1
|
Carbajal-de-la-Fuente AL, Piccinali RV, Porcasi X, Marti GA, de Arias AR, Abrahan L, Suárez FC, Lobbia P, Medina G, Provecho Y, Cortez MR, Soria N, Gonçalves TC, Nattero J. Variety is the spice: The role of morphological variation of Triatoma infestans (Hemiptera, Reduviidae) at a macro-scale. Acta Trop 2024; 256:107239. [PMID: 38735448 DOI: 10.1016/j.actatropica.2024.107239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/14/2024]
Abstract
Chagas disease is caused by the protozoan parasite Trypanosoma cruzi (Chagas, 1909). One of the primary vectors of T. cruzi in South America is Triatoma infestans (Klug, 1834). This triatomine species is distributed across a huge latitudinal gradient, inhabiting domiciliary , peridomiciliary , and wild environments. Its wide geographic distribution provides an excellent opportunity to study the relationships between environmental gradients and intraspecific morphological variation. In this study, we investigated variations in wing size and shape in T. infestans across six ecoregions. We aimed to address the following questions: How do wing size and shape vary on a regional scale, does morphological variation follow specific patterns along an environmental or latitudinal gradient, and what environmental factors might contribute to wing variation? Geometric morphometric methods were applied to the wings of 162 females belonging to 21 T. infestans populations, 13 from Argentina (n = 105), 5 from Bolivia (n = 42), and 3 from Paraguay (n = 15). A comparison of wing centroid size across the 21 populations showed significant differences. Canonical Variate Analysis (CVA) revealed significant differences in wing shape between the populations from Argentina, Bolivia, and Paraguay, although there was a considerable overlap, especially among the Argentinian populations. Well-structured populations were observed for the Bolivian and Paraguayan groups. Two analyses were performed to assess the association between wing size and shape, geographic and climatic variables: multiple linear regression analysis (MRA) for size and Partial Least Squares (PLS) regression for shape. The MRA showed a significant general model fit. Six temperature-related variables, one precipitation-related variable, and the latitude showed significant associations with wing size. The PLS analysis revealed a significant correlation between wing shape with latitude, longitude, temperature-related, and rainfall-related variables. Wing size and shape in T. infestans populations varied across geographic distribution. Our findings demonstrate that geographic and climatic variables significantly influence T. infestans wing morphology.
Collapse
Affiliation(s)
- Ana Laura Carbajal-de-la-Fuente
- Centro Nacional de Diagnóstico e Investigación en Endemo-epidemias (CENDIE/ ANLIS-Malbrán). Av. Paseo Colón 568, CP 1063, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, CP 1425, Ciudad Autónoma de Buenos Aires, Argentina.
| | - Romina V Piccinali
- Laboratorio de Eco-Epidemiología, DEGE (FCEN, UBA), IEGEBA (UBA/CONICET), Intendente Güiraldes 2160 - Ciudad Universitaria - Pabellón 2, CP 1428, Ciudad Autónoma de Buenos Aires, Argentina
| | - Ximena Porcasi
- Instituto Gulich (CONAE UNC), Ruta C45 Km 8, CP 5187, Falda del Cañete, Córdoba, Argentina
| | - Gerardo Aníbal Marti
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE) CCT-La Plata CONICET-UNLP-asociado a CIC, Blvd. 120 y 60 CP 1900, La Plata, Buenos Aires, Argentina
| | - Antonieta Rojas de Arias
- Centro para el Desarrollo de la Investigación Científica (CEDIC), Manduvirá 635 entre 15 de agosto y Oleary, CP 1255, Asunción, Paraguay
| | - Luciana Abrahan
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR), UNLAR, SEGEMAR, UNCa, CONICET, Entre Ríos y Mendoza s/n, Anillaco, CP 5301, La Rioja, Provincia de La Rioja, Argentina
| | - Florencia Cano Suárez
- Programa Provincial Control de Vectores, Ministerio de Salud Pública San Juan. Santa Fe 977 (este) predio Hospital Dr Guillermo Rawson, CP 5400, San Juan, Argentina
| | - Patricia Lobbia
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, CP 1425, Ciudad Autónoma de Buenos Aires, Argentina; Unidad Operativa de Vectores y Ambiente (UNOVE), Centro Nacional de Diagnóstico e Investigación en Endemo-epidemias (CENDIE / ANLIS-Malbrán), Pabellón Rawson s/n. Hospital Colonia, CP 2423, Santa María de Punilla, Córdoba, Argentina
| | - Gabriela Medina
- Dirección de Control Integral de Vectores y Zoonosis. Laboratorio Entomológico y Parasitológico. Ministerio de Salud de Catamarca, Chacabuco 169, CP 4700, San Fernando del Valle de Catamarca, Argentina
| | - Yael Provecho
- Ministerio de Salud de la Nación, Dirección de Control de Enfermedades Transmitidas por Vectores. Av. 9 de Julio 1925, CP 1073, Ciudad Autónoma de Buenos Aires, Argentina
| | - Mirko Rojas Cortez
- Fundación Salud Naturaleza Integral (SANIT), Pasaje Fidelia de Sanchez 433, CP 00591, Cochabamba, Bolivia
| | - Nicolás Soria
- División Manejo Integrado de Vectores, Departamento de Zoonosis, Dirección de Jurisdicción de Epidemiología, Ministerio de Salud de la Provincia de Córdoba, Santiago Cáceres 1885, CP 5000, Córdoba, Argentina
| | - Teresa C Gonçalves
- Laboratório Interdisciplinar de Vigilância Entomológica em Diptera e Hemiptera. Instituto Oswaldo Cruz (IOC/ Fundação Oswaldo Cruz). Av. Brasil, 4365, Manguinhos, CP 21040-360, Rio de Janeiro, Brasil
| | - Julieta Nattero
- Laboratorio de Eco-Epidemiología, DEGE (FCEN, UBA), IEGEBA (UBA/CONICET), Intendente Güiraldes 2160 - Ciudad Universitaria - Pabellón 2, CP 1428, Ciudad Autónoma de Buenos Aires, Argentina
| |
Collapse
|
2
|
Cruz DD, Ospina-Garces SM, Arellano E, Ibarra-Cerdeña CN, Nava-García E, Alcalá R. Geometric morphometrics and ecological niche modelling for delimitation of Triatoma pallidipennis (Hemiptera: Reduviidae: Triatominae) haplogroups. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2023; 3:100119. [PMID: 37009555 PMCID: PMC10064238 DOI: 10.1016/j.crpvbd.2023.100119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/27/2023] [Accepted: 03/07/2023] [Indexed: 03/17/2023]
Abstract
A recent phylogenetic analysis of Triatoma pallidipennis, an important Chagas disease vector in Mexico, based on molecular markers, revealed five monophyletic haplogroups with validity as cryptic species. Here, we compare T. pallidipennis haplogroups using head and pronotum features, environmental characteristics of their habitats, and ecological niche modeling. To analyze variation in shape, images of the head and pronotum of the specimens were obtained and analyzed using methods based on landmarks and semi-landmarks. Ecological niche models were obtained from occurrence data, as well as a set of bioclimatic variables that characterized the environmental niche of each analyzed haplogroup. Deformation grids for head showed a slight displacement towards posterior region of pre-ocular landmarks. Greatest change in head shape was observed with strong displacement towards anterior region of antenniferous tubercle. Procrustes ANOVA and pairwise comparisons showed differences in mean head shape in almost all haplogroups. However, pairwise comparisons of mean pronotum shape only showed differences among three haplogroups. Correct classification of all haplogroups was not possible using discriminant analysis. Important differences were found among the environmental niches of the analyzed haplogroups. Ecological niche models of each haplogroup did not predict the climatic suitability areas of the other haplogroups, revealing differences in environmental conditions. Significant differences were found between at least two haplogroups, demonstrating distinct environmental preferences among them. Our results show how the analysis of morphometric variation and the characterization of the environmental conditions that define the climatic niche can be used to improve the delimitation of T. pallidipennis haplogroups that constitute cryptic species.
Collapse
|
3
|
Belintani T, Oliveira J, Pinotti H, Silva LA, Alevi KCC, Galvão C, Rosa JAD. Phylogenetic and phenotypic relationships of the Triatoma sordida subcomplex (Hemiptera: Reduviidae: Triatominae). Acta Trop 2020; 212:105679. [PMID: 32860747 DOI: 10.1016/j.actatropica.2020.105679] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 11/29/2022]
Abstract
Chagas disease, whose etiological agent is the protozoan Trypanosoma cruzi, affects millions of people worldwide and it is mainly transmitted by infected triatomine feces. Triatoma is the most diverse genus and one of the most important from an epidemiological point of view. Species of this genus are grouped into eight complexes and nine subcomplexes. Triatoma sordida subcomplex consists of T. garciabesi, T. guasayana, T. patagonica, and, T. sordida. Given the recent discussions on their phylogenetic status, this study aims to evaluate morphometric and genetics characters that group and distinguish T. garciabesi, T. guasayana, T. patagonica, and T. sordida, as well as to infer the phylogenetic relationships within the group and evaluate the proximity with T. rubrovaria subcomplex. The results corroborate the phylogenetic relationship of T. guasayana and T. patagonica with the T. rubrovaria subcomplex. Molecular data confirm the proximity of T. jurbergi, T. matogrossensis, T. vandae as T. garciabesi, and T. sordida. Together, genetic variability was shown between T. sordida populations.
Collapse
Affiliation(s)
- Tiago Belintani
- Institute of Biology, Campinas State University (Unicamp), Block O, Bertrand Russel Avenue, Campinas, São Paulo 13083-865, Brazil..
| | - Jader Oliveira
- São Paulo State University (Unesp), School of Pharmaceutical Sciences, Araraquara-Jaú Highway, km 1, Campos Ville, Araraquara, São Paulo 14800-903, Brazil
| | - Heloisa Pinotti
- São Paulo State University (Unesp), School of Pharmaceutical Sciences, Araraquara-Jaú Highway, km 1, Campos Ville, Araraquara, São Paulo 14800-903, Brazil
| | - Lucas Abrantes Silva
- São Paulo State University (Unesp), School of Pharmaceutical Sciences, Araraquara-Jaú Highway, km 1, Campos Ville, Araraquara, São Paulo 14800-903, Brazil
| | - Kaio Cesar Chaboli Alevi
- São Paulo State University (Unesp), School of Pharmaceutical Sciences, Araraquara-Jaú Highway, km 1, Campos Ville, Araraquara, São Paulo 14800-903, Brazil
| | - Cleber Galvão
- Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - João Aristeu da Rosa
- Institute of Biology, Campinas State University (Unicamp), Block O, Bertrand Russel Avenue, Campinas, São Paulo 13083-865, Brazil.; São Paulo State University (Unesp), School of Pharmaceutical Sciences, Araraquara-Jaú Highway, km 1, Campos Ville, Araraquara, São Paulo 14800-903, Brazil
| |
Collapse
|
4
|
Identifying Chagas disease vectors using elliptic Fourier descriptors of body contour: a case for the cryptic dimidiata complex. Parasit Vectors 2020; 13:332. [PMID: 32611375 PMCID: PMC7329423 DOI: 10.1186/s13071-020-04202-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/20/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Triatoma dimidiata (Reduviidae: Triatominae) is an important vector of Chagas disease in various countries in the Americas. Phylogenetic studies have defined three lineages in Mexico and part of Central America. While there is a marked genetic differentiation, methods for identifying them using morphometric analyses with landmarks have not yet been fully resolutive. Elliptical Fourier descriptors (EFDs), which mathematically describe the shape of any closed two-dimensional contours, could be a potentially useful alternative method. Our objective was to validate the use of EFDs for the identification of three lineages of this species complex. METHOD A total of 84 dorsal view images of individuals of the three lineages were used. Body contours were described with EFDs using between 5 and 30 harmonics. The number of obtained coefficients was reduced by a principal components analysis and the first axis scores were used as shape variables. A linear discriminant function analysis and an ordination plot of the discriminant analysis were performed using the shape variables. A confusion matrix of the ordination plot of the discriminant analysis was obtained to estimate the classification errors, the first five PC scores were statistically compared, and a neural network were then performed using the shape variables. RESULTS The first principal component explained 50% of the variability, regardless the number of harmonics used. The results of discriminant analysis get improved by increasing the number of harmonics and components considered. With 25 harmonics and 30 components, the identification of haplogroups was achieved with an overall efficiency greater than 97%. The ordering diagram showed the correct discrimination of haplogroups, with only one error of discrimination corroborated by the confusion matrix. When comparing the first five PC scores, significant differences were found among at least two haplogroups. The 30 multilayer perceptron neural networks were also efficient in identification, reaching 91% efficiency with the validation data. CONCLUSIONS The use of EFD is a simple and useful method for the identification of the main lineages of Triatoma dimidiata, with high values of correct identification.
Collapse
|
5
|
Prinsloo ND, Postma M, de Bruyn PJN. How unique is unique? Quantifying geometric differences in stripe patterns of Cape mountain zebra, Equus zebra zebra (Perissodactyla: Equidae). Zool J Linn Soc 2020. [DOI: 10.1093/zoolinnean/zlaa036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Quantified coat pattern dissimilarity provides a visible surface for individual animal traceability to populations. We determined the feasibility in quantifying uniqueness of stripe patterns of Cape mountain zebra (CMZ; Equus zebra zebra) using geometric morphometrics. We photogrammetrically created dense surface models of CMZ (N = 56). Stripe edges were landmarked, superimposed and compared for shape variation across replicates and the population. Significant allometry in stripe patterns prompted allometric correction to remove increased curvature of stripes at the rump, belly and back with larger adult individuals, to facilitate equilibrated comparison between individuals. Re-landmarked replicates showed lower dissimilarity (Di) than non-replicates (Dp), representing minimal landmarking error. Individuals were 78.07 ± 1.79% unique (U=1−DiDp×100%) relative to the study population. Size, the number of torso stripes and degree of branching in four rear torso stripes described the most shape variation (36.79%) but a significant portion could only be distinguished with geometric morphometrics (41.82%). This is the first known use of geometric morphometrics to quantify coat pattern uniqueness, using a model species to provide baseline individual morphological variation. Measures of coat pattern similarity have a place in phenotypic monitoring and identification.
Collapse
Affiliation(s)
- Nicolas D Prinsloo
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Martin Postma
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - P J Nico de Bruyn
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| |
Collapse
|
6
|
Madeira FF, dos Reis YV, Bittinelli IDF, Delgado LMG, de Oliveira J, Mendonça VJ, Moreira FFF, de Azeredo-Oliveira MTV, da Rosa JA, Alevi KCC. Genetic Structure of Brazilian Populations of Triatoma sordida (Stål, 1859) (Hemiptera, Triatominae) by Means of Chromosomal Markers. Am J Trop Med Hyg 2019; 100:907-910. [PMID: 30793692 PMCID: PMC6447125 DOI: 10.4269/ajtmh.18-0336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 11/07/2018] [Indexed: 11/07/2022] Open
Abstract
Triatoma sordida is among the main Brazilian species considered as Chagas disease vectors. The genetic studies are directed mainly to phylogenetic questions because this species possibly have suffered cryptic speciation. Furthermore, there are few studies that analyzed the structure and genetic variability of specimens from Brazil and that showed low genetic diversity and strong genetic structuring of the population samples. Therefore, because of great epidemiological importance of T. sordida and mainly the restriction of genetic characterization of this vector only for populations of Minas Gerais state, this article performs a genetic analysis of the T. sordida from seven different Brazilian states (representing different biomes), by means of cytogenetic markers. All analyzed specimens presents the same cytogenetic characteristics: early meiotic prophase with several heterochromatic bodies dispersed in the nucleus (CG-rich), being one of them formed by the associated sex chromosomes surrounded by some autosomal heterochromatic regions, meiotic metaphase with most autosomal pairs exhibiting a C-heterochromatic block in one chromosomal end (CG-rich), Y sex chromosome fully heterochromatin (AT-rich), and X chromosome may present a small C-block (CG-rich). These results are important because the chromosomal markers enable to confirm and expand the low genetic diversity for all Brazilian states occupied by T. sordida, suggesting that all Brazilian populations were originated from a small ancestral population and possibly dispersed to other biomes by founder effect. In addition, we suggest that T. sordida from Brazil are not suffering cryptic speciation and we confirm the classification of all Brazilian examples as T. sordida sensu stricto.
Collapse
Affiliation(s)
- Fernanda Fernandez Madeira
- Laboratório de Biologia Celular, Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (IBILCE/UNESP), São José do Rio Preto, Brazil
| | - Yago Visinho dos Reis
- Laboratório de Biologia Celular, Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (IBILCE/UNESP), São José do Rio Preto, Brazil
| | - Isadora de Freitas Bittinelli
- Laboratório de Biologia Celular, Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (IBILCE/UNESP), São José do Rio Preto, Brazil
- Laboratório de Parasitologia, Departamento de Ciências Biológicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (FCFAR/UNESP), Araraquara, Brazil
| | - Luiza Maria Grzyb Delgado
- Laboratório de Biologia Celular, Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (IBILCE/UNESP), São José do Rio Preto, Brazil
| | - Jader de Oliveira
- Laboratório de Parasitologia, Departamento de Ciências Biológicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (FCFAR/UNESP), Araraquara, Brazil
| | - Vagner José Mendonça
- Departamento de Parasitologia e Microbiologia, Centro de Ciências da Saúde, Universidade Federal do Piauí (UFPI), Teresina, Brazil
| | | | - Maria Tercília Vilela de Azeredo-Oliveira
- Laboratório de Biologia Celular, Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (IBILCE/UNESP), São José do Rio Preto, Brazil
| | - João Aristeu da Rosa
- Laboratório de Parasitologia, Departamento de Ciências Biológicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (FCFAR/UNESP), Araraquara, Brazil
| | - Kaio Cesar Chaboli Alevi
- Laboratório de Parasitologia, Departamento de Ciências Biológicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista “Júlio de Mesquita Filho” (FCFAR/UNESP), Araraquara, Brazil
| |
Collapse
|
7
|
de Carvalho GC, Vendrami DP, Marrelli MT, Wilke ABB. Wing variation in Culex nigripalpus (Diptera: Culicidae) in urban parks. Parasit Vectors 2017; 10:423. [PMID: 28923116 PMCID: PMC5604421 DOI: 10.1186/s13071-017-2348-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/28/2017] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Culex nigripalpus has a wide geographical distribution and is found in North and South America. Females are considered primary vectors for several arboviruses, including Saint Louis encephalitis virus, Venezuelan equine encephalitis virus and Eastern equine encephalitis virus, as well as a potential vector of West Nile virus. In view of the epidemiological importance of this mosquito and its high abundance, this study sought to investigate wing variation in Cx. nigripalpus populations from urban parks in the city of São Paulo, Brazil. METHODS Female mosquitoes were collected in seven urban parks in the city of São Paulo between 2011 and 2013. Eighteen landmark coordinates from the right wing of each female mosquito were digitized, and the dissimilarities between populations were assessed by canonical variate analysis and cross-validated reclassification and by constructing a Neighbor-Joining (NJ) tree based on Mahalanobis distances. The centroid size was calculated to determine mean wing size in each population. RESULTS Canonical variate analysis based on fixed landmarks of the wing revealed a pattern of segregation between urban and sylvatic Cx. nigripalpus, a similar result to that revealed by the NJ tree topology, in which the population from Shangrilá Park segregated into a distinct branch separate from the other more urban populations. CONCLUSION Environmental heterogeneity may be affecting the wing shape variation of Cx. nigripalpus populations.
Collapse
Affiliation(s)
| | | | - Mauro Toledo Marrelli
- Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, Brazil.,Instituto de Medicina Tropical, Universidade de São Paulo, São Paulo, Brazil
| | | |
Collapse
|
8
|
Nattero J, Piccinali RV, Macedo Lopes C, Hernández ML, Abrahan L, Lobbia PA, Rodríguez CS, Carbajal de la Fuente AL. Morphometric variability among the species of the Sordida subcomplex (Hemiptera: Reduviidae: Triatominae): evidence for differentiation across the distribution range of Triatoma sordida. Parasit Vectors 2017; 10:412. [PMID: 28877741 PMCID: PMC5585980 DOI: 10.1186/s13071-017-2350-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/29/2017] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The Sordida subcomplex (Triatominae) comprises four species, Triatoma garciabesi, T. guasayana, T. patagonica and T. sordida, which differ in epidemiological importance and adaptations to human environments. Some morphological similarities among species make taxonomic identification, population differentiation and species delimitation controversial. Triatoma garciabesi and T. sordida are the most similar species, having been considered alternatively two and a single species until T. garciabesi was re-validated, mostly based on the morphology of male genitalia. More recently, T. sordida from Argentina has been proposed as a new cryptic species distinguishable from T. sordida from Brazil, Bolivia and Paraguay by cytogenetics. We studied linear and geometric morphometry of the head, wings and pronotum in populations of these species aiming to find phenotypic markers for their discrimination, especially between T. sordida and T. garciabesi, and if any set of variables that validates T. sordida from Argentina as a new species. RESULTS Head width and pronotum length were the linear variables that best differentiated species. Geometric morphometry revealed significant Mahalanobis distances in wing shape between all pairwise comparisons. Triatoma patagonica exhibited the best discrimination and T. garciabesi overlapped the distribution of the other species in the morphometric space of the first two DFA axes. Head shape showed differentiation between all pairs of species except for T. garciabesi and T. sordida. Pronotum shape did not differentiate T. garciabesi from T. guasayana. The comparison between T. garciabesi and T. sordida from Argentina and T. sordida from Brazil and Bolivia revealed low differentiation based on head and pronotum linear measurements. Pronotum and wing shape were different between T. garciabesi and T. sordida from Brazil and Bolivia and T. sordida from Argentina. Head shape did not differentiate T. garciabesi from T. sordida from Argentina. CONCLUSIONS Wing shape best delimited the four species phenotypically. The proposed cryptic species, T. sordida from Argentina, differed from T. sordida from Brazil and Bolivia in all measured shape traits, suggesting that the putative new species may not be cryptic. Additional studies integrating cytogenetic, phenotypic and molecular markers, as well as cross-breeding experiments are needed to confirm if these three entities represent true biological species.
Collapse
Affiliation(s)
- Julieta Nattero
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución/Laboratorio de Eco-Epidemiología, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
- CONICET - Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Romina Valeria Piccinali
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución/Laboratorio de Eco-Epidemiología, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
- CONICET - Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Catarina Macedo Lopes
- Laboratório Interdisciplinar de Vigilância Entomológica em Diptera e Hemiptera- Instituto Oswaldo Cruz, Avenida Brasil, 4365, Manguinhos, Rio de Janeiro, 21040-900 Brazil
| | - María Laura Hernández
- Centro Regional de Investigaciones Científicas y de Transferencia Tecnológica de La Rioja (CRILAR-CONICET), Entre Ríos y Mendoza s/n, 5301 La Rioja, Argentina
| | - Luciana Abrahan
- Centro Regional de Investigaciones Científicas y de Transferencia Tecnológica de La Rioja (CRILAR-CONICET), Entre Ríos y Mendoza s/n, 5301 La Rioja, Argentina
| | - Patricia Alejandra Lobbia
- Centro de Referencia de Vectores, Ministerio de Salud de la Nación, Hospital Colonia, Pabellón Rawson calle s/n, X5164 Santa María de Punilla, Córdoba Argentina
| | - Claudia Susana Rodríguez
- Intituto de Investigaciones Biológicas y Tecnológicas, CONICET, FCEFyN, UNC, Avenida Vélez Sarsfield 299, X5000JJC Córdoba, Argentina
| | - Ana Laura Carbajal de la Fuente
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución/Laboratorio de Eco-Epidemiología, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
- CONICET - Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| |
Collapse
|