Extracellular microbes are required for mosquito development even in the presence of Wolbachia.

Wolbachia, an endosymbiotic bacterium infecting a wide array of invertebrates, has gained attention for its potential in vector control. Its capacity to colonise host populations primarily relies on vertical transmission and reproductive manipulation in arthropods. This endosymbiont is additionally mutualistic in some hosts, across several Wolbachia supergroups; notably, in nematodes and, as recently demonstrated, in planthoppers and bedbugs, it functions as an essential nutritional symbiont by providing vitamins to its host.

Population genomics of , the principal South American malaria vector mosquito.

Malaria in South America remains a serious public health problem. () is the most important malaria vector across tropical Latin America. Vector-targeted disease control efforts require a thorough understanding of mosquito demographic and evolutionary patterns.

Nutritional sex-specificity on bacterial metabolites during mosquito (Aedes aegypti) development leads to adult sex-ratio distortion.

Mosquitoes rely on their microbiota for B vitamin synthesis. We previously found that Aedes aegypti third-instar larvae cleared of their microbiota were impaired in their development, notably due to a lack of folic acid (vitamin B9). In this study, we found that diet supplementation using a cocktail of seven B vitamins did not improve mosquito developmental success, but rather had a significant impact on the sex-ratio of the resulting adults, with an enrichment of female mosquitoes emerging from B vitamin-treated larvae.

Insects and microbes: best friends from the nursery.

Insects host microbes and interact with them throughout their life cycle. This microbiota is an important, if not essential, partner participating in many aspects of insect physiology. Recent omics studies have contributed to considerable advances in the current understanding of the molecular implications of microbiota during insect development.

Using capillary electrophoresis to identify Anopheline species in routine sampling sites.

In the genus, various mosquito species are able to transmit the parasites responsible for malaria, while others are non-vectors. In an effort to better understand the biology of species and to quantify transmission risk in an area, the identification of mosquito species collected in the field is an essential but problematic task. Morphological identification requires expertise and cannot be checked after processing samples in a destructive treatment, while sequencing of numerous samples is costly.

Three new species of Culex (Melanoconion) (Diptera: Culicidae) from French Guiana based on morphological and molecular data.

Culex mosquitoes of the subgenus Melanoconion Theobald, 1903 of the genus Culex Linnaeus, 1758 include numerous species recognized as vectors of viruses affecting humans. This subgenus is the most speciose among the entire mosquito fauna of the Americas. Despite decades of taxonomic research, many species remain undiscovered, especially in the Amazonian biome.

Involvement of Microbiota in Insect Physiology: Focus on B Vitamins.

Insects are highly successful in colonizing a wide spectrum of ecological niches and in feeding on a wide diversity of diets. This is notably linked to their capacity to get from their microbiota any essential component lacking in the diet such as vitamins and amino acids. Over a century of research based on dietary analysis, antimicrobial treatment, gnotobiotic rearing, and culture-independent microbe detection progressively generated a wealth of information about the role of the microbiota in specific aspects of insect fitness.

Analyzing gut microbiota composition in individual mosquitoes after experimental treatment.

The microbiota of mosquitoes influences malaria transmission. Antibiotics ingested during a blood meal impact the mosquito microbiome and malaria transmission, with substantial differences between drugs. Here, we assessed if amoxicillin affects the gut mosquito microbiota We collected larvae in Burkina Faso, kept them in semi-field conditions, and offered a blood meal to adult females.

Linking microbiota composition with antimalarial antibody response.

Microbiota composition recently arose as a factor correlating with malaria infection. Mandal et al. showed, via cecal transplant and antibacterial treatment, that the mouse microbiota modulates parasitemia by affecting spleen germinal centers where B cells are matured.

The Effect of Secondary Metabolites Produced by on and Its Microbiota.

is a bacterial species widely found in the environment, which very efficiently colonizes mosquitoes. In this study, we isolated a red-pigmented strain from our mosquito colony (called VA). This red pigmentation is caused by the production of prodigiosin, a molecule with antibacterial properties.

Production of germ-free mosquitoes via transient colonisation allows stage-specific investigation of host-microbiota interactions.

The mosquito microbiota impacts the physiology of its host and is essential for normal larval development, thereby influencing transmission of vector-borne pathogens. Germ-free mosquitoes generated with current methods show larval stunting and developmental deficits. Therefore, functional studies of the mosquito microbiota have so far mostly been limited to antibiotic treatments of emerging adults.

Antibiotic Treatment in Affects Carbon and Nitrogen Metabolism.

The mosquito microbiota reduces the vector competence of to and affects host fitness; it is therefore considered as a potential target to reduce malaria transmission. While immune induction, secretion of antimicrobials and metabolic competition are three typical mechanisms of microbiota-mediated protection against invasive pathogens in mammals, the involvement of metabolic competition or mutualism in mosquito-microbiota and microbiota- interactions has not been investigated. Here, we describe a metabolome analysis of the midgut of provided with a sugar-meal or a non-infectious blood-meal, under conventional or antibiotic-treated conditions.

Functional analysis of the three major PGRPLC isoforms in the midgut of the malaria mosquito Anopheles coluzzii.

Peptidoglycan recognition proteins (PGRPs) constitute the primary means of bacterial recognition in insects. Recent work in the model organism Drosophila has revealed the mechanisms by which the complement of PGRPs refine the sensitivity of different tissues to bacterial elicitors, permitting the persistence of commensal bacteria in the gut whilst maintaining vigilance against bacterial infection. Here, we use in vivo knockdowns and in vitro pull-down assays to investigate the role of the three major isoforms of the transmembrane receptor of the Imd pathway, PGRPLC, in basal immunity in the Anopheles coluzzii mosquito midgut.

The tripartite interactions between the mosquito, its microbiota and Plasmodium.

The microbiota of Anopheles mosquitoes interferes with mosquito infection by Plasmodium and influences mosquito fitness, therefore affecting vectorial capacity. This natural barrier to malaria transmission has been regarded with growing interest in the last 20 years, as it may be a source of new transmission-blocking strategies. The last decade has seen tremendous progress in the functional characterisation of the tripartite interactions between the mosquito, its microbiota and Plasmodium parasites.

[Mosquito microbiota and its influence on disease vectorial transmission].

Mosquitoes (Diptera: Culicidae) are found worldwide. Around 100 among 3500 mosquito species are known to be vectors of parasites and viruses, responsible for infectious diseases including malaria and dengue. Mosquitoes host diverse microbial communities that influence disease transmission, either by direct interference or via affecting host immunity and physiology.

A Swiss Army Knife to Cut Malaria Transmission.

The mosquito microbiota is known to naturally limit malaria transmission, acting directly on parasites and via effects on mosquito immunity and fitness. Using genetically modified bacteria and mosquitoes, two studies uncover new potential of this multipotent prospective tool to reduce disease transmission.

Microbiota-induced peritrophic matrix regulates midgut homeostasis and prevents systemic infection of malaria vector mosquitoes.

Manipulation of the mosquito gut microbiota can lay the foundations for novel methods for disease transmission control. Mosquito blood feeding triggers a significant, transient increase of the gut microbiota, but little is known about the mechanisms by which the mosquito controls this bacterial growth whilst limiting inflammation of the gut epithelium. Here, we investigate the gut epithelial response to the changing microbiota load upon blood feeding in the malaria vector Anopheles coluzzii.

The Peptidoglycan Recognition Proteins PGRPLA and PGRPLB Regulate Anopheles Immunity to Bacteria and Affect Infection by Plasmodium.

Peptidoglycan recognition proteins (PGRPs) form a family of immune regulators that is conserved from insects to mammals. In the malaria vector mosquito Anophelescoluzzii, the peptidoglycan receptor PGRPLC activates the immune-deficiency (Imd) pathway limiting both the microbiota load and Plasmodium infection. Here, we carried out an RNA interference screen to examine the role of all 7 Anopheles PGRPs in infections with Plasmodium berghei and P.

Larval diet affects mosquito development and permissiveness to Plasmodium infection.

The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii.

Differential Effects of Azithromycin, Doxycycline, and Cotrimoxazole in Ingested Blood on the Vectorial Capacity of Malaria Mosquitoes.

Background.  The gut microbiota of malaria vector mosquitoes grows after a blood meal and limits Plasmodium infection. We previously showed that penicillin and streptomycin in the ingested blood affect bacterial growth and positively impact mosquito survival and permissiveness to Plasmodium.

Seasonality and Locality Affect the Diversity of Anopheles gambiae and Anopheles coluzzii Midgut Microbiota from Ghana.

Symbiotic bacteria can have important implications in the development and competence of disease vectors. In Anopheles mosquitoes, the composition of the midgut microbiota is largely influenced by the larval breeding site, but the exact factors shaping this composition are currently unknown. Here, we examined whether the proximity to urban areas and seasons have an impact on the midgut microbial community of the two major malaria vectors in Africa, An.

Antibiotics in ingested human blood affect the mosquito microbiota and capacity to transmit malaria.

Malaria reduction is most efficiently achieved by vector control whereby human populations at high risk of contracting and transmitting the disease are protected from mosquito bites. Here, we identify the presence of antibiotics in the blood of malaria-infected people as a new risk of increasing disease transmission. We show that antibiotics in ingested blood enhance the susceptibility of Anopheles gambiae mosquitoes to malaria infection by disturbing their gut microbiota.

Functional analysis of PGRP-LA in Drosophila immunity.

PeptidoGlycan Recognition Proteins (PGRPs) are key regulators of the insect innate antibacterial response. Even if they have been intensively studied, some of them have yet unknown functions. Here, we present a functional analysis of PGRP-LA, an as yet uncharacterized Drosophila PGRP.

Long-range activation of systemic immunity through peptidoglycan diffusion in Drosophila.

The systemic immune response of Drosophila is known to be induced both by septic injury and by oral infection with certain bacteria, and is characterized by the secretion of antimicrobial peptides (AMPs) into the haemolymph. To investigate other possible routes of bacterial infection, we deposited Erwinia carotovora (Ecc15) on various sites of the cuticle and monitored the immune response via expression of the AMP gene Diptericin. A strong response was observed to deposition on the genital plate of males (up to 20% of a septic injury response), but not females.