Catching the buzz: Researchers key on honeybees

Entomologist Gloria DeGrandi-Hoffman (right) and her student aid, Emily Watkins de Jong, inspect a honeybee colony at the Carl Hayden Bee Research Center in Tucson, Arizona. The researchers are studying the health and nutrition of honeybees, the most important pollinators of our crops. (Photograph by Dieu My Nguyen)
Entomologist Gloria DeGrandi-Hoffman (right) and her student aid, Emily Watkins de Jong, inspect a honeybee colony at the Carl Hayden Bee Research Center in Tucson, Arizona. The researchers are studying the health and nutrition of honeybees, the most important pollinators of our crops. (Photograph by Dieu My Nguyen)

On a sunny September morning in Tucson, Gloria DeGrandi-Hoffman holds up a rectangular wooden frame that houses a colony of honeybees. The air buzzes as tiny winged speckles flutter about.

“Oh, yeah. This is beautiful,” says DeGrandi-Hoffman, an entomologist and research leader at the U.S. Department of Agriculture’s Carl Hayden Bee Research Center. She raises her head to see the honeycomb on the frame better through the face net of her white bee suit.

Bees swarm on the frame like an orderly dance party. DeGrandi-Hoffman and her student aid, Emily Watkins de Jong, shake the bees off their dance floor to inspect the eggs laid in the comb. The two bee researchers are studying agricultural chemicals, varroa mites and the lack of natural forage— the three main factors affecting the health of bees, the most important pollinators of our crops.

How it all began

DeGrandi-Hoffman discovered her fascination with the micro-world of insects as a child. She loved to turn over logs and peek under rocks in the farmlands of Pennsylvania, where she was raised.

She attended Pennsylvania State University for her bachelor’s degree in biology (1975) and master’s degree in entomology (1980). She continued to study entomology at Michigan State University, where she earned a doctorate in 1983.

Her studies kept her connected to her childhood fascination. “Insects are the most incredible organisms on Earth to me,” she says. “I love talking about them and learning about them.”

Even now, as she approaches her 60s, she is still committed to honeybees. For DeGrandi-Hoffman, a honeybee colony is an invertebrate model of collaboration, a model we can learn from. “Honeybees are an organism that I could synthesize all the things I like together—the organization of a colony, individual bees working together to sustain a population and pollinate field crops,” she says. “I like being in the fields, among the orchards. I like watching bees on flowers, how they collect pollen and nectar. I like beekeeping.”

As a graduate student, DeGrandi-Hoffman first observed the changing nature of the environment. The number of flowers changed from season to season, and the weather fluctuated from cloudy to sunny.

The bees responded. They behaved differently, depending on the season and the availability of natural forage and pollen.

The young researcher wanted to capture that variation in the life of a bee population, so she built computer models that simulated pollination and predicted crop yields. This conceptual framework of a biological system, including its components and how they interact, illustrates the biological functions that underlie the life of a population.

In 1985, recognizing the novelty of her pollination models, the Carl Hayden Bee Research Center invited DeGrandi-Hoffman to bring her work to Tucson.

Today, DeGrandi-Hoffman directs the research at the bee center named after Carl Hayden, the late U.S. senator who secured funding for bee research in Arizona. The idea for the bee lab began in the 1940s, when farmers became concerned about the effects of insecticides on bees and pollination.

Now, the center’s overall goal is to improve the health of honeybee colonies in order to maximize the production of crops that the bees pollinate.

Helping bees

Wearing a white bee suit, DeGrandi-Hoffman hops on a golf cart and drives from her office to the 5.3 acres reserved for honeybee field labs. The huge, round white tents are divided by white nets into smaller rooms, each devoted to a specific study.

In each room, DeGrandi-Hoffman leaves fresh yellow crumbs of pollen made in the lab for “everyone,” as she calls the pollinators in a tone of familiarity.

The health of honeybees is tied closely to human health. Bees pollinate about a third of our crops, mostly the fruits and vegetables in heart-healthy, cancer-preventing and weight-control diets, according to the Agricultural Research Service in the U.S. Department of Agriculture.

But bees are facing challenges.

Varroa mites are harming bees. These parasites attach to a bee’s body and weaken it. A mite infestation can wipe out a whole colony.

“The current hypothesis is that the mites are migratory, dispersed among the bee colonies,” DeGrandi-Hoffman says. She and her colleagues are rearing varroa mites in the lab and exploring ways to control them.

Another challenge is exposure to agrochemicals. Pesticides and fungicides commonly used by farmers disrupt the basic cellular activity in all multicellular organisms.

The effects of the chemicals translate into the bees’ inability to acquire food, according to research by DeGrandi-Hoffman and her colleagues. The bees might not be able to resist parasitic infections. In addition, the chemicals might impair the bees’ brain functions and weaken performance on tasks such as sensory learning and foraging.

Then there is the lack of natural forage that the pollinators need to build and sustain their populations. In some areas, for example, pollutants and pesticides limit the diversity and number of flowering plants, so bees have trouble finding natural nutrition.

In DeGrandi-Hoffman’s research studies, the bees are fed liquid protein and pollen made in the lab. Although not as good as natural pollen, the diet might be able to replace or supplement natural nutrition and improve hive survival.

The bee world as a model

Inside one white room, DeGrandi-Hoffman joins her student aid, Emily Watkins de Jong, a University of Arizona undergraduate studying ecology and evolutionary biology. “We’re going to inspect the eggs on the colonies today in the project determining the impact of pesticides,” says Watkins de Jong as she aims her flashlight at a wooden frame that holds a beehive.

Each bee in the colony is a specialist, collecting pollen from a single species of flower. Year after year, each bee produces hundreds of pounds of wax and honey for the colony’s food supply.

To the researchers, the bees are a model organism: They embody the spirit of collaboration. The researchers are also working with each another to improve the health of honeybees, so they will keep our crops in production.

By the end of the field lab visit, DeGrandi-Hoffman and Watkins de Jong have collected the data they need.

Then, hood off. Bee suit zipper down. Forehead sweat wiped.

“All right. Everyone is fed,” DeGrandi-Hoffman says.

As the bees detect the fresh yellow pollen, more and more of them come out of their colonies. The buzz in the air becomes louder as the feeding and checking routine for the day is finished.

Dieu My Nguyen is a reporter for Arizona Sonora News, a service of the School of Journalism at the University of Arizona. Reach the reporter at


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