The Effects of Post-Consumer Waste Polystyrene on the Rate of Mealworm Consumption

Polymer debris is estimated to pollute approximately 40% of the planet’s oceans, posing a great threat to marine ecosystems globally . A study released by Stanford scientists Yang et al. in 2015 found that mealworms consume and biodegrade expanded polystyrene (EPS), or Styrofoam, a polymer that is responsible for a large percentage of ocean pollution. However, this study only tested the mealworm consumption rates for virgin white EPS. If mealworms are to be used by consumers or the recycling industry to biodegrade EPS pollution, post-consumer use and colored EPS must be tested. This study investigates these new variables by testing different types of post-consumer EPS (highly pigmented, white, high-density, and low-density) to determine if mealworm consumption is affected. The measured results of 3.79 mg EPS consumed per mealworm life cycle for high-density EPS confirm Yang et al.’s measurements of 3.60 mg EPS per mealworm life cycle for the consumption rate of white, high-density EPS. Furthermore, the results indicate that whether the EPS was virgin or post-consumer did not affect the consumption rates. It was found that low-density EPS is consumed at a 56% higher rate than high-density EPS. Consumption rates for non-waxy and white EPS were slightly higher than those of waxy and colored EPS respectively but were within one standard deviation of difference. From this data we can calculate that it would take 4,720 mealworms to consume 17 grams of EPS, equivalent to a single serving clamshell container, consumed over the course of the mealworms’ 30-day lifespan.