The buzz on bees

By Maria MacRae
May 1, 2008

A Bee’s Life The life cycle of a bee has four stages: egg, larva, pupa and adult. The vast majority of our native bees build their nests in the ground. Most of the rest nest in holes, dead trees or plant stems. The female creates cells within the nest that are first made waterproof and then provisioned with pollen and nectar as food for the larvae. She lays an egg in each cell. Exactly how they build their nests and line the cells can vary greatly from species to species. Some bees use pieces of leaves or petals to line the cell; others use mud, tree resin or a Cellophane-like substance that they secrete themselves. Although solitary bees nest separately, some may build their nests in groups, possibly to take advantage of a good nesting site. The females of other species may share a common tunnel but build their own egg chambers branching off from the tunnel. -MM

Let’s face it — most bees are generally misunderstood and unappreciated, despite their diversity and importance as pollinators. The roughly 800 species of bees in Canada come in a wide range of shapes and sizes.

When people think of bees, most think of the honey bee (Apis mellifera), but this species is not native to Canada. It was introduced from Europe almost 400 years ago. Valued for its production of honey, beeswax and other products, it is also used by many farmers for crop pollination. Honey bees are indeed extremely valuable, but many native bees, such as bumble bees or mason bees, are more effective and efficient pollinators. Also, some native bee species emerge earlier in the year than honey bees, making them important pollinators of early spring blossoms.

Unlike most of our native bees, honey bees are also well known for aggressively defending their nests. Most of our homegrown species are solitary, which means that each female prepares her own nest, provisions it with food for her offspring, lays her eggs and then provides little further care. Because they do not have large nests or colonies to defend, solitary bees tend to be much less aggressive, stinging only if trapped, slapped or handled. Some don’t even defend themselves at all.

Bumble bees are the most social of our native bees. They form a temporary colony that starts with just the queen in spring. She lays her eggs and forages for food for herself and her larvae until the first workers come to maturity and start to help her out. Males and new queens are not produced until the end of the season. The colony breaks up at the onset of winter, and the queens are the only ones to survive to the spring.

Bumble bees are aggressive in defending their nest if disturbed. But away from the nest, like any bee, they are unlikely to sting unless threatened.

Some bees, known as cuckoo bees, don’t build a nest at all. Instead, like their feathered namesake, they lay their eggs in the nests of other bees. Because they take advantage of the food that other bees have gathered for their larvae, cuckoo bees only need to visit flowers to feed themselves rather than having to gather food to bring back to their nest. This means they lack the pollen-collecting hairs seen on other bees and appear rather hairless as a result. 

Many people find it easy to confuse bees with wasps. Although the two types of insects belong to the same order (Hymenoptera), they behave differently.

While many wasps are parasitoids — meaning their larvae develop in or on other insects — it is the stinging wasps that most people fear. These species include the social wasps, such as yellow jackets and hornets, which are known for their aggressiveness; they have developed stingers to allow them to immobilize their prey. Bees, which feed their young on pollen and nectar instead of insect prey, are less aggressive than their hunting cousins.

Native North American bee species, like some of our other pollinators, are under threat from habitat loss, pesticide use and other hazards. By creating a pollinator-friendly garden (see “Protect Our Pollinators,” Canadian Wildlife, March/April 2008) you will be helping our native bees. Two key features of good bee habitat are a diversity of bee-friendly flowers and good nesting sites. By adding a few of their favourite plants to your backyard, you can help keep our summers humming.

Maria MacRae is manager of CWF’s backyard habitat program.