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Chromosome numbers in the Triatominae (Hemiptera-Reduviidae): a review


The chromosome numbers of 46 out of the 122 currently recognized species of Triatominae (Hemiptera, Reduviidae) are summarized. We present the number of autosomes, the sex mechanism and the first reference for each karyotype.

Chagas disease; cytogenetics; holocentric chromosomes; Triatominae


Chromosome numbers in the Triatominae (Hemiptera-Reduviidae): a review

Francisco PanzeraI, + + Corresponding author. E-mail: ; Ruben PérezII; Sonia HornosII; Yanina PanzeraI; Rosario CestauII; Verónica DelgadoI; Paula NicoliniI

ISección Genética Evolutiva, Facultad de Ciencias, Universidad de la República, Tristán Narvaja 1674, 11200 Montevideo, Uruguay

IIDepartamento de Genética, Facultad de Medicina, General Flores 2125, 11800 Montevideo, Uruguay


The chromosome numbers of 46 out of the 122 currently recognized species of Triatominae (Hemiptera, Reduviidae) are summarized. We present the number of autosomes, the sex mechanism and the first reference for each karyotype.

Key words: Chagas disease - cytogenetics - holocentric chromosomes -Triatominae

The subfamily Triatominae (Hemiptera-Reduviidae) includes 122 species of hematophagous insects and is divided into five tribes and 15 genera. Schofield (1994) lists 118 species of Triatominae, to which should now be added Belminus laportei (Lent et al. 1995), Rhodnius stali (Lent et al. 1993), Triatoma melanosoma (Lent et al. 1994), and T. gomeznunezi (Martínez et al. 1994).

Triatomines present holocentric chromosomes, which do not have a morphologically differentiated centromere. This feature, together with their small size, hindered the progress in studies of their cytogenetics, which, for a long time, were restricted to descriptions of chromosome number and sex mechanism with conventional staining.

In spite of their medical importance as vectors of Chagas disease, chromosomal studies are limited to a small number of species. Previous revisions reported the chromosome complements (haploid and diploid) of 29 species (Ueshima 1966, 1979). The purpose of this report is to summarize the chromosome numbers of the 46 cytogenetically studied species up to date (Table). Four of them are described for the first time in this paper (Rhodnius pallescens, Triatoma melanosoma, T. picturata and T. tibiamaculata).

Table shows that triatomines have a high chromosomal homogeneity. The most common number of autosomes (A) is 20, with only three exceptions: Triatoma nitida and Panstrongylus megistus (both with 18 A) and T.rubrofasciata (22 A). Three sex mechanisms are found in the males: XY (25 species), X1X2Y (19 species) and X1X2X3Y (2 species). In order to verify these multiple sex mechanisms it would be necessary to confirm them in females.

At present, species differentiation (Pérez et al. 1992), intraspecific variations (Panzera et al. 1992) and evolutionary relationships (Panzera et al. 1995) can all be better studied with the aid of banding techniques and the detailed analysis of meiotic chromosome behaviour. This cytogenetic approach is a useful tool for clarifying taxonomic uncertainties, particularly in those groups of epidemiological importance. These studies may allow the differentiation of morphologically similar species such as those belonging to the phyllosoma complex and sordida group. On the other hand, different populations within a given species can be identified. This could be the case for T. brasiliensis and T. infestans from Bolivia, where sylvatic and domestic populations may be distinguished on the basis of their cytogenetic differences.


To Dr J Jurberg (Laboratório Nacional e Interna-cional de Referência em Taxonomia de Triatomíneos, Instituto Oswaldo Cruz, Rio de Janeiro, Brasil) for providing many species studied here. To Dr C Schofield and JP Dujardin for their valuable comments on the manuscript. +Corresponding author. E-mail:

Received 31 October 1995

Accepted 8 February 1996

This research is sponsored by CSIC, CONICYT, PEDECIBA (Uruguay), equipment donation to the Government of Japan and European Communities grants (TS3*CT 91-0029, TS3*CT 92-0092, TS3*CT 92-0130).

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  • +
    Corresponding author. E-mail:
  • Publication Dates

    • Publication in this collection
      02 Oct 2008
    • Date of issue
      Aug 1996


    • Accepted
      08 Feb 1996
    • Received
      31 Oct 1995
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