Sweeter Than Honey: Honeybees pollinate dozens of important crops

If the calendar says September, fall must be on its way. Temperatures will drop, leaves will turn and farmers' markets will overflow with pumpkins and apples. Those fruits of fall that give harvest festivals their color and crunch are the result of hard work months earlier by that industrious insect, the honeybee. Spring may be the season of the birds and the bees, but fall is a good time to reflect on all we owe to Apis mellifera, the European or Western honeybee.

Honey is, of course, the honeybee's most obvious product. Whether you squeeze it from plastic straws, pour it in your tea or drizzle it on pancakes, honey satisfies the sweet tooth. According to figures from the USDA's National Agricultural Statistics Service, Missouri's 15,000 honeybee colonies produced $1,028,000 worth of honey in 2006 - and that doesn't even count the colonies owned by hobbyists with fewer than five hives.

The honeybee's role in pollination is even larger, if not sweeter. Nationwide, about $15 billion worth of fruits, nuts and vegetables - around 100 crops – rely on pollination by
honeybees every year. In recognition of its contribution to agriculture, the honeybee is honored as the Missouri state insect.

The hive life

One honeybee colony can contain about 50,000 bees at full summertime strength. One queen bee does nothing but lay eggs - up to 2,000 per day - and male drones exist solely for mating. Most of the bees are female workers. As the workers age, they change jobs.

"The youngest ones do the cleaning," said beekeeper and farmer Ellen Knoernschild of Centennial Farm and Orchard in Augusta. "When they get a few days older they start feeding the larvae, and then, when they get older yet, they start working on making wax and working on the honey. And when they are close to being geriatric, they get sent out to the flowers."

This self-contained community of thousands of efficient - and relatively docile - workers can be moved from field to field, pollinating swaths of crop monocultures at each stop. Knoernschild considers her 24 hives essential for pollinating apples, blackberries, black raspberries, pumpkins and melons, and helpful for producing larger peaches and strawberries.

A foraging worker bee stuffed with nectar brings the load back to the hive, passes it off to a younger worker and returns to the field to collect more. Inside the hive, the younger bee converts the nectar to honey by mixing it with enzymes that transform the sugars, depositing it in a honeycomb and fanning it to evaporate away some of the water.

"You can see when the honey flow is really on; there are bunches of bees standing at the entrance, flapping their wings and bringing air up through the hive," Knoernschild said. "Bees work hard."

Honeybees depend on their honey supply to get them through the winter when nectar isn't available and temperatures are too cold for flying. Bees do not hibernate for the winter,
but they do hunker down in the hive and huddle up to keep warm.

"From first frost until roughly mid-February, depending on the weather, they basically are trying to keep warm and stay alive," said Steve Harris, president of the Eastern Missouri
Beekeepers Association. He keeps six to 12 hives in the O'Fallon area. "They get in what is called a cluster or ball. ... They are constantly moving. The gals on the inside of the cluster are moving to the outside, and the gals on the outside are moving to the inside, and the queen is in the middle. In the inside of the cluster, it is roughly 95 degrees. If it's 0 degrees outside, it's probably a little lower, but generally it is at 95 degrees."

To fuel this living heater, the bees need plenty of food. Beekeepers leave some honey in the hives, and most also provide sugar water, but even so, colder than normal temperatures can throw off calculations or make it too cold for the bees to get to the food. Both Knoernschild and Harris lost hives this past winter to cold and starvation.

Disappearing bees

In the 1980s, honeybees were hit hard by infestations of two parasites, tracheal and varroa mites. Beekeepers now use pesticides regularly to help control the mites, but feral honeybee colonies all but disappeared for a while.

This past winter, a mysterious honeybee killer, dubbed Colony Collapse Disorder, again decimated colonies. Affected beekeepers across the country lost from 30 to 90 percent of their colonies, far more than typical winter kill. What's more,
beekeepers are finding their hives not just dead, but abandoned. Young bees remain in the hives and the honeycombs are full, but the adult bees disappear with few or no dead bodies found nearby. Even more strange, neighboring bee colonies do not rob the remaining honey.

"Bees will get honey wherever they can, and if there is a weaker hive, it will be robbed out by a stronger hive," Knoernschild said. "Hives that have Colony Collapse Disorder - the other bees will not rob out that honey. There is something about it."

Determining the extent of CCD is difficult at best. In the absence of any rigorous program to monitor honeybee health, agriculture officials and beekeepers rely largely on word of mouth. "I've talked to a lot of beekeepers about it and a lot of them say they have it," said Ken Norman, president of the Missouri State Beekeepers Association. "They believe there is
something new out there they haven't seen before, and they've been in business a long time."

Theories abound as to what is causing CCD. In June, a CCD working group from the USDA identified four prime suspects: varroa mites, an unknown disease, pesticide poisoning and stress, possibly induced by poor nutrition, drought or long-distance travel. So-called migratory beekeepers truck their bees around the country, following pollination cycles. The California almond crop alone requires 1.3 million colonies. Just as in people, the stress of travel could compromise bees' immune systems, making them more susceptible to disease. "It is true here in Missouri that most of the migratory beekeepers lost the higher percentage," Norman said.

But the question of what causes CCD is still very much open. "I would say what the working group did was identify four likely hypotheses, but there's no indisputable data in support of or to refute any of them," said May Berenbaum, head of the entomology department at the University of Illinois, Urbana-Champaign and chair of a recent National Academy of Sciences committee on the status of pollinators in North America.

Beyond honeybees

Honeybees are the workhouses of modern agriculture, but they are relative newcomers to the North American pollination scene. Before European settlers brought honeybees here in the 1600s, native plants relied on native bees, wasps, flies, butterflies, birds, bats and other small mammals for pollination. These animals are still essential partners in this ecological relationship, and they might make a sizable, if underappreciated, contribution to today's agriculture. One estimate puts the value of crop pollination by native bees at $3 billion per year.

Some farmers have tapped into this potential. Bumblebees pollinate greenhouse tomatoes, leafcutter bees pollinate alfalfa grown for seed in the Pacific Northwest and mason bees are put to work in apple and cherry orchards. These practices have not caught on locally, mainly because alternative pollinators are perceived to be less efficient.

Another issue is the status of wild pollinators. Some bumblebees are known to be declining, but little is known about how most species are faring.

In the meantime, Norman encourages homeowners and others to take one small step to help maintain pollinator populations. He asks people to use pesticides carefully, if at all. "Use it wisely, use at it at dusk, use it when the bees aren't flying, use it according to directions, so we don't have a bee kill," he said. "Do not randomly use pesticides that kill bees and other pollinators because we need all we can get in Missouri and in the U.S."