An Enzyme Assay with Evolutionary Implications: You Are What You Eat! The Effect of Food Source on Activity of Esterases in Bean Beetles

 

Fardad Firooznia, Avajé Jackson, Mohammad I. Khan, & Hector Fermin

Tested Studies in Laboratory Teaching, 2019, Volume 40

Abstract

Here we present a multi-session, investigative enzyme lab using detoxification enzymes that have a potential role in the development of insecticide resistance in insect pests. Using the bean beetle (Callosobruchus maculatus) as a model organism, students will try to determine whether food source affects activity levels of detoxification esterase enzymes in bean beetles, which would have implications for the resistance of these pests to insecticides. The students will a) learn about the life cycle of the beetles, how to differentiate sexes, and how to culture the beetles, b) gain experience in designing a study using basic biochemical techniques such as standard curves and colorimetric assays, and collecting, analyzing, and reporting data for such a study, and c) discuss the interplay between natural selection, leading to the evolution of defensive chemicals in plants and detoxification enzymes in animals, with agroecology, leading to resistance to insecticides.

Keywords:  Biochemistry, enzyme assay, bean beetle, Inquiry-based learning, detoxification enzymes, evolutionary arms race, insecticide resistance

The Ohio State University (2018)