Aquatic Phoretic Mites (Acari: Hydrachnidia) Associated with Ectoparasitism of Mosquitoes (Diptera: Culicidae) in the Midwest Region of Brazil

Water mites (Hydrachnidia) are common external parasites of the medically important mosquitoes (Culicidae). Between April 2014 and April 2015, 64 mites from three genus, Arrenurus 71.9%, Limnochares 3.1%, and Hydrachna 25.0%, were collected from female mosquitoes in two rural locations near Cuiabá, Mato Grosso, Brazil. Dipterous species parasitized by water mites belonging to seven species: Anopheles (Nys.) darling, An. evansae, Aedes (Och.) scapularis, Ae. serratus, Mansonia (Man.) wilsoni, Psorophora (Jan.) ferox, Ps. varipes. The most common specimens to accommodate the water mites were Anopheles (Nys.) darlingi and Psorophora (Jan.) varipes. The prevalence of parasitism of mosquitoes by water mites found in this study was less than 5. However, few studies have addressed the ecological role of mites and their biotopes, as well as host-parasite interactions in Brazil.

Aquatic Phoretic Mites (Acari: Hydrachnidia) Associated with Ectoparasitism of Mosquitoes (Diptera: Culicidae) in the Midwest Region of Brazil

Water mites (Hydrachnidia) are common external parasites of the medically important mosquitoes (Culicidae). Between April 2014 and April 2015, 64 mites from three genus, Arrenurus 71.9%, Limnochares 3.1%, and Hydrachna 25.0%, were collected from female mosquitoes in two rural locations near Cuiabá, Mato Grosso, Brazil. Dipterous species parasitized by water mites belonging to seven species: Anopheles (Nys.) darling, An. evansae, Aedes (Och.) scapularis, Ae. serratus, Mansonia (Man.) wilsoni, Psorophora (Jan.) ferox, Ps. varipes. The most common specimens to accommodate the water mites were Anopheles (Nys.) darlingi and Psorophora (Jan.) varipes. The prevalence of parasitism of mosquitoes by water mites found in this study was less than 5. However, few studies have addressed the ecological role of mites and their biotopes, as well as host-parasite interactions in Brazil.

Mitogenome-based phylogeny of mosquitoes(Diptera:Culicidae)

Mosquitoes are of great medical significance as vectors of many deadly diseases.Mitogenomes have been widely used in phylogenetic studies,but mitogenome knowledge within the family Culicidae is limited,and Culicidae phylogeny is far from resolved.In this study,we surveyed the mitogenomes of 149 Culicidae species,including 7 newly sequenced species.Comparative analysis of 149 mosquito mitogenomes shows gene composition and order to be identical to that of an ancestral insect,and the AT bias,length variation,and codon usage are all consistent with that of other reported Dipteran mitogenomes.Phylogenetic analyses based on the DNA sequences of the 13 protein-coding genes from the 149 species robustly support the monophyly of the subfamily Anophelinae and the tribes Aedini,Culicini,Mansonini,Sabethini,and Toxorhynchitini.To resolve ambiguous relationships between clades within the subfamily Culicinae,we performed topological tests and show that Aedini is a sister to Culicini and that Uranotaenini is a sister to(Mansonini)+(Toxorhynchitini+Sabethini).In addition,we estimated divergence times using a Bayesian relaxation clock based on the sequence data and 3 fossil calibration points.The results show mosquitoes diverged during the Early Jurassic with massive Culicinae radiations during the Cretaceous,coincident with the emergence of angiosperms and the burst of mammals and birds.Overall,this study,which uses the largest number of Culicidae mitogenomes sequenced to date,comprehensively reveals the mitogenome characteristics and mitogenome-based phylogeny and divergence times of Culicidae,providing information for further studies on the mitogenome,phylogeny,evolution,and taxonomic revision of Culicidae.

Evaluation of the Effectiveness of “Electron Go out Mosquito Small Lamp” in Disease Vector Mosquito Control Benin West Africa

In the context of mosquito control, a plethora of devices have been put on the market. The effectiveness of these devices is not always proven, but some have interesting principles that have the potential to be a good means of mosquito control. Among these interesting devices are the photonic traps. We have carried out nightly captures of mosquitoes on human baits in the presence and absence of the device. These captures were made during the rainy season in the localities of Zogbadjè and Mènontin. The captures were made under the same atmospheric conditions at the same locations at 5-day intervals. These captures were made twice per house, indoors and outdoors, with one blank capture without the device and one capture with the device. The captured mosquitoes were identified and classified by genus and their aggressiveness determined by calculating the biting rate. A total of 845 mosquitoes were captured during these captures with 296 mosquitoes captured indoors without the device and 132 mosquitoes with the device present. This represents a decrease of 55.40% in culicidae density. Furthermore, a significant decrease was observed in aggressiveness, from 49 to 22 bites per man per night (b/m/n) with the use of the device. This decrease is even more important for nocturnal species such as Anopheles spp. whose aggressiveness decreased by 90%. The present study confirms the effectiveness of the “Electron go out mosquito small lamp” in reducing Culicidae density and mosquito aggression even in the presence of chemotactic interference. However, this study was limited in time and focused only on the ability of the device to reduce mosquito numbers and did not assess its epidemiological efficacy. It is therefore important to extend the work to examine the influence of the use of this device on population health and the occurrence of mosquito-borne diseases, particularly malaria.

中国蚊科分类研究新进展

蚊科(Culicidae)昆虫中很多种类是重要的媒介昆虫,蚊科分类研究已有200多年的发展历程。2000年以来,Harbach等人依据比较解剖学、支序分类和分子生物学技术对蚊科分类系统进行了重大修订,把蚊科类群从原来的34属修订为112属,建立了更加细分的蚊科分类系统。中国蚊虫研究近些年来也发展迅猛,蚊虫研究者对中国蚊虫属、种组及隐存种等做了大量订正,调整和新增记录,中国现已知蚊虫达46属418种。本文依据Harbach新分类系统对中国蚊科分类现状和分子分类学研究进展进行了总结,中国按蚊亚科(Anophelinae)现有1属62种,库蚊亚科(Culicinae)45属356种。由于形态分类学的局限以及在蚊科内广泛存在的隐存种,对传统蚊科分类提出了新的挑战,随着分子分类技术的发展,大量基于分子技术的研究揭示并改进了蚊虫的分类。目前仍有大量的蚊科分类和系统发育问题尚有待澄清。

Habitat productivity and pyrethroid susceptibility status of Aedes aegypti mosquitoes in Dar es Salaam,Tanzania

Background:Aedes aegypti(Diptera:Culicidae)is the main vector of the dengue virus globally.Dengue vector control is mainly based on reducing the vector population through interventions,which target potential breeding sites.However,in Tanzania,little is known about this vector’s habitat productivity and insecticide susceptibility status to support evidence-based implementation of control measures.The present study aimed at assessing the productivity and susceptibility status of A.aegypti mosquitoes to pyrethroid-based insecticides in Dar es Salaam,Tanzania.Methods:An entomological assessment was conducted between January and July 2015 in six randomly selected wards in Dar es Salaam,Tanzania.Habitat productivity was determined by the number of female adult A.aegypti mosquitoes emerged per square metre.The susceptibility status of adult A.aegypti females after exposure to 0.05%deltamethrin,0.75%permethrin and 0.05%lambda-cyhalothrin was evaluated using the standard WHO protocols.Mortality rates were recorded after 24 h exposure and the knockdown effect was recorded at the time points of 10,15,20,30,40,50 and 60 min to calculate the median knockdown times(KDT50 and KDT95).Results:The results suggest that disposed tyres had the highest productivity,while water storage tanks had the lowest productivity among the breeding habitats Of A.aegypti mosquitoes.All sites demonstrated reduced susceptibility to deltamethrin(0.05%)within 24 h post exposure,with mortalities ranging from 86.3±1.9(mean±SD)to 96.8±0.9(mean±SD).The lowest and highest susceptibilities were recorded in Mikocheni and Sinza wards,respectively.Similarly,all sites demonstrated reduced susceptibility permethrin(0.75%)ranging from 83.1±2.1%(mean±SD)to 96.2±0.9%(mean±SD),in Kipawa and Sinza,respectively.Relatively low mortality rates were observed in relation to lambda-cyhalothrin(0.05%)at all sites,ranging from 83.1±0.7(mean±SD)to 86.3±1.4(mean±SD).The median KDT_(50)for deltamethrin,permethrin and lambda-cyhalothrin were 24.9-30.3 min,24.3-34.4 min and 26.7-32.8 min,respectively.The KDT_(95)were 55.2-90.9 min for deltamethrin,54.3-94.6 min for permethrin and 64.5-69.2 min for lambda-cyhalothrin.Conclusions:The productive habitats for A.aegypti mosquitoes found in Dar es Salaam were water storage containers,discarded tins and tyres.There was a reduced susceptibility of A.aegypti to and emergence of resistance against pyrethroid-based insecticides.The documented differences in the resistance profiles of A.aegypti mosquitoes warrants regular monitoring the pattern concerning resistance against pyrethroid-based insecticides and define dengue vector control strategies.