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Abstract Background The biological larvicide Bacillus thuringiensis subsp. israelensis (Bti) represents a safe and effective alternative to chemical insecticides for mosquito control. Efficient control of mosquitoes implicates continuous and extensive application of Bti. This massive use of Bti imposes strong selective pressure, but the complex mode of action of the numerous synergistic Bti endotoxins lower the risk of the emergence of resistance. Although resistance to Bti has not been identified at the population level in nature, some larvae can survive Bti exposure, suggesting tolerance mechanisms. Here we investigated whether Bti-tolerant Aedes albopictus larvae experience any fitness costs. We also studied how this tolerance affects different aspects of the phenotype of the emerging adults that could be relevant for arboviral transmission. Methods We exposed Ae. albopictus larvae to lethal concentration of Bti and studied the fitness and gut microbiota of tolerant larvae and their adult counterparts. We further compared the transcript abundance of nine key immunity genes in the gut of Bti-tolerant larvae and their emerging adults versus those not exposed to Bti. Results Our results showed that Bti exposure has multifaceted impacts on Ae. albopictus mosquitoes during both larval and adult stages. The carry-over effect of Bti exposure on tolerant larvae manifested in reduced adult emergence rate, shorter lifespan, and decreased fecundity. Bti also alters the gut microbiota of both larvae and adults. We observed higher microbial diversity in Bti-tolerant larvae and changes in the richness of core microbiota. Bti infection and the altered microbiota triggered immune responses in the larval and adult guts. Conclusions The observed reduction in mosquito fitness and changes in the composition of the microbiota of adults emerging from tolerant larvae could negatively influence mosquito vectorial capacity. Understanding these impacts is crucial for evaluating the broader implications of Bti-based insecticides in mosquito control programs. Graphical Abstract

Abstract Background Understanding of mosquito spatiotemporal dynamics is central to characterize candidate field sites for the sterile insect technique (SIT) testing, and is critical to the effective implementation and evaluation of pilot sterile male release programs. Here, we present a detailed description of Aedes albopictus (Skuse) egg-laying activity over a 6-year period in urban areas identified as potential SIT testing sites on Reunion Island. Method Weekly entomological collections using ovitraps were carried out in residential and adjacent uninhabited habitats in two urban areas, Duparc and Bois Rouge, in the municipality of Sainte Marie, Reunion Island. Time-series data incorporating the frequency of positive ovitraps and the total number of eggs/ovitrap recorded each time at each locality during the study period from May 2013 to December 2018 were analyzed with multifaceted statistical approaches including descriptive statistics and spatiotemporal analyses incorporating the role of climatic factors on overall ovitrap productivity. Results During the ovitrap survey, the proportion of egg-positive ovitraps differed among study sites (χ 2 = 50.21, df = 2, P

Abstract Background Dengue fever is one of the most prevalent mosquito-borne diseases in Cambodia. Until now, no specific vaccine nor antiviral treatment exists the virus causing Dengue fever. Consequently, its prevention relies only on vector control strategies. However, efficient vector control in turn relies on a good knowledge of the biology of the vector species. Therefore, this study aims to provide the first review of the distribution, ecology, meteorological impacts, trophic behavior, vector competence, vector control and insecticide resistance of dengue vector species in Cambodia. Methods A systematic search of the Google Scholar and PubMed databases was conducted for relevant published articles. Of the 610 published articles originally identified, 70 articles were ultimately selected for inclusion in this review. We also included new data from unpublished research conducted in Cambodia between 2017 and 2023 related to dengue vector bionomics. Results Eleven Aedes (Stegomyia) mosquito species have been recorded in Cambodia, including a new species described in 2024. Four species are associated with dengue virus transmission, among which Aedes aegypti and Ae. albopictus are the main vectors and Ae. malayensis and Ae. scutellaris are considered to be potential vectors. Aedes aegypti and Ae. albopictus are present in all provinces of Cambodia. Aedes albopictus shows a preference for forest, rural and suburban areas, while Ae. aegypti is mostly found in urban and suburban areas. The distribution of these two species is also influenced by meteorological factors, seasonality and the availability of breeding habitats and blood meals. Both species are predominant during the rainy season, and their respective density is impacted by precipitation and temperature. Aedes aegypti is characterized as anthropophilic, while Ae. albopictus exhibits zooanthropophilic behavior, and both species have been observed to be predominantly diurnal. In addition, they were found to be highly resistant to the insecticides used in Cambodia for their control, such as temephos for larvae and deltamethrin and permethrin for adult mosquitoes. Conclusions This review provides extensive and important knowledge on dengue vectors in Cambodia. This knowledge is derived not only from published research articles but also from many recent studies in Cambodia on the bionomics of dengue vector species. The review provides valuable information for use by public health authorities on dengue virus transmission and to develop better vector control strategies in the country. Graphical Abstract

Abstract Background Vector-borne diseases cause morbidity and mortality globally. However, some areas are more impacted than others, especially with climate change. Controlling vectors remains the primary means to prevent these diseases, but new, more effective tools are needed. The World Health Organization (WHO) prioritized evaluating novel control methods, such as sterile insect technique (SIT) for control of Aedes-borne diseases. In response, a multiagency partnership between the U.S. Centers for Disease Control and Prevention (CDC), the Special Programme for Research and Training in Tropical Diseases (TDR), WHO, and the International Atomic Energy Agency (IAEA) supported the operational implementation and evaluation of SIT against Aedes aegypti and arboviral diseases in the Pacific through a consortium of regional partners (PAC-SIT Consortium). Main text A workshop was held from 2 to 6 May 2023, during which PAC-SIT country participants, researchers, and stakeholders in SIT, scientific advisory committee members, and organizational partners came together to review the principles and components of SIT, share experiences, visit field sites and the SIT facility, and officially launch the PAC-SIT project. Working in groups focused on entomology, epidemiology, and community engagement, participants addressed challenges, priorities, and needs for SIT implementation. Conclusions The PAC-SIT workshop brought together researchers and stakeholders engaged in evaluating SIT for arboviral diseases in the Pacific region and globally. This training workshop highlighted that many countries are actively engaged in building operational capacities and phased testing of SIT. The workshop identified a key need for robust larger-scale studies tied with epidemiological endpoints to provide evidence for the scalability and impact on mosquito-borne diseases.

Abstract Background Disease-vector mosquito monitoring is an essential prerequisite to optimize control interventions and evidence-based risk predictions. However, conventional entomological monitoring methods are labor- and time-consuming and do not allow high temporal/spatial resolution. In 2022, a novel system coupling an optical sensor with machine learning technologies (VECTRACK) proved effective in counting and identifying Aedes albopictus and Culex pipiens adult females and males. Here, we carried out the first extensive field evaluation of the VECTRACK system to assess: (i) whether the catching capacity of a commercial BG-Mosquitaire trap (BGM) for adult mosquito equipped with VECTRACK (BGM + VECT) was affected by the sensor; (ii) the accuracy of the VECTRACK algorithm in correctly classifying the target mosquito species genus and sex; (iii) Ae. albopictus capture rate of BGM with or without VECTRACK. Methods The same experimental design was implemented in four areas in northern (Bergamo and Padua districts), central (Rome) and southern (Procida Island, Naples) Italy. In each area, three types of traps—one BGM, one BGM + VECT and the combination of four sticky traps (STs)—were rotated each 48 h in three different sites. Each sampling scheme was replicated three times/area. Collected mosquitoes were counted and identified by both the VECTRACK algorithm and operator-mediated morphological examination. The performance of the VECTRACK system was assessed by generalized linear mixed and linear regression models. Aedes albopictus capture rates of BGMs were calculated based on the known capture rate of ST. Results A total of 3829 mosquitoes (90.2% Ae. albopictus) were captured in 18 collection-days/trap/site. BGM and BGM + VECT showed a similar performance in collecting target mosquitoes. Results show high correlation between visual and automatic identification methods (Spearman Ae. albopictus: females = 0.97; males = 0.89; P

Abstract Background Insecticide resistance poses a significant challenge in the implementation of vector-borne disease control strategies. We have assessed the resistance levels of Aedes albopictus to deltamethrin and pyriproxyfen (PPF) in Fujian Province (China) and investigated the correlation between these resistance levels and mutations in the voltage-gated sodium channel (VGSC). Methods The WHO bioassay protocol was used to evaluate the resistance coefficient of Ae. albopictus to deltamethrin and PPF, comparing a susceptible population from the Foshan (FS) area with wild populations from the Sanming (SM), Quanzhou (QZ), Zhangzhou (ZZ), Putian (PT) and Fuzhou (FZ) areas in Fujian Province. Genomic DNA was analyzed by PCR and sequencing to detect knockdown resistance (kdr) in the VGSC, specifically at the pyrethroid resistance alleles V1016V, I1532I and F1534F. Molecular docking was also performed to analyze the binding interactions of PPF and its metabolite 4'-OH-PPF to cytochrome P450 (CYP) 2C19, 2C9 and 3A4 and Ae. albopictus methoprene-tolerant receptors (AeMet), respectively. Results The analysis of resistance to deltamethrin and PPF among Ae. albopictus populations from the various regions revealed that except for the sensitive population in FS and the SM population, the remaining four regional populations demonstrated resistance levels ranging from 4.31- to 18.87-fold for deltamethrin and from 2.85– to 3.62-fold for PPF. Specifically, the FZ and PT populations exhibited high resistance to deltamethrin, whereas the ZZ and QZ populations approached moderate resistance levels. Also, the resistance of the FZ, PT and ZZ populations to PPF increased slowly but consistently with the increasing trend of deltamethrin resistance. Genomic analysis identified multiple non-synonymous mutations within the VGSC gene; the F1534S and F1534L mutations showed significant resistance to deltamethrin in Ae. albopictus. Molecular docking results revealed that PPF and its metabolite 4'-OH-PPF bind to the Ae. albopictus AeMet receptor and CYP2C19. Conclusions The wild Ae. albopictus populations of Fujian Province showed varying degrees of resistance to deltamethrin and PPF and a trend of cross-resistance to deltamethrin and PPF. Increased vigilance is needed for potential higher levels of cross-resistance, especially in the PT and FZ regions. Graphical Abstract

Abstract Climatic, ecological, and socioeconomic factors are facilitating the spread of mosquito-borne diseases, heightening the importance of vector surveillance and control. Citizen science is proving to be an effective tool to track mosquito populations, but methods are needed to detect and account for small scale sampling biases in citizen science surveillance. In this article we combine two types of traditional mosquito surveillance records with data from the Mosquito Alert citizen science system to explore the ways in which the socioeconomic characteristics of urban neighborhoods result in sampling biases in citizen scientists’ mosquito reports, while also shaping the spatial distribution of mosquito populations themselves. We use Barcelona, Spain, as an example, and focus on Aedes albopictus, an invasive vector species of concern worldwide. Our results suggest citizen scientists’ sampling effort is focused more in Barcelona’s lower and middle income census tracts than in its higher income ones, whereas Ae. albopictus populations are concentrated in the city’s upper-middle income tracts. High resolution estimates of the spatial distribution of Ae. albopictus risk can be improved by controlling for citizen scientists’ sampling effort, making it possible to provide better insights for efficiently targeting control efforts. Our methodology can be replicated in other cities faced with vector mosquitoes to improve public health responses to mosquito-borne diseases, which impose massive burdens on communities worldwide.

Abstract Background Aedes albopictus, commonly known as the Asian tiger mosquito, has become one of the most invasive mosquito species. Over the last 5 decades, it has been introduced and established in various tropical and temperate regions worldwide. First reported in Europe in 1979 in Albania and later in Italy in 1990, the species is now established in 13 European Union (EU)/European Economic Area (EEA) countries and 337 regions (2023). In Portugal, Ae. albopictus was first detected in the Algarve and Penafiel regions in 2017, followed by Alentejo in 2022 and Lisbon in 2023. This mosquito species poses a significant public health risk as a vector for numerous pathogenic viruses, including dengue, Zika, and chikungunya. Methods Aedes albopictus collected in Lisbon in 2023 were analyzed using cytochrome c oxidase I (COX) gene sequencing to understand their genetic relationships. Results Our data indicate that the Ae. albopictus mosquito populations detected in three locations in Lisbon in 2023 correspond to recent but distinct introduction events. Conclusions Although there has been no local transmission of Aedes-transmitted viruses in mainland Portugal to date, the spread of the mosquito and increased international travel increase the risk of Aedes-borne disease outbreaks. The ongoing spread of Ae. albopictus in the country and the confirmed multiple introductions in new locations raise awareness of the need to monitor mosquito vectors to control and prevent autochthonous Aedes-borne disease outbreaks. Graphical Abstract

Abstract Background C-type lectins (CTLs) are a large family of proteins with sugar-binding activity. CTLs contain an evolutionarily conserved C-type lectin domain (CTLD) that binds microbial carbohydrates in a calcium-dependent manner, thereby playing a key role in both microbial pathogenesis and innate immune responses. Aedes albopictus is an important vector for transmitting dengue virus (DENV) worldwide. Currently, the molecular characteristics and functions of CTLs in Ae. albopictus are largely unknown. Methods Transcripts encoding CTL proteins in the Ae. albopictus genome assembly were analyzed via sequence blast. Phylogenetic analysis and molecular characterization were performed to identify the functional domains of the CTLs. Quantitative analysis was performed to determine the gene expression features of CTLs during mosquito development and in different tissues of female adults after blood feeding. In addition, the functional role of CTLs in response to DENV infection was investigated in Ae. albopictus mosquito cells. Results We identified 39 transcripts encoding CTL proteins in the Ae. albopictus transcriptome. Aedes albopictus CTLs are classified into three groups based on the number of CTLDs and the domain architecture. These included 29 CTL-Ss (single-CTLDs), 1 immulectins (dual-CTLD) and 9 CTL-Xs (CTLDs with other domains). Phylogenetic analysis and structural modeling indicated that CTLs in Ae. albopictus are highly conserved with the homologous CTLs in Aedes aegypti. The expression profile assay revealed differential expression patterns of CTLs in both developmental stages and in adult female tissues. Knockdown and overexpression of three CTLs (CTL-S12, S17 and S19) confirmed that they can promote dengue virus infection in Ae. albopictus cells. Conclusions The CTL genes in Ae. albopictus mosquito and other mosquito species are evolutionarily conserved and exhibit different developmental and tissue expression features. The functional assay indicated that three CTLs in Ae. albopictus mosquitoes are involved in promoting dengue virus infection. Our study revealed that CTLs play important roles in both the physiological processes and viral infection in mosquito vectors. Graphical Abstract

Abstract The mosquito microbiome significantly influences vector competence, including in Aedes albopictus, a globally invasive vector. Describing the microbiome and Wolbachia strains of Ae. albopictus from different regions can guide area-specific control strategies. Mosquito samples from Spain and São Tomé were analyzed using 16S rRNA gene sequencing and metagenomic sequencing. Wolbachia infection patterns were observed by sex and population. Female mosquitoes were blood-fed, a factor considered in analyzing their microbiota. Results revealed a dominance of dual Wolbachia infections, strains A and B, in the microbiome of both populations of Ae. albopictus, especially among females. Both populations shared a core microbiome, although 5 and 9 other genera were only present in Spain and São Tomé populations, respectively. Genera like Pelomonas and Nevskia were identified for the first time in Aedes mosquitoes. This study is the first to describe the Ae. albopictus bacteriome in Spain and São Tomé, offering insights for the development of targeted mosquito control strategies. Understanding the specific microbiome composition can help in designing more effective interventions, such as microbiome manipulation and Wolbachia-based approaches, to reduce vector competence and transmission potential of these mosquitoes.

The Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae), is a global vector of dengue, chikungunya and zika viruses. With extreme adaptability of survival as diapause eggs, this mosquito has invaded and established in temperate climatic zones. The diapause eggs are specially programmed to overcome the harsh winter conditions in temperate habitats. In the laboratory, diapausing females are reared from early larval instars under short‐day conditions (21°C and 16D:8 L photoperiods). Aedes albopictus is normally fed on Guinea pigs for the rearing of diapause mosquitoes which requires ethical approval from the animal use committee and costly arrangements. Therefore, the present study was conducted to find whether bovine serum albumin protein (10%) with sucrose (5%) solution (SAP‐10) offered through a membrane‐free feeding system would result in an alternative diet for the production of diapause eggs in comparison to blood‐feeding. This feeding system shows a considerable rate of engorgement of diapausing females under short‐day conditions and produced 30.8 diapause eggs/female in comparison to blood‐feeding on a guinea pig (40.9 eggs/female). The diapause rate of viable eggs for the SAP‐10 diet (95.28%) was similar to the blood‐feeding (96.32%). The findings suggest that the present diet feeding system is a promising tool for the rearing of diapause Ae. albopictus mosquitoes under short‐day conditions. Further studies are suggested to evaluate the physiological and developmental aspects of mosquitoes reared on the diet. [ABSTRACT FROM AUTHOR]

Mosquitoes occupy a wide range of habitats where they experience various environmental conditions. The ability of some species, such as the tiger mosquito, Aedes albopictus, to adapt to local conditions certainly contributes to their invasive success. Among traits that remain to be examined, mosquitoes' ability to time their activity with that of the local host population has been suggested to be of significant epidemiological importance. However, whether different populations display heritable differences in their chronotype has not been examined. Here, we compared laboratory strains originating from eight populations from three continents, monitored their spontaneous locomotor activity patterns and analysed their sleep‐like states. Overall, all strains showed conserved diurnal activity concentrated in the hours preceding the crepuscule. Similarly, they all showed increased sleep levels during the morning and night hours. However, we observed strain‐specific differences in the activity levels at each phase of the day. We also observed differences in the fraction of time that each strain spends in a sleep‐like state, explained by variations in the sleep architecture across strains. Human population density and the latitude of the site of the geographic origin of the tested strain showed significant effects on sleep and activity patterns. Altogether, these results suggest that Ae. albopictus mosquitoes adapt to local environmental conditions via heritable adaptations of their chronotype. [ABSTRACT FROM AUTHOR]

Globalisation, climate change and international trade are the factors contributing to the spread of Aedes albopictus (Diptera: Culicidae) and Ae. aegypti into new areas. In newly invaded habitats, these non‐native species can serve as arbovirus disease vectors or increase the risk of disease spill over. These mosquitoes continue to emerge in new areas where they have or will have overlapping ranges with other resident mosquito species. The study investigates how invasive Aedes mosquitoes compete with the native Culex pipiens in Türkiye, which might affect the overall mosquito population dynamics and disease transmission risks. Both Aedes species exhibited contrasting responses to interspecific competition with Cx. pipiens. While Ae. albopictus suffers reduced emergence primarily in larger containers with abundant food, Ae. aegypti surprisingly thrives in mixed cultures under all food conditions. Adult Cx. pipiens emergence drops by half against Ae. albopictus and under specific conditions with Ae. aegypti. Competition influences mosquito size differently across species and life stages. Culex pipiens females grow larger when competing with Ae. aegypti, potentially indicating resource advantage or compensatory strategies. However, Ae. albopictus size shows more nuanced responses, suggesting complex interactions at play. Understanding how invasive and native mosquitoes interact with each other can provide insights into how they adapt and coexist in shared habitats. This knowledge can inform effective control strategies. The study highlights the differential responses of invasive Aedes species and the potential for managing populations based on their competitive interactions with the native Cx. pipiens. It can contribute to improved monitoring and prediction systems for the spread of invasive mosquitoes and the associated disease risks. [ABSTRACT FROM AUTHOR]

Dengue fever poses a global public health threat, with 2.5 billion people at risk of infection each year. Because the Aedes albopictus is the primary vector of dengue, it is closely monitored and handled. The efficiency of Dengue eradication is strongly dependent on understanding a female mosquito's physiological age. This study addresses key entomological issues about the impact of previtellogenic nutrition on egg production mechanisms. Ovarian development included two distinct periods: previtellogenesis and vitellogenesis. Sugar intake during previtellogenesis influences the size of the blood meal. The major parameter influencing the vitellogenesis process is the presence of a hematophagous feeding event following sugar concentration. Upon subjecting female mosquitoes to sucrose, the ovarian follicles entered the third phase of previtellogenesis. Once females feed on blood following sucrose, ovarian development enters the vitellogenesis, and the oocyte cytoplasm reveals that the yolk granules are organized in one or two rows like a crown, increasing oocyte size. Females fed 15% sucrose before a blood meal, have the largest vitellogenic growth, and follicular size, which is seven times greater than those fed water only. Fecundity increased by 78.7% by adding 7% sucrose to the diet. Mitochondria within oocytes increase, most likely due to their transportation from the nurse cells, where the yolk is synthesized. This study describes in detail the histological alterations detected in the ovaries during the previtellogenesis as well as those associated with yolk formation, suggesting that yolk protein deposition in the oocyte is associated with blood meal, independent of sucrose feeding. Research Highlights: Adult nutrition during previtellogenesis significantly impacts various biological parameters and the physiological age of adults of Aedes albopictus.Female mosquitoes experienced significant growth in vitellogenic development, vectorial capacity, and follicular size after consuming a diet with 15% sucrose before a blood meal. [ABSTRACT FROM AUTHOR]

Valorization of fruit wastes through fermentation yields a multipurpose liquid called jiaosu. This study was conducted to compare the biochemical content changes (pH, total proteins, total carbohydrates, total phenolics, total alcohols, and organic acids) before and after fermentation for three months, as well as to evaluate the antibacterial, antifungal, and mosquito larvicidal activities of three combinations of jiaosu samples, orange-papaya-watermelon (OPW), grapefruit-mango-pineapple (GMP), and durian-jackfruit-passion fruit (DJP). After fermentation, the jiaosu samples were acidic (pH 3.05–3.40). Only GMP and DJP showed increased total protein content (p < 0.05). All samples utilized carbohydrates extensively during fermentation and displayed significant increases (p < 0.05) in total phenolic contents. Alcohols were detected in all samples (2.15% ± 0.05%–8.34% ± 0.06%) after fermentation. All organic acids (oxalic, tartaric, malic, lactic, acetic, citric, and succinic acids) were significantly increased (p < 0.05) in all samples except for the tartaric and succinic acids in OPW which decreased after fermentation. All samples exhibited minimum inhibitory concentrations of 25–50% v/v against five species of human pathogenic bacteria and minimum fungicidal concentrations of 12.5–50% v/v against the fungus Cryptococcus neoformans. All samples showed strong larvicidal activity against the third instar larvae of Aedes spp. mosquitoes. The larvae of Aedes aegypti were more susceptible to the jiaosu samples than Aedes albopictus with the respective median lethal concentrations (LC50) of 2.14–5.16% v/v and 6.52–14.55% v/v, after 24 h post-treatment. The findings from this study recorded the biochemical changes in different fruit peel combinations of jiaosu during fermentation and the potential use of jiaosu as cleaning agent and biopesticide. [ABSTRACT FROM AUTHOR]

BACKGROUND: The incompatible insect technique (IIT) has been used for Aedes mosquito population suppression to curb the transmission of dengue. However, its wide application is limited owing to the low output of male mosquitoes and the risk of population replacement from the release of fertile Wolbachia‐infected females. This study aims to improve IIT efficiency for broader adoption. RESULTS: We assessed the impact of 10% pyriproxyfen (PPF) sticky powder exposure on Wolbachia (from Culex molestus)‐transinfected Aedes albopictus Guangzhou line (GUA line) (GC) mosquitoes. We found that the exposure caused chronic toxicity in adult mosquitoes without affecting the cytoplasmic incompatibility (CI)‐inducing capability of males. The PPF‐contaminated GC females exhibited significant sterilization and the ability to disseminate lethal doses of PPF to breeding sites. Subsequently, we conducted a field trial combining PPF with IIT aiming to suppress the Ae. albopictus population. This combined approach, termed boosted IIT (BIIT), showed a notable enhancement in population suppression efficiency. The improved efficacy of BIIT was attributed to the dispersion of PPF particles in the field via the released PPF‐contaminated male mosquitoes. During the BIIT field trial, no Wolbachia wPip‐positive Ae. albopictus larvae were detected, indicating the effective elimination of the risk of Wolbachia‐induced population replacement. Additionally, the field trial of BIIT against Ae. albopictus resulted in the suppression of the nontarget mosquito species Culex quinquefasciatus. CONCLUSION: Our results highlight the remarkable efficiency and feasibility of combining IIT with PPF in suppressing mosquito populations, facilitating the widespread implementation of IIT‐based management of mosquito‐borne diseases. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Abstract Background Aedes albopictus is a major arbovirus vector with small stagnant water containers being its oviposition sites. Mosquitoes search for these sites based on their olfactory cues (odor and moisture emanating from the water at the oviposition site), visual cues (size and color of the site), and gustatory cues (ion and nutrient concentration in that water). The gustatory mechanism through which mosquitoes search for oviposition sites remains unknown. Methods To investigate the role of taste receptors in Ae. albopictus oviposition site selection, we developed a laboratory model. This model assessed mosquito behavior in locating and detecting oviposition sites, using a location index to quantify site preference and detection time to measure response to water presence. We compared oviposition site-searching efficiency between mosquitoes with blocked and unblocked appendages, targeting the taste organs. Transcriptome sequencing was conducted to identify differentially expressed genes between water-exposed and unexposed mosquitoes. CRISPR/Cas9 technology was then employed to generate a mutant strain with a targeted gene knockout. Results There was no significant difference between the blocked and unblocked groups in the location index. In contrast, the detection time of the unblocked group differed significantly from all other groups, including those with blocked foreleg tarsus, midleg tarsus, hindleg tarsus, all tibia, and all tarsus. Transcriptome sequencing analyses of water-exposed and unexposed mosquitoes revealed that the taste-related gene gustatory receptor 11(gr11) was differentially expressed. This gene was knocked out with CRISPR/Cas9 technology to generate a pure mutant strain with 2- and 4-bp deletions, which exhibited a significantly longer detection time than the wild-type strain. Conclusions This study reveals the role of Ae. albopictus gr11 in water detection at oviposition sites, thereby providing a theoretical basis and scientific guidelines for managing the breeding sites of these mosquitoes. Graphical Abstract

Abstract Background Aedes albopictus is an important vector for pathogens such as dengue, Zika, and chikungunya viruses. While insecticides is the mainstay for mosquito control, their widespread and excessive use has led to the increased resistance in Ae. albopictus globally. Gut symbiotic bacteria are believed to play a potential role in insect physiology, potentially linking to mosquitoes’ metabolic resistance against insecticides. Methods We investigated the role of symbiotic bacteria in the development of resistance in Ae. albopictus by comparing gut symbiotic bacteria between deltamethrin-sensitive and deltamethrin-resistant populations. Adults were reared from field-collected larvae. Sensitive and resistant mosquitoes were screened using 0.03% and 0.09% deltamethrin, respectively, on the basis of the World Health Organization (WHO) tube bioassay. Sensitive and resistant field-collected larvae were screened using 5 × LC50 (lethal concentration at 50% mortality) and 20 × LC50 concentration of deltamethrin, respectively. Laboratory strain deltamethrin-sensitive adults and larvae were used as controls. The DNA of gut samples from these mosquitoes were extracted using the magnetic bead method. Bacterial 16S rDNA was sequenced using BGISEQ method. We isolated and cultured gut microorganisms from adult and larvae mosquitoes using four different media: Luria Bertani (LB), brain heart infusion (BHI), nutrient agar (NA), and salmonella shigella (SS). Results Sequencing revealed significantly higher gut microbial diversity in field-resistant larvae compared with field-sensitive and laboratory-sensitive larvae (P

Abstract Background The Aedes albopictus mosquito is of medical concern due to its ability to transmit viral diseases, such as dengue and chikungunya. Aedes albopictus originated in Asia and is now present on all continents, with the exception of Antarctica. In Mozambique, Ae. albopictus was first reported in 2015 within the capital city of Maputo, and by 2019, it had become established in the surrounding area. It was suspected that the mosquito population originated in Madagascar or islands of the Western Indian Ocean (IWIO). The aim of this study was to determine its origin. Given the risk of spreading insecticide resistance, we also examined relevant mutations in the voltage-sensitive sodium channel (VSSC). Methods Eggs of Ae. albopictus were collected in Matola-Rio, a municipality adjacent to Maputo, and reared to adults in the laboratory. Cytochrome c oxidase subunit I (COI) sequences and microsatellite loci were analyzed to estimate origins. The presence of knockdown resistance (kdr) mutations within domain II and III of the VSSC were examined using Sanger sequencing. Results The COI network analysis denied the hypothesis that the Ae. albopictus population originated in Madagascar or IWIO; rather both the COI network and microsatellites analyses showed that the population was genetically similar to those in continental Southeast Asia and Hangzhou, China. Sanger sequencing determined the presence of the F1534C knockdown mutation, which is widely distributed among Asian populations, with a high allele frequency (46%). Conclusions These results do not support the hypothesis that the Mozambique Ae. albopictus population originated in Madagascar or IWIO. Instead, they suggest that the origin is continental Southeast Asia or a coastal town in China. Graphical Abstract

Abstract Background Past findings demonstrate that arthropods can egest midgut microbiota into the host skin leading to dual colonization of the vertebrate host with pathogens and saliva microbiome. A knowledge gap exists on how the saliva microbiome interacts with the pathogen in the saliva. To fill this gap, we need to first define the microbial composition of mosquito saliva. Methods The current study aimed at analyzing and comparing the microbial profile of Aedes albopictus saliva and midgut as well as assessing the impact of Zika virus (ZIKV) infection on the midgut and saliva microbial composition. Colony-reared Ae. albopictus strains were either exposed to ZIKV infectious or noninfectious bloodmeal. At 14 ays postinfection, the 16S V3–V4 hypervariable rRNA region was amplified from midgut and saliva samples and sequenced on an Illumina MiSeq platform. The relative abundance and diversity of midgut and saliva microbial taxa were assessed. Results We observed a richer microbial community in the saliva compared with the midgut, yet some of the microbial taxa were common in the midgut and saliva. ZIKV infection did not impact the microbial diversity of midgut or saliva. Further, we identified Elizabethkingia spp. in the Ae. albopictus saliva. Conclusions This study provides insights into the microbial community of the Ae. albopictus saliva as well as the influence of ZIKV infection on the microbial composition of its midgut and saliva. The identification of Elizabethkingia spp., an emerging pathogen of global health significance, in Ae. albopictus saliva is of medical importance. Future studies to assess the interactions between Ae. albopictus saliva microbiome and ZIKV could lead to novel strategies for developing transmission barrier tools. Graphical Abstract

Abstract Background RNA interference (RNAi) is a target-specific gene silencing method that can be used to determine gene functions and investigate host–pathogen interactions, as well as facilitating the development of ecofriendly pesticides. Commercially available transfection reagents (TRs) can improve the efficacy of RNAi. However, we currently lack a product and protocol for the transfection of insect cell lines with long double-stranded RNA (dsRNA). Methods We used agarose gel electrophoresis to determine the capacity of eight TRs to form complexes with long dsRNA. A CellTiter-Glo assay was then used to assess the cytotoxicity of the resulting lipoplexes. We also measured the cellular uptake of dsRNA by fluorescence microscopy using the fluorophore Cy3 as a label. Finally, we analyzed the TRs based on their transfection efficacy and compared the RNAi responses of Aedes albopictus C6/36 and U4.4 cells by knocking down an mCherry reporter Semliki Forest virus in both cell lines. Results The TRs from Biontex (K4, Metafectene Pro, and Metafectene SI+) showed the best complexing capacity and the lowest dsRNA:TR ratio needed for complete complex formation. Only HiPerFect was unable to complex the dsRNA completely, even at a ratio of 1:9. Most of the complexes containing mCherry-dsRNA were nontoxic at 2 ng/µL, but Lipofectamine 2000 was toxic at 1 ng/µL in U4.4 cells and at 2 ng/µL in C6/36 cells. The transfection of U4.4 cells with mCherry-dsRNA/TR complexes achieved significant knockdown of the virus reporter. Comparison of the RNAi response in C6/36 and U4.4 cells suggested that C6/36 cells lack the antiviral RNAi response because there was no significant knockdown of the virus reporter in any of the treatments. Conclusions C6/36 cells have an impaired RNAi response as previously reported. This investigation provides valuable information for future RNAi experiments by showing how to mitigate the adverse effects attributed to TRs. This will facilitate the judicious selection of TRs and transfection conditions conducive to RNAi research in mosquitoes. Graphical Abstract

Background: Aedes albopictus is a major arbovirus vector with small stagnant water containers being its oviposition sites. Mosquitoes search for these sites based on their olfactory cues (odor and moisture emanating from the water at the oviposition site), visual cues (size and color of the site), and gustatory cues (ion and nutrient concentration in that water). The gustatory mechanism through which mosquitoes search for oviposition sites remains unknown. Methods: To investigate the role of taste receptors in Ae. albopictus oviposition site selection, we developed a laboratory model. This model assessed mosquito behavior in locating and detecting oviposition sites, using a location index to quantify site preference and detection time to measure response to water presence. We compared oviposition site-searching efficiency between mosquitoes with blocked and unblocked appendages, targeting the taste organs. Transcriptome sequencing was conducted to identify differentially expressed genes between water-exposed and unexposed mosquitoes. CRISPR/Cas9 technology was then employed to generate a mutant strain with a targeted gene knockout. Results: There was no significant difference between the blocked and unblocked groups in the location index. In contrast, the detection time of the unblocked group differed significantly from all other groups, including those with blocked foreleg tarsus, midleg tarsus, hindleg tarsus, all tibia, and all tarsus. Transcriptome sequencing analyses of water-exposed and unexposed mosquitoes revealed that the taste-related gene gustatory receptor 11(gr11) was differentially expressed. This gene was knocked out with CRISPR/Cas9 technology to generate a pure mutant strain with 2- and 4-bp deletions, which exhibited a significantly longer detection time than the wild-type strain. Conclusions: This study reveals the role of Ae. albopictus gr11 in water detection at oviposition sites, thereby providing a theoretical basis and scientific guidelines for managing the breeding sites of these mosquitoes. [ABSTRACT FROM AUTHOR]

The Dengue virus (DENV), primarily spread by Aedes aegypti and also by Aedes albopictus in some regions, poses significant global health risks. Alternative techniques are urgently needed because the current control mechanisms are insufficient to reduce the transmission of DENV. Introducing Wolbachia pipientis into Ae. aegypti inhibits DENV transmission, however, the underlying mechanisms are still poorly understood. Innate immune effector upregulation, the regulation of autophagy, and intracellular competition between Wolbachia and DENV for lipids are among the theories for the mechanism of inhibition. Furthermore, mainly three immune pathways Toll, IMD, and JAK/STAT are involved in the host for the suppression of the virus. These pathways are activated by Wolbachia and DENV in the host and are responsible for the upregulation and downregulation of many genes in mosquitoes, which ultimately reduces the titer of the DENV in the host. The functioning of these immune pathways depends upon the Wolbachia, host, and virus interaction. Here, we summarize the current understanding of DENV recognition by the Ae. aegypti's immune system, aiming to create a comprehensive picture of our knowledge. Additionally, we investigated how Wolbachia regulates the activation of multiple genes associated with immune priming for the reduction of DENV. [ABSTRACT FROM AUTHOR]

Background: Aedes albopictus is catalogued as one of the 100 most dangerous species worldwide. Native to Asia, the species has drastically increased its distribution range, reaching all continents except Antarctica. The presence of Ae. albopictus in Spain was first reported in 2004 in Cataluña (NE Spain), and it is spreading in the country. Methods: We conducted an extensive mosquito monitoring study in the natural protected area of the Doñana National Park (SW Spain) in 2023. After identifying the presence of Ae. albopictus, a mosquito control strategy was developed and implemented to eradicate the species in the area. Results: Overall, 12,652 mosquito females of 14 different species were captured at nine sites within the park. For the first time, the presence of Ae. albopictus was recorded in the area, despite intensive trapping performed at some localities since 2003. The presence of this invasive species in the park is most likely linked to human activities, potentially facilitated by daily car trips of personnel. Although larvae of Culex, Anopheles, and Culiseta mosquitoes were identified in these containers, the presence of Ae. albopictus larvae was not recorded in those locations. In spite of that, the biological larvicide Bacillus thuringiensis israelensis (Bti) was applied to artificial containers potentially used by Ae. albopictus as breeding sites. Conclusions: This work evidences the high capacity of Ae. albopictus to reach highly conserved natural areas far from urban foci. We discuss the implications of the presence of Ae. albopictus in this endangered ecosystem and the potential control measures necessary to prevent its reintroduction. [ABSTRACT FROM AUTHOR]

Aedes albopictus is an important vector of arboviruses and prefers small containers of stagnant water as oviposition sites. One of the mechanisms mosquitoes use to search for suitable oviposition sites is relying on odor cues from prospective sites and their surroundings. The genetic and molecular bases of this behavior are not known for Ae. albopictus. Oviposition site‐searching behavior can be separated into 2 stages: container location and water detection. We applied a glue compound to the antennae and the maxillary palps of adult females to mask their ability to detect molecules that may guide them to preferred oviposition sites. Treatment of the antennae significantly reduces the location index (P < 0.001), indicating a decreased ability to find oviposition sites, whereas no significant difference was observed in mosquitoes with maxillary palps treated with the same glue compound (P > 0.05). The detection time, measured as the duration from contact with the water surface to the deposition of the first egg, was extended in mosquitoes with treated antennae or maxillary palps, supporting the conclusion that olfaction is involved in the detection of oviposition site. Transcriptomic analysis identified differentially expressed olfactory‐related genes, including obp67, obp56d‐like, obp19d‐like and obp67‐like. RNA interference (RNAi)‐mediated knockdown of obp67 and obp56d‐like significantly affected the location index and detection time, respectively. Cas9/guide RNA‐mediated knockout of obp56d‐like resulted in a prolonged detection time, compared with the wild type (P < 0.05). These findings help to elucidate aspects of the olfactory mechanisms involved in Ae. albopictus oviposition site selection, and provide a basis for the development of mosquito surveillance and control strategies. [ABSTRACT FROM AUTHOR]

Avian malaria is expanding upslope with warmer temperatures and driving multiple species of Hawaiian birds towards extinction. Methods to reduce malaria transmission are urgently needed to prevent further declines. Releasing Wolbachia-infected incompatible male mosquitoes could suppress mosquito populations and releasing Wolbachia-infected female mosquitoes (or both sexes) could reduce pathogen transmission if the Wolbachia strain reduced vector competence. We cleared Culex quinquefasciatus of their natural Wolbachia pipientis wPip infection and transinfected them with Wolbachia wAlbB isolated from Aedes albopictus. We show that wAlbB infection was transmitted transovarially, and demonstrate cytoplasmic incompatibility with wild-type mosquitoes infected with wPip from Oahu and Maui, Hawaii. We measured vector competence for avian malaria, Plasmodium relictum, lineage GRW4, of seven mosquito lines (two with wAlbB; three with natural wPip infection, and two cleared of Wolbachia infection) by allowing them to feed on canaries infected with recently collected field isolates of Hawaiian P. relictum. We tested 73 groups (Ntotal = 1176) of mosquitoes for P. relictum infection in abdomens and thoraxes 6–14 days after feeding on a range of parasitemias from 0.028% to 2.49%, as well as a smaller subset of salivary glands. We found no measurable effect of Wolbachia on any endpoint, but strong effects of parasitemia, days post feeding, and mosquito strain on both abdomen and thorax infection prevalence. These results suggest that releasing male wAlbB-infected C. quinquefasciatus mosquitoes could suppress wPip-infected mosquito populations, but would have little positive or negative impact on mosquito vector competence for P. relictum if wAlbB became established in local mosquito populations. More broadly, the lack of Wolbachia effects on vector competence we observed highlights the variable impacts of both native and transinfected Wolbachia infections in mosquitoes. Author summary: Avian malaria is expanding upslope in Hawaii with warmer temperatures and driving multiple species of birds towards extinction. Methods to reduce malaria transmission are urgently needed to prevent further declines. Releasing male mosquitoes infected with a type of bacteria (Wolbachia) could suppress mosquito populations by reducing offspring viability and releasing Wolbachia-infected female mosquitoes (or both sexes) could reduce pathogen transmission if the Wolbachia strain reduced vector competence. We cleared Culex quinquefasciatus of their natural Wolbachia pipientis wPip infection and transinfected them with Wolbachia wAlbB isolated from Aedes albopictus. We show that wAlbB infection was transmitted to offspring, and mating wAlbB males with wild-type mosquitoes produced mostly inviable offspring. We measured susceptibility to avian malaria infection of mosquitoes with native or transinfected Wolbachia (wPip or wAlbB). We found no measurable effect of Wolbachia on susceptibility. These results suggest that releasing male wAlbB-infected C. quinquefasciatus mosquitoes could suppress Hawaiian mosquito populations, but would have little positive or negative impact on mosquito vector competence for avian malaria. More broadly, the lack of Wolbachia effects on susceptibility to avian malaria we observed highlights the variable impacts of both native and transinfected Wolbachia infections in mosquitoes. [ABSTRACT FROM AUTHOR]

Dengue fever is influenced by physical environmental factors that control the population dynamics of Aedes mosquito vectors. Studying the spatial distribution patterns of dengue patients using geographic information system tools, combined with surveys of Aedes mosquito larvae index through public health methods, can help understand the phenomenon and the spatial relationships with land use patterns. This study aims to investigate the spatial and temporal distribution of dengue fever in Phuket Province and examine the spatial relationship of the Aedes mosquito larvae index. A broad overview of the entire province using dengue patient data from 2007 to 2017 revealed a significant outbreak in 2013, with the majority occurring during the rainy season, and only a few cases in other seasons. Furthermore, village-level patient data were linked with Geographic Information Systems (GIS) data to map the epidemic locations, showing that the highest number of cases were consistently found in Mueang Phuket District every year. However, when considering the incidence rate per 100,000 people, a different pattern emerged, indicating the highest outbreak concentration in two specific villages within Thalang District. Field data collection of the Aedes mosquito larvae index in six communities showed a significant spatial relationship with land use characteristics in the surrounding area when considering the Aedes species. In the end of the rainy season, Aedes aegypti was predominantly found in urban areas, while both Aedes aegypti and Aedes albopictus were found in semi-rural and forested areas. Additionally, in both the summer and rainy seasons, both species could be found in the same containers. This indicates that besides the natural habitat in natural water containers, Aedes albopictus also lay eggs in the containers around human dwellings. Aedes albopictus is not only a vector for dengue fever, but also for Chikungunya and Zika viruses, which increases threat to humans. Therefore, communities near agricultural and forested areas should exercise extra caution. Public health authorities are supposed to plan the prevention of dengue fever and other mosquito-borne diseases to ensure a balance among health, society, economy and the environment. [ABSTRACT FROM AUTHOR]

Introduction: Dengue, also known as "break bone fever," is a viral infection transmitted by Aedes aegypti followed by Aedes albopictus. It is more prevalent in tropical and subtropical climates. While many individuals infected with dengue may not experience any symptoms, those who do may commonly exhibit high fever, headache, body aches, nausea, and rash. In severe cases, dengue can be fatal, with some individuals developing dengue haemorrhagic fever characterized by bleeding, low blood platelet levels, and blood plasma leakage, or dengue shock syndrome, which involves dangerously low blood pressure. Aim: To detect Dengue IgM with IgM capture ELISA in NS1 positive samples of patients attending a tertiary care hospital. Material and Methods: This study was conducted as a prospective cohort study, conducting within the study period June 2022 to December 2022 involving patients admitted to GBCM and Subharti hospital, Dehradun. A Comparative study to detect Dengue IgM with IgM capture ELISA in NS1 positive samples of patients attending a tertiary care hospital among 498 patients. Results: Among 258 female patients, 24 were NS1-positive, 36 were IgM-positive, and 46 were IgG-positive and in male patients (240), 59 were NS1 positive, 40 were IgM positive, and 39 were IgG positive. In July 2022, a higher correlation coefficient of 0.422029 (p-value: 0.000570) was observed, indicating a stronger association between NS1 antigen and IgM seropositivity. Thrombocytopenia with most cases showing platelet counts ranging from 50,000 to 100,000 platelets/cu mm. Conclusion: This study enhances our understanding of the correlation between IgM seropositivity and NS1 antigen positivity in dengue cases within rural populations. The findings have significant implications for early detection, diagnosis, and management of dengue infection, emphasizing the value of IgM as a diagnostic marker. [ABSTRACT FROM AUTHOR]

Due to several epizootic events between 2020 and 2021 in the south of Brazil near the border with Argentina, we performed mosquito surveys in areas of epidemiological risk in northeast Argentina to evaluate abundance and distributions of mosquito vectors from the yellow fever virus (YFV) (Diptera: Culicidae). For the most abundant species, the number of individuals captured per collector was evaluated based on the capturing time range. With a total sampling effort of 191 collector-hours, we captured 676 mosquitoes belonging to 6 genera and 16 species. The most abundant species were Aedes (Ochlerotatus) scapularis (Rondani) (33.58%), Sabethes (Sabethes) albiprivus Theobald (20.27%), Aedes (Stegomyia) albopictus (Skuse) (17.75%) and Haemagogus (Conopostegus) leucocelaenus (Dyar and Shannon) (15.86%). Sabethes albiprivus and Ae. albopictus showed activity peaks at noon and morning, respectively, while other species showed no important time differences between 10:00AM and 15:00PM. Our results show that the most abundant mosquito species in those environments with epidemiological risk in northern Corrientes and southern Misiones are categorized as important in the transmission of the YFV. Moreover, we report an expansion of Ae. albopictus distribution and the first record of Aedes (Ochlerotatus) patersoni Shannon and Del Ponte in Corrientes and Misiones provinces. [ABSTRACT FROM AUTHOR]

Aedes albopictus (Skuse, 1895), the Asian tiger mosquito extended globally in just a few decades from Asia showing great adaptability despite temperature-dependent development. The present study revealed the effects of temperature (20 ℃, 26 ℃, 30 ℃, and 35 ℃) on various developmental parameters of Ae. albopictus strains belonging to the desert (Jodhpur, Rajasthan) and the coastal (Kolkata, West Bengal) regions of India. The desert strain developed faster from eggs-adult emergence (7.5 days at 35 ℃ and 14.0 days at 20 ℃) than the coastal strain (7.8 days at 35 ℃ and 16.8 days at 20 ℃). The survival was highest and lowest at 26 °C and 35 ℃, respectively, irrespective of strains and stages. The larval survival trends of both strains were similar to pupae across the temperature range. The wing length of the desert strain was shorter in comparison to the coastal strain. Wing length was found inversely proportional to the temperature being longest at 20 ℃ and the shortest at 35 ℃ for both strains. Male and female wing lengths were larger (25% and 22.7% in the Jodhpur strain and 24.6% and 23.6% in the Kolkata strain) at 20 ℃ compared to 35 ℃, respectively. Significant differences were observed between the male-female sex ratio in the coastal strain. The outcomes of the study suggest consideration of temperature impact on immature developmental attributes that might help in the refining of control measures and a better understanding of ecological adaptations in contrast to ecological conditions. [ABSTRACT FROM AUTHOR]

Aedes albopictus was first detected in the province of Valencia, Eastern Spain, in 2013. Since then, this invasive mosquito species has become a major pest in many municipalities due to its annoyance, but also to its importance as a public health concern as a potential vector of several arboviruses. Within the framework of the NESCOTIGER research project, several prevention and control activities were carried out during spring 2022 in the residential area of Torrent, a municipality recently invaded by the Asian tiger mosquito. An awareness campaign was conducted in the study area focused to both primary school students and residents. For children, talks in primary schools focusing on the basic aspects of the biology, prevention, control, and disease transmission of Ae. albopictus were conducted. For adults, a multi-pronged education campaign to mobilize the community in response to this mosquito species was devised, involving a series of workshops and local gatherings to raise awareness about Ae. albopictus. Additionally, a knowledge, attitude and practices (KAP) study was conducted on both children (n = 544; 75.7%) and adults (n = 175; 24.3%). Both adults and children showed low levels of knowledge concerning Ae. albopictus biology, control strategies, and breeding sites identification. Nevertheless, there was great interest in learning and participating in novel strategies against this Aedes invasive mosquito. Future awareness campaigns in the area should consider the information gathered here for the development of community-based strategies. This study is the first to collect information on the KAP of local community members since the detection of Ae. albopictus in Spain, and it is the first to compare KAP surveys between adults and children concerning this invasive mosquito. [ABSTRACT FROM AUTHOR]

The common house mosquito (Culex pipiens) is a native vector for West Nile virus (WNV). Invasive species like the tiger mosquito (Aedes albopictus) and Asian bush mosquito (Aedes japonicus) are rapidly spreading through Europe, posing a major threat as vectors for dengue, chikungunya (CHIKV), and Japanese encephalitis virus (JEV). These mosquitoes share a similar ecological niche as larvae, but the carry-over effects of aquatic larval interactions to the terrestrial adult stage remain largely unknown and their medical relevance requires further investigation. This study examines the context dependency of larval interactions among Aedes albopictus, Aedes japonicus, and Culex pipiens. The survival, development time, growth, and energetic storage were measured in different European populations within density-response (intraspecific) experiments and replacement (interspecific) experiments at 20 °C and 26 °C. Overall, Ae. japonicus was the weakest competitor, while competition between Ae. albopictus and Cx. pipiens varied with temperature. Adults emerging from this larval competition were infected as follows: Culex pipiens with WNV, Ae. albopictus with CHIKV, and Ae. japonicus with JEV. While no JEV infection was observed, mosquitoes experiencing interspecific interactions during their larval stages exhibited higher infection rates and viral RNA titers for CHIKV and WNV. This increased susceptibility to viral infection after larval competition suggests a higher risk of arbovirus transmission in co-occurring populations. [ABSTRACT FROM AUTHOR]

Simple Summary: Mosquito surveys conducted in the Democratic Republic of Sao Tome and Principe during 2000 to 2016 as a part of anti-malaria programs found the presence of four species of mosquitoes in the nation including Culex (Culex) poicilipes, Mansonia (Coquillettidia) annetti, Uranotaenia (Uranotaenia) alboabdominalis, and Uranotaenia (Uranotaenia) fraseri for the first time. Aedes albopictus (Skuse, 1894) was identified in 2015, and the follow-up survey confirmed that Aedes albopictus has become widespread across the nation. The larvae were predominant in artificial water-holding containers, with a positive rate up to 45.6% in used tires in Príncipe, while the native species, Aedes aegypti, preferred natural breeding sources. Phylogenetic analysis based on mitochondrial DNA revealed the introduced populations belonged to a clade involved in the worldwide spread of the species. Aedes albopictus is a public health threat due to its vectorial capacity for various arboviruses. Continuous vector surveillance and implication of interventions, such as source reduction to remove used tires, environmental management, and use of larvicides, were suggested. Aedes albopictus (Skuse, 1894), a mosquito originating in Asia, has been introduced to Africa since the 2000s. The mosquito is not only a nuisance but is capable of transmitting various arboviruses. The current study summarized our entomological surveys in the Democratic Republic of Sao Tome and Principe during 2000 to 2016. Adult mosquitoes were collected by sweep nets, human landing catches, and Centers for Disease Control (CDC) light traps, and the immatures were collected from water-filled habitats at 15 sentinel sites and reared to adulthood. Species identification was performed based on morphologic characteristics. Fragments of the cytochrome C oxidase subunit I (COI) and the Wolbachia surface protein (wsp) genes were amplified for mosquitoes collected in Principe. New records of four mosquito species were reported. Aedes albopictus was identified in 2015. The larvae were found distributed over the nation and were predominately in artificial water-holding containers (488/2698, 18.1%). The highest positive rate was observed in used tires in Príncipe (114/250, 45.6%). Mitochondrial DNA analysis revealed low genetic diversity among the invasive populations, but all tested specimens were superinfected by Wolbachia. The ability of Ae. albopictus to adapt to new environments and its involvement in disease transmission make the surveillance and control of this species particularly important. [ABSTRACT FROM AUTHOR]

Aedes aegypti and Aedes albopictus are responsible for transmitting major human arboviruses such as Dengue, Zika, and Chikungunya, posing a global threat to public health. The lack of etiological treatments and efficient vaccines makes vector control strategies essential for reducing vector population density and interrupting the pathogen transmission cycle. This study evaluated the impact of long-term pyriproxyfen exposure on the genetic structure and diversity of Ae. aegypti and Ae. albopictus mosquito populations. The study was conducted in Manaus, Amazonas, Brazil, where pyriproxyfen dissemination stations have been monitored since 2014 up to the present day. Double digest restriction-site associated DNA sequencing was performed, revealing that despite significant local population reductions by dissemination stations with pyriproxyfen in various locations in Brazil, focal intervention has no significant impact on the population stratification of these vectors in urban scenarios. The genetic structuring level of Ae. aegypti suggests it is more stratified and directly affected by pyriproxyfen intervention, while for Ae. albopictus exhibits a more homogeneous and less structured population. The results suggest that although slight differences are observed among mosquito subpopulations, intervention focused on neighborhoods in a capital city is not efficient in terms of genetic structuring, indicating that larger-scale pyriproxyfen interventions should be considered for more effective urban mosquito control. [ABSTRACT FROM AUTHOR]

Aedes aegypti and Aedes albopictus are predominantly daytime-feeding mosquito species that breed in urban settlements and transmit viral and nematode diseases. Females can feed on a broad range of vertebrate hosts for oogenesis. Research on host-feeding behavior and patterns is important to better understand the transmission cycles of most mosquito-borne diseases and to develop better protection measures. This study investigated the host feeding patterns of Ae. aegypti and Ae. albopictus through both artificial blood feeding and natural feeding techniques and assessed the effect of these methods on mosquito fecundity. Laboratory colonies of both mosquitoes fed on blood from five different hosts (bird, mouse, human, sheep and cow). The artificial blood feeding system consisted of a glass condenser with blood attached to a water bath with warm water circulation and insects fed through a stretched Parafilm membrane over the bottom of the condenser. Natural feeding experiments were performed with paper cups that contained the mosquitoes and were placed over the host's skin for one hour. In the natural feeding method, Ae. aegypti females mostly fed on humans, while in the artificial blood feeding method, they fed on birds. Both human and bird blood sources yielded the highest number of eggs, larvae and pupae for Ae. aegypti. Aedes albopictus preferred humans in the natural feeding method and mice in the artificial blood feeding method. Similarly, egg, larvae and pupae productivity from humans and mice were also high for Ae. albopictus. Both species preferred the artificial feeding method. Our findings show that different blood meal sources and methods affect mosquito fecundity. Such laboratory studies on mosquito feeding patterns can reveal the feeding preference of important vectors and provide vital information for understanding vector and host interactions. [ABSTRACT FROM AUTHOR]

Background: Kadipiro virus (KDV) is a species of the new 12 segmented RNA virus grouped under the genus Seadornavirus within the Reoviridae family. It has previously been isolated or detected from mosquito, Odonata, and bat feces in Indonesia, China, and Denmark, respectively. Here, we describe the isolation and characterization of a viral strain from mosquitoes in Yunnan Province, China. Methods: Mosquitoes were collected overnight using light traps in Shizong county, on July 17, 2023. Virus was isolated from the mosquito homogenate and grown using baby hamster kidney and Aedes albopictus (C6/36) cells. Preliminary identification of the virus was performed by agarose gel electrophoresis (AGE). The full-genome sequences of the strain were determined by full-length amplification of cDNAs and sequenced using next-generation sequencing. Results: We isolated a viral strain (SZ_M48) from mosquitoes (Culex tritaeniorhynchus Giles) that caused cytopathogenic effects in C6/36 cells. AGE analysis indicated a genome consisting of 12 segments of double-stranded RNA that demonstrated a "6-5-1" pattern, similar to the migrating bands of KDV. Phylogenetic analysis based on the full-genome sequence revealed that SZ_M48 is more clustered with KDV isolates from Hubei and Shangdong in China than with Indonesian and Danish strains. The identity between SZ_M48 and SDKL1625 (Shandong, China) is slightly lower than that of QTM27331 (Hubei, China), and the identity with JKT-7075 (Indonesia) and 21164-6/M.dau/DK (Denmark) is the lowest. Conclusion: The full-genome sequence of the new KDV strain described in this study may be useful for surveillance of the evolutionary characteristics of KDVs. Moreover, these findings extend the knowledge about the genomic diversity, potential vectors, and the distribution of KDVs in China. [ABSTRACT FROM AUTHOR]

The spatial pattern of many pathogens that are transmitted by mosquitoes (Diptera: Culicidae) is changing due to globalization and climate change. Thus, surveillance of mosquito vectors is becoming increasingly widespread as basis for risk assessment and control. Species identification by loop‐mediated isothermal amplification (LAMP) assays is simple, fast and reliable. Specific primers for several mosquito species are available (Aedes aegypti, Aedes albopictus, Aedes geniculatus, Aedes japonicus, Aedes koreicus, species of the Anopheles funestus group and An. gambiae complex). In the present work, LAMP assays targeting the rDNA internal transcribed spacer region were developed for Ae. cretinus, a minor sister taxon of Ae. albopictus, and for Culex pipiens/Culex quinquefasciatus and Culex torrentium. The specificities of the primers designed in silico were confirmed by in vitro tests with DNA form non‐target species. Further, the release of DNA from mosquito stages (eggs, larvae, pupae, adults) was investigated, revealing that an incubation for 5 min at 80°C in water is suitable for LAMP. With this method, one specimen (egg, larva, pupa, adult) of a target species could be detected among 49 non‐targets. Thus, the assays are suitable for fast and reliable identification of mosquito species of all life stages by colour change visible to the naked eye, and they are operable under field conditions. [ABSTRACT FROM AUTHOR]

Obligate intracellular endobacteria of the genus Wolbachia are widespread in arthropods and several filarial nematodes. Control programs for vector-borne diseases (dengue, Zika, malaria) and anti-filarial therapy with antibiotics are based on this important endosymbiont. Investigating Wolbachia, however, is impeded by the need for host cells. In this study, the requirements for Wolbachia wAlbB growth in a host cell-free in vitro culture system were characterized via qPCRs. A cell lysate fraction from Aedes albopictus C6/36 insect cells containing cell membranes and medium with fetal bovine serum were identified as requisite for cell-free replication of Wolbachia. Supplementation with the membrane fraction of insect cell lysate increased extracellular Wolbachia replication by 4.2-fold. Replication rates in the insect cell-free culture were lower compared to Wolbachia grown inside insect cells. However, the endobacteria were able to replicate for up to 12 days and to infect uninfected C6/36 cells. Cellfree Wolbachia treated with the lipid II biosynthesis inhibitor fosfomycin had an enlarged phenotype, seen previously for intracellular Wolbachia in C6/36 cells, indicating that the bacteria were unable to divide. In conclusion, we have developed a cell-free culture system in which Wolbachia replicate for up to 12 days, providing an in vitro tool to elucidate the biology of these endobacteria, e.g., cell division by using compounds that may not enter the C6/36 cells. A better understanding of Wolbachia biology, and in particular host-symbiont interactions, is key to the use of Wolbachia in vector control programs and to future drug development against filarial diseases. [ABSTRACT FROM AUTHOR]

The challenge of dengue control due to the unavailability of a specific medication stresses the importance of releasing Wolbachia-carrying mosquitoes through vector control programs. This study investigated the sustainability and frequency of Wolbachia in Wolbachia-dengue-carrying mosquitoes in two dengue hotspot localities in Selangor. A modified sticky ovitrap was used to collect adult mosquitoes in two Wolbachia-releasing areas in Selangor, Kelana Puteri and Kelana D'Putera condominiums. All mosquito samples were subjected to PCR using wsp-specific primers for Wolbachia detection. Dengue virus was detected using RT-PCR, followed by multiplex-PCR. Out of the 80 Aedes spp. collected, Ae. aegypti was the most predominant species. More than one-third of Ae. aegypti were positive for Wolbachia, with 22.9% being superinfected with both Wolbachia A and B strains. About 61.4% of the species were uninfected with Wolbachia. Ae. aegypti carrying the Wolbachia A strain was also identified, which has previously never been reported. This strain was similar to the one found naturally in Ae. albopictus. None of the Ae. aegypti and Ae. albopictus were positive for dengue virus. This study could serve as a model for local researchers or health authorities to design and plan an effective field release and monitoring of Wolbachia-infected mosquitoes. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) and nanoplastics (NPs) are pervasive environmental pollutants that are commonly ingested by organisms at different trophic levels. While the effects of MPs on aquatic organisms have been extensively studied, the impacts of MP ingestion on the host fitness of terrestrial organisms, mainly insects, have been relatively unexplored. This study investigates the effects of MP and NP ingestion on the survivorship and reproduction of 2 medically important mosquito species, Aedes aegypti Linnaeus (Diptera: Culicidae) and Aedes albopictus Skuse (Diptera: Culicidae). Larval and pupal survivorship of Ae. albopictus were not significantly affected by particle size or concentration, but there was a reduction of Ae. aegypti pupal survivorship associated with the ingestion of 0.03 µm NPs. In addition, there was little observed impact of 0.03 µm NP and 1.0 µm MP ingestion on adult survivorship, fecundity, and longevity. To further investigate the effects of MP ingestion on mosquito fitness, we also examined the effects of MPs of varying shape, size, and plastic polymer type on Ae. aegypti immature and adult survivorship. The data suggest that the polymer type and shape did not impact Ae. aegypti immature or adult survivorship. These findings highlight that understanding the effects of microplastic ingestion by mosquitoes may be complicated by the size, composition, and amount ingested. [ABSTRACT FROM AUTHOR]

Dengue fever prevention and control is an urgent need for addressing major infectious diseases in China, and the control strategies need theoretical innovation and technological breakthroughs. Aedes albopictus, the dengue-borne mosquito, exhibits polymorphism in urban environments, resulting in heterogeneous mosquito habitats. This heterogeneity is evident in two aspects: firstly, varying mosquito densities across different habitats, and secondly, differences in vector competence of Aedes albopictus within the same city. The distribution of Aedes albopictus with high vector competence forms discrete "mosquito islands" within the city, analogous to small islands in the sea. Identifying the distribution and scope of these "mosquito islands", combined with vector Aedes daily activity rhythm and innovative ultra-low volume spray technology, can facilitate targeted mosquito control strategies during dengue outbreaks. This approach reduces insecticide spraying, improves mosquito control efficiency, and enables rapid dengue epidemic control. [ABSTRACT FROM AUTHOR]

Objective Aedes albopictus is the main indigenous vector of dengue fever in China. Understanding the spatial genetic structure of Aedes albopictus populations, migration, and gene flow is crucial for the effective prevention and control of vector-borne diseases. Methods From June to September 2023, mosquitoes were collected and morphologically identified from eight different geographic locations across tropical, subtropical, and temperate zones of China. Genomic DNA was extracted from individual female mosquitoes, and the mitochondrial cytochrome C oxidase I gene was amplified and sequenced. Population genetic diversity and associated population characteristics were assessed using software such as BioEdit, DnaSP version 6, Arlequin 3.5, and Mega 11. Results A total of 233 samples from eight Aedes albopictus populations across the three climatic zones were successfully sequenced, yielding a gene fragment sequence of 632 bp with 19 variable sites and no insertion or deletion mutations. A total of 21 haplotypes were detected, with H4 being the dominant shared haplotype among the three climate types. Haplotype diversity (Hd) ranged from 0.191 (Beijing population) to 0.887 (Xishuangbanna population), and nucleotide diversity (Pi) ranged from 0.000 51 (Beijing population) to 0.002 98 (Xishuangbanna population), suggesting high haplotype diversity and low nucleotide diversity in Aedes albopictus. The genetic differentiation indices ranged from 0.026 to 0.641, with higher genetic differentiation between temperate and tropical/subtropical regions. The analysis of molecular variation supported that genetic differentiation mainly came from within populations (60.45%). Conclusions The ecological and climatic environment in the tropics results in higher genetic diversity of Aedes albopictus. Human activities have exacerbated the risk of dengue transmission across different climatic zones. [ABSTRACT FROM AUTHOR]

Objective To explore the genetic diversity of Aedes albopictus populations in plain, hilly, and mountainous areas of Hainan Province, and to analyze the genetic structure of Aedes albopictus populations in different terrain regions of Hainan Province. Methods Aedes albopictus were collected from the plain areas of Sanya and Haikou City, the hills of Danzhou and Tunchang City, and the mountainous areas of Baisha City in Hainan Province. DNA was extracted from a single mosquito and stored in a -80 °C refrigerator for use. Mitochondrial cytochrome C oxidase subunit I (mtDNA-CO I) was amplified by PCR and sequenced. The results were compared on the National Center for Biotechnology Information (NCBI) website, sequence peaks were observed using BioEdit 7.0, genetic diversity parameters were calculated using DnaSP v6, haplotype networks were constructed using PopART 1.7, and analysis of molecular variance (AMOVA) values were calculated using Arlequin to analyze differences between populations. Results A total of 414 mtDNA-CO I sequences were obtained from Aedes albopictus populations in 5 regions, with lengths of 663 bp. All sequences had five mutation sites, with a G+C content of 32.86% and an A+T content of 67.14%, consistent with mitochondrial DNA characteristics. Compared with other populations, the nucleotide diversity of the Danzhou and Tunchang populations in the plain and hilly areas was higher. The average nucleotide differences were higher in the Sanya, Tunchang, and Danzhou populations. Haploid analysis revealed 6 haplotypes, with H02 being the dominant haplotype. The Sanya and Tunchang populations had the highest number of haplotypes, while the Haikou and Sanya populations had exclusive haplotypes. Only the plains populations had unique haplotypes, while the hill and mountainous populations had relatively fewer haplotypes. The neutral results and mismatch distribution map indicated that the population of Aedes albopictus has recently expanded in all regions. The AMOVA value showed that the intra-population differences were greater than the inter-population differences. Conclusions The mtDNA-CO I gene can serve as a molecular marker for studying the genetic diversity of Aedes albopictus populations. The Sanya population in the plain region shows higher genetic diversity, and the two populations in the hilly region also have higher genetic diversity. However, the number of haplotypes is only higher in the Sanya population in the plains and the Danzhou population in the hills. [ABSTRACT FROM AUTHOR]

Objective To investigate the effect of Aedes albopictus salivary protein rAlb-34k2-1-induced mouse splenocytes immune response on dengue virus type 2 (DENV-2)-infected bone marrow-derived macrophages (BMDM) in vitro. Methods The specific cell proliferation response of splenic cells from immunized/non-immunized mice to Alb34k2-1 protein was analyzed using the CCK-8 assay. The antigen-presenting cells (APCs) loaded with mosquito saliva proteins rAlb-34k2-1 protein/rAalb_CTL1 protein were prepared and co-cultured with lymphocytes from spleens of immunized/non-immunized mice. On the one hand, the levels of DENV-2 nucleic acids in BMDM treated with cell supernatants from mixed lymphocyte co-cultures were analyzed by qRT-PCR, and the effect of specific T cell response induced by rAlb-34k2-1 on DENV-2 replication in BMDM was analyzed. On the other hand, the expression of the DENV-2 E gene in BMDM pretreated with rAlb-34k2-1 protein was also evaluated to determine the direct effect of immunized mouse spleen lymphocytes co-cultured at 48 h and 72 h and the effect of spleen lymphocytes from immunized or non-immunized mice on DENV-2 replication in pretreated BMDMs was analyzed. Results Compared to the non-immunized group, the rAlb-34k2-1 protein in vitro caused a specific proliferation of immunized-splenocytes, with a proliferation index (SI) >2 (P<0.000 1).Mixed lymphocyte culture supernatants loaded with rAlb-34k2-1 protein inhibited DENV-2 replication in BMDM, while the mixed lymphocyte culture supernatants loaded with rAalb_CTL1 protein had no such effect (2-ΔΔCT<0.5, P<0.05). There was no difference in DENV-2 intracellular replication in rAlb-34k2-1 pretreated BMDM after co-culture with either immunized-lymphocytes or non-immunized-lymphocytes. Conclusions The supernatant induced by the mouse T cell response to the rAlb-34k2-1 protein can inhibit DENV-2 replication in BMDM cells, providing preliminary experimental evidence to explore the role of mosquito salivary protein-induced immune responses in the pathogenesis of mosquito-borne viruses. [ABSTRACT FROM AUTHOR]

Background: Analyses of the temporal distribution of mosquitoes are presented in statistical charts, but it is difficult to prove in statistics whether differences in peak periods exist among different years or habitats. This study aimed to investigate the application of circular statistics in determining the peak period and a comparison of differences. Methods: Surveillance of adult mosquitoes was conducted twice a month by light traps in five different habitats from March to November for 3 years (2021–2023) in Qingdao, Shandong Province, China. The Kruskal–Wallis test was performed to determine the differences in mosquito density among different years and habitats. Circular statistics and line charts were employed to determine the peak period and a comparison of differences. Results: Among a total of 14,834 adult mosquitoes comprising five mosquito species from four genera, Culex pipiens pallens was dominant and accounted for 89.6% of the specimens identified. Aedes albopictus, Armigeres subalbatus, and Anopheles sinensis made up 5.7%, 4.2%, and 0.5%, respectively. Culex tritaeniorhynchus accounted for less than 0.1%. The mean mosquito density (females/trap night) for the trapping period was 10.3 in 2021, 5.6 in 2022, and 3.6 in 2023. Among five habitats, the highest mosquito density was 8.9 in livestock sheds, followed by 6.8 in parks, 5.9 in rural dwellings, 5.5 in urban dwellings, and 5.4 in hospitals. No statistically significant differences were found among different years (H = 1.96, d.f. 2, P = 0.376) and habitats (H = 0.45, d.f. 4, P = 0.978). Overall, the peak period of mosquito activity fell in the months from June to September. The peak period among 3 years differed significantly (F(2,7022) = 119.17, P < 0.01), but there were no statistically significant differences in peak period among different habitats (F(4,7020) = −159.09, P > 0.05). Conclusion: Circular statistics could be effectively combined with statistical charts to elucidate the peak period of mosquitoes and determine the differences in statistics among different years and habitats. These findings will provide valuable information for mosquito control and public health management. [ABSTRACT FROM AUTHOR]

Simple Summary: Aedes albopictus is an invasive mosquito species with a currently broad distribution range. In this article, we address the role of this mosquito species in the transmission of avian malaria parasites of the genus Plasmodium. To do that, we review the literature and compile existing information on Ae. albopictus–avian Plasmodium interactions to consider the potential impact of its expansion on avian malaria epidemiology. The findings suggest that while experimental infection of certain Plasmodium species is feasible, the occurrence of avian Plasmodium in wild Asian tiger mosquitoes is rare. Mosquitoes' preference for mammals as hosts and their relatively low susceptibility to infection may explain these results. The Asian tiger mosquito (Aedes albopictus) is an invasive mosquito species with a global distribution. This species has populations established in most continents, being considered one of the 100 most dangerous invasive species. Invasions of mosquitoes such as Ae. albopictus could facilitate local transmission of pathogens, impacting the epidemiology of some mosquito-borne diseases. Aedes albopictus is a vector of several pathogens affecting humans, including viruses such as dengue virus, Zika virus and Chikungunya virus, as well as parasites such as Dirofilaria. However, information about its competence for the transmission of parasites affecting wildlife, such as avian malaria parasites, is limited. In this literature review, we aim to explore the current knowledge about the relationships between Ae. albopictus and avian Plasmodium to understand the role of this mosquito species in avian malaria transmission. The prevalence of avian Plasmodium in field-collected Ae. albopictus is generally low, although studies have been conducted in a small proportion of the affected countries. In addition, the competence of Ae. albopictus for the transmission of avian malaria parasites has been only proved for certain Plasmodium morphospecies under laboratory conditions. Therefore, Ae. albopictus may play a minor role in avian Plasmodium transmission in the wild, likely due to its mammal-biased blood-feeding pattern and its reduced competence for the development of different avian Plasmodium. However, further studies considering other avian Plasmodium species and lineages circulating under natural conditions should be carried out to properly assess the vectorial role of Ae. albopictus for the Plasmodium species naturally circulating in its distribution range. [ABSTRACT FROM AUTHOR]

Introduction: Control of the mosquito Aedes albopictus is confounded by its behavior due to females preferring to oviposition in small natural and artificial containers that are often difficult to remove or treat with insecticides. Autodissemination strategies utilizing highly potent insect growth regulators (IGRs) have emerged as promising tools for the control of this container- inhabiting species. The intended goal of autodissemination approaches is to use mosquitoes to self-deliver an IGR to these cryptic oviposition locations. Previous studies have focused on the efficacy of these approaches to impact natural populations, but little focus has been placed on the impacts on mosquitoes when exposed to non-lethal doses of IGRs similar to the levels they would be exposed to with autodissemination approaches. Methods: In this study, the impact of non-lethal doses of pyriproxyfen (PPF) on the reproductive fitness of Ae. albopictus was investigated. Female and male Ae. albopictus mosquitoes were exposed to non-lethal doses of PPF and their fecundity and fertility were measured. To examine the impact of non-lethal doses of PPF, the expression of the ecdysone-regulated genes USP, HR3, and Vg, which are involved in vitellogenesis, was determined. Results: Our results demonstrated a significant reduction in female fecundity and in the blood feeding and egg hatching rates upon exposure to non-lethal doses of PPF. Oocyte development was also delayed in PPF-treated females. Furthermore, exposure to non-lethal doses of PPF altered the expression of the genes involved in vitellogenesis, indicating disruption of hormonal regulation. Interestingly, PPF exposure also reduced the sperm production in males, suggesting a potential semi-sterilization effect. Discussion: These findings suggest that non-lethal doses of PPF could enhance the efficacy of autodissemination approaches by impacting the reproductive fitness of both males and females. However, further research is needed to validate these laboratory findings in field settings and to assess their practical implications for vector control strategies. [ABSTRACT FROM AUTHOR]

Background: The Aedes albopictus mosquito is of medical concern due to its ability to transmit viral diseases, such as dengue and chikungunya. Aedes albopictus originated in Asia and is now present on all continents, with the exception of Antarctica. In Mozambique, Ae. albopictus was first reported in 2015 within the capital city of Maputo, and by 2019, it had become established in the surrounding area. It was suspected that the mosquito population originated in Madagascar or islands of the Western Indian Ocean (IWIO). The aim of this study was to determine its origin. Given the risk of spreading insecticide resistance, we also examined relevant mutations in the voltage-sensitive sodium channel (VSSC). Methods: Eggs of Ae. albopictus were collected in Matola-Rio, a municipality adjacent to Maputo, and reared to adults in the laboratory. Cytochrome c oxidase subunit I (COI) sequences and microsatellite loci were analyzed to estimate origins. The presence of knockdown resistance (kdr) mutations within domain II and III of the VSSC were examined using Sanger sequencing. Results: The COI network analysis denied the hypothesis that the Ae. albopictus population originated in Madagascar or IWIO; rather both the COI network and microsatellites analyses showed that the population was genetically similar to those in continental Southeast Asia and Hangzhou, China. Sanger sequencing determined the presence of the F1534C knockdown mutation, which is widely distributed among Asian populations, with a high allele frequency (46%). Conclusions: These results do not support the hypothesis that the Mozambique Ae. albopictus population originated in Madagascar or IWIO. Instead, they suggest that the origin is continental Southeast Asia or a coastal town in China. [ABSTRACT FROM AUTHOR]

Piercing-sucking insects are extremely efficient vectors of animal and plant pathogens. This group is polyphyletic with the piercing organ highly heterogenous in its structure and morphogenesis, adapted to a specific host and feeding mechanism. For instance, hemimetabolous aphids feed on plant sap from nymphs to adults and they renew their stylets at each molt, thanks to specialized secreting glands. Distinctly, holometabolous mosquitoes have two feeding modes: larvae feed in water by filtering and scraping surfaces with their mouths, while female adults can acquire blood from vertebrate hosts. The pupal metamorphosis allows switching from one feeding habit to another. Here, we present a deep characterization of the biogenesis of the adult mouthparts in parthenogenetic females of the pea aphid Acyrthosiphon pisum (Harris 1776) (Hemiptera: Aphididae) and in females of the mosquito Aedes albopictus (Skuse 1895) (Diptera: Culicidae), investigated using non-invasive X-ray synchrotron-based microtomography. Comparing datasets collected from aphid juvenile and adult stages and from preimaginal and adult stages of the mosquito, we were able to track the morphological changes of secreting glands and the synthesis of the adult stylet in aphid heads and to follow the de novo formation of mosquito mouthparts in pupae. Our study provides a baseline for investigating the evolution and the development of piercing-sucking mouthparts and to better understand how morphogenesis works in insects. [ABSTRACT FROM AUTHOR]