Plastic mulching films are commonly used in agriculture to improve crop growth, but over time, they can break down into tiny particles called microplastics (MPs), which end up in the soil. While we know these particles can accumulate, there is still limited information about how they affect soil insects over the long term.
In this study, researchers looked at how microplastics from two types of mulching films—one made from traditional plastic (polyethylene, or PE) and the other from a biodegradable material (a starch-PBAT blend)—influenced the growth and health of mealworms (Tenebrio molitor) over two generations. The insects were fed food mixed with different concentrations of microplastics, ranging from very low to relatively high levels.
The results showed that neither type of plastic affected the mealworms’ ability to survive or develop over the full course of the study (12 weeks for the first generation and 9 weeks for the second). However, some changes were observed in their growth and moulting patterns. In the first generation, high levels of PE microplastics slowed down the larvae’s growth and moulting. Interestingly, in the second generation, high levels of PBAT microplastics actually promoted growth, possibly because the mealworms were able to partially digest the biodegradable plastic.
Overall, the study suggests that microplastics from agricultural films are unlikely to harm mealworms at the levels typically found in soil, but very high concentrations may affect their development.
Read the full study here: https://www.sciencedirect.com/science/article/pii/S0048969724046382?via%3Dihub