Natural variation in physicochemical profiles and bacterial communities associated with Aedes aegypti breeding sites and larvae on Guadeloupe and French Guiana

Abstract

Background: Immature stages of Aedes aegypti develop in many man-made aquatic habitats in which mosquito larvae are exposed to physicochemical elements and microorganisms that may influence their life cycle and their ability to transmit human arboviruses. Despite the omnipresence of Ae. aegypti in tropical and subtropical regions, little is known about the natural bacterial communities associated with this mosquito or their relation to the biotic and abiotic characteristics of their aquatic habitats. We comprehensively characterized the physicochemical properties and bacterial microbiome of Ae. aegypti breeding sites and larvae on Guadeloupe and in French Guiana. In addition, we explored whether geographical location, the type of breeding site and physicochemical parameters of the water influenced the microbiota associated with this mosquito species. Method:We used large-scale 16S rRNA gene sequencing of 160 breeding sites and 147 pools of Ae.aegypti larvae from sites widely distributed across Guadeloupe and French Guiana and recorded 13 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 microbiome of water and larvae. Results:We found territory-specific differences in physicochemical properties (dissolved oxygen, conductivity and metal content) and the composition of bacterial communities in Ae. aegypti breeding sites that influenced the relative abundance of several bacteria genera (Methylobacterium, Roseoccocus) on the corresponding larvae. A significant fraction of the bacterial communities identified on Ae. aegypti larvae, dominated by Herbiconiux and Microvirga genera, were consistently enriched in mosquitoes regardless the location. Conclusion:Territory-specific differences observed in the biotic and abiotic properties of Ae. aegypti breeding sites influenced a fraction of the microbial communities of the corresponding larvae, raising concern about the impact of these changes on pathogen transmission by different Ae. aegypti populations. BackgroundAedes aegypti (Diptera: Culicidae) is a mosquito vector of arboviruses such as yellow fever, dengue, 4 chikungunya and Zika that constitute major global health problems and threaten the French overseas territories of Guadeloupe and French Guiana [1,2]. Besides the high susceptibility for these pathogens, this mosquito is a main vector of arboviruses because it is highly anthropophilic and thrives close to humans in urban and peri-urban areas [3,4]. The species breeds mainly in humanmade containers with volumes ranging from a few millilitres to hectolitres, such as drums, plastic buckets, cisterns, flower vases and rubber tyres [4,5].Water quality is critical for the choice of oviposition site for gravid females to ensure successful, complete development of their progeny from larvae to adults [6,7,8]. Females select breeding sites according to biotic and abiotic elements in the water, such as organic matter [8], bacteria [9, 10], phosp...

Multi-Omic Analysis of Symbiotic Bacteria Associated With Aedes aegypti Breeding Sites

“…Several authors have reported the association between Klebsiella and mosquitos, including its detection on eggs, larvae, pupae, adults, and their breeding sites (Gusmão et al, 2010;Chandel et al, 2013;Dada et al, 2014;Yadav et al, 2015;Wang et al, 2018;Hery et al, 2020;Rocha et al, 2021).…”

“…Using high-throughput 16S rRNA amplicon sequencing, Klebsiella has been reported in natural aquatic habitats and in the Ae. aegypti larvae developing there (Hery et al, 2020). Díaz-Nieto et al, 2016 have isolated Klebsiella from all stages of Culex pipiens (for isolation from mosquito gut also Díaz-Nieto, 2014).…”

“…However, several bacterial isolates have been consistently detected in breeding sites, mosquito gut, and other mosquito-associated sources (Guégan et al, 2018). This is the case with Klebsiella, a genus of bacteria frequently reported in mosquitoes and their breeding sites (Gusmão et al, 2010;Chandel et al, 2013;Dada et al, 2014;Yadav et al, 2015;Wang et al, 2018;Hery et al, 2020;Alvarado et al, 2021;Rocha et al, 2021).…”

“…Furthermore, Petri dishes filled with lyophilized Klebsiella resuspended in sterile water have proven to induce oviposition in Culex pipiens (Díaz-Nieto, 2014). This is particularly interesting considering that the water samples collected in natural breeding sites and domestic water storage containers have revealed the presence of Klebsiella (Dada et al, 2014;Hery et al, 2020;Rocha et al, 2021).…”

“…Oviposition-site selection by gravid females depends on water and container properties, with both biotic and abiotic factors shaping the decision on where to lay eggs (Hery et al, 2020). For instance, microbial communities present in water-holding containers have been shown to influence Ae.…”