Microplastic pollution differentially affects development of disease-vectoring Aedes and Culex mosquitoes

Plastic in the form of microplastic particles (MPs) is now recognized as a major pollutant of unknown consequences in aquatic habitats. Mosquitoes, with aquatic eggs, larvae, and pupae, are likely to encounter microplastic, particularly those species that are abundant in close proximity to human development, including those that vector human and animal disease. We examined the effects of polyethylene MPs, the most common microplastic documented in environmental samples, on the development and survival of the mosquitoes Aedes albopictus and Culex quinquefasciatus. In laboratory egg-laying and larval development container environments similar to those used by both species in the field, a mix of 1-53 µm MPs at concentrations of 60, 600, and 6000 MP ml^-1 increased early instar larval mortality in both species relative to control treatments. A significant difference was found in the response of each species to microplastic at the lowest microplastic concentration tested, with Cx. quinquefasciatus survival equivalent to that in control conditions but with Ae. albopictus larvae mortality elevated to 37% within 48 h. These results differ from those of previous studies in which larvae were only exposed to MPs during the last aquatic instar stage and from which it was concluded that microplastic was ontogenically transferred without negatively affecting development. Increasing plastic pollutant concentrations could therefore act as selective pressures on aquatic larvae and ultimately influence outcomes of ecological interactions among mosquito vector populations.