Share / Discuss

Rebecca Zhou in a bee suit shot through an observation hive

Hive Minded

Unlocking—and learning from—the secret life of bees

Orange abdomen, pink thorax.

Carefully, as a honeybee darts its tiny tongue to slurp concentrated sugar water, Rebecca Zhou ’19 readies her rainbow of paint pens. She shakes the orange and pink ones to get the color flowing, then gently dabs the bee’s fuzzy body—two dots on the abdomen, one on the thorax. The tiny forager, drugged-up on a sweet solution three times as potent as nectar in nature, hardly seems to notice. Later, Zhou will try to spot the marked bee as it jets back to its hive, fresh from its food run.

“I’m actually terrified of bees!” Zhou admits. You wouldn’t know it. On this steamy July morning outside Martin Biological Laboratory, clad in sunhat, T-shirt, and shorts, she’s more protected from the heat than from a potential sting.

A honeybee study may seem a strange choice for a student with melissophobia, but Zhou’s anxiety actually factored into her decision to participate: She wanted to face her fear.

A Velay fellow, Zhou spent her summer recording sights, sounds, and scents in one of several Swarthmore projects exploring the secrets of this remarkable insect. In doing so, she and her fellow student researchers joined a colony of Swarthmoreans acting on behalf of—and in the vein of—the beloved bee.

All abuzz

Susanne Weil ’80’s husband, Peter Glover, first put the bug in her ear.

“We’re going to keep bees!” he declared in 2008, fresh from a Master Gardeners symposium led by the state apiarist. An English professor at Centralia College in Washington state, Weil knew zero about honeybees, but the timing proved fortuitous: A week later, the couple watched PBS’s Silence of the Bees documentary, depicting the acceleration of Apis mellifera die-offs.

“It alarmed and upset me,” Weil says, “and what seemed like a fun adventure suddenly looked like important environmental work.”

The documentary described colony collapse disorder (CCD), a mysterious condition that thrust the western honeybee into the international spotlight. Winter honeybee losses—which typically hover between 15 and 25 percent nationally—jumped to 35.8 percent in 2007–08, with 60 percent of those losses likely tied to CCD, according to the U.S. Department of Agriculture.

“With CCD, you have bees going out, but they’re not able to make it back,” says Chris Mayack, a visiting assistant professor of evolution who mentored Zhou’s summer honeybee project. “You have no dead bees in or around the hive, you still have viable brood, there are food stores—everything else seems normal except the bees aren’t there.”

The root cause of CCD is still unknown, though most scientists agree it’s likely a combination of pesticides, parasites, and a lack of foraging resources. Although the number of CCD cases has dropped significantly over the past decade, bees are still suffering, with the Varroa mite—a destructive parasite that infests hives—ultimately being the No. 1 plague on U.S. honeybee health.

“Beekeepers on average are losing about 30 percent of their hives each year,” Mayack says, “so the focus has shifted to looking at colony collapse in general.”

Colony losses have been a frustration for Weil, who went from “newbee” to a certified instructor with seven hives of her own: In 2016, apiarists in her area of southwest Washington lost an average of 45 percent of their bees.

“We know some who lost all,” she says.

The couple’s growth as beekeepers has taken years of practice and patience, but they began like expectant parents, “rehearsing ahead of time every step in hiving our two new bee colonies—we were afraid of harming them through some rookie mistake,” she says.

They quickly discovered that, like children, “bees don’t read the books, and we had to reconnoiter when they buzzed outside the proverbial rules.” They learned to hive swarms, harvest honey, treat for diseases, and make difficult life-and-death decisions. Ultimately, they learned to listen.

“Observing bees at work fascinates me,” Weil says. “I love the calming, meditative feeling I get watching their dancelike flight as they hover at the hive entrance, the arc of the foragers taking off in search of food. It’s fun to watch what colors of pollen they bring back in their baskets and speculate what plants produced those colors.

“But most important,” Weil adds, “I get a feeling for the disposition, the temperament, of each colony—and the bees get used to me.”

A 2010 study shows that even in their six- to seven-week life span, worker bees can learn to recognize individuals, and Weil finds that developing a relationship with her “girls”—worker bees are all female—helps her be a better beekeeper ... and living creature.

“If you devote the time and care,” she says, coffee in hand as she enjoys the day’s apiary garden ballet, “bees will reward you in so many ways.”

Plight of the bumblebee

Despite their highly publicized struggles, honeybees are not going extinct, notes Michael Roswell ’11, an ecology and evolution Ph.D. student at Rutgers. As of April 1, 2.89 million colonies—each with thousands of bees—were recorded by the USDA among operators of five or more hives.

But many of the country’s roughly 4,000 native bee species aren’t faring as well—because of habitat loss, pesticide use, climate change, and other factors—or receiving the widespread attention afforded to their honey-making cousins.

According to the Xerces Society for Invertebrate Conservation, 28 percent of North American bumblebees face some risk of extinction. Early this year, the rusty patched bumblebee—native to much of the upper Midwest and Northeast—became the first wild bee in the continental U.S. to be declared endangered by the U.S. Fish and Wildlife Service. Bombus pensylvanicus, a common bumblebee around Swarthmore 20 or 30 years ago, Roswell says, is listed as “vulnerable” by the International Union for Conservation of Nature.

“We know for some species that have collapsed really rapidly that something changed,” Roswell says. “But for most native bee species, we don’t have good enough baseline data to show how current distributions relate to that of the past.”

That’s beginning to change, as interest in native bees has grown, according to David Inouye ’71, a professor emeritus of biology at the University of Maryland.

“Historically, there haven’t been people consistently monitoring populations,” he says. “I think people assumed that bees were always going to be there.”

Inouye has researched native bees at Colorado’s Rocky Mountain Biological Laboratory since 1973, when a group set out to study pollinators’ relationship with wildflowers. One summer of research turned into two—which turned into 44 years of data on temperature, precipitation, and snowmelt changes and the effect they had on local wildflowers and pollinators.

“The growing season is getting longer,” Inouye says, “but although the date of the first flowers is shifting earlier, the date of the last hard frost hasn’t changed significantly.”

That means there’s a greater chance of frost damage not only to flowers but to fruit trees—and to the pollinators themselves.

“Bumblebee queens overwinter underground, and when the snow melts and the ground warms up, they come out,” Inouye says. “But the timing of their response is not matching the timing of the earliest flowers. There’s a risk that pollinators may not have all the resources they need to complete their reproductive cycle.”

Planting for pollinators

That synchronization between bees and flowers is of particular interest to Bethanne Bruninga-Socolar ’10, a Ph.D. student at Rutgers whose dissertation centers on foraging behavior and how bees respond to the availability of plant species.

“Bees depend on plant products for food in every part of their life cycle,” says Bruninga-Socolar, who works alongside Roswell in a pollinator lab led by Rutgers professor Rachael Winfree. “Eighty-seven percent of flowering plant species depend on pollination provided by animals—mostly bees.”

Initially interested in researching general insect ecology, Bruninga-Socolar changed her focus.

“I was hooked by bees’ diversity and the essential role they play in both human and natural ecosystems,” she says. “Plus, bees are super cute and surprisingly clumsy, which makes it really fun to observe them.”

Unlike the famously hierarchical honeybee, many native species—carpenter bees, leafcutter bees, mason bees, etc.—are solitary, building nests, finding food sources, and raising young without the help of a caste system or colony.

Roswell hopes that by studying bees’ behavior and environment, we can reverse their decline. His research, which centers on habitat enhancements and restorations that support pollinators—specifically New Jersey’s 400 native bee species—focuses on finding better ways to compare biodiversity and studying whether male and female bees prefer different kinds of flowers. (Roswell’s short answer: They do, though he’s eager to understand more.)

At Swarthmore’s Scott Arboretum, plants are chosen to appeal to pollinators’ preferences, says horticulturist Josh Coceano. “We also support bees by having early- and late-blooming plants, as it’s not uncommon to see bees foraging in February and November.”

Specifically, the Arboretum’s Pollinator Garden, designed by Mara Baird ’79 as a residential-scale example for homeowners, caters to the food and shelter needs of a range of insects, birds, and bats. The garden, between Martin Biological Laboratory and the Cornell Science Library, was named a Certified Wildlife Habitat by the National Wildlife Foundation, and its ethos inspires the College in many ways.

Even gardening novices can do their part by planting flowers that support pollination, says Inouye, who chairs the steering committee for the North American Pollinator Protection Campaign (NAPPC). Along with its parent organization, the nonprofit Pollinator Partnership, NAPPC created planting guides tailored to 31 ecoregions around the country.

“This can even be done in urban areas,” Inouye says. “It’s surprising, the diversity of native bees that can survive in cities if there are flowers.”

He recommends limiting the use of pesticides, especially neonicotinoids, which have been linked to bee paralysis and death, and recognizing Earth’s complex food web in which pollinators play a crucial role.

“At the NAPPC annual conference, next to each dish at our reception is a little sign: ‘These green beans were brought to you by pollinators,’ ‘This chocolate was brought to you by pollinators,’” Inouye says. “We’re trying to raise awareness among consumers that about one out of every three bites of food that you eat comes to you courtesy of pollination.”

Thinking inside the box

One creative company is tapping into that statistic. At the startup Bee Vectoring Technology (BVT), researchers are using the insects themselves to deliver a natural pest- and disease-control solution to berries, tomatoes, and other plants.

“Biological crop protection has come in favor the last 10 or so years,” says CEO Ashish Malik ’84. “As consumers, we don’t like the use of chemicals on our food. So how do we get farmers to use less chemicals on the crops that they grow?”

Through BVT’s setup, commercially reared bees passing through their hive pick up an organic biocontrol powder, which includes a naturally occurring fungus that prevents numerous plant diseases. The bees then distribute the powder to individual flowers, limiting the need for conventional crop-protection measures.

“Other products are sprayed using tractors and other machinery, which uses a lot of water and wastes a lot of product,” Malik says. “Through vectoring, we’re able to reduce the quantities of active ingredient by as much as 99 percent. It’s extremely efficient, effective, and highly sustainable.”

It also poses no health risks to bees, people, or the environment, Malik says. But the process isn’t a panacea.

“Plants see many pests in the environment: root diseases, leaf diseases, insects, weeds,” he notes. “We can’t address the pests that aren’t coming through the flower, but within an overall program, we can greatly reduce the amount of chemicals that are used.”

Founded in 2012, the company is still prerevenue and about halfway through its approval process with the Environmental Protection Agency. BVT’s research and development has focused largely on bumblebees and strawberry crops, but Malik is excited about his system’s wider potential.

“Out here in California, a million honeybee hives are brought in every Valentine’s Day to pollinate a million acres of almond trees,” he says. “These trees are affected by a disease our microbe could help manage. It’s a perfect opportunity for this disruptive technology.”

Worker bees

Perhaps the next advances in bee science will be born from Swarthmore’s Martin biology lab, where three separate projects synergistically overlap. Bee casualties from one study are sometimes used in another to test their chemical exposomes. Data from a project focused on pheromones is gathered simultaneously with one studying bees as a superorganism.

“What is the difference, really, between individual bees and individual cells?” says Brian Shields ’18, who assisted with a project led by Talia Borofsky ’18 exploring whether honeybees’ decision-making is similar to neurons firing in the brain. “It blurs the lines between what we consider a discrete living thing.”

Honeybees are in constant communication, “speaking” through a series of dances that convey the distance of nectar and pollen—a figure-eight waggle dance when food is far afield, a circular dance when the source is closer. When the food supply changes—such as when students swap in a feeder with a reduced-sugar solution—the bees project a stop signal telling dancers to end their movements.

“It’s like a really high-pitched ‘beep!’” says Rebecca Zhou ’19, who after a morning of marking honeybees outside has returned to the lab to begin her recordings. “Even without a microphone you can hear it.”

Zhou is interested in whether the bees also communicate through scent—if they’re in a dark or loud environment where they can’t see or hear, how do they get their stop message across? Using a delicate, odor-collecting solid phase microextraction fiber, Zhou can detect and collect pheromone molecules released from the bees.

Armed with a microphone, a field sampler, and—this time—a protective veil and suit, Zhou settles in among the flying bees.

“Following pink thorax, blue abdomen,” she records. “Waggle dancing. Possible stop signal. Stop signal. Multiple stop signals.”

Though her work with bees will probably end with this project, Zhou says she gained a great appreciation for the insects—and the wisdom they can impart.

“Bees are like people,” Zhou says. “They’re very altruistic. They are really community-focused. And they rely on each other to survive.”

Benefiting Bees