The Decline of the Honeybee and Other Pollinators

Karen Edmundson Bean is a nationally published freelance journalist specializing in science and the environment. She is also an award-winning producer/writer/cinematographer of natural history and backcountry videos (http://Walking-Wild.com) and one of the few women to hold director of photography status in the International Cinematographers Guild. Her farm in Maple Falls is home to her cashmere goats, Shetland sheep and, of course, honeybees.

The articles in this series will take a closer look at the causes of pollinator decline, as well as what we all can do to help stop and hopefully reverse the dwindling number of native pollinating insects and honeybees.

Part 1

If the bee became extinct, man would only survive a few years beyond it. — Albert Einstein

He nearly got it right.

You sit down to dinner and one-third of your food suddenly disappears. You look up from your plate and realize that nearly every flowering plant has vanished. The song of birds has ceased, only a few birds remain. Small mammals and larger, gentle herbivores have disappeared. Some of the larger predators that still roam wild are headed your way, and they are very, very hungry. A bad dream following a large pizza too late at night? No, it’s simply the world without honeybees and other pollinators. A world that may be rapidly approaching.

From epicurean delights to fast-food feasts, we are dependent on pollinators for approximately one-third of the food we eat: fruits, vegetables and even meat. Our livestock feed, in part, on pollinated forage. It is estimated that honeybees alone pollinate one quarter of all crops in the United States. Without honeybees and other pollinators, 90 percent of all flowering plants would perish. Their destruction would result in the very quick death of many animal species that depend on plants for food, shelter and protective cover. The demise of those animals would greatly impact others, including humans.

Honeybees and other pollinators are such an integral part of our world, it’s difficult to imagine that they could disappear. Bees are survivors who have been around for a long time. Their ancestors were flying 80 million years ago. Bees predate modern man and have adapted to the dramatic climate changes that ended the lives of many other species. When our ancestors did appear, they figured out the value of honeybees quickly. Cave paintings from 6000 B.C. (or B.C.E.) depict honey harvests. Egyptians moved hives by water in their quest for more honey.

Today, there are between six and 11 species of honeybees in the world — experts don’t always agree on the number. These bees are a remarkably diverse group that range in size from the giant honeybees (Apis dorsata) of Asia, to the dwarf honeybees (Apis florea) who are established in a similar area that stretches from Pakistan to Southeast Asia. The Western, or European, honeybees (Apis mellifera) are the bees most Americans know as “honeybees.” They are a remarkably adaptable species that have traveled the world on their own and with human colonizers. Subspecies of Apis mellifera are found in every continent except Antarctica. All of the Apis produce honey and they all pollinate, but they are not the only pollinators.

Until the arrival of European settlers, there were no honeybees in the Americas. Every honeybee in the western hemisphere, wild or managed, is the descendant of an imported bee. They were introduced by American colonists in 1622. In the 1850s the difficulty of moving bees across the Rocky Mountains was overcome by placing the bees on boats to ship them to the West Coast.

In the last 400 years different subspecies of western honeybees have been imported to the western hemisphere in our on-going quest for better crop pollination and greater honey production. The subspecies, also called “races,” have common names, which reflect the area from which they originated.

The first to arrive with colonists were the somewhat aggressive German black bees. They were joined by the more docile Italians, the most prevalent race in the United States today. The gentle Carniolans hail from the Austrian Alps; the Caucasians from the Caucasus Mountains near the Black Sea; the aggressive Africans from East Africa; and the Russians from eastern Asia near the Sea of Japan. The most recent arrivals are the Australians who were first imported in 2005. There are pure strains of these bees, human-bred hybrids and feral hybrids that are the descendants of bees that decided to leave the confines of man-made hives and live wild.

There are nearly 4,000 species of native, pollinating bees in North America. Of these over 1,000 live in the Pacific Northwest. (The nonnative honeybees are not included in this number.) Some, like the bumblebees, are generalists: they visit a wide variety of flowers just like honeybees. Others are specialists: their distinctive tongues, size, shape and behavior restrict them to the pollination of specific plants. Some are so specialized they visit only one species of flower. None of our natives produce honey.

Surprisingly, the imported honeybees and the native pollinating bees live in harmony. “I’ve seen natives and nonnatives happily pollinating together,” says Dr. Nan Vance, research plant physiologist at the Pacific Northwest Research Station of the National Forest Service. “There seems to be enough room for all of them.”

Mace Vaughan of the Xerces Society for Invertebrate Conservation echoes this: “Honeybees aren’t in competition with natives. Our natives don’t need as much nectar; they don’t store food like honeybees. Bumblebee queens overwinter, but the solitary bees die. Their young spend the winter stacked away.” The natives tend to be specialists, while honeybees have more eclectic tastes, including imported plants. “The only potential conflict,” Vaughan points out “is between honeybees and bumblebees. They are both generalists.”

Native and imported bees also prefer very different nest sites. Honeybees like large cavities, from hollow trees to beehives. Bumblebees, one of the few social native bees, make nests in the ground, often in old rodent burrows. Solitary bees need only enough room to tuck away their young for the winter, usually lined up in a tube formation, one after the other. The difference in native and nonnative bee nest design has an added benefit for native bees: the honeybees keep their parasites and diseases to themselves.

Honeybees create honeycomb in which to raise their young and store year-round supplies of food, both honey and pollen. No native bee creates a similar structure, according to Vaughan. The spread of many pests and diseases that affect honeybees depends on the year-round movement of bees across the comb. Because of this, a disease or parasite may move from a honeybee to a native bee, but its further spread is stopped by the lack of an organized beehive. “It’s like we have the flu and colds that make us sick, but we don’t pass them on to our dogs and cats,” Vaughan explains.

The honeybees and native bees may live in far more harmony than cats and dogs, but the modern world has not been in harmony with them. The last 60 years have been rough on all pollinators. In the 1940s there were over five million managed colonies of honeybees in the United States. Today there are just over two million, and their numbers are declining, both in North America and worldwide.

The feral honeybees and the native pollinators have had an equally hard time. Wild honeybees were nearly wiped out in the last few years, although their numbers are once again rising. Native pollinators have been equally hard hit. The populations of native bee species and some butterflies in the United Sates are in a continuing decline, according to a study by the National Academy of Sciences released this year. Two species of bats and 13 species of bird pollinators are now considered endangered by the U.S. Fish and Wildlife Service. That is just in the United States. The entire world now faces a decline of native pollinators.

Over 100 species of birds and more than 80 mammals that pollinate are considered threatened or extinct by the International Union for the Conservation of Nature and Natural Resources (IUCN), a network that includes scientists, experts, government agencies and non-governmental organizations from around the world. Each country has its own tale to tell. In southern India, nearly all of the native bees died in the 1990s when they became infected with an imported virus. In Iraq, smoke from the burning oil wells during the Gulf War decimated most of the country’s bee colonies.

Recent studies in the United Kingdom and the Netherlands have shown that bee diversity is down 80 percent in the sites researched, and that “bee species are declining or have become extinct in Britain.” The studies also revealed that the numbers of wildflowers that depend on pollination have dropped by 70 percent. Which came first, the decline in wildflowers or the decline in pollinators, has yet to be determined. The cause, however, was clear. The study, lead by Jacobus Biesmeijer, an ecologist from the University of Leeds in Great Britain, cited habitat loss, pesticide use and abnormal amounts of nutrients in streams and lakes, often from sewage and fertilizers.

In the United States natives have been hit by two of those factors: the loss of habitat and the use of pesticides. “Certain landscapes have just been nailed,” Vaughan comments. “Nature has been overrun and bee diversity has fallen. But the cause depends on the ecosystem and the region. In California’s central valley the lack of habitat is driving the lack of native bees. In New Jersey, it’s pesticides.”

For honeybees “the bad days of pesticides are behind us,” says Dr. Steve Sheppard, who holds the Thurber Chair of Apiculture, Department of Entomology, Washington State University, Pullman. But that past is relatively recent. Studies in 1992 and 1996 showed that bee die-offs due to pesticides cost beekeepers over $14 million dollars every year — a financial loss great enough to cause many beekeepers to leave the business. Lawsuits, which cite pesticides as the cause of the deaths of managed bee colonies, continue to be filed today. As pesticides dropped down in the rank of honeybee killers in the 1990s, a more deadly foe appeared — the varroa mite.

“If you ask 100 commercial beekeepers what’s causing the decline, they’ll tell you it’s varroa mites,” Sheppard explains. “Before varroa, a 10 to 15 percent winter loss was normal for good beekeepers in cold areas … . Over the last decade it’s become a 30, 40, 50 percent loss.” The mites hit the feral honeybees as well. Varroa mites ride on honeybees. When bees from infected colonies interact with feral bees, the mites spread. This spread is believed to be responsible for the near demise of the feral honeybee colonies.

Varroa mites are just one of the imported pests and diseases that have impacted pollinators. An imported virus caused the near demise of one native bumblebee, Bombus occidentalis, which was once one of the most common bumblebees in the West.

Imported diseases and pests have increasingly accounted for pollinator losses, but the decline in honeybees began in the 1950s. “The first decline, from five million [colonies] to three million, was because people moved to the cities,” says Sheppard. The demise of small family farms was only one of the challenges to all pollinators presented by our modern age.

After World War II, pollinators took a variety of blows as our culture and technology rapidly changed. The majority of small farms, which traditionally raised a diversity of crops, were replaced by larger farms and agricultural corporations, which often plant thousands of acres with only one crop. Pesticide use increased dramatically. Although there is now greater understanding and restraint surrounding the use of pesticides, they continue to be an integral part of non-organic agriculture.

Forests gave way to forestry plantations where herbicides and insecticides are also used. Urban centers grew, replacing small farms and open spaces with concrete and asphalt. The ease of rapid transit between countries and states has spread parasites and diseases worldwide. Each of these modern developments has contributed to the on-going decline in pollinators. If that decline continues, the impact will be felt by all life on earth.

The majority of the blame for the decline of pollinators can be laid at the feet of humans. We caused the problem, but we may just be able to solve it. §

Next Month: Habitat Loss and Pesticides