Lineage divergence detected in the malaria vector Anopheles marajoara (Diptera: Culicidae) in Amazonian Brazil

Population Genetic Structure of Phlebotomus sergenti (Diptera: Psychodidae) Collected in Four Regions of Morocco Based on the Analysis of Cyt b and EF-1α Genes

Phlebotomus (Ph.) sergenti is the main vector of Leishmania (L.) tropica (Trypanosomatida: Trypanosomatidae), the causative agent of anthroponotic cutaneous leishmaniasis in Morocco. This species has an extended geographical distribution, wider than that of the parasite. The main objective of our study was to analyze the genetic diversity of Ph. sergenti collected in four foci in Morocco: Taza, Foum Jemâa, El Hanchane, and Ouarzazate. We studied a set of diversity and population structure indices by sequencing two markers; nuclear EF-1α and mitochondrial Cyt b from 175 individual sand flies. Our results showed a considerable degree of intraspecific polymorphism with a high number of haplotypes identified in both genes. Many polymorphic sites detected in the Cyt b sequences (SCyt b = 45) indicate that it is the most polymorphic marker showing a distinct distribution of haplotypes according to their geographical origin, whereas the EF-1α marker showed no geographical isolation. Analysis by Tajima's D and Fu's Fs tests revealed a possible recent expansion of the populations, especially with the EF-1α marker, showing significant values in Taza and Ouarzazate sequences. The present study revealed significant genetic diversity within Ph. sergenti populations in Morocco. The results warrant further research using a combination of more than two markers including mitochondrial and non-mitochondrial markers, which may provide more information to clarify the genetic status of Ph. sergenti.

Phylogenetic analysis of the Neotropical Albitarsis Complex based on mitogenome data

BACKGROUND

Some of the most important malaria vectors in South America belong to the Albitarsis Complex (Culicidae; Anophelinae; Anopheles). Understanding the origin, nature, and geographical distribution of species diversity in this important complex has important implications for vector incrimination, control, and management, and for modelling future responses to climate change, deforestation, and human population expansion. This study attempts to further explore species diversity and evolutionary history in the Albitarsis Complex by undertaking a characterization and phylogenetic analysis of the mitogenome of all 10 putative taxa in the Albitarsis Complex.

METHODS

Mitogenome assembly and annotation allowed for feature comparison among Albitarsis Complex and Anopheles species. Selection analysis was conducted across all 13 protein-coding genes. Maximum likelihood and Bayesian inference methods were used to construct gene and species trees, respectively. Bayesian methods were also used to jointly estimate species delimitation and species trees.

RESULTS

Gene composition and order were conserved across species within the complex. Unique signatures of positive selection were detected in two species-Anopheles janconnae and An. albitarsis G-which may have played a role in the recent and rapid diversification of the complex. The COI gene phylogeny does not fully recover the mitogenome phylogeny, and a multispecies coalescent-based phylogeny shows that considerable uncertainty exists through much of the mitogenome species tree. The origin of divergence in the complex dates to the Pliocene/Pleistocene boundary, and divergence within the distinct northern South American clade is estimated at approximately 1 million years ago. Neither the phylogenetic trees nor the delimitation approach rejected the 10-species hypothesis, although the analyses could not exclude the possibility that four putative species with scant a priori support (An. albitarsis G, An. albitarsis H, An. albitarsis I, and An. albitarsis J), represent population-level, rather than species-level, splits.

CONCLUSION

The lack of resolution in much of the species tree and the limitations of the delimitation analysis warrant future studies on the complex using genome-wide data and the inclusion of additional specimens, particularly from two putative species, An. albitarsis I and An. albitarsis J.

Updating the bionomy and geographical distribution of Anopheles (Nyssorhynchus) albitarsis F: A vector of malaria parasites in northern South America

Anopheles albitarsis F is a putative species belonging to the Albitarsis Complex, recognized by rDNA, mtDNA, partial white gene, and microsatellites sequences. It has been reported from the island of Trinidad, Venezuela and Colombia, and incriminated as a vector of malaria parasites in the latter. This study examined mitochondrially encoded cytochrome c oxidase I (MT-CO1) sequences of An. albitarsis F from malaria-endemic areas in Colombia and Venezuela to understand its relations with other members of the Complex, revised and update the geographical distribution and bionomics of An. albitarsis F and explore hypotheses to explain its phylogenetic relationships and geographical expansion. Forty-five MT-CO1 sequences obtained in this study were analyzed to estimate genetic diversity and possible evolutionary relationships. Sequences generated 37 haplotypes clustered in a group where the genetic divergence of Venezuelan populations did not exceed 1.6% with respect to Colombian samples. Anopheles albitarsis F (π = 0.013) represented the most recent cluster located closer to An. albitarsis I (π = 0.009). Barcode gap was detected according to Albitarsis Complex lineages previously reported (threshold 0.014–0.021). Anopheles albitarsis F has a wide distribution in northern South America and might play an important role in the transmission dynamics of malaria due to its high expansion capacity. Future studies are required to establish the southern distribution of An. albitarsis F in Venezuela, and its occurrence in Guyana and Ecuador.

Phylogenetic Network of Mitochondrial COI Gene Sequences Distinguishes 10 Taxa Within the Neotropical Albitarsis Group (Diptera: Culicidae), Confirming the Separate Species Status of Anopheles albitarsis H (Diptera: Culicidae) and Revealing a Novel Lineage, Anopheles albitarsis J

The Neotropical Albitarsis Group is a complex assemblage of essentially isomorphic species which currently comprises eight recognized species-five formally described (Anopheles albitarsis Lynch-Arribalzaga, An. deaneorum Rosa-Freitas, An. janconnae Wilkerson and Sallum, An. marajoara Galvao and Damasceno, An. oryzalimnetes Wilkerson and Motoki) and three molecularly assigned (An. albitarsis F, G & I)-and one mitochondrial lineage (An. albitarsis H). To further explore species recognition within this important group, 658 base pairs of the mitochondrial DNA cytochrome oxidase subunit I (COI) were analyzed from 988 specimens from South America. We conducted statistical parsimony network analysis, generated estimates of haplotype, nucleotide, genetic differentiation, divergence time, and tested the effect of isolation by distance (IBD). Ten clusters were identified, which confirmed the validity of the eight previously determined species, and confirmed the specific status of the previous mitochondrial lineage An. albitarsis H. High levels of diversity were highlighted in two samples from Pará (= An. albitarsis J), which needs further exploration through additional sampling, but which may indicate another cryptic species. The highest intra-specific nucleotide diversity was observed in An. deaneorum, and the lowest in An. marajoara. Significant correlation between genetic and geographical distance was observed only in An. oryzalimnetes and An. albitarsis F. Divergence time within the Albitarsis Group was estimated at 0.58-2.25 Mya, during the Pleistocene. The COI barcode region was considered an effective marker for species recognition within the Albitarsis Group and a network approach was an analytical method to discriminate among species of this group.

Genetic diversity and population structure of Anopheles triannulatus s. l. in the department of Córdoba, Colombia, using DNA barcoding

Introduction: Anopheles triannulatus is not incriminated as a vector of malaria transmission in Colombia despite recent reports of infection with Plasmodium spp. in populations related to the northwestern and southeastern lineages. Genetic diversity can delimit information about gene flow and population differentiation in localities with malaria. Objective: To estimate the genetic diversity of An. triannulatus in five municipalities with high and low incidence of malaria in the department of Córdoba. Materials and methods: The entomological collections were done between August and November, 2016, in Tierralta, Puerto Libertador, Montelíbano, Sahagún, and Planeta Rica. We used the COI barcoding fragment as molecular marker. The genetic analysis included the estimation of genetic parameters such as the diversity haplotype, the genetic structure, the gene flow, the Tajima’s D test, the haplotype network, and the phylogenetic relationship. Results: We obtained 148 sequences with a length of 655 nucleotides of the COI gene, from which we derived 44 haplotypes. The H2 and H21 haplotypes were the most frequent in the populations. The values of the Tajima’s D test were negative and not significant (p>0.10). The genetic structure index (FST=0.01427) and the gene flow (Nm=17.27) evidenced no differentiation between sampled populations due to the high exchange of migrants. Using phylogenetic inferences and the haplotype network, we identified one single species without geographic differentiation or lineages in the geographic range studied. Conclusions: The genetic diversity calculated for An. triannulatus in this context indicated stable populations in constant exchange.

Discrimination of Anopheles species of the Arribalzagia Series in Colombia using a multilocus approach

The Arribalzagia Series of the Anopheles Subgenus comprises morphologically similar species or members of species complexes which makes correct species identification difficult. Therefore, the aim of this work was to discriminate the morphospecies of the Arribalzagia Series present in Colombia using a multilocus approach based on ITS2, COI and CAD sequences. Specimens of the Arribalzagia Series collected at 32 localities in nine departments were allocated to seven species. Individual and concatenated Bayesian analyses showed high support for each of the species and reinforced the previous report of the Apicimacula species Complex with distribution in the Pacific Coast and northwestern Colombia. In addition, a new molecular operational taxonomic unit-MOTU was identified, herein denominated near Anopheles peryassui, providing support for the existence of a Peryassui species Complex. Further, the CAD gene, just recently used for Anopheles taxonomy and phylogeny, demonstrated its power in resolving phylogenetic relationships among species of the Arribalzagia Series. The divergence times for these species correspond to the early Pliocene and the Miocene. Considering the epidemiological importance of some species of the Series and their co-occurrence in malaria endemic regions of Colombia, their discrimination constitutes an important step for vector incrimination and control in the country.

Molecular taxonomy and evolutionary relationships in the Oswaldoi-Konderi complex (Anophelinae: Anopheles: Nyssorhynchus) from the Brazilian Amazon region

Recent studies have shown that Anopheles oswaldoi sensu lato comprises a cryptic species complex in South America. Anopheles konderi, which was previously raised to synonymy with An. oswaldoi, has also been suggested to form a species complex. An. oswaldoi has been incriminated as a malaria vector in some areas of the Brazilian Amazon, Colombia, Peru and Venezuela, but was not recognized as a vector in the remaining regions in its geographic distribution. The role of An. konderi as a malaria vector is unknown or has been misattributed to An. oswaldoi. The focus of this study was molecular identification to infer the evolutionary relationships and preliminarily delimit the geographic distribution of the members of these complexes in the Brazilian Amazon region. The specimens were sampled from 18 localities belonging to five states in the Brazilian Amazon and sequenced for two molecular markers: the DNA barcode region (COI gene of mitochondrial DNA) and Internal Transcribed Spacer 2 (ITS2 ribosomal DNA). COI (83 sequences) and ITS2 (27 sequences) datasets generated 43 and 10 haplotypes, respectively. Haplotype networks and phylogenetic analyses generated with the barcode region (COI gene) recovered five groups corresponding to An. oswaldoi s.s., An. oswaldoi B, An. oswaldoi A, An. konderi and An. sp. nr. konderi; all pairwise genetic distances were greater than 3%. The group represented by An. oswaldoi A exhibited three strongly supported lineages. The molecular dating indicated that the diversification process in these complexes started approximately 2.8 Mya, in the Pliocene. These findings confirm five very closely related species and present new records for these species in the Brazilian Amazon region. The paraphyly observed for the An. oswaldoi complex suggests that An. oswaldoi and An. konderi complexes may comprise a unique species complex named Oswaldoi-Konderi. Anopheles oswaldoi B may be a potential malaria vector in the extreme north of the Brazilian Amazon, whereas evidence of sympatry for the remaining species in other parts of the Brazilian Amazon (Acre, Amazonas, Pará and Rondônia) precluded identification of probable vectors in those areas.

Evidence of new species for malaria vector Anopheles nuneztovari sensu lato in the Brazilian Amazon region

BACKGROUND

Anopheles nuneztovari sensu lato comprises cryptic species in northern South America, and the Brazilian populations encompass distinct genetic lineages within the Brazilian Amazon region. This study investigated, based on two molecular markers, whether these lineages might actually deserve species status.

METHODS

Specimens were collected in five localities of the Brazilian Amazon, including Manaus, Careiro Castanho and Autazes, in the State of Amazonas; Tucuruí, in the State of Pará; and Abacate da Pedreira, in the State of Amapá, and analysed for the COI gene (Barcode region) and 12 microsatellite loci. Phylogenetic analyses were performed using the maximum likelihood (ML) approach. Intra and inter samples genetic diversity were estimated using population genetics analyses, and the genetic groups were identified by means of the ML, Bayesian and factorial correspondence analyses and the Bayesian analysis of population structure.

RESULTS

The Barcode region dataset (N = 103) generated 27 haplotypes. The haplotype network suggested three lineages. The ML tree retrieved five monophyletic groups. Group I clustered all specimens from Manaus and Careiro Castanho, the majority of Autazes and a few from Abacate da Pedreira. Group II clustered most of the specimens from Abacate da Pedreira and a few from Autazes and Tucuruí. Group III clustered only specimens from Tucuruí (lineage III), strongly supported (97 %). Groups IV and V clustered specimens of A. nuneztovari s.s. and A. dunhami, strongly (98 %) and weakly (70 %) supported, respectively. In the second phylogenetic analysis, the sequences from GenBank, identified as A. goeldii, clustered to groups I and II, but not to group III. Genetic distances (Kimura-2 parameters) among the groups ranged from 1.60 % (between I and II) to 2.32 % (between I and III). Microsatellite data revealed very high intra-population genetic variability. Genetic distances showed the highest and significant values (P = 0.005) between Tucuruí and all the other samples, and between Abacate da Pedreira and all the other samples. Genetic distances, Bayesian (Structure and BAPS) analyses and FCA suggested three distinct biological groups, supporting the barcode region results.

CONCLUSIONS

The two markers revealed three genetic lineages for A. nuneztovari s.l. in the Brazilian Amazon region. Lineages I and II may represent genetically distinct groups or species within A. goeldii. Lineage III may represent a new species, distinct from the A. goeldii group, and may be the most ancestral in the Brazilian Amazon. They may have differences in Plasmodium susceptibility and should therefore be investigated further.

Molecular taxonomy provides new insights into anopheles species of the neotropical arribalzagia series

Phylogenetic analysis of partial mitochondrial cytochrome oxidase c subunit I (COI) and nuclear internal transcribed spacer 2 (ITS2) sequences were used to evaluate initial identification and to investigate phylogenetic relationships of seven Anopheles morphospecies of the Arribalzagia Series from Colombia. Phylogenetic trees recovered highly supported clades for An. punctimaculas.s., An. calderoni, An. malefactor s.l., An. neomaculipalpus, An. apicimacula s.l., An. mattogrossensis and An. peryassui. This study provides the first molecular confirmation of An. malefactorfrom Colombia and discovered conflicting patterns of divergence for the molecular markers among specimens from northeast and northern Colombia suggesting the presence of two previously unrecognized Molecular Operational Taxonomic Units (MOTUs). Furthermore, two highly differentiated An. apicimacula MOTUs previously found in Panama were detected. Overall, the combined molecular dataset facilitated the detection of known and new Colombian evolutionary lineages, and constitutes the baseline for future research on their bionomics, ecology and potential role as malaria vectors.

Barcoding Turkish Culex mosquitoes to facilitate arbovirus vector incrimination studies reveals hidden diversity and new potential vectors

As a precursor to planned arboviral vector incrimination studies, an integrated systematics approach was adopted using morphology and DNA barcoding to examine the Culex fauna present in Turkey. The mitochondrial COI gene (658bp) were sequenced from 185 specimens collected across 11 Turkish provinces, as well as from colony material. Although by morphology only 9 species were recognised, DNA barcoding recovered 13 distinct species including: Cx. (Barraudius) modestus, Cx. (Culex) laticinctus, Cx. (Cux.) mimeticus, Cx. (Cux.) perexiguus, Cx. (Cux.) pipiens, Cx. (Cux.) pipiens form molestus, Cx. (Cux.) quinquefasciatus, Cx. (Cux.) theileri, Cx. (Cux.) torrentium, Cx. (Cux.) tritaeniorhynchus and Cx. (Maillotia) hortensis. The taxon formerly identified as Cx. (Neoculex) territans was shown to comprise two distinct species, neither of which correspond to Cx. territans s.s. These include Cx. (Neo.) impudicus and another uncertain species, which may be Cx. (Neo.) europaeus or Cx. (Neo.) martinii (herein=Cx. (Neo.) sp. 1). Detailed examination of the Pipiens Group revealed Cx. pipiens, Cx. pipiens f. molestus and the widespread presence of the highly efficient West Nile virus vector Cx. quinquefasciatus for the first time. Four new country records are reported, increasing the Culex of Turkey to 15 recognised species and Cx. pipiens f. molestus. A new taxonomic checklist is provided, annotated with respective vector competencies for transmission of arboviruses.

High morphological and genetic variabilities of Ochlerotatus scapularis, a potential vector of filarias and arboviruses

Background

Ochlerotatus scapularis is a potential vector of filarias and arboviruses in the Neotropics. This species was once typically associated with sylvatic environments; however, cases of synanthropy and urbanization of this species have been increasingly reported in southeast Brazil. Despite the medical relevance of Oc. scapularis, its populational variability is not yet known. To our knowledge, this is the first report describing the morphological and genetic variabilities of this species.

Methods

Population samples were characterized using the cytochrome oxidase subunit I (COI) mitochondrial gene and wing geometrics. Adult mosquitoes were collected from five sampling sites from remnants of the Atlantic forest embedded in the urban or rural areas of southeast Brazil.

Results

In the 130 individuals analyzed, 46 COI haplotypes were detected. Haplotype diversity was high and ranged from 0.66 to 0.97. Six haplotypes were present in 61% of the individuals, whereas the remaining haplotypes were less frequent (39%). Wing shape was also highly polymorphic. Differentiation of populations across sampling sites according to genetic distances (F_st = −0.009 to 0.060) and morphological distances (Q_st = 0.47) indicated that populations were not identical. No correlations were noted for phenetic and genetic diversities (p = 0.19) or for genetic or phenetic distances with geographical distances (p = 0.2 and p = 0.18, respectively).

Conclusions

Our study results suggest that Oc. scapularis has a rich genetic patrimony, even though its habitat is fragmented. Implications of such genetic richness with respect to vectorial competence, plasticity, and ability to exploit urbanized areas need to be further investigated.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-0740-6) contains supplementary material, which is available to authorized users.

Hybrid sterility in crosses between two Brazilian sibling species of the Anopheles albitarsis complex

Background

Complexes of cryptic species are common in several taxa and this is also the case in the Anopheles genus, a group including all known human malaria vectors. The Anopheles albitarsis complex comprises at least nine cryptic species, some of which are implicated as vectors of human malaria. Several different types of data have been generated for this species complex such as cytogenetics, alloenzymes, morphological and feeding behavioral, hybridization experiments, RAPD-PCR and RFLP and mitochondrial and nuclear markers. Studies focused on its postzygotic isolation are still somewhat rare in the literature despite their importance to understand the speciation process and the level of gene flow potentially occurring among the different sibling species.

Methods

Hybridization experiments between Anopheles albitarsis s.s. and Anopheles marajoara, as well as backcrosses between hybrids and Anopheles albitarsis s.s., were performed using the induced mating technique. Results were compared to intraspecific crosses. Larva-to-adult viability and sex ratio were also assessed.

Results

Male hybrids show very low insemination rates and nearly complete sterility, apparently due to abnormalities in their reproductive organs. Evidence of partial sterility among the hybrid females was also observed.

Conclusions

Our data indicated that Anopheles albitarsis s.s. and Anopheles marajoara show a high level of postzygotic isolation with a strong hybrid male sterility. This result is consistent with the Haldane’s rule which states that in interspecific crosses the heterogametic sex is the first to be affected. However, the fact that the females are not completely sterile raises the possibility of introgression between these two siblings species.

Demographic history and population structure of Anopheles pseudopunctipennis in Argentina based on the mitochondrial COI gene

Background

Anopheles pseudopunctipennis is an important malaria vector in the Neotropical region and the only species involved in Plasmodium transmission in the Andean foothills. Its wide geographical distribution in America, high preference for biting humans and capacity to rest inside dwellings after feeding, are attributes contributing to its vector status. Previous reports have tried to elucidate its taxonomic status, distinguishing populations from North, Central and South America. In the present study we used a mitochondrial marker to examine the demographic history of An. pseudopunctipennis in northwestern Argentina.

Methods

Twelve localities were selected across 550 km of the distribution of this species in Argentina, including two near the Bolivian border and several in South Tucumán, for sampling. A fragment of the cytochrome oxidase I (COI) gene was sequenced and haplotype relationships were analyzed by a statistical parsimony network and a Neighbor-Joining (NJ) tree. Genetic differentiation was estimated with F_ST. Historical demographic processes were evaluated using diversity measures, neutrality tests and mismatch distribution.

Results

Forty-one haplotypes were identified, of which haplotype A was the most common and widely distributed. Neither the network nor the NJ tree showed any geographic differentiation between northern and southern populations. Haplotype diversities, Tajima’s D_T and Fu & Li’s F and D neutrality tests and mismatch distribution supported a scenario of Holocene demographic expansion.

Conclusion

The demographic pattern suggests that An. pseudopunctipennis has undergone a single colonization process, and the ancestral haplotype is shared by specimens from all localities, indicating mitochondrial gene flow. Genetic differentiation was minimal, observed only between one northern and one southern locality. The estimated time of the population expansion of this species was during the Holocene. These data suggest that regional vector control measures would be equally effective in both northern and southern localities sampled, but also that insecticide resistant genes may spread rapidly within this region.

Molecular taxonomy of the two Leishmania vectors Lutzomyia umbratilis and Lutzomyia anduzei (Diptera: Psychodidae) from the Brazilian Amazon

BACKGROUND

Lutzomyia umbratilis (a probable species complex) is the main vector of Leishmania guyanensis in the northern region of Brazil. Lutzomyia anduzei has been implicated as a secondary vector of this parasite. These species are closely related and exhibit high morphological similarity in the adult stage; therefore, they have been wrongly identified, both in the past and in the present. This shows the need for employing integrated taxonomy.

METHODS

With the aim of gathering information on the molecular taxonomy and evolutionary relationships of these two vectors, 118 sequences of 663 base pairs (barcode region of the mitochondrial DNA cytochrome oxidase I - COI) were generated from 72 L. umbratilis and 46 L. anduzei individuals captured, respectively, in six and five localities of the Brazilian Amazon. The efficiency of the barcode region to differentiate the L. umbratilis lineages I and II was also evaluated. The data were analyzed using the pairwise genetic distances matrix and the Neighbor-Joining (NJ) tree, both based on the Kimura Two Parameter (K2P) evolutionary model.

RESULTS

The analyses resulted in 67 haplotypes: 32 for L. umbratilis and 35 for L. anduzei. The mean intra-specific genetic distance was 0.008 (0.002 to 0.010 for L. umbratilis; 0.008 to 0.014 for L. anduzei), whereas the mean interspecific genetic distance was 0.044 (0.041 to 0.046), supporting the barcoding gap. Between the L. umbratilis lineages I and II, it was 0.009 to 0.010. The NJ tree analysis strongly supported monophyletic clades for both L. umbratilis and L. anduzei, whereas the L. umbratilis lineages I and II formed two poorly supported monophyletic subclades.

CONCLUSIONS

The barcode region clearly separated the two species and may therefore constitute a valuable tool in the identification of the sand fly vectors of Leishmania in endemic leishmaniasis areas. However, the barcode region had not enough power to separate the two lineages of L. umbratilis, likely reflecting incipient species that have not yet reached the status of distinct species.

The distribution of the Phlebotomus major complex (Diptera: Psychodidae) in Turkey

The taxonomic status and distribution of the morphologically similar members of the Phlebotomus major complex in Turkey are unclear. To examine the utility of traditional morphological characters and molecular markers, sand flies were sampled from 90 localities in eleven different provinces covering a wide geographical range throughout Turkey. The morphometric variability was analysed using multivariate analyses of twelve characters, while mitochondrial cytochrome b (Cyt b) and nuclear elongation factor 1α (EF 1-α) genes were used for molecular discrimination. Three distinct monophyletic lineages were identified based on the phylogenetic analysis of the combined data set of mitochondrial and nuclear gene regions, which were also supported by parsimony haplotype network analysis and AMOVA of Cyt b. The first lineage is restricted to south eastern Turkey and represents the species Phlebotomus syriacus, the second is present mostly in the westernmost and the easternmost localities and represents P. neglectus, and the third member of this complex is distributed across the mid-northern and mid-southern regions. None of the studied morphological characters were found to be sufficient to discriminate between these three members of the P. major s.l. complex; however their presence sympatrically in several localities supports their status as species rather than inter-population variability.

Wing geometric morphometrics and molecular assessment of members in the Albitarsis Complex from Colombia

Malaria parasites are transmitted to humans by female mosquitoes of the genus Anopheles. The Albitarsis Complex harbours at least eight species not readily differentiable by morphology. This complicates the determination of those species involved in malaria transmission and the implementation of targeted and effective vector control strategies. In Colombia, there is little information about the identity and distribution of the Albitarsis Complex members. In this work, COI DNA barcoding was used to assign specimens Anopheles albitarsis s.l. to any of the previously designated species of the Albitarsis Complex. Two molecular operational taxonomic units (MOTUs), differentially distributed in Colombia, were detected, A. albitarsis I in the NW and NE, and A. albitarsis F, E and NE Colombia. In contrast, nuclear white gene and ITS2 sequence analyses did not allow differentiating between the MOTUs. Wing landmark-based geometric morphometrics applied to explore intertaxa phenotypic heterogeneity showed a subtle but significant difference in size, while shape did not allow the separation of the MOTUs. In general, the multiple marker analysis was not supportive of the existence in Colombia of more than one species of the Albitarsis Complex.

Biological and molecular characterization of Hessian fly (Diptera: Cecidomyiidae) from Israel

Samples of a dipteran pest of wheat were tested to confirm identity, describe local populations and suggest the use of deploying resistance (R) genes in wheat cultivars for control of Mayetiola destructor, Hessian fly (HF). Morphological evaluation of adults and a free-choice oviposition preference test documenting that females overwhelmingly preferred to oviposit on wheat instead of barley supported they were HF. Using the cytochrome c oxidase subunit I (coxI), the Barcoding Region, nine haplotypes were revealed. Two were found only in the Israeli collections and averaged 3% sequence divergence compared to the other seven haplotypes found in the United States, Israel and Syria. In evaluations of virulence, the Israeli HF in culture was virulent to 11 of the 19 (R) genes tested, and complementation analysis documented that, for four of the R genes tested, the Israeli HF shared loci for virulence with HF from the United States. Levels of HF infestation at seven Israeli fields were at least at the 5-8% level, which historically has indicated a significant yield loss. Microsatellite genotyping of the five HF collections from Israel revealed mixed populations in Israel that are distinctly separate from the single population in Syria.

Genetic diversity of Anopheles triannulatus s.l. (Diptera: Culicidae) from northwestern and southeastern Colombia

Anopheles triannulatus s.l. is a species complex, however in Colombia its taxonomic status is unclear. This study was conducted to understand the level of genetic differentiation or population structure of specimens of An. triannulatus s.l. from northwestern and southeastern Colombia. Cytochrome oxidase subunit I (COI) and internal transcribed spacer (ITS2) sequence analyses suggested high genetic differentiation between the NW and SE populations. A TCS network and Bayesian inference analysis based on 814 bp of COI showed two main groups: group I included samples from the NW and group II samples from the SE. Two main ITS2-polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) patterns were found. Pattern I is present in both the NW and SE, and pattern II is found in the SE specimens. To further elucidate the taxonomic status of An. triannulatus s.l. in Colombia and how these COI lineages are related to the Triannulatus Complex species, the evaluation of immature stages, male genitalia, and additional mitochondrial and nuclear markers will be needed.

DNA barcoding reveals both known and novel taxa in the Albitarsis Group (Anopheles: Nyssorhynchus) of Neotropical malaria vectors

Background

Mosquitoes belonging to the Albitarsis Group (Anopheles: Nyssorhynchus) are of importance as malaria vectors across the Neotropics. The Group currently comprises six known species, and recent studies have indicated further hidden biodiversity within the Group. DNA barcoding has been proposed as a highly useful tool for species recognition, although its discriminatory utility has not been verified in closely related taxa across a wide geographic distribution.

Methods

DNA barcodes (658 bp of the mtDNA Cytochrome c Oxidase - COI) were generated for 565 An. albitarsis s.l. collected in Argentina, Brazil, Colombia, Paraguay, Trinidad and Venezuela over the past twenty years, including specimens from type series and type localities. Here we test the utility of currently advocated barcoding methodologies, including the Kimura-two-parameter distance model (K2P) and Neighbor-joining analysis (NJ), for determining species delineation within mosquitoes of the Neotropical Albitarsis Group of malaria vectors (Anopheles: Nyssorhynchus), and compare results with Bayesian analysis.

Results

Species delineation through barcoding analysis and Bayesian phylogenetic analysis, fully concur. Analysis of 565 sequences (302 unique haplotypes) resolved nine NJ tree clusters, with less than 2% intra-node variation. Mean intra-specific variation (K2P) was 0.009 (range 0.002 - 0.014), whereas mean inter-specific divergence were several-fold higher at 0.041 (0.020 - 0.056), supporting the reported "barcoding gap". These results show full support for separate species status of the six known species in the Albitarsis Group (An. albitarsis s.s., An. albitarsis F, An. deaneorum, An. janconnae, An. marajoara and An. oryzalimnetes), and also support species level status for two previously detected lineages - An. albitarsis G &An. albitarsis I (designated herein). In addition, we highlight the presence of a unique mitochondrial lineage close to An. deaneorum and An. marajoara (An. albitarsis H) from Rondônia and Mato Grosso in southwestern Brazil. Further integrated studies are required to confirm the status of this lineage.

Conclusions

DNA barcoding provides a reliable means of identifying both known and undiscovered biodiversity within the closely related taxa of the Albitarsis Group. We advocate its usage in future studies to elucidate the vector competence and respective distributions of all eight species in the Albitarsis Group and the novel mitochondrial lineage (An. albitarsis H) recovered in this study.

DNA barcoding of recently diverged species: relative performance of matching methods

Recently diverged species are challenging for identification, yet they are frequently of special interest scientifically as well as from a regulatory perspective. DNA barcoding has proven instrumental in species identification, especially in insects and vertebrates, but for the identification of recently diverged species it has been reported to be problematic in some cases. Problems are mostly due to incomplete lineage sorting or simply lack of a 'barcode gap' and probably related to large effective population size and/or low mutation rate. Our objective was to compare six methods in their ability to correctly identify recently diverged species with DNA barcodes: neighbor joining and parsimony (both tree-based), nearest neighbor and BLAST (similarity-based), and the diagnostic methods DNA-BAR, and BLOG. We analyzed simulated data assuming three different effective population sizes as well as three selected empirical data sets from published studies. Results show, as expected, that success rates are significantly lower for recently diverged species (∼75%) than for older species (∼97%) (P<0.00001). Similarity-based and diagnostic methods significantly outperform tree-based methods, when applied to simulated DNA barcode data (P<0.00001). The diagnostic method BLOG had highest correct query identification rate based on simulated (86.2%) as well as empirical data (93.1%), indicating that it is a consistently better method overall. Another advantage of BLOG is that it offers species-level information that can be used outside the realm of DNA barcoding, for instance in species description or molecular detection assays. Even though we can confirm that identification success based on DNA barcoding is generally high in our data, recently diverged species remain difficult to identify. Nevertheless, our results contribute to improved solutions for their accurate identification.

Mitochondrial DNA detects a complex evolutionary history with Pleistocene Epoch divergence for the neotropical malaria vector Anopheles nuneztovari sensu lato

Cryptic species and lineages characterize Anopheles nuneztovari s.l. Gabaldón, an important malaria vector in South America. We investigated the phylogeographic structure across the range of this species with cytochrome oxidase subunit I (COI) mitochondrial DNA sequences to estimate the number of clades and levels of divergence. Bayesian and maximum-likelihood phylogenetic analyses detected four groups distributed in two major monophyletic clades (I and II). Samples from the Amazon Basin were clustered in clade I, as were subclades II-A and II-B, whereas those from Bolivia/Colombia/Venezuela were restricted to one basal subclade (II-C). These data, together with a statistical parsimony network, confirm results of previous studies that An. nuneztovari is a species complex consisting of at least two cryptic taxa, one occurring in Colombia and Venezuela and the another occurring in the Amazon Basin. These data also suggest that additional incipient species may exist in the Amazon Basin. Divergence time and expansion tests suggested that these groups separated and expanded in the Pleistocene Epoch. In addition, the COI sequences clearly separated An. nuneztovari s.l. from the closely related species An. dunhami Causey, and three new records are reported for An. dunhami in Amazonian Brazil. These findings are relevant for vector control programs in areas where both species occur. Our analyses support dynamic geologic and landscape changes in northern South America, and infer particularly active divergence during the Pleistocene Epoch for New World anophelines.

Analysis of the evolutionary forces shaping mitochondrial genomes of a Neotropical malaria vector complex

Many vectors of human malaria belong to complexes of morphologically indistinguishable cryptic species. Here we report the analysis of the newly sequenced complete mitochondrial DNA molecules from six recognized or putative species of one such group, the Neotropical Anopheles albitarsis complex. The molecular evolution of these genomes had been driven by purifying selection, particularly strongly acting on the RNA genes. Directional mutation pressure associated with the strand-asynchronous asymmetric mtDNA replication mechanism may have shaped a pronounced DNA strand asymmetry in the nucleotide composition in these and other Anopheles species. The distribution of sequence polymorphism, coupled with the conflicting phylogenetic trees inferred from the mitochondrial DNA and from the published white gene fragment sequences, indicates that the evolution of the complex may have involved ancient mtDNA introgression. Six protein coding genes (nad5, nad4, cox3, atp6, cox1 and nad2) have high levels of sequence divergence and are likely informative for population genetics studies. Finally, the extent of the mitochondrial DNA variation within the complex supports the notion that the complex consists of a larger number of species than until recently believed.