TOXIC HYDROGEN SULFIDE AND DARK CAVES: PHENOTYPIC AND GENETIC DIVERGENCE ACROSS TWO ABIOTIC ENVIRONMENTAL GRADIENTS IN POECILIA MEXICANA

  1. Michael Tobler1,2,3,†,
  2. Thomas J. DeWitt4,
  3. Ingo Schlupp2,
  4. Francisco J. García de León5,
  5. Roger Herrmann6,
  6. Philine G.D. Feulner6,7,
  7. Ralph Tiedemann6,
  8. Martin Plath6,8

Article first published online: 15 JUL 2008

DOI: 10.1111/j.1558-5646.2008.00466.x

Issue

Evolution

Evolution

Volume 62, Issue 10, pages 2643–2659, October 2008

Additional Information

How to Cite

Tobler, M., DeWitt, T. J., Schlupp, I., García de León, F. J., Herrmann, R., Feulner, P. G., Tiedemann, R. and Plath, M. (2008), TOXIC HYDROGEN SULFIDE AND DARK CAVES: PHENOTYPIC AND GENETIC DIVERGENCE ACROSS TWO ABIOTIC ENVIRONMENTAL GRADIENTS IN POECILIA MEXICANA. Evolution, 62: 2643–2659. doi: 10.1111/j.1558-5646.2008.00466.x

Author Information

  1. 1

    Institute of Zoology, University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland

  2. 2

    Department of Zoology, University of Oklahoma, Norman, Oklahoma 73019

  3. 3

    E-mail: michi.tobler@gmail.com

  4. 4

    Department of Wildlife and Fisheries Sciences, Texas A&M University, 2258 TAMU, College Station, Texas 77843

  5. 5

    Centro de Investigaciones Biológicas del Noroeste (Conservation Genetics Laboratory), La Paz, Baja California, 23090 México

  6. 6

    Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-26, 14476 Potsdam, Germany

  7. 7

    Department of Animal & Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 1TN, United Kingdom

  8. 8

    Unit of Animal Ecology, Institute of Biochemistry and Biology, University of Potsdam, Maulbeerallee 1, 14469 Potsdam, Germany

  1. †

    Present address: Department of Biology and Department of Wildlife and Fisheries Sciences, Texas A&M University, 2258 TAMU, College Station, Texas 77843-2358

Publication History

  1. Issue published online: 1 OCT 2008
  2. Article first published online: 15 JUL 2008
  3. Received April 20, 2008Accepted June 17, 2008

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Keywords:

  • Abiotic environmental conditions;
  • cave evolution;
  • divergent natural selection;
  • ecological speciation;
  • extremophile;
  • local adaptation;
  • Poeciliidae;
  • reproductive isolation

Divergent natural selection drives evolutionary diversification. It creates phenotypic diversity by favoring developmental plasticity within populations or genetic differentiation and local adaptation among populations. We investigated phenotypic and genetic divergence in the livebearing fish Poecilia mexicana along two abiotic environmental gradients. These fish typically inhabit nonsulfidic surface rivers, but also colonized sulfidic and cave habitats. We assessed phenotypic variation among a factorial combination of habitat types using geometric and traditional morphometrics, and genetic divergence using quantitative and molecular genetic analyses. Fish in caves (sulfidic or not) exhibited reduced eyes and slender bodies. Fish from sulfidic habitats (surface or cave) exhibited larger heads and longer gill filaments. Common-garden rearing suggested that these morphological differences are partly heritable. Population genetic analyses using microsatellites as well as cytochrome b gene sequences indicate high population differentiation over small spatial scale and very low rates of gene flow, especially among different habitat types. This suggests that divergent environmental conditions constitute barriers to gene flow. Strong molecular divergence over short distances as well as phenotypic and quantitative genetic divergence across habitats in directions classic to fish ecomorphology suggest that divergent selection is structuring phenotypic variation in this system.

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