Pollinators

Pollination is the act of transferring pollen grains from the male anther of a flower to the female stigma of another flower of the same species. Successful pollination is the first step in the process that results in the production of healthy fruit and fertile seeds, allowing plants to reproduce and create the next generation.

The spread of pollen is essential for the survival of flowering plants, many of which constitute the crops and food such as fruits, vegetables and nuts that humans eat. About 80-90% of all flowering plants and over three-quarters of the staple crop plants that feed humankind rely on animal pollinators, with pollinators being responsible for one in three bites of food we eat. It is not only humans that use plants as a food source, but also herbivores, who may in turn provide food for carnivores. Without pollinators, the human race and all of earth’s terrestrial ecosystems would not survive.

Pollination can happen through self-pollination, wind and water pollination, or through the work of pollinators. These are animals or insects that carry pollen from one plant to another as consequence of their activity on a flower and they are responsible for 80% of all plant pollination. There are about 200,000 different species that act as pollinators. Of these, approximately 1,000 are hummingbirds, bats and small mammals. The remainder are insects such as beetles, bees, ants, wasps, butterflies and moths. 

Pollinators visit flowers in search of food, mates, shelter and nest-building materials. They drink nectar or feed off of pollen and transport pollen grains as they move from spot to spot, thereby starting the fertilization process in the plant. In turn, the sugars in nectar and the proteins, fats, vitamins and minerals from pollen grains power the pollinators growth, metamorphosis, flight and reproduction. There is a bond where neither the plant nor the pollinator populations can exist without each other. Should one or the other disappear, each is only one generation away from disaster.

Plants have differing flowering times throughout the growing season which decreases competition for pollinators and helps to provide pollinators with a constant supply of food. From the first warmth in late winter through spring and summer, until frost in late autumn, flowering plants are available to their pollinators providing pollen and nectar in exchange for their pollination service.

Plants have evolved many intricate methods for attracting pollinators. These include visual cues such as colour or showy petals, using scent as an attractant,  providing a food source and even entrapment. Animal-pollinated flowering plants produce pollen that is sticky and barbed to attach to the animal and thus be transferred to the next flower. Likewise, many pollinators have evolved specialized structures and behaviors to assist in plant pollination such as the fur on the face of  a bat or barbs on the legs of an insect.

The most widely known pollinator is the bee. Bees pollinate as they move from flower to flower to drink nectar and to collect pollen on their hind legs. The most widely known bee is the honeybee. Honeybees are not native to Canada, however they are highly managed for their honey production and for pollination services for commercial crops. The honeybee is only a small part of the bee world. There are approximately 20,000 species of bees worldwide with about 300 native to Alberta. Most bee species are solitary (bees that aren’t social and don’t live in a hive). With solitary bees, the female constructs and tends to her own nest without the help of others. Native bees such as green sweat bees, mason bees, bumble bees, polyester bees, mining bees, and leafcutter bees all work as pollinators.

Another well-known pollinator is the hummingbird. With their long beak and tongue, hummingbirds prefer trumpet-shaped flowers. Their main interest is in the flower nectar however they do transfer pollen that gets on their body from flower to flower as they move about. The main hummingbird pollinators in Alberta are the Rufous Hummingbird and the Ruby-throated hummingbird.

Butterflies drink nectar with their long mouth part or proboscis. The long proboscis helps them to pollinate flowers that bees can’t reach. As they move on a flower, their body and legs pick up pollen which is then transferred from flower to flower.

Moths pollinate flowers in the same way as butterflies however they do most of their pollination work at night. Alberta is home to one of the few moth species that do act as pollinators, the aptly named hummingbird clearwing moth (Hemaris thetis). This moth flies and feeds on flower nectar in the daytime, and even mimics a hummingbird’s flight and hovering behaviours. 

Many pollinators are in decline for a number of reasons including loss of feeding and nesting habitat, pesticide use and climate change. The Rotary Butterfly and Hummingbird Gardens are designed to attract and provide habitat for these beneficial creatures. They are many ways that individuals can help pollinators in their own gardens such as: 

Plant native Alberta species in your garden 

• Use a wide variety of plants that flower at different times from early spring until late fall 
• Plant flowers in clumps so they are easier for pollinators to find and to provide better foraging efficiency 
• Consider planting night-blooming flowers that will support moths and bats 
• Avoid modern hybrid flowers which are often bred to exclude nectar, pollen and scent 
• Eliminate pesticides whenever possible. If you must use, spray at night when pollinators are not usually active and consider leaving some areas untreated as a refuge habitat for pollinators that can then re-colonize treated areas 
• Grow plants that are hosts for larvae – plants to feed caterpillars 
• Provide additional nectar sources such as a hummingbird feeder 
• Provide a feeding station for butterflies such as a container of fruit with a little water 
• Provide water by filling a shallow birdbath or container with stones or gravel   

We can also assist pollinators by providing a suitable habitat in our yards. Some habitat requirements are as follows: 

• Solitary bees nest in dead trees, fallen branches, hollow stems, or in bare and partially vegetated soil where water won’t pool.  
• Bumble bees nest in cavities underground, often in old rodent burrows or in hollow trees or beneath clumps of grass 
• Butterflies and moths use the leaves and stems of host plants for eggs and larvae and small woodpiles are used by species that winter as adults 
• Hummingbirds nest in trees, shrubs and vines 
• Bats reside in many places such as large trees, caves or cracks in buildings  

To provide pollinator habitat, where possible, leave standing dead trees, fallen logs or piles of twigs and bare patches of soil. Dense plantings of shrubs will provide nesting sites for hummingbirds and a bat house will provide a roosting place for bats. If you build it, they will come! 

Pollinator Partnership, About Pollinators

United States Department of Agriculture, Pollinators

Canadian Wildlife Federation, Explore our Pollinators

Proceeding of the National Academy of Sciences of the United States of America, Non-bee insects are important contributors to global crop pollination, January 5, 2016

Xeres Society for Invertebrate Conservation, Who Are the Pollinators 

Alberta Institute for Wildlife Conservation, Alberta's Pollinators, May 1, 2018  

Let's talk science, Pollinators Are Important!, June 9, 2020 

United States Department of Agriculture, Animal Pollination

Nature Scape Alberta, Myrna Pearlman & Ted Pike, Red Deer River Naturalists and Federation of Alberta Naturalists