Bottlenecks and multiple introductions: population genetics of the vector of avian malaria in Hawaii

Authors

  • Dina M. Fonseca,

    Corresponding author
    1. Molecular Genetics Laboratory — DZR, National Zoological Park, Smithsonian Institution, 3001 Connecticut Avenue NW, Washington, DC 20008,
      ‡Present address: Walter Reed Biosystematics Unit, MSC-Smithsonian Institution, 4210 Silver Hill Rd., Suitland, MD 20746, USA. E-mail: D. M. Fonseca.‡Present address: Walter Reed Biosystematics Unit, MSC-Smithsonian Institution, 4210 Silver Hill Rd., Suitland, MD 20746, USA. E-mail:dfonseca@erols.com
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  • Dennis A. Lapointe,

    1. Wildlife Disease Laboratory, USGS-BRD-PIERC, Hawaii National Park, HI 96718, USA
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  • Robert C. Fleischer

    1. Molecular Genetics Laboratory — DZR, National Zoological Park, Smithsonian Institution, 3001 Connecticut Avenue NW, Washington, DC 20008,
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D. M. Fonseca.‡Present address: Walter Reed Biosystematics Unit, MSC-Smithsonian Institution, 4210 Silver Hill Rd., Suitland, MD 20746, USA. E-mail:dfonseca@erols.com

Abstract

Avian malaria has had a profound impact on the demographics and behaviour of Hawaiian forest birds since its vector, Culex quinquefasciatus the southern house mosquito, was first introduced to Hawaii around 1830. In order to understand the dynamics of the disease in Hawaii and gain insights into the evolution of vector-mediated parasite–host interactions in general we studied the population genetics of Cx. quinquefasciatus in the Hawaiian Islands. We used both microsatellite and mitochondrial loci. Not surprisingly we found that mosquitoes in Midway, a small island in the Western group, are quite distinct from the populations in the main Hawaiian Islands. However, we also found that in general mosquito populations are relatively isolated even among the main islands, in particular between Hawaii (the Big Island) and the remaining Hawaiian Islands. We found evidence of bottlenecks among populations within the Big Island and an excess of alleles in Maui, the site of the original introduction. The mitochondrial diversity was typically low but higher than expected. The current distribution of mitochondrial haplotypes combined with the microsatellite information lead us to conclude that there have been several introductions and to speculate on some processes that may be responsible for the current population genetics of vectors of avian malaria in Hawaii.

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