Combined Effects of Nano- and Microplastics, Perfluorooctane Sulfonic Acid (pfos), and Temperature on the Development of Aedes Albopictus

Mosquitoes develop in freshwater habitats where they are exposed to emerging environmental contaminants such as nano- and microplastics (NMPs) and the “forever chemical” perfluorooctane sulfonic acid (PFOS), both of which can alter development and survival. In immature Aedes albopictus mosquitoes, NMPs disrupt growth and emergence, while PFOS delays development and increases mortality; however, their combined effects across temperatures remain poorly understood. This thesis examined how NMPs, PFOS, and temperature interact to influence development, sex ratio, and mortality in Ae. albopictus. Aim 1 showed that only the smallest NMPs (0.2 µm) delayed emergence, whereas larger particles (2 µm and 20 µm) produced no significant effects on emergence or sex ratio. In contrast, higher NMP concentrations significantly increased adult mortality, with clear concentration effects and treatment interactions, indicating lethal impacts despite largely stable emergence. Aim 2 demonstrated that combined exposure to NMPs and PFOS significantly reduced emergence and increased adult mortality relative to single contaminant treatments. Mortality was highest in the 2 µm + PFOS and 20 µm + PFOS treatments, indicating synergistic toxicity and reduced female emergence compared with PFOS alone. Aim 3 showed that elevated temperature significantly affected emergence, sex ratio, and adult mortality, and modified NMP and PFOS effects depending on particle size and treatment combination. Overall, NMP and PFOS related effects on Ae. albopictus development and survival were context dependent, varying with particle size, concentration, and temperature, highlighting the importance of considering multiple stressors when evaluating contaminant risks to mosquito populations globally.