Biodegradation of commercial expanded polystyrene foam (EPS) and pure EPS foams was investigated by Tahroudi et al. (2025) with a single source of mealworms (larvae of Tenebrio molitor) from Australia. They claimed that EPS is not chemically degraded by yellow mealworms because degradation of the additive was solely responsible for the molecular weight reduction of commercial EPS, and pure EPS was essentially unaffected by passage through the digestive tract. They found that both pure and commercial EPS diets failed to sustain mealworm growth, and survival rates decreased, which has been documented by other researchers. Our comments are that the conclusions of Tahroudi et al. i.e. “expanded polystyrene is not chemically degraded by mealworms” were not fully supported by their data and key evidence was overlooked due to methodological limitations and other weaknesses, including an incomplete mass balance, misinterpretation of GPC and FTIR data, and underutilization of analytical tools established for assessment of plastic degradation. Published results, including our own, demonstrated polystyrene biodegradation of both commercial foams and high-purity PS products by mealworms from various sources. Degradation capabilities varied by mealworm strain, larval age, physical and chemical properties of PS products, nutrients, and environmental factors, making broad generalizations problematic. We also call for microbiome, transcriptome and metabolome analyses to better understand enzymatic contributions to plastic biodegradation. Given the growing body of evidence supporting mealworm-mediated plastic degradation, we highly recommend a more comprehensive approach to assessing plastic biodegradation, incorporating long-term studies, CO₂ release, advanced analytical techniques (¹H NMR, GC-MS, py-GC/MS, δ¹³C, XPS etc.) with mass balance calculations associated with gut microbiome, transcriptome and metabolome. Comparison of mealworms from different sources, nutrition history and feeding conditions, and instar stage would provide new insights into the mealworm-mediated plastic degradation.