Microplastic exposure alters immune-related gene expression in Culex quinquefasciatus mosquitoes and larval microbiota diversity
- 1UMR MIVEGEC, University of Montpellier, IRD, CNRS - Montpellier, France
Abstract
Background: Microplastics have been detected in many freshwater ecosystems, including stagnant waters where mosquito larvae develop. Larvae are therefore exposed to microplastic pollution, which may affect their life history traits or microbiota along with immune gene expression. However, these effects have never been tested in mosquitoes, despite their major public health importance as vectors of numerous pathogens. Method: We exposed mosquito larvae, from hatching to adult emergence, to four concentrations of polyethylene microplastics (MPs): 0, 60, 200, and 600 MPs/mL. Fourth-instar larvae and newly emerged adult females were collected for each treatment. To investigate the effects of MPs on gene expression and bacterial microbiota, RNA sequencing and 16S metabarcoding approaches were performed on three biological replicates for each developmental stage. Results: Microplastic exposure induced a non-monotonic dose-dependent transcriptomic response. In larvae, only a limited number of genes were differentially expressed (five to eight per concentration), with immune-related genes downregulated at both low and high concentrations. In adult females, the intermediate concentration (200 MPs/mL) elicited the strongest response with 14 differentially expressed genes (DEGs). Regarding the microbiota, microplastic exposure reduced bacterial diversity in larvae, with the lowest diversity observed at the highest concentration. However, no significant changes were detected in the microbiota of adult females. Conclusion: Overall, this study shows that adult females are affected by larval exposure to MPs (i.e. differential expression in immune-related genes) and warrants further studies in this field. This includes: 1) investigating further the effects of MPs on mosquitoes' populations (e.g. through multi-generational studies), 2) gaining more environmentally relevant knowledge on MP effects (i.e. using MPs with a biofilm and/or adsorbed pollutants) and 3) focusing on the effects of MPs on mosquitoes' vectorial capacities.
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BibTeX
@misc{tchatakoura2026microplastic,
title = {{Microplastic exposure alters immune-related gene expression in Culex quinquefasciatus mosquitoes and larval microbiota diversity}},
author = {A. Tchatakoura and M. Buysse and M.-L. Setier-Rio and O. Roux and C. Loiseau and A. Aviles},
howpublished = {bioRxiv},
year = {2026},
month = aug,
doi = {10.64898/2026.08.27.747521},
url = {https://www.biorxiv.org/content/10.64898/2026.08.27.747521v2},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Microplastic exposure alters immune-related gene expression in Culex quinquefasciatus mosquitoes and larval microbiota diversity
AU - A. Tchatakoura
AU - M. Buysse
AU - M.-L. Setier-Rio
AU - O. Roux
AU - C. Loiseau
AU - A. Aviles
PY - 2026
DA - 2026/08/27
PB - bioRxiv
DO - 10.64898/2026.08.27.747521
UR - https://www.biorxiv.org/content/10.64898/2026.08.27.747521v2
AB - Background: Microplastics have been detected in many freshwater ecosystems, including stagnant waters where mosquito larvae develop. Larvae are therefore exposed to microplastic pollution, which may affect their life history traits or microbiota along with immune gene expression. However, these effects have never been tested in mosquitoes, despite their major public health importance as vectors of numerous pathogens. Method: We exposed mosquito larvae, from hatching to adult emergence, to four concentrations of polyethylene microplastics (MPs): 0, 60, 200, and 600 MPs/mL. Fourth-instar larvae and newly emerged adult females were collected for each treatment. To investigate the effects of MPs on gene expression and bacterial microbiota, RNA sequencing and 16S metabarcoding approaches were performed on three biological replicates for each developmental stage. Results: Microplastic exposure induced a non-monotonic dose-dependent transcriptomic response. In larvae, only a limited number of genes were differentially expressed (five to eight per concentration), with immune-related genes downregulated at both low and high concentrations. In adult females, the intermediate concentration (200 MPs/mL) elicited the strongest response with 14 differentially expressed genes (DEGs). Regarding the microbiota, microplastic exposure reduced bacterial diversity in larvae, with the lowest diversity observed at the highest concentration. However, no significant changes were detected in the microbiota of adult females. Conclusion: Overall, this study shows that adult females are affected by larval exposure to MPs (i.e. differential expression in immune-related genes) and warrants further studies in this field. This includes: 1) investigating further the effects of MPs on mosquitoes' populations (e.g. through multi-generational studies), 2) gaining more environmentally relevant knowledge on MP effects (i.e. using MPs with a biofilm and/or adsorbed pollutants) and 3) focusing on the effects of MPs on mosquitoes' vectorial capacities.
ER -