Native Pollinators On Farms

Native Bees for Farms

Ontario has about 400 species of native bees, most of which are important pollinators because of their ability to attract and hold pollen grains on branched hairs on their bodies and because they visit flowers to obtain both nectar and pollen to feed themselves and their young.  These bees pollinate a wide variety of crops as well as many native flowering plants.  Pollination is the first step in the reproductive process in these plants and results in seed set and subsequent stimulation of fruit production.

Most of Ontario’s native bees are generalists, meaning that they forage for nectar and pollen on a wide variety of plants.  However, some bees are specialists on a particular genus of plants or even a particular species.  For example, squash bees are specialist pollinators of Cucurbita crops (pumpkin, squash, zucchini, and some gourds) and do not forage for pollen on any other plants.

Ontario’s native bees can be roughly grouped into two categories—those that are social and live in colonies, and those that are solitary, although there are some bees that are semi-social.  Social bees have a queen, female workers, and males that all live in a communal nest together and divide up the tasks of the colony among them.   Bumble bees are the most notable social bees among our native species, although some Halictid bees can also be social.  Bumble bees tend to be active as adults for an entire season, April to October.  Most of Ontario’s native bees are solitary. Among solitary bees, individual females build nests, provision those nests, and lay eggs without the help of other bees.  There may be one or more generations of offspring produced in a season, depending on the species.  Adult male solitary bees do not live in the nests that the females build.  Most of the lifecycle of solitary bees is spent in the immature larval or pupal stages.  Often the adult (pollinating) stage of the solitary bee is short-lived, especially if that bee is a specialist forager, although the exact details vary from species to species.

Here Farms at Work presents four groups of native bees that are especially important on farms because farming systems can be managed to encourage stable, reliable populations of these bees to provide essential pollination services.  These bees include bumble bees, mason bees, leafcutter bees, and squash bees.