Quinquefasciatus Say Research Articles

Predominância de Culex quinquefasciatus durante a vigilância integrada de mosquitos em uma área urbana da Amazônia brasileira

The presence and establishment of Culicidae in urban areas increase the transmissibility of tropical diseases, since some species can participate as vectors of pathogens. Thus, this study aimed to evaluate the indoor and outdoor abundance of immature and adult populations of Culicidae at the urban area of Porto Velho, Rondônia. Mosquitoes were captured using electric aspirators and ovitraps in September and December 2018 in 27 households spread over nine neighborhoods. A total of 2,342 specimens were collected, distributed among five species, of which Culex quinquefasciatus (Say, 1823), Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1894) were the most abundant. Considering the sum total obtained by both techniques, more mosquitoes were captured indoors than outdoors. However, the GLM estimates for the ovitrap technique showed that immature Ae. aegypti, Ae. albopictus and Cx. quinquefasciatus were significantly more abundant in the outdoors, on average. The opposite result was observed for electrical aspiration, in which Ae. aegypti and Cx. quinquefasciatus adults were more abundant indoors. The average number of winged Ae. albopictus showed no significant difference between indoors and outdoors. Our findings corroborate the data on the abundance and incidence of these three species in other regions of Brazil, highlighting the need for continuous surveillance due to their importance in disease transmission to humans. We also demonstrated that the ovitrap is a sensitive device to monitor Cx. quinquefasciatus larvae and wild species that occasionally frequent urban areas, and thus can be used for surveillance, especially when there are budgetary constraints. Therefore, we emphasize that the combination of techniques, in addition to identifying which species and which stage of development are more frequent inside and outside households, also allows for the implementation of specific and integrated control measures.

Evaluation of antioxidant and larvicidal activities of selected tamarix species against the southern house mosquito “Culex quinquefasciatus (Say)”

Evaluation of antioxidant and larvicidal activities of selected tamarix species against the southern house mosquito “Culex quinquefasciatus (Say)”

A Comparison of Hay and Fish Emulsion-Infused Water as Oviposition Attractants for the CDC Gravid Trap.

Multiple oviposition attractants are used for Culex (Diptera: Culicidae) mosquito surveillance in the CDC Gravid Trap, including hay and fish emulsion-infused water. Despite the use of both in the United States, no research has compared their attractiveness. We conducted trapping throughout Louisiana to assess the attractiveness of hay and fish emulsion-infused water in various habitat types and climates. Our results indicate that fish emulsion-infused water attracts more mosquitoes overall, more Culex quinquefasciatus (Say, 1823), and a wider diversity of mosquitoes than hay-infused water. This trend was maintained, regardless of habitat type or climate.

Genome analysis of Lysinibacillus sphaericus isolate 6.2 pathogenic to Culex quinquefasciatus Say, 1823 (Diptera: Culicidae)

Abstract. Viersanova A, Purwanto H. 2021. Genome analysis of Lysinibacillus sphaericus isolate 6.2 pathogenic to Culex quinquefasciatus Say, 1823 (Diptera: Culicidae). Biodiversitas 22: 5211-5222. Lysinibacillus sphaericus is an entomopathogenic bacteria that is specific to vector mosquitoes, especially Culex spp., and Anopheles spp., so it has been widely used as a bioinsecticide. L. sphaericus has a wide variation of toxicity efficiencies, which have led to continuous exploration of new isolates with higher toxicity and a new toxin to deal with resistance problems. This study aimed to identify the genomic characteristics and toxin characteristics of isolate 6.2 based on whole genome analysis and analyze the identification of isolate 6.2. Isolate 6.2 was previously obtained from rhizosphere in Yogyakarta. To analyze the genome and toxins, the NGS technique was used and then the analysis was carried out using a couple of freely available bioinformatics tools. Molecular identification was carried out with the 16SrRNA gene and the relationship was analyzed by reconstructing the phylogenetic tree using Neighbours-Joining. The genomic analysis of isolate 6.2 showed good results with G+C content and genome size that matched the reference genome of L. sphaericus. The result of the 16SrRNA gene blasting showed that the closest related gene of isolate 6.2 is L. fusiformis (NR_042072.1). However, the reconstructed phylogenetic tree did not show the formation of clusters according to the species. Toxin analysis indicates that isolate 6.2 has Mtx, s-layer protein, hemolysin, and chitin-binding protein genes. All of which are known to be associated with the toxicity of L. sphaericus to binary toxin resistant population of Culex quinquefasciatus.

SURVEY OF MOSQUITO SPECIES, COMPOSITION AND BREEDING HABITATS IN FOUR COMMUNITIES OF KADUNA METROPOLIS, NIGERIA

A survey on the species composition and breeding habitats of mosquitoes was conducted in four communities of Kaduna metropolis (Nariya, Tudun Wada, Kabala Doki and Sabon Tasha) through intensive bi-weekly sampling collection of larvae for a period of three months. All the randomly selected sampling points were categorized into three habitat types; Domestic Container (DC), Temporary Ground Pool (TGP) and Man-made Reservoir (MMR). All 3rd and 4th instar larvae were harvested and identified using taxonomic keys by Gillies and Coetzee. A total of 6,803 larvae samples were encountered and identified across the four communities. There were thirteen species which fall within the three common genera comprised of Culex species (94.19%), Aedes species (4.8%) and Anopheles (0.10%). Of the thirteen species identified, Culex quinquefasciatus Say, 1823 (72.8%) was significantly high (p<0.05), then Culex toroensis Edwards(12.05%) and Aedes aegypti Linnaeus (4.8%). Temporary ground pool (61.7%) harbored more mosquito larvae; however there was no significant difference (p>0.05) in distribution of mosquitoes among the three habitat types sampled; The study identified medically important mosquito species in the four communities and recommends integrated control measures for these vectors especially in line with National Malaria Control strategy 2016 - 2030 for global reduction of malaria disease

Avoidance Behavior to Guava Leaf Volatile Oil by Three Medically Important Mosquito Vectors.

Volatile organic compounds from various plants have received popular interest as one of the vector control tools due to their eco-friendliness and insect-repellent activities. In this study, an excito-repellency assay system was used to examine the noncontact repellency, contact excitation, and knockdown (KD) effects of guava leaf (Psidium guajava L.) oil against Anopheles minimus (Theobald), Anopheles epiroticus (Linton & Harbach), and Culex quinquefasciatus (Say). The organic components of guava oil were identified by gas chromatography-mass spectrometry analysis with dl-limonene (17.4%), cymene (5.49%), and α-terpinene (5.20%) as the major constituents. At concentrations of 2.5 and 5.0%, 100% escape of An. minimus was recorded in the contact assay and 96-98% escape in the noncontact assay. Guava oil stimulated potent irritant (92% escape) and repellent (61-86% escape) effects against Cx. quinquefasciatus. A lower repellency action was observed against An. epiroticus (17-20% escape). No KD effect was observed for guava oil against An. minimus and Cx. quinquefasciatus at any concentration. However, An. epiroticus was more prone to KD effects, with the highest percentage KD (44% in nonescape group) observed with 5.0% guava oil in the noncontact assay. Mortalities of 35% and 11% were observed for An. epiroticus in the nonescape groups in the contact and noncontact assays, respectively. Concentrations of 1.0% and 2.5% guava oil led to <2% mortality in An. minimus. Our findings highlight guava oil as a promising plant-based mosquito repellent that can be included in insecticide formulations for future mosquito control programs.

Bioactivity and safety evaluations of Cupressus sempervirens essential oil, its nanoemulsion and main terpenes against Culex quinquefasciatus Say.

The essential oil (EO) of Cupressus sempervirens was obtained by hydrodistillation and analysed using gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Two monoterpenes, α-pinene (49.1%) and δ-3-carene (21.4%), and one sesquiterpene hydrocarbon, α-cedrol (5.1%), were isolated as the EO major terpenes. An oil-in-water nanoemulsion (particle size 71.2 nm) was produced from the EO through a low-energy method. The EO, its nanoemulsion and its main constituents showed mosquitocidal and biochemical effects against Culex quinquefasciatus Say, the common vector of lymphatic filariasis parasites. All treatments showed dose-dependent bioactivity, and adults were more susceptible to the EO products than the larvae. The nanoemulsion showed superior activity, followed by the crude EO and α-cedrol. At 40 μg/ml, the nanoemulsion caused 100% larval mortality, while the EO and α-cedrol required twice this concentration to achieve the same larval mortality. The LC50 values were 8.4, 16.1, 15.1, 30.7 and 53.4 μg/ml at 24 h after exposure for the nanoemulsion, crude oil, α-cedrol, δ-3-carene and α-pinene, respectively. For adults, 20.0 μl/l nanoemulsion caused 100% mortality, while twice this concentration of the EO was required to achieve the same effect. The LC50's against adults ranged between 6.2 and 40.4 μl/l. EO products prominently repelled mosquitoes at concentrations between 0.75 and 6.0 μl/cm2. The EO products caused remarkable inhibition of Cx. quinquefasciatus acetylcholinesterase activity but were safer towards the non-target aquatic species Gambusia affinis. These results recommend the use of C. sempervirens EO, its nanoemulsion and main terpenes as natural tools to control Cx. quinquefasciatus.

Susceptibility of Culex quinquefasciatus (Say) Larvae to Methanolic Extracts of Annona reticulata.

&lt;b&gt;Background and Objective:&lt;/b&gt; Environment pollution and resistance of many pests to the most frequently used chemical insecticides gave the rationale of altering to replace them with natural herbal extracts for pests and vector control. This study investigated the effect of methanolic extract of &lt;i&gt;Annona reticulata&lt;/i&gt; on the mortality and development of larvae of &lt;i&gt;Culex quinquefasciatus&lt;/i&gt;. &lt;b&gt;Materials and Methods:&lt;/b&gt; Methanolic herbal extracts were analyzed using Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC) to identify the phytochemical compounds in them. Ten mosquito larvae were used as replicates and exposed to each of the five concentrations of the plant extract (30, 100, 150, 200 and 250 mg mL&lt;sup&gt;1&lt;/sup&gt;) and ten larvae were exposed to double distilled water and considered as control. &lt;b&gt;Results:&lt;/b&gt; Phytochemical analysis revealed the presence of phenols, steroids, quinones, tannins and saponins. Statistical analysis showed a significant strong correlation and regression between exposure to the different concentrations of the extract and mortality of &lt;i&gt;Culex quinquefasciatus&lt;/i&gt; larvae where R&lt;sup&gt;2&lt;/sup&gt; = 0.982, the Correlation value is 0.991099 (p<0.05). Results also showed that the extracts affect the development of larvae more than mortality. The effect of the extracts on the early larval stages was significantly high compared to the late stages of larvae. &lt;b&gt;Conclusion:&lt;/b&gt; According to our knowledge results of this study has been reported for the first time in Saudi Arabia where &lt;i&gt;Annona reticulata&lt;/i&gt; is neglected regionally and no study approved its efficacy as a botanical herbal extract against mosquitoes.

Mosquito species associated with horses in Madagascar: a review of their vector status with regard to the epidemiology of West Nile fever.

In Madagascar, the high West Nile virus (WNV) antibody prevalence reported in horse populations suggests a high level of vector-horse contact. This study aims to characterize the mosquito species usually involved in WNV transmission in horse stables in Madagascar. Five horse stables were investigated in October and November 2016 in five distinct inland areas. Mosquitoes were collected using double net traps baited with human, poultry or horse as well as light traps. Blood meal identification from engorged females was performed using host-specific PCRs. A total of 2898 adult mosquitoes were collected with Culex (Culex) antennatus (Becker) (40.7%), and Cx. (Cux.) quinquefasciatus Say (14.9%), being the most abundant species. The mosquito abundance varied between horse stables (P < 10-7 ) and depending on the bait used in the double net traps (P < 0.003). Among the 190 tested blood meals, 119 consisted of single blood meals with 85 from horse, 17 from human, 16 from chicken, one from cattle and 71 consisted of mixed blood meals. The mosquito species collected during this study exhibited a generalist feeding behaviour allowing them to act as bridge vectors between different vertebrate hosts involved in WNV transmission cycle. Their vector status with regard to West Nile fever epidemiology is reviewed.

Tiger nut (Cyperus esculentus) as a potential phytoinsecticide: larvicidal activity of crude extracts on Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae).

Plants contain bioactive compounds and are constantly explored as safer alternatives to conventional insecticides. Despite numerous studies on many plants, information on the insecticidal potential of underutilised plants like tiger nut, Cyperus esculentus L., are scant, although their pharmacological potentials are well known. Hence, this study investigated the larvicidal potential of crude aqueous extracts of two C. esculentus varieties (black and yellow) on the mosquitoes Aedes aegypti (L.) and Culex quinquefasciatus (Say). Mosquito larvae were exposed to C. esculentus crude extracts using the larval bioassay technique of the World Health Organization. Differential larvicidal responses were observed in the test mosquitoes and extracts of Black Dried Tiger nuts (BDT) were more larvicidal than Yellow Dried Tiger nuts (YDT). Acute larval toxicity of the extracts was more pronounced on Cx. quinquefasciatus than Ae. aegypti. The results indicate the potential of C. esculentus (particularly BDT) as a source of mosquito bioinsecticide and merits further studies as a safer alternative to conventional insecticide-based vector control.

Olfactory responsiveness of Culex quinquefasciatus and Aedes albopictus (Diptera: Culicidae): Interactions between species, age and attractants

Invasive mosquitoes are vectors of important human and animal pathogens and a serious threat to public health. Aedes albopictus (Skuse) (Diptera: Culicidae) and Culex quinquefasciatus (Say) (Diptera: Culicidae) are good examples because of their wide occurrence, host range and vector competence. An understanding of the responsiveness of mosquitoes to olfactory stimuli is essential for implementing effective surveillance and developing repellents. The present study evaluated the behavioural responses of A. albopictus and C. quinquefasciatus to CO2 and human skin odour in an olfactometer. In addition, CO2 synergistic effect was assessed in association with human skin odour. Mosquitoes of different ages (3-5 and 10-15 day old) were included in the study in order to determine changes in responsiveness to attractants during an insects' lifetime. The highest numbers of mosquitoes captured associated with CO2 were (A. albopictus, 48/77, 62.34%; C. quinquefasciatus, 117/126, 92.86%) and hand odour (A. albopictus, 211/232, 90.95%; C. quinquefasciatus, 320/374, 85.56%) in the "CO2 vs blank" and "hand vs blank" treatments. Skin odour was the most attractive for both species (A. albopictus, 279/309, 90.29%; C. quinquefasciatus, 292/306, 95.42%) in "CO2 vs hand" experiment. The highest mosquito responsiveness was recorded in the "CO2 + hand vs hand" bioassay (A. albopictus, 174/265, 65.66%; C. quinquefasciatus, 231/425, 54.35%). Similar trends were recorded for 10-15 and 3-5 day old mosquitoes of both species in all the experiments. In addition, a linear mixed model was used to evaluate the interactions between species, age and attractants. Human skin odour and CO2 were effective attractants for both A. albopictus and C. quinquefasciatus (attractant-species interaction, p-value &lt; 0.05). CO2 synergistic effect was recorded for both species (species-attractant interaction, p-value &lt; 0.05) even when CO2 was not directly combined with skin odour (p-value &lt; 0.05). The interaction between attractant and age revealed (p-value &lt; 0.05) that in both species, 10-15 day old mosquitoes were more responsive to CO2 and human skin odour, than younger (3-5 days) adults. The species-age interaction (p-value &lt; 0.05) showed that 3-5 and 10-15 day old C. quinquefasciatus were more receptive to CO2 and skin odour, especially when used in combination, than A. albopictus.

EVALUATION OF ORANGE OIL APPLIED BY THREE BACKPACK SPRAYERS AGAINST AEDES AEGYPTI AND CULEX QUINQUEFASCIATUS

A solvent orange oil has been used to mix with permethrin and PBO as a commercial adulticide product called Aqualure® 20-20 for control of adult mosquitoes. The orange oil at 2.7% and 3.5% sprayed by three backpack sprayers, Hudson battery operated sprayer modified with a Solo nozzle, hand pump sprayer Solo-425, and Birchmeire battery operated sprayer, against caged adult female Aedes aegypti Linn. and Culex quinquefasciatus Say resulted in 89%–100% mortality of Ae. aegypti and 100% mortality of Cx. quinquefasciatus. The three different backpack sprayers did not show any significant differences in the percent mortality. Our test results demonstrate that orange oil alone at a high dose (3.5 %) showed effective insecticidal characteristics against both species of adult mosquitoes.

Culex quinquefasciatus (Diptera: Culicidae) survivorship following the ingestion of bird blood infected with Haemoproteus sp. parasites

Arthropod vectors are frequently exposed to a diverse assemblage of parasites, but the consequence of these infections on their biology and behavior are poorly understood. We experimentally evaluated whether the ingestion of a common protozoan parasite of avian hosts (Haemoproteus spp.; Haemosporida: Haemoproteidae) impacted the survivorship of Culex quinquefasciatus (Say) (Diptera: Culicidae). Blood was collected from wild northern cardinals (Cardinalis cardinalis) in College Station, Texas, and screened for the presence of Haemoproteus spp. parasites using microscopic and molecular methods. Experimental groups of Cx. quinquefasciatus mosquitoes were offered Haemoproteus-positive cardinal blood through an artificial feeding apparatus, while control groups received Haemoproteus-negative cardinal blood or domestic canary (Serinus canaria domestica) blood. Culex quinquefasciatus mosquitoes exposed to Haemoproteus infected cardinal blood survived significantly fewer days than mosquitoes that ingested Haemoproteus-negative cardinal blood. The survival of mosquitoes fed on positive cardinal blood had a median survival time of 18 days post-exposure and the survival of mosquitoes fed on negative cardinal blood exceeded 50% across the 30 day observation period. Additionally, mosquitoes that fed on canary controls survived significantly fewer days than cardinal negative controls, with canary control mosquitoes having a median survival time of 17 days. This study further supports prior observations that Haemoproteus parasites can be pathogenic to bird-biting mosquitoes, and suggests that Haemoproteus parasites may indirectly suppress the transmission of co-circulating vector-borne pathogens by modulating vector survivorship. Our results also suggest that even in the absence of parasite infection, bloodmeals from different bird species can influence mosquito survivorship.

Larvicidal and ovicidal activities of phenyl acetic acid isolated from Streptomyces collinus against Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidae)

The bio-efficacy of crude ethyl acetate extract, fractions and a compound phenyl acetic acid from the ethyl acetate extract of Streptomyces collinus was evaluated on Culex quinquefasciatus Say and Aedes aegypti L. mosquitoes (Diptera: Culicidae). The larvae were exposed to concentrations of 2.5, 5.0, 7.5 and 10.0 ppm for fractions and 0.5, 1.0, 1.5 and 2.0 ppm for compound. After 24 h, the larval mortality was assessed and the LC₅₀ and LC90 values were calculated. Similarly, per cent ovicidal activity was calculated for eggs after 120 h post treatment for phenyl acetic acid. Among the eleven fractions screened, fraction 7 from the ethyl acetate extract of Streptomyces collinus exhibited good larvicidal activity against both mosquito species. The LC50 and LC90 values of fraction 7 were 4.42, 6.23 ppm against Cx. quinquefasciatus larvae and 5.13, 14.51 ppm against Ae. aegypti larvae, respectively. Further, the isolated compound, phenyl acetic acid from fraction 7 recorded 100% larvicidal activity at 2 ppm concentration with LC50 and LC90 values of 2.07, 4.87 ppm on Cx. quinquefasciatus larvae and 3.81, 9.87 ppm on Ae. aegypti larvae, respectively. Phenyl acetic acid presented 50.3% and 42.0% ovicidal activity against Cx. quinquefasciatus and Ae. aegypti eggs at 2 ppm concentration after 120 h post treatment. The compound, phenyl acetic acid could be used in mosquito control programme.

Efficacy of Some Selected Indigenous Plant Extracts against Two Urban Mosquitoes Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidea): An Update

Efficacies of the chloroform and aqueous extracts of the leaf, stem and root of three indigenous plants viz. Calotropis procera, Polygonum hydropiper and Thevetia neriifolia against the larval mortality and reproductive potential of two urban mosquitoes Culex quinquefasciatus Say and Aedes aegypti L. are reported here. Results show that the chloroform extracts of C. procera leaf (LC50 = 167.48 ppm), P. hydropiper stem (LC50 = 341.79 ppm) and T. neriifolia leaf (LC50 = 209.45 ppm) had excellent larvicidal effect on Cx. quinquefasciatus. The aqueous extracts of C. procera stem (LC50 = 207.18 ppm), P. hydropiper stem (LC50 = 634.92 ppm) and T. neriifolia leaf (LC50 = 453.34 ppm), however, had relatively milder larvicidal effect on the mosquitoes under study. Both the extracts significantly reduced percentage of egg-hatch and adult emergence per raft, lengthened immature duration and increased immature mortality in all the treatment groups. The chloroform extracts had a significantly negative effect on the number of eggs per raft, but both chloroform and aqueous extracts failed to induce any appreciable effect on the female ratio. Compared to the aqueous extracts, chloroform extracts are much more efficient against Cx. quinquefasciatus productivity. Results on Ae. aegypti indicated that the leaf extracts of C. procera (LC50 =696.14 ppm), the stem extract of P. hydropiper (LC50 =1164.36 ppm), and the leaf extract of T. neriifolia (LC50 =872.91 ppm) had significant larvicidal effects compared to the respective controls. In general, the extracts significantly reduced egg-laying, decreased egg-hatch, lengthened immature duration, and increased immature mortality culminating in reduced adult emergence. A comparison of the larvicidal efficacy of the extracts against the two mosquito species reveals that Cx. quinquefasciatus is more sensitive to the plant extracts than Ae. aegypti. However, further research is solicited to evaluate the impact, persistence and effectiveness of these extracts against the vector mosquitoes under indoor and field conditions.

Culex/ mosquitoes (Diptera: Culicidae) recorded along the Nile River in central and northern Sudan, with a key for the identification of all species of the genus known to occur in the country.

Despite the importance of Culex species as major vectors of Rift Valley fever virus, West Nile virus and the microfilariae that cause lymphatic filariasis, information on these mosquitoes in Sudan is limited to works published 65 years ago in the former Anglo-Egyptian Sudan, where some species were only recorded from areas of the territory now known as South Sudan. In this paper, we provide updated information on Culex mosquitoes collected indoors during surveillance studies conducted along the Nile River in central and northern areas of Sudan between 2012 and 2019. Of 3,411 female mosquitoes collected in Khartoum and northern states along the river, 2,560 (75%) were specimens of Culex belonging to 12 species: Cx. (Culex) antennatus (Becker, 1903), Cx. (Cux.) laticinctus Edwards, 1913, Cx. (Cux.) neavei Theobald, 1906, Cx. (Cux.) pipiens Linnaeus, 1758, Cx. (Cux.) perexiguus Theobald, 1903, Cx. (Cux.) poicilipes (Theobald, 1903), Cx. (Cux.) quinquefasciatus Say, 1823, Cx. (Cux.) simpsoni Theobald, 1905, Cx. (Cux.) sinaiticus Kirkpatrick, 1925, Cx. (Cux.) theileri Theobald, 1903, Cx. (Cux.) tritaeniorhynchus Giles, 1901 and Cx. (Culiciomyia) macfiei Edwards, 1923. This is the first record for Cx. tritaeniorhynchus and Cx. macfiei in central Sudan. The relative abundance of each species varied in different areas and seasons, but Cx. antennatus and Cx. quinquefasciatus were the most abundant indoor resting species. We provide an updated dichotomous key for the identification of the adults of Culex mosquitoes known to occur in the Republic of the Sudan.

Dose-Response Assay for Synthetic Mosquito (Diptera: Culicidae) Attractant Using a High-Throughput Screening System.

Simple SummaryEntomological surveillance is important to evaluate vector management interventions. However, collecting adult mosquitoes using direct human bait is controversial and often discouraged because of potential infection risk. Alternatively, active and passive trapping methods are available. Female mosquitoes detect human host cues such as body heat, carbon dioxide, and other volatile body emanations using olfactory sensilla to direct movement to a host. Attractive chemical lures have been identified and evaluated using a variety of olfactometric methods to increase trap production and efficiency. In this study, we evaluated a simple olfactometer without need of airflow. To ‘optimize’ a commercial mosquito attractant, 10 different doses of product, the Biogents-lure (BG-lureTM), were compared. Results showed dose-dependent responses with 0.005 g with the highest attraction for Aedes aegypti, while doses of 0.2 g and above produced a repellent response. There was no significantly different response behavior between permethrin-susceptible and -resistant Ae. aegypti. Culex quinquefasciatus showed significantly different responses compared to Ae. aegypti by producing attraction over four times a wider range of amounts. These results demonstrate a simple olfactometer device to screen potential chemical attractants without use of an air-plume, thus expanding testing capabilities beyond more sophisticated laboratory settings.Natural volatile host cues play a critical role for mosquito orientation and locating a blood source for egg production. Similar olfactory activation responses have allowed the use and development of artificial chemical attractants to lure mosquitoes to trapping devices. Using a pre-formulated commercial product mixture of different attractant chemicals, a high-throughput screening system (HITSS) is used to screen varying doses of chemical required to activate behavioral responses. Two strains of Aedes aegypti (L.): permethrin-susceptible (USDA) and -resistant (Pu Teuy) phenotypes and one Culex quinquefasciatus Say. (NIH) laboratory strain were tested. Overall, mosquitoes showed repellency between 1.0 g and to 10.0 g dose of each compound. However, by progressively reducing the dose, Cx. quinquefasciatus showed a greater positive percent attraction (88.9%) at 0.025 g, whereas the USDA and Pu Teuy Ae. aegypti produced optimum attractant activation at 0.005 g (72.6% and 58.9%, respectively) without significant difference within species (p > 0.05). In parallel control assays, Cx. quinquefasciatus was significantly attracted to 1 g of dry ice (carbon dioxide) (76%) more than Ae. aegypti (USDA) (12.2%). The HITSS was originally designed to measure three chemical actions to sublethal concentrations of chemicals by mosquitoes: toxicity and the two primary behavior avoidance responses (contact excitation and spatial repellency). These findings demonstrate that the HITSS assay, with only minor modifications, allows comparison screening of candidate compounds as potential attractants for anemotactic responses under laboratory-controlled conditions. Further investigations will be required to equate measurements obtained from controlled laboratory assays to more varied field conditions for attracting natural mosquito populations.

Chemical Composition and Broad-Spectrum Insecticidal Activity of the Flower Essential Oil from an Ancient Sicilian Food Plant, Ridolfia segetum

Several species of the family Apiaceae are aromatic herbs that produce essential oils usable on an industrial scale for pharmaceutical, cosmetic, and food purposes. In particular, some essential oils, such as green insecticides for example, may replace synthetic insecticides, keeping most of their efficacy and avoiding environmental pollution or human poisoning. In the present study, we explored the insecticidal potential of Ridolfia segetum (L.) Moris essential oil (EO) against three different pests: Culex quinquefasciatus Say, Musca domestica L., and Spodoptera littoralis (Boisduval). For this purpose, the EO was obtained by hydrodistillation of flowers and its composition was achieved by gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS). This EO was rich in α-phellandrene (49.3%), β-phellandrene (9.2%), terpinolene (20.7%), and piperitenone oxide (5.9%). Concerning the mosquitocidal efficacy, the EO showed noteworthy toxicity against C. quinquefasciatus 3rd instar larvae, with a LC50 = 27.1 µL L−1 and LC90 = 42.5 µL L−1. Regarding M. domestica, a different toxicity of the R. segetum EO was found on male and female flies, calculating LD50 values of 10.5 and 50.8 µg adult−1, respectively. The EO was also toxic to S. littoralis 3rd instar larvae, achieving LD50 and LD90 values of 37.9 and 99.6 µg larva−1, respectively. Overall, this flower EO, extracted from a traditional Sicilian food plant, merits further investigation for the development of green insecticide formulations to be used in real world conditions, pending a careful assessment of non-target toxicity on beneficial organisms.

Characterization of Sites with Mosquito1 Larvae in the Metropolitan Region of Puebla, Mexico

Immature stages of mosquitoes (Diptera: Culicidae) were studied with the objective to characterize diversity and sites at the metropolitan region of Puebla, Mexico. Three weather periods (dry-cold, dry-hot, and wet) and two sampling methods (ovitraps and direct collection at larval habitats) were used. Seven species of mosquitoes were identified. Greatest richness and abundance were during the wet season with both sampling methods, but few mosquitoes were in ovitraps. Aedes epactius Dyar & Knab was dominant in the ovitraps. In larval habitats, dominant species were Ae. epactius and Culex quinquefasciatus Say. Sixty-one sites with developing mosquitoes were found and classified according to origin, location, and type. Characteristics such as insolation, organic matter, vegetation, and associated fauna of the sites were considered. Correspondence analysis determined preference patterns between species and sites. Ae. epactius, Culex restuans Theobald, and Cx. quinquefasciatus were opportunistic species, because they were found in a variety of larval habitats, whereas Culiseta particeps (Adams) and Culex stigmatosoma Dyar were generalist species. Cs. particeps was related to sites with accompanying fauna, and most individuals were collected in tires; Cx. stigmatosoma was associated with sites with vegetation in temporary puddles. Results can be important for improvement of entomological control and surveillance programs in the metropolitan region of Puebla.

Elevated Metabolic Enzymes and its Association with Insecticide Detoxification in Culex quinquefasciatus Say

Elevated Metabolic Enzymes and its Association with Insecticide Detoxification in Culex quinquefasciatus Say