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Saving Pollinators
by Alison Emblidge and Emily Schuster

Among the tall tualang trees of the Malaysian rainforest, the sultan’s son and a Hindu handmaiden fell in love. The beautiful handmaiden’s name was Hitam Manis, meaning "dark sweetness," but she was a commoner and could not marry the prince. The sultan, angered that his heir would court outside the royal sphere, stabbed Hitam Manis through the heart. She and her fellow handmaidens turned into bees and flew into the forest.

Later, the prince climbed a tualang tree with a knife and pail in pursuit of a tempting honeycomb. When the bucket was lowered, the servants found not a sweet treasure, but their prince’s body in pieces. The prince had desecrated the hive with his metal knife, similar to the weapon that had killed Hitam Manis.

--From the Rig-Veda, a book of Hindu hymns, second millenium B.C.

Malaysian honey hunters work precariously in the rainforest canopy with ritual and respect. They hunt only with wood, hide, or cow bone tools—never metal knives—in deference to Hitam Manis, and sometimes call the bees by her name. In turn, the honey hunters are rewarded with a good income and confidence the giant bees will return to their nests after harvest. The men respect the bees because their livelihood depends on it.

We should all respect bees, however, as we depend on them and other pollinators for much of our food. Imagine a world with no bananas or beans, no lettuce or almonds, no tomatoes or cucumbers. Imagine no jack-o-lanterns at Halloween or hot sauce on your burrito, no chocolate chips, strawberry yogurt, or morning cup of coffee. These and countless crops, from onions and carrots to sunflowers and cinnamon, rely on wild insects for reproduction. One hundred thirty U.S. crops are insect pollinated, and the value of pollination to U.S. agriculture is estimated at $40 billion per year, when livestock feed crops are included. Worldwide, pollinators are worth $200 billion annually.

Pollinators are critical to much more than what fills our stomachs. The loss of a pollinator could cause the collapse of an ecosystem. In some tropical communities, for instance, figs support as much as 80 percent of vertebrates. In the western United States, rufous hummingbirds pollinate wildflowers that help recolonize deforested areas and prevent erosion, according to William Calder, ecologist at the University of Arizona-Tucson. Bats are essential pollinators of trees that support many species in Samoa’s rainforest canopy. Low bush blueberries sustain populations of birds and black bears in the North American Arctic. In short, pollinators support life around the world.

Unfortunately, pollinator populations are now declining worldwide. More than half of the managed honeybee colonies in the United States have been lost in the last 50 years, and 25 percent of this loss has occurred within the last five, according to Amos S. Eno, Executive Director of the National Fish and Wildlife Foundation. This, of course, means trouble for the honey industry, but the pollination services provided by honeybees are worth 50 to 60 times more than the value of the honey and wax they produce. And as far as threats to pollination goes, the trouble with bees is just the beginning. "Bees are the canaries in the coal mine," entomologist Stephen Buchmann of the University of Arizona-Tucson said—an alarm signal indicating even more danger. Nearly 200 species of wild vertebrate pollinators are threatened with extinction, according to Gabriela Chavarria of the National Fish and Wildlife Foundation. More than 218,000 out of the 250,000 total species of flowering plants rely on pollinators for survival, but populations of pollinators, including insects, birds, and bats, are dwindling.

Pollinator loss jeopardizes the survival of flowering plants and the elegant biological systems they support. Although most animals have the luxury of walking, swimming, or flying to find their mates, plants, generally stuck in one place for life, have to be a bit more creative. Although wind and water serve to transport some flowering plants’ pollen grains, 91 percent of all flowering plants depend on animal pollinators in order to make seeds. These pollinators, including insects and vertebrates, enter flowers to search for nectar, shelter, oils, or perfumes, and leave with pollen stuck on their bodies. As they move from flower to flower, they carry pollen from stamens, the male flower parts, to pistils, the female flower parts. When egg and sperm combine, seeds are produced. By transporting pollen between flowers that are relatively far apart, pollinators help maintain genetic diversity within plants and prevent problems associated with inbreeding. Because both the plant and the pollinator benefit from the interaction, it is called a mutualistic relationship.

With 130,000 to 200,000 species of pollinators, a "typical" pollinator doesn’t exist. Beetles, which make up 350,000 named species worldwide, pollinate about 88 percent of all flowering plants, also called angiosperms. Ants, wasps, and bees collectively pollinate 18 percent. Butterflies and moths pollinate eight percent of all angiosperms. Although birds and bats and other mammals don’t pollinate many species, they are vital for the plants that rely on them for reproduction. Bats alone bring us many products, including vanilla, dates, tequila, and bananas.

Plants and pollinators have been evolving together since at least the early Cretaceous period—that’s 144 million years and more than a billion bee generations—and their relationships have become increasingly specialized. Flower color, shape, fragrance, and position attract specific pollinators. For some flowers, timing is everything. Yellow lantana flowers turn red—a shade that is invisible to butterflies—once they are pollinated in order to concentrate butterfly activity on unpollinated yellow flowers. Scarlet gilia flowers attract hummingbirds with red flowers in early summer and switch to white during late summer in order to attract nocturnal hawkmoths. Pollinators, in turn, sometimes seek very specific commodities from plants. Males of one butterfly species visit flowers to collect certain alkaloids, a butterfly aphrodisiac of sorts that sends females of the species into a narcotic swoon. When the butterflies mate, the male transfers the chemical to the female’s reproductive tract and she coats her eggs with it to protect them from ant attacks, according to Adrian Forsyth, an entomologist with the Smithsonian National Museum of Natural History.

Although specialization increases pollinator efficiency, an inherent problem lurks. "Each of the mutualists suffers reproductive failure when the other cannot be found at the right place at the right time," wrote University of Arizona’s Buchmann and Gary Nabhan, Director of Science at the Arizona-Sonora Desert Museum, in their book, The Forgotten Pollinators. It makes sense, then, that fewer than one percent of plants rely exclusively on a specific pollinators species, and vice versa. In Madagascar, for example, only the black-and-white ruffed lemur is agile enough to open and pollinate the traveler’s tree flowers. Without the lemur, the trees couldn’t reproduce. But even those species involved in many different mutualistic relationships are vulnerable. Habitat loss, fragmentation, pesticides, and exotic species all jeopardize plant/pollinator relationships.

Some pollinators depend on a series of plant species to sustain them throughout the year, and the absence of just one plant species in the series could mean starvation. Similarly, migratory pollinators all over the world frequently follow "nectar corridors" on their annual journeys, requiring a flower to bloom in perfect synchrony with the time the pollinator passes over. Some corridors have been fragmented, altered, or destroyed over stretches of 20 to 60 miles, longer than some pollinators can fly in a day, according to Nabhan and Ted Fleming of the University of Miami. In Sonora, Mexico, nectar corridors fell victim to invasion by more than 400,000 square miles of buffel grass, an exotic African species planted as feed for cattle. Such destruction of nectar corridors not only reduces the total nectar sources available to the pollinator, but, Nabhan postulates, it might force a migrating pollinator to rush through a barren area of a nectar corridor and arrive at the next spot before its flowers are in bloom, throwing the entire system out of synch.

Logging and farming often leave pollinators homeless. Due to severe habitat loss, migratory monarch butterflies now have only a few overwintering sites in Mexico and California that meet their very specific needs: abundant nectar and water sources and a forest canopy that lets in just the right amount of light, for example. With so few sites remaining, an isolated event at a single site—habitat destruction or even an unexpected bout of bad weather—can mean big trouble for the entire species. For example, one-third of all monarchs aggregating in the Michoacan in Mexico were killed in a recent blizzard. If the monarchs had been dispersed over many sites, the blizzard would not have been such a major blow to the world’s monarch population. Some farming methods also threaten pollinators by destroying their habitats. Large-scale modern agricultural operations produce extensive fields of a single crop, and when the crop’s short season is over, nothing remains for bees to eat. Extensive irrigation also destroys solitary bees’ underground nests and increases the damage that fungi do to their broods.

Habitat fragmentation can be equally harmful to pollinators. Tallgrass prairie in Iowa that once sprawled across five million acres is now reduced to only 200 acres, some of it in isolated fragments too small and too far apart to support pollinator populations. In Peru, 50 percent of the economy depends on Brazil nuts, an entirely wild commodity that cannot be grown in plantations because of the plant’s dependence on orchid bees for pollination. Realizing the importance of the crop, Peru passed laws to protect Brazil nut trees, but failed to protect the surrounding forest as well. This led to a highly dysfunctional ecosystem consisting of isolated Brazil nut trees surrounded by pasture. Without the forest, orchid bees could not survive to pollinate the trees. The decline of the Brazil nut has implications for more than Peru’s economy, as the Brazil nut tree is a key player in its ecosystem. In a healthy ecosystem, when the trees’ seed pods of nuts open, they fill with water and become home to mosquito larvae, toad tadpoles, damselfly larvae, and dart poison frog tadpoles.

The term "habitat fragmentation" conjures up images of a few wild areas separated by ecowastelands: housing developments, pastures, deforested regions. But another type of fragmentation, chemical fragmentation, is less obvious and equally harmful. For example, when a crop is sprayed with pesticides, the chemicals infect the surrounding soil and water, killing pollinator species and their larvae. The pollinators survive outside the sprayed areas, but because they cannot cross into the poisoned cropland, the land might as well be a concrete parking garage.

When asked what is the biggest threat to bees in the D.C. area, entomologist Suzanne W. T. Batra of the United States Department of Agriculture (USDA) replied, "Pesticides, pesticides, pesticides." According to Cornell University entomologist David Pimentel, U.S. farmers use 700 million pounds of pesticides annually— 33 times more than at the beginning of the century. Insecticide use is up ten-fold. Despite these increases, crop losses to insects have risen from seven percent annually in 1945 to about 13 percent today, Pimentel said. Pesticides frequently drift from crop fields into adjacent wild lands, destroying helpful pollinators along with harmful pests. Fifty to 75 percent of pesticides sprayed by aircraft can miss their mark, according to Pimentel and associates. Misuse of pesticides is rampant—according to a 1994 survey by the Arizona Toxics Information Director Michael Gregory and associates, only one in 48 Mexican farmworkers had been taught how to apply pesticides effectively.

Invasion by exotic pollinators is another danger to native pollinators. Africanized honeybees, which first colonized the United States in 1990 after their accidental release in Brazil some 30 years earlier, will likely become a dominant pollinator in the southern United States, and may expand further north. Because they actively seek food for short periods of a few hours or days, Africanized honeybees quickly exploit food resources and threaten to outcompete European honeybees and other bees as well. Africanized honeybees develop faster than the European variety, allowing them to produce more bees more quickly. They travel quickly, too, often abandoning their hives and sometimes traveling up to 100 miles before choosing a new place to nest. Africanized honeybees cannot be easily managed because they are particularly defensive, tending to respond to threats to their colonies more quickly, more aggressively, and in larger numbers than European honeybees.

The familiar European honeybee itself is an exotic animal in the United States, introduced by 17th-century colonists. European honeybees now compete with many other bees for resources. In North America alone, there are more than 3,500 species of bees, most of them ground-nesting and solitary. Although honeybees are generalists that can pollinate a wide variety of plants, they are rarely as efficient as other pollinators that are better adapted for the job. Also, because honeybees visit a variety of flowers, there is less chance that the pollen they collect will reach a flower of the right species. The fact that the honeybee has outcompeted native bees in many areas is proving to be troublesome, especially now that honeybees are declining themselves, a result of parasitic mites, harsh winters, pesticides, herbicides, disease, and competition from Africanized honeybees. According to a study by bee biologist Edward Southwick and economist Lawrence Southwick, honeybee loss will cost the United States up to $5.7 billion per year if other pollinators are unable to pick up the slack. And according to Buchmann, 70 to 90 percent of wild bees have been lost in many states.

With so many threats facing such an important biological function as pollination, action must be taken quickly. "There are a sufficient number of hotspots [in pollinator populations]," said Peter Kevan, professor of environmental biology at the University of Guelph, Ontario, "and if we don’t pay attention to them, we’ll be in trouble."

Of all the dangers facing pollinators today, perhaps the biggest and most all-encompassing one is human ignorance. To combat this, National Fish and Wildlife Foundation’s Chavarria organized a symposium entitled "Saving America’s Pollinators," which was held at the Smithsonian National Zoo in mid-1998. Chavarria became interested in pollination because, as she put it, "We eat." She organized the symposium to educate others about the vital role pollinators play in our lives. Presented in partnership with San Francisco’s Butterfly Discovery Park and in cooperation with the U.S. Forest Service, the Bureau of Land Management, and the U.S. Fish and Wildlife Service, the symposium targeted federal agencies, policy-makers, and foundations that have influence over wildlife and ecosystems. Speakers again and again emphasized the need for more research, education, and publicity about the pollinator decline. Chavarria expressed her hope that the symposium would increase awareness among those in the position to make a difference, and said she plans to reach out to the general public in a similar forum in the future. "Learning about pollination is the first step," she said.

In a recent paper commissioned by the Society for Conservation Biology, 22 experts outlined a plan for pollinator conservation. They emphasized the need for more research—to monitor the declines and discover what is causing them before developing plans for preserving and restoring pollinators, plants, and habitats. They also stress general education—they would like to see students learning about the importance of pollination early on, and want better warning labels on pesticides and more thorough training programs for those who use them. They also hope that people who manage land—like open space on or near farms, state highways, parks, railroads, golf courses, gardens, and arboreta—will plant nectar-rich species to support pollinator populations.

The University of Guelph’s Kevan stresses three important concepts: species, spaces, and systems. We need to focus conservation efforts not just on species, but also on the spaces they inhabit, and devote time and energy to understanding how ecological systems operate. For example, Kevan disagrees with attempts to save honeybees by developing mite repellents because this approach focuses on one species, not spaces and systems. Kevan says that a variety of pollinators working one crop enhances the number and the quality of fruit produced. "There is a crying need to diversify ‘domesticated’ pollinators," he said. The Forgotten Pollinators Campaign of the Arizona-Sonora Desert Museum also recommends combating the effects of the European honeybee decline by investing in alternative pollinators, both wild and managed, including alfalfa leafcutter bees, alkali bees, bumblebees, mason bees, and blue orchid bees.

Unfortunately, putting theory into practice is not simple. A huge obstacle to conserving pollinators is "a lack of modest funding," according to Kevan. He estimates that about $25,000 per year could keep the Forgotten Pollinators Campaign moving, but more is needed for necessary research. Funding is also problematic in implementing conservation practices. As Eric Lawton of the Bureau of Land Management pointed out, agencies make decisions that they can afford, whether or not those decisions are the best ones for wildlife.

Farmers also make decisions that they think they can afford. Many farmers are reluctant to change over to organic farming because they believe it will increase expenses, decrease crop yields, and shrink their markets. But Nabhan stated that farmers are not enemies of conservation because their livelihood depends on sound ecological (and economical) management. Pesticides cost money and if they aren’t needed, farmers won’t pay for them, said Janet Anderson of the Environmental Protection Agency. Pimentel believes that "farmers are reluctant to lower pesticide use because of the advice that they get. Many non-chemical controls are available for farmers but they need sound advice on how to use these." Furthermore, as organic goods become increasingly popular, consumer demand encourages farmers to reduce pesticide use.

But according to the EPA’s Anderson, "There are not enough biological pesticides to replace all the chemical pesticides and using them often requires a different set of skills and equipment." In California, pear growers are trying to use fewer chemicals, but it does not take an economist to see the problems. Chemical pesticides cost $60 per acre, and pheromone products (one type of alternative to pesticides) cost $300 per acre. Labor accounts for much of the difference. When faced with that kind of economic decision, pollinators are not the top priority.

"Our ability to manage the world is limited by the complexity of nature," Forsyth said. Indeed, there’s no easy way to conserve something as complex as an ecosystem. Fred Stabler of the Bureau of Land Management pointed out the conflicts one encounters when trying to save an ecosystem—his organization used herbicides to get rid of exotic plants, which push native plants out of their habitats. But herbicides can kill pollinators and thus threaten native plants with the inability to reproduce.

Despite the obstacles, however, pollinator conservation does have its success stories. Although Steve Walker of Bat Conservation International recalls seeing bats with BB gunshots through their wings, and bats’ roosts are sometimes burned or destroyed with dynamite, more people are now trying to help bats. For example, the Bureau of Land Management is now making the effort to close off abandoned mines with bars so that bats can still roost in them, but people and other wildlife will not accidentally fall in or purposely harm the bats.

Things are looking up for the Brazil nut as well. The Peruvian government, anxious to preserve the economically vital Brazil nut crop, is now working with scientists to learn how to preserve the ecosystem, and the Bolivian government is interested in following suit. Interest in lowering pesticide use is also gaining support around the world. Sweden has lowered pesticide use by 50 percent without a loss in yield, according to Pimentel. In the U.S., insecticide use on Texas cotton fields has been reduced by nearly 90 percent since 1966. The National Fish and Wildlife Foundation is now making grants available to organizations that wish to restore pollinator habitats.

The future of pollinators and the lives of people depend on these efforts.

 The Malaysian servants peered into the bucket now holding the prince’s maimed body. They knew that their master had made a grave mistake by selfishly slicing into the honeycomb. But the bees showered down a golden mist to forgive and revive the prince, granting him a second chance.

ZooGoer 28(1) 1999.
Copyright 1999 Friends of the National Zoo.
All rights reserved.

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