February 16, 2023
What’s a pollinator? Simply put, it is any animal that moves pollen from one plant to another.
And pollination is how plants produce fruit. Over 100 agricultural crop species in North America alone depend on pollinators for food production.
We are all very familiar with the honeybee, which is the most efficient pollinator in the insect world. You may have noticed large globs of yellow pollen on the hind legs of a honeybee worker as it returned to the hive. They have a specialized hind leg that contains hairs that serve as a pollen basket for transporting the pollen. They also have hairy bodies, which attracts pollen while they are foraging inside the flower for nectar.
However, a host of solitary ground- and wood-nesting bees and wasps live individually and help pollinate plants — and some of these insects are predators of pests. Other pollinators include bumblebees, flies, wasps, some beetles, and butterflies and moths. Additionally, bats and birds can spread pollen around. As these pollinators visit a given plant, the pollen on their bodies gets left behind, resulting in pollination. Pollination then leads to fruit and seed production, which completes the process of sexual reproduction in plants.
Like all living organisms, pollinators need a food source to enable them to fly and crawl, reproduce, and feed their young. Plant nectar provides energy, and in the case of honeybees, they also use pollen as a food source for raising immature bees. This is why providing a wide diversity of flowering plants from spring to fall is important.
On the land
For landowners, agroforestry and landscape practices such as windbreaks, riparian forest buffers, alley cropping and silvopasture can provide not only good food sources, but also pollinator habitat that can give pollinators a safe haven from predators and parasite-like insects that kill their host.
You may have heard of a human food desert. Pollinators can experience the same thing, if there are few flowering plants or very little plant diversity. We all like a varied diet and reliable supply of food, and pollinators are no different.
So what are some practical ways you can help pollinators? When selecting and positioning landscape or other plants, choose plants that will encourage visits by pollinators. For example, the common milkweed plant is the only host of the monarch butterfly, but may also be attractive to bees, wasps, flies and other beneficial critters.
Native plants are always a good choice. Besides being highly adapted to local weather and climate conditions, they are good sources of food and pollen for butterflies and bee species.
Timing of flowering is also important. Try to think in terms of a year-round bloom cycle. For example, goldenrod is a good fall species, and willow for winter and early spring. Many flowering fruit and landscape plants can be good sources in spring and summer, and milkweed is good for late summer and early fall.
Location is important. The less traveling for pollinators, the better. Moving from plant to plant costs insects valuable energy, and makes them potentially more vulnerable to predators and parasitoids. Pollen and nectar sources within about 750 feet of food crops like fruits and vegetables is best. We all like short commute times to the grocery store.
Finally, be very careful with pesticides. Unlike pests, pollinators are sensitive to chemicals and can be wiped out with just one careless application. Avoid planting pollinator plants near crop fields where sprays are common. If honeybee hives are close to regularly sprayed areas, by all means, let the beekeeper know and give them time to remove the hives, if necessary. No one wants their honeybees wiped out. Not only is it disastrous for the bees, but it may also be a person’s livelihood.
So, as you think about what plants to add to your landscape this spring, keep you friendly pollinators in mind. They work for free and are very effective. You will also benefit with higher yields and more productive food plants.
For more information on pollinators and habitat, consult the National Agroforestry Center.
Miller is a horticulture professor at Joliet Junior College in Joliet, Ill., and a senior research scientist in entomology at The Morton Arboretum in Lisle, Ill. Email your tree questions to him at [email protected].
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