The Anopheles punctulatus group of mosquitoes in the Solomon Islands and Vanuatu surveyed by allozyme electrophoresis

Abstract. Four species within the Anopheles punctulatus group of mosquitoes (Diptera: Culicidae) were identified by allozyme analysis of samples collected from thirty-three localities in Guadalcanal, Makira, Malaita, Temotu and Western Provinces in the Solomon Islands and six localities on Efate, Espiritu Santo, Maewo and Malekula Islands in Vanuatu. Three of these species are members of the An. farauti complex. A key is given to identify five species of the An. punctulatus group known to occur in the Solomon Islands using their isoenzyme characteristics.
An. farauti No. 1 was widespread in coastal areas of the Solomon Islands and was the only species detected in Vanuatu, including Efate Island (where Faureville is the type locality of An. farauti Laveran sensu stricto). An. farauti No. 2 and An. punctulatus were common in the Solomon Islands in more inland areas. An. farauti No. 7, reported here for the first time, was found as larvae in freshwater at six localities on north Guadalcanal. Three other members of the An. punctulatus group which have been reported previously from the Solomon Islands: An. koliensis, An. renellensis and an electrophoretic variant of An. farauti sensu lato, were not found in our samples.
Previously recognized vectors of malaria and bancroftian filariasis in the Solomon Islands are An. farauti No. 1 (i.e. An. farauti s.s. ), An. koliensis and An. punctulatus s. s. Adult females of An. farauti No. 2 and An. farauti No. 7 were not attracted to human bait in areas where their larvae occurred, indicating that these two species are not anthropophilic and therefore unlikely to transmit human pathogens.     

Shared salinity tolerance invalidates a test for the malaria vector Anopheles farauti s.s. on Guadalcanal, Solomon Islands

Among the Punctulatus Group of Anopheles mosquitoes (Diptera: Culicidae), first-instar larvae of the medically unimportant freshwater Anopheles farauti species No. 7 survives a seawater tolerance test (SST) that was previously thought to be diagnostic for the saltwater-tolerant malaria vector species, An. farauti Laveran s.s. Salt tolerance in these two closely related isomorphic species appears to be a shared derived character within the Farauti Complex. Failure to differentiate An. farauti s.s. from An. farauti No. 7 will overestimate potential malaria vector numbers and waste limited larval control resources. Use of the SST should therefore be discontinued on Guadalcanal and other techniques such as allozyme electrophoresis used instead.     

Shared salinity tolerance invalidates a test for the malaria vector Anopheles farauti s.s. on Guadalcanal, Solomon Islands [corrected

Among the Punctulatus Group of Anopheles mosquitoes (Diptera: Culicidae), first-instar larvae of the medically unimportant freshwater Anopheles farauti species No. 7 survives a seawater tolerance test (STT) that was previously thought to be diagnostic for the saltwater-tolerant malaria vector species, An. farauti Laveran s.s. Salt tolerance in these two closely related isomorphic species appears to be a shared derived character within the Farauti Complex. Failure to differentiate An. farauti s.s. from An. farauti No.7 will overestimate potential malaria vector numbers and waste limited larval control resources. Use of the STT should therefore be discontinued on Guadalcanal and other techniques such as allozyme electrophoresis used instead [corrected].     

Impact of permethrin-impregnated mosquito nets compared with DDT house-spraying against malaria transmission by Anopheles farauti and An.punctulatus in the Solomon Islands

Abstract. In villages of northern Guadalcanal in the Solomon Islands, where the predominant malaria vector is An.farauti No. 1 and An. puctulatus is also involved, malaria transmission rates were compared for three zones: (1) non-intervention: 438 people in seventeen villages; (2) residual DDT house-spraying two cycles per year: 644 people in thirty villages; (3) bednets impregnated with permethrin 0.5 g/m² twice per year, used by 580 people in sixteen villages. Regular DDT spraying in zones 1 and 3 had been withdrawn 18 months previously. Malariological blood smear surveys of children aged 1-9 years in August 1986 to January 1987 showed a mean-baseline malaria parasite rate of 38% (32/84). By February 19 88 , 18 months after introduction of impregnated bednets, the Plasmodium falciparum infection rate in children was lowest in the zone using impregnated bednets (21% of 29), intermediate in the untreated zone (29% of 34) and highest in the DDT zone (46% of 53), but these differences were not statistically significant. P.vivax infection rates were 9–14%. Using ELISA tests for malaria circumsporozoite antigen in the vectors, overall positivity rates were 0.7% of 49 ,902 An.farauti and 2.54% of 118 An.punctulatus, comprising 228 P.falciparum and 124 P. vivax infections. In the study zones, vector positivity rates were 0.93% of 31 ,615 An.farauti in the untreated zone; 0.32% of 16, 883 An.farauti in the DDT zone; 0.07% of 1404 An.farauti and 2.54% of 118 An.puctulatus in the impregnated bednet zone. There was no significant correlation between malaria parasite rates in the vectors and the children. Entomological inoculation rates were consistently highest in the untreated zone (1.6–2.8 infective bites/night), intermediate in the DDT zone (0.8– 1.1/night) and significantly lowest in the bednet zone (0.03-0.23/night). Geometric mean densities of P.falciparum sporozoites were also significantly higher in the DDT zone (50% > 10,000 sporozoites/mosquito compared with 20% in untreated zone). The highest individual infection density was an estimated 52,080 sporozoites of P.falciparum in a specimen of An.punctulatus from the bednet zone. P.vivax sporozoite densities were not significantly different between zones, and both species of vector had similar mean sporozoite loads for both species of malaria. It is concluded that permethrin-impregnated mosquito nets exerted significantly more impact on vector infectivity and the inoculation rate than resulted from DDT spraying. Even so, the inoculation rate for people in the bednet zone remained at one infective bite every 4–32 days, an insufficient reduction to control malaria without additional countermeasures. Ineffectiveness of house-spraying and the limited impact of impregnated bednets are attributed to exophily and other behavioural aspects of An. farauti.     

DNA probes to identify members of the Anopheles farauti complex

DNA probes have been constructed to distinguish between the members of the Anopheles farauti complex of mosquitoes known as species numbers 1, 2 and 3. Partial genomic libraries of the three known species were exposed to labelled total genomic DNA from each species. Colonies showing differential hybridization were selected for further testing. These probes were found which allow identification of the three known species: probe pAf1 (160 bp fragment) hybridizes to DNA from An. farauti nos. 1 and 2; probe pAf2 (95 bp fragment) hybridizes to DNA from An. farauti no. 2 only; and probe pAf3 (1.3 kb fragment) hybridizes strongly to DNA from An. farauti no. 3, less to no. 1 and faintly to no. 2. Increasing the stringency of hybridization reduced the cross-hybridization of probes pAf1 and pAf3. Only radioactively labelled probes were tested. Males and females and individuals from diverse habitats and localities showed the same species/probe hybridization characteristics. This technique allows faster identification of the sibling species than previous methods, and has the added advantage that it allows air-dried and alcohol stored specimens to be identified.     

Electrophoretic keys to identify members of the Anopheles punctulatus complex of vector mosquitoes in Papua New Guinea

Abstract. Electrophoretic keys are given for the six species of the Anopheles punctulatus complex (Diptera: Culicidae) known from Papua New Guinea plus An.farauti No. 2 and No. 3 from Australia. The categories ‘faster’, ‘standard’ and ‘slower’ are used in keys to relate allozyme band migration following cellulose acetate electrophoresis to the standard pattern. Alternative keys are given depending on the availability of different species for use as standards.     

Allozyme analysis reveals six species within the Anopheles punctulatus complex of mosquitoes in Papua New Guinea

Abstract. Among samples collected from nineteen localities in Papua New Guinea, we have identified six species within the Anopheles punctulatus complex of mosquitoes, by means of cellulose acetate allozyme electrophoresis. An.punctulatus Dönitz sensu stricto was collected from seven villages in the Madang area and from Buksak, Sausi Mission and an area 18 km SW of Tari; An.koliensis Owen from eight villages in the Madang area, from Popondetta and Brown River near Karema; and An.farauti No. 1 from ten coastal areas including Madang, Lorengau, Popondetta, Port Moresby, Rabaul and Wewak. Three newly recognized species, reported here for the first time, are designated as An.farauti No. 4 from Gonoa and Hudini, Madang area; An.farauti No. 5 from Ketarabo near Goroka; and An.farauti No. 6 from Hiwanda near Tari. Three other known members of the complex, An.clowi Rozeboom & Knight, An.farauti No. 2 (Bryan, 1973) and An.farauti No. 3 (Mahon & Meithke, 1982) were not detected in Papua New Guinea. Problems arising with morphological characters for the identification of species in this group are discussed.     

Seasonal abundance and biting behaviour of Anopheles punctulatus and An.koliensis in Malaita Province, Solomon Islands, and a trial of permethrin impregnated bednets against malaria transmission

Seasonal abundance of the malaria vectors Anopheles punctulatus Donitz and An.koliensis Owen in Bilimanu, an isolated inland village with forty-two houses in Malaita Province of the Solomon Islands, was monitored over 28 months by means of all-night landing/biting catches at one site during June 1985 to September 1987. Totals of 1250 An.punctulatus and 141 An.koliensis were collected, the latter being the largest number of this species ever caught at any locality in the Solomons. Bednets impregnated with permethrin 0.5 g/m² were introduced in December 1986 to be used at night by all 190 villagers for protection against malaria vectors. Bioassay tests with An.punctulatus blood-fed females exposed under nets for lOmin resulted in 100% mortality up to 50 weeks post-impregnation. For An.punctulatus, the main vector species, the mean catch (indoors + outdoors) per man hour was 2.9 (range 0.7–13.2) before a cyclone on 19 May 1986, and, 0.66 (0.2-2.7) after the cyclone. The vector survival rates were usually high before the cyclone, but erratically lower thereafter for An.punctulatus. An.koliensis disappeared after the cyclone. Both An.punctulatus and An.koliensis consistently showed higher rates of biting man indoors than outdoors and their diel biting cycle showed a peak around midnight. Outdoors, the parous proportion of An.punctulatus was twice the nulliparous, and nearly so indoors. Following intervention with permethrin-treated bednets, the mean catch of An.punctulatus fell to 0.35 per man-hour (monthly range 0–1.5). The Plasmodium falciparum malaria infection rate reduced from 10% pre-intervention to zero in September 1987, 9 months after intervention, and then rose again. With re-impregnation of bednets in November 1987, the P.falciparum infection rate was again reduced by March 1988. No effect of treated bednets was observed on the prevalence of P.vivax malaria.     

Simultaneous identification of species and molecular forms of the Anopheles gambiae complex by PCR-RFLP

For differential identification of sibling species in the Anopheles gambiae Giles complex (Diptera: Culicidae), including simultaneous separation of M and S molecular forms within An. gambiae Giles sensu stricto, we describe a PCR-RFLP method. This procedure is more efficient, faster and cheaper than those used before, so is recommended for large-scale processing of field-collected larval and adult specimens to be identified in malaria vector studies.     

Responses of mosquitoes of the Anopheles farauti complex to 1-octen-3-ol and light in combination with carbon dioxide in northern Queensland, Australia

Abstract. In northern Queensland, Australia, three experiments were conducted to determine the response of mosquitoes of the Anopheles farauti complex to CDC traps baited with four attractant combinations: octenol + C0₂ and light; octenol and light; CO, and light; or C0₂ and octenol without light. A CDC-modified updraft light-trap was also trialled, but did not significantly enhance collections of An.farauti sensu lato. The combination of light, octenol and C0₂ caught significantly more An.farauti s.l. (both An.farauti No. 1 and No. 2 sibling species) when compared to C0₂ and light alone. Only small numbers of the An.farauti complex were captured when CDC traps were baited with octenol alone, i.e. no light or C0₂.     

Use of rDNA-PCR to investigate the ecological distribution of Anopheles bwambae in relation to other members of the An.gambiae complex of mosquitoes in Bwamba County, Uganda

Abstract Environmental relationships were investigated among three species of the Anopheles gambiae complex of mosquitoes associated with the geothermal springs located in Bwamba County, Uganda. The degree of ecological isolation between An.gambiae and An. bwambae, a sibling species known only from the geothermal springs environment, was assessed on the basis of adult distribution and abundance as well as differences in larval habitats. Field data were gathered during June 1995 without knowing which of the species were being collected. Specimens identified subsequently by rDNA-PCR were used to interpret the ecological data. Ten of twenty aquatic sites sampled were found positive for immature stages of the An.gambiae complex. Larvae of An.bwambae were associated with ‘springwater’ habitats having much higher conductivity, much greater concentrations of dissolved solids and slightly higher temperature and pH than ‘normal’ fresh water sites inhabited by larvae of An.gambiae. Larval habitats of both species were unshaded: An.bwambae occurred among dense sedge (Cyperus laevigatus) whereas those of An.gambiae were almost devoid of vegetation. One mixed sample showed that larvae of both species occur together in peripheral aquatic sites with intermediate physical and ecological characteristics. In water preference tests, free-flying females were reluctant to lay eggs on bowls of water in cages; gravid females (with one wing amputated) placed on the surface of water in a cup laid eggs on seasoned rainwater (12/51 An.bwambae; 2/3 An.gambiae) as well as spring-water (39/51 An.bwambae; 1/3 An.gambiae). All three An.gambiae oviposited on the first water option, whereas 86% of An. bwambae witheld oviposition until being moved to the other type of water after 5–6 h, and 82% (36/44) of these laid eggs on geothermal water in preference to rainwater. Larval and adult collections showed that An.gambiae occurs sympatrically with An.bwambae throughout its range in the humid foothill environment of the geothermal springs, whereas the distribution of An.arabiensis overlaps only slightly with An.bwambae towards the savanna environment north of the springs.     

Impact of untreated bednets on prevalence of Wuchereria bancrofti transmitted by Anopheles farauti in Papua New Guinea

Abstract Despite the growing evidence that insecticide‐treated mosquito nets reduce malaria morbidity and mortality in a variety of epidemiological conditions, their value against lymphatic filariasis infection and disease is yet to be established. The impact of untreated bednets on the prevalence of Wuchereria bancrofti (Cobbold) (Nematoda: Filarioidea) infection and disease was investigated on Bagabag island in Papua New Guinea, where both malaria and filariasis are transmitted by the same vector mosquitoes of the Anopheles punctulatus Dönitz group (Diptera: Culicidae). Community‐wide surveys were conducted recording demographic characteristics including bednet usage. Physical examinations for hydrocoele and lymphoedema were performed and blood samples assessed for filarial and malaria parasites. Mosquitoes were sampled using the all‐night landing catch method and individually dissected to determine W. bancrofti infection and infective rates. Bednet usage among residents was 61% and the mean age of users (25.6 years) was similar to non‐users (22.5 years). Anopheles farauti Laveran was the only species were found to contain filarial larvae: 2.7% infected (all stages), 0.5% infective (L3). The overall W. bancrofti microfilaraemia and antigenaemia rates were 28.5% and 53.1%, respectively. Bednet users had lower prevalence of W. bancrofti microfilaraemia, antigenaemia and hydrocoele rates than non‐users. In comparison, untreated bednets had no effect on the prevalence and intensity of Plasmodium falciparum and P. vivax infections. The impact of bednet usage on rates of microfilaraemia and antigenaemia remained significant even when confounding factors such as age, location and sex were taken into account, suggesting that untreated bednets protect against W. bancrofti infection.     

PCR assay for identification of Anopheles quadriannulatus species B from Ethiopia and other sibling species of the Anopheles gambiae complex

Sibling species A and B of Anopheles quadriannulatus (Theobald) are recognized as allopatric members of the Anopheles gambiae Giles complex of Afrotropical mosquitoes (Diptera: Culicidae). Species A represents An. quadriannulatus sensu stricto, widespread in southern Africa, whereas An. quadriannulatus species B occurs in Ethiopia. Because of difficulty of identification, distribution of An. quadriannulatus sensu lato remains poorly known. Cytotaxonomy and the standard DNA polymerase chain reaction (PCR) assay do not distinguish between species A and B of An. quadriannulatus. By optimizing the standard PCR assay (Scott et al., 1993) for identification of members of the An. gambiae complex, we identified two discriminant fragments of 153 bp and 900 bp from DNA of An. quadriannulatus species B, whereas only the 153 bp fragment was amplified for species A from South Africa. This modified PCR assay can therefore be used to distinguish between species A and B of An. quadriannulatus s.l. as well as other members of the An. gambiae complex.     

Presence of Anopheles culicifacies B in Cambodia established by the PCR-RFLP assay developed for the identification of Anopheles minimus species A and C and four related species

Abstract A polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) assay developed for identification of five species of the Anopheles minimus Theobald group and a related mosquito species of the Myzomyia Series (Diptera: Culicidae) was applied to morphologically identified adult female specimens collected in Ratanakiri Province, north‐eastern Cambodia. In addition to finding An. aconitus Dönitz, An. minimus species A and An. pampanai Büttiker & Beales, some specimens showed a new restriction banding pattern. Siblings of specimens that exhibited this new PCR‐RFLP pattern were morphologically identified as An. culicifacies James sensu lato. Based on nucleotide sequences of the ribonuclear DNA internal transcribed spacer 2 region (ITS2) and the mitochondrial cytochrome oxidase I gene (COI), these specimens were recognized as An. culicifacies species B (sensu Green & Miles, 1980 ), the first confirmed record of the An. culicifacies complex from Cambodia. This study shows that the PCR‐RFLP assay can detect species not included in the initial set‐up and is capable of identifying at least seven species of the Myzomyia Series, allowing better definition of those malaria vector and non‐vector anophelines in South‐east Asia.     

Cannibalism and predation among larvae of the Anopheles gambiae complex

Among the aquatic developmental stages of the Anopheles gambiae complex (Diptera: Culicidae), both inter- and intra-specific interactions influence the resulting densities of adult mosquito populations. For three members of the complex, An. arabiensis Patton, An. quadriannulatus (Theobald) and An. gambiae Giles sensu stricto, we investigated some aspects of this competition under laboratory conditions. First-instar larvae were consumed by fourth-instar larvae of the same species (cannibalism) and by fourth-instar larvae of other sibling species (predation). Even when larvae were not consumed, the presence of one fourth-instar larva caused a significant reduction in development rate of first-instar larvae. Possible implications of these effects for population dynamics of these malaria vector mosquitoes are discussed.     

Population genetic confirmation of species status of the malaria vectors Anopheles willmori and An.pseudowillmori in Thailand and chromosome phylogeny of the Maculatus group of mosquitoes

Among the Anopheles (Cellia) maculatus group of Oriental mosquitoes, positive assortative mating occurs within sympatric and synchronous populations of An.willmori and An.pseudowillmori in the presence of populations of An.maculatus and An.sawadwongporni, judged from the occurrence of inversion homozygotes and the absence of any heterozygotes in their distinctive, polytene chromosomes. Genotypic frequencies for enzyme electromorphs give additional evidence for the species status of An.pseudowillmori and a practical means of identification in field studies of malaria vectors. Autosomal rearrangements are referred to those of An.stephensi which is unique for 4y. An.willmori differs by a single inversion, 4x; An.pseudowillmori by three Arm 2 inversions; and An.dispar by one Arm 2 inversion and 4x. Fixed autosomal rearrangements in the Maculatus group are summarized and their phylogenetic distribution suggests some unknown, intrinsic mechanism by which genome structure is disrupted in association with speciation events. This could be relevant to the potential genetic manipulation of malaria vectors.     

Molecular and morphological studies on the Anopheles minimus group of mosquitoes in southern China: taxonomic review,distribution and malaria vector status

Abstract. Mosquitoes of the Anopheles minimus group (Diptera: Culicidae) from nine Provinces of southern China were identified morphologically and by molecular characterization, using single‐strand conformation polymorphisms (SSCPs) and sequence data for the D3 region of the 28S ribosomal DNA and the mitochondrial COII locus. Species A and C (sensu Green et al., 1990 ) of the An. minimus complex were found to be sympatric in Yunnan Province. Species A occurs eastward from Yunnan through southern Guangxi, Hainan, Guangdong and Taiwan Provinces, whereas species C occurs northward to northern Guangxi, Guizhou and Sichuan Provinces. Morphological and molecular evidence (based on specimens from the field and four isofemale lines) shows that An. minimus forms A and B (sensu Yu & Li, 1984 ) are morphological variants of species A, which is accepted as An. minimus Theobald sensu stricto (type‐locality: Pokfulam, Hong Kong). The so‐called subspecies x of An. minimus (sensu Baba, 1950 ) is reinterpreted as An. aconitus Dönitz. The distribution and vector status of members of the An. minimus group are discussed in relation to the historical and current transmission of malaria and filariasis in China. Both An. minimus A and C have been implicated as widespread vectors of malaria, whereas only species A has been found in Hainan, where An. minimus s.l. was a vector of Bancroftian filariasis. The presence of An. aconitus in Hainan and Yunnan Provinces is confirmed, but the occurrence of An. varuna Iyengar and An. fluviatilis James, which were previously recorded in China, could not be verified.     

Population genetic evidence for species A, B, C and D of the Anopheles dirus complex in Thailand and enzyme electromorphs for their identification

Mixtures of chromosomal forms A, B, C and D in natural populations of Anopheles dirus Peyton & Harrison sensu lato in Thailand show significant positive values of Wright's fixation index for six enzyme-electromorph loci. The mean value of FIS over all loci was found to be +0.28 (SD 0.02), with a range of +0.57 (Odh) to +0.10 (Idh-2). Partitioning electromorph data for the chromosomal forms reduces the mean FIS to 0.03 (SD 0.01), which suggests that positive assortative mating is a characteristic of each form. This supports the hypothesis that the chromosomal/electrophoretic forms A, B, C and D represent four distinct biological species within the An. dirus complex. An example is given of the use of enzyme electromorphs as a means of vector identification during a malaria entomological field study involving a mixture of An. dirus species A and D. Electromorph identifications of 323 sp. A and 161 sp. D were more than 98% correct when cross-referenced to specific DNA probes.     

Molecular differentiation of three closely related members of the mosquito species complex, Anopheles moucheti, by mitochondrial and ribosomal DNA polymorphism

Distinction between members of the equatorial Africa malaria vector Anopheles moucheti (Evans) s.l. (Diptera: Culicidae) has been based mainly on doubtful morphological features. To determine the level of genetic differentiation between the three morphological forms of this complex, we investigated molecular polymorphism in the gene encoding for mitochondrial cytochrome oxidase b (CytB) and in the ribosomal internal transcribed spacers (ITS1 and ITS2). The three genomic regions revealed sequence differences between the three morphological forms similar in degree to the differences shown previously for members of other anopheline species groups or complexes (genetic distance d = 0.047-0.05 for CytB, 0.084-0.166 for ITS1 and 0.03-0.05 for ITS2). Using sequence variation in the ITS1 region, we set up a diagnostic polymerase chain reaction (PCR) for rapid and reliable identification of each subspecies within the An. moucheti complex. Specimens of An. moucheti s.l. collected in Cameroon, the Democratic Republic of Congo (DRC), Uganda and Nigeria were successfully identified, demonstrating the general applicability of this technique.     

Six new species of the Anopheles leucosphyrus group, reinterpretation of An. elegans and vector implications

Abstract. Among Oriental anopheline mosquitoes (Diptera: Culicidae), several major vectors of forest malaria belong to the group of Anopheles (Cellia) leucosphyrus Dönitz. We have morphologically examined representative material (> 8000 specimens from seven countries) for taxonomic revision of the Leucosphyrus Group. Six new species are here described from adult, pupal and larval stages (with illustrations of immature stages) and formally named as follows: An. latens n. sp. (= An. leucosphyrus species A of Baimai et al., 1988b), An. cracens n. sp., An. scanloni n. sp., An. baimaii n. sp. (formerly An. dirus species B, C, D, respectively), An. mirans n. sp. and An. recens n. sp. Additionally, An. elegans (James) is redescribed and placed in the complex of An. dirus Peyton & Harrison (comprising An. baimaii, An. cracens, An. dirus, An. elegans, An. nemophilous Peyton & Ramalingam, An. scanloni and An. takasagoensis Morishita) of the Leucosphyrus Subgroup, together with An. baisasi Colless and the An. leucosphyrus complex (comprising An. balabacensis Baisas, An. introlatus Baisas, An. latens and An. leucosphyrus). Hence, the former Elegans Subgroup is renamed the Hackeri Subgroup (comprising An. hackeri Edwards, An. pujutensis Colless, An. recens and An. sulawesi Waktoedi). Distribution data and bionomics of the newly defined species are given, based on new material and published records, with discussion of morphological characters for species distinction and implications for ecology and vector roles of such species. Now these and other members of the Leucosphyrus Group are identifiable, it should be possible to clarify the medical importance and distribution of each species. Those already regarded as vectors of human malaria are: An. baimaii[Bangladesh, China (Yunnan), India (Andamans, Assam, Meghalaya, West Bengal), Myanmar, Thailand]; An. latens[Borneo (where it also transmits Bancroftian filariasis), peninsular Malaysia, Thailand]; probably An. cracens (Sumatra, peninsular Malaysia, Thailand); presumably An. scanloni (Thailand); perhaps An. elegans (the Western Ghat form of An. dirus, restricted to peninsular India); but apparently not An. recens (Sumatra) nor An. mirans[Sri Lanka and south-west India (Karnataka, Kerala, Tamil Nadu)], which is a natural vector of simian malarias. Together with typical An. balabacensis, An. dirus and An. leucosphyrus, therefore, the Leucosphyrus Group includes about seven important vectors of forest malaria, plus at least a dozen species of no known medical importance, with differential specific distributions collectively spanning > 5000 km from India to the Philippines.