The Value of Native Bees

Bees have always served a vital role in nature’s ecosystems.  Recently, scientists and apiarists have conducted intensive research on bees’ habitats and are alarmed about their decline in population. Our planet’s sustainability is dependent on a healthy bee population, so it’s in our best interest to protect the bees.

Most people are familiar with honeybees, but know little about native bees, even though they’re more efficient pollinators than honeybees. Ontario is home to about 300 species of native bees, 90% of which live in ground nests, hollow stems, and insect and woodpecker holes.  Two common types of native bees are mason and leafcutter bees. Female mason bees emerge in early spring and immediately begin to forage for pollen and nectar, which they collect from vegetation. Female bees pack this food into the far end of the nesting cavity until they determine that there’s sufficient food to feed the future young bees. The bee then lays an egg and seals the cell. This process continues until the entire chamber is filled with pollen/nectar/egg cells.

honeybee (left); mason bee (right)

Like the mason bee, the leafcutter bee raises its larva in a tube-shaped home and separates each larva in a cell. Mason bees use mud to create cell divisions within the nesting cavity, but leafcutter bees cut a circle in a leaf and wrap their young in a leaf blanket.  Leafcutter bees are smaller than mason bees and prefer 6mm diameter nesting holes, whereas mason bees like 8mm nesting holes. Male native bees don’t have a stinger and females will only sting if provoked. Because of their solitary lifestyle, native bees are not as susceptible to disease or parasites as honeybees are.

Promote a healthy bee population by building or buying a native bee home (see image below). The homes should be made of natural wood, not pressure-treated or particle wood. To build a home,

  • drill different sized holes from 5mm to 8mm in diameter into a piece of natural wood. The depth of the holes should be from 4” to 6” deep to support a healthy proportion of female to male eggs.
  • make sure that only one side of the holes is accessible. Fasten a flat piece of wood to one end of the block, which you can remove later when cleaning the holes.
  • ensure there are no splinters in the holes that could injure the bees.
  • locate the bee home in a secure and dry area, preferably facing the morning sun.
  • cover the front of the bee home with a wire mesh to give the bees a landing grid and to discourage predatory birds from approaching.

Bee homes will attract bees every year, but the homes should be cleaned each spring after the weather warms and the bee larvae from the winter have hatched.  Never use pesticides and chemical fertilizers. If you buy plants from greenhouses, confirm that no neonicotinoids were used in seeding them. Note that bees are attracted to flowering fruit trees and pollinator gardens containing such flowers as sunflowers, borages, coneflowers, lavender, lilacs, crocuses, marigolds, milkweed, snapdragons, and dandelions. Do your part to maintain the health of our planet by cultivating and supporting native bee populations.

~ written by Albert Sauer