title: Hypothesis testing clarifies the systematics of the main Central American Chagas disease vector, Triatoma dimidiata (Latreille, 1811), across its geographic range.
abstract: The widespread and diverse Triatoma dimidiata is the kissing bug species most important for Chagas disease transmission in Central America and a secondary vector in Mexico and northern South America. Its diversity may contribute to different Chagas disease prevalence in different localities and has led to conflicting systematic hypotheses describing various populations as subspecies or cryptic species. To resolve these conflicting hypotheses, we sequenced a nuclear (internal transcribed spacer 2, ITS-2) and mitochondrial gene (cytochrome b) from an extensive sampling of T. dimidiata across its geographic range. We evaluated the congruence of ITS-2 and cyt b phylogenies and tested the support for the previously proposed subspecies (inferred from ITS-2) by: (1) overlaying the ITS-2 subspecies assignments on a cyt b tree and, (2) assessing the statistical support for a cyt b topology constrained by the subspecies hypothesis. Unconstrained phylogenies inferred from ITS-2 and cyt b are congruent and reveal three clades including two putative cryptic species in addition to T. dimidiata sensu stricto. Neither the cyt b phylogeny nor hypothesis testing support the proposed subspecies inferred from ITS-2. Additionally, the two cryptic species are supported by phylogenies inferred from mitochondrially-encoded genes cytochrome c oxidase I and NADH dehydrogenase 4. In summary, our results reveal two cryptic species. Phylogenetic relationships indicate T. dimidiata sensu stricto is not subdivided into monophyletic clades consistent with subspecies. Based on increased support by hypothesis testing, we propose an updated systematic hypothesis for T. dimidiata based on extensive taxon sampling and analysis of both mitochondrial and nuclear genes.
authors: Department of Biological Sciences, Loyola University New Orleans, New Orleans, LA, United States. Electronic address: dorn@loyno.edu.
authors: Patricia L
authors: PL
authors: Dorn
authors: Department of Biological Sciences, Loyola University New Orleans, New Orleans, LA, United States; Department of Biology, University of Vermont, Burlington, VT, United States.
authors: Nicholas M
authors: NM
authors: de la Rúa
authors: Department of Biology, University of Vermont, Burlington, VT, United States.
authors: Heather
authors: H
authors: Axen
authors: Department of Biology, University of Vermont, Burlington, VT, United States.
authors: Nicholas
authors: N
authors: Smith
authors: Department of Biological Sciences, Loyola University New Orleans, New Orleans, LA, United States.
authors: Bethany R
authors: BR
authors: Richards
authors: Department of Biology, University of Vermont, Burlington, VT, United States.
authors: Jirias
authors: J
authors: Charabati
authors: Department of Biological Sciences, Loyola University New Orleans, New Orleans, LA, United States.
authors: Julianne
authors: J
authors: Suarez
authors: Department of Biological Sciences, Loyola University New Orleans, New Orleans, LA, United States.
authors: Adrienne
authors: A
authors: Woods
authors: Department of Biological Sciences, Loyola University New Orleans, New Orleans, LA, United States.
authors: Rafaela
authors: R
authors: Pessoa
authors: Biology School, University of San Carlos, Guatemala City, Guatemala.
authors: Carlota
authors: C
authors: Monroy
authors: Department of Biology, University of Vermont, Burlington, VT, United States.
authors: C William
authors: CW
authors: Kilpatrick
authors: Department of Biology, University of Vermont, Burlington, VT, United States.
authors: Lori
authors: L
authors: Stevens
mesh_terms: D000818:Animals; D002489:Central America; D014355:Chagas Disease / Q000635:transmission*; D045303:Cytochromes b / Q000235:genetics; D021903:DNA, Ribosomal Spacer; D050259:Genes, Mitochondrial; D006239:Haplotypes; D006801:Humans; D007303:Insect Vectors / Q000145:classification* / Q000235:genetics* / Q000382:microbiology; D010802:Phylogeny; D058974:Phylogeography; D014224:Triatoma / Q000145:classification* / Q000235:genetics* / Q000382:microbiology; D014349:Trypanosoma cruzi
chemical_list: D021903:DNA, Ribosomal Spacer; D045303:Cytochromes b
keywords: Central America; Chagas disease; Insect vector; Phylogeny; Systematics; Triatoma dimidiata