Sex dimorphism and hormesis response to polystyrene microplastic exposure in kinematics and metabolism of Drosophila model based on deep learning

The emergence of microplastics (MPs) has become a significant focus of environmental pollution, prompting widespread concern regarding its potential toxicity and impact on the environment and organisms. Recent research indicates notable alterations in insect metabolism and behavioral patterns under the influence of MPs. In this study, the fruit fly (Drosophila melanogaster) was employed as a model organism to investigate the effects of polystyrene microplastics (PS-MPs) on insect behavior, with behavioral parameters used to quantify and assess its toxic effects on fruit flies. Five concentrations (0 g/L, 0.1 g/L, 1 g/L, 10 g/L, 20 g/L) of 5 μm PS-MPs were introduced into the environment, and fruit flies were exposed for 20 days, with subsequent recording of their metabolism and locomotion. In the presence of MPs, both male and female fruit flies exhibited decreasing glucose levels, while protein content decreased in male flies, and irregular gait patterns were observed in both genders. Further quantification of gait parameters revealed that male fruit flies experienced reduced velocity, increased stride length, and larger wing beat angles under microplastic exposure, whereas females exhibited pronounced excitatory effects such as increased velocity and wing beat frequency at lower concentrations, which diminished with higher concentrations, indicating a biphasic response and excitatory effects induced by PS-MPs. These findings highlight the significant impact of PS-MPs on fruit fly metabolism and behavioral patterns, raising concerns regarding the use of PS-MPs.