Comparative morphology of the pyloric armature of adult mosquitoes (Diptera: Culicidae)

The structure of the pyloric armature, hypothesized to aid in blood-meal digestion or parasite resistance, was compared quantitatively among the following 8 species in 5 genera of adult mosquitoes from the southeastern United States: Aedes albopictus, Aedes japonicus, Aedes triseriatus, Anopheles punctipennis, Culex pipiens s.l., Culex restuans, Orthopodomyia signifera, and Toxorhynchites rutilus. Females differed significantly among species in the structure of spines composing the armature, with Aedes spp. forming one general group, Culex spp. another, and An. punctipennis and Or. signifera a third. Relationships of species based on structural characters of the armature were consistent with recent culicid phylogenies. Although pyloric armature has been noted in mosquitoes and other insects, this is the first quantitative investigation of the mosquito pyloric armature.     

Horizontal distribution affects the vertical distribution of native and invasive container‐inhabiting Aedes mosquitoes within an urban landscape

The vertical dimension constitutes an important niche axis along which mosquitoes may adjust their distribution. Here, we evaluated whether the vertical distribution of container‐inhabiting Aedes mosquitoes differs along a gradient of anthropogenic land‐use intensity within an urban landscape. Using a pulley system, we hung oviposition cups at three heights (ground level, 4.5, and 9 m) and in three habitats: forest, park, and a built environment. We hypothesized that mosquito abundance and diversity would be highest in the least disturbed forest habitat, decrease in the park, and be lowest at the UNC‐Greensboro campus. We also expected Aedes albopictus (Skuse) and Ae. triseriatus (Say) to mainly oviposit at ground level and Ae. hendersoni (Cockerell) at canopy height. Aedes albopictus was the most common species (68.8%) collected in all three habitat types and was the only species found in the built environment. In that habitat, Ae. albopictus exhibited a bimodal distribution with the lowest activity at the intermediate height (4.5 m). Aedes triseriatus (28.9%) did not differ in egg abundance between the forest and park habitats but did exhibit diverse vertical habitat use while avoiding the canopy in the park habitat. Aedes hendersoni (2.3%) was the most sylvatic species and oviposited only at ground level. Our results indicate that the vertical distribution of mosquitoes is affected by the type of habitat in which they occur, and that this variation could be driven via local‐scale modification of microclimatic factors.     

Loop‐mediated isothermal amplification (LAMP) for the identification of invasive Aedes mosquito species

Invasive Aedes mosquito species (Diptera: Culicidae) are of public health concern in Europe because they are either recognized or potential vectors of pathogens. Loop‐mediated isothermal amplification (LAMP) is a rapid and simple method for amplifying DNA with high specificity and efficiency, with the technique having potential for application in the field, including in high‐throughput format. Specific LAMP assays based on rDNA internal transcribed spacers 1 or 2 sequences, considering intraspecies variability at these loci, were developed for Aedes aegypti, Aedes albopictus, Aedes japonicus, Aedes koreicus and the indigenous Aedes geniculatus. No such assays could be developed for Aedes atropalpus and Aedes triseriatus because both loci were too short to serve as target. The assays rely on the clearly visible colour change from violet to sky blue after successful amplification. Sensitivity of egg detection was confirmed with ratios of up to one mosquito egg in 99 other eggs. Simple sample preparation of adults or eggs by mechanical homogenization in water required an additional heat treatment or centrifugation step to avoid non‐specific colour changes. Thus, further technical improvements are needed to render these assays truly field‐applicable, which would greatly facilitate surveillance of these invasive mosquito species and allow for prompt implementation of control measures.     

Nestedness patterns of container-dwelling mosquitoes: effects of larval habitat within variable terrestrial matrices

Distributions of mosquito larvae likely are a consequence of multiple factors, although two commonly studied factors (quality of the larval environment and the terrestrial matrix in which these habitats reside) have rarely and simultaneously been varied in the field to understand distributions of larvae. We monitored aquatic containers of two leaf detritus levels within a forest, prairie, and industrial habitat across five months to understand the temporal and spatial colonization of aquatic invertebrates in Northcentral Illinois, USA. Data were collected monthly on mosquito populations and the composition of other invertebrates colonizing containers. Overall, six species of mosquitoes colonized containers, with Culex restuans and Aedes triseriatus having the highest relative abundances. There were strong seasonal abundance patterns for these two mosquito species, with the dominant species changing over time in the forest habitat. The responses of other mosquito taxa were more variable, with abundances reflective of either the terrestrial matrix or larval habitat quality. High detritus containers supported the highest abundances of most species encountered, regardless of habitat. Non-mosquito taxa were less common numerically, but analyses suggested that some taxa, such as syrphid larvae, often co-occurred with mosquitoes. Nested subset analysis indicated communities were strongly nested, and that both habitat type and detritus level were important in explaining nested patterns of aquatic invertebrates. Our data show that both the larval habitat and the surrounding terrestrial matrix shape patterns of container mosquitoes, and that other container invertebrates vary in similar ways as mosquitoes. Handling editor: K. Martens     

Midgut fungal and bacterial microbiota of Aedes triseriatus and Aedes japonicus shift in response to La Crosse virus infection

Understanding how midgut microbial communities of field‐collected mosquitoes interact with pathogens is critical for controlling vector infection and disease. We used 16S rRNA and internal transcribed spacer sequencing to characterize the midgut bacterial and fungal communities of adult females of Aedes triseriatus and Aedes japonicus collected as pupae in tree holes, plastic bins and waste tires and their response to La Crosse virus (LACV) infection. For both mosquito species and across all habitat and virus treatments, a total of 62 bacterial operational taxonomic units (OTUs) from six phyla and 21 fungal OTUs from two phyla were identified. The majority of bacterial (92%) and fungal (71%) OTUs were shared between the mosquito species; however, several OTUs were unique to each species. Bacterial and fungal communities of individuals that took either infectious or noninfectious bloodmeals were less diverse and more homogeneous compared to those of newly emerged adults. Interestingly, LACV‐infected A. triseriatus and A. japonicus had higher bacterial richness and lower fungal richness compared to individuals that took a noninfectious bloodmeal, suggesting that viral infection was associated with an increase in bacterial OTUs and a decrease in fungal OTUs. For both mosquito species, several OTUs were identified that had both high fidelity and specificity to mosquito midguts that were infected with LACV. Overall, these findings demonstrate that bacterial and fungal communities that reside in mosquito midguts respond to host diet and viral infection and could play a role in modulating vector susceptibility to LACV.     

Variation in performance of two co‐occurring mosquito species across diverse resource environments: insights from nutrient and stable isotope analyses

1. Inputs of animal and plant detritus are the main energy sources for food webs in a number of isolated container systems, including discarded automobile tyres and tree holes. Containers are dominated by mosquitoes in the genera Culex and Aedes, which among other differences often engage in different foraging behaviours. We hypothesised that because Aedes feed more by browsing surfaces, whereas Culex often filter the water column, these mosquitoes would show variation in performance and differentially affect detritus. Effects of different ratios of animal and plant detritus on survival, mass, and development time for two common container mosquito species, Culex restuans L. and Aedes albopictus Skuse, were examined. We also quantified detrital contribution to biomass via isotopic and nutrient analysis and the effect of larvae on detrital decay. 2. Adult male and female mass of both species was highest with some animal detritus and lowest in only leaf detritus. Aedes albopictus survival was higher than C. restuans across most detritus ratios. 3. Aedes albopictus had higher values of ¹⁵N and in some cases ¹³C across all detritus ratios compared with C. restuans; A. albopictus had lower nitrogen in tissue. Aedes albopictus appeared to be more efficient at obtaining potentially limiting nutrients and had a greater overall effect on detrital decay – a possible consequence of greater foraging effort. 4. Findings further support the view that mosquito performance can be influenced by detritus type, and provide a more precise hypothesis (i.e. lower need for nitrogen) that may explain the superior competitive ability of A. albopictus over other container mosquitoes.     

Successional mosquito dynamics in surrogate treehole and ground‐container habitats in the northeastern United States: Where does Aedes albopictus fit in?

This study assessed the risk of larval displacement of the eastern treehole mosquito, Aedes triseriatus, and the northern house mosquito, Culex pipiens, by Aedes albopictus, the Asian tiger mosquito, during the establishment and successional stages of novel larval mosquito treehole and ground‐container habitats in the state of New Jersey, U.S.A. Culex pipiens and Culex restuans were the first mosquito species to colonize ground‐container habitats and were the dominant larval species throughout the study period, whereas Ae. albopictus was late to colonize ground habitats and accounted for less than 15% of weekly larval collections once established. Ae. albopictus had a much stronger community presence within treehole ovitraps; however, Ae. albopictus never reached the average larval densities of the expected primary colonizer, Ae. triseriatus. Throughout the study period, the weekly abundances of Ae. triseriatus and Ae. albopictus were positively correlated and there were no significant differences between the abundances of each species. The larval dominance of Ae. triseriatus appears to be enhanced by the presence of Toxorhynchites rutilus septentrionalis, a large predatory mosquito species. When Tx. rut. septentrionalis was present, mature larvae (3^rd–4^th instar) of Ae. albopictus were also present in only 16.7% of collections, whereas mature larvae of Ae. triseriatus were collected concurrently with Tx. rut. septentrionalis in 53.8% of collections. These data suggest that Ae. triseriatus is at a greater risk of displacement by Ae. albopictus than are Cx. pipiens and Cx. restuans.     

Blood‐feeding ecology of mosquitoes in zoos

To determine if the unique host assemblages in zoos influence blood‐feeding by mosquitoes (Diptera: Culicidae), a sampling programme was conducted in Greenville and Riverbanks Zoos, South Carolina, U.S.A., from April 2009 to October 2010. A total of 4355 female mosquitoes of 14 species were collected, of which 106 individuals of nine species were blood‐fed. The most common taxa were Aedes albopictus (Skuse), Aedes triseriatus (Say), Anopheles punctipennis (Say), Culex erraticus (Dyar & Knab), Culex pipiens complex (L.) and Culex restuans (Theobald). Molecular analyses (cytochrome b) of bloodmeals revealed that mosquitoes fed on captive animals, humans and wildlife, and took mixed bloodmeals. Host species included one amphibian, 16 birds, 10 mammals (including humans) and two reptiles. Minimum dispersal distances after feeding on captive hosts ranged from 15.5 m to 327.0 m. Mosquito–host associations generally conformed to previous accounts, indicating that mosquito behaviour inside zoos reflects that outside zoos. However, novel variation in host use, including new, exotic host records, warrants further investigation. Zoos, thus, can be used as experiment environments in which to study mosquito behaviour, and the findings extrapolated to non‐zoo areas, while providing medical and veterinary benefits to zoo animals, employees and patrons.     

The rise of the invasives and decline of the natives: insights revealed from adult populations of container-inhabiting Aedes mosquitoes (Diptera: Culicidae) in temperate North America

Container-inhabiting Aedes mosquitoes are successful invaders and important arthropod-borne disease vectors worldwide. In North America, a subtropical assemblage containing introduced Aedes albopictus and Aedes aegypti and the native Aedes triseriatus have served as a model for investigating ecological interactions during invasions and focused on the outcomes at the larval stages. We report a hypothesis driven study of a more temperate container Aedes assemblage at the adult population level monitored in the state of New Jersey during a 9-year period. The invasive A. albopictus and Aedes japonicus abundances increased by a factor of two, whereas A. triseriatus abundance decreased by a factor of three. Spatiotemporal analysis indicated these trends were coincident especially in the areas invaded by A. albopictus, leading to partial displacement of A. triseriatus. Although the invasive species reached peak abundance in highly urbanized areas, the native species’ rate of decline was similar across the urbanization gradient. Higher winter temperatures and precipitation favored increased A. albopictus abundance suppressing A. triseriatus adult populations in turn, whereas A. japonicus abundance was promoted by summer precipitation. The results validate the conceptual framework developed for subtropical container Aedes and suggest that the current climatic trends will favor further spread of A. albopictus, amplifying public health concerns.     

Diversity and seasonal abundances of mosquitoes at potential arboviral transmission sites in two different climate zones in Switzerland

Pathogens of medical or veterinary significance that are transmitted by mosquitoes (Diptera: Culicidae) are (re‐)emerging in Europe [e.g. West Nile virus (WNV), Dirofilaria nematodes]. Little is known about the spatiotemporal abundances of mosquito species in Switzerland. Therefore, mosquito population dynamics were investigated, focusing on areas of risk for sylvatic or synanthropic transmission, such as natural sites and suburban sites on either side of the Alpine crest. Repeated collections were made using Centers for Disease Control (CDC) traps, juvenile sampling and ovitrapping. A total of 122 831 mosquito specimens of 21 taxa were identified. Levels of mosquito species richness were similar at suburban sites and in natural zones in Switzerland. Mosquito abundances and seasonality were analysed with generalized linear mixed models based on 382 CDC trap samples (29 454 females) and revealed Aedes annulipes/cantans, Aedes geniculatus, Aedes japonicus, Aedes sticticus, Aedes vexans, Coquillettidia richiardii and Culex pipiens/torrentium as the dominant species overall. Abundances of these species were season‐dependent in most cases. There was an effect of site with regard to abundance (higher in natural zones), but not with respect to seasonality. Together with data on vector competence and the host preferences of different species, the present data contribute to assessments of risk for pathogen transmission. For example, both natural and suburban environments seem feasible as sites for amplification cycles of WNV and transmission to mammals.     

The mosquitoes of eastern Tennessee: studies on abundance,habitat preferences,and host‐seeking behaviors

A significant increase in the number of reported cases of La Crosse virus (LACV) infections in eastern Tennessee has occurred in the last ten years. The objective of this study was to determine the abundance and habitat preferences of the potential vectors of LACV in this region. Adult host‐seeking mosquitoes were collected using CO₂‐baited CDC light traps and a series of human‐landing catches in eastern Tennessee from 2004 to 2006. A total of 4,200 female mosquitoes of 23 species was collected by CO₂‐baited CDC trapping at ten sites during the study period. Aedes albopictus (Skuse) was the most abundant mosquito collected at all sites and vegetation types, with the ratios of total Ae. albopictus to Ae. triseriatus (Say) females collected being 2.1:1 in 2004, 3.8:1 in 2005, and 4.9:1 in 2006. Ten species were collected during a series of human‐landing catches made at four different sites; one probable and three confirmed case sites of LACV infections, totaling 528 female mosquitoes. Aedes albopictus was the most abundant species collected, with a 4:1 ratio of Ae. albopictus to Ae. triseriatus females. Aedes albopictus exhibited two clear peaks of “landing” activity, one in the early morning and one in the late afternoon or early evening. Simple and multiple regression analyses of the predictors of the number of mosquitoes collected showed that populations of Ae. albopictus were three times more likely to be collected overall than Ae. triseriatus. Species (Ae. albopictus), vegetation (residential), and the previous cumulative precipitation for the four weeks prior to collection were significantly (P < 0.05) associated with the number of mosquitoes collected by CO₂‐baited CDC trapping. Aedes albopictus was also more likely to be collected than Ae. triseriatus at confirmed cases of LACV infections.     

Understanding the mechanism of Chikungunya virus vector competence in three species of mosquitoes

Chikungunya virus (CHIKV) is primarily transmitted by Aedes spp. mosquitoes. The present study investigated vector competence for CHIKV in Aedes aegypti and Aedes albopictus mosquitoes found in Madurai, South India. The role of receptor proteins on midguts contributing to permissiveness of CHIKV to Aedes spp. mosquitoes was also undertaken. Mosquitoes were orally infected with CHIKV DRDE‐06. Infection of midguts and dissemination to heads was confirmed by immunofluorescence assay at different time points. A plaque assay was performed from mosquito homogenates at different time points to study CHIKV replication. Presence of putative CHIKV receptor proteins on mosquito midgut epithelial cells was detected by virus overlay protein binding assay (VOPBA). The identity of these proteins was established using mass spectrometry. CHIKV infection of Ae. aegypti and Ae. albopictus midguts and dissemination to heads was observed to be similar. A plaque assay performed with infected mosquito homogenates revealed that CHIKV replication dynamics was similar in Aedes sp. mosquitoes until 28 days post infection. VOPBA performed with mosquito midgut membrane proteins revealed that prohibitin could serve as a putative CHIKV receptor on Aedes mosquito midguts, whereas an absence of CHIKV binding protein/s on Culex quinquefasciatus midguts can partially explain the non‐permissiveness of these mosquitoes to infection.     

Aedes albopictus oviposits with other Aedes species in artificial oviposition cups: a case study in Knox County,Tennessee, U.S.A.

Interspecific associations between two mosquito species can lead to effects such as competition, species displacement, and species stability. To better understand Aedes albopictus (Skuse) and other Aedes species, we monitored eggs in artificial oviposition cups (ovitraps) within Knox County, TN, U.S.A., during the 2016 and 2017 mosquito seasons. In 2016, one black and one white ovitrap were placed at 18 sites for 21 weeks, while in 2017 black and white ovitraps baited with grass‐infused or deionized water were placed at 11 sites for nine weeks. Eggs were identified to species and resulting counts were used to determine the degree of interspecific association using Cole's coefficients (C₇) and the degree of heterogeneity across space and time using generalized linear mixed models (GLMM). Here, Aedes mosquitoes are generally ovipositing in black cups with grass‐infused water, and Ae. albopictus eggs co‐occurred with other Aedes species more often than would be expected. Finding a positive significant interspecific association between Ae. albopictus and other Aedes eggs suggests that methods used to control Ae. albopictus may also control other Aedes mosquitoes. Finding that Ae. albopictus co‐occurs with other Aedes mosquitoes warrants additional research to evaluate outcomes associated with co‐occurrence within the study area.     

Updated checklist of the mosquitoes (Diptera: Culicidae) of Croatia

Improvement of morphological and molecular identification methods allows the detection of new species of mosquitoes. The mosquito fauna of Croatia currently includes 52 species, belonging to eight genera, including Anopheles (12 species), Aedes (24 species), Coquillettidia (one species), Culex (seven species), Culiseta (six species), Orthopodomyia (one species), and Uranotaenia (one species). This is an updated checklist, which includes five new species found in Croatian mosquito fauna. Two of these are invasive mosquito species, Aedes albopictus (Skuse, 1895) and Aedes japonicus (Theobald 1901), which are spreading across Europe and Croatia. The other three species, Culex laticinctus (Edwards 1913), Culex torrentium (Martini 1925), and Anopheles daciae (Linton, Nicolescu & Harbach 2004) are autochthonous species which haven't been recorded so far. Since there are several more invasive species spreading across Europe, we assume that this is not the final list.     

The composition,diversity, and distribution of mosquito fauna (Diptera: Culicidae) in Kosovo

The aim of this study is to identify the mosquito species that currently exist and their distributions in Kosovo in order to determine current potential endemic zones and areas at a higher risk for future epidemics. These scientific data will be shared with public health authorities for implementing mosquito control programs. During a two‐year period of monitoring in 48 localities in 23 provinces in Kosovo, a total of 1,604 mosquitoes representing 13 species and six genera were collected and morphologically identified. Members of species complexes were also classified to species using DNA barcoding. In total, 13 species were identified with Culex pipiens s.l., the predominant species with an abundance rate of 39%. The remaining 12 species identified were grouped into five genera: Anopheles, Aedes, Coquillettidia, Culiseta, Uranotaenia, including species that are vectors of arboviruses in other parts of the world.     

Pest occurrence of Aedes rossicus close to the Arctic Circle in northern Sweden

Major nuisance species are found among the floodwater mosquitoes and snow‐pool mosquitoes, with the former being the main reason for mosquito control in most areas. Nuisance species vary with the area, and previous reports from northern areas conclude that the nuisance is most often caused by snow‐pool mosquitoes. We investigated the mosquito fauna and abundances of host‐seeking females using CDC traps baited with carbon dioxide, in Övertorneå city near the Arctic Circle in northern Sweden, after earlier complaints about massive mosquito nuisance. The abundance of host‐seeking female mosquitoes was high in 2014, with a maximum of ～15,400 individuals per CDC trap night, of which 89% was the floodwater mosquito Aedes rossicus. Surprisingly, the main nuisance species was a floodwater mosquito, occurring at the northernmost location it has ever been recorded in Sweden. Our report is probably the first documentation of such large numbers of Aedes rossicus in any locality and probably the first documentation of a severe floodwater mosquito nuisance near the Arctic Circle. Given the historical data on river discharge in the area, the nuisance is recurrent. We conclude that in northern localities, as well as in more southern localities, production of floodwater mosquitoes is a natural component of the floodplain fauna of rivers with a fluctuating water flow regime. Also, the floodwater mosquitoes Aedes sticticus and Aedes vexans were found north of their formerly known distribution in Sweden.     

Influence of competing and predatory invertebrate taxa on larval populations of mosquitoes in temporary ponds of wetland areas in Germany

Abundances of mosquito larvae and associated invertebrate communities were assessed in 27 temporary ponds during the spring season in wetland areas of Germany. Four genera of mosquitoes were identified: Aedes, Anopheles, Culex, and Culiseta. We focused our analyses on Aedes spp. because this genus was the most abundant (92% of total abundance) and frequently encountered mosquito (present in 65% of investigated sites). The abundance of Aedes spp. was negatively associated with the abundance of competitors for food, and to a lesser extent with those of intraguild predators and strict predators. The influence of these natural antagonists on larvae of Aedes was stronger in ponds with higher levels of dissolved oxygen (53 ± 4%) than in ponds with lower levels (16 ± 1%). The overall abundance of antagonists explained 42% of the variation in abundance of Aedes spp. at sites with higher levels of dissolved oxygen. Of this explained variation, competitors accounted for 34.7%, whereas the abundance of intraguild predators and strict predators accounted for only 6.8 and 0.5%, respectively. Therefore, the promotion of competing species might be an appropriate ecological approach for the control of Aedes spp. in temporary ponds in these areas.     

Laboratory Evaluation of Controlled-release Repellent Treated Pulp Fabric on Human Volunteers Against Mosquito Vectors

Three controlled‐release personal‐use pulp fabric impregnated insect repellent formulations of 5% N, N‐diethyl‐3‐methylbenzamide (DEET), and 10% and 15% neem oils were evaluated in an environmental chamber on volunteers for their repellent efficacy against three mosquito species, Culex pipiens pallens, Aedes aegypti and Ochlerotatus togoi. The 5% DEET formulation showed significant repellency in pulp fabric (5 mm in width) against Culex pipiens pallens and Aedes aegypti (P < 0.05), providing an average repellency of 88.0%, 66.3%, and 46.8% of Cx. pipiens pallens, Ae. Aegypti and O. togoi bites, respectively, during the 6 hours of exposure period. Against night‐biting mosquitoes Cx. pipiens pallens, the DEET formulation provided mostly complete protection for at least 4 hours after the application. In pulp fabric of 10 mm in width, the 5% deet formulation showed significantly the highest repellency among the repellents against O. togoi (P<0.05), providing an average repellency of 52.3% during the 6 hours of exposure period. However, the pulp fabrics treated with 10% and 15% neem oil were less effective than 5% DEET against three mosquito species. This study demonstrated the potential of 5% DEET as pulp fabric repellent against both day‐ and night‐biting mosquitoes.     

Invasive Process and Repeated Cross-Sectional Surveys of the Mosquito Aedes japonicus japonicus Establishment in Belgium

When accidentally introduced in a new location, a species does not necessarily readily become invasive, but it usually needs several years to adapt to its new environment. In 2009, a national mosquito survey (MODIRISK) reported the introduction and possible establishment of an invasive mosquito species, Aedes j. japonicus, in Belgium. First collected in 2002 in the village of Natoye from a second-hand tire company, then sampled in 2003 and 2004, the presence of adults and larvae was confirmed in 2007 and 2008. A repeated cross-sectional survey of Ae. j. japonicus was then conducted in 2009 in Natoye to study the phenology of the species on two different sites using three kinds of traps: Mosquito Magnet Liberty Plus traps, BG sentinel traps and CDC Gravid traps. An analysis of the blood meals was done on females to assess the epidemiological risks. Five species of mosquitos were caught using the different kind of traps: Culex pipiens, Cx torrentium, Anopheles claviger, Aedes geniculatus and Ae. j. japonicus, Cx pipiens being the most abundant. The CDC gravid traps gave the best results. Surprisingly Ae. j. japonicus was only found on one site although both sites seem similar and are only distant of 2.5 km. Its population peak was reached in July. Most of the engorged mosquitoes tested acquired blood meals from humans (60%). No avian blood meals were unambiguously identified. Larvae were also collected, mostly from tires but also from buckets and from one tree hole. Only one larva was found in a puddle at 100 m of the tire storage. A first local treatment of Ae. j. japonicus larvae population was done in May 2012 using Bacillus thuringiensis subsp. israelensis (Bti) and was followed by preventive actions and public information. A monitoring is also presently implemented.     

Predation differentially structures immature mosquito populations in stormwater ponds

1. Understanding the factors underlying the abundance and distribution of species requires the consideration of a complex suite of interacting biotic and abiotic factors operating on multiple spatial and temporal scales. Larval mosquitoes inhabiting small human-constructed ponds represent a unique opportunity to investigate the relative importance of these structuring mechanisms while simultaneously generating applied knowledge on mosquito control. 2. A multi-year field survey of 32 stormwater ponds was conducted in central Illinois (Champaign County). From each pond, data were collected on pond structure type and hydroperiod, the presence/absence of cattails (Typha spp.), and measures of total nitrogen, phosphorus, and organic carbon, and chlorophyll a. The communities of crustacean zooplankton and aquatic insects were characterised, and these taxa were assigned into two main groups: predators and competitors of larval mosquitoes. Structural equation modelling was used to explore the direct and indirect effects of these biotic and abiotic factors on larval density for three species of culicine mosquitoes (Culex pipiens, Culex restuans, and Aedes vexans). 3. Hydroperiod had an indirect negative effect on C. pipiens density. However, this effect was mediated by predator density; more permanent ponds had more predators, which therefore reduced the density of C. pipiens larvae. Aedes vexans density was positively correlated with predator density. No predictor variables were found that explained variation in C. restuans density. 4. This study show that the relative importance of these biotic and abiotic factors varies among species of culicine mosquitoes inhabiting stormwater ponds.