Effects of polystyrene microplastic ingestion on development, adult fitness, and reproductive success of Culex quinquefasciatus and Anopheles quadrimaculatus

Plastic pollution is an escalating global problem that significantly impacts ecosystems. Because plastics are non-degradable, they accumulate throughout the environment as microplastics (MPs). MPs are a major pollutant in aquatic environments, leading to their inevitable ingestion by a wide range of organisms, including mosquitoes. This laboratory study was conducted to determine the effects of MP ingestion by mosquito larvae on the development, adult fitness, and reproductive success of Culex quinquefasciatus and Anopheles quadrimaculatus. First instar larvae were exposed to different combinations of particle size and concentration of carboxylate-functionalized orange fluorescent polystyrene microspheres; 1 µm and 1000 particles/mL, 1 µm and 100,000 particles/mL, 30 µm and 1000 particles/mL. The results demonstrated that polystyrene MP ingestion impacts larval development, adult fitness (adult size, blood-feeding rate), and reproductive success (fecundity) with differential effects in Cx. quinquefasciatus and An. quadrimaculatus. The study suggests the possibility of particle size and concentration thresholds that significantly impact the life history traits of different mosquito species, potentially influencing population sizes and vectorial capacities. These observations underscore the need for further investigation into the mechanisms and broader implications of plastic pollution on mosquito populations using environmentally realistic MP concentrations.