Palzom Lhamo
Year: 2022
Faculty Advisor: Suzy Strickler
Mentor: Ryan Preble

“Beet armyworm growth assay”

Project Summary:

Our project involves testing the effect of Annonaceous acetogenins from pawpaw trees on the fitness of beet armyworms (Spodoptera exigua). Acetogenins are insecticidal compounds produced by Annonaceous plants including pawpaw trees. By testing this effect, we can determine whether or not acetogenins are defensive against insect herbivores. Unlike previous projects, this project tests the effects of a mixture of acetogenins rather than any single acetogenin. To do this, we did an insect growth assay on beet armyworms. We separated them into four different groups with the following different diets: regular diet, diet and acetogenin extract, diet and lettuce extract, and diet and methanol. Then, we recorded their final weight at the end of the experiment to measure their overall weight gain. The beet armyworms that died before the end were weighed at the time of death for the final weight. As for results, there is insufficient evidence to conclude defensiveness for the 622.9 g/mol acetogenins. Although the mean weight gain was the smallest for the group with acetogenins, each group isn’t statistically different from each other, which is why the results don’t suggest defensiveness. Though our results specifically don’t suggest defensiveness, we did notice that the insects in the treatment group avoided eating the top of the food where the acetogenin extract had been administered. This could be a sign of acetogenins functioning as an antifeedant. Future studies could investigate antifeedant activity or repeat this experiment with more samples and higher acetogenin concentrations for more robust results.

My Experience:

This internship gave me experience that I could have never gotten in school. I’ve been able to work in a real lab and familiarize myself with different tools and experiments. The experiments that I did allowed me to develop crucial lab skills like pipetting, centrifuging, and being patient while your samples are incubating. In addition, having a mentor there was not only incredibly helpful but also made the experience a lot more fun as we got to know each other better. Having a whole research team made it easier for me to reach out and ask for help which was really beneficial throughout the internship. The support I had allowed me to become more confident in my own skills and improved my communication skills as I had to cooperate with many different people. I’ve learned so much more about plant biology, and am excited to continue in the future.