Developmental Transfer of Microplastic Particles from Larval to Adult Stages of the Drone Fly Eristalis tenax

Plastic pollution has become a critical environmental issue, with vast amounts of plastic waste accumulating in aquatic and terrestrial ecosystems. Plastic pollution poses significant risks to biodiversity by introducing toxic chemicals and disrupting biological functions. The drone fly, Eristalis tenax, is perhaps the most globally widespread hoverfly. This success is aided by its development as a rat-tailed maggot in a wide array of aquatic environments where it feeds on decaying organic matter. As an adult, E. tenax is a vital pollinator, visiting a wide range of crops and wild plants, and has been shown to vector pollen over hundreds of kilometres during seasonal migrations. Exposure to microplastics during larval stages has the potential to alter the provision of these ecosystem services and to provide a route for the long-distance vectoring of microplastics. To investigate this, we rear E. tenax in water contaminated with different concentrations of microplastic particles. We show that these plastics are retained in the gut from larval through to pupal to adult developmental stages. This contamination resulted in reductions of 33% and 60% in pupal and adult weight when exposed to the highest concentrations of microplastic particles but resulted in no detectable effects on mortality or developmental length. Our results demonstrate the potential for the vectoring of microplastics by this highly mobile species. However, the associated reductions in body size likely have profound consequences for movement capability in terms of foraging and migration and should be further investigated for their impact on ecosystem service provision.