Mason Bees


What is Pollination?

  • Pollination is the act of transferring pollen grains from the male structure of the flower to the female structure in order for the plant to produce seeds from which to reproduce.
  • Flowering plants have adapted numerous methods to get pollen where it needs to go. These include wind, water, birds, bees, butterflies, bats, and other animals that visit flowers.
  • These animals that transfer pollen are referred to as "pollinators". When pollinators are used by flowering plants, the plant usually offers an incentive to the pollinator, typically in the form of nectar or pollen.


Why Pollinators?

  • Pollinators help to sustain a healthy environment that supports wildlife and us, too. Approximately 1/3 of all our food sources would not exist without pollinators. We need pollinators... and pollinators need our help!
  • Many pollinator populations are in decline, due to extensive pesticide use and loss of natural habitats and native food resources.
  • We can help pollinators survive and flourish by supporting the creation of a pollinator friendly environment in our yards.


About Mason Bees

Mason Bees

  •  Mason bees are not aggressive
  • Mason bees are renowned for being amazing pollinators, especially for fruit trees, such as apples, pears, and peaches.
    • Increasingly, they are being reared commercially, particularly for fruit crop pollination.
  • They are generalists that love to visit a wide variety of early blooming flowers.
    • Spring flowering nut trees, flowering shrubs, and spring berry plants.
  • Successful pollination using mason bees does not require a large population of bees.
  • Unlike honey bees, mason bees carry pollen on their bellies rather than on their hind legs, this helps to make them highly efficient pollinators. A single mason bee will visit between 1,600 and 2,400 blossoms daily, and pollinate over 90% of them. 
  • Mason bees are tunnel-nesting, solitary bees, which means that every female is a "queen" who builds her own nest, gathers her own food, and lays her own eggs.
  • Although mason bees are solitary, they are often gregarious and will nest near other mason bees.
  • Mason bees lay their eggs in tunnel nests that are constructed in abandoned holes created by wood-boring insects, hollow plant stems, or artificial houses and tubes.
  • Females use clay to build partitions and seal the tunnel entrance. This unique behavior is what led to the name "mason" bee.


Be a Mason Bee Landlord

  • Mason bees are among the easiest bees to raise
  • Artificial houses provide a very acceptable nesting location for the female mason bees.
  • Mason bee houses are best mounted 6 to 7 feet off the ground to a structure that will not shake in the wind, with the entrance facing towards the east or southeast.Mason Bee House
    • Place the house near flowering plants, as mason bees only fly about 300' in search of nectar and pollen.
    • Try to install your bee house away from any bird feeders and bird houses
    • Keep a wet patch of bare soil or offer a plant tray of moist clay within 25' of the mason bee house as available materials for when they construct their brood cells.
    • To maximize the brood success, some references advise taking down filled nest boxes, and storing them in a dark unheated shed or garage during the winter and returning them outdoors in early spring.
      • This is to help protect your bees from predators and parasites. Rest assured that the majority of your mason bees will survive is the house is left outside during the winter.
    • Every mason bee house should be taken apart to clean and sanitize every few years.


A Year in the Life of a Mason Bee

  • The adults emerge from their nest in early spring as the temperature consistently reaches 50-55°F.
  • Once the females emerge, they promptly mate, search for cavities that are the right size and shape and go to work stocking their nests.
    • Mason bee season is over when the nesting tunnels are capped with mud. This usually happens by early summer.
  • Pollen and nectar are the favorite foods of their brood
    • Females collect the pollen, bring it to their tube-like nests, and knead it into pea sized ball, mixing it with nectar and their saliva.
  • The female lays only one egg in each brood cell and seals it off with a little mud wall.When she completes five to eight cells, she seals the tunnel's entrance hole with a thick mud wall.
  • Newly laid eggs hatch in approximately one week, with the larvae spending a month or more consuming the pollen ball.
  • In early summer, after the feeding period, each larvae spends a week spinning a thick silk cocoon.
  • By late summer, mason bees transform into fully-formed adults and remain dormant and safe inside their brood cells throughout the winter.
  • Early in the following spring the process repeats itself. The new generation chewing through their cocoon and mud walls to emerge into the world, usually in perfect timing with the early blooming trees, shrubs, and flowers.