The mosquitoes of Finland: updated distributions and bionomics.

Mosquitoes (Diptera: Culicidae) were collected in Finland between 2012 and 2018 to determine the species present and their distributions. In total, 52 466 specimens from 1031 collections formed the basis for the preparation of distribution maps for each of the 40 species that were collected. Anopheles maculipennis s.s., An. claviger, Aedes geminus and Ochlerotatus sticticus are confirmed on mainland Finland after previous records were uncertain or absent. Coquillettidia richiardii, Culiseta morsitans, Cs. ochroptera, Culex territans, Cx. torrentium, Oc. leucomelas, Oc. nigrinus, Oc. pullatus and Oc. punctodes occur more widely than previously reported. Three species, Ae. rossicus, Cs. subochrea and Oc. cyprius were not collected, although Ae. rossicus was subsequently found in Lapland by another researcher. No invasive species were collected. Ochlerotatus communis, an aggressive biter, was the most commonly encountered species. Larval collection data suggest that several species may have up to three generations per year in Finland, with Cx. torrentium and Cx. pipiens having at least two, and Oc. communis and Oc. punctor regularly found as larvae across the summer. These data, especially when coupled with historical records, are vital for monitoring species which have significant vector potential, particularly when faced with a warming climate.

Anopheles daciae, a new country record for Finland.

Mosquitoes (Diptera: Culicidae) were collected throughout Finland between 2013 and 2018 to determine species distributions. During the course of molecular identifications of specimens belonging to the Anopheles maculipennis complex, ribosomal internal transcribed spacer 2 sequences and link-reared specimens revealed the presence of Anopheles daciae Linton, Nicolescu & Harbach (n = 37), a new country record, as well as Anopheles messeae Falleroni (n = 19) in the collections. Although the sample size is low, distinctions are apparent in the distributions of these two species, with An. daciae present in south-eastern and central Finland, including the regions of Kanta-Häme, Pirkanmaa, Pohjois-Pohjanmaa, Päijät-Häme and Satakunta, and An. messeae present in the southern and south-eastern regions of Åland (Ahvenanmaa), Etelä-Savo, Kanta-Häme, Kymenlaakso, Päijät-Häme, Satakunta, Uusimaa and Varsinais-Suomi. All reports of An. messeae in Finland prior to 2018 should therefore be recognized as potentially being either An. messeae or An. daciae. Because these species are potential vectors of malarial protozoa, it is important to have full knowledge of their distributions across Europe, particularly in the face of climate warming.

The mosquito Anopheles (Cellia) oreios sp. n., formerly species 6 of the Australasian Anopheles farauti complex, and a critical review of its biology and relation to disease.

Species 6 of the Australasian Anopheles farauti sibling species complex (Diptera: Culicidae) is described and formally named Anopheles oreios Bangs & Harbach, sp. n. Adult, pupal and fourth-instar larval specimens collected in the Baliem Valley, Papua Province, Indonesia, are characterized and compared with those of Anopheles farauti, Anopheles hinesorum, Anopheles irenicus and Anopheles torresiensis (formerly informally denoted as species 1, 2, 7 and 3, respectively). The variable wings of adult females, the male genitalia, the pupa and the fourth-instar larva of An. oreios are illustrated and DNA sequence data are included for regions coding for sections of the mitochondrial COI and COII genes. The biology of An. oreios and its relation to malaria transmission are discussed in detail and contrasted with the biology and disease relations of some members of the An. farauti and Anopheles punctulatus sibling species complexes.

Mitochondrial DNA variation in the malaria vector Anopheles minimus across China, Thailand and Vietnam: evolutionary hypothesis, population structure and population history.

The effects of Pleistocene environmental fluctuations on the distribution and diversity of organisms in Southeast Asia are much less well known than in Europe and North America. In these regions, the combination of palaeoenvironmental reconstruction and inferences about population history from genetic data has been very powerful. In Southeast Asia, mosquitoes are good candidates for the genetic approach, with the added benefit that understanding the relative contributions of historical and current processes to population structure can inform management of vector species. Genetic variation among populations of Anopheles minimus was examined using 144 mtDNA COII sequences from 23 sites in China, Thailand and Vietnam. Haplotype diversity was high, with two distinct lineages that have a sequence divergence of over 2% and exhibit different geographical distributions. We compare alternative hypotheses concerning the origin of this pattern. The observed data deviate from the expectations based on a single-panmictic population with or without growth, or a stable but spatially structured population. However, they can be readily accommodated by a model of past fragmentation into eastern and western refugia, followed by growth and range expansion. This is consistent with the palaeoenvironmental reconstructions currently available for the region.

Molecular taxonomy of members of the Anopheles hyrcanus group from Thailand and Indonesia.

During studies of malaria vectors in Indonesia and Thailand, several specimens identified by field staff as members of the Anopheles barbirostris group (Diptera: Culicidae) were found to belong to the Anopheles hyrcanus group, as shown by marked differences in the size of the nuclear rDNA second internal transcribed spacer (ITS2) between the barbirostris (~1500 bp) and hyrcanus (~600 bp) groups. Identification of the species concerned required a more detailed study of ITS2 sequences and subunit I of the mitochondrial DNA cytochrome oxidase gene (COI). A phylogenetic analysis, based on Bayesian methods, revealed that the hyrcanus group specimens comprised five distinct clades, two of which corresponded with known species, Anopheles peditaeniatus and Anopheles sinensis. The remaining specimens formed three additional clades, for which there are no similar sequences in GenBank and which cannot be linked to previously described species. The misidentification of hyrcanus group species has important implications for malaria vector control; more comprehensive studies employing gene sequences are required to clarify the number of species in the group, their distribution and vector status.

Distribution and ecology of mosquitoes in a focus of dirofilariasis in northwestern Iran, with the first finding of filarial larvae in naturally infected local mosquitoes.

A study of the distribution and ecology of mosquitoes (Diptera: Culicidae) in Ardebil Province of northwestern Iran, with special reference to the known dirofilariasis focus in Meshkinshahr County, was carried out in July-August 2005 and April-October 2006. In total, 17,533 adult mosquitoes and 3090 third- and fourth-instar larvae were collected on 14 occasions and identified using morphological characters and DNA sequence data. Twenty species belonging to seven genera were found: Anopheles claviger (Meigen), An. hyrcanus (Pallas), An. maculipennis Meigen, An. pseudopictus Grassi*, An. sacharovi Favre, An. superpictus Grassi, Aedes vexans (Meigen)*, Coquillettidia richiardii (Ficalbi)*, Culex hortensis Ficalbi, Cx. modestus Ficalbi, Cx. pipiens Linnaeus, Cx. theileri Theobald, Cx. torrentium Martini*, Cx. tritaeniorhynchus Giles, Culiseta longiareolata (Macquart), Cs. annulata (Schrank)*, Cs. subochrea (Edwards), Ochlerotatus caspius (Pallas) s.l.* (= Aedes caspius sensu auctorum), Oc. geniculatus (Olivier)* (= Aedes geniculatus sensu auctorum) and Uranotaenia unguiculata Edwards (asterisks indicate new occurrence records for the province). The most prevalent species in adult catches were An. maculipennis (52%), Cx. theileri (45%) and Cx. hortensis (1%); the most prevalent species caught as larvae were Cx. theileri (27%), Cx. hortensis (21%) and An. maculipennis (19%). Anopheles maculipennis, Cx. pipiens and Cx. theileri were most widely distributed in the province. The occurrence of Cx. torrentium in Iran is verified based on differential characters of fourth-instar larvae. Anopheles maculipennis and An. sacharovi of the Maculipennis Group were identified from their diagnostic ITS2 sequences. For the first time, cytochrome c oxidase I (COI) sequences were obtained from Iranian specimens of An. hyrcanus, An. pseudopictus, Cx. theileri and Oc. caspiuss.l. Culex theileri and An. maculipennis were found naturally infected with third-stage (infective) larvae of Dirofilaria immitis (Leidy) and Setaria labiatopapillosa (Alessandrini) (Spirurida: Onchocercidae), respectively, for the first time in Iran.

A method for distinguishing the important malaria vectors Anopheles dirus and An. cracens (Diptera: Culicidae) based on antennal sensilla of adult females.

Some species of the Anopheles dirus species complex are considered to be highly competent malaria vectors in Southeast Asia. Anopheles dirus is the primary vector of Plasmodium falciparum and P. vivax while An. cracens is the main vector of P. knowlesi. However, these two species are difficult to distinguish and identify based on morphological characters. Hence, the aim of this study was to investigate the potential use of antennal sensilla to distinguish them. Large sensilla coeloconica borne on the antennae of adult females were counted under a compound light microscope and the different types of antennal sensilla were examined in a scanning electron microscope. The antennae of both species bear five types of sensilla: ampullacea, basiconica, chaetica, coeloconica and trichodea. Observations revealed that the mean numbers of large sensilla coeloconica on antennal flagellomeres 2, 3, 7, 10 and 12 on both antennae of both species were significantly different. This study is the first to describe the types of antennal sensilla and to discover the usefulness of the large coeloconic sensilla for distinguishing the two species. The discovery provides a simple, reliable and inexpensive method for distinguishing them.

Bionomics, taxonomy, and distribution of the major malaria vector taxa of Anopheles subgenus Cellia in Southeast Asia: an updated review.

There is high diversity of Anopheles mosquitoes in Southeast Asia and the main vectors of malaria belong to complexes or groups of species that are difficult or impossible to distinguish due to overlapping morphological characteristics. Recent advances in molecular systematics have provided simple and reliable methods for unambiguous species identification. This review summarizes the latest information on the seven taxonomic groups that include principal malaria vectors in Southeast Asia, i.e. the Minimus, Fluviatilis, Culicifacies, Dirus, Leucosphyrus, and Sundaicus Complexes, and the Maculatus Group. Main issues still to be resolved are highlighted. The growing knowledge on malaria vectors in Southeast Asia has implications for vector control programs, the success of which is highly dependant on precise information about the biology and behavior of the vector species. Acquisition of this information, and consequently the application of appropriate, sustainable control measures, depends on our ability to accurately identify the specific vectors.

Genetic diversity and molecular identification of mosquito species in the Anopheles maculatus group using the ITS2 region of rDNA.

The species diversity and genetic structure of mosquitoes belonging to the Anopheles maculatus group in Southeast Asia were investigated using the internal transcribed spacer 2 (ITS2) of ribosomal DNA (rDNA). A molecular phylogeny indicates the presence of at least one hitherto unrecognised species. Mosquitoes of chromosomal form K from eastern Thailand have a unique ITS2 sequence that is 3.7% divergent from the next most closely related taxon (An. sawadwongporni) in the group. In the context of negligible intraspecific variation at ITS2, this suggests that chromosomal form K is most probably a distinct species. Although An. maculatus sensu stricto from northern Thailand and southern Thailand/peninsular Malaysia differ from each other in chromosomal banding pattern and vectorial capacity, no intraspecific variation was observed in the ITS2 sequences of this species over this entire geographic area despite an extensive survey. A PCR-based identification method was developed to distinguish five species of the group (An. maculatus, An. dravidicus, An. pseudowillmori, An. sawadwongporni and chromosomal form K) to assist field-based studies in northwestern Thailand. Sequences from 187 mosquitoes (mostly An. maculatus and An. sawadwongporni) revealed no intraspecific variation in specimens from Thailand, Cambodia, mainland China, Malaysia, Taiwan and Vietnam, suggesting that this identification method will be widely applicable in Southeast Asia. The lack of detectable genetic structure also suggests that populations of these species are either connected by gene flow and/or share a recent common history.

Presence of Aedes albopictus in Lebanon and Syria.

The occurrence of Aedes albopictus in Lebanon and Syria is reported for the first time. Larvae were found in 4 localities in Lebanon, and 1 female was captured inside a house located in a coastal locality in Syria. The potential of the species to vector arboviral disease in the region is noted.

Confirmation of Anopheles varuna in vietnam, previously misidentified and mistargeted as the malaria vector Anopheles minimus.

Malaria control programs in Southeast Asia are faced with several questions concerning vector behavior and species identification, which need to be answered to consolidate and further improve the results of control practices. The vector system in Southeast Asia is complex because of the number of species potentially involved in malaria transmission. Additionally, the follow-up and evaluation of preventive control measures are hampered by the misidentification of vectors due to overlapping morphological characters of the female mosquitoes. In central Vietnam, control practices are aimed at 2 main species, Anopheles dirus s.l. and Anopheles minimus s.l. These reputed vectors were studied in an area of Binh Thuan Province of south-central Vietnam. Different collection methods were used to capture mosquitoes quarterly during a 1-year period. Mosquitoes were identified in the field and later subjected to detailed morphological examination and polymerase chain reaction-restriction fragment length polymorphism analysis. What was thought to be an unusual morphotype of An. minimus was shown to be Anopheles varuna, and most specimens identified as the former species in the field proved to be the latter species. Very few An. minimus individuals were found during the study period. The population of An. varuna was found to be highly zoophilic, and based on this behavior, it cannot be considered a vector in Vietnam. Because this species was previously being misidentified as An. minimus, a nonvector was mistargeted as a malaria vector in Binh Thuan Province. Anopheles dirus, which was found positive for Plasmodium falciparum circumsporozoite via enzyme-linked immunosorbent assay, is clearly the main vector in this area. Despite the fact that several potential secondary vectors were found during the study, the primary target for vector control in the region should be An. dirus.

Predictions of malaria vector distribution in Belize based on multispectral satellite data.

Use of multispectral satellite data to predict arthropod-borne disease trouble spots is dependent on clear understandings of environmental factors that determine the presence of disease vectors. A blind test of remote sensing-based predictions for the spatial distribution of a malaria vector, Anopheles pseudopunctipennis, was conducted as a follow-up to two years of studies on vector-environmental relationships in Belize. Four of eight sites that were predicted to be high probability locations for presence of An. pseudopunctipennis were positive and all low probability sites (0 of 12) were negative. The absence of An. pseudopunctipennis at four high probability locations probably reflects the low densities that seem to characterize field populations of this species, i.e., the population densities were below the threshold of our sampling effort. Another important malaria vector, An. darlingi, was also present at all high probability sites and absent at all low probability sites. Anopheles darlingi, like An. pseudopunctipennis, is a riverine species. Prior to these collections at ecologically defined locations, this species was last detected in Belize in 1946.

Conservation of the names Culex stigmatosoma and Culex thriambus.

As a result of action by the International Commission on Zoological Nomenclature, the name Culex peus Speiser is suppressed and never to be used as a valid name, and the names Culex stigmatosoma Dyar and Culex thriambus Dyar are conserved for the western banded foul-water mosquito and the related southwestern U.S. species, respectively.

Cytogenetic evidence for a fifth species within the taxon Anopheles dirus in Thailand.

Crossbreeding and chromosomal evidence are presented for the existence of a fifth sibling species within the taxon of Anopheles dirus in Thailand. The new species is morphologically identifiable as Anopheles balabacensis "Fraser's Hill form." Structural differences in mitotic chromosomes and extensive asynapsis in hybrid polytene chromosomes indicate that significant genetic divergence exists between this species and its closest relatives, An. dirus species A, B, C and D and An. balabacensis.

Cytogenetic evidence for two species within the current concept of the malaria vector Anopheles leucosphyrus in Southeast Asia.

Karyotypes and crossing relationships were investigated for three allopatric populations of Anopheles leucosphyrus in Southeast Asia: South Kalimantan, Sumatra and Thailand. The mitotic karyotypes of these populations were similar to those previously observed in other species of the An. leucosphyrus group. Populations from Thailand and South Kalimantan exhibited telocentric and subtelocentric sex chromosomes, respectively, with a distinctive band of intercalary heterochromatin in the X chromosome. Strikingly different submetacentric X and Y chromosomes were observed in the population from Sumatra, and it seems likely that the evolution of these chromosomes occurred through the acquisition of constitutive heterochromatin. Sterile F1 males were observed in crosses between the Sumatra population and the populations from South Kalimantan and Thailand. No genetic incompatibility was observed in crosses between the latter two populations. We believe that the present concept of An. leucosphyrus includes two allopatric species, one inhabiting Borneo, West Malaysia and southern Thailand and one confined to Sumatra.

Some entomological observations on malaria transmission in a remote village in northwestern Thailand.

Anopheline mosquitoes and their relation to malaria transmission were studied during the months of March, May and July in the Karen village of Mae Tha Waw located in the northwestern mountains of Tak Province. Thirteen species were captured on human bait during 80 man-nights of collecting. Four additional species were collected during routine larval surveys. Anopheles minimus and An. maculatus comprised 92.5% of the specimens captured biting man. Anopheles minimus and An. nivipes were implicated as vectors based on the detection of sporozoite infections using enzyme-linked immunosorbent assays for Plasmodium falciparum and P. vivax. Anopheles dirus was rarely encountered and probably played little part in transmission in Mae Tha Waw during the period of study. Information is provided on nightly biting activity, incidence of disease, infectivity and larval bionomics.

Wyeomyia (Prosopolepis) confusa (Lutz): subgeneric validation, species description, and recognition of Wyeomyia flui (Bonne-Wepster and Bonne) as the senior synonym of Wyeomyia kerri del Ponte and Cerqueira.

Prosopolepis Lutz is validated as a monotypic subgenus of Wyeomyia Theobald and the type species, Weomyia confusa (Lutz), is redescribed. The description includes illustrations of the male and female genitalia, the 4th-stage larva, and the pupa. Prosopolepis flui Bonne-Wepster and Bonne is resurrected from synonymy with Wy. confusa and recognized as the senior synonym of Wyeomyia kerri del Ponte and Cerqueira. Wyeomyia flui does not belong in the subgenus Prosopolepis and remains in the genus Wyeomyia without subgeneric placement. Trichoprosopon pusillum Lutz and Nuñez-Tovar is not synonymous with Wy. confusa and is provisionally regarded as a nomen dubium within Wyeomyia. The identity of Wy. confusa is fixed by neotype selection.

A new species of the Hyrcanus Group of Anopheles, subgenus Anopheles, a secondary vector of malaria in coastal areas of southern Vietnam.

Anopheles (Anopheles) nimpe, a new species of the Hyrcanus Group from the coastal areas of southern Vietnam, is described and illustrated in the adult, pupal, and larval stages. Partial DNA sequence data from paratypes are included for the mitochondrial cytochrome c oxidase I and 16S rRNA genes. The species is distinguished from other members of the group occurring in Southeast Asia.

Relative repellency of two formulations of N,N-diethyl-3-methylbenzamide (deet) and permethrin-treated clothing against Culex sitiens and Aedes vigilax in Thailand.

Field tests were conducted to compare the effectiveness of 2 repellent formulations of N,N-diethyl-3-methylbenzamide (deet) in combination with permethrin-impregnated military uniforms against Culex sitiens and Aedes vigilax in Thailand. Repellency was determined during a 2 h crepuscular period using volunteers who had been treated with repellents 6, 8, 10, and 12 h prior to the end of each test period. An extended-duration repellent formulation (EDRF) containing 35% deet repelled significantly more Ae. vigilax than 75% deet in ethanol. Although not statistically significant, the EDRF also resulted in fewer biting attempts by Cx. sitiens. Neither formulation provided complete protection against either species 4-12 h post-application, but both provided greater overall protection against Ae. vigilax. Volunteers who wore treated uniforms without repellents were attacked by significantly fewer mosquitoes than controls.

Some observations on sympatric populations of the malaria vectors Anopheles leucosphyrus and Anopheles balabacensis in a village-forest setting in South Kalimantan.

Human bait collections of biting anopheline mosquitoes were made on five consecutive nights during September 1986 in a remote village located in a heavily forested area of South Kalimantan, Indonesia. Anopheles leucosphyrus and An. balabacensis comprised 97.7% of the total number of specimens collected outside houses in the village. Anopheles balabacensis were slightly fewer in total numbers than leucosphyrus. Mosquitoes were collected simultaneously in the village and the forest on two nights. The numbers of leucosphyrus and balabacensis biting in the forest were small in comparison with the populations encountered in the village. Approximately 75% of the specimens were checked individually for sporozoite infections using ELISA for P. falciparum and P. vivax. Sporozoites of P. falciparum were detected in one specimen of leucosphyrus and one of balabacensis. The sporozoite infection rate was 1.0% for leucosphyrus and 1.3% for balabacensis.