F&M student finds honeybees can be trained to avoid herbicides

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LANCASTER, Pa. (from Franklin & Marshall College) — Senior Eric Mellis ’13 found himself pondering an intriguing question: Could honeybees be trained to avoid plants treated with herbicides?

With the help of Sarah Dawson, director of the Wohlsen Center for the Sustainable Environment at F&M, Mellis designed an independent study to find out. The short answer: Yes, they can be. And that could have important implications for bees and humans.

“Synthetic chemicals are largely implicated in the loss of honeybees,” Mellis said. “Training bees to avoid them locally could lead to research to implement such behavior on a larger scale.”

As a special studies major, Mellis became interested in herbicides, which are chemicals designed to destroy or stunt the growth of unwanted plants, as part of his exploration of a mysterious phenomenon that is threatening bee populations worldwide. The phenomenon, Colony Collapse Disorder, has become a major focus of the United States Environmental Protection Agency, as it causes the sudden disappearance of worker bees from a beehive, leading to the “collapse” of an entire bee colony.

The consequences of colony collapse are far-reaching. Honeybees pollinate the flowers that bloom into much of the nation’s food supply, according to the Federal Drug Administration, which estimates that bee pollination adds $15 billion in value to the agriculture industry each year.

Mellis found that it was possible to train bees to avoid plants that had been sprayed with herbicides, but the bees would not avoid herbicides naturally, he said. This was a significant finding in his research because pesticides, in particular neonicotinoids (insecticides that are chemically related to nicotine) are used extensively in agriculture and have been implicated in Colony Collapse Disorder. Therefore, teaching bees to avoid synthetic chemicals might help their hives to persist.

As part of his experiment, Mellis trained a group of bees to avoid an herbicide, Roundup, using negative reinforcement. He created an association between herbicides and water, which bees naturally avoid because they associate it with a lost foraging opportunity, placing cotton balls sprayed with the herbicide next to a Petri dish filled with water. The bees steered clear of both the water and the herbicide. Later, he sprayed the herbicide on some flowers but not on others, and the bees trained to avoid herbicides foraged on the flowers that had not been sprayed. Bees in the control group did not distinguish between the treated and untreated flowers.

Mellis’ project expands on the research of a former F&M student, Veronica Thomas ’11, who as a biological foundations of behavior major originally proposed the idea of a honeybee apiary on the College’s Baker Campus. Similar to Mellis, Thomas also collaborated with Dawson, with her project exploring how bees could be trained to prefer organic plants and to avoid pesticide-treated plants.

“Veronica Thomas’ research had shown that we could teach bees to forage on organic plants, but that required an application of a new scent to the crops,” Dawson said. “Teaching bees to go away from a chemical — like an herbicide — that has already been applied to plants makes the process less complex.”

Mellis chose to train the bees to avoid plants treated with herbicides rather than to seek out organic plants because the training process was simpler, and he hoped to reach conclusions quickly and thus help to deter colony collapse, he said.

His research could lead to additional research opportunities for F&M students and provide a further understanding of the harmful effects of the disorder, Dawson said. She hopes to work with new students to expand the research to several farms with larger apiaries and to test whether pesticides may be detected in other materials such as honey.