Papers by Ronildo Alencar
Infection, Genetics and Evolution, Apr 1, 2015
Lutzomyia (Nyssomyia) anduzei has been recognized as a secondary vector of Leishmania guyanensis ... more Lutzomyia (Nyssomyia) anduzei has been recognized as a secondary vector of Leishmania guyanensis in the Brazilian Amazon region. Since L. anduzei is anthropophilic, co-exists in areas of high leishmaniasis transmission and has been found infected with L. guyanensis, the understanding of the vector population structure and of the process responsible for it is paramount to the vector management and control efforts. In this study we analyzed 74 and 67 sequences of the COI and Cytb loci, respectively, from mitochondrial DNA, aiming to estimate the intra-population genetic variability and population structure in six L. anduzei samples from the Brazilian Amazon region. For COI, we found 58 haplotypes, low to high (FST=0.0310-0.4128) and significant (P=0.0033) genetic structure, and reduced gene flow among populations. The haplotype network yielded many reticulations that likely resulted from hypervariability in the locus. For Cytb, we observed 27 haplotypes, low to moderate (FST=0.0077-0.1954) and nonsignificant (P>0.05) genetic structure for the majority of comparisons and extensive gene flow among populations, in line with the haplotypes network data. AMOVA analysis indicated that most of the variation occurred within populations (83.41%, 90.94%); nevertheless, there were significant differences (ΦST=0.0906-0.1659; P=0.00098; P=0.00000) among them for both loci. The Mantel test showed that the genetic structure is not associated to an isolation-by-distance (IBD) model in either of both loci. These data suggest that L. anduzei is genetically very diverse. The genetic structure lacking IBD may be due to adaptation to local habitats and the low dispersal capacity of the sandflies, and both could lead to population fragmentation and geographic isolation. These findings have important implications for epidemiology, surveillance and vector control and may be a first step in understanding the evolutionary history of this species.
PLOS ONE, May 18, 2012
Background: Lutzomyia umbratilis is an important Leishmania guyanensis vector in South America. P... more Background: Lutzomyia umbratilis is an important Leishmania guyanensis vector in South America. Previous studies have suggested differences in the vector competence between L. umbratilis populations situated on opposite banks of the Amazonas and Negro Rivers in the central Amazonian Brazil region, likely indicating a species complex. However, few studies have been performed on these populations and the taxonomic status of L. umbratilis remains unclear. Methodology/Principal Findings: Phylogeographic structure was estimated for six L. umbratilis samples from the central Amazonian region in Brazil by analyzing mtDNA using 1181 bp of the COI gene to assess whether the populations on opposite banks of these rivers consist of incipient or distinct species. The genetic diversity was fairly high and the results revealed two distinct clades (= lineages) with 1% sequence divergence. Clade I consisted of four samples from the left bank of the Amazonas and Negro Rivers, whereas clade II comprised two samples from the right bank of Negro River. No haplotypes were shared between samples of two clades. Samples within clades exhibited low to moderate genetic differentiation (F ST = 20.0390-0.1841), whereas samples between clades exhibited very high differentiation (F ST = 0.7100-0.8497) and fixed differences. These lineages have diverged approximately 0.22 Mya in the middle Pleistocene. Demographic expansion was detected for the lineages I and II approximately 30,448 and 15,859 years ago, respectively, in the late Pleistocene. Conclusions/Significance: The two genetic lineages may represent an advanced speciation stage suggestive of incipient or distinct species within L. umbratilis. These findings suggest that the Amazonas and Negro Rivers may be acting as effective barriers, thus preventing gene flow between populations on opposite sides. Such findings have important implications for epidemiological studies, especially those related to vector competence and anthropophily, and for vector control strategies. In addition, L. umbratilis represents an interesting example in speciation studies.
Figure 2. Anomalousmalesof Pintomyia (Pifanomyia) duckei sp.n. Oliveira,Alencar & Freitas:(a,b) B... more Figure 2. Anomalousmalesof Pintomyia (Pifanomyia) duckei sp.n. Oliveira,Alencar & Freitas:(a,b) Bilateral asymmetricanomaly. Oneof the gonocoxiteswithsixsetae rowed inthebasaltuft. Othergonocoxite withtwobasaltuftsof fiveand sixsetae rowed indicated by arrows, (b=Scheme); (c,d) Unilateral anomaly. Gonocoxites with five and sixsetae in basal tufts indicated by arrows, (d=Scheme).Thisfigure is in color in the electronic version.
Figure 1. Male holotype of Pintomyia (Pifanomyia) duckei sp. n. Oliveira, Alencar & Freitas: (a) ... more Figure 1. Male holotype of Pintomyia (Pifanomyia) duckei sp. n. Oliveira, Alencar & Freitas: (a) Terminalia; (b) Gonostylus in lateral position; (c) Sperm pump and ejaculatory ducts; (d) Head frontal view; (e) Wing; (f) Flagellomere I; (g) Palpal segment III.
Figures S1–S12. in a single web format file. (MHT 7748 kb)
Supplemental spreadsheet. (DOCX 11 kb)
Background: Lutzomyia umbratilis (a probable species complex) is the main vector of Leishmania gu... more 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 matri...
Acta Amazonica, 2018
Pintomyia (Pifanomyia) duckei Oliveira, Alencar and Freitas sp. n. from Adolpho Ducke Reserve, Ma... more Pintomyia (Pifanomyia) duckei Oliveira, Alencar and Freitas sp. n. from Adolpho Ducke Reserve, Manaus, Amazonas state, Brazil, is described and illustrated based on three male specimens, the holotype and two paratypes. The paratypes have abnormalities in the external genitalia, one with asymmetric bilateral anomaly (different anomalies in each of certain paired structures) and the other with unilateral anomaly (anomaly in one of the paired structures). The new species probably belongs to the Serrana Series, integrating the list of the species whose males possess gonostylus with two stout spines (one apical and other subapical), as well as a small and very thin spine on the inner surface of the basal half.
Acta Amazonica, 2015
Phlebotomine sand flies are insects of medical importance. Species in the Neotropical region are ... more Phlebotomine sand flies are insects of medical importance. Species in the Neotropical region are highly diverse. Some of these species are considered cryptic species because of their morphological similarity between adult females of different species make identification especially difficult. The aim of this study was to analyze and describe the armature in the genital atrium (AGA) of some adult female sand flies, in order to discover new taxonomic characters that make it possible to distinguish between species that would otherwise be treated as cryptic by analysis of the AGA. The AGA of 16 Phlebotomine sand fly species are described. Distinct differences were found in relation to the shape and size of the armature, the presence or absence of spines on the armature, and the shape, size, and grouping patterns of the spines. These characters made it possible to distinguish between the species studied.
Acta Tropica, Nov 1, 2018
Details of different polygonal chorionic patterns found in eggs of four Neotropical sandflies spe... more Details of different polygonal chorionic patterns found in eggs of four Neotropical sandflies species: 1) Deanemyia maruaga; 2) Evandromyia walkeri; 3) Nyssomyia antunesi; 4) Viannamyia furcata. Highlights Six species of phlebotomine sandflies had their eggs described for the first time. Placoid is a new chorionic sculpture found in eggs of the Deanemyia samueli. Polygonal pattern is most commonly found in eggs of neotropical sandflies. The same chorionic polygonal pattern may exhibit specific differences. Chorionic characters can be used for taxonomic/systematic studies of sandflies.
Instituto Nacional de Pesquisas da Amazônia, 2003
Informações sobre criadouros naturais de flebotomíneos são escassas, face às dificuldades do isol... more Informações sobre criadouros naturais de flebotomíneos são escassas, face às dificuldades do isolamento dos imaturos do substrato onde se desenvolvem. O presente estudo visou a investigação de criadouros em diversos micro-hábitats numa floresta de terra-firme em Pitinga, Amazonas. Resultados de eficácia das técnicas de extração de imaturos, temperatura, pH, fauna associada, comparação entre as faunas flebotomínicas imaturas e adultas, também são apresentados. Amostras de solo e matéria orgânica de 14 micro-hábitats processadas por quatro técnicas (flotação-peneiramento, exame direto, Berlese-Tullgren, gaiola de incubação) revelaram, pela primeira vez na Amazônia, criadouros naturais em 5 micro-hábitats (base de árvore, chão desabrigado de floresta, solo sob tronco caído, solo sob raiz, base de palmeira), de onde 167 imaturos foram recuperados. Abundância de imaturos em criadouros de bases de árvores foi significativamente maior. Flotação e exame direto foram as técnicas mais eficazes para recuperação de imaturos e emergência de adultos, respectivamente. Armadilha de emergência, outra técnica utilizada neste estudo, rendeu 27 flebotomíneos. Quinze espécies do gênero Lutzomyia foram identificadas, sendo L monstruosa (23,7%) e L georgii (18%) as mais abundantes. Diferenças na composição específica e abundância relativa das faunas flebotomínicas imatura e adulta de bases de árvores sugerem criadouros localizados distantes do local de agregação e/ou repouso dos adultos. O pH, o qual revelou solo de acidez elevada a muito elevada, e a temperatura não apresentaram correlação significativa com o n® de imaturos. A fauna nãoflebotomínica apresentou uma diversidade de artrópodes associados aos criadouros.
Scientific Reports, 2021
Lutzomyia umbratilis is the main vector of Leishmania guyanensis in the Brazilian Amazon and in n... more Lutzomyia umbratilis is the main vector of Leishmania guyanensis in the Brazilian Amazon and in neighboring countries. Previous biological and molecular investigations have revealed significant differences between L. umbratilis populations from the central Brazilian Amazon region. Here, a phylogeographic survey of L. umbratilis populations collected from nine localities in the Brazilian Amazon was conducted using two mitochondrial genes. Statistical analyses focused on population genetics, phylogenetic relationships and species delimitations. COI genetic diversity was very high, whereas Cytb diversity was moderate. COI genealogical haplotypes, population structure and phylogenetic analyses identified a deep genetic differentiation and three main genetic groups. Cytb showed a shallower genetic structure, two main haplogroups and poorly resolved phylogenetic trees. These findings, allied to absence of isolation by distance, support the hypothesis that the Amazon and Negro Rivers and i...
Tables S1–S7. in a single file. (DOCX 35 kb)
Tables S1–S7. in a single file. (DOCX 35 kb)
Acta Amazonica, 2007
Informações acerca de potenciais criadouros naturais de flebotomíneos sempre foram de fundamental... more Informações acerca de potenciais criadouros naturais de flebotomíneos sempre foram de fundamental interesse epidemiológico. Contudo, são poucas as informações advindas dos diversos estudos realizados até o momento. Isto se deve principalmente às dificuldades de localização e extração dos imaturos que se desenvolvem no solo e matéria orgânica do chão de florestas. No presente estudo o modelo modificado de armadilha de emergência foi testado na Vila do Pitinga, município de Presidente Figueiredo, Estado do Amazonas, a fim de localizar potenciais criadouros naturais. Vinte e sete indivíduos de nove espécies (Lutzomyia umbratilis,L. monstruosa,L. ayrozai,L. anduzei,L. trichopyga,L. davisi,L. geniculata,L. georgii e L. saulensis) foram coletados. Lutzomyia umbratilis foi a espécie com maior número de indivíduos, 10, representando 37,1% do total. A produção de flebotomíneos foi estimada em 2,2 flebotomíneos por 100 m² por dia. Em setembro, mês com maior número de indivíduos, esta produção...
Background: Lutzomyia umbratilis is an important Leishmania guyanensis vector in South America. P... more Background: Lutzomyia umbratilis is an important Leishmania guyanensis vector in South America. Previous studies have suggested differences in the vector competence between L. umbratilis populations situated on opposite banks of the Amazonas and Negro Rivers in the central Amazonian Brazil region, likely indicating a species complex. However, few studies have been performed on these populations and the taxonomic status of L. umbratilis remains unclear. Methodology/Principal Findings: Phylogeographic structure was estimated for six L. umbratilis samples from the central Amazonian region in Brazil by analyzing mtDNA using 1181 bp of the COI gene to assess whether the populations on opposite banks of these rivers consist of incipient or distinct species. The genetic diversity was fairly high and the results revealed two distinct clades ( = lineages) with 1 % sequence divergence. Clade I consisted of four samples from the left bank of the Amazonas and Negro Rivers, whereas clade II comp...
FIGURE 8. Numerical chaetotaxy and hook-like spines in anal division of fourth-instar larvae of N... more FIGURE 8. Numerical chaetotaxy and hook-like spines in anal division of fourth-instar larvae of Notofairchildia stenygros. Abbreviation: IS = intersegmental seta.
FIGURE 7. Schematic drawing of fourth-instar larval stage of Notofairchildia stenygros in dorsal,... more FIGURE 7. Schematic drawing of fourth-instar larval stage of Notofairchildia stenygros in dorsal, lateral and ventral view, showing the numeric chaetotaxy and highlighting the brush-like seta, the simple grouped setae (pedichaetes) and the brush-like setae in transversal cut showing the carinas. Abbreviations: an. = antenna; A.D. = anal division; a.sp. = abdominal spiracle; ca. = cardo; cs = caudal setae; hy = hypostoma; hy.b. = hypostomal bridge; hy.ph. = hypopharynx; lb = labrum; IS = intersegmental seta; md. = mandibule; mx. = maxillae; s,ca. = subcardo; t.sp. = thoracic spiracle.
FIGURE 6. Mouthparts of fourth-instar larva of Notofairchildia stenygros: A, maxilla and mandible... more FIGURE 6. Mouthparts of fourth-instar larva of Notofairchildia stenygros: A, maxilla and mandible in lateral external view; B, maxillae in lateral internal view; C, labium-hypopharynx in lateral view; D, premental sclerite and suspensorium of the hypopharynx in dorsal view. Abbreviations: ca = cardo; ga = galea; glo = glossa; hy = hypostoma; hy.ph. = hypopharynx; hy.s. = suspensorium of hypopharynx; lc = lacinia; l.p. = labial palp; md = mandible; me. = mentum; mx.p. = maxillary palp; pl. = palpifer; pm.s. = premental sclerite; s.ca. = subcardo; st. = stipes.
FIGURE 5. Scanning electron microscopy of some structures of the fourth-instar larval stages and ... more FIGURE 5. Scanning electron microscopy of some structures of the fourth-instar larval stages and pupa of Notofairchildia stenygros: A, caudal setae, scale = 50 µm; B, anal division (in the rectangle tiny hooks of the anus), scale = 50 µm; C, hook-like spines of the lower edge of the anus (arrows), scale = 10 µm; D, pedichaetes, scale = 10 µm; E, full pupa in lateral view, scale = 500 µm; F, head and thorax of the pupa in ventral view, scale = 100 µm. Abbreviations: an. = antenna; lg. = leg; pa. = palp; r.o. = respiratory organ.
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Papers by Ronildo Alencar