Wing morphometric variability in Aedes aegypti (Diptera: Culicidae) from different urban built environments

Resolution of cryptic mosquito species through wing morphometrics

Mosquitoes are medically important insects, and accurate species identification is crucial to understanding vector biology, forming the cornerstone of successful vector control programs. Identification is difficult owing to morphologically similar species. Wing morphometrics can provide a simple, fast, and accurate way to classify species, and using it as a method to differentiate vector species among its cryptic congeners has been underexplored. Using a total of 227 mosquitoes and 20 landmarks per specimen, we demonstrated the utility of wing morphometrics in differentiating species two groups occurring in sympatry - Culex (Culex) vishnui group and Culex (Lophoceraomyia) subgenus, as well as explored population-level variation in the wing shape of Aedes albopictus across habitats. Cytochrome oxidase subunit I (COI) gene region was sequenced to validate the morphological and morphometric identification. Procrustes ANOVA regression and CVA based on wing shape reflected that the wing landmarks across all species differed significantly, and leave-one-out cross validation revealed an overall high accuracy of >97% for the two Culex groups. Wing morphometrics uncovered population-level variation within Aedes albopictus, but cross validation accuracy was low. Overall, we show that wing geomorphometric analysis is able to resolve cryptic Culex species (including vectors) occurring sympatrically, and is a robust tool for identifying mosquitoes reliably.

Influence of insular conditions on wing phenotypic variation in two dominant mosquito vectors, Aedes albopictus and Armigeres subalbatus (Diptera: Culicidae), in the border archipelagos of Thailand

Insects geographically separated into island and mainland populations often exhibit phenotypic variations, a phenomenon known as insular conditions. These conditions can lead to rapid evolutionary changes that affect the morphological characteristics of mosquito vectors. Nevertheless, studies that specifically examine phenotype differences between island and mainland mosquito populations have been limited. In this study, wing variation in size and shape was investigated using the geometric morphometric (GM) technique in two dominant mosquito vectors, Aedes albopictus and Armigeres subalbatus, in the Ranong and Trat archipelagos of Thailand. Significant differences in average wing centroid size (CS) were found in 6 out of 15 population pairs for Ae. albopictus (p < 0.05) and in 5 population pairs for Ar. subalbatus (p < 0.05). After removing the allometric effect, canonical variate analyses (CVA) based on wing shape analysis revealed overlap across all populations for both Ae. albopictus and Ar. subalbatus. However, the statistical analysis indicated that Ar. subalbatus exhibited wing shape differences across all populations (p < 0.05), and most Ae. albopictus populations also displayed distinct wing shapes (p < 0.05), except for the populations from Chang Island and the mainland of Ranong, which showed no significant differences (p > 0.05). These findings enhance our understanding of mosquito adaptability in island regions and provide valuable data for the surveillance and monitoring of vector evolution.

Population genetic structure and wing geometric morphometrics of the filarial vector Armigeres subalbatus (Diptera: Culicidae) in Thailand

Armigeres subalbatus (Diptera: Culicidae) is a mosquito species of significant medical and veterinary importance. It is widely distributed across Southeast and East Asia and is commonly found throughout Thailand. This study assessed the genetic diversity and population structure of Ar. subalbatus in Thailand using the cytochrome c oxidase subunit I (COI) gene sequences. Additionally, wing shape variations among these populations were examined using geometric morphometrics (GM). Our results demonstrated that the overall haplotype diversity (Hd) was 0.634, and the nucleotide diversity (π) was 0.0019. Significant negative values in neutrality tests (p < 0.05) indicate that the Ar. subalbatus populations in Thailand are undergoing a phase of expansion following a bottleneck event. The mismatch distribution test suggests that the populations may have started expanding approximately 16,678 years ago. Pairwise genetic differentiation among the 12 populations based on Fst revealed significant differences in 32 pairs (p < 0.05), with the degree of differentiation ranging from 0.000 to 0.419. The GM analysis of wing shape also indicated significant differences in nearly all pairs (p < 0.05), except for between populations from Nakhon Pathom and Samut Songkhram, and between those from Chiang Mai and Mae Hong Son, suggesting no significant difference due to their similar environmental settings. These findings enhance our understanding of the population structure and phenotypic adaptations of mosquito vectors, providing vital insights for the formulation of more efficacious vector control strategies.

Insights into the mitochondrial cytochrome oxidase I (mt-COI) gene and wing morphometrics of Anopheles baimaii (Diptera: Culicidae) in malaria-endemic islands of Thailand

Anopheles baimaii (Diptera: Culicidae) significantly contributes to the transmission of parasites causing malaria in Southeast Asia and South Asia. This study examined the morphological (wing shape) and molecular (mitochondrial gene) variations of An. baimaii in four of Thailand's border islands, and also investigated the presence of Plasmodium parasites in these mosquitoes. No Plasmodium infections were detected in the samples. Significant differences in wing shape were observed in most island populations (p < 0.05). A single-linkage tree, constructed using Mahalanobis distances, clustered the populations into two groups based on geographical locations. Genetic variation in An. baimaii was also analyzed through cytochrome c oxidase subunit I (COI) gene sequences. This analysis identified 22 segregating sites and a low nucleotide diversity of 0.004. Furthermore, 18 distinct haplotypes were identified, indicating a high haplotype diversity of 0.825. Neutrality tests for the overall population revealed a significantly negative Fu's Fs value (-5.029), indicating a population expansion. In contrast, Tajima's D yielded a negative value (-1.028) that did not reach statistical significance. The mismatch distribution analysis exhibited a bimodal pattern, and the raggedness index was 0.068, showing no significant discrepancy (p = 0.485) between observed and expected distributions. Pairwise genetic differentiation assessments demonstrated significant differences between all populations (p < 0.05). These findings provide valuable insights into the COI gene and wing morphometric variations in An. baimaii across Thailand's islands, offering critical information for understanding the adaptations of this malaria vector and guiding future comprehensive research.

Genetic diversity and wing geometric morphometrics among four populations of Aedes aegypti (Diptera: Culicidae) from Benin

BACKGROUND

The impact of the arbovirus vector Aedes aegypti is of major concern for global public health as the viruses that it transmits affect millions of people each year worldwide. Originating in Africa, Ae. aegypti has now spread throughout much of the world. While the genetic makeup of Ae. aegypti in the New World has been extensively studied, there is limited knowledge on its genetic diversity in Africa, particularly at a microgeographical level.

METHODS

We investigated mitochondrial cytochrome oxidase I of four Ae. aegypti populations from Benin and employed wing morphometric analyses as a cost-effective and reliable tool to explore population structure. Our sampling encompassed various areas of Benin, from the southern to the northern borders of the country, and included urban, semi-urban, and sylvatic sites.

RESULTS

We observed a notable level of genetic diversity (haplotype diversity of 0.8333) and nucleotide diversity (0.00421986), and identified seven distinct haplotypes. Sylvatic and semi-urban sites exhibited a greater number of haplotypes compared to urban sites. Utilizing 18 wing landmarks, we calculated the centroid size, which revealed significant variation among the three landscape types. However, principal component analysis, employed to assess wing shape variation, did not demonstrate significant differences between populations based on landscape type.

CONCLUSIONS

Our findings indicate substantial genetic and morphological diversity among Ae. aegypti populations in Benin, and provide insight into important biological characteristics of these populations with respect to their potential to transmit viruses. To the best of our knowledge, this is the first study undertaken in Africa to integrate genetics with morphology to analyse the population structure of the major arbovirus vector Ae. aegypti.

Using machine learning to understand microgeographic determinants of the Zika vector, Aedes aegypti

There are limited data on why the 2016 Zika outbreak in Miami-Dade County, Florida was confined to certain neighborhoods. In this research, Aedes aegypti, the primary vector of Zika virus, are studied to examine neighborhood-level differences in their population dynamics and underlying processes. Weekly mosquito data were acquired from the Miami-Dade County Mosquito Control Division from 2016 to 2020 from 172 traps deployed around Miami-Dade County. Using random forest, a machine learning method, predictive models of spatiotemporal dynamics of Ae. aegypti in response to meteorological conditions and neighborhood-specific socio-demographic and physical characteristics, such as land-use and land-cover type and income level, were created. The study area was divided into two groups: areas affected by local transmission of Zika during the 2016 outbreak and unaffected areas. Ae. aegypti populations in areas affected by Zika were more strongly influenced by 14- and 21-day lagged weather conditions. In the unaffected areas, mosquito populations were more strongly influenced by land-use and day-of-collection weather conditions. There are neighborhood-scale differences in Ae. aegypti population dynamics. These differences in turn influence vector-borne disease diffusion in a region. These results have implications for vector control experts to lead neighborhood-specific vector control strategies and for epidemiologists to guide vector-borne disease risk preparations, especially for containing the spread of vector-borne disease in response to ongoing climate change.

Phenotypic Variations of Aedes aegypti Populations and Egg Abundance According to Environmental Parameters in Two Dengue-Endemic Ecoregions in Paraguay

Dengue in Paraguay is an endemic disease of public health importance. Several studies suggest that an increased density of Aedes aegypti and the presence of dengue cases may be associated with climatic conditions. This study aimed to establish the phenotypic variations of Ae. aegypti from four cities (Asunción, Itauguá, Minga Guazú, and Ciudad del Este) and the potential association of environmental variables with the number of eggs in capture sites. Eleven morphometric phenotypic characters were evaluated, and environmental data were obtained from Earth Engine and local meteorological stations. An analysis was carried out using principal component analysis and linear discriminant analysis, and we estimated the correlation using [relative humidity, Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI)] between variables and the number of eggs in each site. Differences in mean NDVI and NDWI between cities and their relationship with the morphometric performance of individuals were also assessed. The study demonstrated morphometric variations between the populations of Ae. aegypti from two ecoregions, with the Litoral ecoregion populations presented a greater phenotypic variation than those observed in the Alto Paraná ecoregion. Significant statistical associations were registered between the number of eggs with relative humidity (r = -0.45) and the NDVI at 100 meters from the capture points (r = -0.61) for Minga Guazú, and with the NDWI at 100 meters (r = 0.54) for Ciudad del Este. Future studies on these Ae. aegypti populations, and its dispersion could contribute to improve vector control measures and foster future genetic studies.

The Head of Fannia pusio (Fanniidae: Diptera) as A Novel Source of Morphometric Data for Assessing of Variation Along Geographic and Biological Lines

Fannia Robineau-Desvoidy, 1830 is the most diverse genus in the family Fanniidae (Diptera), with 288 species, many of which are include many of sanitary, economic and legal interest. The morphological homogeneity within the genus often makes species determination difficult. The best option for correct identification is to combine molecular and morphological analyses. The variation in the shape of a selection of body characters can be assessed by Geometric Morphometrics using the head as an innovative structure. Sex must be accounted for as a key covariate in this kind of study, since Fannia, as many other Diptera, has a sexually dimorphic head structure, with holoptic males and dicoptic females. Firstly, we analysed a set of Fannia sp. specimens sampled across the Iberian Peninsula (2012-2015), of which Fannia pusio (Wiedemann, 1830) was found to be the most abundant species. Our analyses provide significant morphological information. Fannia pusio exhibits clear intraspecific morphometric variation along an Iberian-wide East-West axis. A similar pattern emerged when comparing a laboratory-bred colony and wild samples.

Urbanization favors the proliferation of Aedes aegypti and Culex quinquefasciatus in urban areas of Miami-Dade County, Florida

Urbanization processes are increasing globally. Anthropogenic alterations in the environment have profound effects on biodiversity. Decreased biodiversity due to biotic homogenization processes as a consequence of urbanization often result in increased levels of mosquito vector species and vector-borne pathogen transmission. Understanding how anthropogenic alterations in the environment will affect the abundance, richness, and composition of vector mosquito species is crucial for the implementation of effective and targeted mosquito control strategies. We hypothesized that anthropogenic alterations in the environment are responsible for increasing the abundance of mosquito species that are adapted to urban environments such as Aedesaegypti and Culexquinquefasciatus. Therefore, our objective was to survey mosquito relative abundance, richness, and community composition in Miami-Dade County, Florida, in areas with different levels of urbanization. We selected 24 areas, 16 remote areas comprised of natural and rural areas, and 8 urban areas comprised of residential and touristic areas in Miami-Dade County, Florida. Mosquitoes were collected weekly in each area for 24 h for 5 consecutive weeks from August to October 2020 using BG-Sentinel traps baited with dry ice. A total of 36,645 mosquitoes were collected, from which 34,048 were collected in the remote areas and 2,597 in the urban areas. Our results show a clear and well-defined pattern of abundance, richness, and community composition according to anthropogenic modifications in land use and land cover. The more urbanized a given area the fewer species were found and those were primary vectors of arboviruses, Ae.aegypti and Cx.quinquefasciatus.

Invasion, establishment, and spread of invasive mosquitoes from the Culex coronator complex in urban areas of Miami-Dade County, Florida

Species from the Culex coronator complex are Neotropical species and potential vectors of Saint Louis and West Nile viruses. Culex coronator was first described in Trinidad and Tobago in the early twentieth century and since then it has invaded and has been reported established in most countries of the Americas. Species from the Culex coronator complex were first detected in the United States in the state of Louisiana in 2004 and were subsequently detected in Florida in 2005, reaching Miami-Dade County in 2008. We hypothesize that species from the Cx. coronator complex are adapting to urban environments in Miami-Dade County, Florida, and are becoming more present and abundant in these areas. Therefore, our objective was to investigate the patterns of the presence and abundance of species from the Cx. coronator complex in the urban areas of Miami-Dade County. Here we used weekly data comprised of 32 CDC traps from 2012 to 2020 and 150 BG-Sentinel traps from 2016 to 2020. A total of 34,146 female mosquitoes from the Cx. coronator complex were collected, 26,138 by CDC traps and 8008 by BG-Sentinel traps. While the number of CDC traps that were positive was relatively constant at 26–30 positive traps per year, the number of positive BG-Sentinel traps varied substantially from 50 to 87 positive traps per year. Furthermore, the heat map and logistic general linear model for repeated measures analyses showed a significant increase in both the distribution and abundance of mosquitoes from the Cx. coronator complex, indicating that these species are becoming more common in anthropized habitats being able to thrive in highly urbanized areas. The increase in the distribution and abundance of species from the Cx. coronator complex is a major public health concern. The ability of species from the Cx. coronator complex to benefit from urbanization highlights the need to better understand the mechanisms of how invasive vector mosquito species are adapting and exploiting urban habitats.

Landmark-based geometric morphometric analysis of wing size and wing shape among Aedes albopictus (Skuse, 1894) populations in Turkey

Aedes albopictus (Skuse, 1894) has a widespread distribution that includes both temperate and tropical climates. It is a potential vector of several important worldwide arboviruses, including chikungunya, zika, and dengue, and its geographical distribution expands rapidly. Despite its vectorial importance, the bioecological features of this species in newly established environments are still not very well known. Thus, this study investigated phenotypic variations among Ae. albopictus populations from different regions in Turkey. This is the first comparative morphological study of Ae. albopictus populations in Turkey. The procrustes distances phenogram derived from wing data indicates that the shape differences among some populations and the population from the Aegean coast differ from the Black Sea populations. Size differences were also detected between some populations.

Study of Mosquito Aerodynamics for Imitation as a Small Robot and Flight in a Low-Density Environment

In terms of their flight and unusual aerodynamic characteristics, mosquitoes have become a new insect of interest. Despite transmitting the most significant infectious diseases globally, mosquitoes are still among the great flyers. Depending on their size, they typically beat at a high flapping frequency in the range of 600 to 800 Hz. Flapping also lets them conceal their presence, flirt, and help them remain aloft. Their long, slender wings navigate between the most anterior and posterior wing positions through a stroke amplitude about 40 to 45°, way different from their natural counterparts (>120°). Most insects use leading-edge vortex for lift, but mosquitoes have additional aerodynamic characteristics: rotational drag, wake capture reinforcement of the trailing-edge vortex, and added mass effect. A comprehensive look at the use of these three mechanisms needs to be undertaken-the pros and cons of high-frequency, low-stroke angles, operating far beyond the normal kinematic boundary compared to other insects, and the impact on the design improvements of miniature drones and for flight in low-density atmospheres such as Mars. This paper systematically reviews these unique unsteady aerodynamic characteristics of mosquito flight, responding to the potential questions from some of these discoveries as per the existing literature. This paper also reviews state-of-the-art insect-inspired robots that are close in design to mosquitoes. The findings suggest that mosquito-based small robots can be an excellent choice for flight in a low-density environment such as Mars.

Wing Morphometrics of Aedes Mosquitoes from North-Eastern France

BACKGROUND

In the context of the increasing circulation of arboviruses, a simple, fast and reliable identification method for mosquitoes is needed. Geometric morphometrics have proven useful for mosquito classification and have been used around the world on known vectors such as Aedes albopictus. Morphometrics applied on French indigenous mosquitoes would prove useful in the case of autochthonous outbreaks of arboviral diseases.

METHODS

We applied geometric morphometric analysis on six indigenous and invasive species of the Aedes genus in order to evaluate its efficiency for mosquito classification.

RESULTS

Six species of Aedes mosquitoes (Ae. albopictus, Ae. cantans, Ae. cinereus, Ae. sticticus, Ae. japonicus and Ae. rusticus) were successfully differentiated with Canonical Variate Analysis of the Procrustes dataset of superimposed coordinates of 18 wing landmarks.

CONCLUSIONS

Geometric morphometrics are effective tools for the rapid, inexpensive and reliable classification of at least six species of the Aedes genus in France.

The influence of larval density on triacylglycerol content in Aedes aegypti (Linnaeus) (Diptera: Culicidae)

Given the importance of Aedes aegypti as an arbovirus vector, understanding the impact of population density during larval development is fundamental to improve control methods. The aims of this study were to analyze the effects of larval density on the triacylglycerol (TAG) reserves, fecundity, and the size of mosquitos. To evaluate the influence of density on the amount of TAG in the different stages of development of A. aegypti, the larvae were reared in densities of 0.04, 0.32, and 0.8 larvae/ml, represented by D1, D2, and D3, respectively. Larval rearing density affected the amount of TAG in the different developmental stages of this insect. The group reared with the highest population density (D3) presented greater storage of TAG, except when analyzing the amount of TAG μg/protein in the fat body of blood-fed females. In addition, it was possible to observe higher resistance to fasting and a greater number of eggs laid. Insects reared in D2 and D3 were larger than those in the D1 group. This study provides interesting data for future investigations on how the density of larval rearing affects the lipid metabolism for synthesis and mobilization of TAG stored in A. aegypti and how it influences size and reproduction.

Another dengue fever outbreak in Eastern Ethiopia-An emerging public health threat

Background

Dengue Fever (DF) is a viral disease primarily transmitted by Aedes (Ae.) aegypti mosquitoes. Outbreaks in Eastern Ethiopia were reported during 2014–2016. In May 2017, we investigated the first suspected DF outbreak from Kabridahar Town, Somali region (Eastern Ethiopia) to describe its magnitude, assess risk factors, and implement control measures.

Methods

Suspected DF cases were defined as acute febrile illness plus ≥2 symptoms (headache, fever, retro-orbital pain, myalgia, arthralgia, rash, or hemorrhage) in Kabridahar District residents. All reported cases were identified through medical record review and active searches. Severe dengue was defined as DF with severe organ impairment, severe hemorrhage, or severe plasma leakage. We conducted a neighborhood-matched case-control study using a subset of suspected cases and conveniently-selected asymptomatic community controls and interviewed participants to collect demographic and risk factor data. We tested sera by RT-PCR to detect dengue virus (DENV) and identify serotypes. Entomologists conducted mosquito surveys at community households to identify species and estimate larval density using the house index (HI), container index (CI) and Breteau index (BI), with BI≥20 indicating high density.

Results

We identified 101 total cases from May 12–31, 2017, including five with severe dengue (one death). The attack rate (AR) was 17/10,000. Of 21 tested samples, 15 (72%) were DENV serotype 2 (DENV 2). In the case-control study with 50 cases and 100 controls, a lack of formal education (AOR [Adjusted Odds Ratio] = 4.2, 95% CI [Confidence Interval] 1.6–11.2) and open water containers near the home (AOR = 3.0, 95% CI 1.2–7.5) were risk factors, while long-lasting insecticide treated-net (LLITN) usage (AOR = 0.21, 95% CI 0.05–0.79) was protective. HI and BI were 66/136 (49%) and 147 per 100 homes (147%) respectively, with 151/167 (90%) adult mosquitoes identified as Ae. aegypti.

Conclusion

The epidemiologic, entomologic, and laboratory investigation confirmed a DF outbreak. Mosquito indices were far above safe thresholds, indicating inadequate vector control. We recommended improved vector surveillance and control programs, including best practices in preserving water and disposal of open containers to reduce Aedes mosquito density.

In 2017 an outbreak of Dengue fever (DF) was reported in Kabridahar Town, Ethiopia. This mosquito transmitted disease was recently detected in Ethiopia only four years prior, with this being the first time it was identified in the area. In response, our team was dispatched to confirm the presence of the disease, identify potential causes, and implement mitigation and control measures. We identified and compared suspected cases and suspected non-cases to identify the potential risk factors of infection. Laboratory confirmation of infection and disease-type was also performed. Due to the entomological nature of disease transmission, additional entomological investigations were conducted at the households of both groups to understand its influence at the household level. Through these measures, we were able to establish the presence of DF in Kabridahar Town and identify risk factors leading to infection. Risk factors included a lack of formal education and open water containers near the home, while the presence of long-lasting insecticide-treated nets were found to be protective. Mitigation and control measures were implemented to combat or promote the identified risk and protective factors respectively. Cases counts began to reduce five days after the onset of these measures. Recommendations were made based on our findings to prevent future outbreaks. The last case was recorded ten days after implementation of the mitigation and control measures.

Wing geometry and genetic analyses reveal contrasting spatial structures between male and female Aedes aegypti (L.) (Diptera: Culicidae) populations in metropolitan Manila, Philippines

The population genetic structure of Aedes aegypti (Linnaeus, 1762) has been studied in order to understand its role as an efficient vector. Several studies utilized an integrative approach; to combine genetic and phenotypic data to determine its population structure but these studies have only focused on female populations. To address this particular gap, our study compared the population variability and structuring between its male and female populations using phenotypic and genetic data from a highly-urbanized and dengue-endemic region of the Philippines, Metropolitan Manila. Five mosquito populations comprised of female (n = 137) and male (n = 49) adult mosquitoes were used in this study. All mosquito individuals underwent geometric morphometric (26 landmarks), and genetic (11 microsatellite loci) analyses. Results revealed that F_ST estimates (genetic) were 0.055 and 0.009 while Q_ST estimates (phenotypic) were 0.318 and 0.309 in in male and female populations, respectively. Wing shape variation plots showed that male populations were distinctly separated from each other while female populations overlapped. Similarly, discriminant analysis of principal components using genetic data revealed that male populations were also distinctly separated from each other while female populations showed near-overlapping populations. Genetic and phenetic dendrograms showed the formation of two groups in male populations but no groups in female populations. Further analysis indicated a significant correlation (r = 0.68, p = 0.02) between the genetic and phenetic distances of male populations. Bayesian analysis using genetic data also detected multiple clusters in male (K = 3) and female (K = 2) populations, while no clusters were detected using the phenotypic data from both sexes. Our results revealed contrasting phenotypic and genetic patterns between male and female Ae. aegypti, indicating that male populations were more spatially structured than female populations.

Microgeographic Wing-Shape Variation in Aedes albopictus and Aedes scapularis (Diptera: Culicidae) Populations

Aedes albopictus and Aedes scapularis are vectors of several arboviruses, including the dengue, chikungunya, and Rocio virus infection. While Ae. albopictus is a highly invasive species native to Asia and has been dispersed by humans to most parts of the world, Ae. scapularis is native to Brazil and is widely distributed in the southeast of the country. Both species are highly anthropophilic and are often abundant in places with high human population densities. Because of the great epidemiological importance of these two mosquitoes and the paucity of knowledge on how they have adapted to different urban built environments, we investigated the microgeographic population structure of these vector species in the city of São Paulo, Brazil, using wing geometric morphometrics. Females of Ae. albopictus and Ae. scapularis were collected in seven urban parks in the city. The right wings of the specimens were removed and digitized, and eighteen landmarks based on vein intersections in the wing venation patterns were used to assess cross-sectional variation in wing shape and size. The analyses revealed distinct results for Ae. albopictus and Ae. scapularis populations. While the former had less wing shape variation, the latter had more heterogeneity, indicating a higher degree of intraspecific variation. Our results indicate that microgeographic selective pressures exerted by different urban built environments have a distinct effect on wing shape patterns in the populations of these two mosquito species studied here.

Wing geometric morphometrics for identification of mosquito species (Diptera: Culicidae) of neglected epidemiological importance

Culicidae comprises more than 3500 species, some of which are responsible for the spread of various human diseases, causing millions of deaths worldwide. Correct identification of these species is essential for the development of surveillance and control strategies. The most common method of mosquito identification is based on specific traits of the external morphology of species. However, identification of mosquitoes by morphological characters can be inaccurate or even unfeasible if the specimen is damaged or there is a lack of distinguishing features, as in the case of cryptic species complexes. Wing geometric morphometrics is a reliable, affordable tool for the identification of mosquito species, including sibling species. More importantly, it can be used in addition to both traditional morphologic identification methods as well as genetic approaches. Here, wing geometric morphometrics was used to identify sixteen mosquito species from eight genera: Aedes, Coquillettidia, Culex, Limatus, Mansonia, Psorophora, Runchomyia, and Wyeomyia. The 390 specimens used here were collected in São Paulo, Brazil using CDC traps, aspiration, and Shannon traps. Allometry was assessed by multivariate regression of the Procrustes coordinates on centroid size followed by canonical variate analysis and a pairwise cross-validated reclassification test. A Neighbor-Joining tree based on Mahalanobis distances was constructed with 1,000 bootstrap replicates using MorphoJ 1.02 and Past 2.17c. The canonical variate analysis of genera resulted in distinct clusters for Culex, Limatus, and Psorophora and partial overlapping between Aedes, Coquilettidia, and Mansonia, and between Runchomyia and Wyeomyia. Pairwise cross-validated reclassification tests indicated that genera were identified with an accuracy of at least 99% and subgenera with a mean accuracy of 96% and that in 160 of the 240 possible comparisons species were identified with an accuracy of 100%. Our results show that the eight genera in the study were correctly distinguished by wing shape, as were subgenera and most species, demonstrating that wing geometric morphometrics can be used for the identification of the mosquito species studied here.

Proliferation of Aedes aegypti in urban environments mediated by the availability of key aquatic habitats

Aedes aegypti is the main vector of dengue, Zika, chikungunya, and yellow fever viruses. Controlling populations of vector mosquito species in urban environments is a major challenge and being able to determine what aquatic habitats should be prioritized for controlling Ae. aegypti populations is key to the development of more effective mosquito control strategies. Therefore, our objective was to leverage on the Miami-Dade County, Florida immature mosquito surveillance system based on requested by citizen complaints through 311 calls to determine what are the most important aquatic habitats in the proliferation of Ae. aegypti in Miami. We used a tobit model for Ae. aegypti larvae and pupae count data, type and count of aquatic habitats, and daily rainfall. Our results revealed that storm drains had 45% lower percentage of Ae. aegypti larvae over the total of larvae and pupae adjusted for daily rainfall when compared to tires, followed by bromeliads with 33% and garbage cans with 17%. These results are indicating that storm drains, bromeliads and garbage cans had significantly more pupae in relation to larvae when compared to tires, traditionally know as productive aquatic habitats for Ae. aegypti. Ultimately, the methodology and results from this study can be used by mosquito control agencies to identify habitats that should be prioritized in mosquito management and control actions, as well as to guide and improve policies and increase community awareness and engagement. Moreover, by targeting the most productive aquatic habitats this approach will allow the development of critical emergency outbreak responses by directing the control response efforts to the most productive aquatic habitats.

The Global Expansion of Dengue: How Aedes aegypti Mosquitoes Enabled the First Pandemic Arbovirus

Dengue is an emerging viral disease principally transmitted by the Aedes (Stegomyia) aegypti mosquito. It is one of the fastest-growing global infectious diseases, with 100-400 million new infections a year, and is now entrenched in a growing number of tropical megacities. Behind this rapid rise is the simple adaptation of Ae. aegypti to a new entomological niche carved out by human habitation. This review describes the expansion of dengue and explores how key changes in the ecology of Ae. aegypti allowed it to become a successful invasive species and highly efficient disease vector. We argue that characterizing geographic heterogeneity in mosquito bionomics will be a key research priority that will enable us to better understand future dengue risk and design control strategies to reverse its global spread.