Antennal Phenotype of <I>Triatoma dimidiata</I> Populations and Its Relationship with Species of <I>phyllosoma</I> and <I>protracta</I> Complexes

Abstract

Triatoma dimidiata (Latreille 1811) Reduviidae Triatominae is the main vector of Chagas disease in several countries of Latin America. As for other vector species, the characterization of T. dimidiata subpopulations within particular geographical regions or occupying different habitats could help in better planning of vector control actions. A first objective in this study was to evaluate the antennal phenotype as a phenetic marker to characterize populations of T. dimidiata collected in different geographic areas and domestic and sylvatic habitats. A second objective was to evaluate the phenetic relationships of T. dimidiata with other species of the phyllosoma complex: longipennis, pallidipennis, and phyllosoma. The antennal sensilla of T. dimidiata specimens collected in Mexico, Central America, and Colombia were analyzed and compared with the antennal sensilla of T. longipennis, T. pallidipennis, and T. phyllosoma. T. barberi was used as an outgroup in the analysis. For each specimen, the ventral side of the three distal segments of the antennae was drawn, identifying and counting four types of sensilla. In T. dimidiata, univariate and multivariate analysis showed differences between sexes, among populations collected in different habitats within the same region, and among populations collected in different geographic regions. Two types of antennal sensilla showed a latitudinal variation. Domestic specimens showed intermediate characteristics of the antennal phenotype, between sylvatic cave- and sylvatic forest-collected specimens. The antennal phenotypes show high similarities among T. pallidipennis, T. phyllosoma, and T. longipennis, with a better differentiation of T. pallidipennis. T. dimidiata is separated from the other members of the complex by a similar distance to T. barberi, of the protracta complex.

Analysis of antenal sensilla patterns of Rhodnius prolixus from Colombia and Venezuela

“…Only one antenna was examined from each specimen. Four sensilla types were used for analysis: BR, mechanoreceptive bristles, BA, basiconics, TH, thin walled trichoids, TK, thick-walled trichoids; these sensilla have showns to be significant in differentiating Triatominae populations (Catala & Dujardin 2001, Catalá et al 2004, 2005. A total of 53 insects (27 males and 26 females) was included in the analysis.…”

Genetics and evolution of triatomines: from phylogeny to vector control

“…The current classification of the Triatominae into five tribes and 15 genera is largely based on morphological characters, including chromatic ones (Lent and Wygodzinsky, 1979). The most commonly used characters are head and wing shape (Dujardin et al, 1999b;dos Santos et al, 2003;Dumonteil et al, 2007), but a number of other characters have been used such as the structure of the male genitalia (Obara et al, 2007), the egg (dos Santos et al, 2009), antenna (Silva et al, 2002;Catala et al, 2005) and rostrum (Silva et al, 2003). Within the triatomines, for example, the monophylly of the Rhodiniini tribe has been supported by apical antenna insertion, body forms, post-ocular callosities, male genital characteristics, egg surface architecture and salivary gland protein composition (Tartarotti et al, 2006).…”

Variación del fenotipo antenal de poblaciones del domicilio, peridomicilio y silvestres de Triatoma dimidiata (Hemiptera: Reduviidae) en Santander, Colombia

“…En los triatominos una serie de cambios morfológicos y genéticos se han asociado a la adaptación a hábitats domésticos, y se ha señalado que la densidad de sensilias antenales disminuye progresivamente en el pedicelo y sobre el total de la antena en especies que viven en "hábitats estables" como la vivienda humana (16)(17)(18)22,23); sin embargo, este término puede usarse de manera ambigua, puesto que, además de las fluctuaciones ambientales, en un hábitat intervienen la explotación de diferentes recursos tróficos, espaciales y reproductivos, los cuales podrían modificar en forma particular el fenotipo de las sensilias antenales.…”

“…En triatominos, el fenotipo antenal refleja modificaciones de los patrones ancestrales por la adaptación a diferentes hábitats y hospederos (16)(17)(18) y es útil en la diferenciación intraespecífica, Este estudio, primero en poblaciones de T. dimidiata de Colombia, se realizó para detectar variaciones en cuatro receptores antenales en los diferentes hábitats conocidos de una misma área geográfica y como contribución al conocimiento de la bioecología y ecoepidemiología de esta especie, y como orientación para metodologías de control vectorial en la zona endémica.…”