• View in gallery

    Diakinesis (A) and metaphase I (B) of hybrids resulting from the experimental cross between T. bahiensis female × T. lenti male. Note the univalent autosomes (arrow). Y = Y sex chromosome; X = X sex chromosome. Bar: 10 μm.

  • 1.

    World Health Organization, 2017. Chagas Disease (American Trypanosomiasis). Available at: http://www.who.int/mediacentre/factsheets/fs340/en/. Accessed April 2, 2017.

  • 2.

    Galvão C, 2014. Vetores da doença de chagas no Brasil. Curitiba, Brazil: Sociedade Brasileira de Zoologia.

  • 3.

    Mendonça VJ, Alevi KCC, Pinotti H, Gurgel-Gongalves R, Pita S, Guerra AL, Panzera F, Araújo RF, Azeredo-Oliveira MTV, Rosa JA, 2016. Revalidation of Triatoma bahiensis Sherlock & Serafim, 1967 (Hemiptera: Reduviidae) and phylogeny of the T. brasiliensis species complex. Zootaxa 4107: 239254.

    • Search Google Scholar
    • Export Citation
  • 4.

    Costa J, Almeida CE, Dotson EM, Lins A, Vinhaes M, Silveira AC, Beard CB, 2003. The epidemiologic importance of Triatoma brasiliensis as a Chagas disease vector in Brazil: a revision of domiciliary captures during 1993–1999. Mem Inst Oswaldo Cruz 98: 443449.

    • Search Google Scholar
    • Export Citation
  • 5.

    Souza ES, Von Atzingen NCB, Furtado MB, Oliveira J, Nascimento JD, Vendrami DP, Gardim S, Rosa JA, 2016. Description of Rhodnius marabaensis sp. n. (Hemiptera, Reduviidae, Triatominae) from Pará State, Brazil. ZooKeys 621: 4562.

    • Search Google Scholar
    • Export Citation
  • 6.

    Rosa JA, Justino HHG, Nascimento JD, Mendonça VJ, Rocha CS, Carvalho DB, Falcone R, Azeredo-Oliveira MTV, Alevi KCC, Oliveira J, 2017. A new species of Rhodnius from Brazil (Hemiptera, Reduviidae, Triatominae). Zookeys 675: 125.

    • Search Google Scholar
    • Export Citation
  • 7.

    Mendonça VJ, Oliveira J, Rimoldi A, Ferreira Filho JC, Araújo RF, Rosa JA, 2015. Triatominae survey (Hemiptera: Heteroptera: Reduviidae) in the south-central region of the State of Bahia, Brazil between 2008 and 2013. Am J Trop Med Hyg 92: 10761080.

    • Search Google Scholar
    • Export Citation
  • 8.

    Lent H, Wygodzinsky P, 1979. Revision of the Triatominae (Hemiptera, Reduviidae), and their significance as vectors of Chagas’s disease. Bull Am Mus Nat Hist 163: 123520.

    • Search Google Scholar
    • Export Citation
  • 9.

    Mayr E, 1996. What is a species, and what is not? Philos Sci 63: 262277.

  • 10.

    Usinger RL, Wygodzinsky P, Ryckman RE, 1966. The biosystematics of Triatominae. Annu Rev Entomol 11: 309330.

  • 11.

    Pérez R, Hérnandez M, Quintero O, Scvortzoff E, Canale D, Méndez L, Cohanoff C, Martino M, Panzera F, 2005. Cytogenetic analysis of experimental hybrids in species of Triatominae (Hemiptera–Reduviidae). Genetica 125: 261270.

    • Search Google Scholar
    • Export Citation
  • 12.

    Mendonça VJ, Alevi KC, Medeiros LM, Nascimento JD, de Azeredo-Oliveira MT, da Rosa JA, 2014. Cytogenetic and morphologic approaches of hybrids from experimental crosses between Triatoma lenti Sherlock & Serafim, 1967 and T. sherlocki Papa et al., 2002 (Hemiptera: Reduviidae). Infect Genet Evol 26: 123131.

    • Search Google Scholar
    • Export Citation
  • 13.

    Espínola HN, 1971. Reproductive isolation between Triatoma brasiliensis Neiva, 1911 and Triatoma petrochii Pinto & Barretto, 1925 (Hemiptera Reduviidae). Rev Bras Biol 31: 277281.

    • Search Google Scholar
    • Export Citation
  • 14.

    Costa J, Almeida CE, Dujardin JP, Beard CB, 2003. Crossing experiments detect genetic incompatibility among populations of Triatoma brasiliensis Neiva, 1911 (Heteroptera, Reduviidae, Triatominae). Mem Inst Oswaldo Cruz 98: 637639.

    • Search Google Scholar
    • Export Citation
  • 15.

    Costa J, Argolo AN, Felix M, 2006. Redescription of Triatoma melanica Neiva & Lent, 1941, new status (Hemiptera: Reduviidae: Triatominae). Zootaxa 1385: 4752.

    • Search Google Scholar
    • Export Citation
  • 16.

    Campos-Soto R, Panzera F, Pita S, Lages C, Solari A, Botto-Mahan C, 2016. Experimental crosses between Mepraia gajardoi and M. spinolai and hybrid chromosome analyses reveal the occurrence of several isolation mechanisms. Infect Genet Evol 45: 205212.

    • Search Google Scholar
    • Export Citation
  • 17.

    De Vaio ES, Grucci B, Castagnino AM, Franca ME, Martinez ME, 1985. Meiotic differences between three triatomine species (Hemiptera:Reduviidae). Genetica 67: 185191.

    • Search Google Scholar
    • Export Citation
  • 18.

    Alevi KCC, Mendonça PP, Pereira NP, Rosa JA, Azeredo-Oliveira MTV, 2012. Karyotype of Triatoma melanocephala Neiva and Pinto (1923). Does this species fit in the brasiliensis subcomplex? Infect Genet Evol 12: 16521653.

    • Search Google Scholar
    • Export Citation
  • 19.

    Riley R, 1966. The secondary pairing of bivalents with genetically similar chromosomes. Nature 185: 751752.

  • 20.

    Sherlock IA, Serafim EM, 1967. Triatoma lenti sp. n., Triatoma pessoai sp. n. e Triatoma bahiensis sp. n. do Estado da Bahia, Brasil (Hemiptera, Reduviidae). Gaz Méd Bahia 67: 7592.

    • Search Google Scholar
    • Export Citation
  • 21.

    Díaz S, Panzera F, Jaramillo-O N, Pérez R, Fernández R, Vallejo G, Saldaña A, Calzada JE, Triana O, Gómez-Palácio A, 2014. Genetic, cytogenetic and morphological trends in the evolution of the Rhodnius (Triatominae: Rhodniini) trans-Andean group. PLoS One 9: e87493.

    • Search Google Scholar
    • Export Citation
  • 22.

    Schereiber G, Pinho AC, Parentoni R, Salgado AA, Godoi TL Jr, 1974. Cytogenetics of Triatominae: II Spermatogenesis in hybrid between Triatoma infestans and Triatoma pseudomaculata (Hemiptera, Reduviidae). Rev Bras Biol 31: 19.

    • Search Google Scholar
    • Export Citation
  • 23.

    Sherlock IA, Guitton N, 1974. Fauna Triatominae do Estado da Bahia Brasil III: notas sobre ecótopos silvestres e o gênero Psammolestes. Mem Inst Oswaldo Cruz 72: 91101.

    • Search Google Scholar
    • Export Citation
  • 24.

    Ribeiro AR, Mendonça VJ, Alves RT, Martinez I, Araújo RF, Melo F, Rosa JA, 2014. Trypanosoma cruzi strains from triatomine collected in Bahia and Rio Grande do Sul, Brazil. Rev Saude Publica 48: 295302.

    • Search Google Scholar
    • Export Citation
 
 
 

 

 
 
 

 

 

 

 

 

 

Hybrid Collapse Confirms the Specific Status of Triatoma bahiensis Sherlock and Serafim, 1967 (Hemiptera, Triatominae), an Endemic Species in Brazil

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  • 1 Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho” – IBILCE/UNESP, São José do Rio Preto, São Paulo, Brazil;
  • | 2 Departamento de Ciências Biológicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista “Júlio de Mesquita Filho”, FCFAR/UNESP, Araraquara, São Paulo, Brazil;
  • | 3 Secretaria Estadual de Saúde da Bahia – SESAB/Divisão de Entomologia, Centro Administrativo da Bahia, Salvador, Bahia, Brazil;
  • | 4 Departamento de Parasitologia e Microbiologia, Centro de Ciências da Saúde, Universidade Federal do Piauí, UFPI, Campus Ministro Petrônio Portella, Teresina, Piauí, Brazil

Six to seven million people worldwide are estimated to be infected with Trypanosoma cruzi, the etiologic agent of Chagas disease transmitted mainly by triatomines. Triatoma bahiensis was recently collected in the Brazilian state of Bahia and revalidated using different approaches. The main criterion used to define a “good” biological species is reproductive isolation, so we evaluated the cytogenetics of first-generation (F1) hybrids resulting from the experimental cross between T. bahiensis females and Triatoma lenti males to possibly characterize the postzygotic isolation associated with the hybrid breakdown. All cells analyzed presented a karyotype of 2n = 22 and a pair of univalent autosomes. This chromosome behavior represents hybrid collapse and underscores the specific status of T. bahiensis. Thus, we have characterized the presence of the hybrid collapse phenomenon in an experimental cross, and we confirm the specific status of T. bahiensis, thus contributing to the Triatominae taxonomy.

Six million to seven million people worldwide are estimated to be infected with Trypanosoma cruzi (Chagas, 1909), the parasite which causes Chagas disease.1 In Latin America, T. cruzi parasites are mainly transmitted by contact with feces or urine of infected blood-sucking triatomine bugs, and vector control is considered the most useful method for preventing Chagas disease.1

In Brazil, there are currently 68 triatomine species distributed throughout the country’s 27 states.26 In the state of Bahia, there are 25 species distributed among the genera Cavernicola (one species), Eratyrus (one species), Panstrongylus (five species), Psammolestes (one species), Rhodnius (three species), and Triatoma (14 species).24

Triatoma bahiensis Sherlock and Serafim, 1967 was recently collected in the south-central region of the Brazilian state of Bahia in an area known to be endemic for Triatoma lenti.7 For more than three decades, T. bahiensis was considered to be synonymous with T. lenti Sherlock and Serafim, 1967.8 Mendonça et al.3 used morphological, morphometric, molecular, cytogenetic, and experimental crosses to revalidate T. bahiensis. Although neither cytogenetic analysis (same characteristics) nor molecular analysis (relatively low genetic distance) generated enough support for the differentiation between T. bahiensis and T. lenti, the low viability of experimental crosses combined with morphological and morphometric data do, in fact, allow for this differentiation.3 These tools have corroborated the phylogenetic relationship between the Triatoma brasiliensis complex and T. bahiensis.3

The main criterion that defines a “good” biological species is reproductive isolation; however, this type of insulation must be considered under natural conditions.9 Thus, although experimental crosses under laboratory conditions are not conclusive, they provide important knowledge on the evolutionary phenomena involved in the conceptualization of biological species (reproductive isolation).

In the subfamily Triatominae, several events involving prezygotic isolation (for example, mechanical isolation)10 have been observed, as have events involving reproductive postzygotic isolation—most commonly as sterility11 and hybrid collapse.12 Experimental crosses have proven to be important in the taxonomy of the T. brasiliensis complex: the specific status of Triatoma petrocchiae Pinto and Barreto, 1925 was confirmed by reproductive isolation when crossed with T. brasiliensis Neiva, 1911 (the eggs did not hatch);13 genetic incompatibility was found between melanica populations of T. brasiliensis and T. brasiliensis,14 which provided important evidence for the revalidation of Triatoma melanica Costa, Argolo and Felix, 2006 as species;15 and, more recently, the occurrence of hybrid collapse has corroborated the specific status of T. lenti and Triatoma sherlocki Papa, Jurberg, Carcavallo, Cerqueira and Barata, 2002.12

Because the experimental cross between T. bahiensis and T. lenti produced hybrids (which makes prezygotic isolation barriers unfeasible),3 we evaluated the cytogenetics of the first-generation (F1) hybrids to characterize the possible postzygotic isolation factors involved in the hybrid breakdown observed by Mendonça et al.3

Three adult male hybrids resulting from the experimental cross between T. bahiensis females and T. lenti males were analyzed cytogenetically. It is important to note that the reciprocal crosses between T. lenti females and T. bahiensis males resulted in only two adult females, and ovary analysis is not feasible in cytogenetic studies because meiotic stages are not usually observed in their ovaries;16 for more details on the conditions of experimental crosses, see Mendonça et al.3 The hybrids were dissected, and the testicles were removed and fixed in a methanol and acetic acid solution (3:1). Seminiferous tubules were shredded and smashed, and the microscope slides were set in liquid nitrogen. The coverslips were removed after the sample was frozen in liquid nitrogen and the biological material was fixed on the slides. The samples were then stained using the lacto-acetic orcein cytogenetic technique,17,18 and the genetic affinity between the parental species was evaluated through the pairings between the homeologous chromosomes of the hybrids during prophase (diakinesis) and metaphase I and II. At least 50 cells in different stages were observed, as per the classification provided by Campos-Soto et al.16

All of the cells analyzed presented a karyotype of 2n = 22 (20A + XY) and a pair of univalent autosomes (Figure 1A, B, arrow). This chromosome behavior shows that the cross between a T. bahiensis female and a T. lenti male is unviable because of the hybrid collapse. This finding underscores the specific status of T. bahiensis because two species have distinct genomes when their chromosomes differ in structure and gene content, and, as a result, no pairing occurs between one or more pairs of homeologous chromosomes during the meiosis of hybrids.19

Figure 1.
Figure 1.

Diakinesis (A) and metaphase I (B) of hybrids resulting from the experimental cross between T. bahiensis female × T. lenti male. Note the univalent autosomes (arrow). Y = Y sex chromosome; X = X sex chromosome. Bar: 10 μm.

Citation: The American Journal of Tropical Medicine and Hygiene 98, 2; 10.4269/ajtmh.17-0270

These findings show that, although T. bahiensis and T. lenti are considered morphologically related (differentiated initially by only two orange-red spots on each side of the corium),20 these species underwent genomic reorganization during speciation, as suggested by the speciation of Rhodnius colombiensis Mejia, Galvão and Jurberg, 1999 by means of the experimental crossing with Rhodnius pallescens Barber, 1932.21 The presence of univalent chromosomes results in unviable gametes, as has been described previously for other hybrids.11,22

Sherlock and Guitton23 collected T. lenti specimens in Bahia, and all were positive for T. cruzi. Recently, T. cruzi was again isolated from T. lenti from Bahia.24 Although there are no reports in the literature of T. bahiensis being infected by T. cruzi, we would like to call attention to the benefit of future entoepidemiological studies on the possible presence of T. bahiensis among the triatomines collected in this state to definitively determine the epidemiological importance of this species as a vector.

Thus, we characterize the presence of the hybrid collapse phenomenon in an experimental cross between T. bahiensis females and T. lenti males, and we confirm the specific status of T. bahiensis, thus contributing to the Triatominae taxonomy.

REFERENCES

  • 1.

    World Health Organization, 2017. Chagas Disease (American Trypanosomiasis). Available at: http://www.who.int/mediacentre/factsheets/fs340/en/. Accessed April 2, 2017.

  • 2.

    Galvão C, 2014. Vetores da doença de chagas no Brasil. Curitiba, Brazil: Sociedade Brasileira de Zoologia.

  • 3.

    Mendonça VJ, Alevi KCC, Pinotti H, Gurgel-Gongalves R, Pita S, Guerra AL, Panzera F, Araújo RF, Azeredo-Oliveira MTV, Rosa JA, 2016. Revalidation of Triatoma bahiensis Sherlock & Serafim, 1967 (Hemiptera: Reduviidae) and phylogeny of the T. brasiliensis species complex. Zootaxa 4107: 239254.

    • Search Google Scholar
    • Export Citation
  • 4.

    Costa J, Almeida CE, Dotson EM, Lins A, Vinhaes M, Silveira AC, Beard CB, 2003. The epidemiologic importance of Triatoma brasiliensis as a Chagas disease vector in Brazil: a revision of domiciliary captures during 1993–1999. Mem Inst Oswaldo Cruz 98: 443449.

    • Search Google Scholar
    • Export Citation
  • 5.

    Souza ES, Von Atzingen NCB, Furtado MB, Oliveira J, Nascimento JD, Vendrami DP, Gardim S, Rosa JA, 2016. Description of Rhodnius marabaensis sp. n. (Hemiptera, Reduviidae, Triatominae) from Pará State, Brazil. ZooKeys 621: 4562.

    • Search Google Scholar
    • Export Citation
  • 6.

    Rosa JA, Justino HHG, Nascimento JD, Mendonça VJ, Rocha CS, Carvalho DB, Falcone R, Azeredo-Oliveira MTV, Alevi KCC, Oliveira J, 2017. A new species of Rhodnius from Brazil (Hemiptera, Reduviidae, Triatominae). Zookeys 675: 125.

    • Search Google Scholar
    • Export Citation
  • 7.

    Mendonça VJ, Oliveira J, Rimoldi A, Ferreira Filho JC, Araújo RF, Rosa JA, 2015. Triatominae survey (Hemiptera: Heteroptera: Reduviidae) in the south-central region of the State of Bahia, Brazil between 2008 and 2013. Am J Trop Med Hyg 92: 10761080.

    • Search Google Scholar
    • Export Citation
  • 8.

    Lent H, Wygodzinsky P, 1979. Revision of the Triatominae (Hemiptera, Reduviidae), and their significance as vectors of Chagas’s disease. Bull Am Mus Nat Hist 163: 123520.

    • Search Google Scholar
    • Export Citation
  • 9.

    Mayr E, 1996. What is a species, and what is not? Philos Sci 63: 262277.

  • 10.

    Usinger RL, Wygodzinsky P, Ryckman RE, 1966. The biosystematics of Triatominae. Annu Rev Entomol 11: 309330.

  • 11.

    Pérez R, Hérnandez M, Quintero O, Scvortzoff E, Canale D, Méndez L, Cohanoff C, Martino M, Panzera F, 2005. Cytogenetic analysis of experimental hybrids in species of Triatominae (Hemiptera–Reduviidae). Genetica 125: 261270.

    • Search Google Scholar
    • Export Citation
  • 12.

    Mendonça VJ, Alevi KC, Medeiros LM, Nascimento JD, de Azeredo-Oliveira MT, da Rosa JA, 2014. Cytogenetic and morphologic approaches of hybrids from experimental crosses between Triatoma lenti Sherlock & Serafim, 1967 and T. sherlocki Papa et al., 2002 (Hemiptera: Reduviidae). Infect Genet Evol 26: 123131.

    • Search Google Scholar
    • Export Citation
  • 13.

    Espínola HN, 1971. Reproductive isolation between Triatoma brasiliensis Neiva, 1911 and Triatoma petrochii Pinto & Barretto, 1925 (Hemiptera Reduviidae). Rev Bras Biol 31: 277281.

    • Search Google Scholar
    • Export Citation
  • 14.

    Costa J, Almeida CE, Dujardin JP, Beard CB, 2003. Crossing experiments detect genetic incompatibility among populations of Triatoma brasiliensis Neiva, 1911 (Heteroptera, Reduviidae, Triatominae). Mem Inst Oswaldo Cruz 98: 637639.

    • Search Google Scholar
    • Export Citation
  • 15.

    Costa J, Argolo AN, Felix M, 2006. Redescription of Triatoma melanica Neiva & Lent, 1941, new status (Hemiptera: Reduviidae: Triatominae). Zootaxa 1385: 4752.

    • Search Google Scholar
    • Export Citation
  • 16.

    Campos-Soto R, Panzera F, Pita S, Lages C, Solari A, Botto-Mahan C, 2016. Experimental crosses between Mepraia gajardoi and M. spinolai and hybrid chromosome analyses reveal the occurrence of several isolation mechanisms. Infect Genet Evol 45: 205212.

    • Search Google Scholar
    • Export Citation
  • 17.

    De Vaio ES, Grucci B, Castagnino AM, Franca ME, Martinez ME, 1985. Meiotic differences between three triatomine species (Hemiptera:Reduviidae). Genetica 67: 185191.

    • Search Google Scholar
    • Export Citation
  • 18.

    Alevi KCC, Mendonça PP, Pereira NP, Rosa JA, Azeredo-Oliveira MTV, 2012. Karyotype of Triatoma melanocephala Neiva and Pinto (1923). Does this species fit in the brasiliensis subcomplex? Infect Genet Evol 12: 16521653.

    • Search Google Scholar
    • Export Citation
  • 19.

    Riley R, 1966. The secondary pairing of bivalents with genetically similar chromosomes. Nature 185: 751752.

  • 20.

    Sherlock IA, Serafim EM, 1967. Triatoma lenti sp. n., Triatoma pessoai sp. n. e Triatoma bahiensis sp. n. do Estado da Bahia, Brasil (Hemiptera, Reduviidae). Gaz Méd Bahia 67: 7592.

    • Search Google Scholar
    • Export Citation
  • 21.

    Díaz S, Panzera F, Jaramillo-O N, Pérez R, Fernández R, Vallejo G, Saldaña A, Calzada JE, Triana O, Gómez-Palácio A, 2014. Genetic, cytogenetic and morphological trends in the evolution of the Rhodnius (Triatominae: Rhodniini) trans-Andean group. PLoS One 9: e87493.

    • Search Google Scholar
    • Export Citation
  • 22.

    Schereiber G, Pinho AC, Parentoni R, Salgado AA, Godoi TL Jr, 1974. Cytogenetics of Triatominae: II Spermatogenesis in hybrid between Triatoma infestans and Triatoma pseudomaculata (Hemiptera, Reduviidae). Rev Bras Biol 31: 19.

    • Search Google Scholar
    • Export Citation
  • 23.

    Sherlock IA, Guitton N, 1974. Fauna Triatominae do Estado da Bahia Brasil III: notas sobre ecótopos silvestres e o gênero Psammolestes. Mem Inst Oswaldo Cruz 72: 91101.

    • Search Google Scholar
    • Export Citation
  • 24.

    Ribeiro AR, Mendonça VJ, Alves RT, Martinez I, Araújo RF, Melo F, Rosa JA, 2014. Trypanosoma cruzi strains from triatomine collected in Bahia and Rio Grande do Sul, Brazil. Rev Saude Publica 48: 295302.

    • Search Google Scholar
    • Export Citation

Author Notes

Address correspondence to Vagner José Mendonça, Departamento de Parasitologia e Microbiologia, Centro de Ciências da Saúde, Universidade Federal do Piauí, UFPI, Av. Universitária - lado ímpar, Ininga, 64049550 Teresina, PI, Brazil. E-mail: vagjose@hotmail.com

Financial support: The study was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (process numbers 2013/19764-0, Brazil) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil).

Authors’ addresses: Kaio Cesar Chaboli Alevi and Maria Tercília Vilela de Azeredo Oliveira, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho” – IBILCE/UNESP, Rua Cristóvão Colombo, 2265, 15054-000, São José do Rio Preto, SP, Brazil, E-mails: kaiochaboli@hotmail.com and tercilia@ibilce.unesp.br. Heloisa Pinotti and João Aristeu da Rosa, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista “Júlio de Mesquita Filho”, FCFAR/UNESP, Rodovia Araraquara-Jaú km 1, 14801-902, Araraquara, SP, Brazil, E-mails: helopinotti@hotmail.com and joaoaristeu@gmail.com. Renato Freitas Araújo, Secretaria Estadual de Saúde da Bahia – SESAB/Divisão de Entomologia, Av. Luis Viana Filho, 400 - Centro Administrativo da Bahia, 41745-900, Salvador, BA, Brazil, E-mail: birdeagle01@yahoo.com.br. Vagner José Mendonça, Centro de Ciências da Saúde, Universidade Federal do Piauí, UFPI, Av. Universitária - lado ímparIninga, 64049550 - Teresina, PI, Brazil, E-mail: vagjose@hotmail.com.

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