Essential Facts about Canada’s Native Bees and Wasps

There are over 800 species of bees native to Canada (200+ in the the Greater Toronto Area); some 5,000 bee species in North America and more than 20,000 species worldwide.  The highly social European honey bee (Apis mellifera), the primary bee species managed for crop pollination and honey, was initially introduced to North America and most other parts of the world from Europe.

(Click image to enlarge; read fig. 2.2 here).

Bees, which evolved from wasps, are believed to have made the scene about the same time as flowering plants. Virtually all species subsist entirely on nectar and pollen from flowers.  Specialized, branched body hairs make them good at picking up pollen.  Most species of bees are solitary: they do not live in colonies, and do not make honey or beeswax. Females live more or less independently and construct cells for individually laid eggs out of a wide variety of materials. 70% of the solitary bee species in N. America live in the ground, and about 30% are twig- and wood-nesters, living in pre-formed cavities such as beetle bores and hollow stems in bramble. There are various flavours of ‘social’, described in more detail in the article “Bees of Eastern Canada” and in the book “Keeping the Bees” by Laurence Packer (see ‘resources pages’). Solitary bees do not defend their nests, except from their enemies such as cuckoo bees and wasps, which sneak into their nests, and occasionally birds or one another. They do not sting unless trapped or handled.

Wasps are largely carnivores. Many solitary wasp species have similar nest construction methods to solitary bees. Wasps also pollinate, though as their hairs are not branched, most do so to a much lesser extent than do bees. Like bees, most species of wasps are solitary (do not live in hives), living here and there in bramble and earth, etc. They, too, do not sting unless trapped or handled. Social wasps such as hornets can be dangerously aggressive in defending their nests.

Large, furry Bumble bees are among the most widespread and critical pollinators native to North America. Their colonies in nature often live underground in insulated hollows such as discarded mouse nests; they will also nest in discarded upholstered furniture or inside fiberglass-insulated walls. Started by single queen bees, their social colonies grow throughout the summer months and naturally die off by the first frost, with numbers per nest that range greatly from the Arctic to the South. In the autumn, the mated new queens then find different underground locations in which to over-winter to start a new colony cycle the following Spring. This annual lifecycle differentiates them from honey bees, in which perennial colonies can last indefinitely. Bumble bees do defend their nests, but otherwise do not sting unless trapped or handled.

Illustrations above and top from the book, “Bienen, Hummeln, Wespen im Garten und in der Landschaft” (colour); and from Bumblebee Economics (by Bernd Heinrich), diagrammes by Celeste Green and Phyllis Thompson (used with permission).

See also, the following:

The Bee Genera of Eastern Canada, CJAI 03 September 25, 2007 , Laurence Packer, Julio A. Genaro and Cory S. Sheffield

About Bees, Habitat and Coevolution

A male sweat bee (genus Lasioglossum) on an Autumn dandilion. By Rob Cruickshank.
Robert Cruickshank
Masked bees Hylaeus emerge from bamboo tomatoe stake. By Rob Cruickshank.

Some thoughts on bee biodiversity:

Of the variety of earth’s pollinators, bees are responsible for the majority of “pollination services” to flowering plants. The close synergistic relationship between plants and pollinators suggests that bee biodiversity—and by extension, plant and ecosystem biodiversity—is central to food security and to the health of the biosphere as a whole.

Human beings have widely replaced domesticated honey bee species historically used in Asia, India, Africa, Mexico and other places with domesticated western honey bees. “Of the more than 19,000 species of bees, perhaps a dozen are honey bees, fewer than five hundred are stingless bees” (cousins of honey bees which also produce honey)*.

The presence of managed honey bees in an ecosystem may put further pressure on diverse, native bee populations already established in a given area, which in turn may alter the ability of some native and non-native plants not easily pollinated by honey bees to thrive. The effect of honey bees competing for the same floral resources as bumble bees (where bumble bees are native) can be especially significant, but will depend on the degree of resource overlap with honey bees, and also if these resources are limited (tongue lengths and behaviours varying between species). Where resources in the environment are are sufficiently abundant, managed honey bees may have no effect; however, where floral resources are not abundant or varied enough to sustain both, the ability of bumble bees to bring pollen back to the nest is reduced and will affect their reproductive output.** “Bumblebee populations are built on their available food resources, and this suggests that introduced honeybees may be strong competitors in some areas.”***

*Keeping the Bees (Laurence Packer, Harper Collins, 2010)
**Competitive Interactions between the Invasive European Honey Bee and Native Bumble Bees
Diane Thomson, Ecology Vol. 85, No. 2 (Feb., 2004), pp. 458-470
*** Bernd Heinrich, bumble bee researcher, Professor Emeritus, University of Vermont, Department of Biology

Content prepared by Sarah Peebles. Thanks to James Thomson, Laurence Packer and Lincoln Best for editing and content assistance. Thanks to above-mentioned, Cory Sheffield and Stephen Buchmann for bee ID assistance, and to Nicolas J. Vereecken (Nico’s wild bees & wasps) and Bernd Heinrich for illustrations.

Some quotable quotes:

“Because of fluctuating conditions, it is probably not optimal for a plant to evolve too tight a relationship with any one pollinator.  They must hedge their bets and maintain a hierarchy of pollinators.  Some apparent inefficiency in the system at any one time may thus be necessary to long-term optimality.”

“…Although the number of [bee] species currently managed for pollination in North America is comparatively small, native wild bees are thought to be responsible for quite a large proportion of the economic benefits attributed to honey bees (Buchmann and Nabhan, 1996).  Sometimes, it is not only the number of visits to a flower, but also the diversity of bee species visiting (controlled for total number of insect visits) that determines crop yield (Kremen et al., 2002).  Wild bees are also crucial for the pollination of most non-crop flowering plants, and thus play an even greater role in most terrestrial ecosystems (Kevan, 2001, 2003; Kevan and Imperatriz-Fonseca, 2002).”

“As the 20th century nears its close, most North Americans lack any mental image for this ‘biological diversity’ that scientists deem so important…. It [a pollination crisis] is not merely an issue for rainforest activists, vegetarians or beekeepers. It is an issue that can help us find common ground between farmer and forest ecologist, between beekeeper and Mayan shaman, between organic gardener, pest control operator, and bat conservationist…. We will need tales, fragrances, tastes and images that inform us about how the world works and what is at stake if we simply ignore the needs of pollinators and the habitats where they make a living.”
“Oceanic islands are no longer the most isolated ecosystems on this planet; some forest fragments now show the very same syndrome. These fragments can be thought of as islands awash in a terrestrial sea now stripped of many keystone mutualists including pollinating animals…  fewer “islands” these days are tropical paradises for pollinators, and nothing about forest, prairie, or desert patches in seas of degraded landscapes will remind us of a bygone once-pollinated and fruitful Eden.”

“Pollinators are essential to the stability of the global ecosystem itself… It is suspected that many thousands of pollinator species have become extinct over the past century as a result of worldwide, rampant land-use change and deforestation. With accelerating global biodiversity losses, estimates of the number of insect species alone that will go extinct by the year 2050 range into the hundreds of thousands. The impact on native plants and on crops cannot be predicted in detail, but will surely be enormous.”