Variations in the Bacterial Ecosystems of Mosquito Populations - Haikou and Sanya Cities, Hainan Province, China, 2019.

Abstract

Introduction: This study explores the midgut microbiota of mosquitoes in Haikou and Sanya cities, regions critical for understanding vector-borne disease dynamics in Hainan Province, China. It provides baseline data on microbial composition and examines their potential role in influencing mosquito biology and vector competence, while highlighting the need for further research into their association with vector-borne viral infections.

Methods: Adult mosquitoes were collected using light traps and human bait methods. Species identification was conducted through morphological examination and DNA barcoding using the cytochrome c oxidase subunit 1 gene (cox1). The V3-V4 hypervariable regions of the microbial 16S ribosomal RNA (rRNA) gene were sequenced using high-throughput methods to investigate the midgut microbiota. Statistical analyses, including Alpha and Beta diversity assessments of the sequencing results, were performed using SPSS 21.0 and R version 3.11.

Results: The predominant mosquito species identified were Aedes albopictus, Armigeres subalbatus, and Culex pipiens. Microbiota analysis of 281 midguts revealed that Proteobacteria dominated (85.28%), with significant fractions being Alphaproteobacteria (52.14%), Gammaproteobacteria (29.90%), and Betaproteobacteria (3.22%). Other notable phyla included Firmicutes (6.24%), Actinobacteria (3.81%), and lesser quantities of Thermi, Cyanobacteria, and Bacteroidetes. Significant geographic variation in bacterial communities was observed between Haikou and Sanya (P<0.05), with unique taxa like Thermi and Cyanobacteria identified only in Haikou and Chlamydiae found solely in Sanya. The analysis revealed 204 overlapping species, with 473 unique to Haikou and 64 to Sanya.

Conclusions: This study revealed significant geographic differences in the midgut microbiota of mosquitoes from Haikou and Sanya, providing foundational data for understanding their potential impact on mosquito biology and disease transmission. While the direct relationship between these microbial variations and vector-borne disease dynamics requires further investigation, these findings underscore the importance of mosquito microbiota research as part of broader strategies to mitigate vector-borne disease risks.