From metabolism to lifespan trade-offs: polyethylene microplastics induce circadian disruption and sex-specific aging in Drosophila melanogaster

Microplastics (MPs), particularly polyethylene microplastics (PE-MPs), are increasingly recognized as contaminants in both aquatic and terrestrial environments. However, the ecological impacts of PE-MPs on terrestrial organisms remain underexplored. This study investigates the physiological and behavioral effects of PE-MPs exposure in the terrestrial model organism Drosophila melanogaster, shedding light on the potential risks posed by PE-MPs in land-based ecosystems. After exposing the fruit flies to different concentrations of PE-MPs for 20 days, we assessed several physiological biomarkers, including spontaneous behavioral activity, starvation resistance, metabolic biomarkers, and lifespan. Our findings indicate that PE-MPs exposure significantly affects fruit fly physiology, with increased spontaneous activity, decreased starvation resistance, and reduced triglyceride (TG) and protein levels (in males), reflecting disruption of metabolic processes. While PE-MPs did not affect female reproductive capacity, they did result in sex-specific impacts on lifespan, with male fruit flies showing a significant reduction in both mean and median lifespan at higher PE-MPs concentrations. These results highlight the need to consider the sex-dependent nature of PE-MPs toxicity when assessing their ecological risks. This study contributes new insights into the potential for PE-MPs to disrupt terrestrial ecosystems and underscores the importance of investigating the effects of microplastics on terrestrial invertebrates, providing a foundation for future ecotoxicological research.