Many people do not realize that native bees have been pollinating the continent’s flowering plants long before honey bees were brought from Europe.
As bees move from flower to flower collecting nectar, they also move pollen from flower to flower. Pollination occurs when pollen grains from a flower’s male parts (anthers) are moved to the female part (stigma). Once on the stigma, the pollen grain grows a tube that runs down into the ovary, where fertilization occurs.
Bees, both honey bees and native bees, are crucial to the production of most fruits, nuts and berries on which people and wildlife depend.
Although honey bees are used extensively in agriculture, many plants still rely on native bees for pollination. Many of the common dishes we relish on Thanksgiving might not be on the table without native bees: apple pie, pumpkin pie, cranberries, the onions in stuffing, as well as many vegetables like carrots, sweet potatoes, squash, brussels sprouts, broccoli and green beans. Even the almonds for tasty casseroles would be missing.
For instance, the honey bee does not know how to pollinate tomato or eggplant flowers. And, it does very poorly compared with native bees when it comes to pollinating many native plants, including pumpkins, cherries, blueberries and cranberries.
Some native bees, like bumblebees, are generalists, and gather pollen from a wide variety of flowering plants. They use a method called buzz pollination, in which a bee attaches itself to a flower and rapidly vibrates its flight muscles. This causes the entire flower to vibrate and loosens the pollen so it flows out of the openings in the anthers.
Plants that rely on buzz pollination include tomatoes, cranberries, blueberries and eggplants. The bumblebee is also an important pollinator of some clovers, a forage crop for cattle.
Other native bees are specialists, requiring certain plant species. Squash bees, for example, are very efficient pollinators of melons and various squashes, including zucchini and pumpkin. These bees often nest underground beneath the plants they will pollinate. So if you go to a local pumpkin patch around Halloween, it’s likely that you are walking over nests full of developing young squash bees.
Blueberry bees and cactus bees are also specialists. Miner bees nest underground and are very good pollinators of apple species.
Some bee species are only active for a few weeks during the growing season and depend on plants that flower at that same time.
Many pollinators — so important to our economy and lives — are in trouble. Honeybees, raised specifically to pollinate crops, are declining. Causes include parasitic mites, disease, pesticide poisoning, the encroachment of Africanized honey bees and a phenomenon, Colony Collapse Disorder (CCD), where they leave the hive in search of nectar and do not return.
The causes of decline in wild bee populations vary by species. Like the honey bee, the bumblebee has been hurt by the introduction of a nonnative parasite carried by bumblebees imported from Europe for greenhouse pollination.
Pesticides are also a threat. Many of the pesticides used on farms and backyard gardens are broad-spectrum varieties, meaning that not only are they toxic to plant pests, but bees and other beneficial insects as well.
The loss of habitats and native plants affects native bees and other insect pollinators including butterflies.
To help conserve native bees and other pollinators:
- Reduce the use of pesticides. If you must use an insecticide, apply it in the evening when many pollinators are inactive. If possible, stop using pesticides altogether.
- Plant gardens filled with native, nectar-producing flowers for your area. Go to pollinator.org/guides.htm and type in your zip code. You’ll get information about pollinators in your area plus a list of pollinator plants.
- Leave tree stumps, dead branches and rotting trees on your property, if possible. They provide nests for some species of bees.
- If you find a bee nest too close to your home, don’t destroy it. Contact a local beekeeper or your state cooperative extension service for advice about removing the nest without harming the bees.