CAC Professor Designs SCEL Project for BIO182 Classes
By Angela Askey, Executive Director Public Relations and Marketing
With the help from an ALRISE Alliance grant received from the National Science Foundation, CAC Professor of Biological Sciences, Dr. Madjid Ghaninia and his students recently completed a SCEL (Student Centered Experiential Learning) project in his BIO182 classes.
There are more than 5.5 million insect species that make up 80% of animal life and insects are dependent upon their olfactory system to survive. The hands-on research activity entitled “New Approaches in Plant Protection Using Insect Olfaction” focused on testing an insect’s olfactory system and how this is like humans. Dr. Ghaninia stated, “The idea was to get students thinking about how insects use their sense of smell (olfaction) to find or avoid certain plants, and how this could be used in environmentally friendly pest control.”
The objectives of the research included teaching students how to collect and analyze experimental data related to insect olfaction, how to determine whether insects’ host-finding behavior is mediated by odor cues, helping students gain an understanding on how insects use olfactory cues to locate host plants, and to introduce environmentally friendly pest management strategies based on insect olfaction.
To begin their research, students used peppermint as a test plant and worked with a Y-shaped olfactometer, a device where an insect is placed at the start of the main arm and must choose between two side arms, each with a different scent. One side had the peppermint plant and the other had plain air. Results showed the insects avoided the peppermint and went toward the blank air, indicating they were repelled by the smell of the plant.
To make sure the insects were reacting to the smell and not how the plant looked, students collected just the headspace chemicals (volatiles) from peppermint. They used an air pump system to pull air through a bag containing the plant, capturing the plant’s smell on a special filter. Then they used a solvent to wash off the chemicals and collected them in a small vial.
The study continued with students using the collected peppermint smell (without the actual plant) in the Y-olfactometer. The insects still avoided it, confirming that it was really the smell, not the appearance, that caused the reaction.
Additionally, the class discussed how the collected chemicals could be analyzed further using gas chromatography (GC), a method that separates and identifies different compounds. This process could assist in determining exactly which part of the peppermint smell repels insects, leading to potential future development of natural repellents or scent-based traps to protect crops.
Dr. Ghaninia provided a detailed protocol, created an Excel spreadsheet for data collection and analysis and ensured students had the materials needed to conduct their research. Students assembled the olfactometer and conducted experiments in a group setting. He explained, “Overall, it was a great project that gave students learning through hands-on experience. They gained a real look into how biology research works, from building the equipment and testing ideas to analyzing data and thinking about real-world uses.” He added, “The students were engaged, reflecting the spirit of what SCEL is all about.”
Based on the success of the insect testing this spring, Dr. Ghaninia will be integrating the “New Approaches in Plant Protection Using Insect Olfaction” project into future BIO182 classes.
