JUNE 19, 2018
BEES ARE IN TROUBLE. The alarm bells began ringing a little over a decade ago, when beekeepers entered previously healthy apiaries and found most of their colonies dead. Today, in the United States, 35-45 percent of colonies die every year, about a million colonies annually, a tragedy in itself but also a serious economic challenge for the crops that depend on honeybees for pollination.
There is a lesser-known bee story, though: the decline of wild bees. Ultimately, it may be the more alarming story. There are over 20,000 bee species in the world, and 43 percent of them are diminishing or endangered. Most wild bees are small and solitary, nesting in holes in the ground or wood. Some, such as bumblebees, inhabit more complex social colonies of a few hundred or thousand individuals. Until recently, they were studied by only a tiny cadre of dedicated researchers, with little public awareness of the scientists or the bees they studied. Although wild bees are ecologically critical, funding to study them has been dwarfed by honeybee research dollars for the obvious reason: honeybees' perceived agricultural value.
That situation is changing though, and if there's a silver lining to the bee crisis it's in the growing attention being paid to wild bees. Broader awareness of the pollination services they provide for crops and natural ecosystems has opened the spout of research dollars.
The factors affecting wild bee populations are the same as those responsible for the death of honeybee colonies. It's not one thing, but rather a trio of factors intersecting in a perfect storm of insults.
Pesticides are clearly the most obvious. Many of them kill insects indiscriminately. Their direct toxic effects have long been known, but recent studies reveal synergistic impacts from low doses of many chemicals. It's a little-understood phenomenon for any organism, but bees have now become the model for examining the interactive effects that accrue from tiny amounts of pesticides. We've also come to understand that pesticides previously thought to be harmless for bees, such as fungicides, can be toxic, particularly when bees are also exposed to other chemicals. And finally, weed killers were once thought to be benign for bees, but, in cleaning fields of weeds, they create nutritional deserts that leave bees scrambling for the diverse nectar and pollen they require as food.
Nutritional deprivation is the second challenge. Agriculture is the main culprit, as farms become increasingly large, with only a single crop planted over entire regions. Almond orchards in Southern California, for example, sprawl over an almost unbroken stretch of 800,000 acres, with the ground beneath the trees kept clean of other plants that could serve as a source of food for bees. There are few wild bees left alive in this and other agricultural bee wastelands, so honeybees must be trucked in to pollinate when crops bloom.
Diseases and parasites are the third pillar in this real-life bee disaster movie. Many parasites and diseases have been introduced and spread throughout the world, including the devastating Varroa mite for honeybees, but they alone are not responsible for declining bee problems. Both pesticide exposure and poor nutrition compromise bee immune systems and, ironically, also reduce bees' ability to detoxify pesticides. It's this interaction between pesticides, poor nutrition, and diseases and parasites that is in fact bringing bees down.
Thor Hanson's love letter to wild bees, Buzz: The Nature and Necessity of Bees, is thus timely. He is that rare breed of scientist who has crossed over into writing about science and nature for a public audience. He is even more unusual in that his writing is accessible. About bees he's an amateur, but a serious one, who has taken rigorous courses in bee systematics and developed his own favorite stories about the wild bee world.
To be sure, his book is not a comprehensive guide, but rather a collection of connected essays that reveal fascinating aspects of wild bee biology. He writes with particular affection for one group of bees, Nomia, the alkali bees, known for their habit of aggregating their nests in salt pans and dry lake beds. His nickname for these bees, "flying pearls," refers to their opalescent external skeleton. In one memorable scene, he describes being in the midst of millions of these flying pearls in Washington's Touchet Valley, an irrigated oasis of alfalfa fields where farmers maintain salty soils nearby to host the crop's alkali bee pollinators. He writes:
Driving out of the Touchet Valley, Noah [his son] and I stopped one last time to listen to the bees. With the car turned off and the windows down, they sounded like a great vibration, a low bowed note droning ceaselessly. For [...] local farmers, that music was the sound of their livelihood and a backdrop to their lives.
Hanson also delves eloquently into the evolution of highly social behavior in bees with aggregated nests. A major topic of scientific study across a wide range of organisms, sociality research in insects took off in the 1970s, spurred by the work of ant biologist E. O. Wilson and bee specialist Charles Michener, whom Hanson describes as the "patriarch of bee studies."
I had a front-row seat to this productive era as a research assistant at the University of Kansas working for "Mich," as we fondly called him. I was assigned what seemed to be the dullest of topics, studying the mouthparts of bees with long tongues, but the results were anything but dry. We discovered that two groups of highly social bees, the honeybees and the stingless bees, had mouthparts with different structures, spurring further work into their anatomy and behaviors that suggested these groups had evolved their eusocial behavior independently. Highly social behavior is fairly rare in the animal world, so elucidating another example of its evolution was considered a major finding at the time.
Hanson describes the evolution of social behavior among bees as a "relentless process of reinvention that often arrives at the same solutions again and again." Bees have been particularly important in studies of sociality because social behavior arose more times in them than in any other taxonomic group, suggesting common pathways that began with the aggregations of thousands or even millions of solitary nests in prime soil habitats. Advanced social behavior gradually progressed toward defending each other's nests and then on to more highly cooperative behaviors involving brood provisioning and rearing, eventually reaching the eusocial form of sociality featuring worker and queen castes, with workers rarely or never reproducing and the queen doing most or all of the egg laying.
Darwin considered social insects to be a major challenge to his theory of evolution, since the idea of workers altruistically sacrificing their own reproduction to that of their queen didn't seem to fit with his ideas about natural selection. However, research with bees and other social insects such as ants and termites indicates that the survival advantage of social behavior can more than account for workers sacrificing their own reproduction for their queen, to whom they are genetically related; in this way, at least some of their genes are passed on to future generations.
Hanson makes accessible plenty of other dense and even jargon-filled topics like anatomy, for instance. He describes the odor receptors of bees simply as "microscopic pits and pores," rather than using entomologist jargon like chaetica, trichoid, and basiconic capitate peg sensilla. He likens bees' olfactory capabilities to "wine connoisseurs appreciating a complex bouquet [...] teasing apart the subtleties of a pheromone or picking out the fragrances of leaf, tree, soil and water."
One of his particularly interesting stories exposes the intricate relationships between plants and pollinators. He describes exotic male orchid bees tricked into pollinating flowers by scents identical to the pheromones that attract male bees to mate with females. Other plants provide caffeine in their nectar, which induces bees to remember and return to their flowers.
I also appreciated Hanson's choices of what not to write about. He barely mentions honeybees. It's irritating for wild bee enthusiasts to stand in the shadow of the honeybee's fame, but while occasionally alluding to such frustration, Hanson wisely doesn't dwell on the internal politics of the bee research community.
Suffice it to say that wild bee enthusiasts disdainfully refer to honeybees as "pollen pigs," an allusion to the broad spectrum of flowers they visit. By contrast, many wild bee species specialize in one or a small number of floral sources. As mentioned earlier, honeybee researchers and beekeepers have mostly ignored wild bees as irrelevant to the important task of crop pollination, which is heavily dependent on managed honeybee colonies being moved into fields during bloom. Because the current bee crisis afflicts both managed and wild bees, one felicitous side effect has been improved relations, even collaboration, between members of the two camps.
I have only a minor quibble with Hanson's otherwise appealing book. He's clearly fond of wild bee researchers as much as the bees they study, but his writing about those he interviewed is too narrowly focused on their obsessive qualities, depicting them as frazzled, overworked, and eccentric. There may be some truth to these stereotypes, but there's also considerable personal depth and variation among scientists.
Hanson is not alone in painting a too-narrow picture of those who practice science. I recently served as a jury member for a competition involving science books written for the general public. Almost all the books used the same tired stereotypes around scientific personalities. Some of us are, indeed, absentminded, while others go through life with quiet efficiency. Some are frazzled and overworked, but many of us go home at night to families and friends without giving work a second thought until the next day. And we all have interests outside of science. Writers would be well served to depict our nuances and subtleties with as much care as they do the topics we study.
Finally, it should be said that Hanson dips into the plight of bees only toward the end of Buzz, describing the anguish of researchers seeing some of their favorite species go extinct. He notes that the feared bee-free dystopian future grimly predicted by apiculturists has already arrived in some regions, with so few bees remaining in some Chinese apple orchards that trees have to be pollinated by thousands of seasonal workers swabbing flowers with long sticks topped by chicken feathers or cigarette filters.
Still, it's not the plight of bees that sticks with me from Buzz, but rather a section late in the book in which we find Hanson and his young son Noah crouched down in front of the shed where he writes. They are waiting patiently for a bumblebee queen to emerge from her newly founded nest for no reason beyond their own enchantment.
That's the core message of this charming book: be fascinated, and hopefully that will lead us to take action to protect these marvelous and critically important insects.
Mark L. Winston is a professor of Apiculture and Social Insects at Simon Fraser University as well as the founding director of the university's Morris J. Wosk Centre for Dialogue. He is also the author of Bee Time: Lessons from the Hive and the recently published book Listening to the Bees with co-author poet Renée Sarojini Saklikar.