Relative contributions of various endogenous and exogenous factors to the mosquito microbiota

Abstract

Background The commensal microbiota of mosquitoes impacts their development, immunity, and competency, and could provide a target for alternative entomological control approaches. However, despite the importance of the mosquito/microbiota interactions, little is known about the relative contribution of endogenous and exogenous factors in shaping the bacterial communities of mosquitoes. Methods We used a high-throughput sequencing-based assay to characterize the bacterial composition and diversity of 665 individual field-caught mosquitoes, as well as their species, genotype at an insecticide resistance locus, blood-meal composition, and the eukaryotic parasites and viruses they carry. We then used these data to rigorously estimate the individual effect of each parameter on the bacterial diversity as well as the relative contribution of each parameter to the microbial composition. Results Overall, multivariate analyses did not reveal any significant contribution of the mosquito species, insecticide resistance, or blood meal to the bacterial composition of the mosquitoes surveyed, and infection with parasites and viruses only contributed very marginally. The main driver of the bacterial diversity was the location at which each mosquito was collected, which explained roughly 20% of the variance observed. Conclusions This analysis shows that when confounding factors are taken into account, the site at which the mosquitoes are collected is the main driver of the bacterial diversity of wild-caught mosquitoes, although further studies will be needed to determine which specific components of the local environment affect bacterial composition. Graphic abstract

Western Kenyan Anopheles gambiae showing intense permethrin resistance harbour distinct microbiota

“…The fixation of the kdr east mutation in the population also precluded further analysis of any associations between kdr alleles and the mosquito microbiota. Indeed, a recent study identified no links between the two [ 42 ]. The authors thus hypothesize that any microbe-mediated mechanism of insecticide resistance would be largely distinct from the mosquito host’s genetics, and likely of a metabolic nature.…”

The Possible Role of Microorganisms in Mosquito Mass Rearing

“…Digestion and detoxification are results of different interactions between the mosquito and the symbiotic microorganisms that can influence the mosquito development and adult nutritional reserves [ 28 ]. Environmental and genetic factors, such as the location of mosquito collection [ 31 , 32 ], the mosquito species [ 33 ], and the rearing conditions [ 34 ], are considered important drivers that shape gut microbiota composition.…”

“…gambiae . At the same time, adult mosquitoes can transmit symbionts in breeding water, thus influencing the microbial composition of the aquatic environment [ 32 , 44 ].…”

Quantification of breeding sites parameters in shaping bacterial communities in Aedes aegypti (Diptera: Culicidae)

“…Additionnally, endosymbionts are inherited from the mother to the egg. Microorganisms thriving in water are recruited by larvae, resulting in more dissimilarity in bacterial community composition in larvae from different collection sites than in larvae collected from the same site 8,9 . Moreover, microbial community structure and evolution are sensitive to biological and physico-chemical properties of the water and the microbial diversity in place 4,7,[10][11][12] .…”

“…Moreover, microbial community structure and evolution are sensitive to biological and physico-chemical properties of the water and the microbial diversity in place 4,7,[10][11][12] . Landuse and geographiccal positions were then associated to microbiota structure in the environment and in mosquitoes, most likely the consequence of a cascade effect 7,8,13,14 .…”