Hybridization and population structure of the Culex pipiens complex in the islands of Macaronesia

Authors

  • Bruno Gomes,

    1. Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    2. Centro de Malária e outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    Search for more papers by this author
  • Joana Alves,

    1. Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    2. Centro de Malária e outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    3. Direcção-Geral da Saúde Ministério da Saúde, Praia, Cabo Verde
    Search for more papers by this author
  • Carla A. Sousa,

    1. Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    2. Unidade de Parasitologia e Microbiologia Médicas, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    Search for more papers by this author
  • Marta Santa-Ana,

    1. Centro de Estudos da Macaronésia, Universidade da Madeira, Funchal, Portugal
    Search for more papers by this author
  • Inês Vieira,

    1. Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    2. Centro de Malária e outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    Search for more papers by this author
  • Teresa L. Silva,

    1. Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    2. Centro de Malária e outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    Search for more papers by this author
  • António P.G. Almeida,

    1. Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    2. Unidade de Parasitologia e Microbiologia Médicas, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    Search for more papers by this author
  • Martin J. Donnelly,

    1. Vector Group, Liverpool School of Tropical Medicine, Liverpool, UK
    Search for more papers by this author
  • João Pinto

    Corresponding author
    1. Centro de Malária e outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    • Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
    Search for more papers by this author

  • Funding Information This study was funded by Fundação para a Ciência e a Tecnologia, Portugal (POCI/BIA-BDE/57650/2004 and PPCDT/BIA-BDE/57650/2004; PPCDT/SAU-ESP/55110/2004). Joana Alves and Bruno Gomes were funded by a PhD fellowship of Fundação para a Ciência e Tecnologia/MCTES (SFRH/BD/153451/2005, SFRH/BD/36410/2007).

Correspondence

João Pinto, Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisbon, Portugal. Tel: +351 213652626 / +351 213622458; Fax: +351 213622458; E-mail: jpinto@ihmt.unl.pt

Abstract

The Culex pipiens complex includes two widespread mosquito vector species, Cx. pipiens and Cx. quinquefasciatus. The distribution of these species varies in latitude, with the former being present in temperate regions and the latter in tropical and subtropical regions. However, their distribution range overlaps in certain areas and interspecific hybridization has been documented. Genetic introgression between these species may have epidemiological repercussions for West Nile virus (WNV) transmission. Bayesian clustering analysis based on multilocus genotypes of 12 microsatellites was used to determine levels of hybridization between these two species in Macaronesian islands, the only contact zone described in West Africa. The distribution of the two species reflects both the islands' biogeography and historical aspects of human colonization. Madeira Island displayed a homogenous population of Cx. pipiens, whereas Cape Verde showed a more intriguing scenario with extensive hybridization. In the islands of Brava and Santiago, only Cx. quinquefasciatus was found, while in Fogo and Maio high hybrid rates (~40%) between the two species were detected. Within the admixed populations, second-generation hybrids (~50%) were identified suggesting a lack of isolation mechanisms. The observed levels of hybridization may locally potentiate the transmission to humans of zoonotic arboviruses such as WNV.

Ancillary