One out of every three bites of food we take comes to us because of animal pollinators. Thanks to a complex assortment of bees, flies and other insects, as well as bats and occasionally other mammals, our markets offer pumpkins, apples, blueberries (and dozens of other pollinator-dependent fruits), and products like sunflower and canola oil. Without these hard-working animals, much of the variety in our diets would be lost.
Take chocolate, for example. Thankfully for chocolate lovers, this delicacy is now on the “good” list as far as nutrition experts are concerned. Chocolate is rich in flavonoids, a group of compounds with antioxidant properties that are now linked to cardiovascular health. Some experts recommend the consumption of as much as three ounces of dark chocolate daily. Without a group of quiet but essential pollinators, however, chocolate would cease to exist.
For decades, scientists debated which insects played a role in the pollination of chocolate. Recent research now points to a tiny midge, believed to be the only insect that can successfully work its way into the complex cacao flower to allow for pollination. Without this midge, pollination would not occur, and the cacao fruit would never develop.
Like the cacao plant, the midge pollinator is native to South American tropical rain forests, but the insect is not always abundant on cacao plantations. These insects require humid shade and a mixture of moist debris on the forest floor, conditions not always met in larger, more open plantations. As rain forest areas are destroyed, so is the natural habitat of this midge.
Because small cacao plantations closer to the rain forest have better rates of pollination, experts are looking to preserve chocolate, small farms, the rain forest and midge pollinators, all at the same time, through habitat development in small areas. Grow cacao more closely to the way it evolved — as one component of a rainforest ecosystem — and everybody wins.
This close relationship of pollinators, plants and habitat isn’t just a rain forest issue. Here in North America, our native pollinators are also at risk, due to pests and pathogens, habitat loss and degradation, and pesticide use.
This issue has gained more attention in the last decade since significant pest problems have virtually eliminated wild honey bee hives. Honey bees are not native to North America; they were brought here by settlers but were able to establish themselves in natural areas until the introduction of mite pests. These destructive mites can be dealt with by beekeepers tending managed hives, but have all but eliminated honey bees in the wild.
The decline of honey bee pollinators has brought home, quite literally, the importance of native bees as pollinators. Orchard owners and vegetable farmers are looking to native bees to ensure proper pollination of their crops as honey bee numbers decline.
Bumble bees, carpenter bees, mason bees, sweat bees and hundreds of other small and large bees play an important role as pollinators. These bees have hairy legs or abdomens, perfect for transporting pollen from flower to flower. These bees visit flowers to gather nectar and pollen, the food source fed to bee offspring. Pollen grains stick to the bees’ bodies, and are transported from flower to flower.
So what is pollination, exactly? Pollination is the transfer of pollen from the male portion, or stamen, of one flower to the female portion, or pistil, of another flower. Once the pollen reaches a receptive flower, it grows down through the flower to fertilize the ovules, thereby creating seeds and prompting the development of fruit.
Many flowers are self-sterile, meaning they need the pollen from a different flower (and sometimes a different plant) for pollination to occur. Fruit doesn’t set without pollination; without full pollination, fruit will be lumpy or misshapen.
Since plants can’t move, they need help transferring this pollen from flower to flower. Some plants have evolved to shed large amounts of pollen on the wind; with so much pollen flying around, some is bound to find its way to the female flower.
Other plants have evolved along with animal pollinators, offering their helpers energy- and protein-rich nectar and pollen as enticements to visit. In the process of visiting many flowers of the same type, these pollinators take along some pollen to receptive female flowers, thus helping to ensure the next generation of plants.
Everyone’s garden can be pollinator-friendly, providing an oasis for native pollinators as they go about their work. By providing plants, shelter, water and a friendly environment for pollinators, gardeners can create habitat links that otherwise might be missing. To create a pollinator-friendly garden, consider the following practices:
• Create foraging habitat by including plants in the landscape that flower from spring through fall.
A consistent diet of nectar and pollen throughout the season helps to ensure plenty of offspring and a healthy breeding population for next year. Favorite bee plants include many popular sun-loving perennials, such as bee balm, purple coneflower, thyme, catmint, mint, hyssop and asters.
Annuals such as sunflowers, zinnia and calendula are also attractive to bees. Watch the garden, and let the bees tell you which plants they prefer.
• Create nesting habitats for solitary bees such as mason bees.
These gentle bees are extremely efficient pollinators, and they will move into created nests. Find information on building habitat at the Xerces Society for Invertebrate Conservation website (www.xerces.org).
• Reduce or eliminate pesticide use.
When selecting pesticides, make choices that have the least impact on pollinators. Insecticidal soaps and horticultural oils are good choices, because they don’t leave a residue on plants that can kill pollinators.
Dusts are the most harmful to pollinators because the poison sticks to their bodies like pollen. Keep in mind that fungicides, herbicides and other pesticides can harm bees, not just insecticides.
• Learn more about the plight of pollinators.
The Xerces Society and the Pollinator Partnership (www.pollinator.org) are two organizations committed to preserving pollinator populations.
Many excellent books have been published on pollinator conservation. Look for Attracting Native Pollinators, published by the Xerces Society, and The Forgotten Pollinators, by Stephen Buchmann and Gary Paul Nabhan.
Denise Ellsworth directs the honeybee and native pollinator education program for the Ohio State University. If you have questions about caring for your garden, contact her at 330-263-3700 or click on the Ask Denise link on her blog at www.osugarden.com.