Gardening Columns

The 2007 pollinator postage stamps were unveiled at the Pollinator
Partnership Symposium in Washington, D.C. last week.

Paean to Pollinators

First published on garden.org on October 23, 2006, by Suzanne DeJohn

African lions, Siberian tigers, orca whales, great white sharks, grizzly bears -- Conservationists sometimes refer to these as "charismatic megafauna." Megafauna because they're big (mega) animals (fauna), and charismatic because they grab the public's interest and are used as poster children to make the case for conserving natural areas. However, each of these would, if given the chance, probably eat you alive. Let's look at another class of creatures that plays a far greater and more beneficent role in our everyday life, yet generally receives much less attention: the microfauna that pollinates our plants.

Last week, the North American Pollination Protection Campaign (NAPPC) held its annual conference, during which organizers annouced that the U.S. Senate recently passed a resolution designating June 24-30, 2007, as National Pollinator Week. They also unveiled the design for the 2007 U.S. Postal Service postage stamps honoring pollinators.

Why should we care about pollinators? According to the NAPPC Web site (www.pollinator.org), "Pollinators, almost all of which are insects, are indispensable partners for an estimated 1 out of every 3 mouthfuls of food, spices and condiments we eat, and the beverages we drink. They are essential to the fibers we use, the medicines that keep us healthy, and more than half of the world's diet of fats and oils." Don't these diminutive denizens deserve at least as much attention as a whale?

What Is Pollination?
In case you've forgotten your botany, pollination is the act of transferring pollen from anther to stigma, either within a single flower or from one flower to another. Once it is transferred to the stigma, the pollen germinates, the sperm it contains is delivered to the egg, and fertilization occurs. In some plants (most notably grasses, including corn), wind accomplishes this task. But many plants rely on insects or animals to transfer the pollen.

Without pollination, there is no fertilization and no viable seed production. And no fruit. Without pollination, there'd be no apples, melons, pumpkins, tomatoes, beans, or blueberries. And no walnuts, cashews, or peanuts, either.

Some of these, such as melons and pumpkins, require a pollinator to transfer the pollen from flower to flower. Others, such as tomatoes and peanuts, are self-fertile -- for example, the pollen may simply drop from the anther to the stigma within a flower. But most plants produce better fruit if fertilized with pollen from another plant, and all plants benefit from the transfer of pollen from one plant to another because it increases the genetic diversity of the species.

Who Are the Pollinators?
Honey bees are the most well known of the pollinators, but there are hundreds, if not thousands, of species that perform the task. From the ubiquitous little sweat bees to the exotic nectar bats, these creatures transfer pollen inadvertently while they are gathering nectar or pollen for food. Nectar is, in fact, an adaptation that plants evolved to lure pollinators to visit the flowers, encourage them to visit similar flowers, and in the process transfer pollen from flower to flower within a species.

Attracting Pollinators to Your Garden
The NAPPC Web site suggests 10 plants that are attractive, widely available, and good food sources for pollinators. They are yarrow sage, milkweeds, coneflowers, penstemons, verbena, fruit trees, lupines, willows, and mallows. Other good plants are dill, parsley, fennel, coreopsis, cosmos, sunflowers, black-eyed Susans, zinnias, and phlox. In planning your garden, choose a variety of plants that bloom at different times, so something is in bloom all summer long. Native plants are ideal because they coevolved with native pollinators. Hybrids, especially those with double flowers, may not produce much nectar, so stick with species or single flowers.

In addition to food, you can create an inviting habitat by planting a windbreak, adding rocks as warm spots for insects to sun themselves, and providing a muddy spot for butterflies to drink and get the minerals they need.

Avoid spraying insecticides, or any pesticide for that matter. Remember that caterpillars are butterfly larvae, so learn to recognize them by species. Even some organic insecticides are non-selective, meaning they kill all caterpillars, not just the pests.

But Are They Charismatic?
Speaking of habitat, it's relatively easy to raise money to save cute and cuddly-looking giant pandas. Can we say the same for these industrious little pollinators?

Like beauty, charisma is in the eyes of the beholder. Consider the butterfly. What other organism offers such a range of coloration and undergoes such a transformation? What's more, the monarch butterfly travels thousands of miles to overwinter in Mexico. Then its offspring somehow know to fly north. And their offspring fly back south, to the exact same overwintering spot as their grandparents. Charismatic as it might be, can a panda do that?

And how about that honey bee. Upon returning to the hive after foraging, a worker bee performs an elaborate "waggle dance" to describe to her coworkers the position of a nectar or pollen source. With the precision of a tango, the bee "waggles her body from side to side as she moves forward in a straight line, then circles to the right, back to her starting point, waggles ahead again, and then circles to the left ... The angle of the straight run, or 'waggle,' from vertical is equal to the angle from the hive between the sun and the nectar/pollen source." (Source: Michigan Entomological Society) I'd say this bee jitterbug counts for something in the charisma department!

Let's all do our best to welcome and protect pollinators, large and small, and remember how vital they are to our very existence. With one out of every three mouthfuls of our food depending on them, it's the least we can do.