Natural Variation in Physicochemical Profiles and Bacterial Communities Associated with Aedes aegypti Breeding Sites and Larvae on Guadeloupe and French Guiana

Lyza Hery,Christelle Delannay,Amandine Guidez,Josiann Normandeau-Guimond,Philippe Constant,Daniella Goindin,Joel Gustave,Audrey-Anne Durand,Isabelle Dusfour,Grégory Legrave,Sebastien Breurec,Claude Guertin,Jean Issaly,Yann Reynaud,Anubis Vega-Rúa,Stéphanie Raffestin

doi:10.1007/s00248-020-01544-3

Abstract

Aedes aegypti develop in aquatic habitats in which mosquito larvae are exposed to physicochemical elements and microorganisms that may influence their life cycle and their ability to transmit arboviruses. Little is known about the natural bacterial communities associated with A. aegypti or their relation to the biotic and abiotic characteristics of their aquatic habitats. We characterized the physicochemical properties and bacterial microbiota of A. aegypti breeding sites and larvae on Guadeloupe and in French Guiana. In addition, we explored whether geographic location, the type of breeding site and physicochemical parameters influenced the microbiota associated with this mosquito species. We used large-scale 16S rRNA gene sequencing of 160 breeding sites and 147 pools of A. aegypti larvae and recorded 12 physicochemical parameters at the sampled breeding sites. Ordination plots and multiple linear regression were used to assess the influence of environmental factors on the bacterial microbiota of water and larvae. We found territory-specific differences in physicochemical properties (dissolved oxygen, conductivity) and the composition of bacterial communities in A. aegypti breeding sites that influenced the relative abundance of several bacteria genera (e.g., Methylobacterium, Roseoccocus) on the corresponding larvae. A significant fraction of the bacterial communities identified on larvae, dominated by Herbiconiux and Microvirga genera, were consistently enriched in mosquitoes regardless the location. In conclusion, territory-specific differences observed in the biotic and abiotic properties of A. aegypti breeding sites raise concern about the impact of these changes on pathogen transmission by different A. aegypti populations.

Highlights

Aedes aegypti (Diptera: Culicidae) is a mosquito vector of arboviruses such as dengue, chikungunya and Zika that constitute major global health problems and threaten the French overseas territories of Guadeloupe and French Guiana [1, 2]
We explored whether features of larval habitats, including geographical location, type of breeding site and the physicochemical parameters of the water influence the variation in the bacterial microbiota associated with this mosquito species
Differences were observed between the two territories in levels of conductivity, dissolved oxygen, Ca and Mg in breeding sites, which were higher on Guadeloupe, and in turbidity, chemical oxygen demand (COD), Cu, Fe and Zn content, which were higher in French Guiana

Summary

Introduction

Aedes aegypti (Diptera: Culicidae) is a mosquito vector of arboviruses such as dengue, chikungunya and Zika that constitute major global health problems and threaten the French overseas territories of Guadeloupe and French Guiana [1, 2]. Females select breeding sites according to biotic and abiotic elements in the water, such as organic matter [8], bacteria [9, 10], phosphate, ammonia and potassium [11,12,13], which are known to be closely related to the abundance of larvae and adults in the field [13,14,15] Larvae in their aquatic habitats rely on bacteria communities and organic matter whose composition is highly variable depending on environmental fluctuations [16, 17]. The complexity and plasticity of A. aegypti–bacteria interactions in breeding sites are still poorly understood, and it is unclear how the bacterial communities in A. aegypti breeding sites are structured in natural settings at different geographical scales

Results

Discussion

Conclusion