey bee.

In contrast to solitary bees, social bees live together and share the chores among queen bees and workers. Bumblebees are probably the most familiar of social bees.

Photo credit: USGS Bee Inventory and Monitoring Lab

Both the Maine Blueberry Bee and bumble bees are able to “buzz-pollinate.” They vibrate while buzzing on a certain pitch which releases more pollen from flowers. Bees that have this ability are very effective pollinators!

European honeybees are widely used to pollinate agricultural crops, but have experienced declines in recent years due to disease and Colony Collapse Disorder. Native bees also face threats such as loss of habitat, pesticide use, disease, and changing conditions related to invasive species and climate change.

But there’s good news! We can help native bees by creating and enhancing their habitat in our own backyards. We can also document our observations of native bees and contribute to the knowledge base of this important group of pollinators. Below are some ideas and resources to get you started.

  1. Build a mason bee house. Mason bees lay eggs in tubes where each egg is enclosed in a nectar/pollen paste and eggs are separated by mud. To build a nesting house for mason bees, you need a structure and some tubing material. Here’s how we did it:
Photo credit: Andrea Stevens

Structure:  6 pieces of wood all ¾” thick: Two sides and a bottom (6” x 6¼” – 3 pieces); back (8” x 6¼”); top with overhang (6¼” x 7”); back post for mounting (11” x 3”). Nail pieces together.

Nesting tubes: Collect dried hollow stems of Japanese Knotweed or Phragmites and cut to approximately 6” lengths. The best time to do this is in the winter or other times of year if plants have been cut and cut stems have dried. 

Mounting: The bee house should be placed against a flat surface (house, garage, shed) with a south or southeast exposure, approximately 8 feet from the ground and away from bird feeders.

Timing: Bee houses can be set out when flowers begin to bloom in the spring. The blue orchard mason bee begins to mate when apples flower.

Maintenance and alternative small houses: Replace hollow stems every couple of years. As an alternative, place small bundles of stems around your property and discard and replace when needed.

If a deeper dive into different methods and styles of mason bee houses appeals to you, check out the Xerces Society’s publication on building mason bee houses here.

  1. Plant a pollinator garden with native perennial plants. Try to choose a diversity of native species that flower throughout the growing season. There is lots of information online about pollinator-friendly plants and habitats. Check the University of Maine Cooperative Extension (https://extension.umaine.edu/gardening/manual/plants-pollinator-gardens/), the Portland Pollinator Partnership (https://portlandpollinators.org), and Wild Seed Project (https://wildseedproject.net/creating-native-plant-corridors-for-pollinators-and-wildlife/). Maine Audubon sells native plants in June and throughout the summer, as long as supplies last (https://shop.mainenativeplants.org/)
  2. Participate in citizen science projects by submitting observations to the Bumble Bee Watch (https://www.bumblebeewatch.org) or another citizen science initiative that promotes pollinator research in communities.

Additional Resources:

Couto, A., and A. Averill. 2016. A Review on Bees: All about Bees and How We Can Help! University of Massachusetts Extention (pdf).

Mader, E. et al. 2011. Attracting Native Pollinators: The Xerces Society Guide. Storey Publishing.

University of Maine Cooperative Extension. 2004. Understanding Native Bees, the Great Pollinators. Bulletin #7153 (pdf).

Xerces Society. 2019. Habitat Assessment Guide for Pollinators in Yards, Gardens, and Parks (pdf).

Xerces Society. 2017. Pollinator Plants Northeast Region (pdf).

Xerces Society Pollinator Conservation Resource Center (https://www.xerces.org/pollinator-resource-center)

Xerces Society Invertebrate Conservation Fact Sheet. 2013. Tunnel Nests for Native Bees – Nest Construction and Management (pdf).

Young, B.E., D. Schweitzer, N. Sears, M.F. Ormes. 2015. Conservation and Management of North American Mason Bees. NatureServe (pdf).