McKelvey School of Engineering

Studying how serotonin alters locust’s sense of smell

WashU researchers studied how serotonin alters a locust’s sense of smell. (Photo: Raman lab)

Researchers at Washington University in St. Louis have spent the better part of the decade studying the ins and outs of how locusts smell, including how odors affect the insect’s behavior.

In research recently published in eLife, Barani Raman, PhD, a professor of biomedical engineering at the McKelvey School of Engineering, starts to map out just how olfactory circuits are altered in driving different behavior in locusts. Neuromodulator serotonin is a key factor in that behavior including how locusts can go from being a “loner” to “gregarious” — otherwise known as swarming phase.

“The same organism can exist in two different states — one is destructive, and one is shy and introverted,” Raman said.

Raman and PhD student Yelyzaveta Bessonova wanted to investigate how serotonin affects the part of the neural circuit in the locust brain that senses olfactory cues and drives appropriate behavioral responses. The more researchers understand how sensory signals are processed, the easier it will be to control and prevent locusts from swarming. From an engineering point of view, understanding this biological system can inspire solutions for odor detection in dangerous and toxic environments.

To understand how the same odor can trigger different behavior, imagine how the smell of freshly baked cookies might drive a quest to the kitchen when someone is hungry. But, after consumption of a few cookies, that same smell might be ignored or even induce disgust, Raman said.

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