Pollination results when the pollen from the male part of the flower (stamen) is moved to the female part of the same or another flower (stigma) and fertilizes it, resulting in the production of fruits and seeds. Some flowers rely on the wind to move pollen, while others rely on animals.
Animals visit flowers in search of food and sometimes even mates, shelter and nest-building materials. Some animals, such as many bees, intentionally collect pollen, while others, such as many butterflies and birds, move pollen incidentally because it sticks to their body while they are collecting nectar from the flowers. All of these animals are considered pollinators.
Pollinators are important. Imagine a world without fruits, vegetables or flowers. That’s what our world would be like without pollinators. Three-quarters of our flowering plants rely on insects, birds or bats to move pollen from the male to female parts of flowers for reproduction.
Without the assistance of pollinators, most plants cannot produce fruits and seeds. The fruits and seeds of flowering plants are an important food source for people and wildlife. Some of the seeds that are not eaten will eventually produce new plants, helping to maintain the plant population.
About 75 percent of flowering plants rely on animal pollinators for fertilization, and more than 200,000 species of animals act as pollinators. Of those, about 1,000 are hummingbirds, bats and small mammals, such as mice. The rest are insects, such as beetles, bees, ants, wasps, butterflies and moths.
Foods produced with the help of pollinators include apples, strawberries, blueberries, chocolate, melons, peaches, figs, tomatoes, pumpkins and almonds. In the United States, pollination by honeybees and other insects produces nearly $20 billion worth of products annually.
Worldwide, approximately 1,000 plants grown for food, beverages, fibers, spices and medicines need to be pollinated by animals to produce the resources on which we depend. We are not the only animal whose diets include animal-pollinated food. Many birds and mammals depend on fruits and berries for food.
Despite their importance to our economy and lives, many pollinators are in trouble.
The domesticated honeybee, (Apis mellifera), a nonnative bee raised specifically to pollinate crops, is declining. Causes include parasitic mites, disease, pesticide poisoning, encroachment of Africanized honeybees and a phenomenon, Colony Collapse Disorder, where worker bees leave the hive in search of nectar and do not return.
Many farmers depend on honeybees, leasing them during specific seasons to pollinate targeted crops. Declines in these managed pollinators can affect the availability, price and quality of the many fruits, vegetables and other products that depend on animal pollination.
The causes of decline in wild pollinators vary by species. Like the honeybee, the bumblebee has been hurt by the introduction of a nonnative parasite carried by bumblebees imported from Europe for greenhouse pollination.
Other pollinators have been affected by habitat loss or fragmentation. A healthy ecosystem provides pollinators with habitat for foraging, nesting, roosting and mating. Homes, businesses and roads are replacing the native fields, wetlands and forests that are home to many pollinators. In addition, many of the wildflowers used by pollinators for food, nesting or egg-laying are rapidly disappearing.
Migrating pollinators such as bats, butterflies and hummingbirds face even more problems. These travelers need nectar-producing flowers all along their journeys. But wildflowers and natural habitats are being replaced by development. The identification and protection of nectar corridors is important for the survival of these pollinators as they migrate.
Pesticides are also a threat. Many pesticides used on farms and backyard gardens are broad-spectrum types, meaning they can harm non-target species too. Insecticides that get rid of plant pests can also be toxic to bees and other beneficial insects.
Bees recover slowly from insecticide spraying and other disturbances because of their low fecundity — they are unable to reproduce rapidly or in great numbers. It may take three to four years for bumblebee populations to return to their pre-pesticide application numbers.
Here are ways that you can help:
- Plant gardens filled with native, nectar-producing flowers for your area. Go to http://pollinator.org/guides.htm and type in your zip code. You’ll get information about pollinators in your area plus a list of the plants they use. People can also download a free app to get this same information on their smart phone.
- Avoid or limit the use of pesticides. or, if possible, stop using them altogether. If you must use an insecticide, choose one that is the least toxic to nonpest species and does not persist on vegetation.
- Leave tree stumps, dead branches and rotting trees on your property, if possible. They provide nests for some bee species.
- If there is 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.
Pollinator Week is June 18–24, 2012. Go to www.pollinator.org for details on events, activities and resources.
For educational resources about pollinators, visit www.fws.gov/pollinators/
To read or download a copy of the National Academy of Sciences report, “Status of Pollinators in North America,” go to http://dels.nas.edu/pollinators/