Stories about the decline and disappearance of pollinators are abundant in the news worldwide and there’s no doubt that these stories are spurring action in our communities.
But what exactly is pollination, who are the pollinators, and why are they important?
What is pollination?
Pollination is the act of pollen being moved from the anther of a flower to the stigma in order for that plant to reproduce. This can happen in two ways:
1. Self pollination – The pollen comes from the same flower, or from another flower on the same plant. Few plants are pollinated this way, but it can occur as pollen is shed directly onto the stigma, or as the flower closes.
2. Cross pollination – Pollen comes from another plant. Since plants can’t move, this requires the help of pollen “vectors”. Pollen vectors are the ways by which pollen is transferred from flower to flower, and can include: wind and animals, including insects. Wind pollination comes with a low success rate, so it’s much more effective for plants to entice animals, particularly insects, to visit the flower and move pollen specifically from flower to flower. It is estimated that approximately 65% of plants depend on insects as pollinators, and insects make up the most effective group of pollinators.
Why are pollinators important?
Why should we care about pollinators? For one, they provide the vast majority of animal life (including humans) with food. Up to 1/3 of the food you eat exists because of the daily actions of pollinators smaller than the size of your thumbnail! They are important because they form a huge part of the foundation of the food chain. A healthy, diverse habitat with lots of pollinators and other insects is a healthy place for other wildlife. Many plants in turn depend on pollinators for their existence.
Meet the pollinators!
Bees are one of the earliest pollinators to show up in the spring and are by far the most effective pollinators because of their long tongues, hairy bodies, and affinity to bloom periods. Honey bees are one of the most well-known species in Ontario, but it should be noted that honey bees are actually a non-native species, introduced to North America when settlers arrived from Europe. While honey bees are definitely important pollinators and we depend on them to pollinate many of our agricultural crops across the continent, the importance of our native bees as pollinators should not go overlooked. Unfortunately many of our native bee populations are in steep decline, putting vegetable production in jeopardy. For example, tomato greenhouses heavily depend on bumble bee pollination, and squash farmers rely on squash bees to pollinate their crops. Declines in the pollination of these two bees jeopardizes tomato and squash production.
Many people don’t realize how important flies are in the pollination process! In the tropics, a species of midge fly pollinates the cacao plant – no fly, no chocolate! In Canada, they are important to early-spring flowers when few insects are active. Flies are also beneficial in the garden for pest control. The larvae of flower flies predate on aphids meaning, less unwanted insects in your garden!
There are many flies that mimic bees and wasps, and they can be very difficult to tell apart! If you’re close enough to examine it, flies have only one pair of wings while bees and wasps have two pairs of wings. Flies’ eyes are often quite large and touching in the middle and their antennae arise from a single point between them. Bees and wasps have smaller eyes that often don’t touch, and their antennae arise from two separate points.
Some beetles feed on protein-rich pollen from flowers, and transfer the pollen around as they visit multiple flowers for food. As pollinators they are not quite as effective as bees, but we have many beetle species in Ontario that are important pollinators for wildflowers such as Goldenrod and Queen Anne’s Lace.
Note: Ladybugs are beetles but not pollinators! However, they are beneficial to have in your garden because they prey upon aphids, which are not always a welcome visitor in a garden.
Insects are the primary players when it comes to the pollination game, but some birds can help to transmit pollen as well. Hummingbirds are birds with a sweet tooth, seeking out nectar from flowering plants and shrubs. Sometimes pollen can become attached to their bill or breast feathers and be carried to the next plant. The Ruby-Throated hummingbird is the only species seen in southern Ontario. Males have a ruby red throat (which can also appear black depending on the angle of light) and females have a pale white throat (pictured above).
Moths are not that different from butterflies! Since most moths fly at night, they play an important role in pollinating night- and dusk-blooming plants. There are exceptions, like the Virginia Ctenucha (often pronounced “Tenooka”) – this is a day-flying moth that is often mistaken for a butterfly. Like butterflies, moths travel greater distances than bees and visit a greater number of blooms.
Due to their day-flying habits and their showy colours, butterflies tend to be more well-known than moths. Though butterflies are less efficient than bees at moving pollen between plants because they have long legs that lack the specialized structures for collecting it, but they visit a vast number of flowers each day because they travel greater distances.