Phylogenomics reveals the history of host use in mosquitoes.

Mosquitoes have profoundly affected human history and continue to threaten human health through the transmission of a diverse array of pathogens. The phylogeny of mosquitoes has remained poorly characterized due to difficulty in taxonomic sampling and limited availability of genomic data beyond the most important vector species. Here, we used phylogenomic analysis of 709 single copy ortholog groups from 256 mosquito species to produce a strongly supported phylogeny that resolves the position of the major disease vector species and the major mosquito lineages. Our analyses support an origin of mosquitoes in the early Triassic (217 MYA [highest posterior density region: 188-250 MYA]), considerably older than previous estimates. Moreover, we utilize an extensive database of host associations for mosquitoes to show that mosquitoes have shifted to feeding upon the blood of mammals numerous times, and that mosquito diversification and host-use patterns within major lineages appear to coincide in earth history both with major continental drift events and with the diversification of vertebrate classes.

Insights from a comprehensive study of Trypanosoma cruzi: A new mitochondrial clade restricted to North and Central America and genetic structure of TcI in the region.

More than 100 years since the first description of Chagas Disease and with over 29,000 new cases annually due to vector transmission (in 2010), American Trypanosomiasis remains a Neglected Tropical Disease (NTD). This study presents the most comprehensive Trypanosoma cruzi sampling in terms of geographic locations and triatomine species analyzed to date and includes both nuclear and mitochondrial genomes. This addresses the gap of information from North and Central America. We incorporate new and previously published DNA sequence data from two mitochondrial genes, Cytochrome oxidase II (COII) and NADH dehydrogenase subunit 1 (ND1). These T. cruzi samples were collected over a broad geographic range including 111 parasite DNA samples extracted from triatomines newly collected across North and Central America, all of which were infected with T. cruzi in their natural environment. In addition, we present parasite reduced representation (Restriction site Associated DNA markers, RAD-tag) genomic nuclear data combined with the mitochondrial gene sequences for a subset of the triatomines (27 specimens) collected from Guatemala and El Salvador. Our mitochondrial phylogenetic reconstruction revealed two of the major mitochondrial lineages circulating across North and Central America, as well as the first ever mitochondrial data for TcBat from a triatomine collected in Central America. Our data also show that within mtTcIII, North and Central America represent an independent, distinct clade from South America, named here as mtTcIIINA-CA, geographically restricted to North and Central America. Lastly, the most frequent lineage detected across North and Central America, mtTcI, was also an independent, distinct clade from South America, noted as mtTcINA-CA. Furthermore, nuclear genome data based on Single Nucleotide Polymorphism (SNP) showed genetic structure of lineage TcI from specimens collected in Guatemala and El Salvador supporting the hypothesis that genetic diversity at a local scale has a geographical component. Our multiscale analysis contributes to the understanding of the independent and distinct evolution of T. cruzi lineages in North and Central America regions.

Belminus santosmalletae (Hemiptera: Heteroptera: Reduviidae): New Species from Panama, with an Updated Key for Belminus Stål, 1859 Species.

Belminus santosmalletae, a new triatomine species, is described based on a specimen from Panama, deposited in the collection of the National Museum of Natural History (NMNH), Smithsonian Institution, Washington, DC, USA. Attempts failed to identify this specimen using the keys by Lent and Wygodzinsky (1979) and Sandoval et al. (2007). A comparison was made with specimens of Belminus Stål, 1859 specimens deposited at the Triatominae collection at the Oswaldo Cruz Institute (CTIOC), Rio de Janeiro, Brazil; and with previous descriptions of Belminus species. These comparisons showed the specimen represents a new species, described in the present paper. It differs from other species of the genus mainly by the grainy tegument, scarce pilosity along the body, and the number of tubercles observed on the pronotum.

Formal Assignation of the Kissing Bug Triatoma lecticularia (Hemiptera: Reduviidae: Triatominae) to the Genus Paratriatoma.

The subfamily Triatominae (Hemiptera: Reduviidae) comprises hematophagous insects that are vectors of Chagas disease; including species assigned to the genera Triatoma and Paratriatoma. Initial examination of Triatoma lecticularia revealed the hirsuteness covering the entire body-a characteristic and striking feature of members of the genus Paratriatoma-and a systematic study revealed several other morphological characters that are in diagnostic alignment with Paratriatoma. Based on the examination of several specimens (including the lectotype), and with the additional support of molecular and cytogenetic data, we propose the formal transferal of Triatoma lecticularia (Stål, 1859) into the genus Paratriatoma with the resulting new combination: Paratriatoma lecticularia (Stål, 1859) comb. nov. (Hemiptera: Reduviidae: Triatominae).

Designation of the neotype of Triatomadimidiata (Latreille, 1811) (Hemiptera, Reduviidae, Triatominae), with full integrated redescription including mitogenome and nuclear ITS-2 sequences.

The taxonomic status of Triatomadimidiata (Latreille, 1811) is, by far, the most discussed within Triatominae. Molecular studies have recovered at least three independently evolving lineages in T.dimidiata across its range. The original description of T.dimidiata (as Reduviusdimidiatus) included few taxonomic characters, and no types were assigned. To define and describe the cryptic diversity within T.dimidiata sensu lato (s.l.), a neotype must be designated. For this purpose, all 199 specimens identified as T.dimidiata from the collections of the Smithsonian Institution - National Museum of Natural History and the American Museum of Natural History, ranging from Peru to Mexico, were studied. Only one specimen (from Tumbes, Peru) matched the combination of characters as listed in the original description, and it is herein formally designated as the neotype for T.dimidiata. The neotype is morphologically described and DNA sequences of its whole mitochondrial genome and the nuclear second internal transcribed spacer region (ITS2), commonly used in triatomine molecular systematics studies, are presented and compared to other publicly available sequences of T.dimidiata s.l. in GenBank. Our results suggest that T.dimidiata sensu stricto (s.s.) is somewhat rare and, therefore, unlikely to serve as a major vector of Chagas disease.

Description of a new species of Nesotriatoma Usinger, 1944 from Cuba and revalidation of synonymy between Nesotriatoma bruneri (Usinger, 1944) and N. flavida (Neiva, 1911) (Hemiptera, Reduviidae, Triatominae).

Nesotriatoma confusa sp. nov. (Hemiptera, Reduviidae, Triatominae) is described based on specimens from Cuba. From one male, one female, and eleven nymphs of a then-undescribed species of Nesotriatoma collected in Cuba, a colony was formed and its specimens were used to describe N. confusa sp. nov. Characters were observed on the head, thorax, abdomen, female external genitalia, and male genitalia with optical microscopy and scanning electron microscopy. We concluded that N. bruneri (Usinger, ) was indeed a synonym of N. flavida (Neiva, ) as previously proposed.

DNA barcoding does not separate South American Triatoma (Hemiptera: Reduviidae), Chagas Disease vectors.

BACKGROUND: DNA barcoding assumes that a biological entity is completely separated from its closest relatives by a barcoding gap, which means that intraspecific genetic distance (from COI sequences) should never be greater than interspecific distances. We investigated the applicability of this strategy in identifying species of the genus Triatoma from South America. FINDINGS: We calculated intra and interspecific Kimura-2-parameter distances between species from the infestans, matogrossensis, sordida and rubrovaria subcomplexes. In every subcomplex examined we observed at least one intraspecific distance greater than interspecific distances. CONCLUSIONS: Although DNA barcoding is a straightforward approach, it was not applicable for identifying Southern American Triatoma species, which may have diverged recently. Thus, caution should be taken in identifying vector species using this approach, especially in groups where accurate identification of taxa is fundamentally linked to public health issues.

Molecular phylogeny of Triatomini (Hemiptera: Reduviidae: Triatominae).

BACKGROUND: The Triatomini and Rhodniini (Hemiptera: Reduviidae) tribes include the most diverse Chagas disease vectors; however, the phylogenetic relationships within the tribes remain obscure. This study provides the most comprehensive phylogeny of Triatomini reported to date. METHODS: The relationships between all of the Triatomini genera and representatives of the three Rhodniini species groups were examined in a novel molecular phylogenetic analysis based on the following six molecular markers: the mitochondrial 16S; Cytochrome Oxidase I and II (COI and COII) and Cytochrome B (Cyt B); and the nuclear 18S and 28S. RESULTS: Our results show that the Rhodnius prolixus and R. pictipes groups are more closely related to each other than to the R. pallescens group. For Triatomini, we demonstrate that the large complexes within the paraphyletic Triatoma genus are closely associated with their geographical distribution. Additionally, we observe that the divergence within the spinolai and flavida complex clades are higher than in the other Triatoma complexes. CONCLUSIONS: We propose that the spinolai and flavida complexes should be ranked under the genera Mepraia and Nesotriatoma. Finally, we conclude that a thorough morphological investigation of the paraphyletic genera Triatoma and Panstrongylus is required to accurately assign queries to natural genera.

Sistemática molecular e importância epidemiológica de Rhodnius spp. (Hemiptera: Rudiviidae) na Bolívia / Molecular systematics and epidemiological importance of Rhodnius spp. (Hemiptera: Rudiviidae) in Bolivia

A doença de Chagas, conseqüência da infecção pelo protozoário flagelado Trypanosoma cruzi, afeta hoje cerca de 15 milhões de pessoas, enquanto que aproximadamente 70 a 90 milhões vivem sob o risco de contraí-la. Na Bolívia, 60 a 80% do território é considerado endêmico e estima-se que 28% da população está infectada. Neste país a transmissão vetorial é mediada principalmente por Triatoma infestans, sabidamente capaz de colonizar domicílios. Devido à presença de populações silvestres de T. infestans em quatro dos nove departamentos da Bolívia e à sua grande importância epidemiológica, estudos sobre outras espécies vetoras de Chagas presentes no país foram negligenciados e, por isso, pouco se sabe acerca de seus papéis na transmissão da doença. Nessa dissertação foram estudadas populações do gênero Rhodnius (acerca do qual existem contradições com relação à presença de algumas espécies naquele país), objetivando-se (1) determinar o status taxonômico dos espécimes encontrados (já que as espécies que lá ocorrem pertencem a grupos de espécies morfologicamente muito semelhantes ou indistinguíveis), utilizando a taxonomia molecular a partir do seqüenciamento de um fragmento de 682pb do gene mitocondrial citocromo b (cit b) e do segundo espaçador ribossomal interno transcrito (ITS-2); (2) definir os ecótopos naturais das espécies encontradas; (3) estudar a genética populacional das espécies; e (4) inferir a possível importância epidemiológica de cada espécie encontrada, realizando diagnósticos moleculares por PCR para obtenção das taxas de infecção natural por T. cruzi. Foi obtido um total de 102 espécimes, provenientes de 10 localidades distribuídas nos departamentos de La Paz, Cochabamba, Santa Cruz e Beni. A partir da taxonomia molecular, foi possível identificar que as espécies coletadas foram Rhodnius stali e Rhodnius robustus II. As análises de polimorfismo de cit b revelaram uma baixa diversidade haplotípica intraespecífica. Não foi possível estudar a estruturação das populações de R. stali, devido ao baixo número de amostras. Os 84 espécimes de R. robustus II coletados pertencem a quatro populações altamente estruturadas. A partir das genealogias moleculares construídas para essa espécie foi possível criar duas hipóteses de dispersão, em que ambas indicaram a origem boliviana de R. robustus II. A observação dos estudos ecológicos e epidemiológicos permitiu concluir que existem duas situações opostas nas regiões do Alto Beni (La Paz) e do departamento de Santa Cruz. Na primeira, onde R. stali está domiciliado, foi possível determinar seu ecótopo silvestre, até então desconhecido, como sendo a palmeira Attalea phalerata; além disso, dos 12 espécimes coletados (todos em palmeiras) apenas um estava infectado. Em Santa Cruz, dos 69 espécimes obtidos (55 de peridomicílio, 11 coletados no intradomicílio e 3 no ambiente silvestre) mais de 40% estavam infectados. Interessantemente, nenhum dos 15 insetos coletados no ambiente silvestre (Cochabamba e Concepción, em Santa Cruz) estava infectado.