Fight of the Bumblebee

There are more than 20,000 species of bees in the world, and about 800 in Canada. Almost all are wild native pollinators that have co-evolved with the plants that dominate our landscape, each with its own unique function. Giants by bee standards, bumblebees, with their furry coats, are particularly suited to a colder climate: they can fly in rain and snow, and can be found as far north as the Arctic Circle. The smallest bees are the size of a pinhead; a nest of 600 is no bigger than a walnut. Many bees are solitary, some of them cuckolders who steal into other nests to lay their eggs. But the best known of all bees is the one we have domesticated for thousands of years: the honeybee, or Apis mellifera, a species found on every continent except Antarctica. Among the most intelligent and manageable of insects, they have flourished in their adopted lands. Their colonies are an Adam Smith vision come to life, tens of thousands living in complex social hierarchies where labour is divided and each bee knows its role: the queen to lead, the nurses to clean the cells and feed the young, the drones and workers to forage in the fields, the guards to defend the nest.

Much has been written about the disappearance of honeybees since 2006, when David Hackenberg, a migratory beekeeper based in Pennsylvania, opened his 3,000 hives in central Florida to find that 80 percent of his colonies were gone. The syndrome was dubbed colony collapse disorder, and it has since killed about a third of American honeybee colonies each year. Canadian honeybees are also under siege, although not from CCD, which has yet to be identified in Canada. The causes are also mysterious. Even more mysterious are the threats faced by our wild bees, some of which have been declining steadily for decades. In eastern Canada, about half of our native bumblebee species are in trouble, yet it was pure luck that Colla happened across some research conducted by a doctoral student in the 1970s, which drew her attention to the rusty-patched bumblebee. Otherwise, she might not have noticed its decline, nor decided to examine historical collections at museums in Canada and the United States to chart the fortunes of other eastern species. (Her field guide to North American bumblebees, published by Princeton University Press, is forthcoming.)

When she defended her thesis on the rusty-patched bumblebee, a discussion about extinction ensued. “How many bumblebee species can we afford to lose and still be okay? ” asked one of her examiners. “None,” replied Colla, with all of the assuredness of a thirty-year-old whiz. “There’s not a lot of redundancy.” To which he responded, “Good luck with that.”

Packer, who lectures on biodiversity and entomology when he is not collecting specimens in Kenya or South America, thinks we might have predicted the collapse of the honeybee hives if we had paid more attention to the declines in wild bees that have worried conservation biologists for years. Such inattention could prove costly. The number of global crops that depend on animal pollination grows every year. Their value is estimated at $209 billion, and if you include livestock feed crops such as alfalfa and clover it is much higher. But while the number of foods that depend on pollinators has quadrupled since 1961, domesticated honeybee hives have not kept pace. This leads researchers to believe that wild bees are doing much of the work for free and not always getting the credit; a recent study in the United Kingdom suggests that only 34 percent of the country’s pollination services could be performed by honeybees under the most favourable conditions. So even the experts who have devoted their lives to studying honeybees will tell you they are just as concerned about the fate of wild pollinators like Sheila Colla’s rusty-patched bumblebee. The widespread decline of wild bees could have serious implications for both biodiversity and food production.

Little is known about pollination, given its essential contribution to our survival. “Great truths,” as the evolutionary biologist E. O. Wilson writes, “are sometimes so enveloping and exist in such plain view as to be invisible.” One such truth, he observes, “is the dominance on the land of flowering plants and insects.” This symbiotic evolutionary strategy developed around 130 million years ago, guaranteeing the hegemony of flowering plants, and the insects that fertilize them by delivering pollen from the male blossoms’ anthers to the females’ stigma. Some plants don’t require pollination; others rely on the wind to move pollen about. Among those that depend on animal pollinators, the lion’s share of the work is typically done by bees. But not all pollinators are created equal. Many flowers are shaped in such a way that only a certain bee’s tongue can reach their nectar; some bees store pollen balls in baskets behind their legs; others collect the yellow dust on their hairy coats, where it sticks for the same reason that a rubbed balloon clings to a seven-year-old’s head: static electricity.

Charles Darwin was obsessed with the bees that visited his garden in Kent, UK, and used the “humble-bee,” as he and others then referred to it, to explore the idea of co-evolution, though he did not call it that. “Thus I can understand how a flower and a bee might slowly become, either simultaneously or one after the other, modified and adapted in the most perfect manner to each other, by the continued preservation of individuals presenting mutual and slightly favourable deviations of structure,” he wrote in On the Origin of Species. He had observed that heartsease and red clover are visited exclusively by the bumblebee, and could imagine that both “would become very rare, or wholly disappear” if the bumblebee genus went extinct. When one species disappears, others follow, especially when that species may, like the rusty-patched bumblebee, act as a keystone. Researchers are looking into the possibility that the decline of the shrike, a songbird that impales bumblebees on hawthorns for its meals, may be intertwined with the bumblebee decline.

Just as bees and flowering plants co-evolved, so did bees and human beings. An ancient cave painting dated to 10,000 BC depicts a man robbing a hive, suggesting that we had already developed a taste for honey. By 3,000 BC, we were keeping artificial hives, which is probably when the relationship became beneficial for both parties. Bees pollinated our crops and provided us with honey, once the primary sweetener in many diets. In return, we built them safe houses in which to raise their broods; we cleared the land of forests, giving them sunnier meadows and more wild flowers for forage; and we introduced them to habitats around the world, where they, and the crops they pollinated, flourished. Without bees, the human race might never have developed agrarian societies, nor exploded in population.

The honeybee arrived in North America in 1622. While some colonies in Canada went feral, most today are managed by beekeepers, who must tend their hives carefully if the bees are to survive the deep cold of winter and a growing number of threats, from infestations of parasitic mites to deadly viruses and fungi. Still, from a farmer’s perspective, honeybees have much to recommend them. As well as providing a sweet side business (honey), they are easy to manage. Their hives can be immense, housing as many as 25,000 to 30,000 bees, which enables them to send more foragers into the field. And they are excellent communicators, waggle-dancing to share the discovery of a new food source with their hive mates, which allows them to exploit it more quickly.

The intensive practice of trucking bee colonies from one place to another is only about ten years old in Canada, but the value of the country’s pollination services is already estimated at $1.3 to $1.7 billion, at least ten times that of honey production, and a boon to struggling beekeepers who must now compete against cheaper imports from China, Australia, and South America. (Canadian beekeepers sell their honey for less than $2 a pound wholesale, which is sometimes just slightly more than what it costs to produce it.) As pollination becomes ever more lucrative, the distances travelled by migratory beekeepers have grown steadily. Last year, for instance, some 25,000 colonies were transported from Ontario to New Brunswick to pollinate blueberry crops. In part, this is because of built-in protectionism: while honey is sold on the global food market, where foreign producers can dictate prices, the market for pollination is strictly domestic. You can’t import pollinators, because beehives are not allowed to cross international borders. In theory, this protects our hives from disease.

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