Beyond honey bees: Seeking alternative pollinators
Print
EmailSome plants require specialists to help in the pollination process
While many of us spend time looking for pest insects in our gardens, we should also be looking for beneficial insects. Among beneficial insects are those that help pollinate flowers, including the flowers that grow into fruits and vegetables. Most plants cannot pollinate themselves; pollen grains must be carried from flower to flower of the same species in some way, through wind, water, animals or insects. Bees are some of our most efficient pollinator insects and are essential to sustaining life on earth. As populations of insects decline, it is important that we find ways to attract and retain native pollinators in our gardens.
European honey bees (Apis mellifera) are helpful pollinators in many crops, but not all crops are easily pollinated by honey bees. Some plants such as blueberries and tomatoes need pollinators that can “buzz” the flower, shaking the pollen loose rather than go in to collect it. Native bumble bees are better at this than honey bees, making them valuable for setting fruit in these crops. Other plants might depend solely on flies to pollinate, such as the pawpaw (Asimina triloba).
To bring alternative pollinators to your yard or garden, Michigan State University Extension recommends creating gardens or spaces that provide habitat for native pollinators. This will invite them to visit, pollinate flowers, make nests and reproduce nearby. There are generalist bees that live in Michigan that switch easily between fruit and vegetable crops, non-native flower gardens and native plants. Other bees are specialists and require specific plants to survive. One example in Michigan is Melissodes denticulatus, the denticulate long-horned bee that only feeds its larvae pollen from ironweed (Vernonia) species.
It is easy to attract and support bees with native plants and other flowers that are selected to bloom at a variety of times throughout the growing season.
Other organisms not generally thought of as pollinators are butterflies, wasps, beetles and hummingbirds. Some of these even look like bees! While these animals are not the best at pollination, they do contribute to the process. Some are specialists, for example the goldenrod soldier beetle frequently visits and pollinates goldenrod species (Solidago) and yarrow (Achillea).
Non-bee pollinators are just as important as bees because they may be the only animal that is active during the plant’s blooming time. They may also be able to reach pollen in flowers that are difficult for others to access. Carrion feeding flies and beetles pollinate skunk cabbage (Symplocarpus foetidus) when it blooms while snow is still on the ground in Michigan.
The difference in the size, shape or color of the flower determines which pollinators can access it for nourishment. Long, narrow flowers require organisms with long tongues or proboscis. Smaller, delicate flowers require short tongues or proboscis or a smaller bodied insect like a sweat bee or a hover fly. Some flowers have evolved to accommodate hummingbirds, like Cardinal flower (Lobelia cardinalis), while others require the weight of a bumble bee to open them enough to expose the pollen for collecting. The flowers of bottle gentian (Gentiana andrewsii) never fully open and need the weight and strength of a sturdy bumble bee to climb inside to access nutrition, inadvertently cover itself in pollen, and then fly to another bottle gentian nearby and spread the genetic material. Any animal that visits a flower for its nectar or pollen is a potential pollinator.
Supporting a diverse ecosystem is the best way to promote pollination by a variety of species. You can help increase populations of alternative pollinators by planting native plants and reducing or eliminating pesticide usage. Targeting only pest species when they are present and active is key to reducing pesticides. You can identify plants and pests correctly by submitting photos and asking for advice to Ask Extension.
Follow pesticide label directions—the label is the law, and more is not better. Do not use pesticides near your native plant gardens. Also, consider creating more wild spaces on your property to encourage alternative pollinators to visit.
Get outside, look closely, and pay attention to fully appreciate the diversity of pollinators in your own backyard.
For more information, visit the Gardening in Michigan website.
This work is supported by the Crop Protection and Pest Management Program (grant no 2024-70006-43569) from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.
