Hsp70 protein levels and thermotolerance in Drosophila subobscura: a reassessment of the thermal co-adaptation hypothesis

Authors

  • G. CALABRIA,

    1. Departament de Genètica, Grup de Biologia Evolutiva (GBE)/Institut de Recerca de la Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
    Search for more papers by this author
  • O. DOLGOVA,

    1. Departament de Genètica i de Microbiologia, Grup de Biologia Evolutiva (GBE), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
    Search for more papers by this author
  • C. REGO,

    1. Departamento de Ciências Agrárias, Azorean Biodiversity Group-CITAA, Universidade dos Açores, Terra-Chã, Angra do Heroísmo, Portugal
    Search for more papers by this author
  • L. E. CASTAÑEDA,

    1. Departament de Genètica i de Microbiologia, Grup de Biologia Evolutiva (GBE), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
    2. Instituto de Ecología y Evolución, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
    Search for more papers by this author
  • E. L. REZENDE,

    1. Departament de Genètica i de Microbiologia, Grup de Biologia Evolutiva (GBE), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
    Search for more papers by this author
  • J. BALANYÀ,

    1. Departament de Genètica, Grup de Biologia Evolutiva (GBE)/Institut de Recerca de la Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
    Search for more papers by this author
  • M. PASCUAL,

    1. Departament de Genètica, Grup de Biologia Evolutiva (GBE)/Institut de Recerca de la Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
    Search for more papers by this author
  • J. G. SØRENSEN,

    1. Department of Bioscience, Aarhus University, Aarhus, Denmark
    Search for more papers by this author
  • V. LOESCHCKE,

    1. Department of Bioscience, Aarhus University, Aarhus, Denmark
    Search for more papers by this author
  • M. SANTOS

    1. Departament de Genètica i de Microbiologia, Grup de Biologia Evolutiva (GBE), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
    Search for more papers by this author

Gemma Calabria, Departament de Genètica, Grup de Biologia Evolutiva (GBE), Facultat de Biologia, Universitat de Barcelona, Diagonal 643, 08028 Barcelona, Spain.
Tel.: +34 93 493 5801; fax: +34 93 403 4420;
e-mail: gemmacalabria@ub.edu

Abstract

Theory predicts that geographic variation in traits and genes associated with climatic adaptation may be initially driven by the correlated evolution of thermal preference and thermal sensitivity. This assumes that an organism’s preferred body temperature corresponds with the thermal optimum in which performance is maximized; hence, shifts in thermal preferences affect the subsequent evolution of thermal-related traits. Drosophila subobscura evolved worldwide latitudinal clines in several traits including chromosome inversion frequencies, with some polymorphic inversions being apparently associated with thermal preference and thermal tolerance. Here we show that flies carrying the warm-climate chromosome arrangement O3+4 have higher basal protein levels of Hsp70 than their cold-climate Ost counterparts, but this difference disappears after heat hardening. O3+4 carriers are also more heat tolerant, although it is difficult to conclude from our results that this is causally linked to their higher basal levels of Hsp70. The observed patterns are consistent with the thermal co-adaptation hypothesis and suggest that the interplay between behaviour and physiology underlies latitudinal and seasonal shifts in inversion frequencies.

Ancillary