Focusing on fruit flies

For most people, fruit flies are just annoying visitors in the kitchen. We don’t usually think about fruit flies learning or fighting over mates, but Michaela Superson ’13, a neuroscience major, and Jeffrey Paer ’15, a biology major, are looking at these complex behaviors in fruit flies to study brain chemistry and memory.

Superson, who has been working on a senior honors thesis project for the past two semesters, is interested in neurotransmitters, chemicals that relay messages between different cells in the brain. Specially, she is working with dopamine, a neurotransmitter associated with pleasure and reward.

“My senior thesis has provided an excellent introduction to medical research I may conduct in the future,” says Superson, who plans to go to medical school after she graduates from Wheaton. “It has solidified my love of neuroscience and my desire to pursue medicine.”

Paer, who is also interested in a medical career, started out as an assistant for Superson’s thesis project and was soon inspired to start his own research testing memory in fruit flies.

Fruit flies may seem far removed from the ‘people’ that these students want to help, but research on these creatures has broader implications for the workings of the human brain. “Fruit flies are recognized as excellent model organisms for understanding dopamine in general, including its activities in mammals,” explains Professor of Biology Betsey Dyer, advisor to both Superson and Paer. “And flies are, of course, fascinating in their own right.”

Superson’s experimental fruit flies are mutants that produce either too little or too much dopamine. She observes the effects that changes in dopamine can have on courtship behavior, compared to the courtship behavior of ‘normal’ flies. Then, she ‘rescues’ the mutant flies, by adding dopamine or a dopamine inhibitor to restore their dopamine levels to normal.

In the summer before her junior year, Superson studied medicine abroad. The Trustee Scholar traveled to Kunming, China, with Professor Edmund Tong for Wheaton’s “Traditional Chinese Medicine” summer program. She also spent a semester of her junior year at the University of Edinburgh, where she took courses in medical microbiology and the history of medicine.

“Spending those few weeks immersed in the study of Chinese medicinal practices really inspired me to explore the treatment of illnesses from other perspectives,” she says. “It was also really fun to explore medicine in Edinburgh, where so many essential medical developments occurred during the 18th and 19th centuries.”

Paer became interested in working with fruit flies as a freshman in Professor Dyer’s “Genetics” class. “He was so focused and persistent that I would often see him still working in the fly lab long after everyone else had gone to dinner,” Dyer recalls. His work with Superson and a combination of different interests soon inspired him to start his own research.

“Music is my passion,” says Paer, who started playing piano at age four, and since then has played cello, trumpet and several genres of guitar. “My background in music initially inspired me to investigate the effects of music or sound on fruit fly memory.” When he learned that fruit flies can only hear a very limited range of sound—100 to 900 Hertz (a unit of frequency)—he constructed a tiny speaker system with the help of professors John Collins and Jason Goodman, and Physics Department Teaching Assistant Anthony Houser.

Paer had read a published study in which male fruit flies were paired in a small, enclosed ‘fighting arena.’ When paired, one male would assume a dominant role and the other would be subordinate. When paired again 30 minutes later, the flies would assume the same roles, indicating that they had retained a memory of their relationship. But after more than 30 minutes, the roles were often switched, indicating that the flies had forgotten their established dominance relationship. Paer constructed his own tiny, enclosed fighting arena, and plays a sound when pairing up aggressive males, to see if playing the sound later can help flies to recall their status for longer than 30 minutes.

“So far Jeff is getting significant data suggesting that sound indeed is helping the flies to recall their status,” says Dyer. He has found that sound can help fruit flies retain a memory for 40 minutes, and he plans to keep pushing that limit.

Paer’s research provides insight into the learning and behavior in animals, using a creature that could hardly seem more different from us—and yet shares sixty percent of the same genes as humans. He plans to build upon his research for a thesis project in his senior year.

“I love coming up with unique questions based off the literature and pursuing those ideas,” he says.  “The excitement lies in not knowing exactly what will happen.”

—Elizabeth Meyer ’14