Accumulation of microplastics and anthropogenic fibers in natural populations of blood-sucking mosquitoes of the genus Aedes in the environs of Tomsk (Western Siberia, Russia)

Abstract

The content of microplastics (MPs) was monitored in natural populations of blood-sucking mosquitoes of the genus Aedes (Meigen, 1818) at different mosquito life cycle stages in the environs of Tomsk (Western Siberia, Russia) across various biotopes (meadow swamps, forest bogs, sphagnum bogs) for three years (2021–2023). A total of 990 mosquitoes were analyzed for MP content. The detected MPs varied in shape and size, ranging from 0.1 to 1 mm. The average number of MPs per mosquito individual increased from 0.012 ± 0.003 in 2021 to 0.191 ± 0.087 in 2023. The MP content increased from larval stage I to larval stage III, decreased at stage IV, and then decreased at pupal and imago stages. The highest MP content was recorded in mosquitoes from sphagnum bogs, while the lowest one was found in insects from meadow swamps. No statistically significant differences were revealed across biotopes. Black fragments and fibers <0.5 mm in size were predominant. The analysis revealed a general trend in which the number of MPs increases annually, particularly small black fragments (tire and road wear particles). This increase may be attributed to the proximity of roads that contribute to MP pollution in nearby water bodies, as well as degradation of synthetic textiles resulting in the release of MPs and anthropogenic fibers via sewage effluents. The obtained data indicate a wide distribution of MPs in natural populations of Aedes mosquitoes and confirm the urgent need for further research into the effect of MPs on their biology and the role of these insects as pollution indicators.